JP2000243486A - Anisotropic conductive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anisotropic conductive sheet capable of surely achieving required electrical connection and having a long service life even in the event that it is repeatedly used in such an environment that it undergoes a heat history of changing temperatures. SOLUTION: This anisotropic conductive sheet is equipped with an insulating sheet body 10 having through holes 11 formed therein and extending in the thickness direction and conductive passage elements 20 made up by including conductive particles in an elastic polymeric material packed in the respective through holes 11 of the insulating sheet body 10, and the insulating sheet body 10 is made up of an elastic polymeric material having a small coefficient of thermal expansion. Preferably, a thermal-expansion suppressing sheet body 15 made of an insulating material having a small coefficient of thermal expansion is integrally provided with one surface of the insulating sheet body 10, and a tensile force is exerted on the insulating sheet body 10 in a surface direction thereof by the thermal-expansion suppressing sheet body 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anisotropic conductive material which is preferably used as a connector in an electrical connection between circuit devices such as electronic parts and an inspection device for circuit devices such as printed circuit boards and semiconductor integrated circuits. It is about a sheet.

[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 devices, for example, a printed circuit board and a leadless chip carrier, a liquid crystal panel, etc. ing.

In electrical inspection of a circuit device such as a printed circuit board or a semiconductor integrated circuit, an electrode to be inspected formed on one surface of a circuit device to be inspected and an electrode formed on the surface of the inspection circuit substrate. In order to achieve electrical connection with the test electrode, an anisotropic conductive elastomer sheet is interposed between the test electrode region of the circuit device and the test electrode region of the test circuit board. I have.

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 for a circuit device or the like in which electrodes to be connected are arranged at a small pitch. The one formed so as to protrude from the insulating portion is more preferable because the contact with the electrode to be inspected is surely performed.

However, when the conventional unevenly distributed anisotropic conductive elastomer sheet is used for electrical inspection of a circuit device such as a semiconductor integrated circuit, the following problems have been found. In the electrical inspection of the circuit device, an electrode to be inspected of the circuit device to be inspected is brought into contact with one surface of the conductive path forming portion of the anisotropic conductive elastomer sheet, and the other surface of the conductive path forming portion is inspected. The required electrical connection is achieved by bringing the test electrodes of the circuit board into contact with each other and further pressing the test electrodes in the thickness direction of the anisotropic conductive elastomer sheet. At this time, in the anisotropic conductive elastomer sheet, a large pressure is applied to the conductive path forming portion in the thickness direction by being pressed by the electrode to be inspected of the circuit device to be inspected, and is maintained in this state.

The electrical inspection of a semiconductor integrated circuit is generally performed in a high-temperature environment in order to develop a potential defect of the semiconductor integrated circuit. However, the material forming the anisotropically conductive elastomer sheet, particularly the coefficient of thermal expansion of the elastic body forming the insulating portion thereof, depends on the material forming the connected surface of the semiconductor integrated circuit with which the anisotropically conductive elastomer sheet is brought into contact. When the semiconductor integrated circuit is pressed against the anisotropic conductive elastomer sheet and the anisotropic conductive elastomer sheet has received a thermal history due to a temperature change, the temperature of the semiconductor integrated circuit is significantly larger than the thermal expansion coefficient of the semiconductor integrated circuit. Due to the difference in the coefficient of thermal expansion with the material constituting the connected surface,
Free thermal expansion in the surface direction of the insulating portion of the anisotropic conductive elastomer sheet is impeded by the surface to be connected of the semiconductor integrated circuit, and as a result, large internal distortion occurs in the insulating portion. Then, due to the internal strain of the insulating portion, a considerably large pressure is applied to the conductive path forming portion in the surface direction.

As described above, when an anisotropically conductive elastomer sheet is used for electrical inspection of a circuit device in an environment subjected to a thermal history due to a temperature change, the conductive path of the anisotropically conductive elastomer sheet is formed. Since a considerable pressure is applied not only to the thickness direction but also to the surface direction, the conductive path forming portion of the anisotropic conductive elastomer sheet is damaged at an early stage when the member is used repeatedly. No connection.

[0009]

DISCLOSURE OF THE INVENTION The present invention has been made based on the above circumstances, and its object is to provide:
It is an object of the present invention to provide an anisotropic conductive sheet capable of reliably achieving a required electrical connection even when repeatedly used in an environment which receives a heat history due to a temperature change and having a long service life.

