JP2001246626A - Mold and method for manufacturing anisotropic conductive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold capable of molding an anisotropic conductive sheet wherein a conductive part is filled with a required amount of conductive particles and conductive particles are not present in an insulating part or present therein in an extremely small amount and a method for manufacturing the anisotropic conductive sheet. SOLUTION: The mold is equipped with upper and lower molds and a molding space is formed between the upper and lower molds. A plurality of high magnetic field forming parts forming magnetic fields high in magnetic flux density in the thickness direction of the molding space, a medium magnetic field forming part provided around the high magnetic field forming parts and forming a magnetic field of which the magnetic flux density is lower than that of the high magnetic field forming parts in the thickness direction of the molding space and the low magnetic field forming part provided around the medium magnetic field forming part and forming a magnetic field of which the magnetic flux density is lower than that of the medium magnetic field forming part in the thickness direction of the molding space are provided to at least one of the upper and lower molds so as to be spaced apart from each other in the surface direction thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anisotropic connector suitable for use in electrical connection between circuit devices such as electronic components and for electrical inspection of circuit devices such as printed circuit boards and semiconductor integrated circuits. The present invention relates to a mold preferably used for forming a conductive sheet and a method for producing an anisotropic conductive sheet.

[0002]

2. Description of the Related Art An anisotropic conductive sheet is a sheet having conductivity only in a thickness direction or a pressurized conductive portion having conductivity only in the thickness direction when pressed in the thickness direction. Yes, compact electrical connection can be achieved without using means such as soldering or mechanical fitting, and soft connection is possible by absorbing mechanical shock and strain Utilizing such features, circuit devices such as printed circuit boards and leadless chip carriers, liquid crystal panels, etc., in the fields of electronic calculators, electronic digital watches, electronic cameras, computer keyboards, etc. It is widely used as a connector for achieving an electrical connection between the two.

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 sheet is interposed between the test electrode region of the circuit device and the test electrode region of the test circuit board. .

Conventionally, as such an anisotropic conductive sheet, those having various structures are known.
Patent Document 1-93393 discloses an anisotropic conductive sheet obtained by uniformly dispersing metal particles in an elastomer (hereinafter, referred to as an anisotropic conductive sheet).
This is called a “dispersed anisotropic conductive sheet”. JP-A-53-147772 discloses that a large number of conductive portions extending in the thickness direction are formed by distributing conductive magnetic particles unevenly in an elastomer. An anisotropic conductive sheet formed with an insulating portion to be insulated (hereinafter referred to as an “eccentrically-distributed anisotropic conductive sheet”) is disclosed. Further, JP-A-61-250906 discloses a sheet. An unevenly distributed anisotropic conductive sheet in which a step is formed between a surface of a conductive portion and an insulating portion is disclosed. Then, since the unevenly distributed anisotropic conductive sheet has a conductive portion formed in accordance with the pattern opposite to the electrode pattern of the circuit device to be connected, it should be connected compared to the dispersed type anisotropic conductive elastomer sheet. This is advantageous in that electrical connection between the electrodes can be achieved with high reliability even in a circuit device in which the electrodes are arranged at a small pitch.

[0005] As a method of manufacturing the above-described unevenly distributed anisotropic conductive sheet, a special anisotropic conductive sheet molding die is used, and a molding space of the anisotropic conductive sheet molding die is provided. Forming a sheet molding material layer in which conductive particles exhibiting magnetism are contained in a polymer substance material that is cured to become an elastic polymer substance, and the strength distribution in the thickness direction with respect to the sheet molding material layer is formed. A magnetic field having the following properties, the conductive particles are moved by the action of the magnetic force, and are aggregated in a portion to be a conductive part, and further the conductive particles are oriented so as to be aligned in the thickness direction. A method for curing is known.

[0006] The anisotropic conductive sheet molding die used in the above-described method for producing an anisotropic conductive sheet is formed of an upper plate and a lower die, each of which has a substantially flat plate shape and corresponds to each other. The upper mold and the lower mold are configured to be attachable to the electromagnet, or are configured integrally with the electromagnet, so that the sheet molding material layer can be heated and cured while applying a magnetic field to the sheet molding material layer. It is. Further, in order to form a conductive portion at an appropriate position by applying a magnetic field to the sheet molding material layer, one or both of the upper mold and the lower mold in the anisotropic conductive sheet molding mold is made of iron, nickel, or the like. On a substrate made of a ferromagnetic material such as iron, a ferromagnetic material portion made of iron, nickel, etc. for forming a high-intensity magnetic field in a molding space of a mold, and made of a nonmagnetic metal such as copper or a resin, etc. It has a configuration having a layer in which nonmagnetic portions are arranged in a mosaic pattern (hereinafter, referred to as a “mosaic layer”), and the molding surfaces of the upper mold and the lower mold are flat or anisotropic to be formed. The sheet has slight irregularities corresponding to the conductive portions of the conductive sheet.

According to the above-described mold for forming an anisotropic conductive sheet, by operating the electromagnet, the non-magnetic region is located in the region where the ferromagnetic portion is located in the molding space between the upper and lower dies. A magnetic field having a higher magnetic flux density than the region where the magnetic material portion is located is formed, so that a magnetic field having an intensity distribution can act on the sheet molding material layer formed in the molding space. In such an anisotropic conductive sheet forming mold, the arrangement, shape, and the like of the ferromagnetic material portion and the nonmagnetic material portion in the mosaic layer are determined based on the anisotropic conductive sheet to be formed. You. That is, a portion made of a ferromagnetic material is arranged at a portion corresponding to the conductive portion of the anisotropic conductive sheet, and the shape of the portion made of the ferromagnetic material matches the cross-sectional shape of the conductive portion.

[0008] However, it has been found that the following problems exist in the conventional anisotropic conductive sheet molding die. For example, QFP (Quad Flat Pack)
(Age) and other electronic components such as a wafer having a plurality of integrated circuits formed thereon in which electrodes are arranged in a frame shape along four sides of a rectangle. And a region where no electrode is disposed (hereinafter referred to as a “non-electrode disposed region”). When performing an electrical inspection of such an electronic component, a region where a conductive portion is arranged according to a pattern corresponding to an electrode pattern of an electrode arrangement region in the electronic component (hereinafter referred to as a “functional region”) is used as an anisotropic conductive sheet. ), And a region (hereinafter, also referred to as a “non-functional region”) formed corresponding to the non-electrode arrangement region and having no conductive portion at all. However, in the production of such an anisotropic conductive sheet, it is necessary to move the conductive particles present in a portion to be a non-functional region in the sheet molding material layer to a portion to be a conductive portion. In the case where the area of the non-functional region of the anisotropic conductive sheet is considerably large, the moving distance of the conductive particles existing in the portion to be the non-functional region becomes extremely long, so that the sheet molding is performed. Even when a magnetic field having an intensity distribution is applied to the material layer, it is difficult to surely assemble the conductive particles at a portion to be a conductive portion. As a result, the conductive portion to be formed is not filled with a required amount of conductive particles, so that high conductivity cannot be obtained.Moreover, a considerable amount of conductive particles remain in the non-functional region. However, it is difficult to reliably achieve the desired insulation in the non-functional region.

