WO2005101589A1

WO2005101589A1 - Die for manufacturing anisotropic conductive sheet and method for manufacturing anisotropic conductive sheet

Info

Publication number: WO2005101589A1
Application number: PCT/JP2005/007035
Authority: WO
Inventors: Masaya Naoi
Original assignee: Jsr Corporation
Priority date: 2004-04-14
Filing date: 2005-04-11
Publication date: 2005-10-27
Also published as: TW200603486A; KR20070010012A; CN1943081A

Abstract

A die for manufacturing an anisotropic conductive sheet and a method for manufacturing the anisotropic conductive sheet are provided for manufacturing the anisotropic conductive sheet, which has conductive path forming parts exhibiting a prescribed conductivity even when the pitch of the conductive path forming parts to be formed is small, and surely provides prescribed insulation between the adjacent conductive path forming parts. The die for manufacturing the anisotropic conductive sheet is provided for manufacturing the anisotropic conductive sheet having a plurality of the conductive path forming parts containing conductive particles in a condition where the conductive particles exhibiting magnetism are oriented in a thickness direction in an insulating elastic polymeric substance, and insulating parts, which are composed of an insulating elastic polymeric substance that insulates the conductive path forming parts from one another. The die is composed of a board, and a ferromagnetic layer, which is arranged on the board in accordance with a pattern that corresponds to a pattern of the conductive path forming parts. The board is made of a feeble magnetic material.

Description

Specification

TECHNICAL FIELD The present invention relates to a mold for producing an anisotropic conductive sheet and a method for producing an anisotropic conductive sheet.

The present invention relates to a mold for producing an anisotropic conductive sheet and a method for producing an anisotropic conductive sheet.

More specifically, an anisotropic device that can be suitably used for electrical inspection of circuit devices such as integrated circuits formed on a wafer, integrated circuits obtained by dicing the wafer, cage ICs, and printed circuit boards. The present invention relates to a mold for manufacturing an anisotropic conductive sheet for manufacturing a conductive sheet and a method for manufacturing an anisotropic conductive sheet.

Background art

[0002] An anisotropic conductive elastomer sheet is a sheet having conductivity only in the thickness direction, or a sheet having a pressurized conductive portion which is conductive 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, and liquid crystal panels can be used in fields such as electronic calculators, electronic digital watches, electronic cameras, and computer keyboards. It is widely used as a connector to achieve an electrical connection between them.

[0003] Further, in an electrical inspection of a circuit device such as a semiconductor integrated circuit device such as a knock IC, an MCM, an integrated circuit formed thereon, and a printed circuit board, a circuit device to be inspected has one surface. In order to achieve electrical connection between the formed test electrode and the test electrode formed on the surface of the test circuit board, the test device electrode area of the circuit device to be tested and the test circuit board An anisotropic conductive elastomer sheet is interposed between the test electrode region and the test electrode region.

[0004] Conventionally, as such an anisotropic conductive elastomer sheet, those having various structures are known. For example, Patent Document 1 and the like disclose thick conductive particles exhibiting magnetism in the elastomer. Anisotropic conductive sheet obtained by dispersing in a state aligned in Is referred to as a “dispersion type anisotropic conductive sheet”. Patent Document 2 and the like disclose a non-uniform distribution of conductive particles exhibiting magnetism in an elastomer, thereby forming a large number of conductive path forming portions extending in the thickness direction and interconnecting these portions. An anisotropic conductive sheet (hereinafter referred to as a “distributed anisotropic conductive sheet”) in which an insulating portion to be insulated is formed is disclosed. Further, Patent Document 3 and the like disclose a conductive path forming portion. An unevenly distributed anisotropic conductive sheet in which a step is formed between a surface and an insulating portion is disclosed.

Among these anisotropic conductive elastomer sheets, the unevenly distributed anisotropic conductive sheet has a conductive path forming portion formed in accordance with a pattern corresponding to a pattern of an electrode to be connected, and a conductive path forming portion is formed between adjacent conductive path forming portions. Since the insulating portion is formed, high reliability and electrical connection can be achieved even when the electrodes to be connected are arranged at a small pitch as compared with the dispersion type anisotropic conductive sheet. In that respect, it is advantageous.

In order to manufacture such an unevenly distributed anisotropically conductive sheet, a special anisotropically conductive sheet manufacturing die having a configuration shown in FIG. 10, for example, has been conventionally used. This mold for producing an anisotropic conductive sheet is composed of an upper mold 90 and a lower mold 95, which is a pair of the upper mold 90, arranged so that their molding surfaces face each other. The cavity is formed between the lower surface of the lower mold 95 and the molding surface of the lower mold 95 (the upper surface in FIG. 10). In the upper die 90, a ferromagnetic layer 92 is formed on the lower surface of the ferromagnetic substrate 91 according to a pattern opposite to the arrangement pattern of the conductive path forming portions of the anisotropic conductive sheet to be manufactured. A weak magnetic layer 93 is formed in a portion other than the body layer 92. On the other hand, in the lower mold 95, a ferromagnetic layer 97 is formed on the upper surface of the ferromagnetic substrate 96 according to the same pattern as the arrangement pattern of the conductive path forming portions of the anisotropic conductive sheet to be manufactured. A weak magnetic layer 98 is formed in a portion other than the body layer 97.

Then, using this mold for producing an anisotropic conductive sheet, an unevenly distributed anisotropic conductive sheet is obtained as follows.

First, as shown in FIG. 11, in a mold for producing an anisotropic conductive sheet, a conductive material obtained by dispersing conductive particles P exhibiting magnetism in a polymer forming material which is cured to become an elastic polymer material. A material layer 80 is formed. Next, a pair of electromagnets (not shown) are arranged on the upper surface of the upper die 90 and the lower surface of the lower die 95 and actuated. A magnetic field having a larger intensity is applied to a portion located between the ferromagnetic layer 92 of the upper die 90 and the ferromagnetic layer 97 of the lower die 95. As a result, the conductive particles P dispersed in the conductive material layer 80 are located between the ferromagnetic layer 92 of the upper die 90 and the ferromagnetic layer 97 of the lower die 95, that is, a conductive path is formed. Assemble into the part that will be the part, and be aligned in the thickness direction. Then, by conducting a curing treatment of the conductive material layer 80 in this state, an unevenly distributed anisotropic conductive sheet is obtained.

[0006] However, it has been found that the conventional mold for producing an anisotropic conductive sheet has the following problems.

(1) In the step of applying a magnetic field to the conductive material layer 80, the ferromagnetic substrates 91 and 96 themselves function as magnetic poles, so that the portions of the conductive material layer 80 that become insulating portions also have weak magnetic properties. Since a magnetic field acts through the body layers 93 and 98, the conductive particles P present in the portion of the conductive material layer 80 that will become the insulating portion remain without moving toward the portion that becomes the conductive path forming portion. It's easy to do. As a result, an insulating portion having a required insulating property is not formed, and furthermore, a conductive path forming portion containing a required amount of the conductive particles P is not reliably formed. Is difficult to obtain. Such a phenomenon is more remarkable as the pitch of the conductive path forming portion is smaller.

[0007] (2) In order to produce an anisotropic conductive sheet exhibiting high conductivity with a small pressing force, in the step of applying a magnetic field to the conductive material layer, the thickness direction, that is, the surface of the conductive material layer, is required. It is important to form a chain of conductive particles in a direction perpendicular to. However, in the conductive material layer before applying a magnetic field, since the conductive particles are present in a state of being uniformly dispersed in the conductive material layer, the magnetic field is applied in the thickness direction of the conductive material layer. However, as shown in FIG. 12, the chain of the conductive particles P is formed not only in the thickness direction of the conductive material layer 80 but also in a direction inclined with respect to the thickness direction. In this state, the conductive force is also magnetodynamically stable, and the individual conductive particles are constrained by the magnetic force, so that the conductive particles form a chain in the thickness direction even when the action of the magnetic field is continued. Never move as you do. Then, in this state, the conductive material layer 80 is cured, whereby the obtained anisotropic conductive sheet is also formed in a direction in which the chain of the conductive particles is inclined with respect to the thickness direction. Therefore, high conductivity can be obtained with a small pressing force. It is difficult to obtain.

Further, when a magnetic field is applied to the conductive material layer 80, the conductive particles P remaining in the portion to be the insulating portion are connected to the other conductive particles P, so that the upper die as shown in FIG. A chain of conductive particles P is formed between the ferromagnetic layer 92 of 90 and the ferromagnetic layer 97 adjacent to the ferromagnetic layer 97 of the lower mold 95 corresponding thereto, and as a result, the adjacent conductive layer P It is difficult to obtain an anisotropic conductive sheet having the required insulation between the path forming portions. Such a phenomenon is more remarkable as the pitch of the conductive path forming portion is smaller.

