JP5061308B2 - Adhesive sheet - Google Patents

Description

The present invention relates to a contact sheet for fixing an article. In particular, in a semiconductor device manufacturing process, the present invention relates to a contact sheet used for protecting a circuit pattern on a wafer surface when grinding the back surface of the wafer, fixing a wafer when dicing (cutting) the wafer, and the like. In order to cut a hard and brittle material such as a printer head, glass / epoxy substrate, glass, ceramics or the like into small chips, these are fixed on the hard material and cut. At this time, it is related with the contact | adherence sheet | seat used in order to fix a to-be-cut object on a hard material.

In a manufacturing process of a semiconductor device such as an IC or LSI, a wafer after formation of a circuit pattern is usually subjected to processing such as grinding and etching in order to reduce its thickness. Further, the processed wafer is diced into chips. In these steps, an adhesive sheet is usually used for various purposes. That is, during grinding or the like, an adhesive sheet is attached to the circuit pattern surface for the purpose of protecting the circuit pattern on the wafer surface. Further, during dicing, the wafer is fixed to the adhesive sheet and held for the purpose of fixing the wafer when cutting the wafer and preventing the chips formed from scattering.

  The pressure-sensitive adhesive layer in this pressure-sensitive adhesive sheet has a strong adhesive force to sufficiently fix the wafer during use and a weak adhesive force to easily peel the wafer (chip) from the sheet after use. is required. For this reason, in recent years, a radiation-curable pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer that undergoes a polymerization reaction upon irradiation and is cured on a substrate is used as the pressure-sensitive adhesive sheet.

  The radiation curable pressure-sensitive adhesive sheet is usually used as follows. That is, first, the sheet is attached to an article to be processed such as a wafer, and in this state, the article is subjected to processing such as grinding and dicing. Next, by irradiating the pressure-sensitive adhesive sheet with radiation, the pressure-sensitive adhesive layer on the substrate is cured to lose the adhesiveness, and the processed article is peeled off from the pressure-sensitive adhesive sheet.

  As described above, in the radiation curable pressure-sensitive adhesive sheet, the pressure-sensitive adhesive layer is designed so that the adhesiveness of the surface is almost lost after being irradiated and cured, whereas the pressure-sensitive adhesive layer adheres to the adherend before irradiation. Designed to be extremely high. Therefore, in the said adhesive sheet, the adhesive strength of desired strength is each achieved before and after the use.

  However, the radiation-curable pressure-sensitive adhesive tape is sticky due to high adhesiveness on the surface of the pressure-sensitive adhesive layer before irradiation with radiation. For this reason, when the adhesive sheet is mistakenly attached to an object other than the target adherend, if an attempt is made to peel it off without irradiating with radiation, adhesive residue of the adhesive substance occurs on the object. In particular, when the pressure-sensitive adhesive sheet is adhered to a semiconductor wafer, ceramics, or the like, which is an adherend, the surface area of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet is considerably larger than the area of the adherend portion of the adherend. The pressure-sensitive adhesive sheet adheres to a part of a jig used for sticking, for example, a sheet holder, an adherend mounting table, a rubber roller for sticking the sheet, or an automated device thereof, and an adhesive residue is generated in this part. Sometimes. Usually, the design of the sheet sticking jig and apparatus is considered so that the adherend is not contaminated by such adhesive residue. However, for example, when the pressure-sensitive adhesive tape adheres again to the adhesive remaining portion, the pressure-sensitive adhesive sheet is firmly attached, and therefore, a continuous operation of attaching the pressure-sensitive adhesive sheet becomes increasingly difficult.

  In addition, if an attempt is made to peel off a portion where unnecessary sticking as described above has occurred, a part of the adhesive sheet may be peeled off from the target adherend, or the adhesive sheet may be distorted such as stretching. Therefore, the purpose of the pressure-sensitive adhesive sheet cannot be sufficiently achieved. In addition, the radiation-curable pressure-sensitive adhesive sheet generates a strong odor when cured by irradiating light, causing the operator to feel uncomfortable, and was never preferred in terms of health and hygiene. .

