JP3257433B2 - Method for producing anisotropic conductive sheet and anisotropic conductive sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an anisotropically conductive sheet which is preferably used as a connector in an electrical connection between circuit elements such as electronic parts and a printed circuit board inspection apparatus, and an anisotropically conductive sheet. <br>.

[0002]

2. Description of the Related Art An anisotropic conductive elastomer sheet has conductivity only in the thickness direction, or has a pressurized conductive portion which has conductivity only in the thickness direction when pressed in the thickness direction. And it is possible to achieve a compact electrical connection without using means such as soldering or mechanical fitting, and it is possible to absorb mechanical shocks and strains and make a soft connection Because of these features, using such features, for example, computers,
In the fields of electronic digital watches, electronic cameras, computer keyboards, etc., it is widely used as a connector for achieving an electrical connection between circuit elements, for example, a printed circuit board and a leadless chip carrier, a liquid crystal panel, etc. ing.

In electrical inspection of a circuit board such as a printed board, an electrode to be inspected formed on one surface of a circuit board to be inspected and a connection electrode formed on the surface of the inspection circuit board are electrically connected. In order to achieve electrical connection, an anisotropic conductive elastomer sheet is interposed between an electrode area to be inspected on a circuit board and a connection electrode area on a circuit board for inspection.

Conventionally, as such an anisotropic conductive elastomer sheet, those having various structures are known. For example, Japanese Patent Application Laid-Open No. Sho 51-93393 discloses that metal particles are uniformly dispersed in an elastomer. Anisotropic conductive elastomer sheet (hereinafter referred to as “dispersion type anisotropic conductive elastomer sheet”) obtained by the method described in JP-A-53-147772 is disclosed. By distributing the particles non-uniformly in the elastomer, an anisotropic conductive elastomer sheet (hereinafter, referred to as an electrically conductive elastomer sheet) in which a number of conductive path forming portions extending in the thickness direction and insulating portions that insulate them from each other are formed. "Eccentrically distributed anisotropic conductive elastomer sheet") is disclosed.
Japanese Unexamined Patent Publication No. 250906/2005 discloses an unevenly distributed anisotropic conductive elastomer sheet in which a step is formed between the surface of a conductive path forming portion and an insulating portion.

[0005] The unevenly distributed anisotropic conductive elastomer sheet has a conductive path forming portion formed in accordance with a pattern opposite to an electrode pattern of a circuit board or the like. This is advantageous in that electrical connection between the electrodes can be achieved with high reliability even on a circuit board or the like on which electrodes to be connected are arranged at a small pitch.

[0006] However, it has been found that the conventional unevenly distributed anisotropic conductive elastomer sheet has the following problems. Conventionally, an unevenly distributed anisotropic conductive elastomer sheet is manufactured, for example, as follows. As shown in FIG. 14, for example, a ferromagnetic material portion 81 is arranged according to the same pattern as an electrode to be inspected on a circuit board to be inspected, and a non-magnetic material portion 82 is provided in a portion other than the ferromagnetic material portion 81. The ferromagnetic portion 86 is arranged in accordance with a pattern 80 (hereinafter, referred to as an “upper mold”) and a pattern opposite to an electrode to be inspected of a circuit board to be inspected. The other mold (hereinafter referred to as “lower mold”) 85 in which the non-magnetic material part 87 is disposed in a part other than the body part 86, is cured between the upper mold 80 and the lower mold 85. An anisotropic conductive elastomer-forming material layer 90A is formed by dispersing conductive magnetic particles in a polymer-forming material to be an elastic polymer material.

Next, as shown in FIG. 15, a pair of electromagnets 83 and 88 are arranged on the upper surface of the upper die 80 and the lower surface of the lower die 85, and the electromagnets 83 and 88 are actuated. A parallel magnetic field is applied in a direction from the magnetic part 81 to the corresponding ferromagnetic part 86 of the lower die 85. As a result, in the anisotropic conductive elastomer-forming material layer 90A, the conductive magnetic particles dispersed in the anisotropic conductive elastomer-forming material layer 90A are:
It gathers at a portion located between the ferromagnetic portion 81 of the upper die 80 and the ferromagnetic portion 86 of the lower die 85, and is oriented so as to be aligned in the thickness direction. Then, in this state, the anisotropic conductive elastomer forming material layer 90A is subjected to, for example, a curing treatment by heating to form a plurality of conductive path forming portions 91 extending in the thickness direction, as shown in FIG. The unevenly distributed anisotropic conductive elastomer sheet 90 having the insulating portions 92 insulated from each other is manufactured.

Therefore, a very small pitch, for example, 100
When manufacturing an unevenly distributed anisotropic conductive elastomer sheet having a thickness of, for example, 300 μm corresponding to a circuit board to be inspected on which electrodes to be inspected are arranged at a pitch of μm or less, the ferromagnetic portions 81, It is necessary to use the upper die 80 and the lower die 85 in which the 86s are arranged at an extremely small pitch. However, such an upper die 80 and a lower die 8
In the case of manufacturing an unevenly distributed anisotropic conductive elastomer sheet having a thickness of, for example, 300 μm as described above, using each of the upper mold 80 and the lower mold 85 as shown in FIG. Since the distance between the magnetic portions 81a and 86a and the ferromagnetic portions 81b and 86b adjacent thereto is small and the distance between the upper die 80 and the lower die 85 is large, the ferromagnetic portion 81a of the upper die 80 is large. From the ferromagnetic material portion 86a of the lower die 85 to the corresponding ferromagnetic material portion 86a of the lower die 85 (indicated by an arrow X). 86
a toward the ferromagnetic portion 86b adjacent to the
(Shown by). Therefore, in the anisotropic conductive elastomer-forming material layer 90A, the conductive magnetic particles are transferred between the ferromagnetic portion 81a of the upper die 80 and the corresponding ferromagnetic portion 86a of the lower die 85. And the conductive magnetic particles also aggregate in a portion located between the ferromagnetic portion 81a of the upper die 80 and the ferromagnetic portion 86b of the lower die 85. As a result, The desired unevenly distributed anisotropic conductive elastomer sheet cannot be obtained.

