DESCRIPTION SEALING COMPOSITION FOR SEMICONDUCTOR, SEMICONDUCTOR DEVICE AND METHOD OF PRODUCING THE SAME, AND POLYMER AND METHOD OF PRODUCING THE SAME TECHNICAL FIELD [0001] The present invention relates to a sealing composition for a semiconductor, a sen~iconductord evice and a method of producing the semiconductor device, and a polymer and a method of producing the polymer. BACKGROUND ART [0002] In the semiconductor device field in which scaling is advanced, various kinds of low dielectric constant materials (hereinafter, referred to as "low-k materials" in some cases) having a porous structure have been investigated as an interlayer dielectric layer of semiconductor. If the porosity of the semiconductor interlayer dielectric layer having a porous structure is increased in order to further lower the dielectric constant thereof, metal components such as coppel; which is embedded as a wiring material, or plasma components (at least one of radical or ion, the same shall apply hereinafter) caused by plasma treatment are prone to enter into the pores in the sen~iconductorin terlayer dielectric layer, and thus the dielectric constant thereof increases or leakage current occurs in some cases. in addition, metal conlpomnts or plasnla con~ponentsd iffuse even into a non-porous interlayer dielectric layer in some cases, and thus dielectric constant increases or leakage current occurs in the same manner as in a porous interlayer dielectric layer in some cases. [0003] Meanwhile, a technique is known in which pores on the side wall surface of a groove formed by etching is sealed using a surfactant in a micelle state in wet cleaning after etching in a production method of semiconductor device using a porous low dielectric constant material (for example, see Japanese National-Phase Publication (JP-A) No. 2009-503879). In addition, a teclnliqne is known in which the hydrophilicity and hydrophobicity of a low-k material is controlled by applying a polyvinyl alcohol-based amphiphilic polynler on the surface of the low-k material in a case in which the low-k material has a hydrophobic surface (for example, see International Publication No. WO 09/012184). 1 Moreover, a composition for semiconductor polishing containing a cationic polymer and a surfactant is known (for example, see Japanese Patent Application Laid-Open (JP-A) No. 2006-352042). DISCLOSURE OF INVENTION TECHNICAL PROBLEM [0004] In the technique disclosed in JP-ANo. 2009-503879 above, there is a case in which a surfactant having no micelle structure enters into a pore in the side wall surface of a groove, and thus the relative dielectric constant increases. In addition, there is a case in which adhesion between the interlayer dielectric layer and the wiring material is deteriorated by a micelle. In addition, in the technique disclosed in WO 091012184 above, a bulky layer is prone to be formed by hydrogen bonding between the polyvinyl alcohol-based amphiphilic polymers, and by viltt~eo f this, the relative dielectric constant of the interlayer dielectric layer increases in some cases or the adhesion between the interlayer dielectric layer and the wiring material deteriorates in some case. [0005] In addition, a sealing composition for a semiconductor exhibiting a superior sealing property with respect to an interlayer dielectric layer is desired in some cases. Accordingly, an object of the invention is to provide a sealing composition for a semiconductor excellent in a sealing property with respect to an interlayer dielectric layel; a semiconductor device in which the sealing composition for a semiconductor is used and a metliod of producing the sen~iconductodr evice, and a polymer suitable for the sealing composition for a semicoliductor and a ine:liood of produciiig the polymer. SOLUTION TO PROBLEM [0006] The inventors have conducted intensive investigations, and as a result tliereof, have found out that a sealing property with respect to an interlayer dielectric layer is significantly iniproved by adjusting the branching degree in a specific polymer to a certain value or higher, thereby completing the invention. In other words, the concrete means for solving the problems is as follows. [0007] A sealing composition for a semiconductol; comprising a polymer that includes two or more cationic functional groups including at least one of a tertiary nitrogen atom or a quaternary nitrogen atom, that has a weight average ~nolecularw eight of from 2,000 to 1,000,000, and that has a branching degree of 48% or more, wherein a content of sodium and a content of potassiun~ in the sealing composition are each 10 ppb by weight or 2 less on an element basis. Q> The sealing composition for a semiconductor according to , wherein the polymer includes a structural unit that is derived from an alkyleneimine having from 2 to 8 carbon atoms and that includes a tertiary nitrogen atom as a cationic fi~nctionagl roup. <3> The sealing composition for a semiconductor according to a>w,h erein the polymer filrtller includes a structural unit that is derived from an alkyleneimine having from 2 to 8 carboll atoms and that includes a secondary nitrogen atom as a cationic functional group. [0008] <4> The composition for sealing a semiconductor according to any one of <1> to <3>, wherein the polymer includes primary nitrogen atoms, and a proportion of the primary nitrogen aton~tso all the nitrogen atoms in the polymer is 33% by mole or more. <5> The sealing composition for a semiconductor according to any one of to <4>, wherein the branching degree of the polymer is 55% or more. 6 The sealing composition for a semiconductor according to any one of <1> to <5>, wherein the sealing composition has an average particle diameter measured by a dynamic light scattering method of 150 nm or less. <7> The sealing composition for a semiconductor according to any one of <1> to <6>, wherein the polymer is a polyethyleneimine or a derivative of a polyethyleneimine. <8> The sealing composition for a semiconductor according to any one of <1> to <7>, wherein the polymer has a cationic functional group equivalent of from 27 to 430. [0009] <9> Amethod of producing a semiconductor device, comprising a sealing composition application process of applying the sealing composition for a semiconductor according to any one of <1> to <8> to an interlayer dielectric layer formed on a mbstrate. The method of producing a semiconductor device according to <9>, wherein the interlayer dielectric layer includes a porous silica and has a silanol residue derived from the porous silica on a surface thereof. i l l > The method of producing a senliconductor device according to <9> or , the method further comprising a process of forming a concave groove having a width of from 10 nnl to 32 nm in the interlayer dielectric layel; wherein the sealing con~position application process includes bringing the sealing conlposition for a semiconductor into contact with the interlayer dielectric layer at at least a side surface of the concave groove. <12> A semicollductor device comprising a structure in which: an interlayer dielectric layer; a polymer layer containing a polymer that includes two or more cationic functional groups including at least one of a tertiary nitrogen atom or a quaternary nitrogen atom, that 3 has a weight average molecular weight of from 2,000 to 1,000,000, and that has a branching degree of 48% or more; and a layer including copper are disposed in this order. In the semiconductor device according to <12>, it is preferable that a copper barrier layer is further disposed between the polymer layer and the layer including coppee In addition, in the sen~iconductord evice according to <12>, the interlayer dielectric layer is preferably a porous interlayer dielectric layer (that is, an interlayer dielectric layer having a porous structure). [OOIO] <13> A polymer that con~prisestw o or more cationic functional groups including at least one of a tertiary nitrogen atoll1 or a quaternary nitrogen atom, that has a weight average n~olecularw eight of from 2,000 to 1,000,000, and that has a branching degree of 48% or more. <14> The polymer according to <13>, wherein the polymer is a polyethyleneimine or a derivative of a polyethyleneitnine. <15> Aniethod of producing the polymer according to <13> or <14>, the method comprising a process of reacting a raw material polymer containing a secondary nitrogen atom with a conlpound represented by the following Formula (m-1): [OOll] [0012] wherein, in Formula (m-1), R represents a protective group, and n represents an integer from 1 to 4. ADVANTAGEOUS EFFECTS OF INVENTION [0013] According to the invention, it is possible to provide a sealing composition for a se~lliconductore xcellent in a sealing property with respect to an interlayer dielectric layer, a semiconductor device in which the sealing cornposition for a semicor~ductoris used and a method of producing the se~lliconductord evice, and a polymer suitable for the sealing co~l~positiofonr a semiconductor and a method of producing the polymer. BRIEF DESCRIPTION OF DRAWINGS [0014] Fig. 1 is isothermal lines of toluene gas adsorption and desorption in Exarlples 1 and 2 and Comparative Examples 1 to 4. 4 Fig. 2 is isothermal lines of toluene gas adsorption and desorption in Examples 3 and 4 and Comparative Example 5. Fig. 3 is isothernlal lines of toluene gas adsorption and desorption in Example 5 and Comparative Example 6. Fig. 4 is isothermal lines of toluene gas adsorption and desorption in Example 6 and Comparative Example 5. DESCRIPTION OF EMBODIMENTS [0015] The sealing composition for a senliconductor of the invention is used, for example, to form a polymer layer covering the surface of an interlayer dielectric layer (preferably, a polymer layer covering the pores formed on a porous interlayer dielectric layer), and includes a polyn~er including two or more cationic functional groups including at least one of a tertiary nitrogen atom or a quaternary nitrogen atom, having a weight average molecular weight of from 2,000 to 1,000,000, and having a branching degree of 48% or more. The content of sodium and the content of potassiuln in the composition are each 10 ppb by weight or less on an element basis. I f the sealing composition for a semiconductor of the constitution is applied to an interlayer dielectric layer, two or more cationic functional groups contained in the polymer are nlultipoint adsorbed on the interlayer dielectric layer. Hence, the surface (pores present on the porous interlayer dielectric layer in a case in which the interlayer dielectric layer is a porous interlayer dielectric layer) of the interlayer dielectric layer is covered with a polymer layer. By viri-ee of this, ihe diffusion of a metal conlponent or a plasma colnponent into an interlayer dielectric layer (particularly, a porous interlayer dielectric layer) can be suppressed (that is, excellent sealing property is exerted with respect to an interlayer dielectric layer). Moreover, since a polynler layer formed by the polymer is a thin layer (for example, 5 nln or less), adhesion between an interlayer dielectric layer and a wiring material fornled on an interlayer dielectric layer via a polymer layer is excellent, and change in relative dielectric constant can be suppressed. [0016] Palticularly, in the sealing conlposition for a semiconductor of the invention, the two or Inore cationic functional groups includes at least one of a tertiary nitrogen atoll1 or a quaternary nitrogen atom, and the branching degree of the polylner is 48% or more, and thus remarkably excellent sealing property is exhibited with respect to an interlayer dielectric layer (pa~-ticularlya, porous interlayer dielectric layer). In other words, the diffusion of a metal, colllponent or a plasma component into an interlayer dielectric layer 5 (particularly, a porous interlayer dielectric layer) can be significantly suppressed. The reason for this is not clear, but it is presumed that if the branching degree of the polymer is high, the molecular chains having a branch st~ucturea re entangled with one another and thus the aperture between tlie molecular chains becomes small, and therefore, it can be efficiently prevented that a metal component or a plasma component passes through between the molecular chains. [0017] Furthermore, in the sealing composition for a semiconductor of the invention, the two or rnore cationic functional groups contains at least one of a tertiary nitrogen atom or a quaternary nitrogen atom, and the branching degree of the polymer is 48% or more. Hence, the excellent sealing property of tlie composition with respect to an interlayer dielectric layer is preserved even in a case in which the composition is applied to an interlayer dielectric layer and then subjected to a heat treatment (for example, a heat treatment at from 200°C to 425OC (preferably from 200°C to 400°C and more preferably from 200°C to 35OoC)). In other words, according to the sealing composition for a semicotiductor of the invention, a polymer layer (sealing layer) excellent in heat resistance can be formed on an interlayer dielectric layer. The reason for this is not clear, but it is presumed that tlie branching degree of the polymer is high, that is, the polymer is bulky, and thus thermal decomposition of the polytiier and deterioration in sealing property due to tlie thermal decomposition are suppressed. [0018] [Polymer] The