[0009]

SUMMARY OF THE INVENTION The present invention has been made under the above circumstances, and a first object of the present invention is to fill a conductive portion with a required amount of conductive particles, and It is another object of the present invention to provide a mold capable of forming an anisotropic conductive sheet having no or very few conductive particles existing in an insulating portion. A second object of the present invention is to reliably produce an anisotropic conductive sheet in which a conductive portion is filled with a required amount of conductive particles and has no or very few conductive particles present in an insulating portion. It is to provide a method that can be performed.

[0010]

SUMMARY OF THE INVENTION A mold according to the present invention comprises an upper mold and a lower mold to be paired with the upper mold, wherein a molding space is formed between the upper mold and the lower mold. Wherein at least one of the upper mold and the lower mold is provided with a plurality of high magnetic field forming portions that are provided apart from each other along the surface direction and form a magnetic field having a high magnetic flux density in the thickness direction of the molding space. And a medium magnetic field forming section provided around the high magnetic field forming section, for forming a magnetic field having a lower magnetic flux density than the high magnetic field forming section in the thickness direction of the molding space, and provided around the medium magnetic field forming section. And a low magnetic field forming section for forming a magnetic field having a lower magnetic flux density than the medium magnetic field forming section in the thickness direction of the molding space.

The mold of the present invention can be preferably used as a mold for forming an anisotropic conductive sheet. In the mold of the present invention, it is preferable that a cross-sectional area in a plane direction in the medium magnetic field forming section is 1.2 to 30 times a cross-sectional area in a plane direction in the high magnetic field forming section. Further, in the mold of the present invention, a magnetic substrate, and a second portion provided on the portion of the magnetic substrate where the high magnetic field forming portion and the medium magnetic field forming portion are located so as to protrude from the surface of the magnetic substrate. A first protruding magnetic body portion and a second protruding magnetic body provided at a portion of the first protruding magnetic body portion where the high magnetic field forming portion is located so as to protrude from a surface of the first protruding magnetic body portion. It is preferable to include a part.

[0012] The method for producing an anisotropic conductive sheet of the present invention comprises:
Multiple conductive parts extending in the thickness direction are mutually connected by insulating parts.
Manufactures an anisotropic conductive sheet placed in an insulated state
Is a method of manufacturing, which is cured into an elastic polymer material
Conductive particles exhibiting magnetism are contained in the elastic polymer material
Magnetic field with intensity distribution
In the thickness direction of the molding material, and
A step of curing the sheet molding material layer.
A part where a conductive part of the sheet molding material layer is to be formed.
The magnetic flux density in minutes_HThe part where the conductive part is to be formed
The magnetic flux density around the _M, Shape the conductive part
Magnetism in the part other than the part to be formed and its surroundings
Bundle density B_LAnd B_H> B_M> B_LSatisfy
It is characterized by the following.

[0013] The method for producing an anisotropic conductive sheet of the present invention.
The magnetic flux density B_MIs the magnetic flux density B _H30-90% of
And the magnetic flux density B_LIs the magnetic flux density B
_MIs preferably 80% or less. In addition, the present invention
In the method of manufacturing an anisotropic conductive sheet, the above mold is used.
To form a sheet molding material layer in this mold,
The magnetic material having strength distribution on the sheet molding material layer through the mold.
Preferably, a field is applied.

[0014]

According to the above-described mold, since the low magnetic field forming section is provided around the high magnetic field forming section via the medium magnetic field forming section, the conductive particles formed in the molding space are not provided. In the dispersed sheet forming material layer, the conductive particles present in the portion of the sheet forming material layer located on the low magnetic field forming portion are located on the medium magnetic field forming portion where a magnetic field having a higher magnetic flux density acts than the portion. It moves to a part located, and after that, it moves to a part located on a high magnetic field formation part where a magnetic field with a higher magnetic flux density acts than the part concerned. Therefore, even if the moving distance to the part located on the high magnetic field forming part is considerably long, the conductive particles can be surely aggregated in the part.

[0015]

Embodiments of the present invention will be described below in detail. <Mold> FIG. 1 is an explanatory cross-sectional view showing a configuration of a main part of a lower mold in an example of a mold for forming an anisotropic conductive sheet according to the present invention. This mold for forming an anisotropic conductive sheet is composed of a lower mold shown in FIG. 1 and an upper mold that is paired with the lower mold, and the upper mold and the lower mold are arranged so as to oppose each other. And a molding space is formed between the lower molds.

In the lower mold shown in FIG. 1, a plurality of high magnetic field forming portions H for forming a magnetic field having a high magnetic flux density in a thickness direction of a molding space formed between the lower mold and the upper mold are provided. Are provided apart from each other along the surface direction of the. The pattern of the high magnetic field forming portion H is a pattern corresponding to the pattern of the conductive portion of the anisotropic conductive sheet to be formed. Around each of the high magnetic field forming sections H, there is provided a medium magnetic field forming section M for forming a magnetic field having a lower magnetic flux density than the high magnetic field forming section H in the thickness direction of the molding space. That is, a low magnetic field forming part L that forms a magnetic field having a lower magnetic flux density than the medium magnetic field forming part M in the thickness direction of the molding space is provided at a portion other than the high magnetic field forming part H and the medium magnetic field forming part M.

More specifically, the lower die has a magnetic substrate 10, and a portion of the magnetic substrate 10 where the high magnetic field forming section H and the medium magnetic field forming section M are located is provided with the magnetic substrate 10. First protruding magnetic body portion 1 protruding from the surface of
5 is formed, and a plurality of second protruding magnetic body portions protruding from the surface of the first protruding magnetic body portion 15 are provided in a portion of the first protruding magnetic body portion 15 where the high magnetic field forming portion H is located. 20 are formed according to the pattern corresponding to the pattern of the conductive portion of the anisotropic conductive sheet to be formed. A nonmagnetic layer 30 is formed on the surface of the magnetic substrate 10 and the surface of the first protruding magnetic body portion 15, and the surface of the nonmagnetic layer 30 is formed on the second protruding magnetic body portion 20. Are substantially coplanar with the surface of. The mold for forming an anisotropic conductive sheet in this example is for forming an anisotropic conductive sheet having a conductive part protruding from the surface of the insulating part. Further, a cavity forming layer 35 having a hole 36 at a position located on the second protruding magnetic body portion 20 is integrally formed. The hole 36 in the cavity forming layer 35 is for forming a conductive part protruding from the surface of the insulating part.