Further, the conventional anisotropic conductive elastomer sheet has the following problems. As the elastic polymer material constituting the anisotropic conductive elastomer sheet,
Generally, silicone rubber is used, and among these silicone rubbers, those having a low molecular weight (oil-like) are used.
Is contained. When such an anisotropically conductive elastomer sheet is used for a long time, for example, for inspecting a circuit board, low-molecular-weight silicone bleeds out on the surface of the anisotropically conductive elastomer sheet. And the surface of the electrode to be inspected is contaminated. As a result, when mounting the circuit board, there arises a problem that bonding cannot be performed or electrical connection cannot be achieved.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to arrange electrodes to be connected at a very small pitch and to increase the thickness of the sheet. And a method for advantageously producing an anisotropically conductive sheet capable of reliably achieving a required electrical connection even when such a sheet is provided.
An object of the present invention is to provide an anisotropic conductive sheet by the method.

[0011]

According to the method of manufacturing an anisotropic conductive sheet of the present invention , an insulating resin layer is provided on one surface of an insulating sheet body.
And a laminated body in which thin metal layers are laminated in this order.
When penetrating the insulating sheet and the insulating resin layer,
By forming holes that do not penetrate the thin metal layer
Insulating sheet body with a number of through holes
An insulating resin layer provided to cover one surface of the sheet body,
It consists of a thin metal layer provided on the surface of this insulating resin layer.
First step of producing a composite, and insulating properties of the composite
On the other side of the sheet, a high
Flow of conductive particles dispersed in molecular substance forming material
By applying a conductive path element material, the composite
Each of the through holes is filled with a conductive path element material,
To form a conductive path element material layer in each of the through holes.
The second step and a magnetic field parallel to the thickness direction of the conductive path element material layer
To make the conductive particles have a thickness of the conductive layer element material layer.
And harden the conductive layer material layer
Process to form conductive path elements in through holes
The third step is performed.

In the above, the second step is performed in a reduced pressure atmosphere.
Under air, through the insulating sheet on one side
With each opening of the hole sealed by a thin metal layer,
Apply conductive path element material to the other surface of the insulating sheet
Then, by raising the atmospheric pressure,
Each of the through holes of the edge sheet is filled in the through hole.
By forming the conductive layer element material layer in the
May be.

After the third step, the conductive path element in the thin metal layer
Removal of parts other than where the child is located is performed
Is also good.

[0014] The anisotropic conductive sheet of the present invention is manufactured by the method described above.
It is characterized by being manufactured by the method.

[0015]

Embodiments of the present invention will be described below in detail. FIG. 1 is an explanatory cross-sectional view showing a configuration of a main part in an example of the anisotropic conductive sheet according to the present invention . In the anisotropic conductive sheet 10, a large number of through holes 2 penetrating and extending in the thickness direction according to a specific pattern.
An insulating sheet body 20 on which the sheet 1 is formed is provided.
The specific pattern in the through-hole 21 of the insulating sheet body 20 is a pattern corresponding to the pattern of the electrode to be connected. In each of the through holes 21 of the insulating sheet body 20, a conductive path element 30 is provided integrally with the insulating sheet body 20 in a state where the conductive path element 30 is filled in the through hole 21. Are substantially independent of each other. The conductive path element 30 in the illustrated example includes:
The upper surface is formed so as to slightly protrude from the upper surface of the insulating sheet body 20.

Further, in the anisotropic conductive sheet 10 of this embodiment, an insulating resin layer 25 is provided so as to cover the upper surface of the insulating sheet body 20, and a metal is formed so as to cover the upper surface of the conductive path element 30. A layer 35 is provided. The thickness of the insulating resin layer 25 is equal to the height of the conductive path element 30 projecting from the upper surface of the insulating sheet body 20.

The insulating sheet 20 is made of an elastic high-molecular substance having an insulating property. Curable polymer material forming materials that can be used to obtain such an elastic polymer material include polybutadiene rubber, natural rubber,
Conjugated diene rubbers such as polyisoprene rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber and hydrogenated products thereof, styrene-butadiene-diene block copolymer rubber, styrene-isoprene block copolymer Block copolymer rubbers and hydrogenated products thereof, chloroprene, urethane rubber, polyester rubber, epichlorohydrin rubber, silicone rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, and the like. When weather resistance is required for the resulting anisotropic conductive sheet, it is preferable to use a material other than the conjugated diene rubber.

As shown in FIG. 2, the conductive path element 30 is formed by containing conductive particles P in an elastic polymer material E, and preferably, the conductive particles P are contained in the elastic polymer material E in the thickness direction. The conductive particles P form a conductive path in the thickness direction of the conductive path element 30. The conductive path element 30 may be a pressurized conductive path element in which a conductive path is formed by reducing the resistance value when compressed and compressed in the thickness direction. Further, the conductive path of the conductive path element 30 may be formed over the entire area thereof in a cross section perpendicular to the thickness direction of the conductive path element 30, or may be formed only in a part of the area, for example, only the central area.