sealing conlposition for a semiconductor of tlie invention contains at least one kind of polymer (hereinaftel; it is also referred to as the "poiymer of the invention") including two or more cationic functional groups including at least one of a tertiary nitrogen atom or a quaternary nitrogen atom, having a weight average n~oleculawr eight of from 2,000 to 1,000,000, and having a branchingdegree of 48% or more. [0019] In the invention, the term "branching degree" denotes a value obtained by tlie following Equation 1. Branching degree (%) = ((number of tertiary nitrogen atom +number of quaternary nitrogen atorn)/(number of secondary nitrogen atom + number of tertiary nitrogen atom + tiunlber of quaternary nitrogen atom)) x 100 ... Equation 1 Accordingly, for example, in a case in which the polymer of the invention is a polyalkyleneimine, a linear polyalkylenei~nined oes not include any tertiary nitrogen atom or quaternary nitrogen atom, and thus the linear polyalkyleneimine is a polyalkyle~ieiniine having a branching degree of 0%, and a polyalkyleneimine in which all the nitrogen atoms 6 contained in the backbone moiety except the terminals are tertiary nitrogen atoms (that is, it is maximally branched) is a polyalkyleneimine having a branching degree of 100%. [0020] In the invention, the term "primary nitrogen atom" denotes a nitrogen atom bonded only to two hydrogen atoms and one atom other than a hydrogen atom (for example, the nitrogen atom contained in a primary amino group (-NH2 group)), or a nitrogen atom (cation) bonded only to thee hydrogen atoms and one atom other than a hydrogen atom. In addition, the term "secondary nitrogen atorn" denotes a nitrogen atom bonded only to one hydrogen atom and two atoms other than a hydrogen atom (for example, the nitrogen atom contained in the functional group represented by the following Formula (a)), or a nitrogen atom (cation) bonded only to two hydrogen atoms and two atoms other than a hydrogen atotn. In addition, the term "tei-tiaiy nitrogen atotn" denotes a nitrogen atom bonded only to thee atoms other than a hydrogen atom (that is, the nitrogen atom of the functional group represented by the following Formula (b)), or a nitrogen atom (cation) bonded only to one hydrogen atom and thee atoms other than a hydrogen atom. In addition, the term "quaternary nitrogen atom" denotes a nitrogen atom (cation) bonded only to four atoms other than a hydrogen atom. In the description above, the "atom other than a hydrogen atom" is not particularly limited and may be, for example, a carbon atom, a silicon atom, or the like, and a carbon atom is preferable. [0021] [0022] In Forinulas (a) and (b), * represents a bonding position with an atom otl~etrh an a hydrogen atom. Here, the functional group represented by Formula (a) may be a functional group constituting part of a secoildary amino group (-NHRa group; here, represents an alkyl group), or a divalent li~lkingg roup contained in the backbone of a polymer, In addition, the functional group (that is, a tertiary nitrogen atom) represented by Forinula (b) may be a functional group coilstituting part of a tertiary amino group (-NR~R' group; here, Rb and Rc each independently represent an alkyi group), or a trivalent linking group contained in the backbone of a polymer. [0023] The branching degree of the polymer is required to be 48% or more. From the viewpoint of improving the sealing property, the branching degree is preferably 55% or 7 more, more preferably 70% or more, and particularly preferably 75% or more. The upper limit of the branching degree of the polymer is not paiTicularly limited, and the branching degree is less than 100% in a case in which the polymer contains a secondary nitrogen atom. The branching degree of the poly~neris preferably 95% or less from the viewpoint of easiness of synthesis. [0024] The method of adjusting the branching degree to 48% or more is not particularly limited. For example, there is a method in which the branching degree is adjusted by the polymerization condition of monomer itself when a polymer is synthesized, or a method in which a primary nitrogen atom or a secondary nitrogen atom contained in a polymer is reacted with another nitrogen-containing compound or an alkyl compound, and thus a tertiary nitrogen atom or a quaternary nitrogen atom is generated from the primary nitrogen atom or the secondary nitrogen atom, thereby increasing the branching degree. A concrete example of the latter method will be described as a "method of producing a polymer" below. [0025] In addition, the polyiner of the invention preferably includes a structural unit including a cationic functional group (a structural unit derived fkom a monomer including a cationic functional group). In this case, the structure of the polymer may be a structure formed by the polymerization of a monomer including a cationic functional group in a linear shape, or a structure formed by the polymerization of a monomer including a cationic firnctional group in a branched shape. [0026] The "cationic fiinctional group" in the invention is not particularly limited as long as it is a fi~nctionagl roup capable of being positively charged. As the cationic ftinctional grmp, a filnctional grmp containing a niirogen atom (a primary nitrogen atom, a secondary nitrogen atom, a tertiary nitrogen atom, or a quaternary nitrogen atom) is preferable. Here, the "fimctional group containing a nitrogen atom" may also be a functional group constituted by only one nitrogen atom. [0027] The polyiner of the invention includes two or more cationic functional groups including at least one of a tertiary nitrogen atom or a quaternary nitrogen atom. In the invention, a polymer including two or Inore cationic functional groups including at least one of a tertiary nitrogen atom or a quateinary nitrogen atom means a polymer including two or more cationic functional groups that include at least one of a tertiary nitrogen atom or a quaternary nitrogen atom as a cationic functional group (that is, a polymer including two or more cationic functional groups in which at least one of the two or more cationic functional groups is at least one of a tertiary nitrogen atom or a quateinary nitrogen atom). 8 The polymer of the invention is preferably a polymer including two or more of at least one of a tertiary nitrogen atom or a quaternaly nitrogen atom (particularly preferably a tertiary nitrogen atom) as a cationic functional group. [0028] The polymer of the invention nlay include primary nitrogen atoms or secondary nitrogen atoms as a cationic fi~nctionagl roup. In a case in which the polymer of the invention contains primary nitrogen atoms, the propol-tion of the primary nitrogen atoms to all the nitrogen atoms in the polymer is preferably 33% by mole or more. If the polymer of the invention contains primary nitrogen atoms (particularly, if the percentage of primary nitrogen atoms is 33% by Inole or more), the wettability between the polymer and the interlayer dielectric layer is more improved and the unifornrity of the thickness of the polymer layer is more improved, and thus the sealing property can be more inrproved. In addition, in a case in which the polymer contains primary nitrogen atoms, it is preferable that nitrogen atoms other than primary nitrogen atoms, such as secondary nitrogen atoms, coexist with the primary nitrogen atoms. By virtue of this, the thickness of the polylner layer is easily adjusted to an appropriate range, and the sealing property can be fin-ther improved. [0029] In addition, the polynler may further include an anionic functional group or a nonionic functional group if necessary. The nonionic fi~nctionagl roup nlay be a hydrogen bond receptor or a hydrogen bond donor. Exanrples of the nonionic functional group may include a hydroxyl group, a carbonyl group, and an ether group (-0-). The anionic fi~rictioaa:g roup is not pariicularly linliied as long as it is a fi~nciional group capable of being negatively charged. Examples of the anionic functional group may include a carboxylic acid group, a sulfonic acid group, and a sulfuric acid group. [0030] The polymer is a polymer including two or more cationic functional groups including at least one of a tertiary nitrogen atom or a quaternary nitrogen atom in one molecule. Apolynler having a high cation density is preferable from the viewpoint of fi~rtherim proving the sealing property. Specifically, a cationic functional group equivalent is preferably from 27 to 430 and more preferably from 43 to 200. Moreover, in a case in which the surface of an interlayer dielectric layer is hydrophobic treated by a publicly known method, for example, a method described in WO 041026765, WO 061025501, or the like, the cationic functional group equivalent is also preferably frorn 43 to 200 since the polar group density on the surface decreases. The cationic fi~nctionagl roup equivalent herein means a weight average molecular 9 weight per cationic functional group, and is a value (Mwln) obtained by dividing the weight average molecular weight (Mw) of a polymer by the number (n) of a cationic functional group contained in the polymer corresponding to one molecule. The density of cationic fi~nctionagl roup is low as this cationic fi~nctiouagl roup equivalent is large, and the density of.cationic fi~nctionagl roup is high as this cationic functional group equivalent is small. [003 11 In a case in which the polymer of the invention includes a structural unit (hereinafter, it is referred to as a "specific stl~~cturuanli t" in some cases) including a cationic functional group, the cationic functional group may be contained as at least part of the main chain, as at least part of a side chain, or as at least part of the main chain and at least part of a side chain in the specific structural unit. Moreover, in a case in which the specific structural unit includes two or more catiouic fi~nctionagl roups, the two or more cationic functional groups may be the same as or different from each other. In addition, the cationic functional group is contained such that the ratio (hereinafter, it is referred to as a "relative distance between cationic functional groups" in some cases) of the main chain length of the specific structural unit with respect to the average distance between the adsorption points (for example, a silanol residue) of the cationic futlctional groups present on the interlayer dielectric layer is preferably 1.6 or less and more preferably from 0.08 to 1 .O. By virtue of this aspect, the polyrner is more efficiently multipoint adsorbed on the interlayer dielectric layer. [0032] The tnolecular weight of the specific structural unit is preferably from 30 to 500 and more preferably from 40 to 200 from the viewpoint of adsorptivity to the interlayer dieiectric iayer. Meanwhile, the lllolecuiar weight of the specific structural unit means the molecular weight of a moliomer constituting the specific structural unit. The specific structural unit in the invention preferably has a relative distance between the cationic filnctiotlal groups of 1.6 or less and a molecular weight of from 30 to 500, and more preferably has a relative distance between the cationic functional groups of fro111 0.08 to 1.0 and a n~olecularw eight of from 40 to 200 from the viewpoint of adsorptivity to an interlayer dielectric layel: [0033] The specific structural unit (a structural unit including a cationic functional group) may be, specifically, the unit structure derived from a monomer containing a cationic functional group exemplified below. Specific exa~llpleso f the Inonomer containing a cationic fi~nctionagl roup include an alkyleneimine, allylamine, diall~~ldimethylarn~~~soanlti,u v~ilnly lpyridine, lysine, mnethyl vinylpyridine, and p-vinylpyridine. 