[0010]

An anisotropic conductive sheet according to the present invention comprises: an insulating sheet body having a plurality of through holes extending in a thickness direction; and a through hole of the insulating sheet body. A conductive path element in which conductive particles are contained in an elastic polymer material integrally provided in a state of being filled in the through hole, wherein the insulating sheet body has a coefficient of thermal expansion. It is characterized by being made of a small elastic polymer material.

In the anisotropic conductive sheet of the present invention, the elastic polymer material constituting the insulating sheet preferably has a coefficient of thermal expansion of 4 × 10 ⁻⁵ / ° C. or less. Also,
When the coefficient of thermal expansion of the elastic polymer material constituting the insulating sheet body is A, and the coefficient of thermal expansion of the material forming the surface to be connected in the circuit device to be connected is B, the value of | AB | It is preferably at most 2 × 10 ⁻⁵ / ° C. Further, it is preferable that the insulating sheet is made of an elastic polymer material in which 10 to 60 parts by weight of a filler for suppressing thermal expansion is dispersed in 100 parts by weight of an elastic polymer material.
Further, on at least one surface of the insulating sheet body, a thermal expansion suppressing sheet body made of an insulating material having a small thermal expansion coefficient is provided integrally, and by using the thermal expansion suppressing sheet body, the insulating sheet body is provided. Is preferably tensioned in the plane direction.

[0012]

(1) By providing the conductive path element in the through-hole of the insulating sheet made of an elastic polymer material having a small coefficient of thermal expansion, even if it receives a heat history due to a temperature change, Because the thermal expansion of the insulating sheet body is small,
A large pressure is not applied to the conductive path element in the surface direction. In particular, by using an elastic polymer material having a thermal expansion coefficient similar to the material forming the connection surface of the circuit device to be connected as the material forming the insulating sheet body, the connection surface of the semiconductor integrated circuit is used. Since the thermal expansion in the surface direction of the insulating sheet body is not hindered by this, the stress applied to the conductive path element in the surface direction is reliably suppressed. (2) A thermal expansion suppressing sheet made of an insulating material having a small thermal expansion coefficient is integrally provided on the upper surface of the insulating sheet, and the thermal expansion suppressing sheet is used to form a surface on the insulating sheet. Even if a thermal history due to a temperature change is received by applying a tension in the direction, a change in the tension applied to the insulating sheet body causes a substantial change in the surface direction of the insulating sheet body. As a result, the pressure applied to the conductive path element in the surface direction is further suppressed.

[0013]

Embodiments of the present invention will be described below in detail. <First Embodiment> FIG. 1 is an explanatory sectional view showing the structure of a main part of an anisotropic conductive sheet according to a first embodiment of the present invention. This anisotropic conductive sheet is provided with an insulating sheet body 10 in which a large number of through holes 11 are formed extending in the thickness direction in accordance with a specific pattern. The specific pattern in the through hole 11 of the insulating sheet body 10 is a pattern corresponding to the pattern of the electrode to be connected. In each of the through holes 11 of the insulating sheet body 10, a conductive path element 20 is provided integrally with the insulating sheet body 10 in a state where the conductive path element 20 is filled in the through hole 11. Are substantially independent of each other. On the upper surface of the insulating sheet body 10,
Thermal expansion suppressing sheet body 15 is provided integrally,
With the thermal expansion suppressing sheet member 15, tension is applied to the insulating sheet member 15 in the surface direction. Also,
In the anisotropic conductive sheet of this example, the conductive path element 20
Is formed such that its upper surface slightly protrudes from the upper surface of the thermal expansion suppressing sheet member 15 and its lower surface protrudes slightly from the lower surface of the insulating sheet member 10.

The insulating sheet 10 is made of an elastic polymer material having a small coefficient of thermal expansion. In particular,
The elastic polymer material has a coefficient of thermal expansion of 4 × 10 ^-5 /
° C or less is preferably used, so that the conductive path element 20
The stress applied in the plane direction can be suppressed. Further, as the elastic polymer material constituting the insulating sheet body 10, the coefficient of thermal expansion of the elastic polymer material is A, and the connected surface of the connected circuit device to which the anisotropic conductive sheet is in contact is connected. When the coefficient of thermal expansion of the material to be formed is B,
The value of | AB | is preferably 2 × 10 ⁻⁵ / ° C. or less. When this value is excessive, when the anisotropic conductive sheet receives a heat history due to a temperature change in a state of being electrically connected to the circuit device, the conductive path element 20 corresponds to the surface direction. Since a large pressure is applied to the conductive path element 20, the conductive path element 20 is easily damaged at an early stage.