[0008] In order to solve such a problem, the present applicant stops the action of the magnetic field on the conductive material layer in the step of applying the magnetic field to the conductive material layer, and then again performs the action on the conductive material layer. In response to this, for example, a method for producing an anisotropic conductive sheet in which a magnetic field whose direction of magnetic flux lines is opposite to that of a magnetic field is proposed (see Japanese Patent Application No. 2004-30180).

According to such a manufacturing method, since the action of the magnetic field on the conductive material layer is temporarily stopped, in this stopped state, the individual conductive particles in the conductive material layer are released from the restraint by the magnetic force. . Then, by applying a magnetic field in which the direction of the magnetic flux lines in the thickness direction is opposite to that of the conductive material layer again, this operation triggers and the movement of the conductive particles starts again. A chain of conductive particles is formed in a direction more faithful to the thickness direction of the conductive material layer.

However, in such a manufacturing method, the magnetic force generated when a magnetic field in which the direction of the magnetic flux lines is applied to the conductive material layer is opposite to that in the anisotropic conductive sheet manufacturing mold. Each of the ferromagnetic substrates of the mold and the lower mold moves, thereby causing a displacement between the upper mold and the lower mold as shown in FIG. For this reason, in the obtained anisotropic conductive sheet, a conductive path forming portion extending in a direction inclined with respect to the thickness direction is formed, so that it is difficult to obtain the desired conductivity. In addition, when the ferromagnetic substrate of each of the upper mold and the lower mold moves, air enters the mold for producing an anisotropic conductive sheet, so that bubbles are easily generated in the obtained anisotropic conductive sheet. There is a problem.

Patent Document 1: JP-A-51-93393

Patent Document 2: JP-A-53-147772

Patent Document 3: JP-A-61-250906 Disclosure of the invention

[0010] The present invention has been made in view of the above circumstances, and a first object of the present invention is to provide a plurality of conductive path forming portions containing conductive particles, and a method for forming these conductive paths. In a mold for manufacturing an anisotropic conductive sheet having an insulating part that insulates parts from each other, even if the pitch of the conductive path forming part to be formed is small, A conductive path forming portion exhibiting the above-mentioned conductivity, and a mold for manufacturing an anisotropic conductive sheet capable of manufacturing an anisotropic conductive sheet that can reliably obtain required insulation between adjacent conductive path forming portions. To provide.

A second object of the present invention is to manufacture an anisotropic conductive sheet having a plurality of conductive path forming portions containing conductive particles, and an insulating portion for insulating these conductive path forming portions from each other. In this method, even if the pitch of the conductive path forming portion to be formed is small, the conductive path forming portion having the intended conductivity is provided, and the required insulation between the adjacent conductive path forming portions is ensured. To provide a method for producing an anisotropic conductive sheet obtained by the method described above.

[0011] The mold for producing an anisotropic conductive sheet according to the present invention includes a plurality of conductive path forming portions each containing a conductive particle exhibiting magnetism in a state of being oriented in a thickness direction in an insulating elastic polymer material. And an anisotropic conductive sheet manufacturing mold for manufacturing an anisotropic conductive sheet having an insulating portion made of an insulating elastic polymer material that insulates these conductive path forming portions from each other. And a ferromagnetic layer disposed on the substrate according to a pattern corresponding to the pattern of the conductive path forming portion,

The substrate is made of a weak magnetic material.

[0012] The mold for producing an anisotropic conductive sheet of the present invention has a conductive polymer in a liquid polymer-forming material which is cured to become an insulating elastic polymer substance in a mold for producing an anisotropic conductive sheet. A conductive material layer containing particles is formed, and the conductive material layer is formed on the conductive material layer in the thickness direction of the conductive material layer via the ferromagnetic layer in the anisotropic conductive sheet manufacturing mold. A step of assembling conductive particles in a portion to be the conductive path forming portion by applying a magnetic field and orienting the conductive particles in a thickness direction of the conductive material layer; After stopping the action of the magnetic field, the magnetic material is again applied to the conductive material layer. The method can be suitably used for a method for producing an anisotropic conductive sheet in which an operation for applying a field is performed at least once.

[0013] In the anisotropic conductive sheet manufacturing mold of the present invention, the substrate is preferably linear thermal expansion coefficient is from 1 X 1 0 one ⁷ ~ ¹ X ^ιο- ⁵ ^κ- 1 of weak magnetic material .

Preferably, a metal film is formed on the surface of the substrate.

[0014] The method for producing an anisotropic conductive sheet according to the present invention comprises a plurality of conductive path forming portions each comprising a conductive particle exhibiting magnetism in an insulating elastic polymer material oriented in a thickness direction. A method of manufacturing an anisotropic conductive sheet having an insulating portion made of an insulating elastic polymer material that insulates these conductive path forming portions from each other,

Using the above anisotropic conductive sheet manufacturing mold,

A conductive material layer containing conductive particles in a liquid polymer-forming material that is cured to become an insulating elastic polymer material is formed in the anisotropic conductive sheet manufacturing mold. By applying a magnetic field to the conductive material layer through the ferromagnetic layer in the anisotropic conductive sheet manufacturing mold in the thickness direction of the conductive material layer, a conductive portion is formed on the conductive path forming portion. Aggregating the conductive particles and orienting them in the thickness direction of the conductive material layer,

In this step, after stopping the action of the magnetic field on the conductive material layer, the operation of applying the magnetic field to the conductive material layer is performed at least once again.

[0015] In the method for producing an anisotropic conductive sheet of the present invention, after stopping the action of the magnetic field on the conductive material layer, the operation of applying the magnetic field to the conductive material layer again causes It is preferable that the direction of the magnetic flux lines of the magnetic field applied again to the conductive material layer is opposite to the direction of the magnetic flux lines of the magnetic field before the stop.

Further, in the method for producing an anisotropic conductive sheet of the present invention, after stopping the action of the magnetic field on the conductive material layer, the operation of applying the magnetic field to the conductive material layer again is performed. U, which is preferably done repeatedly.

In addition, it is preferable that after stopping the action of the magnetic field on the conductive material layer, the operation of applying the magnetic field to the conductive material layer be performed five or more times. According to the mold for producing an anisotropic conductive sheet of the present invention, since the substrate is made of a weak magnetic material, when the magnetic field is applied to the conductive material layer, the conductive Since the strength of the magnetic field acting on the insulating portion in the material layer can be sufficiently reduced, the conductive particles existing in the insulating portion can be surely collected in the conductive path forming portion. As a result, it is possible to form an insulating portion having no or almost no conductive particles, and to form a conductive path forming portion containing a required amount of conductive particles. Therefore, even if the pitch of the conductive path forming portions to be formed is small, the conductive path forming portions exhibiting the desired conductivity are provided, and the required insulation between the adjacent conductive path forming portions can be reliably obtained. Can be manufactured.

Further, in the step of applying a magnetic field to the conductive material layer, after the action of the magnetic field on the conductive material layer is stopped, the production of the anisotropic conductive sheet in which the magnetic field is applied to the conductive material layer is performed again. When used in the method, the ferromagnetic substrate does not move even when a magnetic field in which the direction of the magnetic flux lines is applied to the conductive material layer is opposite, so that a displacement may occur. Therefore, a conductive path forming portion extending in a direction faithful to the thickness direction can be formed, and therefore, an anisotropic conductive sheet having a conductive path forming portion exhibiting expected conductivity can be manufactured. . Further, since air is prevented from entering the mold for producing an anisotropic conductive sheet, the occurrence of defective products due to bubbles can be suppressed.

According to the method for producing an anisotropic conductive sheet of the present invention, since the action of the magnetic field on the conductive material layer is temporarily stopped, the individual conductive particles in the conductive material layer are in this stopped state. Is released from the constraint by the magnetic force. Then, by applying a magnetic field again to the conductive material layer in the thickness direction, this operation is triggered, and the movement of the conductive particles starts again. A chain of conductive particles is formed in a more faithful direction.

As described above, the formation of chains of conductive particles in a direction inclined with respect to the thickness direction can be suppressed, so that even if the pressure is applied with a small pressing force, the electric resistance value is low and the conductive property is stable. Can be produced.