10 [0034] The alkyleneimine is preferably an alkyleneimine having from 2 to 12 carbon atoms and tnore preferably an alkyleneimine having from 2 to 8 carbon atoms. In addition, the alkyleneimine having from 2 to 12 carbon atoms is preferably a substituted or unsubstituted cyclic alnine having from 2 to 8 carbon atoms. Specific examples of the alkylenei~nineh aving from 2 to 12 carbon atoms include ethyleneimine (another name: aziridine), propyleneimine (another name: 2-methyl aziridine), butyleneimine, pentyleneimine, hexyleneitnine, heptyleneimine, octyleneitnine, trimethyleneiniilie (another name: azetidine), tetramethyleneimine (another name: pyrrolidine), pentamethyleneimine (another name: piperidine), Iiexaniethylenein~inea, nd octamethyleneimine. Among them, etli~~lenein~iisn pea rticularly preferable. [0035] The monomer containing a cationic fi~nctionagl roup is, among them described above, preferably at least one of an alkyleneimine (preferably an alkyleneimine having from 2 to 8 carbon atoms) or an allylamine, and more preferably an alkyleneimine (preferably an alkyleneimine having from 2 to 4 carbon atoms, particularly preferably ethyleneimine) from the viewpoints of adsorptivity to an interlayer dielectric layer and sealing property. [0036] In addition, the polymer of the invention preferably contains a structural unit that is derived from an alkyleneimine having from 2 to 8 carbon atoms (more preferably having from 2 to 4 carbon atoms) and that contains a tertiary nitrogen atom, as the specific stsuctural unit (the structural unit containing a cationic functional group), from the viewpoints of adsorptivity to an interlayer dielectric layer and sealing property. The polymer of the invention more preferably contains a structural unit that is derived from an alkylenei~nineh aving from 2 to 8 carbon atoms (more preferably having fsom 2 to 4 carbon atoms) and that coniains a secondary nitrogen atom, in addition to the "structural unit that is derived from an alkyleneimine having fro1112 to 8 carbon atoms (more preferably having from 2 to 4 carbon atoms) and that contains a tertiary nitrogen atom", from the viewpoint of easiness of synthesis. [0037] In addition, in a case in which a cationic functional group is introduced into the polymer by reacting at least one of a primary nitrogen atom or a secondary nitrogen atom contained in a polynier with a nitrogen-containing compound in order to increase the branching degree, a cationic fi~nctionalg roup ("*" represents a bonding position with a nitrogen atom in the polymer backbone) represented below, or an alninopropyl group, a diarninopropyl group, an aminobutyl group, a diaminobutyl group, and a triaminobutyl group may be exemplified as a cationic functional group introduced into a polylner. [0038] [0039] Among the cationic functional groups introduced into a polymer, an amitloethyl group is preferable from the viewpoints of decreasing a cationic functional group equivalent and increasing a cationic functional group density. [0040] 111 addition, the polymer tnay further contain at least one kind of a unit structure containing a lionionic functional group or a unit structnre containing an anionic functional group. Specific examples of the ucit structure containing a nonionic functional group nlay include a unit structure derived fro111 a vinyl alcohol, a unit structure derived from an alkylene oxide, and a unit structure derived from vinylpyrrolidone. [0041] Moreover, specific examples of the unit stl~icturec ontaining an anionic functional group may include a unit structure derived froni styrenesulfonic acid, a unit structure derived from vinylslsulfiiric acid, a unit structure derived from acrylic acid, a unit structure derived from methacrylic acid, a unit structure derived from maleic acid, and a unit structure derived from fumaric acid. [0042] In a case in which the polymer contains two or more kinds of specific structural units in the invention, the specific structural units nlay be different from each other in terms of any of the kind or the number of the contained catiotiic functional group, the molecular weight, and the like. In addition, the two or nlore kinds of specific structural units may be contained as a block copolymer or a random copolymer. 12 [0043] In addition, the polymer may further contain at least one kind of stn~cturaul nit (hereinaftel; it is referred to as a "second structural unit" in some cases) other than the specific stlx~cturaul nit described above. In a case in which the polynler contains a second structural unit, the polymer may be a block copolymer containing the specific structural unit and the second structural unit or a random copolymer containing the specific structural unit and the second structural unit. The second structural unit is not particularly limited as long as it is a structural unit derived from a monomer capable of being polymerized with a monomer constitutilig the specific structural unit. Examples thereof may include a structural unit derived from an olefin. [0044] In addition, in a case in which the polylner of the invention is a polymer that does not include a particular structural unit but includes a random structure formed by polymerizing a monomer constituting a polymer in a branched mannel; the cationic functional group may be contained as at least part of the main chain, as at least part of a side cliaiti, or as at least part of the main chain and at least part of a side chain. [0045] Specific examples of the polymer of the invention may include a polyalkyleneimine (for exalnple, a polyalkyleneimine that is a polymer of an aikyleneitnine having fro111 2 to 12 carbon atoms (preferably having from 2 to 8 carbon atoms and more preferably having from 2 to 4 carbon atoms), particularly preferably polyethyleneimine (PEI)), polyallylamine (PAA), polydiallyl dimethyl ammonium (PDDA), polyvinyl pyridine (PVP), poly-lysine, polynletl~ypl yridyl vinyl (PMPyV), protonated poly(p-pyridyl vinylene) (R-PHPyV), and any derivative thereof. Among them, a polyalkyleneimine (for exanlple, a polyalkyleneimine that is a polylner of an alkylenei~~lithlaev ing from 2 to 12 carbon atoms (preferably having from 2 to 8 carbon atoms and more preferably having from 2 to 4 carbon atoms), particularly preferably polyethyleneinline (PEI)) or any derivative thereof, polyallylari~ine( PAA), and the like are preferable, and a polyalkyleneimine (for example, a polyalkyleneilnine that is a polymer of an alkyleneimine having from 2 to 12 carbon atonls (preferably having from 2 to 8 carbon atoms and more preferably having from 2 to 4 carbon atoms), particularly preferably polyethyleneimine (PEI)) or any derivative thereof is more preferable. [0046] Polyethyleneimine (PEI) can be generally produced by polymerizing etllyleneimine by a co~ntnonlyu sed method. The polyrnerizatioll catalyst, polyn~erizationc onditions, and the like can also be appropriately selected from those used commonly in the polymerization of ethyleneimine. Specifically, ethylelleimine is subjected to a reaction, for example, at from 0 to 200°C in the presence of an effective quantity of acid catalyst, for example, 13 hydrochloric acid. Moreover, ethylenei~ninem ay be addition polymerized to a base polyethyleneimine. In addition, polyethylenei~ninein the invention may be a ho~nopolynlero f ethyleneimine or a copoly~nero f ethyleneimine and a compound copolymerizable with ethyleneimine, for example, an amine. The production method of such a polyetl~yleneiminem ay be referred to in, for exanlple, Japanese Patent Publication (JP-B) No. S43-8828, JP-B No. S49-33120, and the like. In addition, polyethyleneimine described above may be polyethyleneimine obtained using crude ethyleneimine obtained from monoethanolamine. Specific description thereon may be referred to in, for example, JP-ANo. 2001-2123958, and the like. Meanwhile, a polyalkylenei~nineo ther than polyethyleneimine can be produced by the same method as polyethyleneimine. [0047] Polyethyleneimine produced by the method described above includes a complicated backbone including not only a partial structure in which ethyleneimine is ring opened and bonded in a linear shape, but also a partial structure in which ethyleneimine is ring opened and bonded in a branched shape, a partial st~~~ctiun rweh ich the partial structures in a linear shape are cross-linked with each other, and the like. A polyalkyleneimine other than polyethyleneimine also has a similar structure to polyethyleneimine. A polymer is more efficiently multipoint adsorbed by using a polymer including a cationic functional group of the structure described above. Moreovel; a covering layer is more effectively formed by the interaction between polymers. LO0481 Tine poiymer of the invention is aiso preferabiy a derivative of poiyai~yleneimine (for example, a derivative of polyalkyleneimine that is a polymer of an alkyleneimine having from 2 to 12 carbon atoms (preferably having from 2 to 8 carbon atoms and more preferably having from 2 to 4 carbon atoms), particularly preferably a derivative of polyethyleneimine). The derivative of polyalkyleneimine is not particularly limited as long as it is a compound producible using the polyalkyleneiinine described above. Specific examples thereof may include a derivative of polyalkyleneimine in which an alkyl group (preferably an alkyl group having from 1 to 10 carbon atoms) or an aryl group is introduced into a polyalkj~le~ieimillaen, d a derivative of polyalkyleneimine obtained by introducing a cross-linkable group such as a hydroxyl group into a polyalkyleneimine. These derivatives of polyalkyleneimine can be produced by a method performed conlmonly using the polyalkyleneimine described above. Specifically, these derivatives of polyalkyleneimine can be produced based 011 the method described in, for example, JP-A 14 No. H6-016809, or the like. [0049] In addition, as a derivative of polyalkyleneimine, a highly branched type polyalkyleneiniine obtained by increasing the branching degree of a polyalkyleneimine by reacting the polyalkyleneimine with a cationic functional group-containing monomer is also preferable. Examples of the method of obtaining a highly branched type polyalkyleneimine include a method in which a polyalkyleneimine including plural secondary nitrogen atoms in the backbone is reacted with a cationic functional group-containing monomer and tlrus at least part of the plural secondary nitrogen atoms are substituted with the cationic functional group-containing monomer, and a method in which a polyalkyleneimine including plural primary nitrogen atoms at terminals is reacted with a cationic functional group-containing monomer and thus at least part of the plural primary nitrogen atoms are substituted with the cationic fknctional group-containing monomer Examples of the cationic functional group introduced in order to increase the branching degree may include an aminoethyl group, an aminopropyl group, a diaminopropyl group, an aminobutyl group, a diaminobutyl group, and a triaminobutyl group, and an aminoethyl group is preferable from the viewpoint of decreasing the cationic functional group equivalent and increasing the cationic functional group density. As the method of obtaining a highly branched type polyalkyleneimine, a method explained in the section for a "method of producing a polymer'' to be described below can be used. [0050] Moreovel; polyethyleneimiue described above and any derivative thereof may be a conlmercially avaiiable product. For exan~piep, oiyeihyleneimine and any derivative thereof sold by NIPPON SHOKUBAI CO., LTD., BASF Japan Ltd., and the like may also be appropriately selected and used. [0051] The weight average lnolecular weight of the polymer in the invention is from 2,000 to 1,000,000, preferably from 2,000 to 600,000, preferably fronl 10,000 to 200,000, further preferably from 20,000 to 200,000, and more preferably from 20,000 to 150,000. For example, in a case in which the sealing composition for a semiconductor of the invention is applied to the production of a semiconductor device having a wiring interval of 32 nm or less and a pore diameter 011 the interlayer dielectric layer of about from 2 to 6 nm, if the weight average molecular weight of the polymer is more than 1,000,000, the size of the polymer is greater than the wiring interval, and thus the polyr~lerd oes not enter into a concave groove in which the wiring ~nateriails to be embedded, and as a result, a pore of a side surface of the groove is not sufficiently covered in some cases. In addition, if the 15 weight average molecular weight of the polyn~er is less than 2,000, the size of the polymer n~oleculeis smaller than the pore diameter on the interlayer dielectric layel; and thus the polymer molecule enters into the pore on the interlayer dielectric layer, and as a result, the dielectric constant of the interlayer dielectric layer increases in some cases. In addition, i f the weight average molecular weight of the polymer is less than 2,000, the polymer does not multipoint adsorb in some cases. Meanwhile, the weight average molecular weight is measured using a GPC device used colnmonly in the nlolecular weight ~neasuremento f polymer. [0052] In addition, the polymer is also preferably a polymer, of which the critical micelle concentration in a water medium is 1% by weight or more, or by which a micelle structure is not practically formed. Here, the description that a micelle structure is not practically formed indicates that a tnicelle is not formed under a common condition such as in a water medium of room temperature, that is, the critical micelle concentration cannot be measured. By a polymer having such a feature, a thin polymer layer (for example, 5 nm or less) having a thickness of lnolecular level is more effectively formed, and increase in the dielectric constant of interlayer dielectric layer can be more effectively suppressed. Furthermore, the adhesion between an interlayer dielectric layer and a wiring material is more effectively improved. [0053] Moreover, the polymer of the invention is preferably polyethyleneimine having a weight average nlolecular weight of from 2,000 to 1,000,000 and a cationic functional group equivalent of from 27 to 430, more preferably polyethyleneimine having a weight average tnolecnlar weight of from 2,000 to 600,000 and a cationic fi~nctional group equivalent of from 27 to 430, and particularly preferabiy poiyethyleneillline having a weight average molecular weight of from 10,000 to 150,000 and a cationic functional group equivalent of from 27 to 400. By virtue of this aspect, the diffilsion of a metal component or a plasma coniponent into an interlayer dielectric layer is more effectively suppressed and the adhesion between an interlayer dielectric layer and a wiring material is more improved. [0054] The content of the polymer in the sealing composition for a semiconductor of the invention is not particularly limited, and can be, for example, from 0.01% to 5.0% by