U.S. patent application number 14/904443 was filed with the patent office on 2016-05-26 for method for manufacturing electrically conductive adhesive film, electrically conductive adhesive film, and method for manufacturing connector.
This patent application is currently assigned to DEXERIALS CORPORATION. The applicant listed for this patent is DEXERIALS CORPORATION. Invention is credited to Yasushi AKUTSU.
Application Number | 20160149366 14/904443 |
Document ID | / |
Family ID | 52431701 |
Filed Date | 2016-05-26 |
United States Patent
Application |
20160149366 |
Kind Code |
A1 |
AKUTSU; Yasushi |
May 26, 2016 |
METHOD FOR MANUFACTURING ELECTRICALLY CONDUCTIVE ADHESIVE FILM,
ELECTRICALLY CONDUCTIVE ADHESIVE FILM, AND METHOD FOR MANUFACTURING
CONNECTOR
Abstract
An anisotropic conductive film is capable of preventing a short
circuit between terminals even though narrowing of the interval
between connecting terminals advances. An electrically conductive
support plate supports a base film having one surface with an
adhesive layer. An array plate is disposed to face the adhesive
layer and has through holes arranged in a pattern corresponding to
the array pattern of electrically conductive particles. A spray
sprays the electrically conductive particles together with a liquid
while applying a voltage to the electrically conductive particles,
in which the electrically conductive particles which are charged
with an electrical charge are sprayed together with a liquid from
the spray while applying a voltage between the spray and the
support plate and the electrically conductive particles which have
passed through the through holes of the array plate are arranged on
the adhesive layer in the array pattern of the through holes.
Inventors: |
AKUTSU; Yasushi;
(Utsunomiya-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DEXERIALS CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
DEXERIALS CORPORATION
Tokyo
JP
|
Family ID: |
52431701 |
Appl. No.: |
14/904443 |
Filed: |
July 28, 2014 |
PCT Filed: |
July 28, 2014 |
PCT NO: |
PCT/JP2014/069794 |
371 Date: |
January 12, 2016 |
Current U.S.
Class: |
156/302 ;
427/468; 428/206 |
Current CPC
Class: |
H01R 43/205 20130101;
H05K 3/143 20130101; C09J 2301/122 20200801; H01R 12/62 20130101;
C09J 9/02 20130101; H01R 4/04 20130101; C08K 7/18 20130101; H05K
2201/0224 20130101; H01R 43/007 20130101; C08K 3/08 20130101; C09J
2203/326 20130101; H05K 3/323 20130101; C08K 3/04 20130101; C09J
2301/314 20200801; C09J 7/20 20180101; H05K 2203/1344 20130101 |
International
Class: |
H01R 43/20 20060101
H01R043/20; C09J 7/02 20060101 C09J007/02; C09J 9/02 20060101
C09J009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 29, 2013 |
JP |
2013-157099 |
Claims
1. A method for manufacturing an electrically conductive adhesive
film, the method comprising steps of: providing an electrically
conductive support plate to support a first base film having an
adhesive layer formed on a surface; providing an array plate that
is disposed to face the adhesive layer of the first base film
supported by the support plate and has a plurality of through holes
arranged in a pattern corresponding to an array pattern of
electrically conductive particles formed thereon; providing a spray
that is disposed on a side opposite to a side facing the support
plate of the array plate and sprays electrically conductive
particles together with a liquid while applying a voltage to the
electrically conductive particles; spraying the electrically
conductive particles charged with an electrical charge together
with a liquid from the spray while applying a voltage between the
spray and the support plate supporting a surface on the opposite
side to a surface on which the adhesive layer is formed of the
first base film; and arranging the electrically conductive
particles which passed through the through holes of the array plate
on the adhesive layer in an array pattern of the through holes.
2. The method for manufacturing an electrically conductive adhesive
film according to claim 1, wherein a surface of the electrically
conductive particles is covered with an insulating material.
3. The method for manufacturing an electrically conductive adhesive
film according to claim 2, wherein a thickness of an insulating
film to cover the surface of the electrically conductive particles
is from 0.1 to 50% of a particle size of the electrically
conductive particles.
4. The method for manufacturing an electrically conductive adhesive
film according to claim 1, wherein the array plate is prevented
from being charged.
5. The method for manufacturing an electrically conductive adhesive
film according to claim 1, wherein a size of the through holes
formed on the array plate is from 120 to 200% of the size of the
electrically conductive particles.
6. The method for manufacturing an electrically conductive adhesive
film according to claim 1, wherein the support plate is formed in a
roll shape and arrangement of the electrically conductive particles
on the adhesive layer is continuously conducted while conveying the
base film.
7. The method for manufacturing an electrically conductive adhesive
film according to claim 1, wherein a second base film is laminated
on the adhesive layer after the electrically conductive particles
are arranged on the adhesive layer.
8. An electrically conductive adhesive film comprising: a base
film; a binder resin laminated on the base film; and electrically
conductive particles regularly dispersed and disposed on the binder
resin in a predetermined array pattern, wherein electrically
conductive particles having abrasions on a surface among the
plurality of electrically conductive particles are 0.5% or more and
within 30% of a total particle number.
9. The electrically conductive adhesive film according to claim 8,
wherein an aggregate of the plurality of the electrically
conductive particles is within 15% of a total particle number.
10. An electrically conductive adhesive film comprising: a base
film; a binder resin laminated on the base film; and electrically
conductive particles regularly dispersed and disposed on the binder
resin in a predetermined array pattern, wherein electrically
conductive particles having abrasions on a surface among the
plurality of electrically conductive particles are 0.5% or more and
within 30% of a total particle number, wherein the electrically
conductive adhesive film is manufactured using the method for
manufacturing an electrically conductive adhesive film according to
claim 1.
11. A method for manufacturing a connector obtained by connecting a
plurality of terminals arranged in parallel to one another by an
anisotropic conductive film having electrically conductive
particles arranged therein, wherein the anisotropic conductive film
is manufactured by steps of: providing an electrically conductive
support plate to support a base film having an adhesive layer
formed on a surface; providing an array plate that is disposed to
face the adhesive layer of the base film supported by the support
plate and has a plurality of through holes arranged in a pattern
corresponding to an array pattern of electrically conductive
particles formed thereon; providing a spray that is disposed above
the array plate and sprays electrically conductive particles
together with a liquid while applying a voltage to the electrically
conductive particles; spraying the electrically conductive
particles charged with an electrical charge together with a liquid
from the spray while applying a voltage between the spray and the
support plate to support the base film in a state in which the
adhesive layer is turned upward; and arranging the electrically
conductive particles which passed through the through holes of the
array plate on the adhesive layer in an array pattern of the
through holes.