  In recent years, IC cards have been widely used, and further reduction in thickness has been desired. For this reason, it is necessary to reduce the thickness of a semiconductor chip, which has conventionally been about 350 μm, to a thickness of 50 to 100 μm or less. Conventionally, a soft substrate has been used as the base material of the pressure-sensitive adhesive sheet used in the process of manufacturing a semiconductor chip. However, in the pressure sensitive adhesive sheet using a soft base material, the tension applied at the time of sticking accumulates as residual stress. When the wafer has a large diameter or is ground extremely thin, the residual stress of the pressure-sensitive adhesive sheet is superior to the strength of the wafer, and the wafer is warped by a force for eliminating the residual stress. In addition, since the wafer is fragile after grinding, the soft substrate may break the wafer during transportation. For this reason, a method of fixing a wafer to a hard material such as a glass plate or an acrylic plate via a double-sided pressure-sensitive adhesive sheet and grinding it has been studied.

  Further, in order to cut a hard and brittle material such as a printer head, glass / epoxy substrate, glass, ceramics or the like into small chips, these are fixed on the hard material and cut. At this time, a double-sided pressure-sensitive adhesive sheet is used to fix the object to be cut on the hard material. However, it is extremely difficult to peel off an object obtained by bonding hard materials with a conventional double-sided pressure-sensitive adhesive sheet. When brittle materials such as wafers are used, it is impossible to avoid destruction.

  For this reason, the advent of a double-sided pressure-sensitive adhesive sheet or a close-contact sheet suitable for fixing a semiconductor wafer or the above-described various cut objects on a hard material is desired. Further, when processing a semiconductor wafer, a surface protection sheet is required for back grinding and an adhesive sheet for fixing the wafer is required for dicing, which is complicated in process management. Moreover, since the wafer is fragile, it may be damaged during the transfer between such processes.

  Accordingly, there is a demand for the emergence of a process that can perform a series of processes such as back surface grinding, dicing, and conveyance of the wafer in the same form, can easily manage the process, and can prevent breakage.

Patent Document 1 provides a double-sided adhesive sheet in which silicone layers are provided on both sides of a base material in order to solve these problems. However, if the surface of the adherend was smooth, it was possible to fix and adhere well, but if the surface was rough, the adhesion was lost and it could not be fixed. For example, a large number of semiconductors and the like are provided on one surface of the wafer, and the surface becomes uneven, and the surface average roughness Ra is higher than the smoothness of the glass surface and the like. As the wafer has a high average surface roughness, the double-sided adhesive sheet of Patent Document 1 is difficult to fix.

JP 2004-26950 A

The present invention solves the above-described problems, prevents unnecessary adhesion to other than the adherend in the semiconductor manufacturing process, improves adherence of the adherend and workability after sticking, and light irradiation. It is an object of the present invention to provide an adhesive sheet that does not have a problem of odor generated when the adhesive layer is cured by the above. Furthermore, the present invention provides a contact sheet that can fix an object to be cut such as a thin film wafer or ceramics on a hard material and can be processed accurately and efficiently. The contact sheet can be suitably used for a process capable of performing back surface grinding and dicing of a wafer in the same form. The adhesive sheet of the present invention has a roughened surface of the adherend, and is an adhesive sheet that can be fixed even by a conventional adhesive sheet that cannot be fixed. It fixes not only wafers but also articles other than wafers. It is a contact sheet that can be used.

The present invention provides a contact sheet provided with at least one surface adhesion layer of the base material, the adhesive layer is Ri der 80 following an Asker CSC2 hardness ASKER FP hardness 25 or more, a thickness of 10 to 100 [mu] m, and the following is a contact sheet you meet the requirements.
A: The adhesion layer is composed of a silicone composed of a linear polyorganosiloxane having vinyl groups only at both ends, a silicone composed of a linear polyorganosiloxane having vinyl groups at both ends and side chains, and only at the ends. It is obtained by crosslinking at least one silicone selected from a silicone comprising a branched polyorganosiloxane having a vinyl group and a silicone comprising a branched polyorganosiloxane having a vinyl group at the terminal and side chain.
B: The number average molecular weight of the silicone is 25,000 to 100,000.

When the adhesive sheet of the present invention is used in the production process of a semiconductor, unnecessary adhesion to other than the adherend is prevented, the adherence of the adherend and the workability after adhesion are improved, and the adhesive layer is cured by light irradiation. It is an object of the present invention to provide an adhesive sheet that does not have a problem of odor that sometimes occurs. Furthermore, the present invention provides a contact sheet that can fix an object to be cut such as a thin film wafer or ceramics on a hard material and can be processed accurately and efficiently. Moreover, the contact sheet of the present invention can be suitably used for a process capable of performing back surface grinding and dicing of a wafer in the same form.

