JP2005297247A - Substrate for pressure-sensitive adhesive tape and pressure-sensitive adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive tape substrate for dicing which can prevent the occurrence of thread-like refuse during dicing and is excellent in uniform drawing properties to enough correspond to various expanding conditions. <P>SOLUTION: The pressure sensitive adhesive tape substrate is a multi-layer laminate in which at least a layer (A) and a layer (B) are laminated. The layer (A) is made of linear low density polyethylene having a density of 0.910-0.935. The layer (B) is made of polypropylene resins (α) and (β) and random polypropylene (γ), each having a melting point, a weight average molecular weight (Mw), and composition by a cross fractionation method in fixed ranges, respectively. The layer (B) comprises 30-50 wt.% of the polypropylene resin (α), 30-50 wt.% of the polypropylene resin (β), and the 10-50 wt.% of the random polypropylene (γ). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an adhesive tape base material and an adhesive sheet that are suitably used for dicing in which a wafer is adhesively fixed and used when dicing into a semiconductor wafer.

  Usually, a semiconductor wafer such as silicon is manufactured in a large diameter state, then diced into small pieces to form chips, and further transferred to a mounting process. At this time, the semiconductor wafer is diced in a state where it is stuck and held on the adhesive sheet, and each of the steps of cleaning, expanding, picking up, and mounting is performed. As the pressure-sensitive adhesive sheet, a sheet obtained by applying a pressure-sensitive adhesive on a base material made of a plastic film is used.

In the dicing step, the wafer is cut by a rotating round blade. For such wafer cutting, a cutting method in which the inside of the pressure-sensitive adhesive sheet holding the wafer is cut has become mainstream.
The performance of the dicing film substrate used in this dicing process is required to have uniform stretchability and excellent stretchability. That is, when the dicing film has excellent uniform stretchability, when the film is stretched, uniform gaps can be formed between the chips, so that the chip pick-up workability is extremely good. .

As a film having such performance, a dicing film using a vinyl chloride resin film as a base material has been proposed. However, since the dicing film uses a vinyl chloride resin film, there is a problem of corrosion of the wafer by chlorine ions. Furthermore, in order to give flexibility, a large amount of plasticizer is included in the film, and the plasticizer migrates to the wafer and contaminates the wafer, or migrates to the adhesive to reduce the adhesive force, and at the time of dicing There was a problem that chips were scattered.
In order to solve these problems, examples of the soft film substrate that can replace the vinyl chloride resin film include polyolefin film substrates such as polypropylene and polyethylene that do not generate harmful gases during incineration.

However, in the conventional polyolefin-based film substrate, for example, a film mainly composed of polypropylene has problems such as high crystallinity, inferior flexibility and stretchability as compared with a soft polyvinyl chloride film, and polyethylene. Even the film mainly composed of has a problem in its mechanical strength. Therefore, in order to improve these problems, a film or a laminated film made of a blend composition in which various olefinic materials are combined has been proposed.
For example, a laminated film having a layer composed of a resin composition mainly composed of an amorphous polyolefin having a propylene and / or butene-1 content of 50% by weight or more and a layer composed of polyethylene has been proposed. (For example, refer to Patent Document 1). However, when this laminated film is repeatedly bent or stretched, the layer mainly composed of amorphous polyolefin and the polyethylene layer may be easily peeled at the interface. In comparison, there were problems such as insufficient uniform stretchability.

  Moreover, the film which consists of a blend composition of the block copolymer which has a polypropylene and a polypropylene-ethylene random copolymer as a main component is disclosed (for example, refer patent document 2). Furthermore, there is a proposal of a film imparted with flexibility by blending polypropylene with a thermoplastic elastomer such as styrene-ethylene-butylene-styrene copolymer or ethylene propylene rubber. Although these films have improved flexibility, they may have insufficient transparency due to their compatibility with the material blended with polypropylene, and compared to soft polyvinyl chloride films. There are problems such as insufficient uniform stretchability when stretched.

