DESCRIPTION
ANISOTROPIC CONDUCTIVE ADHESIVE, METHOD OF PRODUCING THE
SAME, CONNECTION STRUCTURE AND PRODUCING METHOD THEREOF
Technical Field
[0001]
The present invention relates to an anisotropic
conductive adhesive including a magnetic powder, as
conductive particles, dispersed in an insulating resin
composition.
Background Art
[0002]
An anisotropic conductive film is produced by
dispersing conductive particles in an insulating adhesive
and forming the resultant adhesive into a film shape. In
such a production process, since the pitch of wiring lines
is being reduced, conductive particles having smaller
diameters are being used. In addition, resin particles
coated with a nickel plating coating (hereinafter referred
to as nickel-coated resin particles) are widely used
because they have conductivity and defdrmability suitable
for anisotropic conductive connection and are available at
relatively low cost (Patent Literature 1).
Citation List
Patent Literature
[0003]
Patent Literature 1: Japanese Patent Application

Laid-Open No. 2009-259787
Summary of The Invention
Problems to be Solved by the Invention
[0004]
However, when an anisotropic conductive film using
conductive particles at least partially composed of a
magnetic material, for example, nickel particles or
nickel-coated resin particles, is used to establish an
anisotropic conductive connection between a semiconductor
chip and a circuit board, the insulating adhesive
component melts and flows during the process of
anisotropic conductive connection, and therefore also the
conductive particles easily move. This results in a
problem in that aggregation of the magnetic conductive
particles occurs. The occurrence of aggregation of the
conductive particles causes localization of the conductive
particles, and the risk of conduction failure or a short
circuit increases.
[0005]
It is an object of the present invention to solve
the foregoing problem in the conventional technology.
More specifically, an object of the invention is to, when
a paste-like or film-like anisotropic conductive adhesive
that uses conductive particles, for example, nickel-coated
resin particles, at least partially composed of a magnetic
material is used to establish an anisotropic conductive

connection, prevent the occurrence of aggregation of the
conductive particles in the anisotropic conductive
adhesive.
Means for Solving the Problems
[0006]
The present inventors have found that the above
object can be achieved by demagnetizing the conductive
particles, for example, nickel-coated resin particles, at
least partially composed of a magnetic material and to be
added to the anisotropic conductive adhesive before the
anisotropic conductive adhesive is used to establish an
anisotropic conductive connection. More specifically, the
present inventors have found that the above object can be
achieved by using conductive particles demagnetized in any
of the following manners: demagnetizing the conductive
particles in a powder form that have not been dispersed in
an insulating adhesive composition; demagnetizing the
conductive particles in a paste prepared by dispersing
them in the insulating adhesive composition; and
demagnetizing the conductive particles in a film formed
from the paste. Thus, the invention has been completed.
[0007]
Accordingly, the present invention provides an
anisotropic conductive adhesive including an insulating
adhesive composition and magnetic conductive particles
dispersed therein, wherein the magnetic conductive

particles have been subjected to demagnetization before
establishment of an anisotropic conductive connection
using the anisotropic conductive adhesive.
[0008]
The present invention also provides a method of
producing the above-described anisotropic conductive
adhesive including the insulating adhesive composition and
the magnetic conductive particles dispersed therein, the
method including demagnetizing the magnetic conductive
particles before the anisotropic conductive adhesive is
used to establish an anisotropic conductive connection.
[0009]
The present invention also provides a connection
structure including a first electronic component having a
terminal, a second electronic component having a terminal,
and the above-described anisotropic conductive adhesive,
wherein an anisotropic conductive connection between the
terminal of the first electronic component and the
terminal of the second electronic component has been
established using the anisotropic conductive adhesive.
[0010]
The present invention also provides a method of
producing a connection structure in which a terminal of a
first electronic component and a terminal of a second
electronic component has been connected, the method
including: disposing the above-described anisotropic

conductive adhesive between the terminal of the first
electronic component and the terminal of the second
electronic component; and pressing the first electronic
component against the second electronic component while
the anisotropic conductive adhesive is heated to thereby
establish an anisotropic conductive connection between the
terminals.
Advantageous Effects of the Invention
[0011]
In the anisotropic conductive adhesive of the
invention that uses magnetic conductive particles, the
magnetic conductive particles used have been demagnetized
before establishment of an anisotropic conductive
connection using the anisotropic conductive adhesive.
Therefore, when an anisotropic conductive connection is
established, aggregation of the magnetic conductive
particles can be prevented or significantly suppressed.
According to the present invention, the connection
reliability and insulation reliability of the anisotropic
conductive adhesive using the magnetic conductive
particles can be improved.
Brief Description of the Drawings
[0012]
FIG. 1 is a diagram illustrating a demagnetization
method that can be preferably used in the present
invention.

FIG. 2 is a diagram illustrating another
demagnetization method that can be preferably used in the
present invention.
FIG. 3 is a diagram illustrating another
demagnetization method that can be preferably used in the
present invention.
FIG. 4 is a diagram illustrating another
demagnetization method that can be preferably used in the
present invention.
Description of Embodiments
[0013]
The present invention will next be described in
detail.
[0014]
The anisotropic conductive adhesive of the present
invention includes an insulating adhesive composition and
magnetic conductive particles dispersed therein. The
feature of the anisotropic conductive adhesive is that the
magnetic conductive particles used have been demagnetized
before establishment of an anisotropic conductive
connection using the anisotropic conductive adhesive.
[0015]
(Magnetic conductive particles constituting anisotropic
conductive adhesive)
The magnetic conductive particles used in the
present invention are magnetizable conductive particles at

least partially composed of a magnetic material, as
described above. Therefore, the magnetic conductive
particles may have been magnetized or demagnetized.
Examples of such magnetic conductive particles include not
only conductive particles formed entirely of a single
magnetic material, but also particles prepared by forming
a thin film of a magnetic material on the surfaces of
conductive particles or insulating particles, particles
prepared by forming a non-magnetic metal film on the
above-described magnetic thin film, and particles prepared
by forming a thin film of a non-magnetic insulating resin
on the outermost surfaces of any of the above magnetic
powders.
[0016]
Specific examples of the magnetic powder that can be
used as the magnetic conductive particles include: powders
of magnetic metals and magnetic alloys such as nickel,
iron, iron oxide, chromium oxide, ferrite, cobalt, and
sendust; a powder such as metal-coated resin particles
prepared by forming a thin film of a magnetic material on
the surfaces of non-magnetic conductive particles such as
solder or copper particles or insulating resin core
particles; a powder prepared by further forming a gold-
plating thin film on the surfaces of any of the above
particles; and a powder prepared by coating any of the
above particles with an insulating resin layer.

