JPH11323273A - Adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive sheet hardly staining the surface of a semiconductor wafer even if the sheet is stuck on the wafer, capable of providing a good distance between chip elements by expanding the sheet, and hardly causing problems of waste disposal. SOLUTION: This adhesive sheet consists of a substrate film layer and an adhesive mass layer, and the substrate film layer is composed of a laminated body constituted of (A) an olefin layer comprising (a) 30-100 wt.% amorphous polyolefin having >=50 wt.% content of propylene and/or butene-1, (b) 0-70 wt.% crystalline polypropylene-based resin and (c) 0-70 wt.% polyethylene-based resin, and (B) a polyethylene-based resin layer composed of the polyethylene-based resin such as a low density polyethylene. The tensile modulus of the adhesive mass layer is, for example, >=0.1 kgf/mm<2> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive sheet used in various semiconductor manufacturing processes and the like.

[0002]

2. Description of the Related Art Adhesive sheets are used in various processes for manufacturing semiconductors, for example, a back-grinding process for thinning a wafer on which a pattern is formed, and a process for cutting a wafer into individual patterns and dividing the wafer into semiconductor elements. In the dicing process, the dividing process of various semiconductor packages accommodating semiconductor elements, and the like, the tape is used as a semiconductor wafer fixing tape. For example, in the dicing step, when a semiconductor wafer on which a circuit pattern is formed is cut and divided into element pieces, a fixing sheet for attaching a wafer called a dicing tape is usually used to fix the wafer. Then, after the wafer is cut, the spacing between the chip elements is widened by stretching the fixed sheet by an expanding device, and the elements are picked up.

Hitherto, as the base film of the fixing sheet, many films mainly composed of polyvinyl chloride (PVC) have been put to practical use. However, since polyvinyl chloride is a chlorine-based resin and contains a stabilizer and a plasticizer made of a metal compound, chlorine ions, metal ions, and a plasticizer migrate to the semiconductor wafer, and the surface of the semiconductor wafer is removed. May cause contamination. In recent years, from the viewpoint of environmental protection, disposal of vinyl chloride resin waste has also become a major problem. On the other hand, in order to avoid the above problem, a polyolefin-based film that is a non-vinyl chloride-based film is also used as a base film of the fixing sheet. However, such a fixing sheet has a problem that a sufficient chip element interval cannot be obtained in the expanding step.

[0004]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a semiconductor device which can be attached to a semiconductor wafer without contaminating the surface of the wafer. The object of the present invention is to provide a pressure-sensitive adhesive sheet free from the problem described above.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that when the base film layer of the pressure-sensitive adhesive sheet is constituted by a laminate composed of a plurality of specific polymer layers, it can be used for semiconductor manufacturing. It was found that when used as a pressure-sensitive adhesive sheet, the surface of the wafer was not contaminated and good chip element spacing could be obtained in the stretching step, thus completing the present invention.

That is, the present invention relates to a pressure-sensitive adhesive sheet comprising a base film layer and a pressure-sensitive adhesive layer, wherein the base film layer comprises (A) (a) propylene and / or butene-1.
30 to 100% by weight of an amorphous polyolefin having a component content of 50% by weight or more, (b) 0 to 70% by weight of a crystalline polypropylene resin, and (c) 0 to 70% by weight of a polyethylene resin (B)
Provided is an adhesive sheet constituted by a laminate with a polyethylene-based resin layer constituted by a polyethylene-based resin. In addition, in this specification, the content of the x component (for example, propylene component) in the polymer means the content of the structural unit (repeating unit) corresponding to the x component.

[0007]

Embodiments of the present invention will be described below in detail. In the present invention, the base film layer is composed of a laminate of a polyolefin layer (A) and a polyethylene resin layer (B).

[Polyolefin layer (A)] The polyolefin layer (A) is composed of an amorphous polyolefin (a) of 30 to 1%.
00% by weight of the crystalline polypropylene resin (b)
70% by weight and 0 to 70% by weight of the polyethylene resin (c). When the content of the amorphous polyolefin (a) is 3
If the amount is less than 0% by weight, the film has a yield point, and is not suitable for fixing a semiconductor wafer. The content of the amorphous polyolefin (a) is preferably about 30 to 90% by weight, and more preferably about 30 to 80% by weight. The content of the crystalline polypropylene resin (b) is preferably 5 to 68% by weight, more preferably 10 to 65% by weight.
It is about. The content of the polyethylene resin (c) is preferably 1 to 50% by weight, more preferably 2 to 50% by weight.
It is about 20% by weight.