Furthermore, the film is a multilayer film of at least three layers, the core layer is mainly made of polypropylene, is made of a resin having rubber elasticity and a clear melting point, and the layer in contact with the core layer is a linear low density polyethylene A film for dicing consisting of has been proposed. These films are said to be excellent in uniform expandability, have an appropriate tensile elastic modulus, and do not cause delamination (see, for example, Patent Document 3). However, these films, as dicing films, have a problem that when the film is thinned, the polyethylene resin layer on the surface layer sticks to the roll at the stage of lamination.
In the dicing process, the wafer is cut by a rotating round blade. At that time, the inside of the sheet is cut, so that the plastic film itself is melted by the frictional heat, and dicing after dicing is performed. Plastic film's own thread-like waste is generated on the line. If the thread waste adheres to the side surface of the chip or the like, it is mounted and sealed in a subsequent process as it is, and there is a problem that the reliability of the semiconductor element is remarkably lowered.
JP-A-6-927 Japanese Patent Laid-Open No. 7-300548 JP 2000-173951 A

  In view of the above problems, an object of the present invention is to provide a pressure-sensitive adhesive tape base material and pressure-sensitive adhesive sheet for dicing excellent in uniform stretchability that can sufficiently cope with various expanding conditions while preventing the generation of filamentous waste during dicing. It is to provide.

The adhesive tape substrate according to the invention of claim 1 (hereinafter referred to as the present invention 1)
A pressure-sensitive adhesive tape substrate which is a multilayer laminate in which at least the (A) layer and the (B) layer are laminated, and the (A) layer is a linear low-density polyethylene having a density of 0.910 to 0.935. The layer (B) has a melting point of 140 to 150 ° C., a weight average molecular weight (Mw) of 80,000 to 450,000, and a composition by a cross fractionation method.
The resin elution amount of 0 ° C. or more and 10 ° C. or less is 50 to 60% by weight of the total resin amount,
The resin elution amount of 10 ° C. to 70 ° C. is 10 to 20% by weight of the total resin amount,
The resin elution amount of 70 ° C. to 95 ° C. is 10 to 20% by weight of the total resin amount,
30 to 50% by weight of a polypropylene resin (α) having a composition within a range where the resin elution amount of 95 ° C. to 125 ° C. is 10 to 20% by weight of the total resin amount;
The melting point is 160 ° C. or higher, the weight average molecular weight (Mw) is 80,000 to 450,000, and the composition by the cross fractionation method is
The resin elution amount from 0 ° C. to 10 ° C. is 45 to 55% by weight of the total resin amount,
The resin elution amount at 10 ° C. to 70 ° C. is 15 to 25% by weight of the total resin amount,
The resin elution amount at 70 ° C. to 95 ° C. is 1 to 5% by weight of the total resin amount,
30 to 50% by weight of a polypropylene resin (β) having a composition within a range where the resin elution amount at 95 ° C to 125 ° C is 25 to 50% by weight of the total resin amount;
The melting point is 135 to 155 ° C., the weight average molecular weight (Mw) is 150,000 to 300,000, and the composition by the cross fractionation method is
The resin elution amount of 0 ° C. or more and 10 ° C. or less is 1 to 4% by weight of the total resin amount,
The resin elution amount of 10 ° C. to 70 ° C. is 12 to 18% by weight of the total resin amount,
The resin elution amount of 70 ° C. to 95 ° C. is 35 to 40% by weight of the total resin amount,
It consists of a polypropylene resin composition comprising 10 to 50% by weight of random polypropylene (γ) having a composition within the range where the resin elution amount of 95 ° C to 125 ° C is 40 to 50% by weight of the total resin amount. It is characterized by.

