Specification
CURABLE ENCAPSULANT COMPOSITION, DEVICE INCLUDING SAME,
AND^ASSOCIATED METHOD
CROSS REFERENCE TO RELATED APPLICATIONS
This patent application is a continuation-in-part patent application of U.S. patent application Serial No. 11/022,904 filed December 22, 2004, the entire contents of which is hereby incorporated by reference.
BACKGROUND TECHNICAL FIELD
The invention may include embodiments that relate to an encapsulant for encapsulating electronic components. The invention may include embodiments that relate to a method of making and/or using the encapsulant. The invention may include embodiments that relate to an electronic device that includes the encapsulant.
DISCUSSION OF RELATED ART
Electronic components, such as integrated circuits, may be encapsulated by transfer molding for environmental protection and to maintain structural and functional integrity. The encapsulating material may be a polymeric composition. Such encapsulating materials may be useful for encapsulation of semiconductors, semiconductor integrated circuits, passives, passive networks, multichip modules, opto-electronic devices and numerous other applications.
During molding, currently available encapsulating materials may stick to process equipment, or may be otherwise problematic. At room temperature, the encapsulating materials may be liquid or semi-solid putties.
U.S. Patent. Nos. 4,632,798; 4,632,798; 5,355,016; 5,998,876; and 5,272,377 address one or more encapsulant issues and disclose materials related thereto. International Publication No. WO 03/072628 Al discloses a novolac type phenolic epoxy resin composition for encapsulating electronic parts.
It may be desirable to have an encapsulating material with different properties than encapsulants that are currently available. It may be desirable to have a cured encapsulant produced with materials and/or methods different from those materials and/or methods currently available. It may be desirable to have an electronic device that includes an encapsulant produced with materials and/or methods different from those materials and/or methods currently available.
BRIEF DESCRIPTION
In one embodiment, a curable encapsulant composition may be provided. The composition may include a mixture of a functionalized polymer and at least one reactive monomer composition. At least one reactive monomer or reactive monomer component of the reactive monomer composition may be a room temperature solid and may be present in the reactive monomer composition an amount in a range of greater than about 20 weight percent based on the total weight of the reactive monomer composition. The encapsulant, at low temperature, may be solid or tack-free, or both solid and tack-free.
In one embodiment, an electronic device may be provided. The electronic device may include an encapsulated circuit or die. The encapsulating composition may include a mixture of a functionalized polymer and a reactive monomer composition. At least one reactive monomer in the reactive monomer composition may be a room temperature solid and may be present in an amount in a range of greater than about 20 weight percent based on the total weight of reactive monomer composition. The mixture may be solid and/or tack-free at low temperature.
In one embodiment, a method of making an encapsulant may be provided. The method may include mixing a functionalized polymer with a reactive monomer composition. The reactive monomer composition may include a reactive monomer that is a low temperature solid and that is present in the reactive monomer composition an amount in a range of greater than about 20 weight percent based on the total weight of reactive monomer composition. The functionalized polymer and the reactive monomer composition may be heated to a temperature sufficient to soften
or liquefy, and the functionalized polymer and the reactive monomer composition may be mixed with each other. The softened or liquid mixture may be cooled to form an encapsulant composition that is solid and/or tack-free at low temperature.
In another embodiment, a method of encapsulating at least a portion of the electronic or optical device may be provided. The method may include melting at least a portion of pellets or powder, in which the portion may include a mixture of a functionalized polymer and the reactive monomer composition. The reactive monomer composition may include a reactive monomer that may be a low temperature solid, and which is present in the reactive monomer composition in an amount in a range of greater than about 20 weight percent based on the total weight of reactive monomer composition. The pellets or powder, at room temperature, may be solid and/or tack-free. The molten portion may be flowed into contact with the portion of the electronic or optical device.
BRIEF DESCRIPTION OF DRAWINGS
Fig. 1 is a perspective, cut-away view of an electronic assembly in accordance with an embodiment of the invention.
Fig. 2 is a cross-sectional view of the electronic assembly, taken through section 2-2 of Fig. 1.
DETAILED DESCRIPTION
The invention may include embodiments that relate to an encapsulant for encapsulating electronic components. The invention may include embodiments that relate to a method of making and/or using the encapsulant. The invention may include embodiments that relate to an electronic device that includes the encapsulant.
Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as "about", is not to be limited to the precise value specified, and may include values that differ insubstantially from the
specified value. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Tack free may refer to a surface that does not possess pressure sensitive adhesive properties at about' room temperature. By one measure, a tack free surface will not adhere or stick to a finger placed lightly in contact therewith at about 25 degrees Celsius, the temperature may be different using other specified measures.
Abbreviations may have the meanings indicated in Table 1.
Table 1. Abbreviations.