Magnetic substrate 10, first protruding magnetic portion 15
As the magnetic material constituting the second protruding magnetic body portion 20, a ferromagnetic material such as iron, nickel, cobalt, or an alloy thereof can be used. Magnetic substrate 10,
First protruding magnetic body 15 and second protruding magnetic body 20
Are made of the same magnetic material,
It may be made of a different magnetic material. Also,
The magnetic substrate 10, the first protruding magnetic body 15, and the second protruding magnetic body 20 may be integrated or separate.

The thickness D of the magnetic substrate 10 is preferably 0.05 to 500 mm, more preferably 0.2 to 200 mm.
mm. The protrusion height h1 of the first protrusion magnetic body 15 and the protrusion height h2 of the second protrusion magnetic body 20 are:
It is appropriately designed in consideration of the dimensions and the arrangement pitch of the conductive parts of the anisotropic conductive sheet to be formed. The protrusion height h1 of the first protruding magnetic body part 15 is preferably 50 μm or more, more preferably 150 μm. Above, more preferably 250μ
m or more, more preferably 350 μm or more, and the protrusion height h2 of the second protrusion magnetic body 20 is preferably 0.0
1 to 0.5 mm, more preferably 0.02 to 0.2 mm
It is.

In the above description, when the protrusion height h1 of the first protruding magnetic body portion 15 is too small, the magnetic flux density of the magnetic field by the medium magnetic field forming portion M is smaller than the magnetic flux density of the magnetic field by the low magnetic field forming portion L. Is not sufficiently high, and therefore, in the sheet molding material layer formed in the molding space, the conductive particles present in the portion located on the low magnetic field forming portion are removed from the portion located on the medium magnetic field forming portion. It may be difficult to reliably move it. The second protruding magnetic body 20
If the protrusion height h2 is too small, the high magnetic field forming portion M
Is not sufficiently higher than the magnetic flux density of the magnetic field generated by the middle magnetic field forming unit M. Therefore, in the sheet forming material layer formed in the forming space, the magnetic flux density is located on the medium magnetic field forming unit. The conductive particles present in the part,
It may be difficult to reliably move to a portion located on the high magnetic field forming portion. On the other hand, the second protruding magnetic body 2
When the protrusion height h2 of 0 is excessive, the magnetic flux density of the magnetic field by the middle magnetic field forming unit M becomes relatively low, so that in the sheet forming material layer formed in the forming space,
In some cases, it may be difficult to reliably move the conductive particles present in the portion located on the low magnetic field forming portion to the portion located on the medium magnetic field forming portion.

The ratio (h1 / h2) of the protrusion height h1 of the first protrusion magnetic member 15 to the protrusion height h2 of the second protrusion magnetic member 20 is 0.1 to 5. Is preferred,
More preferably, it is 0.2 to 3. This ratio (h1 / h
If 2) is too small, the magnetic flux density of the magnetic field generated by the medium magnetic field forming unit M is relatively low, so that the sheet forming material layer formed in the forming space is positioned above the low magnetic field forming unit. In some cases, it may be difficult to reliably move the conductive particles present in the portion where the magnetic field is formed to the portion located on the medium magnetic field forming portion. On the other hand, when this ratio (h1 / h2) is excessive, the magnetic flux density of the magnetic field by the high magnetic field forming unit M is not sufficiently higher than the magnetic flux density of the magnetic field by the medium magnetic field forming unit M, and therefore, In the sheet molding material layer formed in the molding space, it is difficult to reliably move the conductive particles present in the portion located on the medium magnetic field forming portion to the portion located on the high magnetic field forming portion. Sometimes.

The material constituting the non-magnetic layer 30 is as follows.
It is preferable to use a cured resin material in that the nonmagnetic layer 30 can be easily formed. Specific examples of such a resin material include an acrylic resin, an epoxy resin, and polyimide.

The material forming the cavity forming layer 35 is as follows:
A resin material cured by radiation is preferable because the cavity forming layer 35 having the holes 36 can be formed with high dimensional accuracy by a photolithography technique. As the radiation-sensitive resin material for forming the cavity forming layer 35, a photoresist such as an acrylic dry film resist, an epoxy liquid resist, or a polyimide liquid resist can be used. The thickness of the cavity forming layer 35 is designed according to the protruding height of the conductive portion in the anisotropic conductive sheet to be formed, but is preferably 5 to 200 μm, more preferably 10 to 100 μm.

In the mold of the present invention, the medium magnetic field forming portion M
Is preferably 1.2 to 30 times the cross-sectional area in the plane direction in the high magnetic field forming portion L,
More preferably, it is 2 to 20 times. When the cross-sectional area in the plane direction in the middle magnetic field forming section M is too small, the cross-sectional area in the plane direction in the low magnetic field forming section L becomes relatively large. In some cases, it may be difficult to reliably move the conductive particles present in the located portion to the portion located on the medium magnetic field forming portion M. On the other hand, when the cross-sectional area in the plane direction in the middle magnetic field forming section M is excessively large, the distance between the periphery of the middle magnetic field forming section M and the periphery of the high magnetic field forming section H becomes considerably long. In some cases, it may be difficult to move the conductive particles existing near the periphery of the middle magnetic field forming portion M to a portion located on the high magnetic field forming portion M.

The above-mentioned mold for forming an anisotropic conductive sheet can be manufactured, for example, by the following first method or second method. [First Method] In this first method, first, FIG.
As shown in (1), a plate-like body 11 made of a magnetic material is prepared.
The thickness D1 of the plate-like body 11 is determined by the thickness D of the magnetic substrate 10 in the mold to be manufactured, the height h1 of the first protruding magnetic member 15, and the protrusion H2 of the second protruding magnetic member 20. Height h
It is equivalent to the sum of 2. Then, as shown in FIG. 3, the plate-like body 11 is formed by photolithography.
A resist layer 21 is formed on one surface according to a pattern corresponding to the pattern of the second protruding magnetic body portion 20 to be formed, and an etching process is performed on one surface of the plate-shaped body 11 to thereby obtain a structure shown in FIG. Thus, the second protruding magnetic body portion 20 having the protruding height h2 is formed. Then the second
Then, the resist layer 21 is removed from the surface of the protruding magnetic body portion 20, and then, as shown in FIG. 5, the surface of the second protruding magnetic body portion 20 on the plate-like body 11 and its peripheral portion are formed by photolithography. On the surface of the resist layer 22
Is formed, and a portion other than the portion where the resist layer 22 is formed is etched to form a first protruding magnetic body portion 15 having a protruding height h1 as shown in FIG. The magnetic substrate 10 having a thickness D is formed.