  Moreover, since the surface of the adherend is rough, the conventional adhesive sheet cannot be fixed, but according to the adhesive sheet of the present invention, it can be fixed.

The adhesion sheet as used in the present invention is a force for shifting the adhesion sheet parallel to the bonded surface of the adhesion layer surface of the adhesion sheet and the adherend having a flat surface (hereinafter referred to as shearing force). In spite of the high value, the force when peeling the adhesive sheet from the adherend (hereinafter referred to as peeling force) is less than 10 mN / 12.7 mm and almost zero. Accordingly, a weak pressure-sensitive adhesive sheet, such as a generally called weak pressure-sensitive adhesive sheet, has a high shearing force and a slight peeling force (specifically, a peeling force of 100 mN / 12.7 mm or more). It has different physical properties.

  The adhesion sheet of the present invention is obtained by laminating an adhesion layer composed of an adhesion agent on at least one surface of a substrate. The main components of the adhesive are silicone, polyurethane, polynorbornene rubber, chloroprene rubber, ethylene-propylene-diene rubber, chlorosulfonated polyethylene rubber, styrene-butadiene-styrene, styrene-isoprene-styrene, styrene-ethylene-butylene- Styrene, styrene-ethylene / propylene-styrene and the like can be used.

  Further, the adhesion layer has an Asker FP hardness of 25 to 100 or an Asker CSC2 hardness of 0 to 80. If it is less than the above range, it will be too soft and part of the adhesion layer will remain if it is peeled off from the adherend. If it exceeds the above range, it is too hard to be fixed to the adherend. The more preferable adhesion layer has an Asker FP hardness of 40 to 100 or an Asker CSC2 hardness of 0 to 20.

  In order to adjust the hardness of the adhesion layer, a plasticizer can be added depending on the main component material. Examples of the plasticizer include paraffinic, naphthenic, and aromatic mineral oils, synthetic oils such as alkylbenzene and alkylnaphthalene, and ester plasticizers such as dioctyl phthalate and dioctyl adipate. The addition amount of the plasticizer is 10 to 300 parts by weight, more preferably 20 to 150 parts by weight, per 100 parts by weight of the main component of the adhesion layer. If the amount of the plasticizer is less than this range, the hardness cannot be reduced, and if it exceeds this range, the plasticizer may ooze out from the adhesion layer.

  In order to improve the strength of the adhesion layer and prevent permanent distortion, a filler may be added to the adhesion layer. Examples of the filler include carbon black, calcium carbonate, silica, magnesium hydroxide, and hydrated alumina.

  Generally, when the hardness meter indicates between 10 and 90 points, the most significant difference is assumed. For example, when the Asker hardness FP (using Asker FP type hardness meter) shows 90 to 100 points, FP It is preferable to measure with an Asker CSC type 2 hardness meter that measures a material harder than the mold. Conversely, when 0-10 points are indicated by Asker CSC2 hardness (using Asker CSC2 hardness meter), it is preferable to measure with an Asker FP type hardness meter.

  The hardness of the adhesion layer of the adhesion sheet of the present invention is a super-soft composition that cannot be measured with a general rubber hardness meter Asker C type (conforming to JIS K 7312). Although the adhesion layer of the double-sided adhesion sheet of the Example of patent document 1 can be measured with an Asker C type hardness meter, it is a hard thing which cannot be measured with the Asker FP type and CSC2 type hardness meter defined in the present invention.

  Therefore, if the surface of the adherend is smooth, the article can be fixed with the double-sided adhesive sheet of Patent Document 1, but cannot be fixed as the surface becomes rough. The adhesive sheet of the present invention can be fixed even if the double-sided adhesive sheet of Patent Document 1 cannot be fixed because the surface of the adherend is rough.

  The main component of the adhesion layer is preferably silicone when heat resistance, solvent resistance, weather resistance, and the like are required. As the silicone, for example, an addition polymerization type silicone polymer can be used. Examples of the addition polymerization type silicone resin include those polymerized by a platinum catalyst. As the properties of the adhesion layer that meets the object of the present invention, it is required that the surface of the adhesion layer is uneven along the unevenness of the surface of the adherend, having flexibility such as gel. Further, when peeling, it is required to be easily peeled with a small peeling force.