(Table 1 Removed)
In a first aspect, a curable encapsulant composition is disclosed. The composition may include a mixture of a functionalized polymer and a reactive monomer composition. The reactive monomer composition may include a reactive monomer that may be a room temperature solid and that may be present in the reactive monomer composition an amount in a range of greater than about 20 weight percent based on the total weight of reactive monomer composition. The mixture, at about low temperature, may be solid or tack-free, or both solid and tack-free.
Suitable functionalized polymers may include one or more novolac resin, polycarbonate, polyester, olefin polymer, or poly(arylene ether).
In one aspect, a suitable functionalized polymer may be produced by capping the hydroxyl radicals of novolac resins with (meth)acrylates. A portion of the hydroxyl groups may be capped with (meth)acrylates, while the remaining hydroxyl groups may be capped with alky] groups or other radicals that do not participate in polymerization.
Suitable novolacs niay be made by condensation of phenols (such as phenol, cresol, resorcin, catechol, bisphenol A, bisphenol F, phenylphenol, or dihydroxynaphthalene) with an aldehyde (such as formaldehdye, benzaldehyde, or salicylaldehyde) in the presence of an acid catalyst. Novolacs that may be made by condensation of phenols and formalin (aqueous formaldehyde) may be sold under the trademark SHONOL® by Showa Hipolymer Co., Ltd. (Tokyo, Japan). Suitable novolacs may be those that may have two or more phenolic hydroxyl groups, and may include, but may be not limited to, phenolic novolac, cresol novolac (such as methacrylated O-cresol novolac), t-butyl phenolic novolac, nonyl phenolic novolac, aralkyl type of phenol novolac (such as phenol aralkyl novolac or napthol aralkyl novolac synthesized from phenols and/or napthols and for instance, dimethoxyparaxylene or bis (methoxymethol) biphenyl}, dicyclopentadiene phenolic novolac, or combinations of two or more thereof.
Suitable functionalized polycarbonate may include bisphenol A polycarbonate having at least one methacryloyloxy group. In one embodiment, the functionalized
polycarbonate may include hydroxyl-terminated bisphenol A polycarbonate which has been further reacted with methacryloyl chloride.
Suitable functional!zed polyesters may include poly(ethylene teraphthalate) (PET) having a terminal acryloyloxy group. In one embodiment, functionalized polyesters may be prepared from corresponding hydroxyl-terminated polyesters.
Suitable functionalized olefin polymers may include polystyrene having at least one methacryloyloxy group. In one embodiment, functionalized olefin polymers may be prepared from the corresponding hydroxyl-terminated olefin polymers.
Suitable functionalized poly(arylene ether) may include one or more of a capped poly(arylene ether), a ring-functionalized poly(arylene ether), or an acid- or anhydride-functionalized poly(arylene ether), or a combination of these poly(arylene ether)s.
A capped poly(arylene ether) may have more than about 50 percent of the free hydroxyl groups functional zed by reaction with a capping agent, relative to the number of corresponding uncapped poly(arylene ether). In on embodiment, the percentage of capped hydroxyls may be in a range of from about 50 percent to about 75 percent, from about 75 percent to about 90 percent, from about 90 percent to about 95 percent, or from about 95 percent to about 99 percent.
A suitable capped poly(arylene ether) may include methacrylate-capped poly(2,6-dimethyl phenylene ether) (abbreviated herein as MACPDMPE), or may be represented by the structure
.
wherein Q may be the residuum of a monohydric, dihydric, or polyhydric phenol, preferably the residuum of a monohydric phenol or a dihydric phenol; y may be from 1 to about 100; J may include repeating structural units having the formula
(Formula Removed)
wherein m may be 1 to about 200, and R1 and R3 may be each independently hydrogen, halogen, primary or .secondary Ci-Qj alkyl, C^-C\2 alkenyl, Ci-C^ alkynyl, Ci-C|2 aminoalkyl, Ci-0i2 hydroxyalkyl, phenyl, CpC|2 haloalkyl, Ct-C]2 hydrocarbyloxy, C2-C|2 halohydrocarbyloxy wherein at least two carbon atoms may be disposed between the halogen and oxygen atoms, or the like; R2 and R4 may be each independently halogen, primary or secondary Ci-C]2 alkyl, C2-Ci2 alkenyl, €2-C]2 alkynyl, Ci-Ci2 aminoalkyl, C\-C\2 hydroxyalkyl, phenyl, C|-C]2 haloalkyl, Cj-C|2 hydrocarbyloxy, C2-C)2 halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms, or the like; and K may be a capping group produced by reaction of a phenolic hydroxyl group on the poly(arylene ether) with a capping agent. The resulting capping group, K, may be
or the like, wherein R5 may be C|-C|2 hydrocarbyl optionally substituted with one or two carboxylic acid groups, or the like; R6-R8 may be each independently hydrogen, C|-C|g hydrocarbyl optionally substituted with one or two carboxylic acid groups, €2-C|g hydrocarbyloxycarbonyl, nitrile, formyl, carboxylic acid, imidate, thiocarboxylic acid, or the like; R9-R13 may be each independently hydrogen, halogen, C|-C)2 alkyl, hydroxy, amino, carboxylic acid, or the like; and wherein Y may be a divalent group such as
(Figure Removed)
or the like, wherein R14 and R15 may be each independently hydrogen, Ci-Ci2 alkyl, or the like.
