JP2003155360A - Silicone rubber sheet for thermocompression bonding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silicone rubber sheet for thermocompression bonding, capable of improving the working property of the compression bonding without sticking a sheet on a compression tool or compression bonded material, also having a good endurance of the sheet itself and hardly polluting surroundings. SOLUTION: This silicone rubber sheet for the thermocompression bonding is characterized by having unevenness of 0.8-5 μm arithmetically averaged surface coarseness on at least one of its surfaces.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermocompression-bonding silicone rubber sheet which is interposed between an object to be pressure-bonded and a thermocompression-bonding device when the object to be pressure-bonded is thermocompression bonded, and in particular, is excellent in releasability and has a peripheral shape. The present invention relates to a silicone rubber sheet for thermocompression bonding, which does not easily contaminate the device parts and the object to be pressure bonded.

[0002]

2. Description of the Related Art In recent years, liquid crystal panels have been increasingly used as displays for portable computers, word processors, video cameras, navigation systems, portable televisions and the like. In order to drive the liquid crystal, the electrodes connected to the liquid crystal panel and the lead electrodes of the flexible printed circuit board (FPC) on which the driving LSI is mounted are thermocompression-bonded with an anisotropic conductive adhesive interposed between them, and electrical Need to be mechanically and mechanically connected. At this time, pressurizing tool and FPC
A sheet for thermocompression bonding is used for the purpose of applying uniform pressure while transmitting heat from the pressure tool to the anisotropic conductive adhesive by sandwiching it between the sheets. As such a sheet for thermocompression bonding,
A fluororesin film such as polytetrafluoroethylene (PTFE) may be used, but it is common to use a silicone rubber sheet having low elasticity, flexibility and good thermal conductivity in order to apply pressure evenly. It has become.

However, the silicone rubber sheet is more sticky on the sheet surface than the fluororesin film,
Since the sheet adheres to the pressure tool or the FPC in close contact with it, not only the workability in the pressure bonding step is significantly deteriorated, but also the sheet may deteriorate when peeled off, resulting in poor durability. Therefore, as a silicone rubber sheet for thermocompression bonding, for example, boron nitride is blended with silicone rubber to improve thermal conductivity and to be reinforced with a glass cloth (Japanese Patent Laid-Open No. HEI5-
(198344), boron nitride and a conductive substance are mixed with silicone rubber, and further reinforced with glass cloth to impart antistatic property (JP-A-6-36853).
Heat resistant by blending silicone rubber with a good thermal conductive material such as ceramic or metal (JP-A-6-289352), or blending silicone rubber with carbon black whose volatile content other than water is 0.5% or less. Although improved properties (Japanese Patent Application Laid-Open No. 7-11010) and the like have been proposed, the tackiness of the sheet surface has not been improved yet.

To solve the problem of tackiness of the surface of the sheet, there is a method of reducing the tackiness of the sheet by evenly dusting flaky powder such as talc or mica on the surface of the silicone rubber sheet, or by dusting. Therefore, a method of removing excess powder by washing with water has been proposed. or,
There has been proposed a silicone rubber composite sheet for thermocompression bonding which is excellent in strength while eliminating the tackiness of the sheet surface by compounding a silicone rubber sheet and a heat resistant resin film (JP-A-8-174765). However,
Since this sheet has silicone rubber adhered to the heat-resistant resin film, it has a drawback that it is less flexible than the case where only rubber is used. This tendency becomes particularly strong when heat-resistant resin films are provided on both sides of the sheet. When the flexibility is lost in this way, it becomes difficult to apply pressure uniformly during pressurization, so it is necessary to increase the pressing force, but there is a limit in relation to the strength of the pressure-bonded body. Such a defect is ameliorated by using a rubber having a low hardness to improve the flexibility, but in order to reduce the hardness of the rubber as described above, it is necessary to reduce the carbon filling amount, and therefore the thermal conductivity is reduced. There is a drawback that the property becomes poor. Also, since it is difficult to clean the liquid crystal panel after mounting the FPC, considering that it is important not to stain the process,
None of the conventional methods is perfect, and there has been a demand for the development of a silicone rubber sheet that is free from the risk of contaminating surrounding device parts and pressure-bonded objects.