weight and preferably from 0.02% to 0.3% by weight. In addition, the content of the polymller in the sealing composition can be also adjusted based on the area of a surface, on which a polymer layer is formed using the sealing composition for a semiconductor of the invention, and a pore density. [0055] [Method of Producing Polymer] As the method of producing a polynler of the invention, for example, a production 16 niethod including a process of reacting a raw material polynier containing at least one of a primary nitrogen atorn or a secondary nitrogen atom with a monomer including a cationic functional group is preferable. By the reaction described above, at least one of a tertiary nitrogen atom or a quaternary nitrogen atom is generated from at least one of the primary nitrogen atom or the secondary nitrogen atom included in the raw material polymer, and thus the polymer of the invention, which has a branching degree of 48% or more, can be suitably obtained. The reaction can be performed by mixing the raw material polytner with the ~nonomerin cluding a cationic functional group in a solvent such as water or an alcohol, and refluxing while heating. The reaction time can be appropriately adjusted, and is, for example, preferably from 1 to 24 hours and more preferably from 2 to 12 hours. [0056] The raw material polymer in the method described above is not particularly limited as long as it contains at least one of a pri~naryn itrogen atom or a secondaly nitrogen atom, and a raw material polymer containing a secondary nitrogen atom is preferable. Exa~npleso f the raw niaterial polymer containing a secondary nitrogen atom i~icludesa polyalkyleneirnine that is a polynier of an alkyleneimine having from 2 to 12 carbon atoms (preferably having from 2 to 8 carbon atoms), poly(N-alkylamide), or any derivative thereof. Here, specific examples of tlie alkyleneimine having from 2 to 12 carbon atoms are as described above. In addition, examples of the derivative include a polyalkyle~ieiminei nto which an anionic functional group has been introduced. [0057] The weight average molecular weight of the raw material polymer is not particularly limited as long as it is a weight average lnoiecular weight that enabies production of tlie polyrner of tlie invention having a weight average tnolecular weight of from 2,000 to 1,000,000 by a reaction with a n~ono~nienrc luding a cationic hnctional group. For exatnple, the weight average molecular weight of the raw material polymer is preferably fro111 1,000 to 500,000, Inore preferably from 2,000 to 200,000, and particularly preferably from 5,000 to 150,000. [0058] In addition, exa~npleso f the monomer including a cationic functional group used in the production neth hod described above include a nitrogen-containing compound. In addition, the cationic functional group in the ~nono~nienrc luding a cationic fi~nctionagl roup used in the production niethod described above is preferably bonded to a protective group that is stable under the reaction condition. By virtue of this, the reaction between the nionomers including a cationic 17 fi~nctionalg roup can be suppressed, and thus a polymer having a higher branching degree can be produced. [0059] As tlie protective group, a protective group used commonly can be used. Examples of the protective group include a t-butoxycarbonyl group (Boc group), a benzyloxycarbonyl group, a methoxycarbonyl group, a fluorenylcarbonyl group, a formyl group, an acetyl group, a benzoyl group, a phthaloyl group, an allyl group, and a benzyl group. [0060] As the monomer including a cationic functional group bonded to a protective group, a nitrogen-containing compound including a nitrogen atom bonded to a protective group is more preferable. Specific examples of the nitrogen-containing compound including a nitrogen atom bonded to a protective group include a co~npound represented by any one of the following Formulas (m-1) to (m-3). [0061] [0062] In Fornmlas (ni-1) to (ni-3), R represents a protective group, and n represents an integer from 1 to 4. Tlie protective group represented by R may be any functional group that is generally used as the protective group for a nitrogen atom, and, for exa~nplea, t-butoxycarbonyl group (Boc group), a benzyloxycarbonyl group, a methoxycarbonyl group, a fluorenylcarbonyl group, a formyl group, an acetyl group, a benzoyl group, a phthaloyl group, an allyl group, and a benzyl group are preferable. [0063] The nitrogen-containing compound (monomer) including a nitrogen atom bonded to a protective group is further preferably a compound represented by Formula (m-1), and particularly preferably a conlpound (protected aziridine) represented by Fornlula (m-1) in which 11 is 1. In addition, as the method of producing a poly~ner of the invention, a production neth hod including a process of reacting a raw nlaterial polymer (for example, a 18 polyalkyleneimine that is a polymer of an alkyleneirnine having from 2 to 12 carbon atoms) containing a secondary nitrogen atom with a conipound represented by Formula (m-1) is particularly preferable. [0064] In addition, the rnethod of producing a polymer rnay include another process such as a process of deprotecting a cationic fiinctional group including a protective group introduced into a polymer, if necessary. [0065] [Other Conlponents] A content of sodium and a content of potassium in the sealing composition for a semiconductor of the invention are each 10 ppb by weight or less on an element basis. If the content of sodium and the content of potassiun~a re each more than 10 ppb by weight on an element basis, a trouble in electrical properties of a se~niconductodr evice such as failure of transistor occurs in some cases. [0066] The sealing cornposition for a semiconductor of the invention can contain a solvent in addition to the polymer if necessary. The solvent in the invention is not particularly liniited as long as it is a solvent in which the polynler dissolves unifornlly and hardly forms a micelle. Examples of the solvent may include water (preferably ultrapure water) and a water soluble organic solvent (for example, an alcohol, or the like). In the invention, water or a nlixture of water and a water soluble organic solvent is preferably used as a solvent from the viewpoint of micelle forming property. [0067] In addition, the boiling point of tlie solvent is not particularly limited, but is preferably 210°C or lower and further preferably 160°C or lower. If the boiling point of solvent is in tlie above described range, the solvent can be removed at a temperature low enough not to significantly damage the dieiectric properties of the interlayer dielectric iayer and not to allow the sealing conlposition to be peeled off from the interlayer dielectric layer, for example in a case in which a cleaning process or a drying process is provided after a process in which the sealing co~npositionf or a semiconductor of the invention is brought into contact with an interlayer dielectric layer. [0068] Moreover, the sealing composition for a sen~iconductoro f the invention may further contain a cation such as a cesium ion if necessary in a range that does not impair the effect of the i~ivention. If a cation such as a cesiunl ion is contained in the conlposition, the polymer in tlie sealing composition for a semiconductor is prone to be more unifor~nly spread on the interlayer dielectric layer. [0069] Furthermore, it is preferable that the sealing co~npositionf or a serniconductor of the invention does not contain a compound that brings about corrosion or dissolution of the interlayer dielectric layer. Specifically, for example, if a fluorine compound or the like is 19 contained in the composition of the invention, the interlayer dielectric layer is dissolved, and thus the dielectric properties of the interlayer dielectric layer are damaged and relative dielectric constant thereof increases in some cases pai-ticularly in a case in which the main material of the interlayer dielectric layer is an inorganic compound such as silica. [0070] The sealing conlposition for a semiconductor of the invention preferably contains only a compound that has a boiling point of 210°C or lower and preferably 160°C or lower, or only a conlpound that does not exhibit degradability even heated up to 250°C, as a component other than the polymer. Meanwhile, the "compound that does not exhibit degradability even heated up to 250°C" is a compound of which the weight change after being held at 250°C under nitrogen for 1 hour is less than 50% with respect to the weight measured at 25OC. [0071] The sealing conlposition for a semiconductor of the invention preferably has an average particle diameter ineasured by a dynamic light scattering method of 150 nm or less. If the average particle diameter is 150 nm or less, adhesion with the wiring material is inore improved, and thus diffusion of a metal component or a plasma conlponent into an interlayer dielectric layer is further suppressed. The average particle diameter in the invention is measured by a dynamic light scattering method using ELSZ-2 manufactured by OTSUKA ELECTRONICS CO., LTD. and obtained as a cumulant average pai-ticle diameter. The measurement is performed under a condition of, for example, a solution concentration of fion~0 .1% to 1.0%, a temperature of from 23°C to 26"C, a cumulative number of 70 times, a repeat count of 3 times, and the like. A stable measurement can be performed by adding an electrolyte such as NaCl if necessary. [0072] Meanwhile, the case in which the average particle diameter is more than 150 nm in the invention is specifically a case in which a micelle (a micelle having an average particle diameter of more than 150 nm) is fornled in the conlposition, a case in which a polishing grain such as a metal oxide, or the like used at the time of polishing (chemical mechanical polishing) copper to be a wire is contained in the composition, or the like. If a micelle having a large particle diameter is formed in the sealing composition for a semiconductor, a polymer constituting the sealing composition for a semiconductor cannot sufficiently enter into a concave groove in which a wiring material is to be embedded, and thus a pore on a side surface of the groove cannot be sufficiently covered in solne cases, for example, in a case in which the sealing con~positionfo r a semiconductor of the invention is applied to the production of a semiconductor device having a line width of 32 tun or less. 20 [0073] Tlie average particle diameter is preferably 100 nm or less, more preferably 50 nm or less, further more preferably 30 inn or less, and particularly preferably 10 mn or less fro111 the viewpoint that the adhesion with the wiring material is more improved and the diffusion of a metal component or a plasma component into an interlayer dielectric layer is further suppressed. [0074] The pH of the sealing composition for a semiconductor of the invention is not particularly limited, and tlie pH is preferably equal to or higher than an isoelectric point of an interlayer dielectric layer fro~nth e viewpoint of the adsorptivity of a polymer to the interlayer dielectric layer. In addition, the pH of the sealing composition for a semiconductor of the invention is preferably in a pH range in which the cationic functional group is in a cationic state. If the sealing composition for a senliconductor has the pH described above, the polymer is more efficiently adsorbed on an interlayer dielectric layer by the electrostatic interaction between the interlayer dielectric layer and the polymer. [0075] The isoelectric point of an interlayer dielectric layer is the isoelectric point exhibited by a conipound constituting the interlayer dielectric layel; and for example, in a case in which a compound constituting an interlayer dielectric layer is porous silica, the isoelectric point is near pH 2 (25°C). In addition, the pH range in which the cationic functional group is in a cationic state is such that the pH of the sealing conlposition for a semiconductor is equal to or less than the pKb of a polymer containing a cationic functional group. For example, in a case in which a polynier containing a cationic functional group is polyallylamine, the pKb is from 8 to 9, and in a case of polyethyleneinline, the pKb is from 7 to 12. In other words, the pH of tlie sealing composition for a semiconductor in the invention can be appropriately selected depending on the kind of the compound constituting an interlayer dielectric layer and the kind of tlie polymer, and the pH is, for example, preferably from 2 to 12 and more preferably from 7 to 11. Meanwhile, the pH (25°C) is measured using a pH measuring device used commonly. [0076] The method of producing a semiconductor device of the invention includes a sealing conlposition application process of applying tlie sealing composition for a semiconductor of the invention to an interlayer dielectric layer formed on a substrate, and further includes another process if necessary. The interlayer dielectric layer in tlie invention is preferably constituted by a material having a low dielectric constant. In addition, the interlayer dielectric layer in the 2 1 invention is preferably a porous interlayer dielectric layer (that is, an interlayer dielectric layer having a porous structure). The pore radius of the porous interlayer dielectric layer is not particularly