JP2002075063A - Anisotropic conductive sheet - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To show conductivity in a non-pressurized state or in a state of being pressed in a thickness direction with a small force, and in a state of being pressed in a thickness direction with a large force, in a non-pressed state or To provide an anisotropic conductive sheet showing higher conductivity than a state in which the sheet is pressed in a thickness direction with a small force. SOLUTION: The above-mentioned problem is solved by an anisotropic conductive sheet which is made of a conductive elastomer and has a projecting portion on at least one surface. As the conductive elastomer, those obtained by dispersing a conductivity-imparting substance in an insulating elastomer can be used. The conductive elastomer has a volume resistivity of 110 ⁷ to 1 ×.
It is preferably 10 ¹² Ω · m.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anisotropic conductive sheet having conductivity in a thickness direction.

[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.

Heretofore, as such anisotropic conductive elastomer sheets, those having various structures are known. For example, as an anisotropic conductive elastomer sheet showing conductivity in the absence of pressure, a sheet base made of insulating rubber, conductive fibers arranged in a state of being oriented to extend in the thickness direction, carbon Conductive rubber containing black or metal powder and insulating rubber alternately laminated along the surface direction (Japanese Patent Laid-Open No. 50-94495)
For example, are known. On the other hand, as an anisotropic conductive elastomer sheet which exhibits conductivity when pressed in the thickness direction, a sheet obtained by uniformly dispersing metal particles in an elastomer (see JP-A-51-93393), A plurality of conductive path forming portions extending in the thickness direction and an insulating portion for insulating these from each other are formed by distributing the non-uniform magnetic material particles in the elastomer (JP-A-53-147772). Japanese Patent Application Laid-Open No. 61-250906 discloses a structure in which a step is formed between the surface of a conductive path forming portion and an insulating portion.

[0005]

However, in the field of electronic parts or electronic parts applied equipment, in the field of no pressure or in the state of being pressed in the thickness direction with a small force,
A certain degree of conductivity in the thickness direction (for example, a volume resistivity of 1
× 10 ⁷ to 1 × 10 ¹² Ω · m), and in a state of being pressed in the thickness direction with a large force, a higher conductivity (for example, volume resistivity) than a state of no pressure or a state of being pressed with a small force Is 1 × 10 ⁻² to 1 × 10 ⁷ Ω · m), but such an anisotropic conductive elastomer sheet is not known until now.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to show conductivity in a state where no pressure is applied or in a state where a small force is applied in the thickness direction and to provide a large force. An object of the present invention is to provide an anisotropic conductive sheet that exhibits higher conductivity when pressed in the thickness direction with no pressure or when pressed in the thickness direction with a small force.

[0007]

The anisotropic conductive sheet of the present invention is made of a conductive elastomer and is characterized in that it has a protrusion on at least one surface.

In the anisotropic conductive sheet of the present invention,
The conductive elastomer is introduced into an insulating elastomer.
It is preferable that the conductivity imparting substance is dispersed.
This conductivity-imparting substance is a substance that itself exhibits conductivity.
And a substance that exhibits conductivity by absorbing moisture
At least one substance selected from
No. Further, the conductive elastomer has a volume specific resistance.
Anti 1 × 10⁷~ 1 × 10 ¹²Preferably Ω · m
No. Further, the anisotropic conductive sheet of the present invention has
It may have a correspondingly formed protrusion
No. In the anisotropic conductive sheet of the present invention,
Corresponds to the protrusion height of the protrusion formed on the surface or both sides
The sum of the protrusion heights of the protrusions formed as
5 to 50% of the thickness of the place where the protrusion is located
preferable.

[0009]

According to the anisotropic conductive sheet of the present invention, since the projecting portion is formed on at least one surface, the connected object is in contact with one surface of the anisotropic conductive sheet (no pressure applied) or In a state where the connected body is pressed in the thickness direction with a small force, the connected body does not contact a portion other than the protruding portion on one surface of the anisotropic conductive sheet. In the state where the conductive material is pressed in the thickness direction by a large force by the connected object, the protruding portion is largely compressed, and the connected object is anisotropically conductive sheet. Because it contacts a part other than the protruding part on one surface, the conductive property according to the contact area between the connected body and the protruding part and other parts is shown. Therefore,
In a state in which the connection object presses in the thickness direction with a large force, it exhibits higher conductivity than in a non-pressed state or a state in which pressure is applied in the thickness direction with a small force.

[0010]

Embodiments of the present invention will be described below in detail. FIG. 1 is an explanatory cross-sectional view showing a configuration of an example of the anisotropic conductive sheet of the present invention.
FIG. 2 is an explanatory sectional view showing a part of the anisotropic conductive sheet shown in FIG. 1 in an enlarged manner. The anisotropic conductive sheet 10 is made of a conductive elastomer, and has a plurality of columnar protrusions 11 protruding upward formed on the upper surface thereof. Each of these protrusions 11 has substantially the same protrusion height, and is arranged apart from each other, for example, according to the lattice point position.

As the conductive elastomer constituting the anisotropic conductive sheet of the present invention, an elastomer obtained by dispersing a conductivity-imparting substance in an insulating elastomer can be suitably used. As the insulating elastomer for constituting the conductive elastomer, a polymer substance having a crosslinked structure is preferable. Various materials can be used as the curable polymer substance forming material that can be used to obtain the crosslinked polymer substance, and specific examples thereof include polybutadiene rubber, natural rubber, polyisoprene rubber, and styrene- Conjugated diene rubbers such as butadiene copolymer rubber and acrylonitrile-butadiene copolymer rubber and hydrogenated products thereof, and block copolymers such as styrene-butadiene-diene block copolymer rubber and styrene-isoprene block copolymer Rubber and hydrogenated products thereof, chloroprene, urethane rubber, polyester rubber, epichlorohydrin rubber, silicone rubber, ethylene-propylene copolymer rubber, ethylene-propylene-
And diene copolymer rubber. In the above,
When the obtained anisotropic conductive sheet is required to have weather resistance, it is preferable to use a material other than the conjugated diene rubber, and in particular, it is preferable to use a silicone rubber from the viewpoint of moldability and electrical properties. .