As silicone having such properties, a silicone composed of a linear polyorganosiloxane having vinyl groups only at both ends, a silicone composed of a linear polyorganosiloxane having vinyl groups at both ends and side chains, and a terminal. a silicone comprising a branched polyorganosiloxane having vinyl groups only, the end and side chains to crosslink the at least one silicone selected from silicone consisting of branched polyorganosiloxane having a vinyl group is used one made by the good.

  As one form of these silicones, a linear polyorganosiloxane having vinyl groups only at both ends is a compound represented by the following general formula (Formula 1).

(Wherein R represents the following organic group, and n represents an integer)

(Wherein R represents the following organic group, m and n represent an integer)
The organic group (R) bonded to the silicon atom other than the vinyl group may be different or of the same type. Specific examples include alkyl groups such as methyl, ethyl and propyl groups, and aryl groups such as phenyl and tolyl groups. Or a monovalent hydrocarbon group other than the same or different unsubstituted or substituted aliphatic unsaturated group in which part or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with a halogen atom, a cyano group, or the like. Preferable examples include those having at least 50 mol% of a methyl group. These diorganopolysiloxanes may be used alone or as a mixture of two or more thereof.

A silicone comprising a linear polyorganosiloxane having vinyl groups at both ends and side chains is a compound in which a part of R in the above general formula (Formula 1) is a vinyl group. Silicone consisting branched polyorganosiloxane having vinyl groups only at the terminal is a compound which is expressed by the above general formula (Formula 2). Some of the R of the branched poly consisting polyorganosiloxane silicone the above-mentioned general formula (Formula 2) having a vinyl group at the terminal and side chain is a compound which is a vinyl group.

  Here, a known crosslinking agent may be used for the crosslinking reaction. Examples of the crosslinking agent include organohydrogenpolysiloxane. Organohydrogenpolysiloxane has at least three hydrogen atoms bonded to silicon atoms in one molecule, but from a practical viewpoint, one having two ≡SiH bonds in the molecule is 50% by weight of the total amount. It is preferable that the remainder contains at least three ≡SiH bonds in the molecule.

  The platinum-based catalyst used for the crosslinking reaction may be a known one, including chloroplatinic acid such as chloroplatinic acid and chloroplatinic acid, alcohol compounds of chloroplatinic acid, aldehyde compounds or chloroplatinic acid and various olefins. And chain salts. The cross-linked silicone has flexibility such as a silicone gel, and this flexibility makes it easy to adhere to the adherend.

  Although the shape of the commercial item of silicone includes a solventless type, a solvent type, and an emulsion type, any type can be used. Above all, the solventless type is very advantageous in terms of safety, hygiene, and air pollution because it does not use a solvent. In addition, the coating thickness of the adhesion layer needs to exceed 1.1 μm, and in some cases, it is provided with a thickness of several millimeters. Therefore, in the case of solvent type silicone or emulsion type silicone, the solvent is dried at the time of coating. Therefore, it is preferable to use a solventless silicone as the silicone used in the present invention.

  The addition of a plasticizer for adjusting the hardness of the adhesion layer is required to be non-added because a slight amount of plasticizer permeates depending on the article to be fixed. In the case where the adhesion layer is formed of silicone, the adhesion layer can be formed of silicone alone without adding a plasticizer when a silicone having a number average molecular weight of 25,000 to 100,000 is used. If it is less than the above range, it becomes too soft and permanent deformation occurs. If it exceeds the above range, it will become too hard and will be outside the hardness range of the first invention. A more preferable number average molecular weight of silicone is 35,000 to 80,000.

The adhesion layer may be formed on both surfaces of the substrate, or may be only one surface. When an adhesive sheet having an adhesive layer formed on only one side is used for fixing a silicone wafer, the base surface without the adhesive layer and the pedestal can be fixed by vacuuming the surface to be contacted. .
A separator such as a resin film or paper can be bonded to the surface of the adhesive layer in order to prevent the surface of the adhesive layer from being contaminated or to prevent foreign matter from adhering or to improve the handling of the adhesive sheet.

In general, the thickness of the adhesion layer is preferably in the range of 1.1 to 3000 μm. Preferably, it is good in it being 10-50 micrometers. When the thickness of the adhesion layer is less than 1.1 μm, it becomes difficult to adhere to the adherend, the shearing force in the adhesion surface direction of the adhesion sheet to the adherend becomes less than 1.0 N / cm ² , There is a possibility that the adhesive sheet will peel off. When the thickness of the adhesion layer exceeds 3000 μm, the amount of the material used for the adhesion layer increases, which is uneconomical.