limited, but is preferably fioni 0.5 tini to 4.0 nm and niore preferably fiom 1.0 nm to 3.0 nni from the viewpoint that the sealing property effect in the production method is more effectively exhibited. [0077] In addition, tlie interlayer dielectric layer preferably contains porous silica and has a silanol residue derived from porous silica on the surface. In this case, a thin layer of a polymer is fornled such that pores on the interlayer dielectric layer are covered with the polymer by the interaction of the silanol residue and a cationic functional group contained in the polymer. [0078] As the porous silica, a porous silica that is con~monlyu sed in an interlayer dielectric layer of se~niconductord evice can be used without particular limitation. Examples thereof may include an oxide having a uniform mesopore in which self-organization of an organic compound and an inorganic conlpound is used and which is Ilydrotliermally synthesized in a sealed heat resistant container using a surfactant and silica gel described in WO 9111 1390, or porous silica produced fiom a surfactant and a condensate of an alkoxysilane described in Nature, Vol. 379, p. 703, 1996 or Supramolecular Science, Vol. 5, p. 247, 1998. In addition, as the porous silica, porous silica (for example, porous silica formed using a co~npositionc ontaining a specific siloxane compound) described in WO 2009/123104 (Paragraphs from [0009] to [0187]) or WO 2010/137711 (Paragraphs from 100431 to [0088]) is preferably used. [0079] The substrate provided with an interlayer dielectric layer in the production method is not particularly limited, and examples thereof may include a semiconductor substrate such as silicon wafer, a glass substrate, a quartz substrate, a stainless substrate, and a plastic substrate. The shape of tlie substrate is also not pai-ticularly limited, and may be any shape such as a platy shape or a patelliform shape. [0080] The method of producing a seniicondnctor device of the invention includes a sealing coniposition application process of applying the sealing composition for a semiconductor of tlie invention to an interlayer dielectric layer fornied on a substrate. The method of applying the sealing composition for a se~niconductoro f the invention to the interlayer dielectric layer is not particularly limited, and a method used com~nonlyc an be used. For example, a dipping method (for example, see the specification of U.S. Patent No. 52081 1 I), a spraying method (for example, see Sclilenoff et al., Langmuir, 16 (26), p. 9968,2000 or Izquierdo et al., Langmuir, 21 (16), p. 7558,2005), a spin coating method (for exanlple, see Lee et al., Langmnnir, 19 (la), p. 7592, 2003 or J. Polymer Science, part B, polyrner physics, 42, p. 3654,2004), and the like can be used. [0081] The method of applying the sealing co~npositionfo r a sen~iconductorb y the spin coating method is not particularly limited, and for example, a method can be used in which a sealing co~npositionfo r a semiconductor is dropped on an interlayer dielectric layer while rotating a substrate on which the interlayer dielectric layer is formed by a spin coater, subsequently a rinsing treatment is perfornled by dropping a rinsing liquid such as water, and then drying is performed by increasing the revolution number of tlie substrate. At this time, dlying may be performed after dropping of the sealing composition for a semiconductor, and dropping of water are repeated plural times. Alternatively, a sealing coniposition for a se~niconductorm ay be dropped and then dried by increasing the number of revolutions, and after hying, the substrate may be temporarily transferred to a heat treatment device such as a hot plate and subjected to a heat treatment, and after heat treatment, the substrate may be reinstalled to the spin coater again, and then a rinsing treatment and drying may be performed (these operations described above may be repeated plural times). In the method of applying the sealing composition for a semiconductor by the spin coating method, conditions such as the revolution number of the substrate, the amount of the sealing composition for a semiconductor dropped and the dropping time thereof, the revolution number of substrate at the time of drying, and the amount of the rinsing liquid dropped and the dropping time thereof are not particularly limited, and can be appropriately adjusted in consideration of the thickness of a polymer layer (sealing layer) to be formed. [0082] In the method of producing a semiconductor device of the invention, a polymer layer containing the polymer can be formed on an interlayer dielectric layer as a thin layer using the sealing conlposition for a semiconductor containing the polymer. The thickness of the polymer layer is not particularly limited, and is, for example, from 0.3 nm to 30 nnl, preferably from 0.3 nnl to 10 nm, more preferably from 0.3 nm to 5 m, and particularly preferably from 0.5 ntn to 2 ilm. Meanwhile, examples of the poly~nerla yer stated herein include not only a form of a layer of polynler only but also a for11 of a layer (so-called infiltration layer) having a structure in which a poly~neris infiltrated into the pores of a porous interlayer dielectric layer, in a case that the interlayer dielectric layer is a porous interlayer dielectric layer. [0083] In tlie niethod of producing a se~niconductord evice of the invention, it is preferable that the sealing composition for a semiconductor contains a polymner having a cationic 23 functional group equivalent of from 27 to 430, and the pH of the sealing composition for a semiconductor is equal to or higlier than the isoelectric point of the interlayer dielectric layel; and the pH is in the range in which the cationic functional group is in a cationic state, and the pH is more preferably from 2 to 12, fui-ther preferably from 7 to 11. The polymer is more efficiently adsorbed to the interlayer dielectric layer by bringing the sealing composition for a semiconductor into contact with the interlayer dielectric layer. The isoelectric point of the interlayer dielectric layer and the pH range in which tlie cationic functional group is in a cationic state are as described above. [0084] Fui-tl~ert,h e concentration of the polymer contained in the sealing composition for a semicoliductor used in the sealing colnposition application process of the invention is preferably less than the critical rnicelle concentration of the polymer. By virtue of this, the polynler can be applied to the interlayer dielectric layer as a thin layer (for example, 5 nm or less and more preferably 2 ilm or less), and increase in dielectric constant can be suppressed. [0085] It is preferable that the method of producing a selniconductor device of the invention further includes a process of forming a collcave groove having a widtli of from 10 nm to 32 nu1 in the interlayer dielectric layer, and the sealing composition application process is a process of bringing the sealing composition for a semiconductor into contact with the interlayer dielectric layer at at least a side surface of the coiicave groove. By virtue of this aspect, the interlayer dielectric layer (pores present on an interlayer dielectric layer in a case in which this interlayer dielectric layer is a porous interlayer dielectric layer) constituting the side surface of the colicave groove formed in the interlayer dielectric layer can be effectively covered. The diffusion of a metal component constituting a wiring material into the interlayer dielectric layer can be suppressed in a case in which the wiring material is embedded in the concave groove. Meanwhile, the side surface of a concave groove means a surface formed so as to intersect approximately orthogonally with respect to the surface parallel to a substrate. [0086] The process of forlning a concave groove having a widtli of from 10 nm to 32 nm in the interlayer dielectric layer can be performed according to the commonly used production process conditions of a semiconductor device. For example, a hard mask and a pliotoresist are fornled on an interlayer dielectric layel; and etching is perforlned according to tlie pattern of the pliotoresist, whereby a groove having a desired pattern can be formed. [0087] In addition, as the method of briliging the sealing coiiiposition for a semiconductor into contact with the interlayer dielectric layer on a side surface of the concave groove, the dipping method, the spraying method, and the spill coating method described above call be 24 used. In the invention, a cleaning process or a drying process may be further provided if necessary after bringing the sealing composition for a semiconductor into contact with the interlayer dielectric layer. [0088] In the method of producing a semiconductor device of the invention, a process that is commonly performed, such as a wiring forming process, may be further included if necessaly after the sealing composition application process. The wiring forming process can be performed according to a publicly known process condition. For example, a copper wiring is formed by a metal CVD method, a sputtering method, or an electrolytic plating method, and the film is smoothed by CMP. Subsequently, a cap film is formed on the surface of the film. A hard mask is further fonned if necessary. A tnultilayer can be formed by repeating the processes described above, whereby the semiconductor device of the invention can be produced. [0089] Moreover, in the method of producing a semiconductor device of the invention, a barrier film (copper barrier layer) forming process can be further provided after the sealing composition application process but before the wiring forming process. The diffusion of metal component into the interlayer dielectric layer can be more effectively suppressed by forming a barrier film. The barrier film forming process can be perfornled according to a process condition used conlmonly. For example, a barrier film of a titanium cornpound such as titanium nitride, a tantalum compound such as tantalum nitride, a lutl~eniumc ompound, or a manganese compound can be formed by a vapor growth method (CVD) after the sealing composition application process. In the invention, a barrier film consisting of rut'henium compound is preferably formed. [0090] The semiconductor device of the invention includes a structure in which an interlayer dielectric layer (preferably a porous interlayer dielectric layer), a polymer layer containing a polymer including two or more cationic functional groups including at least one of a teltiary nitrogen atom or a quaternary nitrogen atom and having a weight average molecular weight of from 2,000 to 1,000,000, and a layer including copper are disposed in this ordel; and fi~rtherin cludes other layers if necessary. Since a polymer layer containing a specific polymer is disposed between the interlayer dielectric layer and the wiring material, the occurrence of leakage current or the like is suppressed even in a fine circuit constitution of 32 nm or less, and thus favorable characteristics can be exhibited. In the semiconductor device of the invention, the thickness of the polymer layer is 25 preferably from 0.3 nm to 5 nm. In addition, in the semiconductor device of the invention, it is preferable that a copper barrier layer (preferably, a layer of ruthenium compound) is further disposed between the polynier layer and the wiring material containing copper. Meanwhile, the semicondnctor device of the invention can be produced by the method of producing a semiconductor device. EXAMPLES [0091] Hereinafter, the invention will be described in more detail with reference to Examples, but the invention is not limited to these Examples. [0092] [Synthesis Example 11 (Syntliesis of Modified Polyethyleneimine 1) Modified polyethyleneimine 1 was synthesized according to the following Reaction scheme 1 using polyethyleneimine as a starting material. Meanwhile, tlie polymer structures in the following Reaction scheme 1 and Reaction scheme 2 are structures illustrated scliematically. The configuration of the tertiary nitrogen atom and the secondary nitrogen atom or the proportion of the secondary nitrogen atom to be substituted with a Boc-aminoethyl group to be described below changes in various ways by the synthesis condition. [0093] Reaction scheme 1 Boc' N H Boc' N H Boc' N H Boc: *'Of [0094] In Reaction schenle 1 above, * represents a bonding position. In this Synthesis Example 1, the detailed operation of Reaction sche~ne 1 above was as follows. In 70 mL of isopropanol, 10.5 g of polyethylenei~nine (50% aqueous solution) manufactured by MP Biomedicals, LLC. was dissolved, 17.5 g (122 mmol) of N-t-butoxycarbonyl (in Examples, t-butoxycarbonyl group is also referred to as "Boc") aziridine was added thereto, and the resultant was refluxed for 10 hours while heating, thereby obtaining modified polyethylenei~nine 1 having a structure in which a Boc-aminoetllyl group was introduced into polyethylenei~nine. It was confirmed that N-Boc aziridine of the raw nlaterial was not present by thin-layer chromatography (TLC). The solvent was concentrated under reduced pressure, and then the structure of the resultant was confirmed by 'H-NMR. The introduction rate of the Boc-arninoethyl group with respect to polyethyleneimine was calculated to be 95% from 'H-NMR data. 