[0012] 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 these, 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. The following are preferred.

On the other hand, 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 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.

In the present invention, an appropriate curing catalyst can be used to cure 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 the catalyst which can be used as a catalyst for the hydrosilylation reaction include chloroplatinic acid and salts thereof, a siloxane complex containing a platinum-unsaturated group, a complex of vinylsiloxane and platinum, and platinum and 1,3-divinyltetramethyldisiloxane. And a complex of triorganophosphine or phosphite with platinum, acetylacetate platinum chelate, and a complex of cyclic diene and platinum. The amount of the curing catalyst 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. 15 parts by weight.

As the conductivity-imparting substance for constituting the conductive elastomer, a substance exhibiting conductivity by itself (hereinafter, also referred to as "self-conductive substance"), a substance exhibiting conductivity by absorbing moisture. (Hereinafter, also referred to as “moisture-absorbing conductive substance”) and the like. These self-conductive substances and moisture-absorbing conductive substances can be used either alone or in combination.

As the self-conductive substance, generally, a substance exhibiting conductivity by free electrons in a metal bond, a substance in which charge transfer occurs due to movement of surplus electrons, and a substance in which charge transfer occurs due to movement of vacancies And an organic polymer substance having a π bond along the main chain and exhibiting conductivity by the interaction thereof, and a substance which causes charge transfer by the interaction of a group in a side chain. Specifically, nonmagnetic metals such as platinum, gold, silver, copper, aluminum, manganese, zinc, tin, lead, indium, molybdenum, niobium, tantalum, and chromium; and strong metals such as nickel, iron, cobalt, and alloys thereof. Magnetic metal or particles made of these ferromagnetic metals, the surfaces of which are plated with a conductive metal such as gold, silver, palladium or rhodium which is difficult to oxidize; ZrFe ₂ , FeBe ₂ , FeRh, M
nZn, Ni ₃ Mn, FeCo, FeNi, Ni ₂ F
e, MnPt ₃ , FePd, FePd ₃ , Fe ₃ Pt,
Plating of a conductive metal such as gold, silver, palladium and rhodium which is hardly oxidized on the surface of a ferromagnetic intermetallic compound such as FePt, CoPt, CoPt ₃ , Ni ₃ Pt, or particles made of these ferromagnetic intermetallic compounds. Chemical formula: M ¹ O · Fe ₂ O ₃ (where M ¹ is Mn, F
e, metals such as Ni, Cu, Zn, Mg, Co, and Li. ), A mixture thereof (for example, Mn-Zn ferrite, Ni-Zn ferrite, etc.), a manganite such as FeMn ₂ O ₄ , a chemical formula: M ² O · Co ₂ O ₃ (where M ² is , cobaltite represented by.) indicating Fe, a metal such as Ni, Ni _0.5
Zn _0.5 Fe ₂ O ₄ , Ni _0.35 Zn _0.65 Fe ₂ O ₄ , N
i _0.7 Zn _0.2 Fe _0.1 Fe ₂ O ₄ , Ni _0.5 Zn _0.4
A ferromagnetic metal oxide such as Fe _0.1 Fe ₂ O ₄ , or gold,
Plated with a conductive metal such as silver, palladium or rhodium which is difficult to oxidize; particles made of non-magnetic metal particles, glass beads, inorganic substances such as carbon, or polymers such as polystyrene or polystyrene cross-linked with divinylbenzene Particles made of a conductive magnetic material such as nickel or cobalt plated on the surface of the particles, or coated with both a conductive magnetic material and a conductive metal that is difficult to oxidize; copper dioxide, zinc oxide, tin oxide ,
Non-magnetic conductive metal oxides such as titanium oxide; whiskers,
Conductive fiber materials such as potassium titanate and carbon; semiconductive materials such as germanium, silicon, indium phosphorus, and zinc sulfide; carbon materials such as carbon black and graphite; polyacetylene polymers, polyphenylene polymers, and thiophenylene polymers Conductive high molecular substances such as heterocyclic polymers can be used.
Further, these self-conductive substances may have an insulating film formed on the surface for the purpose of adjusting the conductivity. Here, as the insulating film, an inorganic material such as a metal oxide or a silicon oxide compound, or an organic material such as a resin or a coupling agent can be used. Such self-conductive substances can be used alone or in combination of two or more.

As the moisture-absorbing conductive substance, a substance that generates ions and carries charges by the ions, a substance having a group having a large polarity such as a hydroxyl group or an ester group, or the like can be used. Specifically, cation-forming substances such as quaternary ammonium salts and amine compounds; aliphatic sulfonates, higher alcohol sulfates, higher alcohol ethylene oxide addition sulfates, higher alcohol phosphates, Substances which generate both anions such as higher alcohol ethylene oxide addition phosphoric acid ester salts; Substances which generate both cations and anions such as bedyne compounds; Silicon compounds such as chloropolysiloxane, alkoxysilane, alkoxypolysilane and alkoxypolysiloxane , Conductive urethane,
High molecular substances such as polyvinyl alcohol or a copolymer thereof, higher alcohols such as ethylene oxide, polyethylene glycol fatty acid esters and polyhydric alcohol fatty acid esters, and substances having large polar groups such as polysaccharides are used. be able to. Such a moisture-absorbing conductive substance can be used alone or in combination of two or more.