[0005]

Therefore, the present inventors
As a result of diligent study on a silicone rubber sheet for thermocompression bonding, which has excellent surface releasability and does not easily contaminate surrounding equipment parts and objects to be pressure-bonded, as a result, at least one surface of the silicone rubber sheet has irregularities within a certain range. The inventors have found that good results can be obtained according to the present invention and arrived at the present invention. Therefore, an object of the present invention is to prevent the sheet from sticking to a pressure tool or an object to be pressure-bonded, improve the workability of the pressure-bonding process, and have good durability of the sheet itself and not easily polluting the surroundings. To provide a rubber sheet.

[0006]

The above objects of the present invention are as follows.
At least one surface of the sheet has an arithmetic mean of 0.8 μm
It was achieved by a silicone rubber sheet for thermocompression bonding, which has irregularities of ˜5 μm. The silicone rubber sheet preferably contains carbon black and / or a good thermal conductive filler having a volatile content other than water of 0.5% by weight or less.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The silicone rubber sheet used in the present invention is obtained by blending an organopolysiloxane, a filler and a curing agent, molding the composition into a sheet and then curing it. The above-mentioned organopolysiloxane has an average degree of polymerization of 200.
It is above, and it is preferable that it is represented by the following average composition formula (1). R _n SiO _{(4-n) / 2} (1) R in the above formula represents a substituted or unsubstituted monovalent hydrocarbon group and / or hydroxyl group, and n is a positive number from 1.95 to 2.05. Represents a number. Specific examples of R include alkyl groups such as methyl group, ethyl group and propyl group, cycloalkyl groups such as cyclopentyl group and cyclohexyl group, alkenyl groups such as vinyl group and allyl group, aryl groups such as phenyl group and tolyl group. Alternatively, a halogenated hydrocarbon group in which these hydrogen atoms are partially substituted with chlorine atoms, fluorine atoms and the like can be mentioned. In the present invention, it is preferable that the main chain of the organopolysiloxane is composed of a dimethylsiloxane unit, or that the main chain of this organopolysiloxane has a vinyl group, a phenyl group, a trifluoropropyl group or the like introduced therein.
The end of the molecular chain may be blocked with a triorganosilyl group or a hydroxyl group, and examples of the triorganosilyl group include a trimethylsilyl group, a dimethylvinylsilyl group, a trivinylsilyl group and the like. The degree of polymerization of this organopolysiloxane is preferably 200 or more, and the viscosity at 25 ° C. is preferably 300 cs or more. If the degree of polymerization is 200 or less, the mechanical strength after curing tends to be poor and the composition tends to become brittle.

As the filler, when priority is given to heat resistance, it is preferable to use carbon black whose volatile content other than water is 0.5% by weight or less. It is preferable to select a conductive filler. Carbon black having a volatile content other than water of 0.5% by weight or less improves the heat resistance of the silicone rubber sheet, improves its thermal conductivity and mechanical strength, and imparts antistatic properties due to electrical conductivity. Is. Depending on the manufacturing method, carbon black is manufactured by furnace black,
It is classified into channel black, thermal black, acetylene black, etc., but the volatile matter other than water is 0.5%.
As the following carbon black, acetylene black, conductive carbon black disclosed in JP-A-1-272667 and the like are preferable. The method for measuring volatile components other than water is described in JIS K 6221 "Testing method for carbon black for rubber". The specific content is as follows. It is to measure the subsequent volatilization loss. The blending amount of the carbon black is preferably 20 to 150 parts by weight, and particularly preferably 40 to 100 parts by weight with respect to 100 parts by weight of the organopolysiloxane. Two
If it is less than 0 parts by weight, the thermal conductivity will be insufficient and
If the amount is more than parts by weight, compounding becomes difficult and molding processability becomes extremely poor.