[0017]
Of these, nickel-coated resin particles are
preferably used as the magnetic conductive particles for
anisotropic conductive connection, in consideration of
production cost, deformability under heating and
pressurization during the process of connection. No
particular limitation is imposed on the resin used as
cores. However, inorganic and organic materials having
heat resistance and chemical resistance can be preferably
used.
[0018]
For example, to suppress aggregation of nickel
particles used as the magnetic material constituting the
magnetic conductive particles, elemental phosphorus is
added to nickel when the nickel particles are produced.
In this case, the amount of elemental phosphorus added is
more than 0% by mass, preferably 1% by mass or more, and
more preferably 4% by mass or more. If the amount of
elemental phosphorus in nickel is excessively large, a
high-resistance connection is formed. Therefore, the
amount of elemental phosphorus is preferably 10% by mass
or less, and more preferably 8% by mass or less. The
elemental phosphorus in nickel is generally originated
from a phosphate compound, a phosphite compound, etc. used
to control the pH in a nickel plating bath, but this is
not a limitation.

[0019]
If the average particle diameter of the magnetic
conductive particles used in the present invention is
excessively small, the ratio of the amount of the magnetic
metal to the total amount of the magnetic conductive
particles becomes high, and the magnetic conductive
particles are easily affected by magnetism. Therefore,
aggregated clusters of the magnetic conductive particles
tend to be generated, and a short circuit may occur. In
addition, the anisotropic conduction function of the
conductive particles deteriorates, and the anisotropic
conductive adhesive may not be used for electric
components having terminals with large variations in
height, so that a problem with connection reliability
tends to occur. If the average particle diameter of the
magnetic conductive particles is excessively large, such
conductive particles tend to cause deterioration in
insulation between wiring lines, and the anisotropic
conductive adhesive may not be used for fine-pitch
connection. Therefore, the average particle diameter of
the magnetic conductive particles is preferably 0.5 to 30
µm, and more preferably 1 to 10 µm.
[0020]
No particular limitation is imposed on a method of
demagnetizing the magnetic conductive particles, and any
publicly known conventional demagnetization method may be

used. Particularly, since fine magnetic conductive
particles used for anisotropic conductive connection
easily move when a magnetic field for demagnetization
changes, the demagnetization efficiency of such particles
tends to deteriorate. Therefore, when such magnetic
conductive particles are demagnetized, it is preferable
that the magnetic conductive particles be subjected to
demagnetization with the relative positional relationship
between the magnetic conductive particles prevented from
being changed. The method described below can be
preferably used for demagnetization with the relative
positional relationship between the magnetic conductive
particles prevented from being changed.
[0021]
(Demagnetization method used for demagnetization of
magnetic conductive particles)
Various demagnetization methods can be used in the
present invention to demagnetize the magnetic conductive
particles before the anisotropic conductive adhesive is
used to establish an anisotropic conductive connection.
Preferred examples of such methods include a method in
which, before the anisotropic conductive adhesive is used
to establish an anisotropic conductive connection,
demagnetization is performed with the relative positional
relationship between the magnetic conductive particles
prevented from being changed. The phrase "with the

relative positional relationship between the magnetic
conductive particles prevented from being changed" means
that the magnetic field applied during demagnetization of
the magnetic conductive particles causes substantially no
relative positional change between the magnetic conductive
particles and almost no rotation of the magnetic
conductive particles so that the advantageous effects of
the invention are not greatly impaired. In other words,
so long as the advantageous effects of the invention are
not greatly impaired, the relative positional relationship
between the magnetic conductive particles may be slightly
changed during demagnetization.
[0022]
The methods of demagnetizing the magnetic conductive
particles with the above state maintained can be broadly
classified into a method in which the magnetic conductive
particles in a powder form are demagnetized and a method
in which the magnetic conductive particles in a paste or a
film are demagnetized. Examples of the method of
demagnetizing the particles in a powder form include the
following first and second modes. Examples of the method
of demagnetizing the particles in a paste include the
following third mode, and examples of the method of
demagnetizing the particles in a film include the
following fourth mode. The first, second, third, and
fourth modes of the demagnetization method

(demagnetization) will next be described in more detail.
Any publicly known demagnetization technique can be used.
[0023]

In the first mode, the magnetic conductive particles
in a powder form are subjected to demagnetization. The
powder form means a powder before dispersion in the
insulating adhesive composition.
[0024]
In the first mode, for example, the magnetic
conductive particles are charged into a container, and
these magnetic conductive particles in a powder form are
subjected to demagnetization. More specifically, as shown
in FIG. 1, in the first mode, the magnetic conductive
particles 1 are placed in a container 2 having an opening
2a and then pressed by pressing means 3 inserted into the
container 2 through the opening 2a of the container 2 to
temporarily fix the magnetic conductive particles in the
container 2. The container 2 is moved away from a
demagnetization coil 10 at least once in the direction
'indicated by an arrow in a demagnetization magnetic field
generated by the demagnetization coil 10 while the
intensity of the magnetic field is attenuated, whereby the
magnetic conductive particles in the powder form are
demagnetized. To improve the efficiency of
demagnetization, the container 2 may be reciprocated