Description
TECHNICAL FIELD
[0001] The present invention relates to an electrically conductive
adhesive, particularly relates to a method for manufacturing an
electrically conductive adhesive film that is suitably usable in
anisotropic conductive connection, an electrically conductive
adhesive film manufactured by using this manufacturing method, and
a method for manufacturing a connector using this electrically
conductive adhesive film.
[0002] This application is based upon and claims the benefit of
priority of the prior Japanese Patent Application No. 2013-157099
filed in the Japan Patent Office on Jul. 29, 2013, the entire
contents of which are incorporated herein by reference.
BACKGROUND ART
[0003] Hitherto, an anisotropic conductive film obtained by molding
a binder resin in which electrically conductive particles are
dispersed into a film is used as an adhesive when connecting a
rigid substrate such as a glass substrate or a glass epoxy
substrate to a flexible substrate or an IC chip or when connecting
flexible substrates to each other. When the case of connecting the
connecting terminal of a flexible substrate to the connecting
terminal of a rigid substrate is described as an example, as
illustrated in FIG. 7(A), an anisotropic conductive film 53 is
disposed between the regions in which both connecting terminals 52
and 55 of a flexible substrate 51 and a rigid substrate 54 are
formed, a buffer material 50 is appropriately disposed on the
flexible substrate 51, and the substrates 51 and 54 are
heat-pressurized from the top of the flexible substrate 51 by a
heating and pressing head 56. By virtue of this, as illustrated in
FIG. 7(B), the binder resin becomes fluid to flow out from between
the connecting terminal 52 of the flexible substrate 51 and the
connecting terminal 55 of the rigid substrate 54 and also the
electrically conductive particles in the anisotropic conductive
film 53 are pressed and deformed by being sandwiched between the
two connecting terminals.
[0004] As a result, the connecting terminal 52 of the flexible
substrate 51 and the connecting terminal 55 of the rigid substrate
54 are electrically connected to each other via the electrically
conductive particles, and the binder resin is cured in this state.
The electrically conductive particles that are not present between
the two connecting terminals 52 and 55 are dispersed in the binder
resin and maintained in the electrically isolated state. By virtue
of this, it is possible to achieve electrical conduction only
between the connecting terminal 52 of the flexible substrate 51 and
the connecting terminal 55 of the rigid substrate 54.
CITATION LIST
Patent Literatures
[0005] Patent Literature 1: JP 04-251337 A
[0006] Patent Literature 2: JP 2010-251337 A
[0007] Patent Literature 3: JP 4789738 B1
SUMMARY OF INVENTION
Technical Problem
[0008] In recent years, high density mounting of electronic
components has advanced in association with the miniaturization and
thinning mainly of small-sized portable electronic devices such as
a mobile phone or a smart phone, a tablet PC, and a notebook
computer, and the microminiaturization of the connecting terminals
and the narrowing of the interval between the adjacent connecting
terminals have advanced in a so-called FOB (Film on Board)
connection to connect a flexible substrate to a main substrate or a
so-called FOF (Film on Film) connection to connect flexible
substrates to each other. In addition, the microminiaturization of
the connecting terminals due to an increase in terminals associated
with high definition of the screen and miniaturization of the
control IC and the narrowing of the interval between the adjacent
connecting terminals have advanced in a so-called COG (Chip on
Glass) connection to connect the control IC of a liquid crystal
screen to the ITO wiring of a glass substrate.
[0009] As such microminiaturization of the connecting terminals
associated with the requirement of high density mounting and the
narrowing of the interval between connecting terminals advance, it
is concerned that the electrically conductive particles are linked
to one another between the micro terminals to cause a short circuit
between the terminals since the electrically conductive particles
are randomly dispersed in the binder resin in the anisotropic
conductive film of prior art.
[0010] In order to cope with such a problem, a decrease in particle
size of the electrically conductive particles and a method to form
an insulating film on the particle surface have been proposed, but
it is concerned that the particle capture rate on the
microminiaturized connecting terminal decreases when the particle
size of the electrically conductive particles decreases, and it is
not possible to completely prevent the short circuit between the
terminals in the case of forming the insulating film. Furthermore,
as illustrated in FIG. 8(A), a method to separate the electrically
conductive particles 57 from one another through biaxial stretching
has also been proposed, but not all of the electrically conductive
particles are separated, as illustrated in FIG. 8(B), the aggregate
of particles 58 in which a plurality of electrically conductive
particles 57 are linked to one another remains, and thus it is not
possible to completely prevent a short circuit between the
terminals generated between the adjacent terminals 55, 55.
[0011] Accordingly, an object of the invention is to provide a
method for manufacturing an electrically conductive adhesive film
which can capture electrically conductive particles in a
microminiaturized connecting terminal as well as prevent a short
circuit between terminals even though microminiaturization of the
connecting terminal and the narrowing of the interval between
connecting terminals advance and thus can meet the requirement of
high density mounting, an electrically conductive adhesive film,
and a method for manufacturing a connector.
Solution to Problem
[0012] In order to solve the above problem, a method for
manufacturing an electrically conductive adhesive film according to
the invention is a method which includes steps of providing an
electrically conductive support plate to support a first base film
having an adhesive layer formed on a surface, providing an array
plate that is disposed to face the adhesive layer of the first base
film supported by the support plate and has a plurality of through
holes arranged in a pattern corresponding to an array pattern of
electrically conductive particles formed thereon, providing a spray
that is disposed on a side opposite to a side facing the support
plate of the array plate and sprays electrically conductive
particles together with a liquid while applying a voltage to the
electrically conductive particles, spraying the electrically
conductive particles charged with an electrical charge together
with a liquid from the spray while applying a voltage between the
spray and the support plate supporting a surface on the opposite
side to a surface on which the adhesive layer is formed of the
first base film, and arranging the electrically conductive
particles which passed through the through holes of the array plate
on the adhesive layer in an array pattern of the through holes.
[0013] In addition, an electrically conductive adhesive film
according to the invention is one that is manufactured by the
manufacturing method described above.