The amorphous polyolefin (a) has a propylene or butene-1 content or a total content of propylene and butene-1 of 50% by weight or more (50 to 10%).
0% by weight). The content is preferably 5
It is at least 5% by weight (55 to 100% by weight), more preferably at least 60% by weight (60 to 100% by weight). If the content is less than 50% by weight, the affinity or compatibility with the polyethylene resin layer (B) decreases.

The amorphous polyolefin (a) has a boiling point n
A polyolefin having a heptane-insoluble content (i.e., a Soxhlet-extracted insoluble content with boiling n-heptane) of 70% by weight or less, preferably 60% by weight or less. Boiling n
-When the heptane-insoluble content is more than 70% by weight, the ratio of the amorphous portion is small, and it is difficult to obtain sufficient flexibility when the adhesive sheet is used.

As the amorphous polyolefin (a), amorphous polypropylene, amorphous poly (butene-1), amorphous propylene- (butene-1) copolymer, amorphous propylene and / or Or a copolymer of butene-1 and another olefin (such as an α-olefin) [for example, propylene-ethylene copolymer, propylene- (hexene-
1)-(octene-1) terpolymer, propylene-
(Hexene-1)-(4-methylpentene-1) a copolymer of propylene and other olefins containing propylene as a main component such as a terpolymer; (butene-1) -ethylene copolymer and the like. Copolymer of butene-1 containing butene-1 as a main component and another olefin; propylene- (butene-
1) a multi-component copolymer of propylene, butene-1, and another olefin, which is mainly composed of a mixed monomer of propylene and butene-1, such as a terpolymer of ethylene;

When the amorphous polyolefin (a) is a propylene-ethylene copolymer, the content of the ethylene component is usually 0 to 30% by weight (for example, 0.1 to 30% by weight), preferably 1 to 30% by weight. It is about 20% by weight. When the content of the ethylene component is more than 30% by weight, the pressure-sensitive adhesive sheet tends to be too soft.

When the amorphous polyolefin (a) is a multi-component copolymer of propylene, butene-1 and another olefin, the content of the other olefin is less than 50% by weight (for example, 0.1%). -50% by weight), preferably 1-45.
%, More preferably about 5 to 44% by weight.

The propylene- (butene-1) copolymer has large tensile elongation, rebound resilience and cohesion, and is suitably used as the amorphous polyolefin (a). Specifically, for example, a commercially available product such as "Ubetac (trade name)" of Ube Industries, Ltd. can be used.

The amorphous polyolefin (a) may be modified. For example, the above amorphous polyolefin,
Modified with a modifier such as an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, fumaric acid, and itaconic acid and / or their esters, acid anhydrides, and metal salts. be able to. Among such modified polyolefins, maleic anhydride or itaconic anhydride, particularly a modified polyolefin modified with maleic anhydride, is preferred.

The number average molecular weight of the amorphous polyolefin (a) is, for example, 1,000 to 200,000, preferably 15
It is about 100 to 100,000. Number average molecular weight is 200
If it exceeds 000, film forming becomes difficult, and 1000
If it is less than 3, the mechanical strength tends to decrease.

As the amorphous polyolefin (a), for example, atactic polypropylene obtained as a by-product during the production of crystalline polypropylene may be used, and by appropriately setting polymerization conditions such as a polymerization catalyst,
It may be produced from propylene and used. In addition, a copolymer containing propylene and / or butene-1 as a monomer component can be produced by a target production from a monomer mixture containing two or three or more monomers in a predetermined ratio. The target production is carried out, for example, by polymerizing the raw material monomers in the presence or absence of hydrogen using a titanium-supported catalyst supported on magnesium chloride and triethylaluminum. From the viewpoint of the stability of raw material supply and the stability of quality, it is preferable to use a predetermined amorphous polyolefin produced for the purpose. In addition, if there is a corresponding suitable commercial product, a commercial product can be appropriately selected and used. The amorphous polyolefin (a) can be used alone or in combination of two or more.