The adhesive tape substrate according to the invention of claim 2 (hereinafter referred to as the present invention 2)
A pressure-sensitive adhesive tape substrate which is a multilayer laminate in which at least the (A) layer and the (B) layer are laminated, and the (A) layer is a linear low-density polyethylene having a density of 0.910 to 0.935. The layer (B) comprises 90 to 80% by weight of the polypropylene resin composition of the present invention 1 and 10 to 20% by weight of linear low density polyethylene.

  The pressure-sensitive adhesive sheet according to the invention described in claim 3 (hereinafter referred to as the present invention 3) is characterized in that a pressure-sensitive adhesive layer is provided on the tape substrate of the present invention 1 or 2.

  In the layer (A) of the present invention, the density of the linear low-density polyethylene is limited to a range of 0.910 to 0.935. If the density is less than 0.910, uniform expandability cannot be obtained. Conversely, if it exceeds 0.935, expandability is lost.

  The linear low density polyethylene is not particularly limited, and a known linear polyethylene or polyethylene produced with a metallocene catalyst is used. As said linear polyethylene, generally ethylene-alpha-olefin copolymer, for example, ethylene-propylene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, ethylene-4 -Methyl-1-pentene copolymer, ethylene-1-heptene copolymer and the like.

  The ethylene-α-olefin copolymer may be a random copolymer or a block copolymer, and the content of ethylene in the copolymer is preferably based on the entire copolymer. It is 90 mol% or more, More preferably, it is 93-99.9 mol%. When the amount of ethylene is less than 90 mol%, that is, the amount of α-olefin is 10 mol% or more, the mechanical strength may be lowered.

  Further, the polyethylene produced with the metallocene catalyst may be an ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 10 carbon atoms. Specific examples of the α-olefin having 3 to 10 carbon atoms include propylene, butene-1, pentene-1, hexene-1, 4-methyl-1-pentene, heptene-1, octene-1, nonene-1, and decene. -1 etc. are mentioned. These α-olefins may be used alone or in combination of two or more.

  Polyethylene produced with the above metallocene catalyst can be obtained by a known production method, for example, fluidized bed gas phase polymerization in an inert gas using a metallocene catalyst system using ethylene or α-olefin as a raw material monomer. Alternatively, it is produced by stirring gas phase polymerization, slurry polymerization in an inert solvent, bulk polymerization using a monomer as a solvent, or the like.

  As the metallocene catalyst, a combination of a metallocene compound and an organoaluminum compound or an ionic compound is generally used. Specific examples of the metallocene compound include dimethylsilyl (2,4-dimethylcyclopentadienyl) (3 ′, 5′-dimethylcyclopentadienyl) zirconium dichloride, dimethylsilyl (2,4-dimethylcyclopentadienyl). ) (3 ′, 5′-dimethylcyclopentadienyl) hafnium dichloride and other silicon-bridged metallocene compounds, ethylenebisindenylzirconium dichloride, indenyl-based bridged metallocene compounds such as ethylenebisindenylhafnium dichloride, and the like.

  Examples of the organoaluminum compound include linear or cyclic polymers represented by the general formula (—Al (R) O—) n such as methylalumoxane, ethylalumoxane, and isobutylethylalumoxane (wherein, R is a hydrocarbon group having 1 to 10 carbon atoms, including those partially substituted with a halogen atom or RO group, and n is the degree of polymerization, preferably 5 or more, more preferably 10 or more). Or a trialkyl aluminum, a dialkyl halogeno aluminum, etc. are mentioned.

  The ionic compound is represented by the general formula C + · A-, where C + is an organic compound, an organic metal compound, an oxidizing cation of an inorganic compound, or a Bronsted acid composed of a Lewis base and a proton. And can react with the anion of the metallocene ligand to produce a metallocene cation. Specific examples thereof include ionic compounds of a tetrakis (pentafluorophenyl) borate anion and a triphenylcarbonium cation or a dialkylanilinium cation.