In addition, since a chain of conductive particles that connects adjacent conductive path forming portions is prevented from being formed, even if the pitch of the conductive path forming portions is small, the shape of the adjacent conductive path forming portion is small. It is possible to manufacture an anisotropic conductive sheet that ensures the required insulation between the components.Furthermore, since the substrate for the anisotropic conductive sheet manufacturing mold is made of a weak magnetic material, the conductive When a magnetic field in which the direction of the magnetic flux lines is opposite to the magnetic material layer acts on the ferromagnetic material layer, the ferromagnetic substrate does not move. The conductive path forming portion extending in any direction can be formed, and therefore, an anisotropic conductive sheet having the conductive path forming portion exhibiting the desired conductivity can be manufactured. Further, since air is prevented from entering the mold for producing an anisotropic conductive sheet, the occurrence of defective products due to bubbles can be suppressed.

Brief Description of Drawings

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

FIG. 2 is an enlarged cross-sectional view illustrating a main part of the anisotropic conductive sheet shown in FIG. 1.

FIG. 3 is an explanatory cross-sectional view showing a configuration of a mold for manufacturing an anisotropic conductive sheet used for manufacturing the anisotropic conductive sheet shown in FIG. 1.

FIG. 4 is an explanatory cross-sectional view showing a state where a conductive material is applied to molding surfaces of upper and lower dies in the mold for producing an anisotropic conductive sheet shown in FIG. 1.

FIG. 5 is an explanatory cross-sectional view showing a state in which a conductive material layer is formed in a cavity of a mold for producing an anisotropic conductive sheet.

FIG. 6 is an explanatory cross-sectional view showing a state where a mold for producing an anisotropic conductive sheet is set in an electromagnet device.

FIG. 7 is an explanatory sectional view showing directions of magnetic flux lines in a magnetic field before stop.

FIG. 8 is an explanatory cross-sectional view showing directions of magnetic flux lines in a magnetic field applied again.

FIG. 9 is an explanatory cross-sectional view showing a state where conductive particles in a conductive material layer are gathered at a portion to be a conductive path forming portion and are aligned so as to be arranged in a thickness direction.

FIG. 10 is an explanatory cross-sectional view showing a configuration of an example of a conventional anisotropic conductive sheet manufacturing mold.

[FIG. 11] The conductivity between the upper mold and the lower mold in the mold for producing an anisotropic conductive sheet shown in FIG. It is explanatory sectional drawing which shows the state in which the material layer was formed.

FIG. 12 is an explanatory cross-sectional view showing a state in which a chain of conductive particles in a conductive material layer is formed in a direction inclined with respect to a thickness direction.

[FIG. 13] An explanatory cross-section showing a state in which a chain of conductive particles is formed between the upper ferromagnetic layer and the corresponding ferromagnetic layer adjacent to the lower ferromagnetic layer. FIG.

FIG. 14 is an explanatory cross-sectional view showing a state in which a positional shift has occurred between an upper mold and a lower mold. Explanation of symbols

10 Anisotropic conductive sheet

10A conductive material layer

11 Conductive path forming section

12 Insulation

13, 14 Projection

15 Frame board

50 Upper type

51 substrate

52 Ferromagnetic layer

52a Projection recess

53 weak magnetic layer

53a Cavity recess

55 lower mold

56 substrate

57 Ferromagnetic layer

57a Projection recess

58 weak magnetic layer

58a Cavity recess

60 Electromagnetic device

61 Upper electromagnet

62 magnetic poles 65 Lower electromagnet

66 magnetic poles

80 Conductive material layer

90 Upper type

91 Ferromagnetic substrate

92 Ferromagnetic layer

93 weak magnetic layer

95 lower mold

96 Ferromagnetic substrate

97 Ferromagnetic layer

98 weak magnetic layer

P conductive particles

E elastic polymer material

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail.

The anisotropic conductive sheet 10 includes a plurality of conductive path forming portions 11 extending in the thickness direction, each of which is arranged according to a pattern corresponding to an electrode to be connected, for example, an electrode to be inspected of a circuit device to be inspected. And an insulating portion 12 that insulates the conductive path forming portions 11 from each other. Each of the conductive path forming portions 11 includes conductive particles P in an insulating elastic polymer material E in a state of being aligned in the thickness direction, as shown in an enlarged view in FIG. In addition, by applying pressure in the thickness direction, a conductive path formed by a chain of conductive particles P is formed in the thickness direction. In the illustrated example, each of the conductive path forming portions 11 is formed with protruding portions 13 and 14 protruding from both sides of the insulating portion 12. On the other hand, the insulating portion 12 is made of an insulating elastic polymer material, contains no or almost no conductive particles P, and has conductivity in the thickness direction and the plane direction. Not shown. Further, in the anisotropic conductive sheet of this example, a frame-shaped frame plate 15 is provided integrally with a peripheral portion of the insulating portion 12.

Here, the content ratio of the conductive particles P in the conductive path forming portion 11 is preferably 10 to 60% by volume, and more preferably 15 to 50%. If this ratio is less than 10%, the conductive path forming portion 11 having a sufficiently low electric resistance may not be obtained. On the other hand, if this ratio exceeds 60%, the resulting conductive path forming portion 11 may be fragile or may not immediately have the required elasticity as the conductive path forming portion 11.

Further, the pitch of the conductive path forming portions 11 is, for example, a force of 60 to 500 m. When manufacturing the anisotropic conductive sheet 10 in which the pitch is 200 μm or less, the manufacturing method of the present invention is extremely effective. It is.

FIG. 3 is an explanatory cross-sectional view showing a configuration of an example of the mold for producing an anisotropic conductive sheet of the present invention. This mold for producing an anisotropic conductive sheet is composed of an upper mold 50 and a lower mold 55 that is paired with the upper mold 50 such that their molding surfaces face each other. The cavity is formed between the lower surface of the lower mold 55 and the molding surface of the lower mold 55 (the upper surface in FIG. 3).

In the upper die 50, a ferromagnetic layer 52 is formed on the lower surface of the substrate 51 according to a pattern opposite to the arrangement pattern of the conductive path forming portions 11 of the anisotropic conductive sheet 10 to be manufactured. A weak magnetic layer 53 having a thickness larger than the thickness of the ferromagnetic layer 52 is formed in a portion other than the layer 52, and thereby, the ferromagnetic layer 52 on the molding surface of the upper mold 50 is formed. A protruding portion concave portion 52a for forming the protruding portion 13 in the anisotropic conductive sheet 10 is formed at the position where it is located. On the surface of the weak magnetic layer 53, a cavity recess 53a for forming a cavity is formed.

On the other hand, in the lower mold 55, a ferromagnetic layer 57 is formed on the upper surface of the substrate 56 according to the same pattern as the arrangement pattern of the conductive path forming portions 11 of the anisotropic conductive sheet 10 to be manufactured. A weak magnetic layer 58 having a thickness larger than the thickness of the ferromagnetic layer 57 is formed in a portion other than the body layer 57, and thereby the ferromagnetic layer 57 on the molding surface of the lower mold 55 is positioned. A protruding portion concave portion 57a for forming the protruding portion 14 in the anisotropic conductive sheet 10 is formed at the corresponding position. Also, on the surface of the weak magnetic layer 58, A cavity recess 58a for forming a cavity is formed.

As a material forming the substrates 51 and 56 in each of the upper mold 50 and the lower mold 55, a weak magnetic material is used. The weak magnetic material may be any of a paramagnetic material and a diamagnetic material. Specific examples of the weak magnetic material include ceramics such as alumina, beryllia, silicon carbide, aluminum nitride, and fluorophlogopite, glass materials such as blue plate glass, flint glass, and Pyrex (registered trademark) glass, copper, aluminum, and tungsten. And a weak magnetic material such as molybdenum.

When the target connection object of the anisotropic conductive sheet is an integrated circuit or the like formed on a wafer, the anisotropic conductive sheet has high dimensional accuracy and a high position of the conductive path forming portion. since precision is required, as the weak magnetic material constituting the substrate 51, 56, it is preferable that a coefficient of linear thermal expansion used as the ^{^{1 X 10- 7 ~1 X 10- 5}} Κ- 1. Examples of such a weak magnetic material, the ceramic, alumina (4. 8 Χ 10- -, beryllium § (4. 3 X 10- ⁶ Κ-, carbide Kei element (3. 7 X 10- ⁶ Κ -, aluminum nitride ^{^{(4. 5 X 10 _6 Κ _1}} ), fluorine phlogopite ^{(8. 0 X 10 "6 Κ} _1), as the glass material, soda lime glass ^{(8 X 10- 6 ~: LO} X 10" 6 kappa ^_1), flint glass ^{(8 X 10- 6 ~9 X 10} "6 Κ _1), Pyrex glass (2. 8 X 10- ⁶ Κ-, as the metal material, tungsten (4. 8 X 10 ^_6 Κ ^_1), molybdenum (5. ⁶ X 10- 6 κ-.

