JPH01251737A - Adhesive sheet for fixing semiconductor wafers - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an adhesive sheet for fixing a semiconductor wafer, which is used when cutting and separating a semiconductor wafer into small element pieces.

(Prior art) Semiconductor wafers such as silicon and gallium arsenide are manufactured in a large diameter state, and while attached to adhesive sheets, are cut into small element pieces (dicing), cleaned, dried, expanded, picked up, Each step of mounting is added. The adhesive sheet used in the process from dicing to pick-up must have sufficient adhesive strength to prevent the cut element pieces from scattering or falling off during dicing with a rotating round blade or cleaning with high-pressure water. (2) have a sufficiently low adhesive strength to be easily picked up after extraction, and are required to have contradictory performance such that the adhesive does not transfer to the small pieces of the element during pickup. However, the conventionally used adhesive sheets for fixing semiconductor wafers cannot sufficiently meet these conflicting demands, and some of the cut element pieces fall off or scatter, resulting in a low yield. There were many. Furthermore, in recent years, the degree of integration of semiconductor devices has increased, and the size of device chips has tended to increase, making it even more difficult to fully satisfy these conflicting demands.

Therefore, before radiation irradiation, that is, in the process from dicing to expanding, the adhesive strength is sufficient to prevent the cut element pieces from scattering, and the adhesive strength is reduced to the extent that they can be easily picked up by radiation irradiation. A method of pink amplification after radiation irradiation using a radiation-curable adhesive was proposed. However, with this method, the adhesive tends to transfer to the small pieces of the element during pickup, the curing does not proceed sufficiently if the wafer surface is rough due to oxygen inhibition, and the new technology requires radiation irradiation between expanding and pickup. The addition of additional steps made the process more complicated, and there were drawbacks, such as the fact that conventional lines could no longer be used as they were.

(Problems to be Solved by the Invention) The present inventors provided a radiation-curable adhesive layer on a sheet-like base material, and attached semiconductor elements to an adhesive sheet for fixing a semiconductor wafer, which was cured in a pattern by radiation irradiation. Paste and
After passing through each process of dicing, washing, and drying, the product is expanded in the expanding process, from dicing to drying.

Due to the tackiness of the uncured portion of the radiation-curable adhesive layer.

Small pieces of the cut element are scattered or fallen off.

In the next process of expanding, the non-adhesive cured portion of the radiation-curable adhesive layer in the adhesive sheet does not expand, and only the adhesive uncured portion stretches, causing the sheet to swell in that area, and that area becomes the element. The present invention was achieved by discovering that it is possible to easily pick up the cut element pieces by separating them from the small pieces.9 The present invention improves the various drawbacks of the above-mentioned conventional adhesive sheets for fixing semiconductor wafers.

In the process from dicing to drying, the adhesive strength is sufficient to prevent the cut element pieces from scattering or falling off, and expanding reduces the adhesive strength so that they can be easily picked up. To provide a pressure-sensitive adhesive sheet for identifying semiconductor wafers which has the following properties and prevents the pressure-sensitive adhesive from adhering to small element pieces when picked up.

[Structure of the invention]

(Means for Solving the Problems) The present invention is an adhesive sheet for fixing semiconductor wafers used when cutting and separating semiconductor wafers into small element pieces, which comprises a radiation-curable acrylic adhesive layer on a sheet-like base material. This is an adhesive sheet for fixing a semiconductor wafer, in which the adhesive layer is cured in a pattern by radiation irradiation.

In the present invention, the sheet-like base material includes polyethylene such as linear low-density polyethylene, polypropylene, polyvinyl chloride, and polyethylene terephthalate.

Polybutylene terephthalate, polybutene, polybutadiene, polyurethane, polymethylpentene, ethylene-
A sheet of material such as vinyl acetate copolymer can be used. Among these, it is preferable to use a crosslinked polyolefin sheet as the sheet-like base material in order to prevent the sheet-like base material from elongating or bending during dicing.

The radiation-curable acrylic adhesive is of a type that has strong adhesive strength before radiation irradiation, but is cured by radiation irradiation and its adhesive strength decreases. Such adhesives include acrylic acid alkyl ester (a), carboxyl group, hydroxyl group, and amino group.