Examples of the filler having good thermal conductivity which can be used in the present invention include inorganic powders such as aluminum oxide, boron nitride, aluminum nitride, aluminum hydroxide, magnesium oxide, zinc oxide and quartz, or silver, nickel, Metal powders such as copper and iron are suitable. The blending amount of these good thermal conductive fillers is such that organopolysiloxane 10
It is preferably 50 to 1,200 parts by weight, and particularly preferably 100 to 1,000 parts by weight, based on 0 parts by weight. If it is less than 50 parts by weight, the thermal conductivity will be insufficient, and if it exceeds 1,200 parts by weight, the moldability will be poor and the mechanical strength after curing will be low and the flexibility of the rubber will be lost. Further, carbon black and a filler having good thermal conductivity may be used in combination.

The curing agent used in the present invention can be appropriately selected from those conventionally known for curing silicone rubber. For example, in the case of radical reaction, di-t-butyl peroxide, 2,5-
Dimethyl-2,5-di (t-butylperoxy) hexane,
Organic peroxides such as dicumyl peroxide are listed,
The blending amount thereof is preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of organopolysiloxane.

When the organopolysiloxane has two or more alkenyl groups, addition consisting of an organohydrogenpolysiloxane containing two or more hydrogen atoms bonded to silicon atoms in one molecule and a platinum group metal-based catalyst. A reaction curing agent may be used. The amount of the organohydrogenpolysiloxane blended is preferably such that the molar ratio of hydrogen atoms bonded to silicon atoms to the alkenyl groups of the organopolysiloxane (≡Si—H / alkenyl group) is 0.5 to 5. The platinum group metal-based catalyst is preferably 1 ppm to 1,000 ppm with respect to the organopolysiloxane.

When the organopolysiloxane contains two or more silanol groups, condensation reaction curing of an organosilicon compound having two or more hydrolyzable groups such as alkoxy groups, acetoxy groups, ketoxime groups and propenoxy groups. Agent. In the present invention, it is preferable to use an organic peroxide or an addition reaction curing agent as the curing agent because of ease of molding.

In the present invention, if necessary, reinforcing silica filler such as hydrophilic silica or hydrophobic silica, clay,
Calcium carbonate, diatomaceous earth, fillers such as titanium dioxide, low molecular siloxane esters, dispersants such as silanol group-containing organosilicon compounds, silane coupling agents,
An adhesion-imparting agent such as a titanium coupling agent, a platinum group metal-based catalyst for imparting flame retardancy, tetrafluoropolyethylene particles for increasing the green strength of the rubber compound, and the like may be added.

As a method for compounding the present silicone rubber compound, the above components may be kneaded by using a mixer such as a two-roll, kneader, Banbury mixer, planetary mixer or the like, but generally, just before use. It is preferable to add a curing agent to the. As a method for molding a silicone rubber sheet, a method of heat-pressing and curing a silicone rubber compound containing a curing agent in a mold, a calender, a method of heat-curing after processing into a predetermined shape with an extruder or the like, Liquid silicone rubber compound or liquid silicone rubber compound dissolved in a solvent such as toluene is coated on a film such as polyethylene terephthalate (PET), dried and then the solvent is removed, followed by heat curing. can give. The thickness of the silicone rubber sheet thus molded is preferably in the range of 0.1 to 10 mm. If the thickness is 0.1 mm or less, it is not possible to sufficiently follow the body to be pressure-bonded, so that the pressure is applied unevenly. Also, 1
When the thickness is 0 mm or more, the heat transfer becomes poor.