The conductive path element 30 is formed by subjecting a fluid conductive path element material obtained by dispersing conductive particles in a polymer material forming material to be cured into an elastic polymer substance to a hardening treatment. You. Various materials can be used as the polymer substance forming material used for the conductive path element material. Specific examples thereof include polybutadiene rubber, natural rubber, polyisoprene rubber, styrene-butadiene copolymer rubber, and acrylonitrile. -Conjugated diene rubbers such as butadiene copolymer rubber and hydrogenated products thereof, styrene-butadiene-diene block copolymer rubber, block copolymer rubbers such as styrene-isoprene block copolymer and hydrogenated products thereof , Chloroprene,
Examples include urethane rubber, polyester rubber, epichlorohydrin rubber, silicone rubber, ethylene-propylene copolymer rubber, and ethylene-propylene-diene copolymer rubber. In the above, when weather resistance is required for the obtained anisotropic conductive sheet, it is preferable to use a material other than the conjugated diene rubber, and particularly, from the viewpoint of moldability and electrical characteristics, use of silicone rubber Is preferred.

The silicone rubber is preferably one obtained by crosslinking or condensing a liquid silicone rubber. The liquid silicone rubber preferably has a viscosity of 10 ⁵ poise or less at a strain rate of 10 ⁻¹ sec, and may be any of condensation type, addition type, and those containing a vinyl group or a hydroxyl group. Good. Specifically, dimethylsilicone raw rubber, methylvinylsilicone raw rubber, methylphenylvinylsilicone raw rubber and the like can be mentioned.

Among them, liquid group-containing silicone rubber (vinyl group-containing polydimethylsiloxane)
Is usually obtained by subjecting dimethyldichlorosilane or dimethyldialkoxysilane to hydrolysis and condensation reaction in the presence of dimethylvinylchlorosilane or dimethylvinylalkoxysilane, for example, followed by fractionation by repeated dissolution-precipitation. Also,
The liquid silicone rubber containing vinyl groups at both ends is anionically polymerized with a cyclic siloxane such as octamethylcyclotetrasiloxane in the presence of a catalyst, and uses, for example, dimethyldivinylsiloxane as a polymerization terminator and other reaction conditions (for example, , The amount of the cyclic siloxane and the amount of the polymerization terminator). Here, as a catalyst for anionic polymerization, alkali such as tetramethylammonium hydroxide and n-butylphosphonium hydroxide or a silanolate solution thereof can be used. The reaction temperature is, for example, 80 to 130 ° C. Such a vinyl group-containing polydimethylsiloxane preferably has a molecular weight Mw (weight average molecular weight in terms of standard polystyrene; the same applies hereinafter) of 10,000 to 40,000. In addition, from the viewpoint of heat resistance of the obtained conductive path element, the molecular weight distribution index (the value of the ratio Mw / Mn between the standard polystyrene-equivalent weight average molecular weight Mw and the standard polystyrene-equivalent number average molecular weight Mn; the same applies hereinafter) is 2. 0.0 or less is preferable.

On the other hand, a liquid silicone rubber containing hydroxyl groups (hydroxyl group-containing polydimethylsiloxane) is usually prepared by hydrolyzing dimethyldichlorosilane or dimethyldialkoxysilane in the presence of dimethylhydrochlorosilane or dimethylhydroalkoxysilane. And condensation reaction, for example,
It is obtained by performing fractionation by repeating precipitation.
Further, cyclic siloxane is anionically polymerized in the presence of a catalyst, and dimethylhydrochlorosilane, methyldihydrochlorosilane or dimethylhydroalkoxysilane is used as a polymerization terminator, and other reaction conditions (for example, the amount of the cyclic siloxane and the polymerization termination) are used. Amount of agent)
Can also be obtained by appropriately selecting Here, as a catalyst for anionic polymerization, alkali such as tetramethylammonium hydroxide and n-butylphosphonium hydroxide or a silanolate solution thereof can be used. The reaction temperature is, for example, 80 to 130 ° C. Such hydroxyl group-containing polydimethylsiloxane is,
It is preferable that the molecular weight Mw is 10,000 to 40,000. Further, from the viewpoint of heat resistance of the obtained conductive path element, those having a molecular weight distribution index of 2.0 or less are preferable. In the present invention, either one of the above-mentioned vinyl group-containing polydimethylsiloxane and hydroxyl group-containing polydimethylsiloxane can be used, or both can be used in combination.

The material for the conductive path element may contain a curing catalyst for curing the above-mentioned polymer material forming material. As such a curing catalyst, an organic peroxide, a fatty acid azo compound, a hydrosilylation catalyst, or the like can be used. Specific examples of the organic peroxide used as the curing catalyst include benzoyl peroxide, bisdicyclobenzoyl peroxide, dicumyl peroxide, and ditertiary butyl peroxide. Specific examples of the fatty acid azo compound used as a curing catalyst include azobisisobutyronitrile. Specific examples of those that can be used as a catalyst for the hydrosilylation reaction include:
Chloroplatinic acid and its salts, siloxane complex containing platinum-unsaturated group, complex of vinylsiloxane and platinum, complex of platinum and 1,3-divinyltetramethyldisiloxane, complex of triorganophosphine or phosphite and platinum And acetylacetate platinum chelate, and a complex of a cyclic diene and platinum. The amount of the curing catalyst to be used is appropriately selected in consideration of the type of the polymer substance forming material, the type of the curing catalyst, and other curing treatment conditions.
１５15 parts by weight.

As the conductive particles used for the material for the conductive path element, it is preferable to use conductive magnetic particles from the viewpoint that the particles can be easily oriented by a method described later. Specific examples of the conductive magnetic particles include particles of a metal exhibiting magnetism such as iron and cobalt, particles of an alloy thereof, or particles containing these metals, or particles containing these metals as core particles. The surface of gold, silver, palladium, plated with a metal with good conductivity such as rhodium, or inorganic particles or polymer particles such as non-magnetic metal particles or glass beads as core particles, the core particles Nickel on the surface,
Examples thereof include those obtained by plating a conductive magnetic material such as cobalt, and those obtained by coating core particles with both a conductive magnetic material and a metal having good conductivity. Among them, it is preferable to use nickel particles as core particles, and to use a surface thereof plated with a metal having good conductivity such as gold or silver, and particularly, both gold and silver are coated. Are preferred. Means for coating the surface of the core particles with a conductive metal is not particularly limited, but may be, for example, chemical plating or electroless plating.