  In order to improve the adhesion to the adhesion layer on the surface of the substrate, corona discharge treatment, plasma treatment, blast treatment, chemical etching treatment, primer layer coating, etc. may be performed. As a coating method of the adhesion layer coating liquid, a multi-stage roll coater represented by a three-offset gravure coater or a five-roll coater, a direct gravure coater, a bar coater, an air knife coater, or the like is appropriately used.

  Even for adherends of the same material, the thickness of the adhesion layer needs to be changed depending on the surface roughness of the adherend. That is, when the surface roughness of the adherend is in a mirror state such as glass or an acrylic resin plate (surface average roughness Ra measured based on JIS-0601-1994 is 0.01 μm or less), the adhesion layer Even if the thickness of the substrate is small, it adheres well to the adherend and exhibits the above function as an adhesion layer, but the surface roughness of the adherend is not in a mirror state, for example, the surface average roughness measured based on the JIS When the thickness Ra is about 0.1 to 0.2 μm, the lower limit value of the thickness of the adhesion layer needs to be higher than the lower limit value of the thickness of the adhesion layer required for the adherend in the mirror surface state.

  It is good also as a double-sided adhesive sheet by providing an adhesive layer on both sides of the substrate. The material of the adhesion layer may be the same or different. The thickness of each adhesion layer may be set according to the surface roughness of each adherend facing the two adhesion layers as described above, and may be the same thickness or different thicknesses. It may be.

  As the substrate according to the present invention, a single-layer or multilayer film made of polyethylene terephthalate, polyethylene, polystyrene, polypropylene, nylon, urethane, polyvinylidene chloride, polyvinyl chloride, or the like can be used. The thickness of the substrate is usually 5 to 300 μm, preferably 10 to 200 μm.

In order to improve the adhesion to the adhesion layer on the surface of the substrate, corona discharge treatment, plasma treatment, blast treatment, chemical etching treatment, primer layer coating, etc. may be performed.
As a silicone coating method according to the present invention, a multi-stage roll coater represented by a three-offset gravure coater or a five-roll coater, a direct gravure coater, a bar coater, an air knife coater, or the like is used as appropriate.

When the adhesion sheet of the present invention is brought into close contact with the semiconductor mounting surface and the adhesion layer surface of the wafer in the semiconductor wafer manufacturing process, and the substrate and the pedestal of the adhesion sheet are evacuated and adhered, the wafer surface and the adhesion layer surface are strongly adhered. Power works. Since the shearing force for shifting the contact sheet and the adherend parallel to the contact surface is 1.0 N / cm ² or more, the wafer does not come off during grinding of the back surface of the wafer. Similarly, in the wafer dicing process, if processing is performed through the contact sheet, a shape defect due to chipping or displacement due to peeling of the wafer from the contact sheet does not occur.

  After the processing, the cut and formed chips are picked up by a needle from the substrate side of the adhesion sheet and picked up and fixed on the die pad. The adhesion sheet according to the present invention has a peeling force between the wafer and the adhesion sheet (JIS K). 6854) is a minimum value of 10 mN / 12.7 mm or less, so that the chip can be picked up without being damaged.

  In addition, the adhesive sheet of the present invention does not generate a strong odor when irradiated with radiation unlike conventional radiation-curable pressure-sensitive adhesive sheets, and is preferable for hygiene management.

  When processing a wafer thinly to a thickness of 50 to 100 μm or less, the pressure-sensitive adhesive layer in the conventional pressure-sensitive adhesive sheet is soft, so the wafer does not deviate from the surface of the pressure-sensitive adhesive layer. However, the adhesion layer of the adhesive sheet of the present invention is a cross-linked silicone and is a harder layer than the adhesive layer. The above problem will not occur.

  The contact sheet used in the wafer grinding process and the contact sheet used in the dicing process may be used continuously in a continuous process, or may be prepared and used separately. . This is arbitrarily selected depending on the content of the manufacturing process.