The specific numerical values of the coefficient of thermal expansion of the elastic polymer material constituting the insulating sheet body 10 are as follows. When the material forming the surface to be connected in the circuit device to be connected is a thermosetting resin material. Has a coefficient of thermal expansion of 1 × 10 ⁻⁵ to
An elastic polymer material of 2.5 × 10 ⁻⁵ / ° C. can be used. When the material forming the connection surface is a low thermal expansion inorganic material such as ceramics, the thermal expansion coefficient is 3 × 10 5
An elastic polymer material of ^-6 to 1 x ^10-5 / ° C can be used.

As such an elastic polymer material, an elastic polymer material containing a filler for suppressing thermal expansion can be used. Curable polymer material forming materials that can be used to obtain such an elastic polymer material include polybutadiene rubber, natural rubber, polyisoprene rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, and the like. Conjugated diene rubbers and hydrogenated products thereof, styrene-butadiene-diene block copolymer rubbers, block copolymer rubbers such as styrene-isoprene block copolymers and hydrogenated products thereof, chloroprene, urethane rubber, polyester Base rubber, epichlorohydrin rubber, silicone rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, and the like.If the obtained anisotropic conductive sheet is required to have weather resistance, it may be conjugated. Use other than diene rubber Preferred.

The filler for suppressing thermal expansion is not particularly limited as long as it can suppress the thermal expansion of the elastic polymer used. In addition, the shape may be various shapes such as a spherical shape, a fibrous shape, and a scaly shape, and from the viewpoint of suppressing deterioration during heating and pressurizing, a spherical shape may be used. preferable. Specific examples of the filler for suppressing thermal expansion include silica, alumina, talc, red iron oxide, and silicon nitride.

The ratio of the thermal expansion suppressing filler in the elastic polymer material is 1 to 100 parts by weight of the elastic polymer material.
It is preferably 0 to 60 parts by weight, particularly preferably 20 to 40 parts by weight. If this proportion is less than 10 parts by weight,
It becomes difficult to obtain an elastic polymer material having an intended coefficient of thermal expansion. On the other hand, if this proportion exceeds 60 parts by weight, the resulting elastic polymer material is fragile and tends to have a high elastic modulus, so that it is difficult to obtain the insulating sheet body 10 having the necessary strength and elasticity. Becomes

The thickness of the insulating sheet 10 is, for example, 0.1 to 2 mm, preferably 0.2 to 1 mm.

The conductive path element 20 is composed of an elastic polymer material containing conductive particles, and preferably, the conductive particles are oriented in the elastic polymer material in a state of being arranged in the thickness direction. A conductive path is formed in the thickness direction of the conductive path element 20 by the conductive particles. This conductive path element 20
May be a pressurized conductive path element in which a conductive path is formed by reducing the resistance value when pressed and compressed in the thickness direction. Further, the conductive path of the conductive path element 20 may be formed over the entire area thereof in a cross section perpendicular to the thickness direction of the conductive path element 20, or may be formed only in a part of the area, for example, only the central area.

As the insulating elastic high molecular substance used for the conductive path element 20, a high molecular substance having a crosslinked structure is preferable. Various materials can be used as the curable polymer material forming material that can be used to obtain such an elastic polymer material. Specific examples thereof include polybutadiene rubber, natural rubber, and polyisoprene rubber. Styrene-butadiene copolymer rubber, 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, Examples include chloroprene, 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, particularly from the viewpoint of moldability and electrical properties.
It is preferable to use silicone rubber.

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; hereinafter the same) 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.
The cyclic siloxane is anionically polymerized in the presence of a catalyst, and a polymerization terminator such as dimethylhydrochlorosilane, methyldihydrochlorosilane or dimethylhydroalkoxysilane is used. Other reaction conditions (for example, the amount of the cyclic siloxane and the polymerization termination) 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.