Next, the resist layer 22 is removed from the surface of the first protruding magnetic member 15 and the surface of the second protruding magnetic member 20.
Then, a thermosetting resin material layer is formed on the surface of the magnetic substrate 10 and the surface of the first protruding magnetic body portion 15, and the thermosetting resin material layer is subjected to a hardening treatment. As shown in FIG. 7, the nonmagnetic layer 30 is formed.
Thereafter, as shown in FIG. 8, a photoresist layer 37 is formed on the surface of the nonmagnetic layer 30 and the surface of the second protruding magnetic portion 20, and the second protruding magnetic layer is formed on the photoresist layer 37. A mask in which a radiation shielding portion is formed according to a pattern corresponding to the body portion 20 is arranged, and thereafter, a radiation irradiation process and a development process are performed on the photoresist layer 37 to form a cavity forming layer. 1
Is manufactured. Then, the upper mold is manufactured by basically the same method as the above-described method of manufacturing the lower mold, thereby manufacturing the desired anisotropic conductive sheet molding die.

[Second Method] In this second method, first, as shown in FIG.
Prepare 2 The thickness D2 of the plate-like body 12 is equal to the sum of the thickness D of the magnetic substrate 10 in the mold to be manufactured and the protrusion height h1 of the first protruding magnetic body portion 15. Then, as shown in FIG. 10, the first surface to be formed is formed on one surface of the plate-shaped body 12 by photolithography.
The resist layer 23 is formed in accordance with a pattern corresponding to the pattern of the protruding magnetic body portion 15 of FIG. Certain first protruding magnetic body 15
Is formed, and the magnetic substrate 10 having the thickness D is formed.

Next, the resist layer 23 is removed from the surface of the first protruding magnetic body portion 15, and thereafter, a thermosetting resin material layer is formed on the surface of the magnetic substrate 10, and the thermosetting resin material layer is formed. By performing the curing treatment, the nonmagnetic base layer portion 31 is formed as shown in FIG. Further, FIG.
As shown in the figure, the surface of the nonmagnetic base layer portion 31 and the second
A photoresist layer 32A is formed on the surface of
Is formed, and a mask on which a radiation shielding portion is formed in accordance with a pattern corresponding to the second protruding magnetic body portion 20 to be formed is arranged on the photoresist layer 32A. By performing the irradiation process and the development process, as shown in FIG. 14, the nonmagnetic upper layer portion 32 in which the holes 33 are formed according to the pattern corresponding to the second protruding magnetic body portion 20 to be formed is formed. Thus, the nonmagnetic layer 30 including the nonmagnetic base layer portion 31 and the nonmagnetic upper layer portion 32 is formed. here,
The thickness of the nonmagnetic upper layer portion 32 is equal to the protrusion height h2 of the second protrusion magnetic member 20 to be formed. Then, a portion of the first protruding magnetic body portion 15 exposed from the through hole 33 of the nonmagnetic upper layer portion 32 is subjected to electrolytic plating of a ferromagnetic metal to thereby form the inside of the through hole 33 of the nonmagnetic upper layer portion 32. As shown in FIG. 15, a second protruding magnetic body portion 20 protruding from the surface of the first protruding magnetic body portion 15 is formed by depositing a magnetic metal on the first magnetic material.

Thereafter, in the same manner as in the first method described above,
A photoresist layer is formed on the surface of the non-magnetic layer 30 and the surface of the second protruding magnetic body section 20, and a radiation shielding section is formed on the photoresist layer according to a pattern corresponding to the second protruding magnetic body section 20. Is disposed, and then the photoresist layer is irradiated with radiation and developed to form a cavity forming layer. Thus, the lower mold shown in FIG. 1 is manufactured. And
The upper mold is manufactured by a method basically similar to the method of manufacturing the lower mold described above, whereby the intended anisotropic conductive sheet molding die is manufactured.

According to the above-described mold, since the low magnetic field forming portion L is provided around the high magnetic field forming portion H via the medium magnetic field forming portion M, the conductive field formed in the molding space is formed. In the sheet molding material layer in which the conductive particles are dispersed, the conductive particles present in the portion of the sheet molding material layer located on the low magnetic field forming portion L are a medium magnetic field in which a magnetic field having a higher magnetic flux density acts than the portion. The part moves to a part located on the formation part M, and then moves to a part located on the high magnetic field formation part H on which a magnetic field having a higher magnetic flux density acts, that is, a part where a conductive part is to be formed. Therefore, the conductive particles present at a location where the distance to the portion located on the high magnetic field forming portion is considerably long can be reliably moved to the portion located on the high magnetic field forming portion, and the non-functional region Even if the area is large, the conductive portion is filled with a required amount of conductive particles, and the anisotropic conductive sheet having no or very few conductive particles present in the insulating portion can be formed. .

<Method of Manufacturing Anisotropic Conductive Sheet> In the method of manufacturing an anisotropic conductive sheet according to the present invention, first, a conductive material exhibiting magnetism in a material for a polymer material which is cured to be an elastic polymer material. By preparing a sheet molding material in which particles are dispersed and filling this molding material into a molding space of an anisotropic conductive sheet molding die shown in FIG. 1, for example, as shown in FIG. A sheet molding material layer 1A is formed in a molding space of a mold for molding a conductive sheet.

Various materials can be used as the curable polymer material used for preparing the sheet molding material. Specific examples thereof include polybutadiene rubber, natural rubber, polyisoprene rubber, and styrene-butadiene. Conjugated diene rubbers such as copolymer rubber, acrylonitrile-butadiene copolymer rubber, and hydrogenated products thereof;
Styrene-butadiene-diene block copolymer rubber,
Block copolymer rubbers such as styrene-isoprene block copolymers and hydrogenated products thereof, chloroprene, urethane rubber, polyester rubber, epichlorohydrin rubber, silicone rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer And polymer rubber. In the above, when weather resistance is required for the obtained anisotropic conductive sheet, it is preferable to use a material other than the conjugated diene rubber, and particularly, from the viewpoint of moldability and electrical characteristics, use of silicone rubber Is preferred.

As the silicone rubber, those obtained by crosslinking or condensing a liquid silicone rubber are preferable. 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 anisotropic conductive sheet, the molecular weight distribution index (refers to 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 preferably 2.0 or less.