  In order to cut hard and brittle materials such as printer heads, glass / epoxy substrates, glass, ceramics, etc. into small chips, these are on a hard material such as a glass plate or acrylic plate with a thickness of about 0.1 to 1.0 mm. The cutting is performed with fixing to. At this time, in order to fix the object to be cut on the hard material, by using the double-sided adhesive sheet of the present invention, cutting can be performed accurately, and the cut object after cutting can be performed by a simple operation. It can be easily peeled off.

The measuring method of the physical property values described above is as follows.
(1) Number average molecular weight It calculated | required by the polystyrene conversion method using the GPC measuring machine (model number: Waters410) by Waters.

(2) Surface roughness Surface average roughness (Ra) surface maximum roughness (Ry) is measured using a surface roughness measuring instrument (Surfcoder SE3500, manufactured by Kosaka Laboratory Ltd.) based on JIS-B0601-1994. did. The radius of the stylus of the measuring instrument is 2.0 μm, the load is 0.3 mN, the cut-off value is 2.5 mm, the measurement length is 12.5 mm, and the feed rate is 0.5 m / min.

(3) Measuring method of shearing force A contact sheet sample is cut into a size of 25 mm × 50 mm square. An adhesion sheet sample is placed on the surface of a bearon texture plate (a sample sample plate for the texture processing of a resin molded product manufactured by Moldtech Co., Ltd., which uses a plurality of sample plates having different surface average roughness for each count). A 2 Kg roll specified in JIS K 0237 is pasted once at a speed of 3 m / min. One end of the adhesive sheet is lifted by about 1 mm, and a 25 mm × 100 mm size cardboard is touched to the adhesive sheet, and is adhered as shown in FIG. 1 using an adhesive tape. Attach a bar tension gauge to the other end of the cardboard. The maximum tension value is read by pulling the bar tension gauge in the direction shown in FIG. 1 at a speed of 25 mm / min.

After applying the adhesive layer coating solution shown in Table 1 to a thickness of 24 μm on one side of a 50 μm PET film, it was crosslinked in an oven at 150 ° C. for 100 seconds to produce the adhesive sheets of Examples 1 and 2 and Comparative Example 1. .
Example 3 An adhesion sheet was prepared in the same manner as in Example 1 except that the adhesion layer coating solution of Example 1 was applied to a thickness of 100 μm.
Example 4: An adhesion sheet was prepared in the same manner as in Example 2 except that the adhesion layer coating solution of Example 2 was applied to a thickness of 100 µm.
Comparative Example 2: An adhesive sheet was prepared in the same manner as Comparative Example 1 except that the adhesive layer coating solution of Comparative Example 1 was applied to a thickness of 100 μm.

Table 1 Adhesion layer coating solution (parts by weight)

Evaluation Method Adhesion of each adhesion sheet to the adherend is measured based on the shearing force measurement method described above by bringing the adhesive sheet into close contact with a plurality of counts.
Evaluation standard (circle): Shear force is 300 g or more.
X: The shearing force is less than 300 g.

  The evaluation results were as shown in Table 2. If the adherend is small in Ra, the contact sheet of Comparative Example 1 is in a practical range with a shearing force of 300 g or more. However, in the case of a bearon texture plate with Ra of 1.16 μm, the shearing force of the contact sheet of Comparative Example 1 is as small as less than 300 g. The adhesive sheets of Examples 1 and 2 are high with a shearing force of 300 g or more even if the adherend Ra is larger than the adhesive sheet of the comparative example.

Table 2

Schematic diagram of shearing force measurement method

Explanation of symbols

1: Adhesion sheet 2: Substrate 3: Adhesion layer 4: Bearon texture plate 5: Measuring table 6: Adhesive tape 7: Cardboard 8: Bar tension gauge

Claims (1)

In contact sheet provided with at least one surface adhesion layer of the base material, the adhesive layer is Ri der 80 following an Asker CSC2 hardness ASKER FP hardness 25 or more, a thickness of 10 to 100 [mu] m, and to satisfy the following requirements An adhesive sheet characterized by the above.
A: The adhesion layer is composed of a silicone composed of a linear polyorganosiloxane having vinyl groups only at both ends, a silicone composed of a linear polyorganosiloxane having vinyl groups at both ends and side chains, and only at the ends. It is obtained by crosslinking at least one silicone selected from a silicone comprising a branched polyorganosiloxane having a vinyl group and a silicone comprising a branched polyorganosiloxane having a vinyl group at the terminal and side chain.
B: The number average molecular weight of the silicone is 25,000 to 100,000.

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