As the conductive particles used in 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 iron, cobalt, particles of metals exhibiting magnetism such as nickel, particles of alloys thereof, particles containing these metals, or particles containing these metals as core particles. The core particles are obtained by plating the surface of a core particle with a metal having good conductivity such as gold, silver, palladium, and rhodium, or inorganic particles or polymer particles such as nonmagnetic metal particles or glass beads as core particles. Examples thereof include a particle obtained by plating the surface of a particle with a conductive magnetic material such as nickel and cobalt, and a particle obtained by coating a core particle 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 those obtained by plating the surface with a metal having good conductivity such as gold or silver, and in particular, 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 to
It is 20% by weight, more preferably 3.5 to 15% by weight, particularly preferably 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 particle diameter of the conductive particles is 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 obtained conductive path element 20 can be easily deformed under pressure, and sufficient electrical contact between the conductive particles in the conductive path element 20 can be obtained. In addition, the shape of the conductive particles is not particularly limited. However, since the conductive particles can be easily dispersed in the polymer substance-forming material, the conductive particles have a spherical shape, a star shape, or a secondary shape in which these are aggregated. It is preferably a lump formed by particles.

The water content of the conductive particles is preferably 5% or less, more preferably 3% or less, further preferably 2% or less, and particularly preferably 1% or less. 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 20 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%, based on the polymer material forming material.
Preferably, it is used at a ratio of up to 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.

The thermal expansion suppressing sheet member 15 is made of a material having a small thermal expansion coefficient. Specifically, it is preferable to use one having a thermal expansion coefficient of 2.5 × 10 ⁻⁵ / ° C. or less. As a material constituting the thermal expansion suppressing sheet member 15, the thermal expansion coefficient is C, and the thermal expansion coefficient of the material forming the connected surface with which the anisotropic conductive sheet in the connected circuit device is in contact. Is | B, | CB
Is preferably 1 × 10 ⁻⁵ / ° C. or less. To give specific numerical values of the thermal expansion coefficient of the material constituting the thermal expansion suppressing sheet member 15, when the material forming the connected surface in the connected circuit device is a thermosetting resin material, When a material having an expansion coefficient of 1 × 10 ^{−5 to} 2.5 × 10 ⁻⁵ / ° C. can be used, and the material forming the connection surface is a low thermal expansion inorganic material such as ceramics,
A material having a coefficient of thermal expansion of 3 × 10 ⁻⁶ to 1 × 10 ⁻⁵ / ° C. can be used. Such a sheet member 15 for suppressing thermal expansion.
As a specific example of the material constituting, there are a polyimide resin, a glass fiber-containing epoxy resin, a phenol resin, a glass fiber-containing phenol resin, and the like. The thickness of the thermal expansion suppressing sheet body 15 is, for example, 0.01
~ 0.5mm, preferably 0.05 ~ 0.2mm
It is.

The magnitude of the surface tension applied to the insulating sheet member 10 by the thermal expansion suppressing sheet member 15 depends on the coefficient of thermal expansion of the elastic polymer material constituting the insulating sheet member 10 and the anisotropic conductivity. It is appropriately set in accordance with the environmental temperature at which the sheet is used, and is particularly large enough to exert a tension on the insulating sheet body 10 even under the highest temperature environment in which the anisotropic conductive sheet is used. Is preferred.

The above anisotropic conductive sheet can be manufactured, for example, as follows. First, as shown in FIG. 2, a thermal expansion suppressing sheet body 15 is laminated on the upper surface of the insulating sheet body 10, and the thermal expansion suppressing sheet body 1 is further laminated.
5, one protective layer 16 and the other protective layer are laminated on the lower surface of the insulating sheet member 10, and the thermal expansion suppressing sheet member 15 exerts a tension in the surface direction of the insulating sheet member 10. The manufactured intermediate laminated body 1 is produced. Next, as shown in FIG. 3, holes 1 </ b> A penetrating in the thickness direction of the intermediate laminate 1 are formed in the intermediate laminate 1 in accordance with the arrangement pattern of the conductive path elements to be formed. Then, as shown in FIG. 4, a conductive path element material in which conductive magnetic particles are dispersed in a polymer material forming material which is cured to become an elastic polymer material in the hole 1A of the intermediate laminate 1 To form the conductive path element material layer 20 </ b> A in the hole 1 </ b> A of the intermediate laminate 1.

In the above, the intermediate laminate 1 can be produced, for example, as follows. One protective layer 1
A polymer-forming material layer is formed by applying a liquid polymer-forming material that is cured to become an elastic polymer material on a thermal expansion suppressing sheet body 15 provided integrally with the polymer-forming material 6. After the other protective layer 17 is laminated on the forming material layer, a curing treatment of the polymer forming material layer is performed by hot pressing or the like, whereby the intermediate laminate 1 shown in FIG.
Is obtained.