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

Examples of the conductive particles used for preparing the sheet molding material include particles of magnetic metals such as nickel, iron, and cobalt, particles of alloys thereof, particles containing these metals, and particles of these metals. The core particles are obtained by plating the surface of the core particles 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. Particles, such as those obtained by plating the surface of the core particles with a conductive magnetic material such as nickel or cobalt, or those in which the core particles are coated with both a conductive magnetic material and a metal having good conductivity. No. In these, nickel particles are used as core particles,
It is preferable to use a material whose surface is plated with a metal having good conductivity such as gold or silver. 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%. Further, the coating amount of the conductive metal is 0.5 to
It is preferably 50% by weight, more preferably 1 to
The content is 30% by weight, more preferably 3 to 25% by weight, particularly preferably 4 to 20% by weight. When the conductive metal to be coated is gold, the coating amount is from 2.5 to 2.5
It is preferably 30% by weight, more preferably 3 to
It is 20% by weight, more preferably 3.5 to 15% by weight. When the conductive metal to be coated is silver,
The coating amount is preferably 3 to 50% by weight of the core particles, more preferably 4 to 40% by weight, further preferably 5 to 30% by weight, particularly preferably 6 to 20% by weight.

The conductive particles have a particle size of 1 to 100.
0 μm, more preferably 2 to 50 μm.
0 μm, more preferably 5 to 300 μm, particularly preferably 10 to 200 μm. Further, the particle size distribution (Dw / Dn) of the conductive particles is preferably 1 to 10, more preferably 1.01 to 7, further preferably 1.05 to 5, and particularly preferably 1.1 to 1. 4. By using conductive particles that satisfy such conditions,
The conductive portion of the obtained anisotropic conductive sheet is easily deformed under pressure, and sufficient electrical contact between the conductive particles is obtained in the conductive portion. 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 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, particularly preferably 1% or less. By using the conductive particles satisfying such conditions, it is possible to prevent bubbles from being generated in the polymer material layer when the polymer material layer is cured in the manufacturing method described below or Is suppressed.

As the conductive particles, those whose surfaces have been treated with a coupling agent such as a silane coupling agent can be used as appropriate. By treating the surface of the conductive particles with the coupling agent, the adhesion between the conductive particles and the elastic polymer material is increased, and as a result, the conductive portion of the obtained anisotropic conductive sheet has a repetitive structure. The durability in use becomes high. 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). Is preferably 5% or more, more preferably 7 to 100%, more preferably 10 to 100%, and particularly preferably 20 to 100%.
It is an amount that becomes 100%.

Such conductive particles are used in such a proportion that the proportion of the conductive particles in the conductive portion of the obtained anisotropic conductive sheet is 30 to 60% by volume, preferably 35 to 50%. Is preferred. If this ratio is less than 30%, a conductive portion having a sufficiently low electric resistance may not be obtained. On the other hand, when this ratio exceeds 60%, the conductive part of the obtained anisotropic conductive sheet tends to be fragile, and the elasticity required for the conductive part may not be obtained.

The sheet molding material may contain a curing catalyst for curing the polymer 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 material, the type of the curing catalyst, and other curing conditions. 15 parts by weight.

The sheet molding material may contain, if necessary, an ordinary inorganic filler such as silica powder, colloidal silica, airgel silica, and alumina. By including such an inorganic filler,
The thixotropy of the sheet molding material is ensured, the viscosity is increased, and the dispersion stability of the conductive particles is improved, and the strength of the obtained anisotropic conductive sheet is increased. The use amount of such an inorganic filler is not particularly limited, but using a large amount is not preferable because the orientation of the conductive particles cannot be sufficiently achieved by the magnetic field. The viscosity of the sheet molding material is preferably in the range of 10,000 to 1,000,000 cp at a temperature of 25 ° C.

Then, the upper die of the mold for forming the anisotropic conductive sheet
And placing an electromagnet on the lower mold to activate it
Through the upper mold and the lower mold to form the sheet molding material layer 1A.
A magnetic field having an intensity distribution in the thickness direction is applied. Concrete
Specifically, a conductive portion in the sheet molding material layer 1A is formed.
Part to be formed (hereinafter, also referred to as “conductive part forming part”)
That is, the portion located between the high magnetic field forming portions H has the largest size.
Magnetic flux density B_HA magnetic field having a force is applied, and a conductive portion forming portion is formed.
In the peripheral portion of, that is, the portion located between the middle magnetic field forming portions M
Is the magnetic flux density B at the conductive portion forming portion._HLess than
Magnetic flux density B_MA magnetic field having a force is applied, and a conductive portion forming portion is formed.
And a portion other than its peripheral portion, that is, a low magnetic field forming portion L
The part located between them is the part located between the middle magnetic field forming parts M
Flux density B in minutes_MEven smaller magnetic flux density B _L
Is formed. As a result, the sheet molding material
The layer 1A is dispersed in the sheet forming material layer 1A.
Of the conductive particles that have been positioned between the low magnetic field forming portions L
The conductive particles present in the part where
Move to the part that is located, that is, the peripheral part of the conductive part forming part
I do. Also, it exists in a portion located between the middle magnetic field forming portions M.
Conductive particles are located between the high magnetic field forming portions H.
That is, it moves to the conductive portion forming portion. In this way, the sea
Of the conductive particles dispersed in the molding material layer 1A
Or most of the time, as shown in FIG.
Collected in the conductive portion forming portion of the layer 1A, more preferably
Are oriented in the thickness direction of the sheet forming material layer 1A.

In the above, in the sheet forming material layer
Magnetic flux density of the magnetic field applied to the periphery of the conductive part
B_MIs the magnetic flux density of the magnetic field applied to the conductive part.
Degree B _HIs preferably 30% to 90%, more preferably
Or 30 to 60%. In addition, the conductive part forming part and
Density of the magnetic field applied to parts other than the surrounding area
B_LIs the magnetic field applied to the periphery of the conductive part.
Magnetic flux density B_MIs preferably 80% or less. that's all
, The magnetic flux density B_MIs the magnetic flux density B_HLess than 30% of
In some cases, the magnetic flux density B_MAnd magnetic flux density B_LDifference between
Value) is too small, so that the
Exists in parts other than the electrical part forming part and its surrounding parts
Reliable transfer of conductive particles to the area around the conductive part
Can be difficult. On the other hand, the magnetic flux density B
_MIs the magnetic flux density B_HOver 90% of the magnetic flux density
B_HAnd magnetic flux density B_MOr the difference (absolute value) is too small
Around the conductive part forming part in the sheet molding material layer
Conductive particles present in the conductive part
Can be difficult to move. Also, the magnetic flux density
B_LIs the magnetic flux density B_MOver 80% of the magnetic flux density
Degree B_MAnd magnetic flux density B_LDifference (absolute value) becomes too small
Therefore, the conductive part forming portion and the sheet forming material layer
Conductive particles that are present in areas other than the surrounding area
It is difficult to reliably move to the peripheral part of the forming part.
Sometimes.