(moved a plurality of times). The container 2 is not
limited to a container having an opening, and this method
can also be preferably used when the magnetic conductive
particles are charged into a container and then the
opening is vacuum sealed.
[0025]
The container that can be used in the first mode of
the demagnetization method and the second and third modes
of the demagnetization method described later is formed of
a non-magnetic material, a material having low magnetic
permeability, etc. Examples of such a container include a
glass container, an alumina container, and a porcelain
container. The container has preferably a tubular shape
and particularly preferably a cylindrical shape but may
have a polygonal tubular shape. The bottom of the
container is preferably rounded. The bottom may be
openable.
[0026]
No particular limitation is imposed on the pressing
means 3. For example, the pressing means 3 may be
configured such that a pusher 3b presses a hard or elastic
flat plate 3a. The level of pushing is set such that the
magnetic powder to be demagnetized is not damaged and the
movement of the magnetic powder can be suppressed during
demagnetization. The level of pushing can be determined
according to the type, size, and shape of the magnetic

powder, the conditions for demagnetization, etc.
[0027]

In the second mode, the magnetic conductive
particles in a powder form are subjected to
demagnetization, but the second mode is different from the
first mode. The powder form means a powder before
dispersion in the insulating adhesive composition.
[0028]
More specifically, as shown in FIG. 2, in the second
mode, the magnetic conductive particles 21 are added to a
liquid 22 contained in a container 23. Then the liquid 22
is solidified to temporarily fix the magnetic conductive
particles 21 in the solidified liquid, and the container
23 is moved away from a demagnetization coil 10 at least
once in the direction indicated by an arrow in a
demagnetization magnetic field generated by the
demagnetization coil 10 while the intensity of the
magnetic field is attenuated. The magnetic conductive
particles in the powder form are thereby demagnetized. To
improve the efficiency of demagnetization, the container
23 may be reciprocated (moved a plurality of times). Even
when the magnetic conductive particles in the solidified
liquid 22 are demagnetized as described above, the
magnetic conductive particles are not dispersed in the
insulating adhesive composition. Therefore, the magnetic

conductive particles are considered to be demagnetized in
a powder form because the magnetic conductive particles
return to their original state after the solidified liquid
is melted.
[0029]
In the second mode, the liquid is generally
solidified in the container 23, but the container may be
removed during demagnetization after solidification.
[0030]
In the second mode of the demagnetization method in
the present invention, it is preferable that, after the
magnetic conductive particles are added to the liquid, the
liquid be degassed and then solidified. This is because,
if the liquid is not degassed, bubbles are introduced into
the solidified liquid when the liquid is solidified and
magnetic conductive particles in the vicinity of the
bubbles can easily move.
[0031]
One specific method of solidifying the liquid is to
solidify the liquid by cooling it to lower than its
freezing point. Any of water, alcohols such as ethanol,
alkanes such as hexane and cyclohexane, aryls such as
toluene and naphthalene, etc. can be used as the liquid.
One specific example of solidification when water is used
as the liquid is to cool the liquid to 0°C or lower to
solidify the liquid. When cyclohexane (melting point: 7°C)

is used, the liquid is cooled to 7°C or lower and
preferably -10°C. In this case, after demagnetization, the
solidified liquid is left to stand or heated until the
temperature of the solidified liquid becomes its freezing
point or higher, and the demagnetized magnetic conductive
particles are separated from the liquid by a routine
method.
[0032]
In another method of solidifying the liquid, a
solidifying agent that can solidify the liquid is added to
the liquid, and the liquid is solidified with the aid of
the solidifying agent after the magnetic powder is added.
For example, in this method, a gelling agent for the
liquid is used as the solidifying agent. More
specifically, when the liquid is water, gelatin is used as
the solidifying agent, and the gelatin is dissolved in
water under heating. Then the magnetic powder is added
thereto, and degassing treatment is preformed if necessary.
Then the mixture is cooled to allow it to gelate. In this
case, the gel originating from gelatin disappears when
heated, and this phenomenon is reversible. Therefore,
after demagnetization, the solidified liquid is heated at
a temperature at which the gel disappears, and the
demagnetized magnetic conductive particles are separated
from the liquid by a routine method.
[0033]

In the third mode, the magnetic conductive particles
in a paste are subjected to demagnetization. The magnetic
conductive particles in a paste mean that they have been
dispersed in the insulating adhesive composition to form
the paste.
[0034]
More specifically, as shown in FIG. 3, in the third
mode, the paste 31 prepared by dispersing the magnetic
conductive particles in the insulating adhesive
composition is placed in a container 33 having an opening
32, and then the opening 32 of the container 33 is covered
with a cap, if necessary. The container 33 is moved away
from a demagnetization coil 10 at least once in the
direction indicated by an arrow in a magnetic field
generated by the demagnetization coil 10 while the
intensity of the magnetic field is attenuated, whereby the
magnetic conductive particles in the paste are
demagnetized. To improve the efficiency of
demagnetization, the container 33 may be reciprocated
(moved a plurality of times).
[0035]
In the third mode, if the viscosity of the
insulating adhesive composition after the magnetic
conductive particles are added thereto is too low, the
movement of the magnetic conductive particles is not

sufficiently suppressed. If the viscosity is too high,
the magnetic conductive particles tend to be difficult to
be dispersed. Therefore, the viscosity is preferably 1
Pa∙S to 10,000 Pa∙s.
[0036]
No particular limitation is imposed on a method of
dispersing the magnetic conductive particles in the
insulating adhesive composition, and any publicly known
dispersing method can be used.
[0037]