In the present invention, at least one surface of the silicone rubber sheet has irregularities to reduce tackiness and impart releasability.
The arithmetic average surface roughness needs to be in the range of 0.8 μm to 5 μm. If the unevenness is 0.8 μm or less, the silicone sheet tends to stick, and if it is 5 μm or more, the electrical connection of the electrodes becomes unstable, which is not preferable. Further, when the unevenness is provided on both surfaces, the roughness of both surfaces may be the same or different. The arithmetic average surface roughness is measured according to JIS B0601. It is preferable to provide the unevenness by embossing because it is inexpensive and quick.

The method for imparting embossing to both surfaces of the silicone rubber sheet is as follows: 1) When a sheet is produced using a calender roll, the silicone rubber sheet composition is dispensed on the rough surface of the roughened plastic film. Then
Before curing, the dispensing sheet surface opposite to the plastic surface is pressed against a roll with embossing to transfer the embossing, then after curing, the silicone rubber is peeled off from the plastic film, 2) vulcanized silicone A method of roughening a rubber sheet by sand blasting, etc. 3) Coating on one side of a plastic film that has been embossed on both sides, tightly winding it before curing, placing it in the oven as it is, and vulcanizing it, then silicone from the plastic film There is a method to peel off the rubber.

Since the silicone rubber sheet for thermocompression bonding of the present invention is excellent in heat resistance, thermal conductivity, strength and workability and has elasticity as a silicone rubber, it can be laminated with a press molding machine to form a laminated board or a flexible printed circuit board. A sheet used for the purpose of uniformly applying pressure while transferring heat, and an anisotropic conductive adhesive for the electrodes connected to the liquid crystal display and the lead electrodes of the FPC on which the driving LSI is mounted. It is particularly effective as a sheet used for electrical and mechanical connection by interposing and thermocompression bonding.

[0018]

EFFECTS OF THE INVENTION The silicone rubber sheet for thermocompression bonding of the present invention, in which at least one surface of the sheet is provided with irregularities,
Since at least one of the surfaces has irregularities, it has the advantage that it has good releasability from the pressure tool or the object to be pressure-bonded and does not contaminate the surroundings. Therefore, not only the durability of the sheet itself is improved, but also the workability of the thermocompression bonding process is improved. Also,
At the time of pressurization, the sheet moves slightly without adhering, so that air can not be trapped in the pressure-bonded portion and uniform pressure can be applied.

[0019]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. Example 1. 100 parts by weight of methylvinylpolysiloxane having an average degree of polymerization of 8,000, which is composed of 99.85 mol% of dimethylsiloxane units and 0.15 mol% of methylvinylsiloxane units, has a mean particle size of 40 nm and a volatile component other than water. 50 parts by weight of 0.10% acetylene black and 5 parts by weight of reinforcing silica (Aerosil R-972: trade name, manufactured by Degussa) were blended with a two-roll mill and kneaded to homogenize. To 100 parts by weight of this silicone rubber compound, 0.1 part by weight of an isopropyl alcohol solution of chloroplatinic acid (platinum content: 2% by weight), and an acetylenic alcohol (3-methyl-1) which is a reaction inhibitor.
-Butyn-3-ol) 0.05 parts by weight and the following formula (2)
Methyl hydrogen polysiloxane represented by 1.2
A part by weight was added, and the mixture was well kneaded with a two-roll to prepare a curable silicone rubber compound.

The silicone rubber compound obtained was
The film was dispensed to a thickness of 0.30 mm using a calender molding machine, and then transferred onto a 100-μm-thick polyethylene terephthalate (PET) film embossed on one side with an arithmetic mean surface roughness of 0.7 μm. Then, an embossing roll having an arithmetic average surface roughness of 3.5 μm is pressed against the surface of the dispensing sheet opposite to the PET film to transfer the embossing to the surface of the silicone rubber, and then in a heating furnace at 160 ° C. for 5 minutes. Cured through. Next, the silicone rubber sheet was peeled off from the PET film, and post-cured at 200 ° C. for 2 hours to prepare a silicone rubber sheet for thermocompression bonding. The surface roughness of the surface on which the emboss is transferred is measured by a surface roughness meter Surftest 501 (trade name of Mitutoyo Corporation).
When measured using, the arithmetic average surface roughness is 2.9μ.
It was m.