'H-NMR (CD30D): 6 3.3 - 3.0 (br. s, 2), 2.8 - 2.5 (BL s, 6.2), 1.45 (s, 9) [0095] (Synthesis of Hyperbranched Polyethylenein~ine 1 ) Hyperbranched polyethyleneimine 1 was synthesized according to the following Reaction scheme 2 using the nlodified polyethyleneimine 1 as the starting material. 27 [0096] Reaction scheme 2 Boc-NH Boc, f' f' CH30H HCl(aq.) - Boc' N H Boc' N H Boc' N H [0097] In this Synthesis Example 1, tlie detailed operation of Reaction scheme 2 above was as follows. The modified polyetliyleneimine 1 was dissolved in 40 mL of methanol, and 20 mL of 12N hydrochloric acid Jvas gradually added to this soh~tionw hile stirring the solution tl111s obtained. The solution thus obtained was stirred at 50°C for 4 hours while heating. Reaction product in the form of gun1 was geuerated in the reaction solution together with the generation of gas. The reactioli solutio~wi as cooled after generation of gas was conlpleted. After cooling, the solvent separated from this reaction product in the form of gum was removed, and then the remaining reaction product was washed with 10 mL of inethanol two times. The reaction product after washing was dissolved in water, and the chlorine ion was removed by an anion exchange polymer, thereby obtaining 8 g of liyperbranched polyetliyleneimine 1. 'H-NMR (D20): 6 2.8 - 2.4 (br. m) ' 3 ~(Dz-O): ~6 (int~egra~tiou r atio) 57.2 (1.0), 54.1 (0.38), 52.2 (2.26), 51.6 (0.27), 48.5 (0.07), 46.7 (0.37), 40.8 (0.19), 38.8 (1.06) [0098] With regard to the liyperbranched polyethyleneimine 1, the weight average molecular weight, the nlolecular weight distribution, the cationic fi~nctioaagl roup (a primary nitrogen atom, a secondary nitrogen atom, a tertiary nitrogen atom, and a quaternary nitrogen atom) equivalent, the amonnt (% by mole) of primary nitrogen atom, 28 the amount (% by mole) of secondary nitrogen atom, the amount (% by mole) of tertiary nitrogen atorn, the amount (% by mole) of quaternary nitrogen atom, the branching degree (%), and the viscosity q (dllg) were measured, respectively. The results of the measurements are listed in Table 1 to be described below. [0099] Here, the cationic functional group equivalent is a value of the molecular weight with respect to one cationic functional group, and can be calculated from the structure of polymer. In addition, the anlount (% by mole) of primary nitrogen atom, the amount (% by mole) of secondary nitrogen atom, the amount (% by mole) of tertiary nitrogen atom, the amount (% by mole) of quaternary nitrogen atom, and the branching degree (%) were calculated on the basis of the integrated value obtained as follows. A polymer sample (in this Synthesis Example 1, hyperbranclled polyethyleaeimine 1) was dissolved in heavy water, and I3c-~MRm easurement was perfonned by a single pulse reverse gated decoupling method at 80°C using AVANCE 500 type nuclear magnetic resonance apparatus manufactured by Bruker Japan Co., Ltd, with regard to the solution thus obtained, arid analysis on \1~11ich order of amine (nitrogen atom) each of the carbons was bonded to was performed from the result of I3c-~MRm easurement. Description on assignment is stated in European Polymer Journal, 1973, Vol. 9, pp. 559, and the like. The weight average molecular weight and the molecular weight distribution were measured using Shodex GPC-101 as an analytical instrument and Asahipak GF-7M HQ as a column, and calculated using polyetllylene glycol as the reference standard. However, since the standard curve of GPC changes as the branching degree increases as known by the Mark-Houwink-Sakurada equation, it should be noted that the weight average molecular weight and the molecular weight distribution in Table 1 are the numerical values based on polyetllylene glycol. [0100] Here, the anlount (% by mole) of primary nitrogen atom, the amount (% by mole) of secondary nitrogen atom, the amount (% by mole) of tertiary nitrogen atom, and the amount (% by mole) of quaternary nitrogen atom are the amounts represented by the following Equations A to D, respectively. [0101] Amount (% by mole) of primary nitrogen atom = (mole number of primary nitrogen atonll(mole number of primary nitrogen atom + mole number of secondary nitrogen atom + mole number of tertiary nitrogen atorn + mole number of quaternary nitrogen atorn)) x 100 ... Equation A Amount (% by mole) of secondary nitrogen atom = (mole number of secondary nitrogen atom/(nlole number of primary nitrogen atom + mole number of secondary 29 nitrogen atom + mole number of tertiary nitrogen atom + mole number of quaternary nitrogen atonl)) x 100 ... Equation B Amount (% by mole) of tertiary nitrogen atom = (mole number of tertiary nitrogen atom/(mole number of prinialy nitrogen atom + mole number of secondary nitrogen atom + mole number of tertiary nitrogen atom + nlole number of quaternary nitrogen atom)) x 100 ... Equation C An~oullt(% by mole) of quaternary nitrogen atom = (mole number of quaternary nitrogen atom/(mole number of primary nitrogen atom + mole number of secondary nitrogen atom +mole number of tertiary nitrogen atom + mole number of quaternary nitrogen atom)) x 100 ... Equation D [0102] In addition, the branching degree was obtained by the following Equation E. Branching degree (%) = ((amount (% by mole) of tertiary nitrogen atom + amount (% by mole) of quaternary nitrogen atom)/(amount (% by mole) of seconda~yn itrogen atom + amount (% by mole) of te~tiaryn itrogen atom + amount (% by mole) of quaternary nitrogen atom) x 100 ... Equation E [0103] In addition, viscosity q (dug) was obtained by measuring the sample solution drain time (seconds) and blank drain time (seconds) using Ubbelohde viscometer with regard to an aqueous solution containing 0.5% by weight of hyperbranched polyetliyleneimine 1 and then calculating by the following Equation F. Viscosity q (dl/g) = (In (sample solution drain time (seconds)/blank drain time (seconds)))/conce~itrationo f solution (g/dl) ... Equation F [0104] [Synthesis Example 21 (Synthesis of Modified Polyethyleneimine 2) Modified polyethyleneimine 2 was synthesized by tlie same reaction scheme as Reaction scheme 1 above. However, in this Synthesis Example 2, the detailed operation was as follows. In 64 lnL of isopropanol, 12.8 g of polyethyleneimine (50% aqueous solt~tion) manufactured by MP Biomedicals, LLC. was dissolved, 4.26 g (30 nlmol) of N-Boc aziridine is added thereto, and the resultant was refluxed for 3 hours while heating, thereby obtaining reaction liquid containing modified polyethyleneimine 2 having a structure in wliicli a Boc-aminoetliyl group was introduced into polyetliyleneimi~ie. It was confirmed that N-Boc aziridine of tlie raw material was not present by TLC. A small amount of the reaction liquid was taken as a salnple and then NMR measurement of the sample was perfol.nied, tliereby confirming the structure thereof. The introd~ictionra te of the 30 Boc-aminoethyl group with respect to polyethyleneimine was calculated to be 20% fsom 'H-NMR data. 'H-NMR (CD30D): 6 3.3 - 3.0 (br. S, 2), 2.8 - 2.5 (BL S, 23), 1.45 (s, 9) [0105] (Synthesis of Hyperbranched Polyethyleneimine 2) I-Iyperbranched polyethyleneimine 2 was synthesized by the same reaction scheme as Reaction scheme 2 above. However, in this Synthesis Example 2, the detailed operation was as follows. To this reaction liquid containing the modified polyethyleneimine 2, 14.9 mL of 12N hydrochloric acid was gradually added while stirri~lgth e reaction liquid. The solution thus obtained was stirred at 50°C for 3 hours while heating. Reaction product in the form of gum was generated in the reaction solutio~tlo gether with the generation of gas. The reaction solution was cooled after generation of gas was completed. After cooling, the solvent separated from this reaction product in the form of gum was removed, and then the remaining reaction product was washed with 10 mL of methanol three times. The reaction product a~ftewr ashing was dissolved it1 water, and the chlorine ion was removed by an anion exchange polymer, thereby obtaining 10.5 g of hyperbranched polyethyleneimine 2. 'H-NMR (D20): 6 2.8 - 2.4 (br. m) 13 C-NMR (D2O): 6 (integration ratio) 57.1 (1.0), 54.1 (1.61), 52.2 (2.75), 5 1.5 (0.82), 48.5 (1.07), 46.6 (1.67), 40.7 (0.79), 38.8 (1.04) [0106] With regard to the hyperbranched polyethyleneimi~le2 , the weight average molecular weight, the molecular weight distribution, the cationic functional group equivalent, the atnount (% by mole) of primary nitrogen atom, the amount (% by mole) of secondary nitrogen atom, the amoutlt (%by inole) of iertiary nitrogerl atom, the amount (% by mole) of quaternary nitrogen atom, the branching degree (%), and the viscosity q (dllg) were measured, respectively in the same manner as in the hyperbranched polyethyleneimine 1. The results of the eneasasumeuts are listed in Table 1 to be described below. [O 1071 [Sy~lthesisE xample 31 In 30 tnL of methanol, 10.0 g of polyethyleneimi~ieP -1000 (30% aqueous solution) ma~lufactured by NIPPON SHOKUBAI CO., LTD. was dissolved, and the solution tllus obtained was cooled to 10°C or lower. To the solutio~ai fter cooling, 6.0 g (70 mmol) of methyl acrylate was added dropwise, and then was left to stand at room temperature for 48 hours. Asmall amount of the solution after leaving to stand was taken as a sample, and then it was confirmed that methyl acrylate was not present by 'H-NMR ineasureme~~t. To the solutio~al fter leaving to stand, 83.7 g (1395 mmol) of ethylenediamine was added and 3 1 then refluxed for 9 hours while heating. The reaction solvent and excessive ethylenediamine were distilled off under reduced pressure from the solution after refluxing, and the residue was dissolved in 25 mL of methanol. Apolynier was precipitated by adding ethyl acetate to the solution thus obtained, aud then the solvent was removed, and the residue was washed with ethyl acetate. Water was added to tlie residue after washing, and then the resultant was concentrated under reduced pressure, thereby obtaining 8.55 g of hyperbranched polyethyleneimine 3. 'H-NMR (D20): 6 3.3 - 3.1 (bx s, l), 2.9 - 2.2 (BK 111, 6) [0108] With regard to the hyperbranched polyethyleneimine 3, the weight average niolecular weight, the molecular weight distribution, tlie cationic functional group equivalent, the amount (% by mole) of primary nitrogen atom, the amount (Oh by mole) of secondary nitrogen atom, the anlount (% by mole) of tertiary nitrogen atom, the amount (Oh by mole) of quaternary nitrogen atom, the branching degree (%), and the viscosity q (dllg) were measured, respectively in the same manner as in the hyperbranched polyethyleneimine 1. The results of tlie measurenients are listed in Table 1 to be described below. [0109] [Synthesis Example 41 Hyperbranched polyetliyleneimine 4 having a branching degree of 90% was synthesized by repeating the reactions represented in Reaction schemes 1 and 2 above three times. Hereinafter, tlie details will be described. [0110] (Synthesis of Modified Polyethyleneimine 4A: Reaction scheme 1) Modified polyetliyleneimine 4A was synthesized according to Reaction scheme 1 above. Tlie detailed operation is as follows. In 53 mL of isopropanol, 8.0 g of polyetliyleneimine (50% aqueous solution) manufactured by MP Biomedicals, LLC. was dissolved, 13.3 g (93 mmol) of N-Boc aziridine is added thereto, and the resultant was refluxed for 8 hours while heating, thereby obtaining modified polyetliyleneimine 4A having a structure in which a Boc-aniinoethyl group was introduced into polyetliyle~ieimine. It was confirmed that N-Boc aziridine of the raw material was not present by thin-layer chroniatography (TLC). A small aliiount of the resultant thus obtained was taken as a sample and then 'H-NMR measurement of the sample was performed, thereby confirming the structure thereof. Tlie introduction rate of the Boc-aminoetliyl group with respect to polyetliyleneimine was calculated to be 95% from 'H-NMR data. 'H-NMR (CD30D): 6 3.3 - 3.0 (br. S, 2), 2.8 - 2.5 (BE S, 6.2), 1.45 (s, 9) [Olll] (Synthesis of Branched Polyethyleneirnine 4A: Reaction scheme 2) 32 Branched polyethyleneimine 4A was synthesized according to Reaction scheme 2 above using the modified polyethyleneimine 4A as the starting material. The detailed operation is as follows. To an isopropanol solutioll of the lliodified polyethyle~leimine4 A, 18 mL of 12N hydrochloric acid was gradually added. The solution thus obtained was stirred at 50°C for 3 hours while heating, and attention was paid to the generation of gas. Reaction product in the form of gum was generated in the reaction solution together with the generation of gas. The reaction solution was cooled after generation of gas was completed. After cooling, the solvellt separated from this reaction product in the form of gum was removed, and then the remaining reaction product was washed with 15 mL of methanol four times. The remaining reaction product was dissolved in water, and the chlorine ion was removed by an anion exchange poly~~letrh,e reby obtaining 26 g (purity: about 30%) of branched polyethyleneimine 4A. 