[0014] In addition, a method for manufacturing a connector
according to the invention is a method for manufacturing a
connector obtained by connecting a plurality of terminals arranged
in parallel to one another by an anisotropic conductive film having
electrically conductive particles arranged therein, in which the
anisotropic conductive film is manufactured by steps of: providing
an electrically conductive support plate to support a base film
having an adhesive layer formed on a surface; providing an array
plate that is disposed to face the adhesive layer of the base film
supported by the support plate and has a plurality of through holes
arranged in a pattern corresponding to an array pattern of
electrically conductive particles formed thereon; providing a spray
that is disposed above the array plate and sprays electrically
conductive particles together with a liquid while applying a
voltage to the electrically conductive particles; spraying the
electrically conductive particles charged with an electrical charge
together with a liquid from the spray while applying a voltage
between the spray and the support plate to support the base film in
a state in which the adhesive layer is turned upward; and arranging
the electrically conductive particles which passed through the
through holes of the array plate on the adhesive layer in an array
pattern of the through holes.
Advantageous Effects of Invention
[0015] According to the invention, it is possible to equally
disperse and dispose the electrically conductive particles on the
adhesive layer since the electrically conductive particles are
arranged in a desired pattern in advance, and this makes it
possible to provide an electrically conductive adhesive film which
can capture the electrically conductive particles in the
microminiaturized connecting terminal as well as prevent a short
circuit between terminals even though microminiaturization of the
connecting terminal and the narrowing of the interval between
connecting terminals advance and thus can meet the requirement of
high density mounting.
BRIEF DESCRIPTION OF DRAWINGS
[0016] FIG. 1 is a cross-sectional view illustrating an anisotropic
conductive film to which the invention is applied.
[0017] FIG. 2 is a cross-sectional view illustrating electrically
conductive particles used in the invention.
[0018] FIG. 3 is cross-sectional view illustrating a step of
arranging the electrically conductive particles in the
manufacturing process of an anisotropic conductive film.
[0019] FIGS. 4(A) to 4(C) are cross-sectional views illustrating a
step of laminating after the electrically conductive particles are
arranged.
[0020] FIG. 5 is a perspective view illustrating a state in which
an anisotropic conductive film is pasted to a rigid substrate
having a plurality of connecting terminals arranged in
parallel.
[0021] FIG. 6 is a cross-sectional view illustrating a
manufacturing process using a roll-shaped support plate.
[0022] FIGS. 7(A) and 7(B) are cross-sectional views illustrating
the manufacturing process of a connector using an anisotropic
conductive film of prior art, in which FIG. 7(A) illustrates the
state before pressure joining, and FIG. 7(B) illustrates the state
after pressure joining.
[0023] FIGS. 8(A) and 8(B) are views illustrating a technique to
separate the interval between the electrically conductive particles
by biaxial stretching, in which FIG. 8(A) illustrates the state of
the electrically conductive particles before being stretched, and
FIG. 8(B) illustrates the state that the aggregate of particles
remains after stretching.
DESCRIPTION OF EMBODIMENTS
[0024] Hereinafter, the method for manufacturing an electrically
conductive adhesive film, an electrically conductive adhesive film,
and a method for manufacturing a connector to which the invention
is applied will be described in detail with reference to the
accompanying drawings. Incidentally, the invention is not intended
to be limited only to the following embodiments, but it should be
understood that the various changes, substitutions, and alterations
could be made hereto without departing from the spirit and scope of
the invention. In addition, the drawings are schematic, and the
ratio and the like of the respective dimensions may be different
from the reality. The specific dimensions and the like should be
judged in consideration of the following description. Moreover, it
should be understood that the drawings include portions in which
the relationships and ratios of the dimensions are different from
one another.
[0025] [Anisotropic Conductive Film]
[0026] The electrically conductive adhesive film to which the
invention is applied is suitably used as an anisotropic conductive
film 1 for achieving conduction between connecting terminals as
electrically conductive particles are equally dispersed and
disposed on a binder resin to be an adhesive in a predetermined
pattern and the electrically conductive particles are sandwiched
between the connecting terminals facing each other. In addition, as
the connector using an electrically conductive adhesive film to
which the invention is applied is, for example, a connector in
which an IC or a flexible substrate is COG, FOB, or FOF connected
using the anisotropic conductive film 1 and another connector, and
the connector can be suitably used in any devices such as
television, or PC, mobile phones, game machines, audio devices, and
tablet terminators, or vehicle-mounted monitors.
[0027] The anisotropic conductive film 1 is a thermosetting
adhesive or a photocurable adhesive such as an ultraviolet curable
adhesive, is fluidized by being heated and pressurized by a
pressure tool (not illustrated) so that the electrically conductive
particles are pressed and deformed between the connecting terminals
facing to each other, and is cured by being heated or irradiated
with ultraviolet rays in a state in which the electrically
conductive particles are pressed and deformed. By virtue of this,
the anisotropic conductive film 1 electrically and mechanically
connects an IC or a flexible substrate to a connecting target such
as a glass substrate.
[0028] The anisotropic conductive film 1 is one, for example, as
illustrated in FIG. 1, in which electrically conductive particles 3
are disposed on an ordinary binder resin 2 (adhesive) containing a
film-forming resin, a thermosetting resin, a latent curing agent, a
silane coupling agent, and the like in a predetermined pattern and
this thermosetting adhesive composition is supported by first and
second base films 4 and 5 of an upper and lower pair.
[0029] The first and second base films 4 and 5 are formed, for
example, by coating a release agent such as silicone on PET (Poly
Ethylene Terephthalate), OPP (Oriented Polypropylene), PMP
(Poly-4-methylpentene-1), PTFE (Polytetrafluoroethylene), and the
like.
[0030] As the film forming resin contained in the binder resin 2, a
resin having an average molecular weight of about from 10000 to
80000 is preferable. Examples of the film forming resin may include
various kinds of resins such as an epoxy resin, a modified epoxy
resin, a urethane resin, and a phenoxy resin. Among them, a phenoxy
resin is even more preferable from the viewpoint of the film formed
state, connection reliability, and the like.
[0031] The thermosetting resin is not particularly limited, and
examples thereof may include an epoxy resin and an acrylic resin
that are commercially available.
[0032] The epoxy resin is not particularly limited, and examples
thereof may include a naphthalene type epoxy resin, a biphenyl type
epoxy resin, a phenol novolak type epoxy resin, a bisphenol type
epoxy resin, a stilbene type epoxy resin, a triphenol methane type
epoxy resin, a phenol aralkyl type epoxy resin, a naphthol type
epoxy resin, a dicyclopentadiene type epoxy resin, and a
triphenylmethane type epoxy resin. These may be a single substance
or a combination of two or more kinds thereof.