Example 2. Dimethylsiloxane unit 99.
100 parts by weight of methylvinylpolysiloxane having an average degree of polymerization of 8,000 and comprising 85 mol% and 0.15 mol% of methylvinylsiloxane unit, and aluminum oxide powder (alumina AL-45: Showa Denko as a good thermal conductive filler). (Trade name of Co., Ltd.) 400 parts by weight, specific surface area 200 m
30 parts by weight of silica fine powder (Aerosil 200: trade name of Nippon Aerosil Co., Ltd.) of ² / g and 5 parts by weight of α, ω-dihydroxymethylpolysiloxane represented by the following formula (3) were added to a kneader. Knead evenly using
It heat-processed at 50 degreeC for 2 hours.

After cooling, 100 parts by weight of this silicone rubber compound was added with an organic peroxide (C-2) as a curing agent.
3: 1.5 parts by weight of trade name manufactured by Shin-Etsu Chemical Co., Ltd.) was added with a two-roll mill and mixed, and then a calendering machine was used to dispense to a thickness of 0.30 mm. Next, embossed on one side with arithmetic mean surface roughness of 0.7 μm and thickness of 100 μm
The above-mentioned dispensed silicone rubber composition was transferred onto a PET film, and then an embossing roll having an arithmetic average surface roughness of 3.5 μm was pressed against the surface of the dispensing sheet opposite to the PET film to emboss the silicone rubber surface. After being transferred, it was cured by passing through a heating furnace at 160 ° C. for 5 minutes. Next, the silicone rubber sheet was peeled off from the PET film and post-heat cured at 200 ° C. for 4 hours to prepare a silicone rubber sheet for thermocompression bonding.

Example 3. Dimethylsiloxane unit 99.
100 parts by weight of methylvinylpolysiloxane having an average degree of polymerization of 8,000 consisting of 85 mol% and 0.15 mol% of methylvinylsiloxane unit, and acetylene black 50 having an average particle size of 40 nm and a volatile content other than water of 0.10%. Parts by weight and reinforcing silica (Aerosil R-972:
5 parts by weight of Degussa (trade name) was blended with a two-roll mill and kneaded to homogenize. To 100 parts by weight of this silicone rubber compound, 0.1 part by weight of an isopropyl alcohol solution of chloroplatinic acid (platinum amount: 2% by weight) and an acetylenic alcohol (3-methyl-1) which is a reaction inhibitor.
-Butyn-3-ol) 0.05 parts by weight and 1.2 parts by weight of methylhydrogenpolysiloxane represented by the above formula (2) are added, and the mixture is well kneaded with a two-roll mill to produce a curable silicone rubber. The compound was prepared.

This silicone rubber compound was dispensed to a thickness of 0.30 mm using a calender molding machine, and transferred onto a PET film having a thickness of 100 μm and an arithmetic mean roughness of 0, and heated in a heating furnace at 160 ° C. It was passed through for 5 minutes to cure. Next, the silicone rubber sheet was peeled off from the PET film, post-heat cured at 200 ° C. for 2 hours, and then one side of this sheet was sandblasted to give a silicone for pressure bonding having an embossed surface with an arithmetic mean surface roughness of 1.8 μm. A rubber sheet was produced.

Example 4. Dimethylsiloxane unit 99.
100 parts by weight of methylvinylpolysiloxane having an average degree of polymerization of 8,000 and comprising 85 mol% and 0.15 mol% of methylvinylsiloxane unit, and aluminum oxide powder (alumina AL-45: Showa Denko as a good thermal conductive filler). (Product name of Co., Ltd.) 400 parts by weight, specific surface area of 200 m
30 parts by weight of silica fine powder (Aerosil 200: trade name of Nippon Aerosil Co., Ltd.) of ² / g and 5 parts by weight of α, ω-dihydroxymethylpolysiloxane represented by the above formula (3) are kneader. Knead evenly using
Heat treatment was performed at 0 ° C. for 2 hours.