Further, among the above-mentioned moisture-absorbing conductive substances, they have high heat resistance and good compatibility with elastic polymer substances.
Aliphatic sulfonates are preferred in that they do not cause polymerization inhibition in the formation of the elastic polymeric material. Such aliphatic sulfonates include 1-decane sulfonate and 1-decane sulfonate.
Undecane sulfonate, 1-dodecane sulfonate,
1-tridecane sulfonate, 1-tetradecane sulfonate, 1-pentadecane sulfonate, 1-hexadecane sulfonate, 1-heptadecane sulfonate, 1
Those having an alkyl group having 5 to 20 carbon atoms, such as -octadecanesulfonic acid salt, 1-nonadecanesulfonic acid salt, 1-eicosandecasulfonic acid salt, and isomers thereof are preferable. Further, as the salt, an alkali metal salt such as lithium, sodium and potassium is preferable.
Sodium salts are preferred because they have higher heat resistance.

The proportion of the conductivity-imparting substance in the conductive elastomer is appropriately set in accordance with the type of the conductivity-imparting substance and the desired degree of conductivity. 1 to 10% by weight, preferably 2 to 8% by weight when used alone, and 10 to 40% by weight when used alone as a conductivity-imparting substance made of a conductive metal oxide; Preferably 20 to
30% by weight, 5 to 30% by weight, preferably 8 to 15% by weight, when using a substance made of a conductive fiber substance alone as a conductivity-imparting substance, a substance consisting of carbon black alone as a conductivity-imparting substance If used in
To 40% by weight, preferably 20 to 30% by weight, and when a substance made of a conductive polymer is used alone as the conductivity-imparting substance, 10 to 30% by weight, preferably 15 to 2% by weight.
5% by weight, 2 to 40% by weight, preferably 3 to 3% by weight when a moisture-absorbing conductive substance is used alone as the conductivity-imparting substance.
It is set from the range of 0% by weight. In the case where the above-mentioned various conductivity-imparting substances are used in combination, the ratio is set in consideration of the above range.

The conductive elastomer may contain an inorganic filler such as ordinary silica powder, colloidal silica, airgel silica, and alumina, if necessary. By including such an inorganic filler, the thixotropy of the material for forming the anisotropic conductive sheet is ensured, the viscosity thereof is increased, and the anisotropic conductive sheet 10 having high strength is obtained. Can be

The volume resistivity of such conductive elastomers is appropriately selected depending on the intended use and the required conductivity of the anisotropic conductive sheet, 1 × 10 ⁷ to 1
× 10 ¹² Ω · m, more preferably 1 × 10 ⁸ to 1 × 10 ¹¹ Ω · m, and particularly preferably 1 × 1 Ω · m.
0 ⁹ to 1 × 10 ¹⁰ Ω · m.

The diameter and the arrangement pitch of the protruding portions 11 are appropriately set according to the purpose of use of the anisotropic conductive sheet 10. The diameter of the protruding portion 11 is 0.02 to 2 mm, particularly 0.05 to 0.4 in that the contact portion is securely contacted with the connected body.
mm, and the arrangement pitch of the protrusions 11 is preferably 0.03 to 2.54 mm, particularly preferably 0.05 to 0.5 mm. The ratio of the area of the surface of the protrusion 11 to the surface of the anisotropic conductive sheet 10 is appropriately set according to the purpose of use of the anisotropic conductive sheet 10.
It is preferably from 01 to 15%, more preferably from 0.1 to 10%, particularly preferably from 0.5 to 5%.

The protruding height h of the protruding portion 11 is appropriately set according to the purpose of use of the anisotropic conductive sheet, and may be 5 to 50% of the thickness d at the position where the protruding portion 11 is located. It is preferably, more preferably, 10 to 40%, particularly preferably, 15 to 30%. If the protruding height h of the protruding portion 11 is too small, even when the protruding portion 11 is pressed with a small pressing force by the connected body, the connected body comes into contact with a portion other than the protruding portion 11, The desired electrical resistance value may not be obtained. On the other hand, when the protruding height of the protruding portion 11 is excessive, even if the protruding portion 11 is pressed with a considerably large pressing force by the connected body, the connected body does not contact a portion other than the protruding portion 11, and The desired conductivity may not be obtained. The thickness d of the anisotropic conductive sheet 10 at the position where the protrusion 11 is located is, for example, 0.02 to 2 mm, preferably 0.02 to 2 mm.
5 to 0.5 mm.

The degree of conductivity of the anisotropic conductive sheet 10 is as follows:
It is appropriately set according to the purpose of use of the anisotropic conductive sheet 10, and specifically, the connected object is the anisotropic conductive sheet 1.
0, i.e., in a state in which it is in contact with the surface of the protruding portion 11, that is, in a non-pressurized state, or with a small force such that the connected object does not contact the surface of the anisotropic conductive sheet 10 other than the protruding portion 11. In the pressed state,
The volume resistivity in the thickness direction of the anisotropic conductive sheet 10 (apparent value including the space between adjacent protrusions; hereinafter, referred to as “volume resistivity R ₀ ”) is 1 × 10 ⁷ -1.
It is preferably in the range of × 10 ¹² Ω · m, more preferably 1 × 10 ⁸ to 1 × 10 ¹¹ Ω · m, and particularly preferably 1 × 10 ⁹ to 1 × 10 ¹⁰ Ω · m. On the other hand, in a state in which the connected body contacts the surface other than the protruding portion 11 of the anisotropic conductive sheet 10 or is pressed by a force large enough to press the surface other than the protruding portion 11, Volume resistivity in the thickness direction of the anisotropic conductive sheet 10 (hereinafter, referred to as “volume resistivity R ₁ ”).
Is the ratio of the volume resistivity R ₀ to the volume resistivity R ₁ (R ₀
/ R ₁ ) is preferably in the range of 1 × 10 to 1 × 10 ^4, and more preferably the ratio (R ₀ / R ₁ ) is 2 × 1
0 to 1 × 10 ³ , particularly preferably the ratio (R ₀ /
R ₁ ) is in the range of 5 × 10 to 5 × 10 ² .