[0033] The acrylic resin is not particularly limited, and an
acrylic compound, a liquid acrylate, and the like can be
appropriately selected depending on the purpose. Examples thereof
may include methyl acrylate, ethyl acrylate, isopropyl acrylate,
isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate,
diethylene glycol diacrylate, trimethylol propane triacrylate,
dimethylol tricyclodecane diacrylate, tetramethylene glycol
tetraacrylate, 2-hydroxy-1,3-diacryloxypropane,
2,2-bis[4-(acryloxymethoxy)phenyl]propane,
2,2-bis[4-(acryloxyethoxy)phenyl]propane, dicyclopentenyl acrylate,
tricyclodecanyl acrylate, tris(acryloxyethyl)isocyanurate, urethane
acrylate, and epoxy acrylate. In addition, it is also possible to
use those in which acrylate is converted to methacrylate. These may
be used singly or two or more kinds thereof may be used
concurrently.
[0034] The latent curing agent is not particularly limited, and
examples thereof may include various kinds of curing agents of a
heat curing type, a UV curing type, and the like. The latent curing
agent does not react under a normal condition, but it is activated
by various kinds of triggers which are selected depending on the
application, such as heat, light, and pressurization and starts to
react. As the method for activating a thermally activated latent
curing agent, there are a method in which active species (a cation
or an anion, and a radical) are produced through the dissociation
reaction caused by heating, and the like, a method in which the
latent curing agent is stably dispersed in an epoxy resin at around
room temperature, but at a higher temperature, it is compatible
with and dissolves in the epoxy resin to start the curing reaction,
a method in which a molecular sieve encapsulation type curing agent
is eluted at a high temperature to start the curing reaction, a
method of elution and curing by a microcapsule, and the like.
Examples of the thermally activated latent curing agent may include
imidazole-based one, hydrazide-based one, a boron trifluoride-amine
complex, a sulfonium salt, an amine imide, a polyamine salt,
dicyandiamide, and any modified product thereof, and these may be a
single substance or a mixture of two or more kinds thereof. Among
them, the microcapsule type imidazole-based latent curing agent is
preferable.
[0035] The silane coupling agent is not particularly limited, and
examples thereof may include epoxy-based one, amino-based one,
mercapto and sulfide-based one, and ureido-based one. The adhesive
property at the interface between an organic material and an
inorganic material is improved by adding a silane coupling
agent.
[0036] [Electrically Conductive Particles]
[0037] Examples of the electrically conductive particles 3 may
include particles of various kinds of metals such as nickel, iron,
copper, aluminum, tin, lead, chromium, cobalt, silver, and gold, or
particles of a metal alloy, a metal oxide, those obtained by
coating a metal on the surface of particles of carbon, graphite,
glass, a ceramic, a plastic, or the like. In the case of those
obtained by coating a metal on the surface of resin particles,
examples of the resin particles may include particles of an epoxy
resin, a phenolic resin, an acrylic resin, an acrylonitrile-styrene
(AS) resin, a benzoguanamine resin, a divinylbenzene-based resin,
and a styrene-based resin.
[0038] As illustrated in FIG. 2, an insulating film 3a is formed as
the surface of the electrically conductive particles 3 is covered
with an insulating material. This makes it possible for the
electrically conductive particles 3 to charge the insulating film
3a with an electrical charge.
[0039] Examples of the insulating material constituting the
insulating film 3a may include various polymers such as an acrylic
polymer, a urethane-based polymer, an epoxy-based polymer, an
imide-based polymer, and an amide-based polymer. In addition,
examples of the method for forming the insulating film may include
a "hybridization treatment". The hybridization treatment is to
composite fine particles with fine particles and is one in which
the fixation and film forming treatment of particles are conducted
by applying mechanical heat energy mainly composed of an impact
force to the particles while dispersing the mother particles and
the child particles in the gas phase.
[0040] [Film Thickness of Insulating Film]
[0041] In addition, it is preferable that the insulating film 3a is
formed to have a film thickness of from 0.1 to 50% of the particle
size of the electrically conductive particles 3. As to be described
later, the electrically conductive particles 3 are required to be
arranged on the binder resin 2 in a state of being charged, and
thus it is concerned that the electrostatic property of the
insulating film 3a is lost before the electrically conductive
particles 3 are attached to the binder resin 2 when the thickness
of the insulating film 3a that is charged with an electrical charge
is thin and it is not possible to arrange the electrically
conductive particles 3 in a predetermined pattern. On the other
hand, the conduction resistance between the connecting terminals
increases when the insulating film 3a of the electrically
conductive particles 3 is too thick. Hence, it is preferable to
form the insulating film 3ain a thickness of from 0.1 to 50% of the
particle size of the electrically conductive particles 3.
[0042] Specifically, the film thickness of the insulating film 3a
can be decided based on the dielectric constant of the material
constituting the insulating film 3a. For example, in the case of
using (material name: polymethyl methacrylate, dielectric constant:
3) as the insulating film 3a that is formed on the surface of the
electrically conductive particles 3 having an average particle size
of 4 .mu.m, the film thickness can be set to approximately from
0.004 to 2.0 .mu.m.
[0043] In the anisotropic conductive film 1, as to be described
later, the electrically conductive particles 3 are regularly
arranged in a predetermined array pattern and thus the occurrence
of coarseness and fineness due to aggregation of the electrically
conductive particles is prevented. Hence, according to the
anisotropic conductive film 1, it is possible to prevent a short
circuit between terminals by aggregates of the electrically
conductive particles even though the narrowing of the interval
between connecting terminals advances, it is also possible to
capture the electrically conductive particles even in a
microminiaturized connecting terminal and thus to meet the
requirement of high density mounting.
[0044] Incidentally, the shape of the anisotropic conductive film 1
is not particularly limited, and for example, it may have a long
tape shape capable of being wound around a take-up reel 6 as
illustrated in FIG. 1 so that it may be cut by a predetermined
length for use.
[0045] In addition, in the embodiment described above, the
anisotropic conductive film 1 has been described by taking an
adhesive film obtained by molding a thermosetting resin composition
containing the electrically conductive particles 3 in the binder
resin 2 in a film shape as an example, but the adhesive according
to the invention is not limited thereto, and for example, it may
have a configuration in which an insulating adhesive layer composed
of only the binder resin 2 and an electrically conductive
particle-containing layer composed of the binder resin 2 containing
the electrically conductive particles 3 are laminated.
[0046] [Method for Manufacturing Anisotropic Conductive Film]
[0047] Next, the method for manufacturing the anisotropic
conductive film 1 will be described. The manufacturing process of
the anisotropic conductive film 1 includes a step of arranging the
electrically conductive particles 3 on the binder resin 2 formed on
one surface of the first base film 4 in a predetermined pattern.