When the conductive particles are formed by coating the surface of a core particle with a conductive metal, from the viewpoint of obtaining good conductivity, the coverage of the conductive metal on the particle surface (core particle) Is preferably 40% or more, more preferably 45% or more, and particularly preferably 47 to 95%. Moreover, the coating amount of the conductive metal is 2.5 to
It is preferably 50% by weight, more preferably 3 to
It is 30% by weight, more preferably 3.5 to 25% by weight, particularly preferably 4 to 20% by weight. When the conductive metal to be coated is gold, the coating amount is 3 to
It is preferably 30% by weight, more preferably 3.
It is from 5 to 15% by weight, more preferably from 3 to 20% by weight, particularly preferably from 4.5 to 10% by weight. When the conductive metal to be coated is silver, the coating amount is preferably 3 to 30% by weight of the core particles, more preferably 4 to 25% by weight, and further preferably 5 to 23% by weight. %, Particularly preferably from 6 to 20% by weight. Furthermore, when both gold and silver are used as the conductive metal to be coated, the coating amount of gold is preferably 0.1 to 5% by weight of the core particles, more preferably 0.2 to 4% by weight. % By weight, more preferably 0.5 to 3% by weight.
It is preferably 3 to 30% by weight of the core particles, more preferably 4 to 25% by weight, and still more preferably 5 to 20% by weight.

The conductive particles have a particle size of 1 to 100.
0 μm, more preferably 2 to 50 μm.
0 μm, more preferably 5 to 300 μm, particularly preferably 10 to 200 μm. Further, the particle size distribution (Dw / Dn) of the conductive particles is preferably 1 to 10, more preferably 1.01 to 7, further preferably 1.05 to 5, and particularly preferably 1.1 to 1. 4. By using conductive particles that satisfy such conditions,
The resulting conductive path element 30 can be easily deformed under pressure, and sufficient electrical contact between the conductive particles can be obtained in the conductive path element 30. In addition, the shape of the conductive particles is not particularly limited, but in terms of being easily dispersible in the polymer material, a spherical shape,
It is preferable that the particles have a star shape or a lump formed by agglomerated secondary particles.

The water content of the conductive particles is preferably at most 5%, more preferably at most 3%, further preferably at most 2%, particularly preferably at most 1%. By using the conductive particles satisfying such conditions, it is possible to prevent bubbles from being generated in the conductive path element material layer when the conductive path element material layer is cured in the manufacturing method described below or Is suppressed.

Further, a conductive particle whose surface has been treated with a coupling agent such as a silane coupling agent can be used as appropriate. When the surface of the conductive particles is treated with the coupling agent, the adhesiveness between the conductive particles and the elastic polymer material is increased, and as a result, the obtained conductive path element 30 has durability in repeated use. Will be higher. The amount of the coupling agent used is appropriately selected within a range that does not affect the conductivity of the conductive particles. However, the coverage of the coupling agent on the surface of the conductive particles (the ratio of the coupling agent to the surface area of the conductive core particles). (The ratio of the coverage area) is preferably 5% or more, more preferably 7 to 100%, more preferably 10 to 10%.
The amount is 100%, particularly preferably 20 to 100%.

Such conductive particles are used in a volume fraction of 30 to 60%, preferably 35 to 60%, based on the polymer material.
It is preferable to use it at a ratio of 50%. When this ratio is less than 30%, a conductive path element having a sufficiently small electric resistance value may not be obtained. On the other hand, when this ratio exceeds 60%, the obtained conductive path element tends to be fragile, and the elasticity required for the conductive path element may not be obtained.

In the material for the conductive path element, if necessary,
Inorganic fillers such as ordinary silica powder, colloidal silica, airgel silica, and nalmina can be contained. By including such an inorganic filler, the thixotropic property of the conductive path element material is secured, the viscosity is increased, and the dispersion stability of the conductive particles is improved, and the conductive particles are cured. The strength of the conductive path element to be obtained is increased. The use amount of such an inorganic filler is not particularly limited, but when used in an excessively large amount, in the production method described later, it becomes impossible to sufficiently achieve the orientation of the conductive particles by a magnetic field, Not preferred. Further, the viscosity of the conductive path element material is 25 ° C.
It is preferable that the temperature is in the range of 100,000 to 1,000,000 cp at a temperature of ° C. Then, the above-described material for the conductive path element is subjected to a hardening treatment, whereby the conductive path element 30 is formed.
Is formed.

As the resin material constituting the insulating resin layer 25, polyimide resin, polyamide resin, polyester resin, PET (polyethylene terephthalate) resin, P
TFE (polytetrafluoroethylene) resin or the like can be used. The thickness of the insulating resin layer 25 is, for example, 0.01 to 0.2 mm, and preferably 0.02 to 0.15 mm.

As a metal material constituting the metal layer 35,
Copper, gold, rhodium, platinum, palladium, nickel, their plating, or alloys thereof can be used. The thickness of the metal layer 35 is, for example, 0.001 to 0.2 mm, preferably 0.01 to 0.2 mm.
0.15 mm.