In the fourth mode, the magnetic conductive
particles in a film are subjected to demagnetization. The
magnetic conductive particles in a film mean that they
have been dispersed in the insulating adhesive composition
and the dispersion has been formed into a film by any
publicly known method.
[0038]
More specifically, as shown in FIG. 4, in the fourth
mode, a sheet of an anisotropic conductive film 42 is
placed on a non-magnetic base 41 and is pressed with a
non-magnetic cover 43 from above. Then the anisotropic
conductive film 42 is moved away from a demagnetization
coil 10 at least once in the direction indicated by an
arrow in a magnetic field generated by the demagnetization
coil 10 while the intensity of the magnetic field is

attenuated, whereby the magnetic conductive particles in
the film are demagnetized. In this case, an anisotropic
conductive film wound around a reel may be used instead of
the sheet of the anisotropic conductive film. To improve
the efficiency of demagnetization, the container 33 may be
reciprocated (moved a plurality of times).
[0039]
If the intensity of the magnetic field during
demagnetization using each of the above-described first to
fourth modes of the demagnetization method is too low, the
effects of demagnetization are not obtained, and the
conductive particles may aggregate. If the intensity of
the magnetic field is too high, the conductive particles
may be magnetized. Therefore, the suitable range of the
intensity of the magnetic field used is 100 to 2,000 G,
and the intensity of the magnetic field is preferably 200
to 2,000 G, and more preferably 200 to 400 G.
[0040]
If the demagnetization rate during demagnetization
using the demagnetization method in any of the
configurations in FIGs. 1 to 4 is too low, production
efficiency tends to be reduced. If the demagnetization
rate is too high, magnetic efficiency is difficult to be
obtained. Therefore, the demagnetization rate is
preferably 0.1 to 100 mm/s, more preferably 1 to 100 mm/s,
and still more preferably 1 to 50 mm/s.

[0041]
If the amount of the demagnetized magnetic
conductive particles described above contained in the
anisotropic conductive adhesive is too low, connection
reliability becomes insufficient. If the amount is too
high, anisotropy disappears. Therefore, the amount of the
demagnetized magnetic conductive particles is preferably 1
to 100 parts by mass and more preferably 2 to 70 parts by
mass based on 100 parts by mass of all the components (a
monomer, an oligomer, a non-polymerizable polymer, a
curing agent, etc.) used as film-forming components in the
insulating adhesive composition after curing.
[0042]
(Insulating adhesive composition constituting anisotropic
conductive adhesive)
The insulating adhesive composition constituting the
anisotropic conductive adhesive of the present invention
can be appropriately selected from thermosetting binder
resin compositions used for conventional anisotropic
conductive adhesives. Examples of the insulating adhesive
composition used include a composition prepared by adding
a curing agent such as an imidazoie-based or amine-based
curing agen-t to a thermosetting epoxy resin, a
thermosetting urea resin, a thermosetting melamine resin,
a thermosetting phenol resin, etc. Particularly, an
insulating adhesive composition prepared using a

thermosetting epoxy resin as a binder resin can be
preferably used, in consideration of its high bonding
strength after curing.
[0043]
Such a thermosetting epoxy resin may be in a liquid
form or a solid form. The epoxy equivalent of the
thermosetting epoxy resin is generally about 100 to about
4,000, and a thermosetting epoxy resin having at least two
epoxy groups in its molecule is preferred. Preferred
examples of the thermosetting epoxy resin that can be used
include bisphenol-A type epoxy compounds, phenol novolac
type epoxy compounds, cresol novolac type epoxy compounds,
ester type epoxy compounds, and alicyclic epoxy compounds.
These compounds include monomers and oligomers.
[0044]
If necessary, the insulating adhesive composition
may contain a filler such as silica or mica, a pigment, an
antistatic agent, etc. In addition, a colorant, a
preservative, a polyisocyanate-based crosslinking agent, a
silane coupling agent, a solvent, etc. may be added.
[0045]
(Preparation of anisotropic conductive adhesive)
In the anisotropic conductive adhesive of the
present invention, the conductive particles contained
therein and formed from a magnetic powder have been
subjected to demagnetization by any of the first to fourth

modes of the demagnetization method. However, except for
the above process, the anisotropic conductive adhesive can
be produced using the same method as that used for
conventional paste-like or film-like anisotropic
conductive adhesives.
[0046]
The anisotropic conductive adhesive of the present
invention can be used in the form of anisotropic
conductive paste but can be formed into a film shape using
a film-forming technique such as casting.
[0047]
(Connection structure)
The anisotropic conductive adhesive of the present
invention can be preferably used when an anisotropic
conductive connection is established between a terminal of
a first electronic component and a terminal of a second
electronic component. By establishing the anisotropic
conductive connection between the terminal of the first
electronic component and the terminal of the second
electronic component, a connection structure with the
anisotropic conductive connection is obtained. Such a
connection structure is also one aspect of the present
invention.
[0048]
Any of the publicly known electric elements such as
light-emitting elements, semiconductor chips and

semiconductor modules, flexible printed circuit boards,
glass circuit boards, glass epoxy boards, etc. can be used
as the first electronic component and the second
electronic component. The terminals may be traces,
electrode pads, or bumps formed of any of the publicly
known materials such as copper, gold, aluminum, or ITO,
and no particular limitation is imposed on their size.
[0049]
Specific preferred examples of the connection
structure of the present invention include so called COG
(chip on glass), COF (chip on film), FOG (film on glass),
and FOB (Film on Board) structures.
[0050]
(Method of producing connection structure)
The above-described connection structure can be
produced by disposing the above-described anisotropic
conductive adhesive between the terminal of the first
electronic component and the terminal of the second
electronic component and pressing the first electronic
component against the second electronic component while
the anisotropic conductive adhesive is heated to thereby
establish an anisotropic conductive connection between the
terminals. In this case, the pressing can be performed
using a metal-made pressing bonder or an elastic bonder.
The heating may be performed using heating means provided
in a stage on which the first electronic component or the

second electronic component is placed or may be performed
using a bonder provided with heating means.
Examples
[0051]
The present invention will next be specifically
described by way of Examples.
[0052]
Example 1 (Demagnetization using second mode of
demagnetization method)
(Demagnetization of conductive particles)
A chemical-resistant glass cylindrical container
having a volume of 900 mL, an opening inner diameter of 10
cm, and a depth of 20 cm was charged with 100 g of nickel-
coated resin particles having an average particle diameter
of 3 to 4 µm and prepared in a manner described later and
further charged with 500 g of cyclohexane, and the mixture
was dispersed and mixed.
[0053]
The cyclohexane mixture was cooled to -40°C and
solidified. The glass container containing the solidified
cyclohexane mixture was attached to a penetration-type
demagnetizer (a product of Sony Chemical & Information
Device Corporation) and subjected to demagnetization under
one of the conditions shown in TABLES 1 to 3. After
demagnetization, the glass container was brought to room
temperature, and the nickel-coated resin particles were