In the above, the volume resistivity in the thickness direction of the anisotropic conductive sheet can be measured as follows. Non-pressurized volume specific resistance: A metal film is formed on one surface of an anisotropic conductive sheet by a sputtering device, and the wiring connected to the insulation resistance meter is bonded to the surface of this metal film with a conductive adhesive. I do. Then, by pressing the other surface of the anisotropic conductive sheet with the measuring electrode having an electrode diameter of 50 mm connected to the insulation resistance meter, the surface of the measuring electrode is sufficiently provided on the other surface of the anisotropic conductive sheet. Then, the surface of the measurement electrode is brought into contact with the other surface of the anisotropic conductive sheet, that is, in a non-pressurized state. Then, in this state, a current having an appropriate voltage value or current value is supplied between the measurement electrode and the metal film, and after elapse of one minute, the volume resistivity in the thickness direction of the anisotropic conductive sheet is measured. Volume resistivity in the state of being pressed in the thickness direction: Anisotropic conductive sheet is connected to an insulation resistance meter, and the electrode diameter is 5
Placed between the 0 mm measuring electrode and the pressing electrode,
The anisotropic conductive sheet is pressed by the pressing electrode until a required strain rate is obtained, and in this state, the volume resistivity in the thickness direction of the anisotropic conductive sheet is measured.

The above-described anisotropic conductive sheet can be manufactured, for example, as follows. First, a sheet molding material is prepared by mixing a polymer substance forming material which becomes an insulating elastomer by curing treatment, and a conductivity-imparting substance, and this sheet molding material is applied to a molding surface with a desired anisotropic conductive material. By injecting into a mold having a recess formed corresponding to the protruding portion of the conductive sheet, a sheet molding material layer is formed in the mold, and the sheet molding material layer is subjected to a curing treatment, An anisotropic conductive sheet having the configuration shown in FIG. 1 is obtained. In the above, the curing treatment of the sheet molding material layer is appropriately selected depending on the material used, but is usually performed by a heat treatment. The specific heating temperature and heating time are appropriately set in consideration of the type of the material for the polymer substance constituting the sheet molding material layer and the like.

According to the anisotropic conductive sheet 10 having the above-described structure, since a large number of protrusions 11 are formed on the upper surface, the connected object comes into contact with the upper surface of the protrusions 11 of the anisotropic conductive sheet 10. In a state, that is, in a non-pressurized state or in a state where the upper surface of the anisotropic conductive sheet 10 is pressed in the thickness direction by a small force by the connected body, the connected body contacts only the surface of the protruding portion 11. , And does not contact other portions, and as a result, exhibits conductivity according to the contact area between the connected body and the protruding portion 11. On the other hand, in a state where the upper surface of the anisotropic conductive sheet 10 is pressed in the thickness direction by a large force by the connected object, the protruding portions 11 are greatly compressed, and the connected object is located on the upper surface of the anisotropic conductive sheet. It also comes into contact with a portion other than the protruding portion 11, and as a result, exhibits conductivity according to the contact area between the connected body and the protruding portion 11 and other portions. Therefore, in a state in which the connected body is pressed in the thickness direction with a large force, compared to a state in which no pressure is applied or a state in which the connected body is pressed in the thickness direction with a small force, the connected body is anisotropically conductive. Since the contact area with the conductive sheet 10 is increased, high conductivity is exhibited.

Such an anisotropic conductive sheet of the present invention comprises:
By contacting the upper surface with the connected object or pressing with a small force, static electricity on the surface of the connected object,
Capacitance, a microscopic surface distribution state of an electric quantity such as an ion quantity can be transferred and held on the surface of the anisotropic conductive sheet, and further, a connected object is placed on the upper surface of the anisotropic conductive sheet. By applying pressure with a large force, the microscopic surface distribution state of the transferred and held amount of electricity can be moved to the other surface of the anisotropic conductive sheet. Specifically, the anisotropic conductive sheet of the present invention is used for moving the measuring unit for measuring the capacitance distribution on the surface of the inspection object in a capacitance type electrical inspection apparatus such as a printed wiring board. It is useful as a sensor unit, and according to such an electrical inspection device, the capacitance distribution on the surface of the inspection object can be expressed as a two-dimensional image. Further, for example, converting an ion pattern image generated from a writing device such as a laser printer or an electrostatic pattern image of a roll portion of an electronic copying device into an electric pattern image via the anisotropic conductive sheet of the present invention. Can be. Further, according to the anisotropic conductive sheet of the present invention, the present invention is not limited to the above example, and may include static electricity, capacitance,
A microscopic surface distribution state of an electric quantity such as an ion quantity can be expressed as a two-dimensional electric pattern image.
In addition, the anisotropic conductive sheet of the present invention can be used in various applications in which the conventional anisotropic conductive sheet is used, for example, as a connector for achieving electrical connection between circuit devices, or as a circuit device. It can be used as a connector used for electrical inspection. In addition, the anisotropic conductive sheet of the present invention can be used as an electromagnetic radiation absorbing sheet, thereby reducing, for example, electromagnetic noise generated from electronic components and the like.