Hydrocarbyl refers to a residue that contains only carbon and hydrogen, except where otherwise indicated. The residue may be aliphatic or aromatic, straight-chain, cyclic, bicyclic, branched, saturated, or unsaturated. The hydrocarbyl residue may contain heteroatoms over and above the carbon and hydrogen members of the substituent residue. The hydrocarbyl residue may contain carbonyl groups, amino groups, hydroxyl groups, carboxylic acid groups, halogen atoms, or the like, or it may contain heteroatoms within the backbone of the hydrocarbyl residue.
In one embodiment, Q may be the residuum of a phenol, including polyfunctional phenols, and may include radicals of the structure
(Figure Removed)
wherein R16 through R19 may be each independently hydrogen, halogen, primary or secondary C1-C2 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C2-C12 aminoalkyi, C2-C12 hydroxyalkyl, phenyl, C1-C12 haloalkyl, C1-C12 hydrocarbyloxy, C2-C12 halohydrocarbyloxy wherein at.least two carbon atoms separate the halogen and oxygen atoms, or the like; R2 and R4 may be each independently halogen, primary or secondary C1-C12 alkyl, C2-C)2 alkenyl, C2-C12 alkynyl, C1-C12 aminoalkyi, C1-C12hydroxyalkyl, phenyl, C]-Ci2 haloalkyl. C|-C|2 hydrocarbyloxy, C halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms, or the like; X may be hydrogen, Ci-C]g hydrocarbyl, or Cj-Cjg hydrocarbyl containing a substifuent such as carboxylic acid, aldehyde, alcohol, amino radicals, or the like; X also may be sulfur, sulfonyl, sulfuryl, oxygen, or other such bridging group having a valence of 2 or greater to result in various bis- or higher polyphenols; n (i.e., the number of phenylene ether units bound to X) may be 1 to about 100, preferably 1 to 3, and more preferably 1 to 2. Q may be the residuum of a monohydric phenol, such as 2,6-dimethylphenol, in which case n may be 1. Q may also be the residuum of a diphenol, such as 2,2>,6,6'-tetramethy]-4,4'-diphenol, in which case n may be 2.
(Figure Removed)
In one embodiment, the uncapped poly(arylene ether) may be defined by reference to the capped poly(arylene ether) Q(J-K), as Q(J-H)y, where Q, 3 and y are defined above. But, a hydrogen atom, H, has taken the place of capping group K. In one embodiment, the uncapped poly(arylene ether) consists essentially of the polymerization product of at least one monohydric phenol having, the structure
(Figure Removed)
wherein R20 through R23 may be each independently hydrogen, halogen, primary or secondary C|-C|2 alkyl, Ca-C|2 alkenyl, C2-C|2 alkynyl, C|-Cj2 aminoalkyi, C]-C|2 hydroxyalkyl, phenyl, C]-Ci2 haloalkyl, C|-Ci2 hydrocarbyloxy, Cz-Ci2 halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms, or the like. In one embodiment, the monohydric phenol may include, for example, 2,6-dimethylphenol, 2,3,6-trimethylphenol, and the like.
The poly(arylene ether) may be a copolymer of at least two monohydric phenols. The uncapped poly(arylene ether) may include poly(2,6-dimethyl-l,4-phenylene ether),
poly(2,6-dimethyl-l,4-phenylene ether-co-2,3,6-trimethyl-l,4-phenylene ether), or a mixture of two or more thereof. The uncapped poly(arylene ether) may be isolated by precipitation and may have a concentration of organic impurities in a range of from about 400 parts per million to about 300 parts per million, or less than about 300 parts per million. Organic impurities may include, for example, 2,3-dihydrobenzofuran, 2,4,6-trimethylanisole, 2,6-dimethylcyclohexanone, 7-methyl-2,3-dihydrobenzofuran, and the like.
In one embodiment, the capped poly(arylene ether) may include at least one capping group having the structure
(Figure Removed)
wherein R24 through R26 may be each independently hydrogen, Ci-C|g hydrocarbyl optionally substituted with one or two carboxylic acid groups, C2-Ci8 hydrocarbyloxycarbonyl, nitrile, formyl, carboxylic acid, imidate, thiocarboxylic acid, or the like. Other suitable capping groups may include acrylate (where R24 through R26 are hydrogen) and methacrylate (where R2" is methyl, and R25 and R26 are hydrogen). Acrylate may refer to one or both of acrylate or methacrylate.