The electrically conductive particles 3 arranged on the binder
resin 2 are pushed into the binder resin 2 as the second base film
5 is laminated on the surface on which the electrically conductive
particles 3 are arranged of the binder resin 2.
[0048] In the step of arranging the electrically conductive
particles, as illustrated in FIG. 3, an electrically conductive
support plate 10 to support the first base film 4 of which one
surface is provided with the binder resin 2, an array plate 11
which is disposed to face the binder resin 2 of the first base film
4 supported by the support plate 10 and on which a plurality of
through holes 12 arranged in a pattern corresponding to the array
pattern of the electrically conductive particles 3 are formed, and
a spray 13 which is disposed above the array plate 11 and sprays
the charged electrically conductive particles 3 together with a
liquid while applying a voltage to the electrically conductive
particles 3 are used.
[0049] The support plate 10 is one that allows the charged
electrically conductive particles 3 to adsorb to the binder resin 2
that is provided to the first base film 4 as a voltage is applied
between the support plate 10 and the spray 13, and the support
plate 10 is formed of a nickel plate, for example. The material of
the support plate 10 is not limited as long as it exhibits
conductivity.
[0050] The array plate 11 is one that arranges the electrically
conductive particles 3 which have passed through the through holes
12 on the surface of the binder resin 2 in the array pattern of the
through holes 12 as the array plate 11 is disposed close onto the
binder resin 2. On the array plate 11, a plurality of through holes
12 are formed in accordance with a predetermined array pattern of
the electrically conductive particles 3. For example, the array
plate 11 has a plurality of through holes formed in a lattice shape
at equal intervals. By virtue of this, the electrically conductive
particles that have passed through the through holes 12 are equally
disposed on the surface of the binder resin 2 in a lattice pattern.
Incidentally, the through holes 12 can be formed using a known
processing technology such as laser processing.
[0051] The opening size of the through holes 12 is 100% or more of
the average particle size of the electrically conductive particles
3 and preferably from 120 to 200% of the average particle size of
the electrically conductive particles 3. It is difficult for the
electrically conductive particles 3 to pass through the through
holes 12 when the opening size of the through holes 12 is less than
100% of the average particle size of the electrically conductive
particles 3. In addition, when the opening size of the through
holes 12 is 200% or more of the average particle size of the
electrically conductive particles 3, it is concerned that a
plurality of electrically conductive particles 3 pass through one
through hole 12, it is not possible to equally disperse and dispose
the electrically conductive particles, and also it is concerned
that the aggregation of particles is caused.
[0052] The charging of the array plate 11 is prevented so that the
passing of the charged electrically conductive particles 3 via the
through holes 12 will not be impeded by attraction or repulsion.
For example, the array plate 11 is prevented from being charged as
it is grounded as well as formed using an electrically conductive
material such as nickel. Alternatively, the array plate 11 may be
prevented from being charged as it is formed using a hardly charged
material.
[0053] The spray 13 is provided above the array plate 11 and sprays
the electrically conductive particles 3 dispersed in a liquid such
as water together with the liquid via the array plate 11 toward the
binder resin 2 of the first base film 4 that is supported by the
support plate 10. At this time, the spray 13 applies an electrical
charge to have a polarity opposite to the voltage applied to the
support plate 10 to the electrically conductive particles 3. The
spray 13 can charge the electrically conductive particles 3, for
example, by conducting corona discharge at the nozzle tip.
[0054] In order to arrange the electrically conductive particles 3
on the binder resin 2 formed on one surface of the first base film
4 in a predetermined pattern using these support plate 10, array
plate 11, and spray 13, the electrically conductive particles 3
which are charged with an electrical charge are sprayed together
with the liquid from the spray 13 while applying a voltage between
the spray 13 and the support plate 10 to support the first base
film 4 in a state in which the binder resin 2 is turned upward.
[0055] The ejected electrically conductive particles 3 pass through
the through holes 12 of the array plate 11 as well as are uniformly
dispersed by the static electricity, and are attached onto the
surface of the binder resin 2 on the first base film 4 supported by
the support plate 10 to which the opposite polarity is applied in a
pattern corresponding to the array pattern of the through holes 12
(FIG. 4(A)). Incidentally, the moisture attached to the
electrically conductive particles 3 is thrown off from the surface
of the electrically conductive particles 3 during a fall.
[0056] [Film Thickness of Insulating Film 3a]
[0057] Here, the electrically conductive particles 3 are attached
onto the surface of the binder resin 2 by being attracted to the
support plate 10 to which the opposite polarity is applied, and
thus the electrically conductive particles 3 are required to be
charged with an electrical charge at least until being attached
onto the surface of the binder resin 2. Hence, as described above,
as the insulating film 3a to be charged with an electrical charge
is formed so as to have a film thickness of 0.1% or more of the
particle size of the electrically conductive particles 3, the
electrically conductive particles 3 do not lose the electrostatic
property before being attached to the binder resin 2 and are
securely and equally dispersed and disposed in accordance with the
pattern of the through holes 12 of the array plate 11. On the other
hand, the conduction resistance between the connecting terminals
increases when the insulating film 3a of the electrically
conductive particles 3 is too thick. Hence, it is preferable to
form the insulating film 3a in a thickness of from 0.1 to 50% of
the particle size of the electrically conductive particles 3.
[0058] In addition, the respective electrically conductive
particles 3 are charged with an electrical charge having the same
polarity and thus repel one another. This makes it possible to
prevent a plurality of electrically conductive particles 3 from
passing through one through hole 12, and the electrically
conductive particles 3 are arranged on the surface of the binder
resin 2 in a single layer in accordance with the pattern of the
through holes 12.
[0059] After the electrically conductive particles 3 are arranged
in a predetermined pattern corresponding to the pattern of the
through holes 12, the second base film 5 is laminated on the binder
resin 2 on which the electrically conductive particles 3 are
arranged (FIG. 4(B)).
[0060] The second base film 5 pushes the electrically conductive
particles 3 into the binder resin 2 so as to achieve the
positioning of the electrically conductive particles 3. The
electrically conductive particles 3 are held in the binder resin 2
that is coated on the first and second base films 4 and 5 as the
release treated surface of the second base film 5 is bonded to the
surface on which the electrically conductive particles 3 are
transferred of the binder resin 2. By virtue of this, the
anisotropic conductive film 1 is formed in which the binder resin 2
containing the electrically conductive particles 3 is supported by
the first base films 4 and 5 of an upper and lower pair.