separated from cyclohexane by filtration, washed with
hexane, and dried to obtain demagnetized conductive
particles.
[0054]
(Preparation of nickel-coated resin particles)
A palladium catalyst was supported on 3 µm
divinylbenzene-based resin particles (5 g) by a dipping
method. Then the resin particles were subjected to
electroless nickel plating using an electroless nickel
plating solution (pH: 12, plating solution temperature:
50°C) prepared from nickel sulfate hexahydrate, sodium
hypophosphite, sodium citrate, triethanolamine, and
thallium nitrate. Varied types of nickel-coated resin
particles in which various nickel plating layers (metal
layers) containing varied amounts of phosphorus were
formed on their surfaces were obtained as conductive
particles. The average particle diameter of the obtained
conductive particles was in the range of 3 to 4 µm.
[0055]
(Production of anisotropic conductive film)
35 Parts by mass of one type of the demagnetized
nickel-coated resin particles used as conductive particles,
30 parts by mass of bisphenol A-type phenoxy resin (YP50,
NSCC Epoxy Manufacturing Co., Ltd.) used as a film-forming
component, 30 parts by mass of a bisphenol A epoxy
compound (EP828, Mitsubishi Chemical Corporation) used as

a liquid component, 39 parts by mass of an amine-based
curing agent (PHX3941HP, Asahi Kasei Corporation), and 1
part by mass of an epoxysilane coupling agent (A-187,
Momentive Performance Materials Inc.) were diluted with
toluene such that the amount of solids was 50% by mass and
were then mixed to prepare an anisotropic conductive
adhesive. The prepared adhesive was applied to a release-
treated polyethylene terephthalate film to a dry thickness
of 25 µm using a bar coater. The film was dried in an oven
at 80°C for 5 minutes to produce an anisotropic conductive
film.
[0056]
(Production of connection structure)
The produced anisotropic conductive film was
disposed between ITO electrodes of a glass circuit board
and gold bumps (height: 15 µm) formed on an IC chip of 13
mm x 1.5 mm and was pressed at 180°C and 40 MPa for 15
seconds using a flip-chip bonder to obtain a connection
structure.
[0057]
Comparative Example 1
(Production of anisotropic conductive film)
Anisotropic conductive adhesives were prepared as in
Example 1 except that non-demagnetized nickel-coated resin
particles were used instead of the demagnetized nickel-
coated resin particles. Then anisotropic conductive films

were produced, and connection structures were also
obtained.
[0058]
(Evaluation)
The "insulating properties" and "connection
resistances" of the obtained anisotropic conductive films
and connection structures were evaluated as described
below under the conditions of varied demagnetization rates
(TABLE 1) or under the conditions of varied phosphorus
amounts (TABLE 2).
[0059]

A short-circuit evaluation insulating TEG (a 13 mm x
1.5 mm IC chip having gold bumps (height: 15 (am) formed
thereon, bump size: 25 x 140 (am, space between bumps: 10
µm) having ITO traces arranged in a comb teeth shape on a
glass substrate was press-bonded to the bonding surface of
each of the anisotropic conductive films in Example 1 and
Comparative Example 1 using a bonder under the conditions
of an attained temperature of 180°C and a press bonding
time of 15 seconds. Here, the release-treated
polyethylene terephthalate film of the film had not been
peeled off and removed. The insulation resistance between
bumps was measured, and the number of formed short
circuits was counted. These were evaluated according to
the following evaluation criteria. The results obtained

are shown in TABLEs 1 and 2. A place at which a short
circuit had occurred was observed under an optical
microscope to check the presence or absence of aggregation
and the degree of aggregation according to the state of
clogging of the conductive particles etc.
[0060]
Rank Details
A: The number of formed short circuits was less than 10
out of 4 0 samples.
B: The number of formed short circuits was 10 or more
and less than 20 out of 40 samples.
C: The number of formed short circuits was 20 or more
out of 40 samples.
[0061]

The conduction resistance of each of the connection
structures obtained in Example 1 and Comparative Example 1
was measured by a four probe method immediately after
production. The results obtained are shown in TABLEs 1
and 2.
[0062]
Rank Details
A: The connection resistance value was less than 10 Ω.
B: The connection resistance value was 10 Ω or higher
and less than 50 Ω.
C: The connection resistance value was 50 Ω or higher.

[0065]

In Comparative Example 1 in which the non-
demagnetized conductive particles were used, the results
of evaluation of the insulating properties for varied
phosphorus amounts were "C" or "B".
However, in Example 1 in which the demagnetized
conductive particles were used, the results of evaluation
of the insulating properties for varied demagnetization
rates and for varied phosphorus amounts were basically "A"
or "B" although the evaluation of the insulating
properties was "C" under some extreme conditions. As can
be seen from these results, in the anisotropic conductive
adhesives and connection structures of the present
invention, the conductive particles being magnetic powder
used were efficiently demagnetized, and favorable
connection reliability and insulation reliability were
achieved. Findings about the tendency of demagnetization
conditions will next be described.
[0066]

(1) For varied demagnetization rates
As can be seen from TABLE 1, as the demagnetization
rate increases, the insulating properties tend to
deteriorate. However, the degree of deterioration is not

large.
(2) For varied phosphorus amounts
As can be seen from the results in TABLE 2, the
insulating properties do not deteriorate, so long as the
magnetic field intensity is 200 to 2,000 G irrespective of
the phosphorus amount. The results of the optical
microscopic observation showed that aggregation of the
conductive particles was observed in a place at which a
"short circuit" had occurred and the degree of aggregation
was particularly significant when the evaluation was "C".
[0067]