The crystalline polypropylene resin (b) includes a boiling n-heptane-insoluble resin. Examples of such a resin include isotactic polypropylene which is generally commercially available for extrusion molding, injection molding, blow molding, and the like, and propylene having an isotactic structure having stereoregularity and other olefins (such as α-olefins). )). As the other olefin, for example, ethylene, butene-1, pentene-1,
Hexene-1, 4-methylpentene-1, heptene-
Examples thereof include α-olefins having about 2 to 8 carbon atoms, such as 1, octene-1 and the like. Among these, ethylene or butene-1 is particularly preferred.

Preferred crystalline polypropylene resin (b) includes propylene homopolymer;
0% by weight or less (for example, 0.1 to 30% by weight), preferably 1 to 25% by weight of a propylene-ethylene random copolymer or block copolymer;
For example, a propylene- (butene-1) random copolymer or a block copolymer containing not more than 0.1% by weight (for example, 0.1 to 20% by weight) is exemplified.

Further, the crystalline polypropylene resin (b)
May be used after being modified with a modifying agent. As the modifier, those similar to the modifier for the amorphous polyolefin (a) can be used. Preferred modifiers are maleic anhydride and itaconic anhydride, with maleic anhydride being particularly preferred.

The crystalline polypropylene resin (b) may be a commercially available product, or may be produced and used. The method for producing the crystalline polypropylene is not particularly limited, and may be appropriately selected from conventional methods for producing a crystalline polypropylene-based resin and applied. The isotactic polypropylene is usually commercially available for extrusion molding, injection molding, blow molding and the like. The crystalline polypropylene resin (b) can be used alone or in combination of two or more.

The polyethylene resin (c) includes low-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene copolymer containing ethylene as a main component, and the like. As comonomers in the ethylene copolymer, propylene, butene-1, pentene-1,
Hexene-1, 4-methylpentene-1, heptene-
1, α-olefins having about 2 to 8 carbon atoms such as octene-1; vinyl esters such as vinyl acetate; (meth) acrylates such as methyl acrylate, ethyl acrylate and methyl methacrylate; acrylic acid, methacrylic acid And the like. The content of the ethylene component in the ethylene copolymer is, for example, 5
It is at least 0% by weight, preferably at least 70% by weight, more preferably at least 80% by weight, particularly at least 90% by weight. One or more polyethylene resins (c) can be used. Preferred polyethylene resins (c) include low density polyethylene and the like.

When the polyethylene resin (c) is contained in the polyolefin layer (A), the adhesion to the polyethylene resin layer (B) can be improved. In addition, the polyolefin layer (A) may contain a resin component other than the above as long as the properties such as flexibility of the pressure-sensitive adhesive sheet are not impaired.

In the polyolefin layer (A), various additives and fillers such as a heat stabilizer, an antioxidant, a light stabilizer, an antistatic agent, a lubricant, a nucleating agent,
Flame retardants, pigments or dyes, calcium carbonate, calcium sulfate, barium nitrate, magnesium hydroxide, mica, talc, clay and the like can be added. The total amount of these additives and fillers is about 0 to 8% by weight (for example, about 0.01 to 5% by weight).

[Polyethylene Resin Layer (B)] As the polyethylene resin constituting the polyethylene resin layer (B), the resins exemplified as the polyethylene resin (c) and the like can be used. Preferred polyethylene resins include low-density polyethylene.

The polyethylene-based resin layer (B) may contain a resin other than the polyethylene-based resin, and the above-mentioned additives and fillers, as long as the properties of the resin layer are not impaired.

The content of the polyethylene resin in the polyethylene resin layer (B) is, for example, 80% by weight or more, preferably 90% by weight or more, and more preferably 95% by weight.
That is all.