The substrates 51 and 56 preferably have a thickness of 0.1 to 50 mm, have a smooth surface, are chemically degreased, and are mechanically polished. Better.

On the surfaces of the substrates 51 and 56, a single metal film or a plurality of different types of metal films (illustrated in the drawings) can easily form the ferromagnetic layers 52 and 57 by electrolytic plating. (Omitted) is preferably formed.

The material for forming the metal film may be a weak magnetic material or a ferromagnetic material. Specific examples thereof include copper, nickel, cobalt, gold, silver, palladium, rhodium, and platinum. .

As a means for forming a metal film, an electroless plating method can be used. When a ferromagnetic material is used as the material for forming the metal film, the magnetic field From the viewpoint of suppressing the influence, the thickness of the metal film is preferably 30 m or less, more preferably 20 m or less. When the thickness is excessively large, when a magnetic field having a direction of a magnetic flux line opposite to the conductive material layer is applied to the conductive material layer in a method for manufacturing an anisotropic conductive sheet described below, It is not preferable because the 51 and 56 move, which may cause a displacement between the upper mold 50 and the lower mold 55.

The material forming the ferromagnetic layers 52 and 57 in each of the upper mold 50 and the lower mold 55 includes a strong material such as iron, iron-nickel alloy, iron-cobalt alloy, nickel, cono- tant, and nickel-cobalt alloy. Magnetic metals can be used. The ferromagnetic layers 52 and 57 preferably have a thickness force S of 10 μm or more. If the thickness is less than 10 μm, it becomes difficult to apply a magnetic field having a sufficient intensity distribution to the conductive material layer formed in the anisotropic conductive sheet manufacturing mold. As a result, it becomes difficult to aggregate the conductive particles at a high density in a portion of the conductive material layer where the conductive path forming portion is to be formed, so that a sheet having good anisotropic conductivity may not be obtained. .

As a method for forming the ferromagnetic layers 52, 57 on the surfaces of the substrates 51, 56, an electrolytic plating method can be used.

As a material for forming the weak magnetic layers 53 and 58 in each of the upper mold 50 and the lower mold 55, a weak magnetic metal such as copper, a heat-resistant polymer substance, or the like may be used. Able to use a polymer material that is hardened by electromagnetic waves because it is possible to easily form the weak magnetic layers 53 and 58 by a photolithographic method, for example, acrylic Photoresists such as a system dry film resist, an epoxy system liquid resist, and a polyimide system liquid resist can be used.

[0027] Then, using the mold for producing an anisotropic conductive sheet described above,

Forming a conductive material layer in a mold for producing an anisotropic conductive sheet, which contains conductive particles in a liquid polymer forming material which is cured to become an insulating elastic polymer material (a- 1) and by acting on the conductive material layer in the thickness direction of the conductive material layer via the ferromagnetic material layer in the anisotropic conductive sheet production mold, (B-1) a step of assembling conductive particles in a portion to be oriented in the thickness direction of the conductive material layer; Curing the conductive material layer after stopping the action of the magnetic field on the conductive material layer or while continuing the action of the magnetic field (c 1);

Through this, the anisotropic conductive sheet 10 is manufactured.

Hereinafter, each step will be specifically described.

Step (a-1):

In the step (a-1), first, a conductive material is prepared by dispersing conductive particles in a liquid polymer-forming material which is cured to become an insulating elastic polymer material. Various materials can be used as the polymer substance forming material for preparing the conductive material, and specific examples thereof include silicone rubber, polybutadiene rubber, natural rubber, polyisoprene rubber, and styrene-butadiene copolymer. Rubber, conjugated rubbers such as acrylonitrile-butadiene copolymer rubber and hydrogenated products thereof, and block copolymer rubbers such as styrene butagen-gen block copolymer rubber and styrene isoprene block copolymer; Examples of such hydrogenated products include chloroprene rubber, urethane rubber, polyester rubber, epichlorohydrin rubber, ethylene-propylene copolymer rubber, ethylene-propylene copolymer rubber, and soft liquid epoxy rubber. Among these, silicone rubber is preferred from the viewpoints of durability, moldability and electrical properties.

[0029] The silicone rubber is preferably one obtained by crosslinking or condensing a liquid silicone rubber.

The liquid silicone rubber may be any of a condensation type, an addition type, and a compound having a bull group-hydroxyl group. Specific examples include raw dimethyl silicone rubber, raw methyl silicone rubber, raw methyl methyl silicone rubber and the like.

In addition, the addition-type liquid silicone rubber is a one-pack type liquid silicone rubber which is cured by a reaction between a bullet group and a Si—H bond, and is a polysiloxanka containing both a bullet group and a Si—H bond. Both (one-component type) and two-component type (two-component type) having a vinyl group-containing polysiloxane and a Si-H bond-containing polysiloxane can be used. It is preferable to use an addition type liquid silicone rubber of the mold [0030] Of these, the liquid silicone rubber containing a bullet group (polydimethylsiloxane containing a bullet group) is usually prepared by using dimethyldichlorosilane or dimethyldialkoxysilane in the presence of dimethylvinylchlorosilane or dimethylvinylalkoxysilane. In the following, hydrolysis and condensation reactions are performed, for example, followed by fractionation by repeated dissolution and precipitation.

Liquid silicone rubbers containing vinyl groups at both ends are polymerized with a cyclic siloxane such as otatamethylcyclotetrasiloxane in the presence of a catalyst to form a polymerization terminator such as dimethyldibutyl. It can be obtained by using siloxane and appropriately selecting other reaction conditions (for example, the amount of the cyclic siloxane and the amount of the polymerization terminator). Here, as the catalyst for the aone polymerization, alkalis such as tetramethylammonium hydroxide and n-butylphospho-hydroxymide or a silanolate solution thereof can be used. For example, 80 to 130 ° C.

Such a vinyl group-containing polydimethylsiloxane preferably has a molecular weight Mw (referred to as a standard polystyrene-converted weight average molecular weight; the same applies hereinafter) of 10,000 to 40,000. From the viewpoint of the heat resistance of the obtained anisotropic conductive sheet 10, the molecular weight distribution index (refers to the value of the ratio MwZMn between the weight average molecular weight Mw in terms of standard polystyrene and the number average molecular weight Mn in terms of standard polystyrene; the same applies hereinafter). Is preferably 2 or less.

[0031] On the other hand, liquid silicone rubber containing hydroxyl groups (hydroxyl-containing polydimethylsiloxane) is usually prepared by adding dimethyldichlorosilane or dimethyldialkoxysilane to dimethylhydrochlorosilane or dimethylhydroalkoxysilane in the presence of! / It can be obtained by carrying out hydrolysis and condensation reactions, for example, followed by fractionation by repeated dissolution and precipitation.

Further, cyclic siloxane is polymerized in the presence of a catalyst in the presence of a catalyst, and as a polymerization terminator, dimethinolehydrochlorosilane, methinoreshydrochlorosilane or dimethinolehydroalkoxysilane is used 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 the aone polymerization, alkali such as tetramethylammonium hydroxide and η-butylphosphodium hydroxide or a silanolate solution thereof can be used. , Example For example, it is 80 to 130 ° C.

[0032] Such a hydroxyl group-containing polydimethylsiloxane preferably has a molecular weight Mw of 10,000 to 40,000. From the viewpoint of the heat resistance of the obtained anisotropic conductive sheet 10, those having a molecular weight distribution index of 2 or less are preferable.

In the present invention, either one of the above-mentioned polydimethylsiloxane containing a butyl group and polydimethylsiloxane containing a hydroxyl group can be used, or both are used in combination.

When producing an anisotropic conductive sheet 10 used for a probe test or a burn-in test of a circuit device, for example, as a liquid silicone rubber, the cured product thereof has a compression set of 10% at 150 ° C. It is more preferable to use the following, more preferably 8% or less, and further preferably 6% or less. If the compression set exceeds 10%, the conductive path forming portion 11 is permanently set when the obtained anisotropic conductive sheet 10 is used repeatedly many times or repeatedly in a high temperature environment. Immediately after the distortion occurs, the chain of the conductive particles in the conductive path forming portion 11 is disturbed, so that it may be difficult to maintain the required conductivity.