Such an anisotropic conductive sheet 10 is used for inspection of a circuit board as follows, for example. In the inspection of the circuit board, as shown in FIG. 3, a connection electrode 4 arranged on the surface according to a pattern opposite to the electrode 2 to be inspected of the circuit board 1 to be inspected is provided on the surface. , For example, the pitch is 2.54 mm, 1.80 m
An inspection circuit board 3 having terminal electrodes 5 arranged on the back surface according to a lattice point arrangement of m or 1.27 mm is used. Then, an anisotropic conductive sheet 10 is arranged on the surface of the inspection circuit board 3 such that the other end of the conductive path element on the other surface side is located on the connection electrode 4. On the sheet 10, the circuit board 1 to be inspected and the electrodes 2 to be inspected are the metal layers 35 of the anisotropic conductive sheet 10.
It is arranged so as to be located on the top.

Then, for example, by moving the circuit board 3 for inspection in a direction approaching the circuit board 1 to be inspected, the anisotropic conductive sheet 10 is pressed by the circuit board 1 for inspection and the circuit board 3 for inspection. With this pressing force, a conductive path extending in the thickness direction of the conductive path element 30 of the anisotropic conductive sheet 10 is formed. As a result, the test target electrode 2 of the test target circuit board 1 and the test circuit board An electrical connection between the connection electrode 3 and the connection electrode 4 is achieved, and a required inspection is performed in this state.

According to the anisotropic conductive sheet 10 having the above-described structure, a large number of through holes 21 formed in the insulating sheet body 20 are provided.
Since the conductive path element 30 is provided integrally with the conductive sheet element 30, the arrangement pattern of the conductive path element 30 is determined according to the pattern of the through holes 21 of the insulating sheet member 20. The formation of the through holes 21 in the insulating sheet body 20 can be easily performed even if the pitch is extremely small. Therefore, even when the arrangement pitch of the electrodes 2 to be inspected on the substrate 1 to be inspected is extremely small, the through holes 21 of the pattern corresponding to the arrangement pattern of the electrodes 2 to be inspected of the substrate 1 to be inspected are formed in the insulating sheet 20.
Is formed, the conductive path elements 30 are arranged according to the pattern corresponding to the arrangement pattern of the electrodes 2 to be inspected on the substrate 1 to be inspected, and each of the conductive path elements 30
Since they are provided in a state of being insulated from each other by the insulating sheet member 20, the required electrical connection can be reliably achieved even with respect to the test substrate 1 having the test electrodes 2 whose arrangement pitch is extremely small. it can.

The insulating sheet body 20 is provided with an insulating resin layer 25 so as to cover one surface in contact with the substrate 1 to be inspected. Metal layer 3 covering one end face contacting test electrode 2
5, the insulating sheet 20 and the conductive path element 30 are provided on the surfaces of the substrate 1 and the electrode 2 to be inspected.
Are not in contact with each other.
In addition, the surface of the substrate 1 and the electrode 2 is not contaminated by the low molecular weight component contained in the elastic polymer material constituting the conductive path element 30.

Next, a method for producing the anisotropic conductive sheet of the present invention will be described. In the production method of the present invention,
(1) a first step of forming an insulating sheet body made of an elastic polymer material, in which a large number of through holes extending in the thickness direction are formed, and (2) one surface of the insulating sheet body which has been cured. By applying a fluid conductive path element material in which conductive particles are dispersed in a polymer substance forming material to be an elastic polymer substance, each of the through holes of the insulating sheet body has a through hole. A second step of forming a conductive path element material layer in a state of being filled in the insulating sheet body, and (3) performing a curing treatment of the conductive path element material layer to fill the through holes of the insulating sheet body. The anisotropic conductive sheet as described above can be manufactured by the third step of forming the conductive path element in which the conductive particles are contained in the elastic polymer material provided integrally in the state. . Hereinafter, a case where the anisotropic conductive sheet 10 having the configuration shown in FIG. 1 is manufactured will be described.

[First Step] This first step is described in FIGS.
As shown in FIG. 5, an insulating sheet body 20 made of an elastic polymer material and having a plurality of through holes 21 extending in the thickness direction, and an insulating resin provided to cover one surface of the insulating sheet body 20. Layer 25 and the insulating resin layer 25
Metal layer 3 which is a metal layer forming material layer provided on the surface of
This is a step of producing a composite 40 composed of 5A. Specifically, as shown in FIG. 4, an insulating resin film 25A having a thin metal layer 35 on one surface is prepared, and the other surface of the insulating resin film 25A on which the thin metal layer 35 is not formed is illustrated. As shown in FIG. 5, by integrally providing the insulating sheet body 20 made of an elastic polymer material, the insulating resin layer 25 and the thin metal layer 35A are laminated on one surface of the insulating sheet body 20 in this order. A laminated body 40A is obtained.

Then, by forming a hole in the laminate 40A, as shown in FIG. 6, a hole penetrating the insulating sheet body 20 and the insulating resin layer 25 and not penetrating the thin metal layer 35A is formed. 41, thereby forming an insulating sheet body 20 having a large number of through holes 21, an insulating resin layer 25 provided to cover one surface of the insulating sheet body 20, and an insulating resin layer Thus, a composite 40 including the thin metal layer 35A provided on the surface of the substrate 25 is obtained.
In the composite 40, each of the openings of the through hole 21 on one surface side of the insulating sheet body 20 is formed by the insulating resin layer 2.
5 is closed by a thin metal layer 35A through the metal layer 5.

In the first step described above, the means for integrally providing the insulating sheet body 20 on the insulating resin film 25A includes a polymer which is cured and becomes an elastic polymer substance on the insulating resin film 25A. Means for applying and curing the material forming material, means for applying heat and pressure to the insulating resin film 25A and the insulating sheet body 20, and the like can be used. In addition, as a means for forming a hole in the laminated body 40A, a means by laser processing, a means by dry etching, or the like can be used.