When demagnetization was not performed, the
connection resistance value was low. It is desirable that,
even when demagnetization is performed, an increase in the
connection resistance value do not occur. As can be seen
from the column of "connection resistance" in TABLES 1 and
2, a preferred connection resistance value could be
maintained even when the demagnetization rate or the
phosphorus amount was changed.
[0068]
Example 2 (Demagnetization using first mode of
demagnetization method)
A chemical-resistant glass cylindrical container
having a volume of 100 ml, an opening inner diameter of 60
mm, and a depth of 70 mm was charged with 100 g of (non-

demagnetized) nickel-coated resin particles having an
average particle diameter of 3 to 4 µm and prepared as in
Example 1. The surfaces of the resin particles were
located 20 mm from the opening. The nickel contained 4%
by mass of phosphorus atoms.
[0069]
Next, a disk-shaped glass plate having a diameter of
60 mm and a thickness of 10 mm was inserted from the
opening and placed on the surfaces of the resin particles.
The glass plate was pressed with a force of 500 N and
detachably secured. The glass container was attached to a
penetration-type demagnetizer (a product of Sony Chemical
& Information Device Corporation) and subjected to
demagnetization at a magnetic field intensity of 400 G, a
demagnetization rate of 50 mm/s, and room temperature.
[0070]
Anisotropic conductive adhesives, anisotropic
conductive films, and connection structures were produced
as in Example 1 except that the conductive particles
obtained in this Example were used. The obtained
anisotropic conductive films and connection structures
were tested and evaluated as in Example 1, and the
evaluation results showed the same tendency as in Example
1.
[0071]
Example 3 (Demagnetization using third mode of

demagnetization method)
(Preparation of anisotropic conductive adhesive)
35 Parts by mass of one type of the (non-
demagnetized) nickel-coated resin particles produced in
Example 1, having an average particle diameter of 3 to 4
µm, and used as conductive particles, 30 parts by mass of
bisphenol A-type phenoxy resin (YP50, NSCC Epoxy
Manufacturing Co., Ltd.) used as a film-forming component,
30 parts by mass of a bisphenol A epoxy compound (EP828,
Mitsubishi Chemical Corporation) used as a liquid
component, 39 parts by mass of an amine-based curing agent
(PHX3941HP, Asahi Kasei Corporation), and 1 part by mass
of an epoxysilane coupling agent (A-187, Momentive
Performance Materials Inc.) were diluted with toluene such
that the amount of solids was 50% by mass and a prescribed
viscosity (25°C) was obtained and were then mixed to
prepare a paste-like anisotropic conductive adhesive. The
nickel contained 4% by mass of phosphorus atoms.
[0072]
(Demagnetization of paste-like anisotropic conductive
adhesive)
The paste-like anisotropic conductive adhesive was
placed in a chemical-resistant glass cylindrical container
having a volume of 100 mL, an opening inner diameter of 60
mm, and a depth of 70 mm. The surface of the anisotropic
conductive adhesive was located 20 mm from the opening.

[0073]
Next, the glass container was attached to a
penetration-type demagnetizer (a product of Sony Chemical
& Information Device Corporation) and subjected to
demagnetization at a prescribed magnetic field intensity,
a demagnetization rate of 50 mm/s, and room temperature.
Paste-like anisotropic conductive adhesives containing
demagnetized conductive particles were thereby obtained.
[0074]
Anisotropic conductive films and connection
structures were produced as in Example 1 except that the
paste-like anisotropic conductive adhesives containing the
demagnetized conductive particles and obtained in this
Example were used. The obtained anisotropic conductive
films and connection structures were tested and evaluated
as in Example 1. The results obtained are shown in TABLE
3.
[0075]
Comparative Example 2
Paste-like anisotropic conductive adhesives were
prepared as in Example 3 except that the anisotropic
conductive adhesives were not demagnetized. Then
anisotropic conductive films were produced, and connection
structures were also obtained. The obtained anisotropic
conductive films and connection structures were tested and
evaluated as in Example 1. The results obtained are shown

in TABLE 3.

[0077]

In Comparative Example 2 in which the non-
demagnetized conductive particles were used, the results
of evaluation of the insulating properties for varied
anisotropic conductive adhesive viscosities were "C".
However, in Example 3 in which the conductive particles
demagnetized in the paste-like anisotropic conductive
adhesive were used, the results of evaluation of the
insulating properties for varied adhesive viscosities were
basically "A" or "B" although the evaluation of the
insulating properties was "C" under some extreme
conditions. As can be seen from these results, in the
paste-like anisotropic conductive adhesives and connection
structures of the present invention, the conductive
particles being magnetic powder used were efficiently
demagnetized, and favorable connection reliability and
insulation reliability were achieved. Findings about the
tendency of demagnetization conditions will next be
described.
[0078]

(1) For varied anisotropic conductive adhesive viscosities
As can be seen from TABLE 3, as the viscosity of the
adhesive decreases, the insulating properties tend to

deteriorate. However, the degree of deterioration is not
large. The results of the optical microscopic observation
showed that aggregation of the conductive particles was
observed in a place at which a "short circuit" had
occurred and the degree of aggregation was particularly
significant when the evaluation was "C".
[0079]

When demagnetization was not performed, the
connection resistance value was low. It is desirable that,
even when demagnetization is performed, an increase in the
connection resistance value do not occur. As can be seen
from the column of "connection resistance" in TABLE 3, a
preferred connection resistance value could be maintained
even when the adhesive composition viscosity was changed.
When the amount of phosphorus was changed, the same
tendency as in TABLE 2 was observed.
[0080]
Example 4 (Demagnetization using fourth mode of
demagnetization method)
(Preparation of anisotropic conductive adhesive)
35 Parts by mass of one type of the (non-
demagnetized) nickel-coated resin particles produced in
Example 1, having an average particle diameter of 3 to 4
µm, and used as conductive particles, 30 parts by mass of
bisphenol A-type phenoxy resin (YP50, NSCC Epoxy