As a method of forming the hole 1A in the intermediate laminate 1, a method by laser processing, a method by press processing, a method by drill processing, or the like can be used. Further, as a method for filling the hole 1A of the intermediate laminate 1 with the conductive path element material, a printing method such as screen printing, a roll press-fitting method, or the like can be used.

The material for the conductive path element may contain a curing catalyst for curing the polymer substance 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 which can be used as a catalyst for the hydrosilylation reaction include chloroplatinic acid and salts thereof, a platinum-unsaturated group-containing siloxane complex, a complex of vinylsiloxane and platinum,
Known examples include a complex of platinum and 1,3-divinyltetramethyldisiloxane, a complex of triorganophosphine or phosphite and platinum, an acetylacetate platinum chelate, and a complex of cyclic diene and platinum. The amount of curing catalyst used is
It is appropriately selected in consideration of the type of the polymer-forming material, the type of the curing catalyst, and other curing treatment conditions, and is usually 3 to 15 parts by weight based on 100 parts by weight of the polymer-forming material.

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.

Next, as shown in FIG.
, One pole plate 50 is arranged on the upper surface, the other pole plate 55 is arranged on the lower surface of the intermediate laminated body 1, and a pair of pole plates are arranged on the upper surface of the one pole plate 50 and the lower surface of the other pole plate 55. The electromagnets 51 and 56 are arranged. Here, one magnetic pole plate 50 has a ferromagnetic portion M formed according to a pattern opposite to the arrangement pattern of the conductive path elements 20 to be formed,
A non-magnetic portion N is formed in a portion other than the ferromagnetic portion M, and each of the ferromagnetic portions M is arranged so as to be located above the corresponding conductive path element material layer 20A. You. On the other pole plate 55, a ferromagnetic portion M is formed in accordance with the same pattern as the arrangement pattern of the conductive path elements 20 to be formed. Each of the ferromagnetic portions M is formed so as to correspond to the corresponding conductive path element material layer 20.
A is disposed below A.

One pole plate 50 and the other pole plate 55
As a material constituting the ferromagnetic portion M in each of the above, iron, nickel, cobalt, or an alloy thereof can be used. In addition, as a material forming the nonmagnetic portion N in each of the one magnetic pole plate 50 and the other magnetic pole plate 55, a nonmagnetic metal such as copper, a heat-resistant resin such as polyimide, or the like can be used.

By operating the electromagnets 51 and 56, a parallel magnetic field acts in a direction from the ferromagnetic portion M of the one pole plate 50 to the corresponding ferromagnetic portion M of the other pole plate 55. I do. As a result, in the conductive path element material layer 20A, the conductive path element material layer 20A is formed.
The conductive magnetic particles dispersed in the ferromagnetic portion M of one pole plate 50 and the corresponding magnetic pole plate 5
5 and is more preferably oriented in the thickness direction of the conductive path element material layer 20A. Then, in this state, by curing the conductive path element material layer 10A, the conductive path element 20 is integrally formed in the hole 1A of the intermediate laminate 1 as shown in FIG.

In the above, the conductive path element material layer 20A
Can be performed with the parallel magnetic field applied, but can also be performed after the parallel magnetic field is stopped. The strength of the parallel magnetic field applied to the conductive path element material layer 20A is preferably 200 to 10000 gauss on average. As a means for applying a parallel magnetic field, a permanent magnet can be used instead of an electromagnet. As such a permanent magnet, Alnico (Fe-Al-
Ni-Co based alloys), ferrites and the like are preferable. In the conductive path element 20 thus obtained, since the conductive particles are oriented so as to be arranged in the thickness direction of the conductive path element 20, good conductivity can be obtained even if the ratio of the conductive particles is small.

The curing treatment of the conductive path element material layer 20A is as follows.
Although it is appropriately selected depending on the material used, it is usually performed by a heat treatment. When the conductive path element material layer 20A is cured by heating, the electromagnets 51 and 56 may be provided with heaters. The specific heating temperature and heating time are appropriately selected in consideration of the type of the polymer material forming material constituting the conductive path element material layer 20A, the time required for the movement of the conductive magnetic particles, and the like.

According to such a method, the material layer 20A for the conductive path element filled in the hole 1A of the intermediate laminated body 1 including the through hole of the insulating sheet body 10 is cured, whereby the insulation is achieved. The plurality of conductive path elements 20 integrally provided in a state of being filled in the through holes of the conductive sheet body 10 are surely formed.