[0061] As illustrated in FIG. 4(C), the electrically conductive
particles 3 are pushed into the binder resin 2 as the anisotropic
conductive film 1 is appropriately pressed by a laminating roll 21.
Subsequently, the surface on which the electrically conductive
particles 3 are pushed of the binder resin 2 is cured by being
irradiated with ultraviolet rays from the first base film 4 side,
and the like, and thus the anisotropic conductive film 1 is fixed
in the pattern arranged with the electrically conductive particles
3.
[0062] [Manufacturing Process of Connector]
[0063] The anisotropic conductive film 1 can be suitably used in a
connector in which an IC or a flexible substrate is COG, FOB, or
FOF connected and any devices such as television, or PC, mobile
phones, game machines, audio devices, and tablet terminators, or
vehicle-mounted monitors.
[0064] As illustrated in FIG. 5, a rigid substrate 22 that is
connected to an IC or a flexible substrate via the anisotropic
conductive film 1 is formed of a plurality of connecting terminals
23 arranged in parallel. These connecting terminals 23 are
microminiaturized to meet the requirement of high density mounting
and the interval between the connecting terminals is narrowed.
[0065] At the time of actual use, the anisotropic conductive film 1
is cut such that the size in the width direction corresponds to the
size of the connecting terminal 23, the first base film 4 is then
peeled off therefrom, and the anisotropic conductive film 1 thus
cut is pasted on the plurality of connecting terminals 23 by taking
the parallel direction of the connecting terminals 23 as the
longitudinal direction. Subsequently, the connecting terminal of
the IC or flexible substrate side is mounted on the connecting
terminal 23 via the anisotropic conductive film 1, and the
resultant is heated and pressurized by a pressure tool (not
illustrated) from the top of it.
[0066] By virtue of this, the binder resin 2 is softened, the
electrically conductive particles 3 are pressed and deformed
between the connecting terminals facing each other, and the
anisotropic conductive film 1 is cured in a state in which the
electrically conductive particles 3 are pressed and deformed by
being heated or irradiated with ultraviolet rays. By virtue of
this, the anisotropic conductive film 1 electrically and
mechanically connects an IC or a flexible substrate to a connecting
target such as a glass substrate.
[0067] Here, in the anisotropic conductive film 1, the electrically
conductive particles 3 are equally arranged in a lattice shape
throughout the longitudinal direction. Hence, it is possible to
improve the conduction properties as the anisotropic conductive
film 1 is securely captured on the microminiaturized connecting
terminals 23, and also it is possible to prevent a short circuit
between adjacent terminals as the electrically conductive particles
3 are not linked to one another in the narrowed intervals between
connecting terminals.
[0068] [Content of Aggregate]
[0069] Incidentally, as described above, according to the
invention, the electrically conductive particles 3 ejected from the
spray 13 pass through the through holes 12 of the array plate 11 as
well as are uniformly dispersed by the static electricity, and are
attached onto the surface of the binder resin 2 on the first base
film 4 in a pattern corresponding to the array pattern of the
through holes 12 (FIG. 4(A)).
[0070] At this time, aggregates in which a plurality of
electrically conductive particles 3 are linked to one another is
within 15%, preferably within 8%, more preferably 5% of the total
number of electrically conductive particles. The size of the
aggregate is set to be preferably 8 times or less and more
preferably 5 times or less the average particle size of the
electrically conductive particles at most. The size of the
aggregate mentioned here also includes the maximum length of the
aggregate in which the electrically conductive particles 3 are
linked to one another.
[0071] [Abrasion by Through Hole]
[0072] In addition, a fine abrasion which is believed to be
generated by friction with the through holes 12 is generated on the
electrically conductive particles 3 in some cases. This abrasion is
generated at approximately from 3 to 20% of the surface area of the
electrically conductive particles 3. In addition, there are the
abraded electrically conductive particles 3 at 0.5% or more of the
total number of the electrically conductive particles, and the flow
of the electrically conductive particles 3 is suppressed by this at
the time of transfer to the binder resin 2 or at the time of
thermal pressurization of the anisotropic conductive film 1. In
addition, the conduction performance is not affected when the
abraded electrically conductive particles 3 are within 30% of the
total number of the electrically conductive particles, but it is
preferable that the abraded electrically conductive particles 3 are
within 15% of the total number of the electrically conductive
particles.
Second Embodiment
[0073] Incidentally, the support plate to support the first base
film may be formed in a roll shape as illustrated in FIG. 6 in
addition to a plate shape. The roll-shaped support plate 30 conveys
the first base film 4 by being rotated. In addition, the array
plate 11 is disposed on the upper part of the first base film 4
supported by the roll-shaped support plate 30. Furthermore, a
voltage is applied between the roll-shaped support plate 30 and the
spray 13 facing the array plate 11 such that the roll-shaped
support plate 30 is charged in a polarity opposite to the
electrical charge of the electrically conductive particles that are
ejected from the spray 13.
[0074] Thereafter, the electrically conductive particles 3 ejected
from the spray 13 pass through the through holes 12 of the array
plate 11 and are attached onto the surface of the binder resin 2
provided on the base film 4 in a predetermined pattern when the
first base film 4 moves on the upper part of the roll-shaped
support plate 30. This makes it possible to continuously arrange
the electrically conductive particles 3 on the binder resin 2 of
the first base film 4 that is conveyed by the roll-shaped support
plate 30, and thus it is possible to improve the manufacturing
efficiency.
[0075] Furthermore, the first base film 4 in which the electrically
conductive particles 3 are arranged on the surface of the binder is
continuously subjected to the roll lamination of the second base
film 5 and the light curing of the adhesive layer on the downstream
side in the conveying direction in the same manner, and thus it is
possible to continuously form the anisotropic conductive film 1 by
a series of steps.
EXAMPLES
[0076] Subsequently, Examples of the invention will be described.
In the present Examples, a plurality of the anisotropic conductive
films which were manufactured by different manufacturing methods
and had different configurations of the electrically conductive
particles were prepared, and connector samples were manufactured in
which an IC was connected onto a glass substrate using each of the
anisotropic conductive films. Thereafter, the conduction resistance
(.OMEGA.) and the proportion (ppm) of short circuit between
terminals were determined for each of the connector samples.
[0077] In the anisotropic conductive films according to Examples
and Comparative Examples, a resin composition prepared by
blending:
[0078] 60 parts by mass of a phenoxy resin (YP-50, manufactured by
NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD.); and
[0079] 40 parts by mass of an epoxy resin (jER828, manufactured by
Mitsubishi Chemical Corporation); and
[0080] 2 parts by mass of a cationic curing agent (SI-60L,
manufactured by SANSHIN CHEMICAL INDUSTRY CO., LTD.)
was used as a binder resin.