Here, the compression set of the cured product of the liquid silicone rubber can be measured by a method based on JIS K 6249.

[0034] The liquid silicone rubber preferably has a durometer A hardness of 10 to 60 at 23 ° C, more preferably 15 to 60, particularly preferably 20 to 60. Things. If the durometer A hardness is less than 10, the insulating part 12 that insulates the conductive path forming parts 11 from each other when pressurized may be excessively deformed or may have a required insulation property between the conductive path forming parts 11. May be difficult to maintain. On the other hand, if the durometer A hardness exceeds 60, a considerably large load is required to apply an appropriate strain to the conductive path forming portion 11, so that, for example, deformation or breakage of the inspection object may occur. It is easy to occur.

Here, the durometer A hardness of the cured liquid silicone rubber can be measured by a method based on JIS K 6249.

The liquid silicone rubber has a cured product having a tear strength at 23 ° C. of 8 k. It is preferable to use one having NZm or more, more preferably at least 10 kN / m, more preferably at least 15 kN / m, particularly preferably at least 20 kN / m. When the tear strength is less than 8 kNZm, the durability is likely to decrease when the anisotropic conductive sheet 10 is subjected to excessive strain.

Here, the tear strength of the cured product of the liquid silicone rubber can be measured by a method based on JIS K 6249.

As the liquid silicone rubber, it is preferable to use a liquid silicone rubber having a viscosity at 23 ° C. of 100 to 1,250 Pa ′s, more preferably 150 to 800 Pa ′s, and particularly preferably 250 to 500 Pa ′s. s. When the viscosity is less than 100 Pa's, the resulting conductive material is liable to cause sedimentation of the conductive particles in the liquid silicone rubber, failing to obtain good storage stability, and a process described below. In (b-1), when a magnetic field is applied to the conductive material layer in the thickness direction, the conductive particles are not aligned so as to be aligned in the thickness direction, and form a chain of conductive particles in a uniform state. It can be difficult. On the other hand, if the viscosity exceeds 1,250 Pa's, the resulting conductive material has a high viscosity, so that it is difficult to form a conductive material layer in the anisotropic conductive sheet manufacturing mold. In addition, even when a magnetic field is applied to the conductive material layer in the thickness direction, the conductive particles do not move sufficiently, and therefore, the conductive particles may be oriented to be aligned in the thickness direction. It can be difficult.

Here, the viscosity of the liquid silicone rubber can be measured by a B-type viscometer.

[0037] The polymer substance-forming material may contain a curing catalyst for curing the polymer substance-forming material. As such a curing catalyst, an organic peroxide, a fatty acid azoide compound, a hydrosilylide 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 azobisisobutyl nitrile.

Specific examples of those which can be used as a catalyst for the hydrosilylation reaction include chloroplatinic acid and And its salts, siloxane complex containing platinum unsaturated group, complex of butylsiloxane and platinum, complex of platinum and 1,3 dibutyltetramethyldisiloxane, complex of triorganophosphine or phosphite and platinum, acetylacetate platinum Known ones such as a chelate and a complex of a cyclic gen and platinum are exemplified.

The amount of the curing catalyst used is appropriately selected in consideration of the type of the polymer-forming material, the type of the curing catalyst, and other curing conditions. 15 parts by weight.

[0038] The polymer substance forming material may be a material containing an inorganic filler such as ordinary silica powder, colloidal silica, air-port gel silica, and alumina. By containing such an inorganic filler, the thixotropic property of the obtained conductive material is secured, the viscosity thereof is increased, and the dispersion stability of the conductive particles P is improved, and the conductive material P is cured. The strength of the obtained anisotropic conductive sheet 10 increases.

The use amount of such an inorganic filler is not particularly limited. However, when used in a large amount, the movement of the conductive particles P due to the magnetic field in the step (b-1) described later is greatly inhibited. Therefore, it is not preferable.

As the conductive particles for preparing the conductive material, those exhibiting magnetism are used, and specific examples thereof include particles of a metal exhibiting magnetism such as iron, nickel, and cobalt or alloys thereof. Particles or particles containing these metals, or those particles as core particles, and the surface of the core particles is subjected to plating of a metal having good conductivity such as gold, silver, nordium, rhodium, In some cases, inorganic particles or polymer particles such as weak magnetic metal particles or glass beads are used as core particles, and the surface of the core particles is coated with a conductive magnetic material such as nickel or cobalt. And those coated with both a conductive magnetic material and a metal having good conductivity.

Among them, it is preferable to use nickel particles as core particles, the surfaces of which are 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, an electroless plating. [0040] 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 The ratio of the conductive metal coating area to the particle surface area) is preferably 40% or more, more preferably 45% or more, and particularly preferably 47 to 95%.

The coating amount of the conductive metal is preferably 2.5 to 50% by weight of the core particles, more preferably 3 to 30% by weight, still more preferably 3.5 to 25% by weight, and particularly preferably. Is from 4 to 20% by weight. When the conductive metal to be coated is gold, the coating amount is preferably 3 to 30% by weight of the core particles, more preferably 3.5 to 25% by weight, still more preferably 4 to 25% by weight. 20% by weight. When the conductive metal to be coated is silver, the coating amount is preferably 3 to 30% by weight of the core particles, more preferably 4 to 25% by weight, and even more preferably 5 to 25% by weight. -23% by weight, particularly preferably 6-20% by weight.

The particle diameter of the conductive particles is preferably 1 to 500 μm, more preferably 2 to 300 m, further preferably 3 to 200 m, particularly preferably 5 to 500 μm. 150 m. The particle size distribution (DwZDn) of the conductive particles is preferably from 1 to LO, more preferably from 1 to 7, further preferably from 1 to 5, and particularly preferably from 1 to 4.

By using the conductive particles satisfying such conditions, the obtained anisotropic conductive sheet 10 can be easily deformed under pressure, and the conductive path forming portion 11 in the anisotropic conductive sheet 10 can be obtained. In addition, sufficient electrical contact between the conductive particles P can be obtained.

Further, the shape of the conductive particles is not particularly limited, but is spherical, star-shaped, or agglomerated because they can be easily dispersed in the polymer-forming material. It is preferably a lump formed by secondary particles.

[0042] The water content of the conductive particles is preferably 5% or less, more preferably 3% or less, further preferably 2% or less, and particularly preferably 1% or less. By using the conductive particles satisfying such conditions, it is possible to prevent or prevent air bubbles from being generated in the conductive material layer when the conductive material layer is cured in the step (c-1) described later. It is suppressed.

One of the molding surface of the upper mold 50 and the molding surface of the lower mold 55 in the mold for producing an anisotropic conductive sheet shown in FIG. Alternatively, as shown in FIG. 4, the upper mold 50 coated with the conductive material is superimposed on the lower mold 55 coated with the conductive material via the frame plate 15 as shown in FIG. In the cavity between the upper mold 50 and the lower mold 55 in the mold for producing an anisotropic conductive sheet, a conductive material layer 10A containing the conductive particles P in the polymer-forming material is formed. In the conductive material layer 10A, as shown in FIG. 5, the conductive particles P are in a state of being dispersed in the conductive material layer 10A.

As described above, various materials such as a metal material, a ceramic material, and a resin material can be used as a material of the frame plate 15, and specific examples thereof include iron, copper, and −. Metal materials such as nickel, chromium, conoort, magnesium, manganese, molybdenum, indium, lead, palladium, titanium, tungsten, aluminum, gold, platinum, silver, and alloys or alloy steels combining two or more of these. Ceramic materials such as silicon nitride, silicon carbide, and alumina, aramide resin, aramide nonwoven reinforced epoxy resin, aramide nonwoven reinforced polyimide resin, aramide nonwoven reinforced bismaleimide triazine resin, etc. Fatty materials.

When the anisotropic conductive sheet 10 used for the burn-in test is manufactured, the material constituting the frame plate 15 has a linear thermal expansion coefficient of the linear thermal expansion coefficient of the material constituting the wafer to be inspected. It is preferable to use one that is equivalent or approximate to the expansion coefficient. Specifically, when the material constituting the wafer is silicon, a coefficient of linear thermal expansion 1. 5 X 10 ZK less, in particular, be used as a ^{^{3 X 10- 6 ~8 X 10- 6}} Ζκ Specific examples that are preferred are Invar-type alloys such as Invar, Elinvar-type alloys such as Elinvar, metal materials such as Super Invar, Kovar, 42 alloy, and non-woven fabric-reinforced organic resin materials such as Aramide. No.