After cooling, 100 parts by weight of this silicone rubber compound was added with an organic peroxide (C-2) as a curing agent.
4: 1.5 parts by weight of Shin-Etsu Chemical Co., Ltd.) was added with a two-roll mill, mixed, and then dissolved in xylene to obtain 60
% Xylene solution, and using a comma coater on the embossed surface of a PET film having a thickness of 100 μm and embossed on one side with an arithmetic mean surface roughness of 0.7 μm.
After coating to a thickness of mm, xylene was evaporated to dryness at 80 ° C. Then the arithmetic mean surface roughness is 3.5 μm
The embossing roll was pressed against the surface of the coating sheet on the side opposite to the PET film to transfer the embossing to the surface of the silicone rubber, and then passed through a heating furnace at 160 ° C. for 5 minutes to be cured. Next, this silicone rubber sheet was peeled off from the PET film and post-heat cured at 200 ° C. for 4 hours to prepare a silicone rubber sheet for thermocompression bonding.

Comparative Example 1. Using the silicone rubber compound of Example 1, a calender molding machine was used to obtain a thickness of 0.
After being divided into 30 mm, it was transferred onto a PET film having a thickness of 100 μm and an arithmetic average surface roughness of 0, and passed through a heating furnace at 160 ° C. for 5 minutes to be cured. Next, the silicone rubber sheet was peeled off from the PET film, and talc powder having an average particle diameter of 13 μm was rubbed on the surface of the sheet with gauze and applied evenly. In addition, 200 in the dryer
After heat treatment at 4 ° C. for 4 hours, this sheet was washed while rubbing with a sponge in running water to remove excess powder and then dried to prepare a thermocompression-bonded silicone rubber sheet.

Comparative Example 2. Using the silicone rubber compound of Example 2, a calender molding machine was used to obtain a thickness of 0.
After being divided into 30 mm, it was transferred onto a PET film having a thickness of 100 μm and an arithmetic average surface roughness of 0, and passed through a heating furnace at 160 ° C. for 5 minutes to be cured. Next, the silicone rubber sheet was peeled off from the PET film, and mica powder having an average particle size of 20 μm was rubbed on the sheet with gauze,
It was applied evenly. Furthermore, after heat-treating at 200 ° C. for 4 hours in a dryer, this sheet is washed by rubbing with a sponge in running water to remove excess powder, and then water is dried,
A silicone rubber sheet for thermocompression bonding was produced.

Comparative Example 3. A silicone rubber sheet for thermocompression bonding was produced in exactly the same manner as in Example 3 except that embossing was not performed.

Comparative Example 4. After applying primer C (trade name of Shin-Etsu Chemical Co., Ltd.) to a 12 μm-thick aromatic polyimide film (Kapton: trade name of Toray Dupont Co., Ltd.), which is a heat-resistant resin film, at room temperature It was dried for 30 minutes. On the other hand, the curable silicone rubber compound produced in Example 1 was processed to a thickness of 0.
After being divided into 30 mm, they were transferred onto a PET film having a thickness of 100 μm and an arithmetic average surface roughness of 0. Next, the above-mentioned Kapton film coated with the primer was pressure-bonded onto the sheet, and passed through a heating furnace at 160 ° C. for 5 minutes to cure the silicone rubber compound. Then PET
The film was peeled off and heat-treated at 200 ° C. for 4 hours in a dryer to prepare a silicone rubber composite sheet for thermocompression bonding.