Formation of conductive part in sheet molding material layer 1A
Flux density B of the magnetic field applied to the part _HIs 0.0
2-1 Wb / m^TwoIt is preferred that Sheet molding material
Of the magnetic field applied to the conductive portion forming portion in the material layer 1A
Bundle density B _HAnd the peripheral portion of the conductive portion forming portion
Flux density B of the magnetic field_M(Absolute value) is 0.01 to
0.09Wb / m^TwoIs preferred, and more preferred
0.02 to 0.09 Wb / m^TwoIt is. Sheet molding
Acting on the peripheral portion of the conductive layer forming portion in the material layer 1A
The magnetic flux density B of the magnetic field_MAnd the conductive part forming part and its periphery
The magnetic flux density B of the magnetic field applied to portions other than the side portions_LWith
The difference (absolute value) is 0.08 Wb / m^TwoTo be
Preferably, more preferably, 0.06 Wb / m^TwoBelow
You.

As means for applying a parallel magnetic field, a permanent magnet can be used instead of an electromagnet. As such a permanent magnet, those made of alnico (Fe-Al-Ni-Co-based alloy), ferrite, or the like are preferable in that a parallel magnetic field strength in the above range can be obtained.

Then, in this state, the sheet forming material layer 1A was cured and released from the anisotropic conductive sheet forming die, so that the conductive particles were densely filled as shown in FIG. An anisotropic conductive sheet 1 having a conductive portion 2 and an insulating portion 3 having no or almost no conductive particles is obtained. The curing treatment of the sheet molding material layer 1A is as follows.
Although it is appropriately selected depending on the material used, it is usually performed by a heat treatment. Sheet forming material layer 1 by heating
In the case of performing the curing treatment of A, the specific heating temperature and heating time are appropriately determined in consideration of the type of the material for the polymer substance constituting the sheet molding material layer 1A, the time required for the movement of the conductive particles, and the like. Selected. The curing treatment of the sheet molding material layer 1A can be performed in a state where the parallel magnetic field is applied, but can also be performed after stopping the operation of the parallel magnetic field. In the conductive portion 2 thus obtained, since the conductive particles are oriented so as to be arranged in the thickness direction of the anisotropic conductive sheet 1, good conductivity can be obtained even if the ratio of the conductive particles is small.

According to such a method, the sheet molding material
The magnetic field applied to the layer is applied to the area around the conductive part.
Magnetic flux density B_MIs the magnetic flux density in the conductive part formation part.
Degree B _HLower and conductive part forming part and its periphery
Magnetic flux density B in other parts_LIs the conductive part
Flux density B in the peripheral part of the part_MLower
Conductive part forming part in the sheet molding material layer and the conductive part forming part
The conductive particles present in the parts other than the peripheral part are
To the periphery of the component, and then
Can be moved. Therefore, the conductive part formation part
Conductive particles located at locations where the distance in the
It can be reliably moved to the conductive part forming part.
Even if the area of the non-functional region is large, the conductive portion
Is filled with the required amount of conductive particles, and
No or very few anisotropic conductive particles
Sheets can be manufactured.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various changes can be made. (1) The method of manufacturing the mold of the present invention is not limited to the above-described first method and second method. For example, as a method of forming the first protruding magnetic body, etching may be performed by etching. Instead of the above method, a method of plating the surface of the magnetic substrate, a method of bonding a thin plate made of a magnetic material to the surface of the magnetic substrate by appropriate means, or the like can be adopted. (2) The specific configuration of the mold according to the present invention includes a high magnetic field forming unit, a medium magnetic field forming unit, and a low magnetic field forming unit.
The configuration is not limited to the one shown in FIG. 1, and various configurations can be adopted. For example, the nonmagnetic layer and the cavity forming layer are not essential for the mold of the present invention. Further, the high magnetic field forming section and the medium magnetic field forming section may have a configuration other than the configuration using the first protruding magnetic body section and the second protruding magnetic body. (3) The method for producing an anisotropic conductive sheet is characterized in that, in a magnetic field applied to a sheet forming material layer, a magnetic flux density B _H in a conductive portion forming portion, a magnetic flux density B _M in a peripheral portion of the conductive portion forming portion, The magnetic flux density B _L in the portion other than the conductive portion forming portion and its peripheral portion is B _H > B _M
As long as the condition of> _BL is achieved, the method is not limited to the method using the mold shown in FIG. 1 and various methods can be adopted.

[0051]

The present invention will be described in detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Example 1 (1) Production of Mold for Forming Anisotropic Conductive Sheet: Thickness (D
1) Prepare an A4 size iron plate (11) having a thickness of 6 mm, laminate a dry film resist having a thickness of 50 μm on one surface of the iron plate (11), and expose with a high pressure mercury lamp as a light source at an exposure amount of 80 mJ / cm ^2. After the treatment, the resist layer (21) is spray-developed for 1 minute using a 1% aqueous sodium hydrogencarbonate solution as a developing solution according to a pattern corresponding to the second protruding magnetic body portion to be formed.
Was formed (see FIGS. 2 and 3). Then, by using a ferric chloride aqueous solution (Bohm concentration 40) as an etching solution and performing an etching treatment at 40 ° C. for 1.5 minutes by a spray method, a plurality of second protruding magnetic portions (20) are formed. Was formed (see FIG. 4). The second protruding magnetic body (20) has a dimension in the plane direction of 350 μm × 350.
μm (the cross-sectional area in the plane direction is 0.035 mm ² ), the protrusion height (h2) is 100 μm, and the pitch is 500 μm.
It is arranged in a frame shape along the four sides of the rectangle, and the size of the rectangle surrounded by the second protruding magnetic body (20) is 8 mm.
× 12 mm.

Next, after removing the resist layer (21) from the surface of the second protruding magnetic body portion (20), the thickness of the surface of the second protruding magnetic body portion (20) and the peripheral surface thereof is reduced. Laminate 50μm dry film resist,
After performing an exposure process using a high-pressure mercury lamp as a light source at an exposure amount of 80 mJ / cm ² , spray development is performed for 1 minute using a 1% aqueous sodium hydrogen carbonate solution as a developing solution.
A resist layer (22) was formed corresponding to the first protruding magnetic body to be formed (see FIG. 5). Then, using an aqueous solution of ferric chloride (Bohm concentration 40) as an etching solution,
The magnetic substrate (10) and the first protruding magnetic portion (15) protruding from the surface of the magnetic substrate (10) were formed by etching at 40 ° C. for 3 minutes by a spray method. (See FIG. 6). Magnetic substrate (1
The thickness (D) of (0) is 4.64 mm, the first protruding magnetic body (15) has a rectangular frame shape, the outer dimension is 9 mm × 13 mm, and the inner dimension is 4mm x 8m
m, the cross-sectional area in the plane direction is 0.75 mm ² (21 times the cross-sectional area of the second protruding magnetic body portion). In addition, the magnetic substrate (1
The thickness of 0) is 4.64 mm.