  In the layer (B) of the present invention, the polypropylene resin (α) has a melting point of 140 to 150 ° C. and Mw in the range of 80,000 to 450,000. When Mw is lower than this range, or conversely high, it becomes difficult to form a multilayer laminate. The Mw can be measured, for example, using a high temperature GPC (150 CV) manufactured by WATERS.

In addition, the polypropylene resin (α) has a composition by a cross fractionation method,
The resin elution amount of 0 ° C. or more and 10 ° C. or less is 50 to 60% by weight of the total resin amount,
The resin elution amount of 10 ° C. to 70 ° C. is 10 to 20% by weight of the total resin amount,
The resin elution amount of 70 ° C. to 95 ° C. is 10 to 20% by weight of the total resin amount,
It is necessary that the resin elution amount of 95 ° C. to 125 ° C. is within the range of 10 to 20% by weight of the total resin amount.

In the present invention, the measurement of the resin elution amount by the cross fractionation method can be performed as follows.
First, after dissolving the polypropylene resin in o-dichlorobenzene at a temperature of 140 ° C. or the temperature at which the polypropylene resin is completely dissolved, it is cooled at a constant rate, and the thin polymer layers are ordered in descending order of crystallinity and molecular weight. It is formed on the surface of an inert carrier prepared in advance. Next, the generated polymer layer is heated continuously or stepwise, the concentration of the components eluted in sequence is detected, and the composition distribution (crystallinity distribution) is measured (temperature rising elution fractionation). At the same time, the molecular weight and molecular weight distribution of the eluted component are measured by high temperature GPC. For this measurement, for example, a cross fractionation chromatograph apparatus (Mitsubishi Oil Chemical Co., Ltd.) equipped with the above-described temperature rising elution fractionation (TREF) part and high temperature GPC (SEC: Size Extraction Chromatography) part as a system. CFC-T150A type) can be used.

  In the layer (B) of the present invention, the polypropylene resin (β) has a melting point of 160 ° C. or higher and Mw in the range of 80,000 to 450,000. When Mw is lower than this range, or conversely high, it becomes difficult to form a multilayer laminate.

In addition, the polypropylene resin (β) has a composition by a cross fractionation method,
The resin elution amount from 0 ° C. to 10 ° C. is 45 to 55% by weight of the total resin amount,
The resin elution amount at 10 ° C. to 70 ° C. is 15 to 25% by weight of the total resin amount,
The resin elution amount at 70 ° C. to 95 ° C. is 1 to 5% by weight of the total resin amount,
It is necessary to have a composition within a range where the resin elution amount at 95 ° C. to 125 ° C. is 25 to 50% by weight of the total resin amount.

  In the layer (B) of the present invention, the random polypropylene (γ) has a melting point of 135 to 155 ° C. and an Mw of 150,000 to 300,000. When Mw is lower than this range, or conversely high, it becomes difficult to form a multilayer laminate.

In addition, the random polypropylene (γ) has a composition by a cross fractionation method,
The resin elution amount of 0 ° C. or more and 10 ° C. or less is 1 to 4% by weight of the total resin amount,
The resin elution amount of 10 ° C. to 70 ° C. is 12 to 18% by weight of the total resin amount,
The resin elution amount of 70 ° C. to 95 ° C. is 35 to 40% by weight of the total resin amount,
It is necessary to have a composition within a range where the resin elution amount of 95 ° C. to 125 ° C. is 40 to 50% by weight of the total resin amount.