The thickness of the frame plate 15 is, for example, 0.02 to Lmm, and preferably 0.05 to 0.25 mm.

Step (b-l):

In the step (b-l), the conductive material layer 10A formed in the step (a-l) is connected to the conductive material layer 10A via the ferromagnetic layers 52 and 57 in the anisotropic conductive sheet manufacturing mold. By acting in the thickness direction of the conductive material layer 10A, the conductive material layer 10A is guided to the conductive path forming portion. The conductive particles are aggregated and oriented so as to be arranged in the thickness direction of the conductive material layer 10A. More specifically, as shown in FIG. 6, an electromagnet device 60 having an upper electromagnet 61 and a lower electromagnet 65 and having the magnetic poles 62 and 66 opposed to each other is prepared. Between the magnetic pole 62 of the upper electromagnet 61 and the magnetic pole 66 of the lower electromagnet 65 in the device 60, a mold for producing an anisotropic conductive sheet having a conductive material layer 10A formed in a cavity is arranged. Next, by operating the electromagnet device 60, the weak magnetic layer 53 of the upper die 50 is placed between the ferromagnetic layer 52 of the upper die 50 and the corresponding ferromagnetic layer 57 of the lower die 55. A stronger magnetic field is formed between the lower mold 55 and the weak magnetic layer 58 of the lower mold 55. In other words, a magnetic field having a greater intensity is applied to the conductive material layer 10A on the portion to be the conductive path forming portion, and thereby the conductive particles dispersed in the conductive material layer 10A are formed. P is collected in a portion to be a conductive path forming portion and is oriented so as to be arranged in the thickness direction of the conductive material layer 10A.

Here, it is preferable that the intensity of the magnetic field applied to the conductive material layer 10A has a magnitude of 0.02 to 2.5 Tesla on average.

This step (b-1) is preferably performed under conditions that do not promote the curing of the conductive material layer 10A, for example, at room temperature.

Then, in this step (b-1), the operation of the magnetic field on the conductive material layer 10A is temporarily stopped, and thereafter, the operation of applying the magnetic field on the conductive material layer 10A again (hereinafter, this operation is referred to as the operation). "Re-operating operation") is performed at least once. Specifically, this restarting operation is performed by stopping the operation of the electromagnet device 60 and then activating the electromagnet device 60 again.

In response to this restarting operation, the time from when the magnetic field is stopped applied to the conductive material layer 10A until when the magnetic field is applied again to the conductive material layer 10A (hereinafter referred to as “operation stop time”) ) Is appropriately set in consideration of the viscosity of the conductive material layer 10A, the ratio of the conductive particles in the conductive material layer 10A, the average particle size of the conductive particles, and the like, but may be 200 seconds or less. It is more preferably 60 seconds or less.

If the operation stop time is excessively long, the time required for the process (b-1) becomes too long, so that the production efficiency throughout the entire production process becomes extremely low and the liquid Since the curing of the secondary material forming material starts, the viscosity of the conductive material layer 10A changes, so that a sufficient effect may not be obtained.

[0047] In the restarting operation, the magnetic field applied to the conductive material layer 10A again has the same direction as that of the magnetic field before the stop. May be in the direction opposite to the direction of the magnetic flux lines of the magnetic field before the stop, but may be in the direction opposite to the direction of the magnetic flux lines of the magnetic field before the stop in that the effect of the residual magnetic field is small. preferable.

When a magnetic field whose direction of the magnetic flux lines is opposite to that of the magnetic field before the stop is applied, the strength of the magnetic field is preferably substantially equal to the strength of the magnetic field before the stop.

In order to apply a magnetic field in which the direction of the magnetic flux lines is opposite to the direction of the magnetic flux lines of the magnetic field before stopping, the polarity of the magnetic poles 62 of the upper electromagnet 61 and the magnetic poles 66 of the lower electromagnet 65 in the electromagnet device 60 must be adjusted. Change the polarity!

Specifically, when a magnetic field is first applied to the conductive material layer 10A, for example, under the condition that the magnetic pole 62 of the upper electromagnet 61 is the N pole and the magnetic pole 66 of the lower electromagnet 65 is the S pole, Activate the electromagnet device 60. In this state, since the ferromagnetic layer 52 of the upper mold 50 functions as the N pole and the ferromagnetic layer 57 of the lower mold 55 functions as the S pole, as shown in FIG. The direction of the magnetic flux lines in the acting magnetic field is the direction from the ferromagnetic layer 52 of the upper die 50 to the corresponding ferromagnetic layer 57 of the lower die 55, that is, from the top to the bottom. In this way, the operation of the electromagnet device 60 is temporarily stopped after a predetermined time has elapsed while the magnetic field is applied to the conductive material layer 10A. Thereafter, the electromagnet device 60 is operated again under the condition that the magnetic pole 62 of the upper electromagnet 61 becomes the S pole and the magnetic pole 66 of the lower electromagnet 65 becomes the N pole. In this state, the ferromagnetic layer 52 of the upper mold 50 functions as the S pole and the ferromagnetic layer 57 of the lower mold 55 functions as the N pole, so that it acts on the conductive material layer 10A as shown in FIG. The direction of the magnetic flux lines in the applied magnetic field is the direction from the ferromagnetic layer 57 of the lower die 55 to the corresponding ferromagnetic layer 52 of the upper die 50, that is, the direction of the upward force from below. According to such a method, when the operation of the electromagnet device 60 is stopped, even if a residual magnetic field is generated, it is demagnetized by operating the electromagnet device 60 again, so that the influence of the residual magnetic field is reduced.

[0048] The restarting operation may be performed at least once in step (b-1). Specifically, it is preferable that the operation is performed repeatedly. More preferably, the number of restart operations is 5 or more, more preferably 10 to 500 times.

If the number of restart operations is too small, there is little opportunity for the individual conductive particles P in the conductive material layer 10A to be released by the binding force of the magnetic force, and therefore, the movement of the conductive particles P again occurs. Since there is little opportunity to start, the chain of the conductive particles P is less likely to be formed in a direction more faithful to the thickness direction of the conductive material layer 10A, and as a result, the resulting anisotropic conductive sheet has a small thickness. Therefore, it may be difficult to reliably prevent the formation of the chain of the conductive particles P that connects the adjacent conductive path forming portions.

[0049] As described above, when the restart operation is repeatedly performed, the magnetic field is again applied to the conductive material layer, and then the operation of the magnetic field to the conductive material layer is stopped. (Hereinafter referred to as “reactivation time”) is appropriately determined in consideration of the viscosity of the conductive material layer 10A, the ratio of the conductive particles in the conductive material layer 10A, the average particle size of the conductive particles, and the like. The set force is preferably from 10 to 300 seconds, more preferably from 10 to 200 seconds. If the reactivation time is too short, a high-intensity magnetic field is not formed, so that the conductive particles P in the conductive material layer 10A do not move sufficiently, and as a result, the conductive material layer 10A In some cases, it is difficult to form a chain of the conductive particles P in a direction more faithful to the thickness direction. On the other hand, if the reactivation time is too long, the time required for the step (b-1) becomes too long, and the production efficiency throughout the entire production process becomes extremely low. As the curing of the conductive material starts, the viscosity of the conductive material layer 10A changes, so that a sufficient effect may not be obtained.

As described above, in step (bl), as shown in FIG. 9, the ferromagnetic layer 52 of the upper die 50 and the ferromagnetic layer 57 of the lower die 55 corresponding thereto are formed. A conductive material layer 10A densely contained with conductive particles P oriented in the thickness direction is formed in a portion therebetween, that is, a portion serving as a conductive path forming portion.

[0051] Step (c1):

In the step (cl), a hardening treatment is performed on the conductive material layer 10A in which the conductive particles P are densely contained in a portion to be the conductive path forming portion in a state of being oriented in the thickness direction. The curing treatment of the conductive material layer 10A reduces the action of the magnetic field on the conductive material layer 10A. It may be performed after stopping, or may be performed while applying a magnetic field to the conductive material layer 10A, but is preferably performed while applying a magnetic field.

The curing treatment of the conductive material layer 10A is usually performed by a heat treatment which varies depending on the material used. The specific heating temperature and heating time are appropriately set in consideration of the type of the polymer substance forming material constituting the conductive material layer 1OA.

After the curing process of the conductive material layer 10A is completed, the anisotropic conductive sheet 10 shown in FIG. 1 and FIG. can get.