The intermediate laminated body 1 on which the conductive path element 20 is formed in this manner is divided into one pole plate 50 and the other pole plate 5.
5 and further removed from the sheet 1 for suppressing thermal expansion.
By peeling one protective layer 16 and the other protective layer 17 from the upper surface of 5 and the lower surface of the insulating sheet body 10, an anisotropic conductive sheet having the configuration shown in FIG. 1 is obtained.

In such an anisotropic conductive sheet,
One surface of the conductive path element 20 is brought into contact with, for example, an electrode to be inspected of a circuit device to be inspected, and the other surface of the conductive path element 20 is brought into contact with an inspection electrode of a circuit board for inspection. By pressing in the thickness direction, the electrodes to be inspected of the circuit device to be inspected and the inspection electrodes of the inspection circuit board are electrically connected and held in this state. Then, after raising the environmental temperature from the normal temperature to the inspection execution temperature, a required electrical inspection is performed on the circuit device. At this time, the conductive path element 20 of the anisotropic conductive sheet is pressed by the electrode under test of the circuit device under test, so that pressure is applied in the thickness direction of the conductive path element 20 and the insulating sheet body 10 is pressed. Is thermally expanded, so that pressure is applied in the surface direction of the conductive path element 20.

According to the above-described anisotropic conductive sheet, since the insulating sheet body 10 is made of an elastic polymer material having a small coefficient of thermal expansion, the insulating sheet body 10 may be subjected to a thermal history due to a temperature change. Even if there is, the thermal expansion of the insulating sheet body 10 is small, so that a large pressure is applied to the conductive path element 20 in the surface direction. In particular, by using an elastic polymer material having a thermal expansion coefficient close to the material forming the connection surface of the circuit device under test as a material forming the insulating sheet body 10, the connection surface of the semiconductor integrated circuit is used. Since the thermal expansion in the plane direction of the insulating sheet body 10 is not hindered by this, the stress applied to the conductive path element 20 in the plane direction can be reliably suppressed. Therefore, even if the anisotropic conductive sheet is repeatedly used in an environment that receives a thermal history due to a temperature change, the conductive path element 20 is not damaged at an early stage. And a long service life can be obtained.

A thermal expansion suppressing sheet 15 made of an insulating material having a small coefficient of thermal expansion is integrally provided on the upper surface of the insulating sheet 10, and this thermal expansion suppressing sheet 15 Since tension is applied to the insulating sheet body 10 in the surface direction, even when the insulating sheet body 10 receives a thermal history due to a temperature change, the tension applied to the insulating sheet body 10 changes, thereby Insulating sheet 1
As a result, the substantial thermal expansion in the zero plane direction is reduced,
The pressure applied to the conductive path element 20 in the surface direction can be further suppressed.

<Second Embodiment> FIG. 7 is an explanatory sectional view showing the structure of a main part of an anisotropic conductive sheet according to a second embodiment of the present invention. In this anisotropic conductive sheet, a plurality of through holes 1 extending in the thickness direction according to a specific pattern corresponding to a pattern of an electrode to be connected.
1 is provided, and each of the through holes 11 of the insulating sheet body 10 is provided with a conductive path element 20 in the state where the through hole 11 is filled. 10 and the conductive path element 2
Each of the 0s is substantially independent of each other.
On the upper surface of the insulating sheet body 10, a sheet member 15 for suppressing thermal expansion is provided integrally. With the sheet member 15 for suppressing thermal expansion, tension acts on the insulating sheet body 15 in the surface direction. Have been. In the anisotropic conductive sheet of this example, the upper surface of the conductive path element 20 is located on the same plane as the upper surface of the thermal expansion suppressing sheet member 15, and the lower surface of the conductive path element 20 extends from the lower surface of the insulating sheet member 10. It is formed in a slightly protruding state. The contact metal film 25 is provided so as to protrude from the upper surface of the thermal expansion suppressing sheet member 15 so as to cover the upper surface of the conductive path element 20 and the upper surface of the thermal expansion suppressing sheet member 15 in the periphery thereof. .
In the above, the specific configuration of each of the insulating sheet body 10, the thermal expansion suppressing sheet body 15, and the conductive path element 20 is as follows.
This is the same as the anisotropic conductive sheet according to the first embodiment.