FIG. 3 is an explanatory cross-sectional view showing the structure of another example of the anisotropic conductive sheet of the present invention. FIG. 4 is an enlarged view of a part of the anisotropic conductive sheet shown in FIG. It is an explanatory sectional view shown. The anisotropic conductive sheet 20 is made of a conductive elastomer, and has on its upper and lower surfaces a plurality of column-shaped upper surface side protruding portions 21 and lower surfaces formed corresponding to each other and protruding upward and downward, respectively. A side protrusion 22 is formed. Specifically, on the upper surface of the anisotropic conductive sheet 20, for example, a number of upper surface-side protrusions 21 are formed separated from each other according to lattice points, and on the lower surface of the anisotropic conductive sheet 10, the upper surface-side protrusions are formed. A lower surface-side protrusion 22 is formed at a position directly below each of the upper surfaces 21. Each of the upper surface-side protrusions 21 has substantially the same height, and each of the lower surface-side protrusions 22 is substantially It has the same protrusion height. The material of the conductive elastomer forming the anisotropic conductive sheet 20 is the same as the conductive elastomer forming the anisotropic conductive sheet 10 described above.

In such an anisotropic conductive sheet 20, the sum of the projection height h1 of the upper projection 21 and the projection height h2 of the lower projection 22 is equal to the upper projection 21.
The thickness d is preferably 5 to 50% of the thickness d where the lower surface side protruding portion 22 is located, and more preferably 10 to 50%.
-40%, particularly preferably 15-30%. The protrusion height h1 of the upper surface side protrusion 21 and the protrusion height h2 of the lower surface side protrusion 22 may be the same or different.
When pressed in the thickness direction, the upper and lower projections 21 and 22 preferably have substantially the same amount of distortion in that they have the same amount of distortion. The diameter and arrangement pitch of each of the upper surface side protrusion 21 and the lower surface side protrusion 22, the ratio of the area of the upper surface side protrusion 21 and the lower surface side protrusion 22 to the surface of the anisotropic conductive sheet 20, the upper surface side protrusion 21
The thickness of the portion where the lower surface side protruding portion 22 is located and the degree of conductivity of the anisotropic conductive sheet 20 are determined by the diameter and arrangement pitch of the protruding portion 11 of the anisotropic conductive sheet 10 described above, the anisotropic conductive sheet The same applies to the ratio of the area of the projection 11 to the surface of the projection 10, the thickness of the portion where the projection 11 is located, and the degree of conductivity of the anisotropic conductive sheet 10.

According to the anisotropic conductive sheet 20 having the above-described structure, the upper surface and the lower surface are formed with a large number of upper surface side protrusions 21 and lower surface side protrusions 22, respectively. The upper or lower surface of the anisotropic conductive sheet 10 has a small force due to a state in which the connected body is in contact with each of the surface of the upper surface side protruding portion 21 and the surface of the lower surface side protruding portion 22, that is, in a non-pressurized state or due to the connected body. In the state where the pressure is applied in the thickness direction, the connected body contacts only the surfaces of the upper surface side protruding portion 21 and the lower surface side protruding portion 22 and does not contact other portions. It shows conductivity according to the contact area between the body and the upper surface side protrusion 21 and the lower surface side protrusion 22. On the other hand, in a state where the upper surface or the lower surface of the anisotropic conductive sheet 20 is pressed in the thickness direction by a large force by the connected body, the upper surface side protruding portion 21 and the lower surface side protruding portion 22 are greatly compressed, and The body also comes into contact with the upper and lower surfaces of the anisotropic conductive sheet 20 except for the upper and lower projecting portions 21 and 22, and as a result, the connected object and the upper and lower projecting portions 21 and 22 In addition, it shows conductivity according to the contact area with other places. Therefore, in a state in which the connected body is pressed in the thickness direction with a large force, compared to a state in which no pressure is applied or a state in which the connected body is pressed in the thickness direction with a small force, the connected body is anisotropically conductive. Since the contact area with the conductive sheet 20 is increased, high conductivity is exhibited.

FIG. 5 is an explanatory sectional view showing the structure of still another example of the anisotropic conductive sheet of the present invention.
FIG. 6 is an explanatory sectional view showing a part of the anisotropic conductive sheet shown in FIG. 5 in an enlarged manner. The anisotropic conductive sheet 30 is made of a conductive elastomer, and has a plurality of columnar first protrusions 31 protruding upward on the upper surface thereof.
The first projection 31 is provided on the upper surface of each of the projections 31.
, A columnar second projecting portion 32 projecting upward from the upper surface is formed. Each of the first protrusions 31 has substantially the same protrusion height, and each of the second protrusions 32 has substantially the same height. Further, the first protrusions 31 are arranged apart from each other according to, for example, a lattice position, and the second protrusion 32 is arranged at the center of the upper surface of the first protrusion 31. The material of the conductive elastomer forming the anisotropic conductive sheet 30 is the same as the conductive elastomer forming the anisotropic conductive sheet 10 described above.

In the anisotropic conductive sheet 30, the diameters and arrangement pitches of the first protrusions 31 and the second protrusions 32 are appropriately set according to the purpose of use of the anisotropic conductive sheet 30. The diameter of the first protrusion 31 is 0.1 to 1 m
m, particularly preferably 0.2 to 0.8 mm, and the diameter of the second protrusion 32 is 0.02 to 0.1 mm, especially 0.1 to 0.8 mm.
04 to 0.08 mm, and the arrangement pitch of the first projection 31 and the second projection 32 is 0.2 to 0.28 mm.
It is preferably 2.54 mm, particularly preferably 0.25 to 2 mm. The ratio of the area of the surface of the first protrusion 31 (not including the surface of the second protrusion 32) to the surface of the anisotropic conductive sheet 30 and the ratio of the surface of the second protrusion 32 are anisotropic. It is set as appropriate according to the purpose of use of the conductive sheet 30 and the like, but the first protrusion 31 is 1 to 10%, particularly 2 to 5%
It is preferable that the second protrusion 32 is 0.01 to
It is preferably 0.1%, particularly preferably 0.02 to 0.08%. The ratio of the area of the surface of the first projection 31 to the area of the surface of the second projection 32 is (the area of the surface of the first projection 31) / (the surface of the second projection 32). Area) is 1
It is preferably from × 10 ⁻⁴ to 4 × 10 ⁻² , particularly preferably from 4 × 10 ⁻⁴ to 1 × 10 ⁻² .