  In the composition by the cloth fractionation method according to the present invention, the amount of resin elution at 0 ° C. or more and 10 ° C. or less is less than the range of the present invention, and the tape base material lacks flexibility. A sufficient strength as a material cannot be obtained. If the resin elution amount at 10 ° C. and 70 ° C. is less than the range of the present invention, the tape substrate lacks flexibility, and conversely, if it exceeds the range of the present invention, the tape substrate has poor stretchability. If the resin elution amount of 70 ° C. to 95 ° C. is less than the range of the present invention, the tape substrate is inferior in stretchability. Conversely, if it exceeds the range of the present invention, sufficient strength as a tape substrate cannot be obtained. Resin elution amount above 95 ° C and below 125 ° C If the resin elution amount is less than the range of the present invention, sufficient strength as a tape base material cannot be obtained. Conversely, if it exceeds the range of the present invention, the flexibility of the tape base material Inferior to

  In the polypropylene resin (α), polypropylene resin (β), and polypropylene resin (γ) used in the present invention, the melting point, molecular weight, and elution amount in each temperature range of each polypropylene resin are within the above ranges. This is very important in controlling physical properties such as the elastic modulus, strength, heat resistance, and secondary workability of the tape substrate.

  In the first aspect of the present invention, the (A) layer is made of linear low density polyethylene having a density of 0.910 to 0.935, and the (B) layer is made of 30 to 50% by weight of polypropylene resin (α) and polypropylene. It is characterized by comprising a polypropylene resin composition comprising 30-50% by weight of a resin-based resin (β) and 10-50% by weight of a random polypropylene (γ). By adopting such a configuration, it is possible to improve the stretchability of the entire dicing film and the tensile strength as a tape, and to prevent the generation of filamentous waste during dicing.

  Moreover, in this invention 2, (A) layer consists of a linear low density polyethylene with a density of 0.910-0.935, and (B) layer is 30-50 weight% of polypropylene-type resin ((alpha)). And polypropylene resin composition (β) 30 to 50 wt% and random polypropylene (γ) 10 to 50 wt% polypropylene resin composition 90 to 80 wt% and linear low density polyethylene 10 to 20 wt% It is characterized by the following. By adopting such a configuration, it is possible to improve the stretchability of the entire dicing film and the tensile strength as a tape, and to prevent the generation of filamentous waste during dicing. In particular, by containing the linear low-density polyethylene in the above range, generation of filamentous waste during dicing can be more effectively prevented.

  The adhesive tape base material according to the present invention is used for a dicing film that is adhesively fixed to a wafer when dicing a semiconductor wafer, and the thickness of the tape base material is not particularly limited. In general, the thickness is preferably about 0.05 to 0.5 mm, more preferably about 0.08 to 0.3 mm. If the thickness of the tape substrate is too thick, the tensile stress increases, and a large force tends to be required to stretch the tape substrate. If the tape substrate is too thin, the tensile strength tends to decrease and it tends to break. is there.

  Although it does not specifically limit as a shaping | molding method of the adhesive tape base material by this invention, It is good to shape | mold using the coextrusion method with which a manufacturing process is simple, a calendar method, and a coextrusion inflation method.

  In the adhesive tape substrate according to the present invention, at least one surface layer can be embossed in a satin finish. The dicing film substrate obtained by the present invention is stretched by being pressed against an expander ring after the chip is diced. At that time, since the film may be stretched locally by sliding between the film and the expander ring, the adhesive tape substrate of the present invention is slippery with the expander ring by embossing one surface. Can be made uniform.

  The pressure-sensitive adhesive sheet according to the present invention 3 is characterized in that a pressure-sensitive adhesive layer is provided on the pressure-sensitive adhesive tape substrate of the first or second invention.

  The pressure-sensitive adhesive layer is not particularly limited, and various known or commonly used pressure-sensitive adhesives such as rubber-based, acrylic-based, silicone-based, and polyvinyl ether-based pressure-sensitive adhesives can be used. The pressure-sensitive adhesive is preferably an acrylic pressure-sensitive adhesive, and the acrylic polymer that is a base polymer of the pressure-sensitive adhesive is usually a (meth) acrylic acid alkyl ester {(meth) acrylic acid alkyl ester and Means acrylic acid alkyl ester or methacrylic acid alkyl ester. } Or a copolymer with a copolymerizable monomer is used. The main monomer of the acrylic polymer is preferably a (meth) acrylic acid alkyl ester whose homopolymer has a glass transition temperature of −50 ° C. or lower.