Manufacturing Co., Ltd.) used as a film-forming component,
30 parts by mass of a bisphenol A epoxy compound (EP828,
Mitsubishi Chemical Corporation) used as a liquid
component, 39 parts by mass of an amine-based curing agent
(PHX3941HP, Asahi Kasei Corporation), and 1 part by mass
of an epoxysilane coupling agent (A-187, Momentive
Performance Materials Inc.) were diluted with toluene such
that the amount of solids was 50% by mass and were then
mixed to prepare an anisotropic conductive adhesive. The
nickel contained 4% by mass of phosphorus atoms.
[0081]
(Production of anisotropic conductive film)
The prepared anisotropic conductive adhesive was
applied to a release-treated polyethylene terephthalate
film to a dry thickness of 25 µm using a bar coater. The
film was dried in an oven at 80°C for 5 minutes to produce
an anisotropic conductive film.
[0082]
(Demagnetization in anisotropic conductive film)
Next, a stacked body obtained by sandwiching the
anisotropic conductive film between a non-magnetic base
and a cover was attached to a penetration-type
demagnetizer (a product of Sony Chemical & Information
Device Corporation) and subjected to demagnetization at a
prescribed magnetic field intensity, under varied
demagnetization rates, at room temperature. An

anisotropic conductive film containing demagnetized
conductive particles was thereby obtained.
[0083]
(Production of connection structure)
The produced anisotropic conductive film was
disposed between ITO electrodes of a glass circuit board
and gold bumps (height: 15 jam) formed on an IC chip of 13
mm x 1.5 mm and was pressed at 180°C and 40 MPa for 15
seconds using a flip-chip bonder to obtain a connection
structure.
[0084]
The obtained anisotropic conductive films and
connection structures were tested and evaluated as in
Example 1. The results obtained are shown in TABLE 4.
[0085]
Comparative Example 3
An anisotropic conductive adhesive was prepared as
in Example 4 except that non-demagnetized nickel-coated
resin particles were used instead of the demagnetized
nickel-coated resin particles. Then an anisotropic
conductive film was produced, and a connection structure
was also obtained. The obtained anisotropic conductive
film and connection structure were tested and evaluated as
in Example 4. The results obtained are shown in TABLE 4.

[0087]

In Comparative Example 3 in which the non-
demagnetized conductive film was used, the results of
evaluation of the insulating properties were "C". However,
in Example 4 in which the conductive particles in the
anisotropic conductive films were demagnetized, the
results of evaluation of the insulating properties for
varied demagnetization were basically "A" or "B". As can
be seen from these results, in the film-like anisotropic
conductive adhesivesand connection structures of the
present invention, the conductive particles being magnetic
powder used were efficiently demagnetized, and favorable
connection reliability and insulation reliability were
achieved. Findings about the tendency of demagnetization
conditions will next be described.
[0088]

(1) For varied demagnetization rates
As can be seen from TABLE 4, as the demagnetization
rate increases, the insulating properties tend to
deteriorate. However, the degree of deterioration is not
large. The results of the optical microscopic observation
showed that aggregation of the conductive particles was
observed in a place at which a "short circuit" had

occurred.
[0089]

When demagnetization was not performed, the
connection resistance value was low. It is desirable that,
even when demagnetization is performed, an increase in the
connection resistance value do not occur. As can be seen
from the column of "connection resistance" in TABLE 4, a
preferred connection resistance value could be maintained
even when the demagnetization rate was changed. When the
amount of phosphorus was changed, the same tendency as in
TABLE 2 was observed.
Industrial Applicability
[0090]
The anisotropic conductive adhesive of the present
invention uses, as conductive particles, a magnetic powder
at least partially composed of a magnetic material. The
magnetic powder is demagnetized before the anisotropic
conductive adhesive is used to establish an anisotropic
conductive connection. Therefore, aggregation of the
conductive particles can be prevented or significantly
suppressed during anisotropic conductive connection. The
anisotropic conductive adhesive is useful for anisotropic
conductive connection between an electric element and a
circuit board.
Reference Signs List

[0091]
1, 21 magnetic conductive particle
2, 23 container
2a, 32 opening
3 pressing means
10 demagnetization coil
22 liquid
31 paste
33 container
41 non-magnetic base
42 anisotropic conductive film
43 non-magnetic cover

WE CLAIMS
1. An anisotropic conductive adhesive
comprising: an insulating adhesive composition; and magnetic
conductive particles dispersed therein, wherein the magnetic
conductive particles in a powder form that have not been
dispersed in the insulating adhesive composition have been
subjected to demagnetization.
2. The anisotropic conductive adhesive according
to claim 1, wherein the magnetic conductive particles are
nickel-coated resin particles or nickel metal particles.
3. The anisotropic conductive adhesive according
to claim 3, wherein the magnetic conductive particles are
nickel-coated resin particles, and nickel in the nickel-coated
resin particles contains elemental phosphorus.
4. The anisotropic conductive adhesive according
to claim 4, wherein the nickel in the nickel-coated resin
particles contains 4 to 8% by mass of the elemental phosphorus.
5. The anisotropic conductive adhesive according
to any of claims 1 and 3 to 5, wherein the average particle

diameter of the magnetic conductive particles is 1 to 10 µm.
6. The anisotropic conductive adhesive according
to any of claims 1 and 3 to 6, wherein the demagnetization has
been performed on the magnetic conductive particles in a
powder form filled into a container and pressed by pressing
means inserted into the container to temporarily be fixed in
the container.
7. The anisotropic conductive adhesive according
to any of claims 1 and 3 to 6, wherein the demagnetization has
been performed on the magnetic conductive particles in a
powder form obtained by adding the magnetic conductive
particles to a liquid and solidifying the liquid to
temporarily fix the magnetic conductive particles in the
solidified liquid.
8. The anisotropic conductive adhesive according
to claim 8, wherein the demagnetization has been performed on
the magnetic conductive particles in the powder form obtained
by adding the magnetic conductive particles to a liquid, and
solidifying the liquid to temporarily fix the magnetic
conductive particles in the solidified liquid after degassing
treatment.

9. The anisotropic conductive adhesive according
to any of claims 1 and 3 to 9, wherein the anisotropic
conductive adhesive has been formed into a film shape.
10. The anisotropic conductive adhesive according
to any of claims 1 and 3 to 10, wherein the demagnetization of
the magnetic conductive particles has been performed at a
magnetic field intensity of 200 to 2,000 G.
11. The anisotropic conductive adhesive according
to any of claims 1, 3 to 10, and 12, wherein the
demagnetization of the magnetic conductive particles has been
performed at a demagnetization rate of 0.1 to 100 mm/s.
12. A connection structure comprising a first
electronic component having a terminal, a second electronic
component having a terminal, and the anisotropic conductive
adhesive according to any of claims 1, 3 to 10, 12, 13, and 16
to 22, wherein an anisotropic conductive connection between
the terminal of the first electronic component and the
terminal of the second electronic component has been
established using the anisotropic conductive adhesive.