As a metal material constituting the contact metal film 25, copper, gold, rhodium, platinum, palladium, nickel, their plating, or alloys thereof can be used. The thickness of the contact metal film 25 is, for example, 0.005 to 0.5 mm, preferably 0.05 to 0.5 mm.
2 to 0.1 mm.

The above-described anisotropic conductive sheet can be manufactured, for example, as follows. First, as shown in FIG. 8, a sheet member 15 for suppressing thermal expansion and a thin metal layer 25A are laminated in this order on the upper surface of the insulating sheet member 10, and a protective layer 21 is laminated on the lower surface of the insulating sheet member 10. The intermediate laminated body 2 is produced by applying a tension in the surface direction of the insulating sheet body 10 by the thermal expansion suppressing sheet body 15. Next, as shown in FIG.
Then, according to the arrangement pattern of the conductive path elements to be formed, a hole 2A that penetrates the protective layer 21, the insulating sheet body 10, and the thermal expansion suppressing sheet body 15 and does not penetrate the thin metal layer 25A is formed. Then, as shown in FIG.
Filling the hole 2A of the intermediate laminate 2 with a conductive path element material in which conductive magnetic particles are dispersed in a polymer material forming material that is cured to become an elastic polymer material,
The material layer 2 for the conductive path element is formed in the hole 2A of the intermediate laminate 2.
OA is formed.

In the above, the intermediate laminate 2 can be produced, for example, as follows. Thin metal layer 25A
On the thermal expansion suppressing sheet body 15 integrally provided,
A polymer-forming material layer is formed by applying a liquid polymer-forming material that is cured to become an elastic polymer material, and a protective layer 21 is laminated on the polymer-forming material layer. By performing the curing treatment of the molecule forming material layer, an intermediate laminate 2 as shown in FIG. 8 is obtained.
The specific configuration of the conductive path element material is the same as the manufacturing method in the first embodiment.

In the same manner as in the first embodiment, a parallel magnetic field is applied to the conductive path element material layer 20A thus formed, and the conductive path element material layer 20A is formed.
By performing the curing treatment of A, as shown in FIG.
The conductive path element 20 is integrally formed in the hole 2A of the intermediate laminate 2.

Then, the intermediate laminated body 2 on which the conductive path element 20 is formed is taken out from between the one magnetic pole plate 50 and the other magnetic pole plate 55, and as shown in FIG.
By forming a resist layer 18 having a hole 19 at the position where the conductive path element 20 is disposed, and then performing a plating process on the thin metal layer 25A exposed through the hole 19 of the resist layer 18, As shown in FIG. 13, a contact metal film 25 having a required thickness is formed. And the metal thin layer 25
After removing the resist layer 18 formed on A, photolithography and etching are performed to remove a portion of the thin metal layer 25A other than the portion where the contact metal film 25 is formed, and a protective layer 21 is formed. By peeling, an anisotropic conductive sheet having the configuration shown in FIG. 7 is obtained.

In this anisotropic conductive sheet, for example, an electrode to be inspected of a circuit device to be inspected is brought into contact with the contact metal film 25 provided on one surface of the conductive path element 20, The test electrode of the test circuit board is brought into contact with the test electrode of the test circuit board by pressing the test electrode in the thickness direction of the anisotropic conductive sheet. The required electrical connections are achieved.

According to such an anisotropic conductive sheet, the same effects as those of the anisotropic conductive sheet according to the first embodiment can be obtained, and further, the following effects can be obtained. That is, since the contact metal film 25 is formed on the upper surface of the conductive path element 20, even if the electrode to be connected has an oxide film on its surface, the contact metal film 2
5, the oxide film can be broken through, so that the required electrical connection can be reliably achieved. Also,
Since the conductive path element 20 does not directly contact the electrode to be connected, the surface of the electrode may be contaminated by the low molecular weight component contained in the elastic polymer material constituting the conductive path element 20. Absent.

[0056]

According to the anisotropic conductive sheet of the present invention, since the conductive path element is provided in the through hole of the insulating sheet made of an elastic polymer material having a small coefficient of thermal expansion, the temperature change , The thermal expansion of the insulating sheet body is small, so that a large pressure is applied to the conductive path element in the surface direction.
In particular, by using an elastic polymer material having a thermal expansion coefficient similar to that of the material forming the connection surface in the circuit device under test as a material forming the insulating sheet body, the connection surface of the semiconductor integrated circuit can be improved. Since the thermal expansion in the plane direction of the insulating sheet body is not hindered, the stress applied to the conductive path element in the plane direction can be reliably suppressed. Therefore, even when the anisotropic conductive sheet is repeatedly used in an environment that receives a thermal history due to a temperature change, the conductive path element is not damaged at an early stage. And a long service life is obtained.