The protruding height h3 of the first protruding portion 31 and the protruding height h4 of the second protruding portion 32 are appropriately set in accordance with the purpose of use of the anisotropic conductive sheet 30. The total of the projection height h3 of the projection 31 and the projection height h4 of the second projection 32 is preferably 5 to 50% of the thickness d at the position where the second projection 32 is located, It is preferably from 10 to 40%, particularly preferably from 15 to 30%. The projection height h3 of the first projection 31 is preferably 3 to 40%, more preferably 5 to 30%, particularly preferably 5 to 30% of the thickness d where the second projection 32 is located. 7 to 25%, and the protrusion height h4 of the second protrusion 32 is 2% of the thickness d at the position where the second protrusion 32 is located.
-30%, more preferably 2.5%
-25%, particularly preferably 5-20%. The ratio (h3 / h4) of the projection height h3 of the first projection 31 to the projection height h4 of the second projection 32 is preferably 0.8 to 2, and more preferably 1 to 2. To 1.8, particularly preferably 1.2 to 1.5. In addition, the thickness d of the portion of the anisotropic conductive sheet 30 where the second protrusion 32 is located
Is, for example, 0.02 to 2 mm, preferably 0.05 to
0.5 mm.

The degree of conductivity of the anisotropic conductive sheet 30 is as follows.
It is set appropriately according to the purpose of use of the anisotropic conductive sheet 30. Specifically, the connected object is the anisotropic conductive sheet 30.
In a state in which it is in contact with the surface of the second protruding portion 32, that is, in a non-pressurized state, or to such an extent that the connected object does not contact the surface of the anisotropic conductive sheet 30 other than the second protruding portion 32 due to the connected object. (Hereinafter, referred to as a “low pressure state”), the volume resistivity of the anisotropic conductive sheet 30 in the thickness direction (the adjacent first protrusion and the second The apparent value including the space between the protrusions, hereinafter referred to as “volume resistivity R ₁₀ ”) is preferably in the range of 1 × 10 ⁷ to 1 × 10 ¹² Ω · m, more preferably 1 × 10 ⁷ Ω · m. 10 ⁸ -1 × 10 ¹¹
Ω · m, particularly preferably 1 × 10 ⁹ to 1 × 10 ¹⁰ Ω · m
It is. In addition, a force to such an extent that the connected body comes into contact with the surface of the first protrusion 31 of the anisotropic conductive sheet 30 by the connected body, or both the first protrusion 31 and the second protrusion 32 are applied. In a state where the pressure is applied and the pressure is applied with a force that does not make contact with other surfaces (hereinafter, referred to as “medium pressure state”), the volume specific resistance in the thickness direction of the anisotropic conductive sheet 30 (adjacent area) An apparent value including the space between the first protrusions, which will be referred to as a “volume resistivity R ₁₁ ” below.
That. ) Is preferably in a range where the ratio (R ₁₀ / R ₁₁ ) of the volume resistivity R ₁₀ to the volume resistivity R ₁₁ is 1 × 10 ⁻⁴ to 4 × 10 ^−2, and more preferably the ratio ( R ₁₀ / R
₁₁ ) is 4 × 10 ⁻⁴ to 1 × 10 ⁻² , particularly preferably, the ratio (R ₁₀ / R ₁₁ ) is 1 × 10 ^{−3 to} 5 × 10 ⁻² . Further, the connected body contacts the surface of the anisotropic conductive sheet 30 other than the first and second protrusions 31 and 32 or the first and second protrusions 31 and 32. In a state where the surface other than the surface 32 is pressed with a force enough to press the surface (hereinafter, referred to as a “highly pressed state”), the volume resistivity in the thickness direction of the anisotropic conductive sheet 30 (hereinafter, referred to as “volume”) resistivity R ₁₂ "
That. ) Is preferably in a range where the ratio (R ₁₁ / R ₁₂ ) of the volume resistivity R ₁₁ to the volume resistivity R ₁₂ is 1 × 10 ⁻² to 2 × 10 ^−1, and more preferably the ratio ( R ₁₁ / R
₁₂ ) is in the range of 2 × 10 ⁻² to 1 × 10 ⁻¹ , particularly preferably, the ratio (R ₁₁ / R ₁₂ ) is in the range of 4 × 10 ⁻² to 8 × 10 ⁻² .

According to the anisotropic conductive sheet 30 having the above-described structure, since the first protrusions 31 and the second protrusions 32 projecting from the upper surface are formed on the upper surface, the anisotropic conductive sheet 30 is formed. In a state where the connected object is in contact with the upper surface of the second protruding portion 32 of the sheet 30, that is, in a non-pressurized state or a low pressure state, the connected object is in contact with the second protruding portion 32.
And only the surface of the second projection 32 does not come into contact, and as a result, exhibits conductivity according to the contact area between the connected body and the second projection 32. In the medium pressurized state, the first
Also contact the upper surface of the projection 31 of the first projection 31, and as a result, exhibit conductivity according to the contact area between the connected body and the first projection 31 and the second projection 32. Accordingly, the contact area between the connected body and the anisotropic conductive sheet 10 is larger in the medium pressurized state than in the non-pressurized state or the low pressurized state, so that the conductive property is high. Furthermore, in the high pressure state, the upper surface other than the first protrusion 31 and the second protrusion 32 also comes into contact, and as a result, the connected body and the first protrusion 3
The first and second protruding portions 32 and the other portions have conductivity depending on the contact area with the other portions. Therefore, in the high pressure state, the contact area between the connected body and the anisotropic conductive sheet 10 is larger than in the medium pressure state, so that high conductivity is exhibited. Thus, according to the anisotropic conductive sheet 30 described above, the conductivity in the thickness direction can be changed stepwise by changing the pressurized state in the thickness direction.