[Second Step] In this second step, as shown in FIGS. 7 and 8, the hole 41 of the composite 40 including the through hole 21 of the insulating sheet 20 is filled into the hole 41. This is a step of forming the conductive path element material layer 30A in the completed state. Specifically, as shown in FIG. 7, the above-described material for the conductive path element is applied to the other surface of the insulating sheet body 20 in the composite 40, so that the inside of each of the holes 41 of the composite 40 is Is filled with a material for a conductive path element.
As shown in FIG.
OA is formed. Thereafter, if necessary, the conductive path element material attached to the other surface of the insulating sheet body 20 is removed with a squeegee or the like. In the above description, as a means for applying the conductive path element material, a means by printing such as screen printing can be used.

In the second step, for example, 1
× 10 ⁻³ atm or less, preferably 1 × 10 ⁻⁴ to 1 × 10
After applying a conductive path element material to the other surface of the insulating sheet body 20 in the composite 40 under an atmosphere reduced to ^-5 atm, the atmospheric pressure is increased to, for example, normal pressure, thereby obtaining a conductive path. It is preferable to form the element material layer 30A. According to such a method, the material for the conductive path element is densely filled in the hole 41 due to a difference from the pressure in the hole 41 in the composite 40 by increasing the atmospheric pressure. In addition, it is possible to prevent bubbles from being generated in the conductive path element material layer 30A.

[Third Step] In this third step, as shown in FIGS. 9 and 10, the conductive path element material layer 30A in a state of being filled in the hole 41 of the composite 40 is cured. As a result, the insulating sheet body 20 in the composite 40
This is a step of forming the conductive path element 30 integrally provided in a state filled in the through hole. Specifically, as shown in FIG. 9, a composite 40 in which a conductive path element material layer 30A is formed in a hole 41 is disposed between a pair of electromagnets 45 and 46. Is activated, a parallel magnetic field acts in the thickness direction of the conductive path element material layer 30A, and as a result, the conductive particles dispersed in the conductive path element material layer 30A are removed. 30A
Oriented in the thickness direction. In this state, by curing the conductive layer element material layer 30A, as shown in FIG. 10, the conductive path element is formed in the hole 41 of the composite 40 including the through hole 21 of the insulating sheet member 20. 30 are formed.

In the above third step, the hardening treatment of the conductive path element material layer 30A can be performed with the parallel magnetic field applied, but can also be performed after the parallel magnetic field is stopped. it can. The intensity of the parallel magnetic field applied to the conductive layer element material layer 30A is 200 to 1000 on average.
A size of 0 Gauss is preferable.

The curing treatment of the conductive path element material layer 30A is as follows.
Although it is appropriately selected depending on the material used, it is usually performed by a heat treatment. In the case where the conductive path element material layer 30A is cured by heating, the electromagnets 45 and 46 may be provided with heaters. The specific heating temperature and heating time are appropriately selected in consideration of the type of the polymer substance forming material constituting the conductive path element material layer 30A, the time required for the movement of the conductive particles, and the like.

After the third step is completed, as shown in FIG. 11, a resist layer 42 is formed on the surface of the thin metal layer 35A where the conductive path element 30 is located. After removing the portion where the resist layer 42 is not formed by etching, the resist layer 42 is peeled off, whereby the anisotropic conductive sheet 10 having the configuration shown in FIG. 1 is manufactured.

According to the manufacturing method described above, the conductive path element material layer 30A filled in the through-holes 21 of the insulating sheet body 20 is cured so that the through-holes 21 of the insulating sheet body 20 are hardened. Since the conductive path element 30 integrally provided in a state in which the inside is filled is surely formed, FIG.
The anisotropic conductive sheet 10 having the following configuration can be advantageously produced.

The embodiment of the present invention has been described above.
In the present invention, the present invention is not limited to the above embodiment, and various changes can be made .

Further, as shown in FIG. 12, a projection 36 made of metal can be provided on the metal layer 35. When such a protrusion 36 is provided, the thickness of the protrusion 36 is preferably 10 to 500 μm, and more preferably 20 to 300 μm. According to such a configuration, the protruding portion 3 protruding from the surface of the anisotropic conductive sheet 10 on one end surface of the conductive path element 30 via the metal layer 35.
6, the electrical connection between the electrode 2 to be inspected of the circuit board 1 to be inspected and the conductive path element 30 can be more reliably achieved.

Further, as shown in FIG.
A metal layer 37 can be provided so as to cover the other end surface of the zero. According to such a configuration, the other end surface of the conductive path element 30 does not come into contact with the connection electrode 4 of the inspection circuit board 3, so that the conductive polymer is contained in the elastic polymer material constituting the conductive path element 30. It is possible to reliably prevent the surface of the connection electrode 4 of the test circuit board 3 from being contaminated by the low molecular weight component.

[0051]

EXAMPLES The present invention will now be described by way of specific examples, which should not be construed as limiting the invention thereto.

Embodiment 1 According to the configuration shown in FIG. 1, an anisotropic conductive sheet (inspection of a circuit board on which a large number of electrodes to be inspected having a minimum size of 40 μm and an arrangement pitch of minimum 80 μm) are formed. 10) was produced as follows.

[Preparation of material for conductive path element] Addition type silicone rubber "1206RTV (manufactured by Shin-Etsu Chemical Co., Ltd.)"
A conductive path element material was prepared by adding and mixing the following conductive particles at a volume fraction of 33%.

Conductive particles: Nickel particles having an average particle diameter of 10 μm are used as core particles, and the core particles are coated with 4% by weight of gold by chemical plating.

In the preparation of the above-mentioned material for the conductive path element, "Cat-RQ" (manufactured by Shin-Etsu Chemical Co., Ltd.) was used as a curing catalyst at a ratio of 4% by weight of the addition type silicone rubber.