  Examples of the alkyl ester of the (meth) acrylic acid alkyl ester include methyl ester, ethyl ester, butyl ester, 2-ethylhexyl ester, octyl ester, and isononyl ester. Examples of the copolymerizable monomer include hydroxyalkyl esters of (meth) acrylic acid (eg, hydroxyethyl ester, hydroxybutyl ester, hydroxyhexyl ester, etc.), (meth) acrylic acid glycidyl ester, (meth) acrylic acid, Itaconic acid, maleic anhydride, (meth) acrylic acid amide, (meth) acrylic acid N-hydroxymethylamide, (meth) acrylic acid alkylaminoalkyl ester (for example, dimethylaminoethyl methacrylate, t-butylaminoethyl methacrylate, etc.) , Vinyl acetate, styrene, acrylonitrile and the like.

  In addition, as the above-mentioned pressure-sensitive adhesive, a radiation-curing pressure-sensitive adhesive or a heat-foaming pressure-sensitive adhesive that can be cured by ultraviolet rays, electron beams, or the like can be used. Is preferred. Furthermore, an adhesive that can be used for dicing and die bonding may be used. In addition, when using a radiation curing type adhesive as an adhesive, since the radiation is irradiated to an adhesive layer before or after a dicing process, the said tape base material has sufficient radiolucency Is preferred.

  The radiation curable pressure-sensitive adhesive generally comprises the base polymer (acrylic polymer) and a radiation curable component. The radiation curing component is not particularly limited as long as it is a monomer, oligomer or polymer having a carbon-carbon double bond in the molecule and curable by radical polymerization. For example, trimethylolpropane tri (meth) acrylate, Such as pentaerythritol tri (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. Esterified product of (meth) acrylic acid and polyhydric alcohol; ester acrylate oligomer; 2-propenyl di-3-butenyl cyanurate, 2-hydroxyethylbis (2-acryloxyethyl) isocyanurate, tris (2-methacryloxy) Chill) isocyanurate or isocyanurate compounds such as isocyanurate.

  In the radiation curable pressure-sensitive adhesive, a radiation curable polymer having a carbon-carbon double bond in the polymer side chain can also be used as the base polymer (acrylic polymer). There is no need to add a radiation curable component.

  When the radiation curable pressure-sensitive adhesive is cured by ultraviolet rays, a photopolymerization initiator is required, and the radiation curable pressure-sensitive adhesive further includes a crosslinking agent, a tackifier, a filler, and aging as necessary. Conventional additives such as an inhibitor and a colorant can be contained.

Examples of the photopolymerization initiator include benzoin alkyl ethers such as benzoin methyl ether, benzoin propyl ether, and benzoin isobutyl ether; aromatic ketones such as benzyl, benzoin, benzophenone, and α-hydroxycyclohexyl phenyl ketone; Aromatic ketals such as polyvinyl benzophenone; thioxanthones such as chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, and diethylthioxanthone.
Moreover, as said crosslinking agent, a polyisocyanate compound, a melamine resin, a urea resin, an aziridine compound, an epoxy resin, an anhydrous compound, a polyamine, a carboxyl-containing polynomer etc. are mentioned, for example.

  Although the thickness of the said adhesive layer can be suitably determined with the kind of adhesive, Preferably it is 1-100 micrometers, More preferably, it is 3-50 micrometers.

  When applying the pressure-sensitive adhesive layer, a separator may be used as needed for label processing or to smooth the pressure-sensitive adhesive layer. Examples of the constituent material of the separator include paper and synthetic resin films such as polyethylene, polypropylene, and polyethylene terephthalate. Moreover, in order to improve the peelability from the pressure-sensitive adhesive layer, the surface of the separator may be subjected to a peeling treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment as necessary. Furthermore, the thickness of this separator becomes like this. Preferably it is 10-200 micrometers, More preferably, it is 25-100 micrometers.