In another embodiment, the capped poly(arylene ether) may include at least one capping group having the structure
(Figure Removed)
wherein R27 may be C|-C 12 hydrocarbyl substituted with one or two carboxylic acid groups, such as C1-C& alkyl.
In yet another embodiment, the capped po)y(arylene ether) may include at least one capping group having the structure
(Figure Removed)
wherein R28 through R32 may be each independently hydrogen, halogen, Ci-C|2 alkyl, hydroxy, amino, carboxylic acid, or the like. Capping groups of this type may include salicylate (where R29 through R32 are hydrogen, and R28 is hydroxy).
In one embodiment, the capped poly(arylene ether) may include at least one capping group having the structure
(Figure Removed)
wherein A may be a saturated or unsaturated C2-Ci2 divalent hydrocarbon group such
as, for example, ethylene; 1,2-propylene; 1,3-propylene; 2-methyl-l,3-propylene;
2,2 -dimethyl-1,3-propylene; 1,2-butylene; 1,3-butylene; 1,4-butylene;
2-methyl-1,4-butylene; 2,2 -dimethyl- 1,4-butylene; 2,3 -dimethyl-1,4-butylene; vinylene (-CH=CH-); 1,2-phenylene; and the like. These capped poly(arylene ether) resins may be prepared, for example, by reacting an uncapped poly(arylene ether) with a cyclic anhydride capping agent. Such cyclic anhydride capping agents may include, for example, maleic anhydride, succinic anhydride, glutaric anhydride, adipic anhydride, phthalic anhydride, and the like.
Other suitable capping agents may include compounds reactive with phenolic groups. Such compounds may include both monomers and polymers containing, for example, anhydride, acid chloride, epoxy, carbonate, ester, isocyanate, cyanate ester, or alkyl halide radicals. Phosphorus and sulfur based capping agents also may be may included. Examples of capping agents may include, for example, acetic anhydride, succinic anhydride, maleic anhydride, salicylic anhydride, polyesters comprising salicylate units, homopolyesters of salicylic acid, acrylic anhydride, methacrylic anhydride, glycidyl acrylate, glycidyl methacrylate, acetyl chloride, benzoyl chloride, diphenyl carbonates such as di(4-nitrophenyl)carbonate, acryloyl esters, methacryloyl esters, acetyl esters, phenylisocyanate, 3-isopropenyl-a,a-dimethylphenylisoeyanate, cyanatobenzene, 2,2-bis(4-cyanatophenyl)propane, 3-(
Documents
Application Documents
| # |
Name |
Date |
| 1 |
4174-DELNP-2007-GPA-(04-08-2008).pdf |
2008-08-04 |
| 2 |
4174-delnp-2007-form-6-(04-08-2008).pdf |
2008-08-04 |
| 3 |
4174-DELNP-2007-Form-2-(04-08-2008).pdf |
2008-08-04 |
| 4 |
4174-DELNP-2007-Form-1-(04-08-2008).pdf |
2008-08-04 |
| 5 |
4174-DELNP-2007-Correspondence-Others-(04-08-2008).pdf |
2008-08-04 |
| 6 |
4174-DELNP-2007-Assignment-(04-08-2008).pdf |
2008-08-04 |
| 7 |
4174-delnp-2007-pct-237.pdf |
2011-08-21 |
| 8 |
4174-delnp-2007-pct-220.pdf |
2011-08-21 |
| 9 |
4174-delnp-2007-pct-210.pdf |
2011-08-21 |
| 10 |
4174-delnp-2007-pct-101.pdf |
2011-08-21 |
| 11 |
4174-delnp-2007-form-5.pdf |
2011-08-21 |
| 12 |
4174-delnp-2007-form-3.pdf |
2011-08-21 |
| 13 |
4174-delnp-2007-form-2.pdf |
2011-08-21 |
| 14 |
4174-delnp-2007-form-18.pdf |
2011-08-21 |
| 15 |
4174-delnp-2007-form-1.pdf |
2011-08-21 |
| 16 |
4174-delnp-2007-drawings.pdf |
2011-08-21 |
| 17 |
4174-delnp-2007-description (complete).pdf |
2011-08-21 |
| 18 |
4174-delnp-2007-correspondence-others.pdf |
2011-08-21 |
| 19 |
4174-delnp-2007-correspondence-others 1.pdf |
2011-08-21 |
| 20 |
4174-delnp-2007-claims.pdf |
2011-08-21 |
| 21 |
4174-delnp-2007-abstract.pdf |
2011-08-21 |
| 22 |
4174-DELNP-2007_EXAMREPORT.pdf |
2016-06-30 |