[Base Film Layer] The layer structure of the base film layer is not particularly limited as long as it contains the polyolefin layer (A) and the polyethylene resin layer (B). Is formed by alternately laminating a polyolefin layer (A) and a polyethylene resin layer (B). The number of layers of the polyolefin layer (A) and the polyethylene resin layer (B) is not particularly limited, but is usually about 1 to 3 layers, respectively. The base film layer is (A) /
It is preferable to adopt the layer configuration of (B) or to configure both outer surfaces with a polyethylene resin layer (B). Examples of the layer configuration in which both outer surfaces are formed of the polyethylene resin layer (B) include, for example, (B) / (A) / (B), (B) / (A) /
(B) / (A) / (B).

In the base film layer according to the present invention,
Although the polyolefin layer (A) contributes to imparting flexibility to the entire pressure-sensitive adhesive sheet, the amorphous polyolefin used has a high surface tackiness, particularly when the molecular weight is low, the surface tackiness is remarkable. On the other hand, the polyethylene resin layer (B) hardly contributes to the flexibility of the pressure-sensitive adhesive sheet, but hardly exhibits surface tackiness. Therefore, as described above, by forming both outer surfaces with the polyethylene resin layer (B) and forming the inner layer in the thickness direction with the polyolefin layer (A), the surface adhesion on the base film layer side is reduced. Moreover, an adhesive sheet having excellent flexibility can be obtained. Further, in the case of a substrate film having a layer structure of polyolefin layer (A) / polyethylene resin layer (B), the pressure-sensitive adhesive layer is formed on the surface of the polyolefin layer (A) side, whereby An excellent pressure-sensitive adhesive sheet can be obtained.

It should be noted that another thermoplastic resin layer may be formed between adjacent layers such as between the polyolefin layer (A) and the polyethylene resin layer (B). Examples of such a resin layer include a gas barrier layer made of polyamide, polyvinyl alcohol, saponified ethylene-vinyl acetate copolymer, polyester, and the like.

The thickness of each layer constituting the base film layer is as follows:
It can be appropriately selected within a range that does not impair flexibility and the like, and is generally about 2 to 1000 μm, preferably about 3 to 300 μm, and more preferably about 5 to 200 μm. The ratio of the thickness of the polyolefin layer (A) to the thickness of the polyethylene-based resin layer (B) is not particularly limited, either. For example, the total thickness of the polyolefin layer (A) is About 20 to 99% of the total thickness of the base film layer,
In particular, it is preferable to set so as to be 30 to 95%.

The base film constituting the base film layer can be obtained by a conventional laminating method, for example, an extrusion lamination method, a co-extrusion lamination method, a dry lamination method, a thermal lamination method and the like. For example, in the coextrusion lamination method, a resin composition constituting the polyolefin layer (A) and a resin composition constituting the polyethylene resin layer (B) are melt-extruded using an extruder suitable for the number of layers, After laminating in a molten state by a conventional method such as a T-die method or an inflation method, the substrate film is obtained by cooling with a cooling means such as a cooling roll. The polyolefin layer (A)
The amorphous polyolefin (a), the crystalline polypropylene-based resin (b), the polyethylene-based resin (c), and, if necessary, the additive and the like,
It can be prepared by supplying to a kneader such as a kneader, a Banbury mixer, a roll, or the like, a single-screw or twin-screw extruder, and heat-kneading. In the thermal lamination method, the polyolefin layer (A) and the polyethylene resin layer (B)
Can be formed by extrusion molding, injection molding, compression molding or the like, and the obtained films can be laminated by heat fusion to form a base film.

The substrate film thus obtained may be subjected to a surface treatment in order to improve the coating property of the pressure-sensitive adhesive. Examples of the surface treatment include corona discharge treatment, plasma treatment, flame treatment, and acid treatment.

[Adhesive Layer] As the adhesive constituting the adhesive layer, an appropriate adhesive such as an acrylic adhesive or a rubber adhesive can be used. Above all, an acrylic pressure-sensitive adhesive containing an acrylic polymer as a main component is preferable from the viewpoints of adhesiveness to a semiconductor wafer and cleanability of the wafer after peeling with an organic solvent such as ultrapure water or alcohol.