[First Step] An insulating resin film (25A) made of polyimide having a thickness of 60 μm and having a thin metal layer (35) made of copper having a thickness of 15 μm on one surface is prepared. Thin metal layer 35)
On the other surface where is not formed, the following polymer material forming composition is applied to form an insulating sheet body forming layer having a thickness of 0.275 mm, with respect to this insulating sheet body forming layer. By performing a curing treatment at 100 ° C. for 1 hour, the insulating resin layer (2) is formed on one surface of the insulating sheet (20).
5) and a thin metal layer (35A) were laminated in this order to obtain a laminate (40A) (see FIGS. 4 and 5).

The laminated sheet (40A) is subjected to hole processing using a laser device to thereby form an insulating sheet (2A).
0) and a hole (41) penetrating the insulating resin layer (25) and not penetrating the thin metal layer (35A), thereby forming a hole corresponding to the electrode to be inspected of the circuit board to be inspected. An insulating sheet body (20) in which a large number of through holes (21) are formed;
0) Insulating resin layer (25) provided to cover one surface
And a composite (40) comprising a thin metal layer (35A) provided on the surface of the insulating resin layer (25) (FIG. 6).
reference).

[Second step] The prepared material for the conductive path element is screened on the other surface of the insulating sheet body (20) in the composite (40) under a reduced pressure of 1 × 10 ⁻⁴ atm in an atmosphere. After application by printing, the atmosphere pressure is raised to normal pressure, thereby filling the inside of each of the holes (41) of the composite (40) with the material for the conductive path element. 41), a conductive layer element material layer (30A) was formed (see FIGS. 7 and 8). Thereafter, the conductive path element material attached to the other surface of the insulating sheet body (20) was removed with a squeegee.

[Third Step] The composite 40 having the conductive path element material layer (30A) formed in the hole (41) is disposed between a pair of electromagnets (45, 46) having a heater. ,
By operating the electromagnets (45, 46), an average of 500 in the thickness direction of the conductive path element material layer (30A) is obtained.
By performing a heat treatment at 100 ° C. for 1 hour while a parallel magnetic field of 0 Gauss acts, the hole (4) of the composite (40) is
A conductive path element (30) was formed in 1).

After the completion of the third step, the thin metal layer (35)
A resist layer (42) is formed at a position where the conductive path element (30) is located on the surface of A), and a thin metal layer (35A) is formed.
After the portion where the resist layer (42) is not formed is removed by etching, the resist layer (42) is removed.
Was peeled off to produce an anisotropic conductive sheet (10) having the configuration shown in FIG.

The anisotropic conductive sheet (10) described above is interposed between the circuit board (1) to be inspected and the circuit board for inspection (3) (see FIG. 3). When the electrical connection between the electrode under test (2) and the connection electrode (4) of the test circuit board (3) was examined, all the electrodes under test (2) and the connection electrodes (4) were checked. It was confirmed that the electrical connection between them was sufficiently achieved. Inspection of the circuit board (1) to be inspected was repeated 100 times, and immediately after that, the circuit board (1) to be inspected was observed.
The circuit board to be inspected (1) and the electrode to be inspected (2)
No contamination on the surface was observed.

Comparative Example 1 An unevenly distributed anisotropic conductive elastomer sheet for inspecting a circuit board having a large number of electrodes to be inspected having a minimum dimension of 40 μm and a minimum arrangement pitch of 80 μm is shown in FIGS. Prepared according to No. 15. In addition, as the anisotropic conductive elastomer material, addition type silicone rubber “1206RTV (manufactured by Shin-Etsu Chemical Co., Ltd.)”
The same conductive particles as those used in Example 1 were added at a ratio of 15% by volume, and "C
at-RQ (manufactured by Shin-Etsu Chemical Co., Ltd.) was added at a ratio of 4% by weight of the addition-type silicone rubber.
The heating was performed at a heating temperature of 100 ° C., a heating time of one hour, and a parallel magnetic field of 5000 Gauss on average.

The unevenly distributed anisotropic conductive elastomer sheet described above is interposed between the circuit board to be inspected and the circuit board for inspection, so that the electrode to be inspected of the circuit board to be inspected and the connection electrode of the circuit board to be inspected are connected. When the electrical connection between the electrodes was examined, the electrical connection between the electrode to be inspected and the connection electrode arranged at a pitch of 100 μm or less was achieved, but the insulation between the adjacent connection electrodes was Was not secured. Inspection of the circuit board to be inspected was repeated 100 times, and the circuit board to be inspected immediately after was inspected. As a result, contamination of the surface of the circuit board to be inspected and the surface of the electrode to be inspected (2) with oil-like components was observed. Admitted.

[0064]

According to the anisotropic conductive sheet obtained by the present invention , since the conductive path elements are integrally provided in a large number of through holes formed in the insulating sheet, the insulating sheet is provided. The arrangement pattern of the conductive path elements is determined according to the pattern of the through holes. The formation of the through holes in the insulating sheet body can be easily performed even if the pitch is extremely small. Therefore, even when the arrangement pitch of the electrodes to be connected is extremely small, by forming the through holes of the pattern corresponding to the arrangement pattern of the electrodes to be connected on the insulating sheet body, it is possible to correspond to the arrangement pattern of the electrodes. The conductive path elements are arranged in accordance with the pattern, and each of the conductive path elements is provided in a state in which they are insulated from each other by the insulating sheet body. Connection can be reliably achieved.

Further, the insulating sheet body is provided with an insulating resin layer so as to cover one surface thereof, and the conductive path element is provided with a metal layer so as to cover one end surface on one surface side of the insulating sheet body. For example, since the insulating sheet and the conductive path element do not come into contact with the electronic component and its electrode, the electronic component is formed by the low molecular weight component contained in the elastic polymer material constituting the insulating sheet and the conductive path element. In addition, it is possible to reliably prevent the surface of the electrode from being contaminated.