(Crimping Test) Examples 1 to 4 and Comparative Examples 1 to 4
A Teflon film (Teflon is a registered trademark) manufactured by DuPont Japan Limited with a thickness of 30 μm is formed under the back surface of the thermocompression-bonded silicone rubber sheet prepared in
22μ thickness with two FPCs equipped with copper electrodes of μm pitch
After placing the anisotropic conductive adhesive of m (aligning the upper and lower copper electrodes), set it on the crimping machine and set it to 340
The surface of the thermocompression-bonded silicone rubber sheet was pressure-bonded for 20 seconds with a pressing force of 40 kgf / cm ² using a pressure tool heated to ℃. This pressure bonding was repeated, and the number of times until the anisotropic conductive adhesive could not be heat-cured was measured under the state of close contact of the sheet with the pressure tool and uniform pressure. This number was confirmed by the conduction of the copper electrodes of the upper and lower FPCs. However, in the case of the silicone rubber composite sheet for thermocompression bonding of Comparative Example 4, the measurement was performed with the Kapton film side facing the pressure tool. Further, since the thickness of the film is added and the heat transfer is deteriorated, the pressing time is extended to 25 seconds. The results are shown in Table 1.
As shown in.

[0032]

[Table 1]

In the case of Comparative Examples 1 and 2, the pressure tool gradually becomes soiled when continuously used, and therefore cleaning is required. On the other hand, in the case of Examples 1 to 4, there is no need to clean the pressure tool and durability is achieved. In the case of Comparative Example 3, it was confirmed that washing was required twice / day, and the crimping machine was cooled each time, so that it was very troublesome. Next, regarding Example 1 and Comparative Example 4, the pressing force of the pressure tool was set to 30.
When a pressure-bonding test was performed under the same conditions except that the pressure was reduced to kgf / cm ² , in the case of Example 1, the conduction between the copper electrodes of the upper and lower FPCs was good, but that of Comparative Example 4. In some cases, some conduction failure occurred. The silicone rubber composite sheet for thermocompression bonding of Comparative Example 4 has no problem with the adhesion to the pressure tool and the stain of the pressure tool, but it is necessary to extend the pressure bonding time and increase the pressing pressure as compared with the present invention. Was confirmed.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideo Kanai             Gunma Prefecture Annaka City Isobe 2-13-1 Shi Co., Ltd.             Inside the mold (72) Inventor Toru Tsuchiya             Gunma Prefecture Annaka City Isobe 2-13-1 Shi Co., Ltd.             Inside the mold (72) Inventor Masahiro Mogi             Gunma Prefecture Annaka City Isobe 2-13-1 Shi Co., Ltd.             Inside the mold (72) Inventor Toru Takamura             2-6-1 Otemachi, Chiyoda-ku, Tokyo Shin-Etsu             Gaku Kogyo Co., Ltd. F-term (reference) 4F071 AA67 AB03 AB26 AE17 AF55                       AF58 AG05 AG22 AG28 AH19                       BB04 BC01 BC08 BC12 BC16                 4J002 CP031 DA036 DA077 DA087                       DE077 DE107 DE237 DF017                       DJ017 DK007 FD016 FD017                       GF00

Claims (5)

[Claims] 1. A silicone rubber sheet for thermocompression bonding, wherein at least one surface of the sheet has irregularities having an arithmetic average roughness of 0.8 μm to 5 μm. 2. The silicone rubber sheet for thermocompression bonding according to claim 1, wherein the silicone rubber sheet contains carbon black having a volatile content other than water of 0.5% by weight or less. 3. The silicone rubber sheet for thermocompression bonding according to claim 1, wherein the silicone rubber sheet contains a good thermal conductive filler. 4. The thickness of the silicone rubber sheet is 0.
It is 1-10 mm, The silicone rubber sheet for thermocompression bonding in any one of Claims 1-3. 5. The silicone rubber sheet for thermocompression bonding according to claim 1, wherein the irregularities on the surface are provided by embossing.