[0081] As the anisotropic conductive films according to Examples
and Comparative Examples, a mixed solution was prepared by
adjusting the solid content of these resin compositions to be 50%
with toluene, the mixed solution was coated on a PET film having a
thickness of 50 .mu.m, and the coated PET film was dried in an oven
at 80.degree. C. for 5 minutes, thereby obtaining an anisotropic
conductive film containing a binder resin having a thickness of 20
.mu.m.
[0082] In addition, in the anisotropic conductive films according
to Examples and Comparative Examples, AUL704: (resin core Au
plating particles, average particle size: 4 .mu.m, manufactured by
SEKISUI CHEMICAL CO., LTD.) was used as the electrically conductive
particles.
[0083] A glass substrate (trade name: 1737F, manufactured by
Corning Incorporated, size: 50 mm.times.30 mm, thickness: 0.5 mm)
on which an aluminum wiring pattern corresponding to the pattern of
the IC chip was formed was used as the glass substrate.
[0084] The connector sample to be used for the measurement of
conduction resistance (.OMEGA.) was manufactured as follows. The
anisotropic conductive films according to Examples and Comparative
Examples were disposed on this glass substrate, the IC chip
(dimensions: 1.8 mm.times.20.0 mm, thickness: 0.5 mm, gold bump
size: 30 .mu.m.times.85 .mu.m, bump height: 15 .mu.m, pitch: 50
.mu.m) was disposed on the anisotropic conductive film, and the
resultant was heated and pressurized, thereby connecting the IC
chip and the aluminum wiring patterned glass substrate to each
other. The condition for pressure joining was 180.degree. C., 80
MPa, and 5 seconds.
[0085] In addition, the connector sample to be used for the
measurement of proportion (ppm) of short circuit between terminals
was manufactured as follows. The anisotropic conductive films
according to Examples and Comparative Examples were disposed on
this glass substrate, the IC chip (size: 1.5 mm.times.13.0 mm,
thickness: 0.5 mm, gold bump size: 25 .mu.m.times.140 .mu.m, bump
height: 15 .mu.m, pitch: 7.5 .mu.m) was disposed on the anisotropic
conductive film, and the resultant was heated and pressurized,
thereby connecting the IC chip and the aluminum wiring patterned
glass substrate to each other. The condition for pressure joining
was 180.degree. C., 80 MPa, and 5 seconds.
Example 1
[0086] In the manufacturing process of the anisotropic conductive
film according to Example 1, the electrically conductive particles
were arranged on the binder resin formed on one surface of a PET
film in a predetermined pattern and then pushed into the binder
resin by laminating a release-treated PET film on the surface on
which the electrically conductive particles were arranged of the
binder resin, thereby manufacturing the anisotropic conductive
film.
[0087] For the arrangement of the electrically conductive
particles, an electrically conductive support plate to support a
PET film provided with a binder resin, an array plate which was
disposed to face the binder resin of the PET film supported by the
support plate and on which a plurality of through holes arranged in
a pattern corresponding to the array pattern of the electrically
conductive particles were formed, and a spray which was disposed
above the array plate and sprayed the charged electrically
conductive particles together with a liquid while applying a
voltage to the electrically conductive particles were used (see
FIG. 3).
[0088] Thereafter, the electrically conductive particles which were
charged with an electrical charge were sprayed together with water
from the spray while applying a voltage between the spray and the
support plate. The ejected electrically conductive particles passed
through the through holes of the array plate as well as were
uniformly dispersed by the static electricity, and were attached
onto the surface of the binder resin on the PET film supported by
the support plate to which the opposite polarity was applied in a
pattern corresponding to the array pattern of the through
holes.
[0089] Thereafter, the electrically conductive particles 3 were
pushed into the binder resin by laminating a release-treated PET
film on the surface of the binder resin using a laminating roll,
thereby obtaining the anisotropic conductive film.
[0090] This anisotropic conductive film was pasted on a plurality
of connecting terminals by taking the parallel direction of the
connecting terminals of an aluminum wiring pattern formed on a
glass substrate as the longitudinal direction.
[0091] Here, in Example 1, the insulating film (polymethyl
methacrylate) was formed on the surface of the electrically
conductive particles in a thickness of 0.1% of the average particle
size (4 .mu.m) of the electrically conductive particles.
Example 2
[0092] In Example 2, the conditions were the same as those in
Example 1 except that the thickness of the insulating film formed
on the surface of the electrically conductive particles was 10% of
the average particle size (4 .mu.m) of the electrically conductive
particles.
Example 3
[0093] In Example 3, the conditions were the same as those in
Example 1 except that the thickness of the insulating film formed
on the surface of the electrically conductive particles was 50% of
the average particle size (4 .mu.m) of the electrically conductive
particles.
Comparative Example 1
[0094] In Comparative Example 1, an anisotropic conductive film was
obtained by a manufacturing method of prior art. In other words, an
anisotropic conductive film molded in a film shape was obtained by
coating a resin composition prepared by dispersing electrically
conductive particles (AUL704) in the binder resin described above
on a PET film and drying it. In the anisotropic conductive film
according to Comparative Example 1, the electrically conductive
particles are randomly disposed in the binder resin.
[0095] Incidentally, in Comparative Example 1, the thickness of the
insulating film formed on the surface of the electrically
conductive particles was 10% of the average particle size (4 .mu.m)
of the electrically conductive particles.
[0096] This anisotropic conductive film was pasted on a plurality
of connecting terminals by taking the parallel direction of the
connecting terminals of an aluminum wiring pattern formed on a
glass substrate as the longitudinal direction.
Comparative Example 2
[0097] In Comparative Example 2, a pressure sensitive adhesive
layer was formed by coating an acrylic polymer on a 100 .mu.m of
unstretched copolymerized polypropylene film and drying it. The
electrically conductive particles (AUL704) were filled all over
this pressure sensitive adhesive material layer, and the
electrically conductive particles that did not reach the pressure
sensitive adhesive were removed by air blowing, thereby forming a
single-layer electrically conductive particle layer having a
filling rate of 60%.
[0098] Next, this polypropylene film on which the electrically
conductive particles were fixed was stretched to 2.0 times at
135.degree. C. and at a ratio of 10%/sec in both vertical and
horizontal directions using a biaxial stretching apparatus for test
and was gradually cooled up to room temperature, thereby obtaining
an array sheet.