13. A method of producing a connection structure
in which a terminal of a first electronic component and a
terminal of a second electronic component has been connected,
the method comprising: disposing the anisotropic conductive
adhesive according to any of claims 1, 3 to 10, 12, 13, and 16
to 22 between the terminal of the first electronic component
and the terminal of the second electronic component; and
pressing the first electronic component against the second
electronic component while the anisotropic conductive adhesive
is heated to thereby establish an anisotropic conductive
connection between the terminals.
14. An anisotropic conductive adhesive
comprising: an insulating adhesive composition; and magnetic
conductive particles dispersed therein, wherein the magnetic
conductive particles in a paste obtained by dispersing the
magnetic conductive particles in the insulating adhesive
composition, or the magnetic conductive particles in a film
formed using the paste have been subjected to demagnetization.
15. The anisotropic conductive adhesive according
to claim 16, wherein the magnetic conductive particles are
nickel-coated resin particles or nickel metal particles.
16 . The anisotropic conductive adhesive according

to claim 17, wherein the magnetic conductive particles are
nickel-coated resin particles, and nickel in the nickel-coated
resin particles contains elemental phosphorus.
17. The anisotropic conductive adhesive according
to claim 18, wherein the nickel in the nickel-coated resin
particles contains 4 to 8% by mass of the elemental phosphorus.
18. The anisotropic conductive adhesive according
to any of claims 16 to 19, wherein the average particle
diameter of the magnetic conductive particles is 1 to 10 µm.
19. The anisotropic conductive adhesive according
to any of claims 16 to 20, wherein the demagnetization of the
magnetic conductive particles has been performed at a magnetic
field intensity of 200 to 2,000 G.
20. The anisotropic conductive adhesive according
to any of claims 16 to 21, wherein the demagnetization of the
magnetic conductive particles has been performed at a
demagnetization rate of 0.1 to 100 mm/s.
21. An anisotropic conductive adhesive
comprising: an insulating adhesive composition; and magnetic
conductive particles dispersed therein, wherein:

the magnetic conductive particles in a powder form that
have not been dispersed in the insulating adhesive composition,
the magnetic conductive particles in a paste obtained by-
dispersing the magnetic conductive particles in the insulating
adhesive composition, or the magnetic conductive particles in
a film formed using the paste have been subjected to
demagnetization at a magnetic field intensity of 200 to 2,000
G;
the magnetic conductive particles are nickel-coated resin
particles;
the nickel in the nickel-coated resin particles contains
4 to 8% by mass of the elemental phosphorus; and
the average particle diameter of the magnetic conductive
particles is 1 to 10 µm.
22. An anisotropic conductive adhesive
comprising: an insulating adhesive composition; and magnetic
conductive particles dispersed therein, wherein:
the magnetic conductive particles in a powder form that
have not been dispersed in the insulating adhesive composition,
the magnetic conductive particles in a paste obtained by
dispersing the magnetic conductive particles in the insulating
adhesive composition, or the magnetic conductive particles in
a film formed using the paste have been subjected to
demagnetization at a magnetic field intensity of 200 to 2,000

G and at a demagnetization rate of 0.1 to 100 mm/s;
the magnetic conductive particles are nickel-coated resin
particles;
the nickel in the nickel-coated resin particles contains
4 to 8% by mass of the elemental phosphorus; and
the average particle diameter of the magnetic conductive
particles is 1 to 10 µm.
23. An anisotropic conductive adhesive
comprising: an insulating adhesive composition; and magnetic
conductive particles dispersed therein, wherein:
the magnetic conductive particles in a powder form that
have not been dispersed in the insulating adhesive composition,
the magnetic conductive particles in a paste obtained by
dispersing the magnetic conductive particles in the insulating
adhesive composition, or the magnetic conductive particles in
a film formed using the paste have been subjected to
demagnetization at a magnetic field intensity of 200 to 400 G
and at a demagnetization rate of 1 to 50 mm/s;
the magnetic conductive particles are nickel-coated resin
particles; and
the nickel in the nickel-coated resin particles contains
4 to 8% by mass of the elemental phosphorus.
24. A method of producing an anisotropic

conductive adhesive including an insulating adhesive
composition and magnetic conductive particles dispersed
therein, the method comprising: filling the magnetic
conductive particles in a container; pressing the magnetic
conductive particles by pressing means inserted into the
container to temporarily fix the magnetic conductive
particles; subjecting the magnetic conductive particles in a
powder form to demagnetization; and dispersing the
demagnetized magnetic conductive particles in the insulating
adhesive composition.
25. A method of producing an anisotropic
conductive adhesive including an insulating adhesive
composition and magnetic conductive particles dispersed
therein, the method comprising: adding the magnetic conductive
particles to a liquid, and solidifying the liquid to
temporarily fix the magnetic conductive particles in the
solidified liquid; subjecting the magnetic conductive
particles in a powder form to demagnetization; and dispersing
the demagnetized magnetic conductive particles in the
insulating adhesive composition.
26. The production method according to claim 27,
wherein the magnetic conductive particles are added to the
liquid, and the liquid is solidified after degassing treatment.

27. The production method according to any of
claims 2 6 to 28, wherein the magnetic conductive particles are
nickel-coated resin particles.
28. The production method according to claim 29,
wherein the nickel in the nickel-coated resin particles
contains 4 to 8% by mass of the elemental phosphorus.
29. The production method according to any of
claims 26 to 30, wherein the average particle diameter of the
magnetic conductive particles is 1 to 10 µm.
30. The production method according to any of
claims 2 6 to 31, wherein the demagnetization of the magnetic
conductive particles has been performed at a magnetic field
intensity of 200 to 2,000 G.
31. The production method according to any of
claims 26 to 32, wherein the demagnetization of the magnetic
conductive particles has been performed at a demagnetization
rate of 0.1 to 100 mm/s.