Examples of the acrylic polymer include (meth) acrylic acid alkyl esters (for example, methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, isobutyl ester, s-butyl ester, t-butyl ester, Pentyl ester, isopentyl ester, hexyl ester, heptyl ester, octyl ester, 2-ethylhexyl ester, isooctyl ester, nonyl ester, decyl ester, isodecyl ester, undecyl ester, dodecyl ester, tridecyl ester,
1 to 1 carbon atoms such as tetradecyl ester, hexadecyl ester, octadecyl ester, and eicosyl ester
30, particularly a linear or branched alkyl ester having 4 to 18 carbon atoms), and one or more of cycloalkyl (meth) acrylates (eg, cyclopentyl ester, cyclohexyl ester, etc.). An acrylic polymer used as a monomer component is exemplified.

The acrylic polymer may be used, if necessary, to improve the cohesive strength, heat resistance and the like.
It may contain a unit corresponding to another monomer component copolymerizable with the alkyl acrylate or the cycloalkyl ester. Such monomer components include, for example, carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid; maleic anhydride, itaconic anhydride and the like. Acid anhydride monomers: 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, (meth) acrylic acid 8-hydroxyoctyl, (meth) acrylic acid 1
Hydroxyl group-containing monomers such as 0-hydroxydecyl, 12-hydroxylauryl (meth) acrylate, and (4-hydroxymethylcyclohexyl) methyl acrylate; styrene sulfonic acid, allyl sulfonic acid, 2-
Sulfonic acid group-containing monomers such as (meth) acrylamido-2-methylpropanesulfonic acid, (meth) acrylamidopropanesulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalenesulfonic acid; 2-hydroxyethylacryloyl phosphate, etc. And the like. One or more of these monomer components can be used.

Further, in the acrylic polymer, a polyfunctional monomer or the like may be used as a monomer component for copolymerization, if necessary, for the purpose of crosslinking treatment or the like. Examples of such a monomer include hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and pentaerythritol diene. Examples thereof include (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy acrylate, polyester acrylate, and urethane acrylate. One or more of these polyfunctional monomers can be used. The amount of the polyfunctional monomer to be used is preferably 30% by weight or less of the total monomer components from the viewpoint of adhesive properties and the like.

The acrylic polymer is obtained by subjecting a single monomer or a mixture of two or more monomers to polymerization. The polymerization can be performed by any method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization and the like. The pressure-sensitive adhesive layer preferably has a low content of low molecular weight substances from the viewpoint of preventing contamination of the wafer. From this point, the number average molecular weight of the acrylic polymer is preferably 300,000 or more, and more preferably about 400,000 to 3,000,000. In order to increase the number average molecular weight of the polymer, a crosslinked polymer crosslinked by an appropriate method such as an internal crosslinking method or an external crosslinking method can also be used.

By adding a radiation-curable monomer component to the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer can be composed of a radiation-curable pressure-sensitive adhesive. Examples of such a monomer include urethane (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, Pentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,
4-butanediol di (meth) acrylate and the like. The amount of the monomer is, for example, 5 to 500 parts by weight, preferably about 70 to 150 parts by weight, based on 100 parts by weight of the main polymer constituting the pressure-sensitive adhesive.

As a photopolymerization initiator used for curing a mixture containing the above-mentioned radiation-curable monomer component by ultraviolet rays or the like, for example, 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ) Ketones, α-hydroxy-α, α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone,
Α- such as hydroxycyclohexyl phenyl ketone
Ketol compounds; methoxyacetophenone, 2,2-
Dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1- [4- (methylthio) -phenyl] -2-morpholinopropane-1
Benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether and anisoin methyl ether; ketal compounds such as benzyl dimethyl ketal; aromatic sulfonyl chloride compounds such as 2-naphthalene sulfonyl chloride; Photoactive oxime compounds such as phenone-1,1-propanedione-2- (o-ethoxycarbonyl) oxime; benzophenone compounds such as benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone; thioxanthone ,
2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,
Thioxanthone compounds such as 4-diethylthioxanthone and 2,4-diisopropylthioxanthone; camphorquinone; halogenated ketones; acylphosphinoxides; acylphosphonates.