Next, after the resist layer (22) is removed from the surface of the first protruding magnetic body (15) and the surface of the second protruding magnetic body (20), the surface of the magnetic substrate (10) and An acrylic resin material is applied to the surface of the first protruding magnetic body portion (15) to form a thermosetting resin layer, and the thermosetting resin material layer is cured at 160 ° C. for 120 minutes. Thus, a nonmagnetic layer (30) was formed (see FIG. 7). Then, the nonmagnetic layer (30) and the second
A photoresist layer (37) was formed by laminating a dry film resist having a thickness of 50 μm on the surface of the protruding magnetic body portion (20). On the surface of the photoresist layer (37), a mask on which a radiation shielding portion is formed is positioned and arranged in accordance with a pattern corresponding to a hole of a cavity forming layer to be formed. 80mJ using high pressure mercury lamp as light source
After performing a radiation irradiation treatment at an exposure amount of / cm ² , a lower mold was manufactured by forming a cavity forming layer by performing spray development for 1 minute using a 1% aqueous sodium hydrogen carbonate solution as a developing solution. In the same manner as above,
By forming the second protruding magnetic body portion, the first protruding magnetic body portion, the magnetic substrate, the non-magnetic material layer, and the cavity forming layer, an upper mold paired with the lower mold is manufactured. An anisotropic conductive sheet molding die was manufactured.

(2) Production of anisotropic conductive sheet: A fluorine-based release agent “Daifree A44” was applied to the molding surfaces of the upper and lower molds.
1 "(manufactured by Daikin Industries, Ltd.) was spray applied. Next, a polyimide sheet having a thickness of 100 μm is used as a frame-shaped spacer, and a sheet molding material in which nickel particles having an average particle diameter of 40 μm are contained in a room-temperature-curable silicone rubber in a ratio of 25% by volume is placed in a mold. Injected. An electromagnet is disposed on the upper surface of the upper die and the lower surface of the lower die in this mold and operated. In this state, the conductive portion protruding from the surface of the insulating portion is heated by heating at 120 ° C. for 30 minutes. An anisotropic conductive sheet having the same was manufactured. As described above, the magnetic flux density of the magnetic field applied between the second protruding magnetic body portions in the upper mold and the lower mold is 0.8 Wb / m ² ,
The magnetic flux density of the magnetic field applied between the first protruding magnetic body portion (excluding the portion where the second protruding magnetic body portion exists) is 0.4 W
b / m ² , and the magnetic flux density of the magnetic field applied between the magnetic substrate (excluding the portion where the first protruding magnetic portion exists) is 0.3
Wb / m ² . Each obtained anisotropic conductive sheet,
Conductive parts having an insulating part with a thickness of 0.18 mm, dimensions in the plane direction of 350 μm × 350 μm, and a protrusion height of 50 μm, are arranged in a frame along the four sides of a rectangle at a pitch of 500 μm. Met.

(3) Evaluation of anisotropically conductive sheet: As shown in FIG. 19, the obtained anisotropically conductive sheet 1 was subjected to a resistance measuring instrument 40 (“Milliohm High Tester” manufactured by Hioki Electric Co., Ltd.) and a probe pin. 41, short-circuit plate 42, lead wire 43
When the electric resistance of the conductive part 2 was measured using the resistance measuring device constituted by the above, it was 200 mΩ, and it was confirmed that the conductive part 2 had high conductivity. Further, when the electric resistance in the thickness direction of the insulating portion 3 was measured at 10 points in the non-functional region using this resistance measuring apparatus, the minimum value was 3 MΩ. As shown in FIG. 20, an anisotropic conductive sheet is formed by using a resistance measuring device 40 ("Milliohm Hi Tester" manufactured by Hioki Electric Co., Ltd.), a pair of probe pins 41, and a lead wire 43. 1
When the electric resistance between the adjacent conductive parts 2 was measured, it was 2 MΩ. When the non-functional region of the anisotropic conductive sheet was observed, almost no conductive particles were present in the non-functional region.

<Comparative Example 1> Instead of the first protruding magnetic body and the second protruding magnetic body, the dimension in the plane direction was 350 μm.
The anisotropic conductive sheet molding die according to Example 1, except that the protruding magnetic body portions having a size of × 350 μm and a protruding height of 360 μm are arranged in a frame along four sides of a rectangle at a pitch of 500 μm. A mold for forming an anisotropic conductive sheet having the same configuration was manufactured, and an anisotropic conductive sheet was manufactured in the same manner as in Example 1. As described above, the magnetic flux density of the magnetic field applied between the protruding magnetic body portions in the upper mold and the lower mold is 0.8 Wb.
/ M ^2, the magnetic flux density of the magnetic field acting between the parts other than the projecting magnetic portion was 0.3Wb / m ^2. The same evaluation as in Example 1 was performed on the obtained anisotropic conductive sheet. As a result, the value of the electric resistance of the conductive portion was 300 mΩ,
The minimum value of the electric resistance in the thickness direction of the insulating part was 2 MΩ, and the value of the electric resistance between adjacent conductive parts was 1 MΩ. When the non-functional region of the anisotropic conductive sheet was observed, a large number of conductive particles existing in the non-functional region were found.

[0058]

According to the mold of the present invention, since the low magnetic field forming portion is provided around the high magnetic field forming portion via the medium magnetic field forming portion, the conductive particles formed in the molding space are provided. Are dispersed in the sheet molding material layer, the conductive particles present in the portion of the sheet molding material layer located on the low magnetic field forming portion are the medium magnetic field forming portions M where a magnetic field having a higher magnetic flux density acts than the portion. Then, it moves to a portion located on the high magnetic field forming portion where a magnetic field having a higher magnetic flux density acts than that portion, that is, a portion where a conductive portion is to be formed. Therefore, the conductive particles present at a location where the distance to the portion located on the high magnetic field forming portion is considerably long can be reliably moved to the portion located on the high magnetic field forming portion, and the non-functional region Even if the area is large, the conductive portion is filled with a required amount of conductive particles, and the anisotropic conductive sheet having no or very few conductive particles present in the insulating portion can be formed. .

According to the method for producing an anisotropic conductive sheet of the present invention, the magnetic field applied to the sheet forming material layer is such that the magnetic flux density B _M in the peripheral portion of the conductive portion forming portion is the magnetic flux density in the conductive portion forming portion. B _H and the magnetic flux density B _L in portions other than the conductive portion forming portion and its peripheral portion is lower than the magnetic flux density B _M in the peripheral portion of the conductive portion forming portion. The conductive particles present in the portion other than the portion and the peripheral portion thereof can be moved to the peripheral portion of the conductive portion forming portion, and then can be moved to the conductive portion forming portion. Therefore, since the conductive particles present at a place where the distance to the conductive portion forming portion is considerably long can be reliably moved to the conductive portion forming portion, even if the area of the non-functional region is large, It is possible to manufacture an anisotropic conductive sheet in which the conductive portion is filled with a required amount of conductive particles and has no or very few conductive particles existing in the insulating portion.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing a configuration of a main part of a lower mold in an example of a mold for forming an anisotropic conductive sheet according to the present invention.