[0038]

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

<Example 1> Addition type liquid silicone rubber 1
A sheet molding material was prepared by adding and mixing 30 parts by weight of a conductivity-imparting substance in 00 parts by weight. In the above, as the conductivity-imparting substance, 20 parts by weight of carbon black (self-conducting substance) manufactured by Denki Kagaku and nickel particles having a number average particle diameter of 3 μm (self-conducting substance)
10 parts by weight of the mixture were used.

On the molding surface, the diameter is 0.01 mm and the depth is 0.01 m in accordance with the lattice point position where the pitch is 0.04 mm.
m, a lower mold having a flat molding surface, and a thickness of 0.2 between the upper mold and the lower mold.
A mold comprising a mm-shaped frame-shaped spacer was prepared, and the prepared sheet molding material was injected into the cavity of the mold to form a sheet molding material layer. Subsequently, the sheet forming material layer was cured at 80 ° C. for 3 hours to produce an anisotropic conductive sheet having the configuration shown in FIG. This anisotropic conductive sheet has a protrusion diameter of 0.01 m.
m, the pitch is 0.04 mm, the ratio of the surface area of the protrusion to the surface is 4.9%, the thickness of the portion where the protrusion is located is 0.21 mm, and the protrusion height of the protrusion is 0.01 mm. The conductive elastomer constituting the anisotropic conductive sheet had a volume resistivity of 1 × 10 ⁷ Ω · m.

Example 2 Addition type liquid silicone rubber 1
A sheet molding material was prepared by adding and mixing 15 parts by weight of the conductivity-imparting substance to 00 parts by weight. In the above, sodium alkane sulfonate (moisture-absorbing conductive substance) having 5 to 15 carbon atoms in the alkyl group was used as the conductivity-imparting substance. An anisotropic conductive sheet having the configuration shown in FIG. 1 was manufactured in the same manner as in Example 1 except that this sheet molding material was used. In this anisotropic conductive sheet, the diameter of the protrusion is 0.01 mm, the pitch is 0.04 mm, the ratio of the surface area of the protrusion to the surface is 4.9%, and the thickness of the portion where the protrusion is located is 0%. .21 mm, the protrusion height of the protrusion is 0.01 mm, and the volume specific resistance of the conductive elastomer constituting the anisotropic conductive sheet is 4 × 10 ⁸ Ω.
M.

Example 3 Addition type liquid silicone rubber 1
A sheet molding material was prepared by adding and mixing 20 parts by weight of a conductivity-imparting substance in 00 parts by weight. In the above, as the conductivity-imparting substance, a mixture of 10 parts by weight of sodium alkane sulfonate (moisture-absorbing conductive substance) having 5 to 15 carbon atoms in the alkyl group and 10 parts by weight of zinc oxide powder (self-conductive substance) was used. .

Each molding surface has a pitch of 0.03 mm
The upper and lower dies, each of which has a number of recesses having a diameter of 0.01 mm and a depth of 0.01 mm corresponding to each other, are disposed between the upper and lower dies according to the lattice point positions. A mold including a frame-shaped spacer having a thickness of 0.15 mm was prepared, and the prepared sheet molding material was injected into the cavity of the mold to form a sheet molding material layer. Next, the sheet forming material layer was cured at 120 ° C. for 0.5 hour to produce an anisotropic conductive sheet having the configuration shown in FIG. This anisotropic conductive sheet is
The diameter of each of the upper surface side protrusion and the lower surface side protrusion is 0.0
1 mm, the pitch is 0.03 mm, respectively, the ratio of the surface area of the upper surface protruding portion and the lower surface side protruding portion to the surface is 8.7%, and the thickness of the portion where the upper surface protruding portion and the lower surface protruding portion are located is 0.17 mm, the protrusion height of the upper surface side protrusion and the lower surface side protrusion is 0.01 mm (0.02 mm in total) each, and the volume resistivity of the conductive elastomer constituting the anisotropic conductive sheet is 1 × 10 ⁹ Ω · m.

<Comparative Example 1> Example 1 was repeated except that an upper mold and a lower mold, each having a flat molding surface, and a frame-shaped spacer having a thickness of 0.2 mm were used as molds.
A sheet was produced in the same manner as described above.

Comparative Example 2 Addition type liquid silicone rubber 1
A sheet molding material was prepared by adding 100 parts by weight of the conductive particles to 00 parts by weight and mixing. Above, as the conductive particles, those obtained by partially coating the surface of nickel particles (number average particle diameter: 10 μm) with a silane coupling agent to reduce the conductivity were used. A mold composed of an upper mold and a lower mold each made of a 5 mm-thick iron plate and having a flat molding surface and a frame-shaped spacer having a thickness of 0.2 mm was prepared and prepared in the cavity of the mold. The sheet molding material was injected to form a sheet molding material layer. Next, electromagnets are arranged on the upper surface of the upper mold and the lower surface of the lower mold, and at 100 ° C. while applying a parallel magnetic field of 0.5 T to the sheet forming material layer in the thickness direction thereof.
A conventional anisotropic conductive sheet was manufactured by performing a curing treatment on the sheet molding material layer under the condition of 2 hours. The ratio of the conductive particles in the anisotropic conductive sheet was 10% by volume.