[0099] Next, a PET film coated with a binder resin (transfer film)
was superimposed on the electrically conductive particle side of
this array sheet and laminated under the condition of 60.degree. C.
and 0.3 MPa to embed the electrically conductive particles into the
binder resin, and the polypropylene film and the pressure sensitive
adhesive were peeled off therefrom. Thereafter, a second PET film
was bonded on the PET film in the same manner as in Example 1,
thereby obtaining an anisotropic conductive film.
[0100] This anisotropic conductive film was pasted on a plurality
of connecting terminals by taking the parallel direction of the
connecting terminals of an aluminum wiring pattern formed on a
glass substrate as the longitudinal direction.
[0101] Incidentally, in Comparative Example 2, the thickness of the
insulating film formed on the surface of the electrically
conductive particles was 10% of the average particle size (4 .mu.m)
of the electrically conductive particles.
Comparative Example 3
[0102] In Comparative Example 3, the conditions were the same as
those in Example 1 except that the thickness of the insulating film
formed on the surface of the electrically conductive particles was
0.05% of the average particle size (4 .mu.m) of the electrically
conductive particles.
Comparative Example 4
[0103] In Comparative Example 4, the conditions were the same as
those in Example 1 except that the thickness of the insulating film
formed on the surface of the electrically conductive particles was
80% of the average particle size (4 .mu.m) of the electrically
conductive particles.
[0104] Connector samples were manufactured in which an IC was
connected onto a glass substrate using these anisotropic conductive
films according to the respective Examples and Comparative
Examples. Thereafter, the conduction resistance (.OMEGA.) and the
proportion (ppm) of short circuit between terminals were determined
for each of the respective connector samples. The results are
presented in Table 1.
TABLE-US-00001 TABLE 1 Comparative Comparative Comparative
Comparative Example 1 Example 2 Example 3 Example 1 Example 2
Example 3 Example 4 Arrangement of Equal Equal Equal Random Equal
Equal Equal electrically conductive disposition disposition
disposition disposition disposition disposition disposition
particles Thickness of insulating 0.10 10 50 10 10 0.05 80 film
with respect to size of electrically conductive particles (%)
Conduction 0.2 0.2 0.5 0.2 0.2 0.2 2.0 resistance (.OMEGA.)
Proportion of short 1 or less 1 or less 1 or less 3000 300 130 1 or
less circuit between terminals (ppm)
[0105] As presented in Table 1, in all of Examples 1 to 3, the
conduction resistance between the IC chip and the connecting
terminal formed on the glass substrate was as low as 0.5.OMEGA. or
less and the proportion of short circuit between the terminals was
also 1 ppm or less.
[0106] On the other hand, in Comparative Example 1, although the
conduction resistance was as low as 0.2.OMEGA., the proportion of
short circuit between the terminals was as frequent as 3000 ppm. In
the same manner, in Comparative Example 2, although the conduction
resistance was as low as 0.2.OMEGA., the proportion of short
circuit between the terminals was as frequent as 3000 ppm, and in
Comparative Example 3 as well, although the conduction resistance
was as low as 0.2.OMEGA., the proportion of short circuit between
the terminals was as frequent as 130 ppm. In addition, in
Comparative Example 4, although the proportion of short circuit
between the terminals was as rare as 1 ppm or less, the conduction
resistance was as high as 2.0.OMEGA..
[0107] This is because, in Examples 1 to 3, the anisotropic
conductive films manufactured using the manufacturing process
according to the invention were used, and thus the electrically
conductive particles were equally dispersed and disposed in a
pattern corresponding to the pattern of the through holes 12 of the
array plate 11, a high particle capture rate was maintained even
though the connecting terminal was microminiaturized and the
interval between the connecting terminals was narrowed, and also it
was possible to prevent a short circuit between terminals having a
narrowed interval as the aggregation of particles was
prevented.
[0108] On the other hand, in Comparative Example 1, the
electrically conductive particles were randomly dispersed in the
binder resin, and thus the locations at which the electrically
conductive particles were concentrated and the locations at which
the electrically conductive particles were dispersed were generated
in the binder resin, the electrically conductive particles were
linked to one another between the adjacent terminals having a
narrowed interval, and thus a short circuit between terminals
occurred as frequently as 3000 ppm.
[0109] In addition, in Comparative Example 2, not all of the
electrically conductive particles were separated from one another
by the method to separate the electrically conductive particles
from one another by biaxial stretching, the aggregate of particles
in which a plurality of electrically conductive particles were
linked to one another remained, and the short circuit between the
adjacent terminals having a narrowed interval occurred as
frequently as 300 ppm, and thus it was not possible to completely
prevent the short circuit.
[0110] In addition, in Comparative Example 3, the film thickness of
the insulating film formed on the surface of the electrically
conductive particles was less than 0.1% of the average particle
size of the electrically conductive particles, thus the
electrically conductive particles lost the electrostatic property
after being ejected from the spray but before being attached onto
the surface of the binder resin, and because of this, the
electrically conductive particles were randomly scattered, and also
the electrically conductive particles were not equally dispersed
and disposed as a plurality of electrically conductive particles
passed through one through hole. For this reason, in Comparative
Example 3 as well, the aggregation of particles in which a
plurality of electrically conductive particles were linked to one
another occurred, thus a short circuit between adjacent terminals
having a narrowed interval occurred as frequently as 130 ppm and it
was not possible to completely prevent the short circuit.
[0111] In addition, in Comparative Example 4, the film thickness of
the insulating film formed on the surface of the electrically
conductive particles was thick to be 80% of the average particle
size of the electrically conductive particles, and the thick
insulating film inhibited the conduction properties when the
anisotropic conductive film was sandwiched between the connecting
terminals. For this reason, in Comparative Example 4, although the
electrostatic property was favorable and the proportion of short
circuit between the adjacent terminals was 1 ppm to be favorable,
but the conduction resistance was as high as 2.0.OMEGA..
[0112] From this, it can be seen that it is preferable that the
thickness of the insulating film formed on the surface of the
electrically conductive particles is 0.1% or more and 50% or less
of the particle size of the electrically conductive particles.
REFERENCE SIGNS LIST
[0113] 1 Anisotropic conductive film, 2 Binder resin, 3
Electrically conductive particles, 3a Insulating film, 4 First base
film, 5 Second base film, 6 Take-up reel, 10 Support plate, 11
Array plate, 12 Through hole, 13 Spray, 21 Laminating roll, 22
rigid substrate, 23 Connecting terminal
* * * * *