  The pressure-sensitive adhesive tape substrate and pressure-sensitive adhesive sheet according to the present invention have the above-described configuration, are excellent in uniform stretchability, have an appropriate tensile strength, and can prevent generation of thread-like waste during dicing. It is suitably used as a substrate film, dicing tape or the like. In addition, it can also be used for surface protective films, masking films for various substrates, table cloths, building substrate films, stretch films, medical tape raw materials, and the like.

  In order to describe the present invention in more detail, examples will be given below, but the present invention is not limited to these examples.

(Example 1, Comparative Examples 1 and 2)
1. Production of Adhesive Tape Base Material A linear polyethylene having a density of 0.932 and a melt flow rate (MFR) 3 is used as an inner and outer layer, and a polypropylene resin (α), a polypropylene resin (β) having the composition shown in Table 1, And a polypropylene resin composition in which random polypropylene (γ) is blended in the proportions shown in Table 2, using a T-die extruder as a central layer, a multilayer so that the layer thickness ratio is 1/3/1 After extrusion, a single-sided corona treatment was performed to produce a three-layer tape substrate having a thickness of 100 μm.

2. Preparation of pressure-sensitive adhesive sheet As a pressure-sensitive adhesive, an acrylic copolymer having a weight average molecular weight of 800,000 obtained by copolymerizing 95 parts by weight of butyl acrylate and 5 parts by weight of acrylic acid in a conventional manner in ethyl acetate is contained. In the solution, 60 parts by weight of dipentaerythritol hexaacrylate (trade name “Kayarad DPHA”, manufactured by Nippon Kayaku Co., Ltd.), 3 parts by weight of radical polymerization initiator (trade name “Irgacure 651”, manufactured by Ciba Specialty Chemicals) An acrylic ultraviolet curable pressure-sensitive adhesive solution is prepared by adding 5 parts by weight of a polyisocyanate compound (trade name “Coronate L”, manufactured by Nippon Polyurethane Co., Ltd.). It was applied to the corona-treated surface of the tape base material obtained in the above and heated and crosslinked at 80 ° C. for 10 minutes to form a 10 μm-thick UV curable pressure-sensitive adhesive layer. Next, a separator was bonded to the surface of the pressure-sensitive adhesive layer to produce a pressure-sensitive adhesive sheet.

3. Performance evaluation The performance (dicing property, expandability, and delamination) of the pressure-sensitive adhesive sheet obtained above was evaluated by the following method. The results are shown in Table 2.

(1) Evaluation of dicing property A 6-inch wafer having a thickness of 350 μm was mounted on the dicing adhesive sheet obtained in the above step, and dicing was performed.
Blade rotation speed: 30,000 rpm
Dicing speed: 100mm / sec
Dicing depth: 40μm
Blade thickness: 50 μm
Dicing size: 5mm x 5mm
After dicing, in the case of an ultraviolet curable pressure sensitive adhesive sheet, ultraviolet rays were irradiated (460 mJ / cm ² ), and then the semiconductor chip was peeled off. The state of occurrence of filamentous debris on the sheet surface after peeling was observed using an optical microscope, the number was counted for each size of filamentous debris, and a pass / fail decision was made according to the following criteria.
Acceptance criteria Lint of less than 150μ 50 or less Lint of less than 150-500μ 10 or less Yarn of 500μ or more 0

(2) Expandability evaluation The pressure-sensitive adhesive sheet diced in the above (1) was expanded in the expanding step to evaluate whether it could be expanded uniformly. This expandability is represented by a value (X / Y) obtained by dividing the semiconductor chip interval X in the vertical direction by the semiconductor chip interval Y in the horizontal direction. The closer this value is to 1.0, the more uniformly it expands in the XY direction. The value in the range of 0.8 to 1.2 is indicated as ◯, and the value outside the above range is indicated as ×. If it is out of this range, a pick-up mistake due to the position shift of the semiconductor chip occurs.
In the examples of the present invention, it was confirmed that even when expanded at normal temperature, the constituent molecules were not stretched and oriented even when expanded.