According to the manufacturing method of the present invention, the material layer for the conductive path element filled in the through hole of the insulating sheet body is cured to thereby fill the through hole of the insulating sheet body. Since the conductive path element integrally provided in the folded state is reliably formed, an anisotropic conductive sheet having a specific configuration can be advantageously manufactured.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing a configuration of an example of an anisotropic conductive sheet obtained by the present invention.

FIG. 2 is an explanatory sectional view showing a part of the anisotropic conductive sheet of FIG. 1 in an enlarged manner.

FIG. 3 is an explanatory view showing a state in which the anisotropic conductive sheet shown in FIG. 1 is interposed between a circuit board to be inspected and a circuit board for inspection.

FIG. 4 is an explanatory sectional view showing an insulating resin film having a thin metal layer on one surface, which is used for manufacturing the anisotropic conductive sheet shown in FIG. 1;

FIG. 5 is an explanatory sectional view showing a laminate in which an insulating sheet body is integrally formed on the insulating resin film shown in FIG. 4;

6 is an explanatory cross-sectional view showing a composite body in which a hole is formed in the laminate shown in FIG.

FIG. 7 is an explanatory cross-sectional view showing a state in which a conductive path element material is applied to the surface of the composite.

FIG. 8 is an explanatory cross-sectional view showing a state in which a conductive layer element material layer is formed in a hole of a composite.

FIG. 9 is an explanatory cross-sectional view showing a state in which a parallel magnetic field is applied to a conductive path element material layer formed in a hole of a composite.

FIG. 10 is an explanatory cross-sectional view showing a state where a conductive path element is integrally provided in a hole of a composite.

FIG. 11 is an explanatory sectional view showing a state in which a resist layer is provided on a thin metal layer.

FIG. 12 is an explanatory cross-sectional view showing a partially enlarged configuration of another example of the anisotropic conductive sheet obtained by the present invention.

FIG. 13 is an explanatory cross-sectional view showing a configuration of still another example of the anisotropic conductive sheet obtained by the present invention.

FIG. 14 is an explanatory cross-sectional view showing a state in which an anisotropic conductive elastomer forming material layer is formed between one mold and the other mold used for manufacturing a conventional anisotropic conductive elastomer sheet. It is.

FIG. 15 is an explanatory cross-sectional view showing a state where a parallel magnetic field is applied to the anisotropic conductive elastomer forming material layer.

FIG. 16 is an explanatory sectional view showing a configuration of an example of a conventional anisotropic conductive elastomer sheet.

FIG. 17 is an explanatory cross-sectional view showing a direction of a magnetic field applied to the anisotropic conductive elastomer forming material layer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Inspection circuit board 2 Inspection electrode 3 Inspection circuit board 4 Connection electrode 5 Terminal electrode 10 Anisotropic conductive sheet 20 Insulating sheet body 21 Through hole 25 Insulating resin layer 25A Insulating resin film 30 Conductive circuit element 30A Conductive path element material layer 35 Metal layer 35A Metal thin layer 36 Projection 37 Metal layer 40 Composite 40A Stack 41 Hole 42 Resist layer 45, 46 Electromagnet 80 One mold (upper mold) 85 The other mold (lower mold) ) 81, 81a,
81b Ferromagnetic part 82 Non-magnetic part 86, 86a,
86b Ferromagnetic portion 87 Nonmagnetic portion 90 Anisotropically conductive elastomer sheet 90A Anisotropically conductive elastomer forming material 91 Conductive path forming portion 82 Insulating portion E Elastic polymer substance P Conductive particles

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-60930 (JP, A) JP-A-9-292411 (JP, A) JP-A-7-105741 (JP, A) JP-A-5-205 JP-A-6-265575 (JP, A) JP-A-6-240217 (JP, A) JP-A-6-249924 (JP, A) JP-A-4-151889 (JP, A) 54-183686 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01R 43/00 H01R 11/01 501

Claims (4)

(57) [Claims] 1. An insulating resin layer and an insulating resin layer on one surface of an insulating sheet body.
And a laminated body in which thin metal layers are laminated in this order,
While penetrating the insulating sheet body and the insulating resin layer, gold
By forming holes that do not penetrate the thin layer,
An insulating sheet body having a through hole formed therein, and the insulating sheet
An insulating resin layer provided to cover one surface of the
A composite consisting of a thin metal layer provided on the surface of an insulating resin layer
A first step of producing a united body, and a cured and elastic
Conductive particles in the polymer material forming material
Is applied to the material for the fluidic conductive path element in which is dispersed
A conductive path element is provided inside each of the through holes of the composite.
Material, which allows each of the through holes to have a conductive path element.
A second step of forming a child material layer, and applying a parallel magnetic field in the thickness direction of the conductive path element material layer.
Conductive particles are oriented in the thickness direction of the material layer for the conductive path element
And curing the conductive layer element material layer.
And the third step of forming the conductive path element in the through hole
A method of manufacturing an anisotropic conductive sheet characterized by being performed
Law. 2. An insulating system under a reduced pressure atmosphere.
Each opening of the through hole on one side of the sheet body is a thin metal layer
The other surface of the insulating sheet body is sealed by
Material for conductive path element, then increase atmospheric pressure
By doing so, each of the through holes of the insulating sheet body
Material layer for conductive path element filled in the through hole
Forming the second step is performed.
The method for producing an anisotropic conductive sheet according to claim 1. 3. After the third step, conductive paths in the thin metal layer
Removal of parts other than where the element is located is performed.
The difference according to claim 1 or 2, wherein
A method for producing a conductive sheet. 4. The method according to claim 1, wherein
Characterized by being manufactured by a manufacturing method.
Anisotropic conductive sheet.