'H-NMR (D20): 6 2.8 - 2.4 (be ni) [0112] (Synthesis of Modified Polyetllylelleimine 4B: Reaction scheme 1) Modified polyethyleneimine 4B was synthesized according to Reaction scheme 1 above usi~~thge branched polyetllyleneimine 4A as the starting material. The detailed operation is as follows. In 3 1 mL of isopropanol, the branched polyethyleneimiiie 4A (9.1 g, purity: about 30%) was dissolved, 7.8 g (54.4 tnniol) of N-Boc aziridine is added thereto, and the resulta~lwt as refluxed for 8 llours while heating, thereby obtaining modified polyethyleneimine 4B having a structnre in which a Boc-aminoethyl group was introduced into polyethyieneimine. It was confirmed that N-Boc aziridine of the raw material was not present by thin-layer chromatography (TLC). A small amount of the resultant thus obtained was taken as a sample and then 'H-NMR measurement of the sample was performed, thereby confirnling the structure thereof. The introduction rate of the Boc-aminoetliyl group with respect to polyethylelieilnille was calculated to be 90% from 'H-NMR data. 'H-NMR (CD30D): 6 3.3 - 3.0 (br. s, 2), 2.8 - 2.5 (Br. S, 6.2), 1.45 (s, 9) [0113] (Sylltl~esiso f Branched Polyetllyleneimine 48: Reaction scheme 2) Branched polyethylenei~iline4 B was synthesized according to Reaction scheme 2 above using the modified polyethyleneimine 4B as tlie starting material. The detailed operation is as follows. To an isopropanol solutioll of the ~ilodifiedp olyetliyleneimine 4B, 13 IIIL of 12N hydrochloric acid was gradually added. The solution thus obtained was stirred at 50°C for 33 4 hours while heating, and attention was paid to the generation of gas. Reaction product in the for111 of gum was generated in the reaction solution together with the generation of gas. The reaction solution was cooled after generation of gas was completed. After cooling, the solvent separated from this reaction product in the form of gum was removed, and then the renlaining reaction product was washed with 10 mL of methanol thee times. The remaining reaction product was dissolved in water, and the chlorine ion was removed by an anion exchange polynlel; thereby obtaining 11.29 g (purity: about 40%) of branched polyethyleneimine 4B. I H-NMR (D20): 6 2.8 - 2.4 (br. m) [0114] (Synthesis of M odified Polyethyle~leimine4 C: Reaction scheme 1 ) Modified polyethylenein~ine 4C was synthesized according to Reaction scl~enle 1 above using the branched polyethylenein~ine4 B as the starting material. The detailed operation is as follows. I11 22.5 mL of isopropanol, the branched polyethyleneilnine 4B (4.7 g, purity: about 40%) was dissolved, 5.6 g (39.4 nlnlol) of N-Boc aziridine is added thereto, and the resultant was refluxed for 8 hours while heating, thereby obtaining modified polyetllj~leneimine4 C having a structure in which a Boc-aminoethyl group was introduced into polyethyleneimine. It was confirmed that N-Boc aziridine of the raw material was not present by thin-layer chromatograpll~(~T LC). A small amount oft he resultant thus obtained was taken as a sample and then 'H-NMR nleasurement of the sample was perfornled, thereby confirming the structure tthereof. The introduction rate of the Boc-aminoethyl group with respect to polyethyleneilnine was calculated to be 90% from 'H-NMR data. 'H-NMR (CD30D):6 3.3 - 3.0 (br. s, 2), 2.8 - 2.5 (Br. s, 6.2), 1.45 (s, 9) [0115] (Synthesis of Hyperbranched Polyethyleneimine 4: Reaction scheme 2) 13yperbranched polyethyleneinline 4 was synthesized according to Reaction scheme 2 above using the nlodified polyetl~yleneimine 4C as the starting material. The detailed operation is as follows. To an isopropanol solution of the modified polyethyleneimine 4C, 9 mL of 12N I~ydrochlorica cid was gradually added. The solution thus obtained was stirred at 50°C for 4 hours while heating, and attention was paid to the generation of gas. Reaction product in the form of gum was generated it1 the reaction solution together with the generation of gas. The reaction solution was cooled after generation of gas was completed. After cooling, the solvent separated from this reaction product in the form of gun1 was removed, and then the remaining reaction product was washed with 10 mL of methanol three times. The 34 remaining reaction product was dissolved in water, and the chlorine ion was removed by an anion exchange polymer, thereby obtaining 8.4 g (purity: about 40%) of ultrahyperbranched polyethyleneimine 4. 'H-NMR (D20): 6 2.8 - 2.4 (br. m) [0116] With regard to the hyperbranched polyethyleneinline 4, cationic functional group equivalent, the amount (% by mole) of primary nitrogen atom, tlie amount (% by mole) of secondary nitrogen atom, the amount (% by mole) of tertiary nitrogen atom, the amount (% by mole) of quaternary nitrogen atom, and the branching degree were measured, respectively, in the same manlier as in tlie hyperbranched polyethyleneimine 1. As a result, the cationic fi~nctionalg roup equivalent was 43, the amount ofp rimary nitrogen atom was 47% by mole, the amount of secondary nitrogen atom was 5% by mole, the amount of tertiary nitrogen atom was 48% by mole, tlie amount of quaternary nitrogen atom was 0% by mole, and tlie branching degree was 90%. The weight average molecular weight of the hyperbranched polyethyleneitnine 4 was not able to be measured at the moment, but it is thought that the weight average molecular weight thereof is in the range of from 2,000 to 1,000,000 in consideration of the synthesis conditions described above. [O 11 71 [Example 11 The sealing composition 1 (2.0 mL) was dropped on the interlayer dielectric layer (hereinafter, it is referred to as a "low-k film" in some cases) at a constant speed for 30 seconds while rotating the silicon wafer having the low-k film formed thereon using a spin coater at 600 rpm, and then drying was performed by rotating at 2,000 rpm for 10 seconds. Thereaftel; the silicon wafer was transferred onto a hot plate, and then subjected to a heat treatment in the air at 125'C for 1 minute. Subsequently, the silicon wafer was reinstalled to the spin coater, and then 3.0 mL of ultrapure water was dropped on the surface of the side, on which the sealing colnposition 1 had been dropped, of tlie silicon wafer at a constant speed for 30 seconds while rotating at 600 rp~na, nd then drying was performed by rotating at 2,000 rpm for 60 seconds. This film forming operation of the sealing layer was repeated three times. By the method described above, a layer (sealing layer) of the polymer contained in the sealing composition 1 was formed on the interlayer dielectric layer, thereby obtaining a laminated body (liereinafter, it is also referred to as a "sample (Siilow-k1PEI)") having a structure in which a silicon wafer, an interlayer dielectric layel; and a sealing layer were laminated in order. Meanwhile, as water, ultrapure water (Milli-Q water ~nanufacturedb y Millipore Corporation, resistance: 18 MQ.cm or less (25OC)) was used. [0127] Evaluation of sealing property was performed using the sample (SVlow-WPEI). The evaluatiott of sealing property was performed by measuring tlie toluene adsorption characteristics on the sealing layer (TEI) surface of the sample (Siiiow-kPEI). In this measurement of the toluene adsorption characteristics, the sealing property that prevents the wiring material (copper or the like) from invading into the low-k film is great as the amount of toluene adsorbed is small. Tlie adsorption of toluene was measured using an optical porosimeter (PS-1200) tnanufactured by SEMILAB JAPAN K. K. As the measuring method, a technique described in M. R. Baklanov, K. P. Mogilnikov, V. G. Polovinkin, and I?. N. Dultsey, Journal of Vacuum Science and Technology B (2000) 18, pp. 1385 to 1391 was adopted. Specifically, the sample chamber having the sample (Siilow-kfPEI) therein was evacuated to 5 mTorr in a temperature range of fro111 23°C to 26OC, and the toluene gas was sufficiently gradually introduced into the saniple chamber. At each of the pressures, the refractive index of the low-k film was measured in situ by an ellipsolneter instrument. 3 8 This operation was performed until the pressure in the sample chamber reached to the saturated vapor pressure of toluene. I11 the same manner, the refractive index at each of the pressures was measured along with evacuating little by little the atmospliere in the sample chamber. By this operation, change in refractive index caused by the adsorption and desorption of toluene 011 the low-k film was obtained. Moreover, the isotliermal line of the toluene gas adsorption and desorption was calculated from the relative pressure characteristic of tlie refractive index using the Lorentz-Lorenz equation. The isothermal line of the toluene gas adsorption and desorption is illustrated in Fig. I . The liorizontal axis in Fig. 1 represents the relative pressure of toluene (PRO: here, P represents tlie partial pressure of toluene at room temperature and Po represents the saturated vapor pressure of toluene at room temperature.), and the vertical axis represents the volume fraction (the ratio of the volume of toluene adsorbed at mom temperature with respect to the volun~eo f the entire low-k fillii) oft he atnount oft oluene adsorbed. The volume fraction of the amount of toluene adsorbed was obtained based on the refractive index of the low-k film using the Lorentz-Lorenz equation. The sealing property is excellent as the relative pressure of toluene is large in a case in which the volume fraction of the amount of toluene adsorbed is the same. [0128] The following measurement was performed in order to investigate the thickness (film thickness) of the sealing layer (PEI) in the sample (Sillow-k/PEI). In other words, the same operation as in was performed except that tile silicon wafer having an interlayer dieiectric layer fornied thereon was changed to a silicon wafer not having an interlayer dielectric layer formed thereon in . In this manner, a sample (hereinaftel; it is also sililply referred to as a "sanlple for measure~nent") for measurement of the thickness of the sealing layer, which had a structure having a sealing layer fornled directly on the silicon wafer, was obtained. The thickness (unit: nm) of tlie sealing layer in the sample for measurement thus obtained was measured by a co~iventionaml ethod using an ellipsometer of an optical porosimeter (PS-1200) manufactured by SEMILAB JAPAN K. K. The results of the measureliients of the sealing layer thickness (film thickness) are listed in Table 1. [0129] [Exanlple 21 A sealing composition for a semiconductor (hereinafter, it is referred to as the 39 "sealing composition 2") was prepared in the same manner as in Example 1 except that the hyperbranched polyethyleneimine 1 was changed to the hyperbranched polyethyleneimine 2 of the same mass. The same measurements and evaluations as in Example 1 were performed. The result of evaluation on the sealing property (isothermal line of toluene gas adsorption and desorption) is illustrated in Fig. 1. In addition, the results of the respective measurements with regard to the sealing composition 2 are listed in Table 1. [0130] [Example 31 The application (preparation of sample (Sillow-WPEI)) of sealing composition for a semiconductor was performed in the same manner as in Example 1 except that the pore radius of the low-k film was changed from 2.6 nm to 2.1 nm by changing the weight of polyoxyethylene (20) stearyl ether to 31.3 g, and the number of the film forming operation of the sealing layer was changed fro111 tlxee times to one time. The same measurements and evaluations as in Example 1 were performed. The result of evaluation on the sealing property (isothermal line of toluene gas adsorption and desorption) is illustrated in Fig. 2. [013 11 [Example 41 A sealing con~positionfo r a semiconductor (hereinaftel; it is referred to as the "sealing composition 3") was prepared in the same manner as in Example 3 except that the hyperbranched polyethyleneimine 1 was changed to the hyperbranched polyethyleneimine 3 of the same mass. The same measurements and evaluations as in Example 3 were performed. The result of evaluation on the sealing property (isothermal line of toluene gas adsorption and desorption) is illustrated in Fig. 2. In addition, the results of the respective measurements with regard to the sealing composition 3 are listed in Table I. [0132] [Comparative Example I] A sealing composition for a seiniconductor (hereinafter, it is referred to as the "comparative sealing composition 1") was prepared in the same manner as in Example 1 except that the hyperbranched polyethylenein~ine 1 was changed to the polyethyleneimine 1 (prepared by purifying polyethyleneimine manufactured by MP Biomedicals, LLC. using a hollow fiber filter of 10k and removing the low n~olecularw eight components therefrom) of the same mass. The same measurements and evaluations as in Example 1 were performed. The result of evaluation on the sealing property (isothermal line of toluene gas 40 adsorption and desorption) is illustrated in Fig. 1. In addition, the results of the respective measurements with regard to the comparative sealing compositioll 1 are listed in Table 1. [0133] [Comparative Example 21 A sealing composition for a semiconductor (hereinafter, it is referred to as the "comparative sealing composition 2") was prepared in the same manner as in Example 1 except that the hyperbranched polyethyleneimine 1 was changed to the polyethyleneimine 2 (polyethyleneimine Lupasol WF manufactured by BASF Japan Ltd.) of the same mass. The same measurements and evaluations as in Example 1 were performed. The result of evaluation on the sealing property (isothermal line of toluene gas adsorption aud desorption) is illustrated in Fig. 1. In addition, the results of the respective measurements with regard to the comparative sealing composition 2 are listed in Table 1. [0134] [Comparative Example 31 A sealing composition for a semiconductor (hereinafter, it is referred to as the "comparative sealing composition 3") was prepared in the same manner as in Example 1 except that the hyperbranched polyethyleneimine 1 was changed to the polyethyleneimine 3 (polyethyleneimine nlanufactured by MP Biomedicals, LLC.) of the same mass. The same measurements and evaluations as in Example 1 were perfornled. The result of evaluation on the sealing property (isothermal line of toluene gas adsorption and desorption) is illustrated it1 Fig. 1. In addition, the results of the respective measurements with regard to the comparative sealing conlposition 3 are listed in Table 1. [O 1351 [Comparative Example 41 The same measurements and evaluations as in Exalnple 1 were performed except that the hyperbranched polyethyleneimine 1 was not used (that is, the sealing compositioll 1 was changed to water of the same mass). The result of evaluation on the sealing property (isothermal line of toluene gas adsorption and desorption) is illustrated in Fig. 1. [O 1361 [Conlparative Example 51 A sealing conlposition for a semiconductor (hereinafter, it is referred to as the "comparative sealing composition 3") was prepared in the same manner as in Example 3 except that the l~yperbranchedp olyethyleneimine 1 was changed to the polyethyleneimine 3 (polyethyleneimine manufactured by MP Biomedicals, LLC.) of the same mass. The same measurements and evaluations as in Example 3 were performed. 