(3) Evaluation for delamination Using the pressure-sensitive adhesive sheet diced in (1) above, when 10 chips were picked up, the number of films with a part of the film adhered to the back side of the chip was examined, and no adhesion occurred. An evaluation was given as ◯ for one, Δ for one attached, and × for two or more attached.

(Comparative Example 3)
A single-layer adhesive tape base material made only of polypropylene resin (MFR3, ethylene content 1.5%, random polypropylene) is hard and has a low elongation rate, and cannot function as an adhesive tape base material for dicing. It was a thing.

(Comparative Example 4)
A single-layer adhesive tape base material made only of an ethylene copolymer resin (EVA) is too soft and low in strength, tears, and exhibits a function as an adhesive tape base material for dicing. It was something that could not be done.

Claims (3)

A pressure-sensitive adhesive tape substrate which is a multilayer laminate in which at least the (A) layer and the (B) layer are laminated, and the (A) layer is a linear low-density polyethylene having a density of 0.910 to 0.935. The layer (B) has a melting point of 140 to 150 ° C., a weight average molecular weight (Mw) of 80,000 to 450,000, and a composition by a cross fractionation method.
The resin elution amount of 0 ° C. or more and 10 ° C. or less is 50 to 60% by weight of the total resin amount,
The resin elution amount of 10 ° C. to 70 ° C. is 10 to 20% by weight of the total resin amount,
The resin elution amount of 70 ° C. to 95 ° C. is 10 to 20% by weight of the total resin amount,
30 to 50% by weight of a polypropylene resin (α) having a composition within a range where the resin elution amount of 95 ° C. to 125 ° C. is 10 to 20% by weight of the total resin amount;
The melting point is 160 ° C. or higher, the weight average molecular weight (Mw) is 80,000 to 450,000, and the composition by the cross fractionation method is
The resin elution amount from 0 ° C. to 10 ° C. is 45 to 55% by weight of the total resin amount,
The resin elution amount at 10 ° C. to 70 ° C. is 15 to 25% by weight of the total resin amount,
The resin elution amount at 70 ° C. to 95 ° C. is 1 to 5% by weight of the total resin amount,
30 to 50% by weight of a polypropylene resin (β) having a composition within a range where the resin elution amount at 95 ° C to 125 ° C is 25 to 50% by weight of the total resin amount;
The melting point is 135 to 155 ° C., the weight average molecular weight (Mw) is 150,000 to 300,000, and the composition by the cross fractionation method is
The resin elution amount of 0 ° C. or more and 10 ° C. or less is 1 to 4% by weight of the total resin amount,
The resin elution amount of 10 ° C. to 70 ° C. is 12 to 18% by weight of the total resin amount,
The resin elution amount of 70 ° C. to 95 ° C. is 35 to 40% by weight of the total resin amount,
It consists of a polypropylene resin composition comprising 10 to 50% by weight of random polypropylene (γ) having a composition within the range where the resin elution amount of 95 ° C to 125 ° C is 40 to 50% by weight of the total resin amount. Adhesive tape substrate characterized by   A pressure-sensitive adhesive tape substrate which is a multilayer laminate in which at least the (A) layer and the (B) layer are laminated, and the (A) layer is a linear low-density polyethylene having a density of 0.910 to 0.935. A pressure-sensitive adhesive tape substrate, wherein the layer (B) comprises 90 to 80% by weight of the polypropylene resin composition according to claim 1 and 10 to 20% by weight of linear low-density polyethylene.   A pressure-sensitive adhesive sheet, wherein a pressure-sensitive adhesive layer is provided on the tape base material according to claim 1.