The tensile modulus of the pressure-sensitive adhesive layer is 0.1 kgf
/ Mm ² or more, more preferably,
It is about 0.5 to 100 kgf / mm ² . If the tensile modulus of the pressure-sensitive adhesive layer is less than 0.1 kgf / mm ² , problems such as contamination of the wafer when the pressure-sensitive adhesive sheet is separated from the semiconductor wafer are likely to occur. The tensile elastic modulus is determined according to JIS
It can be measured according to K 7113.

The adhesive strength of the pressure-sensitive adhesive layer can be appropriately set according to the purpose of use, etc., but generally, the adhesive strength to the stainless steel plate (SUS304 BA) is considered from the viewpoint of maintaining the adhesion to the semiconductor wafer and peeling off from the wafer. Force (normal temperature, 1
(80 ° peel value, peeling speed 300 mm / min), for example, 2000 g / 20 mm or less, and preferably 15 g / 20 mm or less.
It is about 1000 g / 20 mm.

Although the thickness of the pressure-sensitive adhesive layer may be determined as appropriate,
Generally 1 to 300 μm, preferably 3 to 200 μm,
More preferably, it is about 5 to 100 μm.

[Production of pressure-sensitive adhesive sheet] The pressure-sensitive adhesive sheet of the present invention can be prepared by a conventional method, for example, a pressure-sensitive adhesive, and if necessary,
It can be produced by coating a coating liquid containing the additive, the crosslinking agent, the photopolymerization initiator and the like on the base film and subjecting it to a curing treatment as required. Alternatively, it can also be produced by applying the coating liquid on a suitable separator (such as release paper) to form an adhesive layer, and transferring (transferring) this onto the base film. Furthermore, depending on the type of the adhesive, the resin composition constituting the polyolefin layer (A), the resin composition constituting the polyethylene resin layer (B), and the adhesive layer constituting the It can also be manufactured by co-extrusion with a pressure-sensitive adhesive composition using a co-extrusion molding machine.

The pressure-sensitive adhesive sheet thus obtained is excellent in flexibility and has a high elongation when stretched. Further, since it does not substantially contain a chlorine component or a metal component, it does not contaminate the adherend. Therefore, it can be suitably used as an adhesive sheet for attaching a semiconductor wafer (for example, an adhesive sheet for dicing).

[0046]

According to the pressure-sensitive adhesive sheet of the present invention, when a semiconductor wafer is bonded and fixed, the surface of the wafer is not contaminated, and good chip element spacing can be obtained by extension. Further, there is no problem of waste treatment such as a vinyl chloride film.

[0047]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 Amorphous polyolefin (a1) having a propylene content of 65% by weight, a butene-1 content of 35% by weight, a number average molecular weight Mn of 6,500, and a boiling n-heptane insoluble content of 5% by weight or less (trade name) : Ubetac UT2780, manufactured by Ube Industries, Ltd.)
40 parts by weight, density 0.90 g / cm ³ , melt flow rate (MFR) (230 ° C.) = 1.0 g / 10 min crystalline polypropylene (b1) (trade name: F-221, Inc.)
60 parts by weight of ground polymer) and density of 0.92 g
/ Cm ³ , melt flow rate (MFR) (190 ° C)
= 7.0 g / 10 min. Of low-density polyethylene (c1) (trade name: L719, manufactured by Ube Industries, Ltd.)
The mixture was supplied to a Brabender kneader equipped with a die and melt-mixed at 200 ° C. to obtain a resin composition. This resin composition was press-molded at a pressing temperature of 200 ° C., a pressing pressure of 50 kgf / cm ² , a preheating time of 5 minutes, and a pressing time of 1 minute to obtain a film (A) having a thickness of about 80 μm. On the other hand, density 0.92
g / cm ³ , melt flow rate (MFR) (190
C) = 7.0 g / 10 min., Low-density polyethylene (trade name: L719, manufactured by Ube Industries, Ltd.) is supplied to the above-mentioned Brabender kneader, and is extruded to form a film (B) having a thickness of about 10 μm. I got The film (B) is laminated on both sides of the film (A), at a temperature of 200 ° C. and a pressure of 1 kgf /
The substrate was heat-fused under the condition of cm ² to prepare a base film.