4 1 The result of evaluation on the sealing property (isothermal line of toluene gas adsorption and desorption) is illustrated in Fig. 2. I . . " . . - 80'1 uognq!.wrp 55'91 SL'Z E8'P LP'L I IUZI~M~ eln3ayow PLLOEI 89511 882E81 St.b6SI SLSOP . I E ~ ~ ~ ~ IaOSvU.rIa i\v $yZ!afi E Z z z au!u!aualLq$aL1od 1 I au!m!aualKq$aLlo Table 1 (continued) Comparative Example 5 Comparative sealing composition z Kind Example 4 Sealing Kind composition 3 Hyperbranched polyethyleneimine 1 Comparative Example 4 (Water) Example 3 Sealing composition 1 poHlyyeptehryblreannecimheidn e 7 - Polyethyleneimine 3 [0138] Fig. 1 is the isothermal lines (a graph illustrating the relation between the relative pressure of toluene and tlie volume fraction of the amount of toluene adsorbed) of toluene gas adsorption and desorption in Examples 1 and 2 and Coniparative Examples 1 to 4, in which the pore radius of tlie low-k film was 2.6 nm and tlie number of the film forming operation of sealing layer was 3 times. The sealing property is excellent as the relative pressure of toluene is large in a case in which tlie volume fraction of the amount of toluene adsorbed is the same (for example, see the dashed line in Fig. 1). [0139] As illustrated in Fig. 1, tlie sealing property with respect to the low-k film was excellent in Exa~nples 1 and 2, in whicli the branching degree of the polymer was 48% or more. Particularly in Example 1, the volume fraction of the amount of toluene adsorbed was significatitly small over tlie whole range (0 to 1) of the relative pressure of toluene, and significantly excellent sealing property was exhibited. [0140] In addition, in Examples I and 2 and Comparative Examples 1 to 3, the thickness of the sealing layer, which was measured according to < Measureliient of Thickness of Sealing Layer> described above, was as listed in Table 1. Meanwhile, in Table I, the term 'W. D." (no data) indicates that there is no result of measurement since the measurement is not performed. Frotn the result of evaluation on sealing property illustrated in Fig. 1 and the measurement result of the thickness of sealing layer listed in Table 1, it is confirmed that the sealing layers in Examples 1 and 2 exhibit excellent sealing property with respect to the low-k film in spite of the fact that tlie tliicktiess thereof is significantly thin to be about 12 nm. [0141] Fig. 2 is the isothermal lines (a graph illustrating the relation between the relative pressure of toluene and the volume fraction of the amount of toluene adsorbed) of toluene gas adsolition and desorption in Exatiiples 3 and 4 and Comparative Example 5, in which the pore radius of the low-k film was 2.1 an1 and the number of the film forming operation of sealing layer was 1 time. As illustrated in Fig. 2, tlie sealing property with respect to the low-k film was excellent in Examples 3 and 4, in xvliich the branching degree of tlie polymer was 48% or more. [0142] In addition, in Examples 3 and 4 and Coniparative Example 5, the thickness of the sealing layel; which was measured according to described above, was as listed in Table 1. From tlie result of evaluation on sealing property illustrated in Fig. 2 and the 45 measurement result of tlie thickness of sealing layer listed in Table 1, it is confirmed that the sealing layers in Examples 3 and 4 exhibit excellent sealing property with respect to the low-k film in spite of the fact that the thickness thereof is significantly thin to be about from 4to5nm. [O 1431 [Example 51 Evaluation on the sealing property of the sealing layer formed through a heat treatment (heat treatment B described below) at 350°C was performed according to the following procedure. A silicon wafer with low-k film @ore radius: 1.6 nm) was prepared by changing the pore radius of the low-k fihn from 2.1 nm to 1.6 nm by changing the weight of polyoxyethylene (20) stearyl ether to 20.9 gin Example 3. The silicon wafer with low-k fill11 (pore radius: 1.6 nm) tlius prepared was installed to a spin coater, and the sealing composition 1 (1.0 mnL) was dropped on the low-k film and then held for 23 seconds. Subsequently, the silicon wafer was rotated at 4,000 rpm for 1 second, further rotated at 600 rpm for 30 seconds, and then ful-tlier rotated at 2,000 rpm for 10 seconds, thereby performing drying. Thereafter, the silicon wafer was transferred onto a hot plate, and then subjected to a heat treatment (hereinafter, it is also referred to as the "heat treatment A") in the air at 125OC for 1 minute. Subsequently, the silicon wafer was reinstalled to the spin coatel; and then 3.0 mL of ultrapure water was dropped on the surface of the side, on which tlie sealing composition 1 had been dropped, of the silicon wafer at a constant speed for 30 seconds while rotating at 600 rpm, and then drying was performed by rotating at 2,000 rprn for 60 seconds. Subsequently, a heat treatment (hereinafter, it is also referred to as the "heat treatment B") was performed under an atmosphere of nitrogen at 350°C for 2 mintbes, thereby obtaining a sample (Sillow-WPEI) of Example 5. The same measurements and evaluations as in Example 3 were performed (see Table 2 below) using tlie sample (Sillow-k/PEI) of Example 5 tlius obtained. Tlie result of evaluation 011 the sealing property (isothermal line of toluene gas adsorption and desorption) is illustrated in Fig. 3. [0144] [Comparative Example 61 Tlie same tneasuretnents and evaluations as in Exaniple 5 were performed except that tlie hyperbranclied polyethyleneimine 1 was changed to the polyethyleneimine 3 (polyethyleneimine manufactured by MP Biomedicals, LLC.) of the same mass (see Table 2 below). The result of evaluation on the sealing property (isothermal line of toluene gas adsorption and desorption) is illustrated in Fig. 3. 46 [0146] Fig. 3 is the isothernlal lines (a graph illustrating the relation between the relative pressure of toluene and the volume fraction of the amount of toluene adsorbed) of toluene gas adsorption and desorption in Example 5 and Comparative Example 6. As illustrated in Fig. 3, the sealing property with respect to the low-k film is superior in Example 5 compared to Comparative Example 6. This is presumed to be because the thermal decomposition of the polymer caused by the heat treatment B at 350°C is suppressed in Example 5 since the branching degree of the polytner contained in the sealing layer is higher (that is, the polymer is bulky) in Example 5 conlpared to Comparative Example 6. In addition, from the result of evaluation on sealing property illustrated in Fig. 3 and the measure~nenrt esult of the thickness of sealing layer listed in Table 2, it is confirmed that the sealing layer in Example 5 exhibits excellent sealing property with respect to the low-k film in spite of the fact that the thickness thereof is significantly thin to be 6.0 m. [O 1471 [Exatnple 61 A sealing composition for a semiconductor (hereinafter, it is referred to as the "sealing con~position4 ") was prepared in the same manner as in Comparative Example 5 except that the polyethylenei~nine3 (polyethyleneimine manufactnred by MP Biomedicals, LLC.) in Comparative Example 5 was changed to the hyperbranched polyethylenei~nine4 (polyethyleneimine having a branching degree of 90%) of the same mass. The same meas~urernentsa s in Comparative Example 5 were performed. In this sealing composition 4, the content of Na was less than I ppb by weight, the content of K was less than 1 ppb by weight, and the volume average particle diameter was less than 10 nm. Next, a silicon wafer wit11 low-k filnl (pore radius: 2.1 n~nw) as prepared in the same manner as in Comparative Example 5. The silicon wafer with low-k film (pore radius: 2.1 nm) tllus prepared was installed to a spin coatel; and the sealing composition 4 (1.0 ~ I Lw) as dropped on the low-k film and then held for 23 seconds. Subsequently, the silicon wafer was rotated at 4,000 rpm for 1 second, further rotated at 600 rpm for 30 seconds, and then ful-tller rotated at 2,000 rpm for 10 seconds, thereby perfornling drying. Thereafter, the silicon wafer was transferred onto a hot plate, and then subjected to a heat treat~nentin the air at 125OC for 1 minute. Subsequently, the silicon wafer was reinstalled to the spin coatel; and then 3.0 IIIL of ultrapure water was dropped on the surface of the side, on which the sealing cotnposition 4 had been dropped, of the silicon wafer at a constant speed for 30 seconds while rotating at 600 rpln, and then drying was performed by rotating at 2,000 rpm for 60 seconds. A sample (Sillow-WPEI) of Exatnple 6 was obtained in the manner as described above. 48 The same measurements and evaluations as in Comparative Example 5 were performed (Fig. 4) using the sample (Sillow-k/PEI) of Example 6 thus obtained. In addition, the thickness of the sealing layer was measured ia the same maunes as in Comparative Example 5. As a result, the thickness of the sealing layer was 4.0 nm. [0148] The result of evaluation 011 the sealing property (isothermal line of toluene gas adsorption and desorption) in Example 6 is illustrated in Fig. 4. As illustrated in Fig. 4, the sealing property with respect to the low-k film in Example 6, in which the branching degree of the polymer was 90%, was also excellent in the same manner as it1 other Examples. As described above, it is confirmed that the sealing layer it1 Example 6 exhibits excellent sealing property with respect to the low-k film in spite of the fact that the thickness thereof is significantly thin to be 4.0 nm. [0149] The disclosure of Japanese Patent Application No. 2012-007151 is illcorporated herein by reference in its entirety. All publications, patent applications, and techtiical standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or technical standard was specifically and individually indicated to be incorporated by reference. I AMENDED CLAIMS 1. A sealing cotnposition for a semiconductor, comprising a polytner that includes two or tnore cationic fitnctional groups including at least one of a tettiaty nitrogen atotn or a quaternary nitrogen atom, that has a weight average tnolecular weight of from 2,000 to 1,000,000, and that has a branching degree of 48% or tnore, wherein a content of sodium and a content of potassium it1 the sealing co~npositiona re each I0 ppb by weight or less on an element basis. 2. The sealing co~npositionf or a set~~icondactaocrc ording to claim I, wherein the polymer includes a structural unit that is derived from an alkyle~lei~ninheav ing frotn 2 to 8 carbon atotns and that includes a tettiaty nitrogen atom as a catiotlic fut~ctionagl roup. 3. The sealit~gc onlposition for a sen~iconductoar ccording to claitn 2, wherein the polynler further itlcludes a structitral unit that is derived from an alkyle~lei~llinheav ing frotn 2 to 8 carbon atotns and that includes a secondary nitrogen atom as a cationic fitnctional group. The e c o t n p o s i t i o n for sdlitlga setniconductor according to any one of claim 1 to claim 3, wherein the polymer iacludes primary nitrogen atoms, and a proportion of the primaty nitrogen atotns to all the nitrogen atotns in the polymer is 33% by mole or more. 5. The sealing cotl~positionfo r a semiconductor according to any one of claitn 1 to I elaim4c-, wherein the branching degree of the polymer is 55% or tnore. 6. The sealing composition for a setnicondoctor according to any one of claim 1 to I d a i l & M , wherein the sealing co~npositionh as an average particle diameter tneasured by a dynamic light scattering tnethod of 150 nm or less. 7. The sealing cotnposition for a se~niconductora ccording to any one of claitn I to I c&i+3-, wherein the polymer is a polyethyleneimine or a derivative of a polyethyleneimine. 8. The sealing co~l~positiofonr a semiconductor according to any one of claim 1 to 1 elai