Further, by applying a tension in the surface direction of the insulating sheet body, a thermal expansion suppressing sheet body made of an insulating material having a small thermal expansion coefficient is provided integrally on the upper surface of the insulating sheet body. Even when receiving a thermal history due to a temperature change, by changing the tension applied to the insulating sheet body, the substantial thermal expansion in the plane direction of the insulating sheet body is reduced, The pressure applied to the conductive path element in the surface direction can be further suppressed.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view illustrating a configuration of a main part of an anisotropic conductive sheet according to a first embodiment.

FIG. 2 is an explanatory cross-sectional view showing a configuration of an intermediate laminate used for manufacturing the anisotropic conductive sheet shown in FIG.

FIG. 3 is an explanatory sectional view showing a state in which holes are formed in the intermediate laminate shown in FIG. 2;

FIG. 4 is an explanatory cross-sectional view showing a state where a conductive path element material layer is formed in a hole of an intermediate laminate.

FIG. 5 is an explanatory cross-sectional view showing a state where a parallel magnetic field is applied to a conductive path element material layer formed in a hole of an intermediate laminate.

FIG. 6 is an explanatory cross-sectional view showing a state where a conductive path element is formed in a hole of an intermediate laminate.

FIG. 7 is an explanatory cross-sectional view illustrating a configuration of a main part of an anisotropic conductive sheet according to a second embodiment.

8 is an explanatory cross-sectional view showing a configuration of an intermediate laminate used for manufacturing the anisotropic conductive sheet shown in FIG.

FIG. 9 is an explanatory sectional view showing a state in which a hole is formed in the intermediate laminate shown in FIG. 8;

FIG. 10 is an explanatory cross-sectional view showing a state where a conductive path element material layer is formed in a hole of an intermediate laminate.

FIG. 11 is an explanatory cross-sectional view showing a state in which a conductive path element is formed in a hole of an intermediate laminate.

FIG. 12 is an explanatory cross-sectional view showing a state in which a resist layer is formed on a thin metal layer in the intermediate laminate.

FIG. 13 is an explanatory sectional view showing a state in which a contact metal film is formed on a conductive path element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Intermediate laminated body 1A hole 2 Intermediate laminated body 2A hole 10 Insulating sheet body 11 Through hole 15 Thermal expansion suppressing sheet 16 One protective layer 17 The other protective layer 18 Resist layer 19 Hole 20 Conductive path element 21 Protective layer Reference Signs List 20A Conductive path element material layer 25 Contact metal film 25A Thin metal layer 50 One magnetic pole plate 51 Electromagnet 55 The other magnetic pole plate 56 Electromagnet M Ferromagnetic part N Nonmagnetic part

Claims (5)

[Claims] An insulating sheet body having a plurality of through holes extending in a thickness direction thereof, and a plurality of through holes of the insulating sheet body provided integrally with the through holes so as to be filled therein. A conductive path element in which conductive particles are contained in the elastic polymer material provided, wherein the insulating sheet body is made of an elastic polymer material having a small coefficient of thermal expansion. Anisotropic conductive sheet. 2. The anisotropic conductive sheet according to claim 1, wherein a coefficient of thermal expansion of the elastic polymer material constituting the insulating sheet body is 4 × 10 ⁻⁵ / ° C. or less. 3. Assuming that the thermal expansion coefficient of the elastic polymer material constituting the insulating sheet body is A and the thermal expansion coefficient of the material forming the connection surface in the connected circuit device is B, | A
The anisotropic conductive sheet according to claim 1, wherein the value of −B | is 2 × 10 ⁻⁵ / ° C. or less. 4. The insulating sheet body is made of an elastic polymer material 10
The anisotropic material according to any one of claims 1 to 3, wherein the material is made of an elastic polymer material in which 10 to 60 parts by weight of a filler for suppressing thermal expansion is dispersed in 0 parts by weight. Conductive sheet. 5. A thermal expansion suppressing sheet made of an insulating material having a small coefficient of thermal expansion is integrally provided on at least one surface of the insulating sheet, and the insulating sheet is provided by the thermal expansion suppressing sheet. The anisotropic conductive sheet according to any one of claims 1 to 4, wherein a tension is applied to the body in the surface direction.