A composition comprising 70 parts by weight of methyl acrylate, 30 parts by weight of butyl acrylate, and 5 parts by weight of acrylic acid was copolymerized in toluene to give a number average molecular weight of 3
Thus, a 00000 toluene solution of an acrylic copolymer was obtained. The acrylic copolymer 10 was added to this toluene solution.
A pressure-sensitive adhesive composition was prepared by adding and mixing 70 parts by weight of a urethane oligomer, 5 parts by weight of a polyisocyanate compound, and 5 parts by weight of a photopolymerization initiator with respect to 0 parts by weight. The pressure-sensitive adhesive composition obtained above was applied to one surface of the substrate film, and a pressure-sensitive adhesive layer having a thickness of 10 μm was formed to obtain a pressure-sensitive adhesive sheet. The pressure-sensitive adhesive layer of this pressure-sensitive adhesive sheet had a tensile modulus of elasticity of 10 kgf / mm ² , and had an adhesive force to a stainless steel plate (SUS304 BA) (normal temperature, 1 ° C).
(80 ° peel value, peeling speed 300 mm / min) was 400 g / 20 mm. A semiconductor wafer was bonded to the adhesive surface of the adhesive sheet thus obtained, diced under the conditions described below, cut into individual chips, and then subjected to band extraction under the following conditions.

When the width of the cut groove between the chips (interval between the chips), which was widened by the ex-band, was measured.
μm. [Dicing conditions] Dicing apparatus: 2S / 8 made by DISCO Dicing speed: 100 mm / s Dicing blade: 2050HFDD (made by DISCO) Dicing blade rotation speed: 40000 rpm Dicing tape cutting depth: 30 μm Chip size: 10 mm × 10 mm Wafer size: 6 Inch [Expanding condition] Dicing ring: 2-6-1 (Disco, inner diameter 1
9.5 cm) Withdrawal amount: 10 mm Die bonder: CPS-100 (manufactured by NEC Kikai Co., Ltd.) Example 2 Amorphous polyolefin (a1), crystalline polypropylene (b1), and crystalline polypropylene (b1) for producing film (A) The amount of the low-density polyethylene (c1) was adjusted to 50 parts by weight,
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1, except that 0 parts by weight and 3 parts by weight were used. Using this adhesive sheet, the distance between chips was measured in the same manner as in Example 1,
It was 300 μm. In addition, the tensile elasticity of the pressure-sensitive adhesive layer of the obtained pressure-sensitive adhesive sheet was 10 kgf / mm ² , and the adhesive force was an adhesive force to a stainless steel plate (SUS304BA) (normal temperature, 180 ° peel value, peeling speed 300 mm / m).
in) was 400 g / 20 mm.

Comparative Example 1 The amounts of the amorphous polyolefin (a1), the crystalline polypropylene (b1), and the low-density polyethylene (c1) used to prepare the film (A) were 25 parts by weight and 7 parts by weight, respectively.
An adhesive sheet was obtained in the same manner as in Example 1 except that the amount was 5 parts by weight and 3 parts by weight. Using this adhesive sheet, the distance between chips was measured in the same manner as in Example 1,
It was 100 μm.

Comparative Example 2 A density of 0.92 g / cm ³ and a melt flow rate (MF
R) (190 ° C.) = Except that a film (thickness: 100 μm) obtained by extrusion molding a low-density polyethylene (trade name: F200, manufactured by Ube Industries, Ltd.) of 20 g / 10 minutes was used as the base film. A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1. Using this pressure-sensitive adhesive sheet, the distance between the chips was measured in the same manner as in Example 1.
m.

Claims (2)

[Claims] 1. An adhesive sheet comprising a base film layer and a pressure-sensitive adhesive layer, wherein the base film layer comprises (A)
(A) 30 to 100 amorphous polyolefins having a propylene and / or butene-1 component content of 50% by weight or more.
% By weight, and (b) a crystalline polypropylene resin
An adhesive sheet comprising a laminate of a polyolefin layer containing 0 to 70% by weight of (c) a polyethylene resin and (B) a polyethylene resin layer made of a polyethylene resin. 2. The pressure-sensitive adhesive layer has a tensile modulus of 0.1 kgf.
The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive sheet has a ratio of / mm ² or more.