FIG. 2 is an explanatory cross-sectional view illustrating an example of a magnetic plate-like body used in manufacturing the anisotropic conductive sheet molding die illustrated in FIG.

FIG. 3 is an explanatory cross-sectional view showing a state in which a resist layer is formed on one surface of the plate-like body shown in FIG. 2;

FIG. 4 is an explanatory sectional view showing a state in which a second protruding magnetic body portion is formed on a plate-like body.

FIG. 5 is an explanatory sectional view showing a state in which a resist layer is formed on the surface of a second protruding magnetic body.

FIG. 6 is an explanatory cross-sectional view showing a state where a magnetic substrate and a first protruding magnetic body are formed.

FIG. 7 is an explanatory cross-sectional view showing a state in which a nonmagnetic layer is formed on the surfaces of a magnetic substrate and a first protruding magnetic body.

FIG. 8 is an explanatory cross-sectional view showing a state where a photoresist layer is formed on the surfaces of a second protruding magnetic body portion and a non-magnetic material layer.

9 is an explanatory cross-sectional view showing another example of a magnetic plate member used for manufacturing the mold for forming an anisotropic conductive sheet shown in FIG. 1;

FIG. 10 is an explanatory cross-sectional view showing a state where a resist layer is formed on one surface of the plate-like body shown in FIG. 9;

FIG. 11 is an explanatory cross-sectional view showing a state in which a magnetic substrate and a first protruding magnetic member are formed.

FIG. 12 is an explanatory cross-sectional view showing a state in which a nonmagnetic base layer portion is formed on the surface of a magnetic substrate.

FIG. 13 is an explanatory cross-sectional view showing a state where a photoresist layer is formed on the surface of the nonmagnetic base layer portion and the first protruding magnetic body portion.

FIG. 14 is an explanatory sectional view showing a state where a nonmagnetic layer is formed.

FIG. 15 is an explanatory cross-sectional view showing a state in which a second protruding magnetic body is formed on the surface of the first protruding magnetic body.

FIG. 16 is an explanatory cross-sectional view showing a state in which a molding material layer is formed in a mold for molding an anisotropic conductive sheet.

FIG. 17 is an explanatory cross-sectional view showing a state in which a magnetic field having an intensity distribution is applied to a molding material layer in a mold for molding an anisotropic conductive sheet.

FIG. 18 is an explanatory cross-sectional view illustrating a configuration of an example of an anisotropic conductive sheet obtained by a manufacturing method of the present invention.

FIG. 19 is an explanatory view showing an apparatus for measuring the resistance of a conductive portion in an anisotropic conductive sheet manufactured in an example.

FIG. 20 is an explanatory view showing an apparatus for measuring a resistance between adjacent conductive portions in an anisotropic conductive sheet manufactured in an example.

[Description of Signs] 1 Anisotropic conductive sheet 1A Sheet forming material layer 2 Conductive part 3 Insulating part 10 Magnetic substrate 11, 12 Plate 15 First protruding magnetic body 20 Second protruding magnetic body 21, 22, 23 resist layer 30 nonmagnetic layer 31 nonmagnetic base layer 32 nonmagnetic upper layer 32A photoresist layer 33 through hole 35 cavity forming layer 36 hole 37 photoresist layer 40 resistance measuring instrument 41 probe pin 42 shorting plate 43 Lead

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F202 AA21 AA39 AA40 AE03 AH33 AH34 CA27 CB01 CC10 CK09 CL42 4F211 AA21 AA39 AA40 AE03 AH33 AH34 SC07 SD01 SD16 SG02 SJ01 SK06 SP02 5G323 AA01

Claims (8)

[Claims] 1. A mold comprising an upper mold and a lower mold to be paired with the upper mold, wherein a molding space is formed between the upper mold and the lower mold, wherein the upper mold and the lower mold are provided. At least one of the plurality of high magnetic field forming portions, which are provided apart from each other along the surface direction and form a magnetic field having a high magnetic flux density in the thickness direction of the molding space, and are provided around the high magnetic field forming portion. A medium magnetic field forming section that forms a magnetic field having a lower magnetic flux density than the high magnetic field forming section in the thickness direction of the molding space; and a magnetic flux provided around the medium magnetic field forming section and higher than the medium magnetic field forming section. A mold having a low magnetic field forming section for forming a low density magnetic field in the thickness direction of the molding space. 2. The mold according to claim 1, which is used for forming an anisotropic conductive sheet. 3. The sectional area in the plane direction in the medium magnetic field forming section is 1.2 to 3 times the sectional area in the plane direction in the high magnetic field forming section.
The mold according to claim 1 or 2, wherein the ratio is zero. 4. A magnetic substrate, and a first protruding magnetic member provided at a portion of the magnetic substrate where the high magnetic field forming portion and the medium magnetic field forming portion are located so as to protrude from the surface of the magnetic substrate. And a second protruding magnetic body portion provided at a portion of the first protruding magnetic body portion where the high magnetic field forming portion is located so as to protrude from a surface of the first protruding magnetic body portion. The mold according to any one of claims 1 to 3, wherein: 5. A plurality of conductive portions extending in a thickness direction are insulating portions.
Anisotropic conductors arranged insulated from each other by
A method for producing an electrically conductive sheet, comprising: curing an elastic polymer material into an elastic polymer material by being cured;
Sheet molding material containing conductive particles exhibiting magnetism
For a layer, a magnetic field having an intensity distribution is applied to the thickness of the molding material.
And cure the sheet molding material layer
Processing step, wherein in this step, the conductive portion of the sheet molding material layer is formed.
The magnetic flux density at the part to be formed is B_H, Shape the conductive part
The magnetic flux density around the part to be formed is B _M,
A portion other than the portion where the conductive portion is to be formed and its peripheral portion
The magnetic flux density at_LAnd B_H> B_M> B_L
For producing an anisotropic conductive sheet characterized by satisfying the following conditions:
Law. 6. The magnetic flux density B _M is 30 to 9 of the magnetic flux density B _H.
The method for producing an anisotropic conductive sheet according to claim 5, wherein the content is 0%. 7. anisotropic conductive sheet manufacturing method according to claim 5 or claim 6 the magnetic flux density B _L is equal to or less than 80% of the magnetic flux density B _M. 8. A sheet molding material layer is formed in the mold using the mold according to any one of claims 1 to 4, and a strength distribution is formed on the sheet molding material layer via the mold. The method for producing an anisotropic conductive sheet according to any one of claims 5 to 7, wherein a magnetic field having the following is applied.