According to the above-described mold for producing an anisotropic conductive sheet and the method for producing an anisotropic conductive sheet, the following effects can be obtained.

That is, since the substrate 51 of the upper mold 50 and the substrate 56 of the lower mold 55 are each made of a weak magnetic material, when a magnetic field is applied to the conductive material layer 10A, the conductive material layer Since the strength of the magnetic field acting on the insulating portion at 10A can be sufficiently reduced, the conductive particles P present in the insulating portion surely gather in the conductive path forming portion. As a result, it is possible to form the insulating portion 12 having no or almost no conductive particles P, and to form the conductive path forming portion 11 containing a required amount of the conductive particles P. . Therefore, even if the pitch of the conductive path forming portions 11 to be formed is small, the conductive path forming portions 11 having the desired conductivity are provided, and the required insulating property between the adjacent conductive path forming portions 11 is maintained. An anisotropic conductive sheet 10 that can be reliably obtained can be manufactured.

In addition, by using a material having a specific coefficient of linear thermal expansion in a specific range as a material for forming the substrates 51 and 56, the substrate 51 and 56 can be subjected to heat treatment for curing the conductive material layer 1OA. , 56, the anisotropic conductive sheet having high dimensional accuracy of the entire sheet and high positional accuracy of the conductive path forming portion can be manufactured.

Further, since the action of the magnetic field on the conductive material layer 10A is temporarily stopped, in this stopped state, the individual conductive particles P in the conductive material layer 10A are released from the restraint by the magnetic force. Then, by applying a magnetic field again to the conductive material layer 10A in the thickness direction, this operation was triggered, and the movement of the conductive particles P was started again. Therefore, a chain of the conductive particles P is formed in a direction more faithful to the thickness direction of the conductive material layer 10A.

In this way, the formation of chains of conductive particles P in a direction inclined with respect to the thickness direction can be suppressed, so that even when pressed with a small pressing force, the electric resistance value is low and stable. Since the conductive particles P exhibit high conductivity and prevent the formation of a chain of conductive particles P that connects adjacent conductive path forming portions, the pitch of the conductive path forming portions 11 is small. In addition, it is possible to manufacture the anisotropic conductive sheet 10 that ensures the required insulation between the adjacent conductive path forming portions 11.

Further, even when a magnetic field whose direction of the magnetic flux lines is opposite to that of the conductive material layer 10A is applied, the magnetic force prevents the substrate 51 of the upper die 50 and the substrate 56 of the lower die 55 from moving. Therefore, since there is no displacement between the upper mold 50 and the lower mold 55, the conductive path forming portion 11 extending in the direction faithful to the thickness direction can be formed. The anisotropic conductive sheet 10 having the conductive path forming portion 11 exhibiting the above-mentioned conductivity can be manufactured. Further, since air is prevented from entering the mold for producing an anisotropic conductive sheet, it is possible to suppress the occurrence of defective products due to bubbles.

Example

Hereinafter, the ability to explain specific examples of the present invention is not limited thereto.

(1) Production of mold for producing anisotropic conductive sheet:

According to the configuration shown in FIG. 3, a mold for producing an anisotropic conductive sheet having the following specifications was produced. The upper mold (50) and the lower mold (55) are coated on the surface of a substrate material made of fluorophlogopite with a thickness of 6 mm, and a nickel film with a thickness of 3 μm and a copper film with a thickness of 5 μm, Each substrate (51, 56) has 2,000 rectangular ferromagnetic layers (52, 57) made of nickel-cobalt on the surface of each substrate (51, 56). Formed by! / The dimensions of each of the ferromagnetic layers (52, 57) are 40 m (length) × 100 m (width) × 5 O / zm (thickness), and the arrangement pitch is 80 m. The dry film resist is hardened in areas other than the ferromagnetic layers (52, 57) on the surface of the substrate (51, 56). The processed weak magnetic layer (53, 58) is formed. The thickness of the portion where the cavity recesses (53a, 58a) are formed in the weak magnetic layer (53, 58) is 80 μm, and the thickness of the other portions is 90 μm.

(2) Production of frame plate:

A frame plate having the following specifications was produced.

The frame plate is made of S42 alloy material and has a rectangular shape of S250mm X 250mm X O. 03mm with dimensional force of 100mm. It is formed as follows.

[0057] (3) Step (a-1):

A conductive material was prepared by adding and mixing 140 parts by weight of conductive particles having an average particle diameter of 8.7 m to 100 parts by weight of an addition-type liquid silicone rubber, followed by defoaming under reduced pressure. .

This conductive material is applied to the upper mold surface and the lower mold surface of the above-described anisotropic conductive sheet manufacturing mold by a screen printing method, and then the lower plate, the frame plate and the upper mold are placed on the lower mold. By overlapping in this order, a conductive material layer was formed in the cavity between the upper mold and the lower mold.

In the above, nickel particles were used as the core particles, and the core particles were subjected to electroless gold plating (average coating amount: 25% by weight of the core particles).

The addition-type liquid silicone rubber is a two-part type having a viscosity of liquid A of 250 Pa's and a viscosity of liquid B of 250 Pa's. 5%, the durometer A hardness of the cured product was 35, and the tear strength of the cured product was 25 kNZm.

[0058] The properties of the above-mentioned addition type liquid silicone rubber and its cured product were measured as follows.

(i) Viscosity of addition type liquid silicone rubber:

The viscosity at 23 ± 2 ° C was measured by a B-type viscometer.

(ii) Compression set of silicone rubber cured product: The liquid A and the liquid B in the two-part addition-type liquid silicone rubber were stirred and mixed at an equal ratio. Next, the mixture is poured into a mold for producing an anisotropic conductive sheet, the mixture is subjected to a defoaming treatment under reduced pressure, and a curing treatment is performed at 120 ° C. for 30 minutes to obtain a thickness. Was made of a silicone rubber cured product having a diameter of 12.7 mm and a diameter of 29 mm, and was post-cured at 200 ° C. for 4 hours. Using the thus obtained cylinder as a test piece, compression set at 150 ± 2 ° C was measured in accordance with JIS K 6249.

(iii) Tear strength of cured silicone rubber:

By subjecting the addition type liquid silicone rubber to curing treatment and post-curing under the same conditions as in (ii) above, a sheet having a thickness of 2.5 mm was produced. A turret-shaped test piece was prepared from this sheet by punching, and the tear strength at 23 ± 2 ° C was measured in accordance with JIS K 6249.

(iv) Durometer A hardness:

Five sheets prepared in the same manner as in (iii) above are stacked, and the obtained stack is used as a test piece.The durometer A hardness at 23 ± 2 ° C is measured in accordance with JIS K 6249, and 7 sheets are measured. .

(4) Step (b-1):

An electromagnet device having an upper electromagnet and a lower electromagnet, and arranged such that their magnetic poles face each other, is provided between the magnetic pole of the upper electromagnet and the magnetic pole of the lower electromagnet in the electromagnet device. A mold for manufacturing an anisotropic conductive sheet on which a conductive material layer was formed was set. Next, by operating the electromagnet device at room temperature for 15 seconds, a magnetic field of 1.6 T was applied to the portion of the conductive material layer to be the conductive path forming portion, and a re-operation was performed for a total of 200 times. A magnetic field was applied to the portion to be the conductive path forming portion while performing the process. Here, the conditions for the restart operation are as follows: the operation stop time is 5 seconds, the restart time is 15 seconds, the direction of the magnetic flux lines of the magnetic field applied again is opposite to the direction of the magnetic flux lines before the stop, Again, when a magnetic field is applied to the portion of the conductive material layer that becomes the conductive path forming portion, the strength of the magnetic field is 1.6 T in each case.

[0060] (5) Step (c1): By operating the electromagnet device with the anisotropic conductive sheet manufacturing mold set between the magnetic pole of the upper electromagnet and the magnetic pole of the lower electromagnet in the electromagnet device,

Then, while applying a magnetic field having a strength of 1.6 T to the portion of the conductive material layer that will become the conductive path forming portion, the conductive material is cured at 100 ° C for 2 hours, and then room temperature is applied. After cooling, the anisotropic conductive sheet manufacturing die was taken out to produce an anisotropic conductive sheet in which a frame plate was integrally provided on the periphery of the insulating part.

In the obtained anisotropic conductive sheet, 2,000 rectangular conductive path forming parts are arranged at a pitch of 80 m, and the conductive path forming part has a vertical and horizontal dimensional force of 0 mx 100 m and a thickness of 100 m. The projecting height from both sides of the insulating portion was 110 / ζπι, and the thickness of the insulating portion was 50 / zm, respectively.