<Evaluation of Electric Properties of Sheet> Examples 1 to 3
And electrical characteristics of the sheets according to Comparative Examples 1 and 2,
The evaluation was performed as follows. [Volume Specific Resistance in Thickness Direction Under No Pressure] A metal film having a thickness of 100 nm was formed on one surface of the sheet by using an ion sputtering apparatus (E1010, manufactured by Hitachi Science) with Au-Pd as a target. A wiring connected to an insulation resistance meter (4339A high resistance meter, manufactured by HP) was bonded to the surface of the metal film with a conductive adhesive containing silver. Then, by pressing the other surface of the sheet with a measuring electrode having an electrode diameter of 50 mm connected to the insulation resistance meter, the surface of the measuring electrode is sufficiently adhered to the other surface of the sheet. The state where the surface of the measurement electrode was in contact with the other surface, that is, the state where no pressure was applied, was set. In this state, a current having an appropriate voltage value or current value is supplied between the measurement electrode and the metal film, and after one minute, the volume resistivity in the thickness direction of the sheet (both ends of the conductive path forming portion) Including the space formed above)
Was measured. [Volume specific resistance pressed in the thickness direction] Each sheet was connected to an insulation resistance meter (4339A high resistance meter, manufactured by HP) and the electrode diameter was 50 mm.
Is disposed between the measurement electrode and the pressure electrode, and the sheet is pressed by the pressure electrode until the strain rate becomes 30%.
In this state, the volume resistivity in the thickness direction of the sheet was measured. The results are shown in Table 1.

[0047]

[Table 1]

[Charge Transfer and Mobility] As shown in FIG. 7, a sheet 1 was placed on a ground plate 40, and a roll 45 made of urethane resin was placed immediately above the sheet 1. The roll 45 has a surface on which electric charge is accumulated by being subjected to a discharge treatment by a Tesla coil, and has a surface potential of 500 ± 50 V (measured by a surface electrometer “Model 520-1” manufactured by Trek Japan). Value). Then, the roll 45 is gradually lowered to make contact with the surface of the sheet 1 (in a non-pressurized state), and after maintaining this state for 1 minute, the roll 45 is gradually raised to reduce the surface potential of the sheet 1 by: It measured by the surface electrometer "model 520-1". Next, by gradually lowering the roll 45, the surface of the sheet 1 is pressurized so that its distortion rate becomes 30%. After maintaining for 1 minute in this state, the roll 45 is gradually raised, and the surface of the sheet 1 is gradually raised. The potential is measured using a surface electrometer “Model 520”.
-1 ". The above operation was performed ten times in total, and the average value of the surface potential and the variation in the value were obtained. The results are shown in Table 2 above.

[0049]

[Table 2]

As is clear from the results in Table 2, Examples 1 to
According to the anisotropically conductive sheet according to No. 3, by bringing the surface of the roll 45 into contact with the surface of the anisotropically conductive sheet, the charge on the surface of the roll 45 can be reproduced with high reproducibility on the surface of the anisotropically conductive sheet. Transfer was confirmed. Further, it was confirmed that when the surface of the anisotropic conductive sheet was pressed by the roll 45, the charge on the surface of the roll 45 moved to the ground plate via the anisotropic conductive sheet. In contrast, in the sheet according to Comparative Example 1, the roll 45
, The charge on the surface of the roll 45 moved to the ground plate via the sheet, and could not be transferred and held on the surface of the sheet. Also,
In the anisotropic conductive sheet according to Comparative Example 2, the charge on the surface of the roll 45 could not be stably transferred to the surface.

[0051]

As described above, according to the present invention,
In a state where no pressure is applied or a state where pressure is applied in the thickness direction with a small force, conductivity is exhibited, and in a state where pressure is applied in the thickness direction with a large force, a state where no pressure is applied or a state where pressure is applied in the thickness direction with a small force An anisotropic conductive sheet showing higher conductivity can be provided.

[Brief description of the drawings]

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

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

FIG. 3 is an explanatory cross-sectional view illustrating a configuration of another example of the anisotropic conductive sheet of the present invention.

FIG. 4 is an explanatory sectional view showing a part of the anisotropic conductive sheet shown in FIG. 3 in an enlarged manner.

FIG. 5 is an explanatory sectional view showing a configuration of still another example of the anisotropic conductive sheet of the present invention.

6 is an explanatory sectional view showing a part of the anisotropic conductive sheet shown in FIG. 5 in an enlarged manner.

FIG. 7 is an explanatory view showing an apparatus used for evaluating electric characteristics of an anisotropic conductive sheet in Examples.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 sheet 10 anisotropic conductive sheet 11 projecting portion 20 anisotropic conductive sheet 21 upper surface side projecting portion 22 lower surface side projecting portion 30 anisotropic conductive sheet 31 first projecting portion 32 second projecting portion 40 ground plate 45 roll

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Ryoji Setaka F-term (reference) 2J011 AB06 AB08 AC14 AF04 4F071 AA11 AA12 AA13 AB03 AB06 AB08 AB12 AB18 AB20 AB32 AC12 AE15 AF37 BC01 BC08 5G307 HA02 HB01 HB02 HB03 HB05 HC02

Claims (6)

[Claims] 1. An anisotropic conductive sheet comprising a conductive elastomer and having a projection on at least one surface. 2. The anisotropically conductive sheet according to claim 1, wherein the conductive elastomer is obtained by dispersing a conductivity-imparting substance in an insulating elastomer. 3. The substance according to claim 2, wherein the conductivity-imparting substance is at least one substance selected from a substance exhibiting conductivity by itself and a substance exhibiting conductivity by absorbing moisture. Anisotropic conductive sheet. 4. The anisotropic conductive material according to claim 1, wherein the conductive elastomer has a volume resistivity of 1 × 10 ⁷ to 1 × 10 ¹² Ω · m. Sheet. 5. The anisotropically conductive sheet according to claim 1, further comprising projections formed on both sides thereof so as to correspond to each other. 6. The total height of the projecting portions of the projecting portions formed on one surface or the projecting portions of the projecting portions formed on both surfaces corresponding to each other is 5 to 5 times the thickness of the portion where the projecting portion is located.
The anisotropic conductive sheet according to any one of claims 1 to 5, wherein the content is 50%.