Further, when the content ratio of the conductive particles in the conductive path forming portion was examined, the volume fraction was about 30% in all the conductive path forming portions.

According to the configuration shown in FIG. 3, a mold for producing an anisotropic conductive sheet having the following specifications was produced. The upper mold (50) and the lower mold (55) are each formed of a 0-thick film formed by sputtering on a surface of a substrate material made of Pyrex (registered trademark) glass having a thickness of 6 mm. Has a substrate (51, 56) in which a 5 m copper film is laminated in this order. On the surface of each substrate (51, 56), there are 2,000 rectangular ferromagnetic materials made of nickel-cobalt, respectively. The layers (52, 57) are formed by electrolytic plating. The dimensions of each of the ferromagnetic layers (52, 57) are 40 / z m (length) X 100 / z m (width) Χ 50 / ζ πι (thickness), and the arrangement pitch is 80 m. In regions other than the ferromagnetic layers (52, 57) on the surface of the substrate (51, 56), weak magnetic layers (53, 58) obtained by hardening a dry film resist are provided. Is formed. The thickness of the portion where the cavity recesses (53a, 58a) are formed in the weak magnetic layer (53, 58) is 80 μm, and the thickness of the other portions is 90 μm. An anisotropic conductive sheet was produced in the same manner as in Example 1, except that this mold for producing an anisotropic conductive sheet was used.

In the obtained anisotropic conductive sheet, 2,000 rectangular conductive path forming parts are arranged at a pitch of 80 m, and the conductive path forming part has a vertical and horizontal dimensional force of 0 mx 100 m, a thickness of 100 m. The thickness of the insulating part was 30 / zm, the height of the protrusion from both sides of the insulating part was 30 / zm, and the thickness of the insulating part was 50 / zm.

According to the configuration shown in FIG. 3, a mold for producing an anisotropic conductive sheet having the following specifications was produced. The upper mold (50) and the lower mold (55) are formed by sputtering a nickel film with a thickness of 0.5 m and a copper film with a thickness of 5 / zm on the surface of a substrate material made of molybdenum with a thickness of 6 mm. Have substrates (51, 56) laminated in this order, and on the surface of each substrate (51, 56), 2,000 rectangular ferromagnetic layers (52, 56) made of nickel-cobalt, respectively. 5 7) is formed by electrolytic plating. The dimensions of each of the ferromagnetic layers (52, 57) are 40 m (length) × 100 m (width) × 50 m (thickness), and the arrangement pitch is 80 μm. On the surface of the substrate (51, 56) other than where the ferromagnetic layer (52, 57) is formed, a weak magnetic layer (53, 58) obtained by hardening a dry film resist is provided. Is formed. The thickness of the portion where the cavity recesses (53a, 58a) are formed in the weak magnetic layer (53, 58) is 80 μm, and the thickness of the other portions is 90 μm. An anisotropic conductive sheet was produced in the same manner as in Example 1 except that this mold for producing an anisotropic conductive sheet was used.

A mold for producing an anisotropic conductive sheet having the same specifications as in Example 1 was prepared except that a substrate made of ferromagnetic material 42 alloy was used, and this mold for producing an anisotropic conductive sheet was used. Except for this, an anisotropic conductive sheet was produced in the same manner as in Example 1.

In the obtained anisotropic conductive sheet, 2000 rectangular conductive path forming portions are 80 m The conductive path forming part has a vertical and horizontal dimensional force of 0 mx 100 m, a thickness of 110 / ζπι, and a protrusion height from both sides of the insulating part of 30 m each. Was 50 / zm thick.

[Evaluation of Anisotropic Conductive Sheet]

The following evaluations were performed on the anisotropic conductive sheets obtained in Examples 1 to 3 and Comparative Example 1.

Conductivity of conductive path forming part:

In a state where all the conductive path forming portions of the anisotropic conductive sheet were pressed so that the strain rate in the thickness direction became 20%, the electrical resistance value in the thickness direction of each of the conductive path forming portions was measured. . The results are shown in Table 1.

Insulation between conductive path forming parts:

In a state where all the conductive path forming portions of the anisotropic conductive sheet are pressed so that the strain rate in the thickness direction is 20%, the electric resistance value between the adjacent conductive path forming portions is measured, and the value is measured. Numbers less than 1 ΜΩ were determined. The results are shown in Table 1.

[0065] [Table 1]

As is evident from the results in Table 1, according to Examples 1 to 3, even when pressurized with a small pressing force, the conductive path forming portion has a low electric resistance value and exhibits stable conductivity. And all that It was confirmed that an anisotropic conductive sheet having a required insulating property with respect to the adjacent conductive path forming portion can be obtained with respect to the conductive path forming portion. On the other hand, the anisotropic conductive sheet obtained in Comparative Example 1 has a small electrical resistance value with respect to a part of the conductive path forming part and an adjacent conductive path forming part. The difference between the anisotropically conductive sheets obtained in Examples 1 to 3 and the anisotropically conductive sheet obtained in Comparative Example 1 is obvious.

Claims

The scope of the claims

[1] A plurality of conductive path forming portions including conductive particles exhibiting magnetism in an insulating elastic polymer material in a state of being oriented in a thickness direction, and insulating the conductive path forming portions from each other. A mold for manufacturing an anisotropic conductive sheet for manufacturing an anisotropic conductive sheet having an insulating portion made of an insulating elastic polymer material.

A substrate and a ferromagnetic layer disposed on the substrate according to a pattern corresponding to the pattern of the conductive path forming portion,

The mold for producing an anisotropic conductive sheet, wherein the substrate is made of a weak magnetic material.

[2] A conductive material layer in which conductive particles are contained in a liquid polymer forming material which is cured to become an insulating elastic polymer material is formed in a mold for producing an anisotropic conductive sheet; By applying a magnetic field to the conductive material layer in the thickness direction of the conductive material layer via the ferromagnetic layer in the anisotropic conductive sheet manufacturing mold, the conductive path forming portion is formed. A step of assembling the conductive particles in the portion and orienting the conductive particles in the thickness direction of the conductive material layer. In this step, after stopping the action of the magnetic field on the conductive material layer, the conductive 2. The mold for producing an anisotropic conductive sheet according to claim 1, wherein the mold is used in a method for producing an anisotropic conductive sheet in which an operation of applying a magnetic field to a material layer is performed at least once.

[3] The substrate, anisotropic conductive according to claim 1 or claim 2, wherein the coefficient of linear thermal expansion is made of a weak magnetic material ^{^{1 X 10- 7 ~1 X 10- 5}} K _1 Mold for sheet production.

4. The mold for producing an anisotropic conductive sheet according to claim 1, wherein a metal film is formed on a surface of the substrate.

[5] A plurality of conductive path forming portions in which conductive particles exhibiting magnetism are contained in an insulating elastic polymer material in a state oriented in the thickness direction, and these conductive path forming portions are insulated from each other. A method for producing an anisotropic conductive sheet having an insulating portion made of an insulating elastic polymer material,

The mold for producing an anisotropic conductive sheet according to any one of claims 1 to 4, which is cured into an insulating elastic polymer material in the mold for producing an anisotropic conductive sheet. Forming a conductive material layer containing conductive particles in the polymer forming material of By applying a magnetic field to the conductive material layer in the thickness direction of the conductive material layer via the ferromagnetic layer in the anisotropic conductive sheet manufacturing mold, a portion serving as the conductive path forming portion is formed. A process of assembling conductive particles and orienting them in the thickness direction of the conductive material layer,

In this step, after the action of the magnetic field on the conductive material layer is stopped, an operation of applying the magnetic field to the conductive material layer is performed at least once again. Method.

[6] After stopping the action of the magnetic field on the conductive material layer, in the operation of applying the magnetic field again to the conductive material layer, the direction of the magnetic flux lines of the magnetic field applied again on the conductive material layer is stopped. 6. The method for producing an anisotropic conductive sheet according to claim 5, wherein the direction is opposite to the direction of the magnetic flux lines of the previous magnetic field.

[7] The method according to claim 5 or 6, wherein the operation of applying the magnetic field to the conductive material layer is repeated after stopping the action of the magnetic field on the conductive material layer. A method for producing an anisotropic conductive sheet.

[8] The anisotropic conductive material according to claim 7, wherein after stopping the action of the magnetic field on the conductive material layer, the operation of applying the magnetic field to the conductive material layer is performed five times or more again. Method for producing a functional sheet.