A monomer (b) having one or more functional groups selected from a cyclic acid anhydride group, an epoxy group and an isocyanate group, and if necessary, another monomer (c) that can be copolymerized with these. It is obtained by further reacting the acrylic copolymer (C) obtained by copolymerization with a monomer (d) having a group that reacts with the above functional group and an ethylenically unsaturated double bond. The main component is an acrylic polymer having ethylenically unsaturated double bonds. As the acrylic acid alkyl ester (a), ethyl acrylate,
Examples include n-butyl acrylate, isobutyl acrylate, 2-nitylhexyl acrylate, and lauryl acrylate. Among (b), monomers having a carboxyl group include (meth)acrylic acid, cinnamic acid, itaconic acid, etc.; monomers having a cyclic acid anhydride group include maleic anhydride, itaconic anhydride, etc.
Monomers having hydroxyl groups include 2-hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate, propylene glycol mono (meth)acrylate butanediol mono (meth)acrylate Glycol mono(meth)acrylates such as
N-methylol (meth)acrylamide, allyl alcohol, etc.

In addition, the amino group is a -class or secondary amino group or a primary or secondary amino group of an acid amide, and examples of the monomer having an amino group include N-methylaminoethyl (meth)acrylate, N-ethylamino ethyl(
N-alkylaminoethyl (meth)acrylates such as meth)acrylate + N-tert-butylaminoethyl (meth)acrylate.

Examples of the monomer having an epoxy group include glycidyl (meth)acrylate, and examples of the monomer having an isocyanate group include isocyanate ethyl (meth)acrylate.

Examples include polyisocyanate groups such as (meth)acryloyl isocyanate, xylylene diisocyanate, tolylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate, in which a portion of the isocyanate group is urethanized with an ethylenically unsaturated monomer having a hydroxyl group or a carboxyl group. be able to. Other monomers (C) copolymerizable with (a) and (b) used as necessary include:
Examples include methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate, and n-butyl methacrylate, styrene, and vinyl acetate.

The above monomers (a), (b) and optionally (
The acrylic copolymer (C) obtained by copolymerizing c),
Further, a group that reacts with the functional group of the acrylic copolymer (C) and a monomer (d) having an ethylenically unsaturated double bond are reacted to obtain an acrylic polymer having an ethylenically unsaturated double bond. Such a monomer (d)
When the functional group of the acrylic copolymer (C) is a carboxyl group, it is a monomer having a hydroxyl group, an epoxy group or an isocyanate group and an ethylenically unsaturated double bond, and Q is a cyclic acid anhydride. When it is a monomer, it is a monomer that has a hydroxyl group, an epoxy group, or an isocyanate group and an ethylenically unsaturated double bond; A monomer having a double bond; (i) If it is an amino group, it is a monomer having an epoxy group or an isocyanate group and an ethylenically unsaturated double bond; (i) If it is an epoxy group, A monomer having a carboxyl group, a cyclic acid anhydride group, or an amino group and an ethylenically unsaturated double bond, and (2) if it is an isocyanate group.

It is a monomer having a carboxyl group, a cyclic acid anhydride group, a hydroxyl group, or an amino group and an ethylenically unsaturated double bond, and examples thereof include the same monomers (b) having the above functional group. Even if monomer (d) and all of the functional groups possessed by the above acrylic copolymer (C) are reacted to obtain an acrylic polymer (D>) having an ethylenically unsaturated double bond, monomer (d) and the above A part of the functional groups possessed by the acrylic copolymer (C) is reacted to obtain an acrylic polymer (A) having one or more of the above functional groups and an ethylenically unsaturated double bond. Also, it is preferable to use an acrylic polymer (A) or (D) having a molecular weight of about 100,000 to 800,000.

When the molecular weight exceeds 800,000, the viscosity of the resulting radiation-curable acrylic adhesive tends to increase.

When the obtained acrylic polymer is an acrylic polymer (A) having one or more of the above functional groups and an ethylenically unsaturated double bond, this Furthermore, a compound (B) having a group that reacts with the functional group of the acrylic polymer (A> at room temperature or by heating)
You can also add Such a compound (B) may have only one group that reacts with the functional group of the acrylic polymer (A), if the molecular weight of (B) is sufficiently large.

Usually, it has two or more groups that react with the functional groups of the acrylic polymer (A). Such a compound (B)
is appropriately selected depending on the type of functional group possessed by the acrylic polymer (A), and when the functional group possessed by the acrylic polymer (A) is a carboxyl group, an epoxy group and/or an isocyanate group. A compound having
■When it is a cyclic acid anhydride group, the compound having a hydroxyl group or an isocyanate group and/or an epoxy group is ■When it is a hydroxyl group, it has a cyclic acid anhydride group and (
or) When the compound having an isocyanate group is ■ an amino group, an epoxy group and (or) When the compound having an isocyanate group is ■ an epoxy group, a carboxy group, a cyclic acid anhydride group and an amino group. (2) When the compound having one or more of the groups is an isocyanate group, a compound having one or more of a cyclic acid anhydride group, a hydroxyl group, a carboxyl group and an amino group is selected, respectively. When the acrylic polymer (A) has two or more functional groups.

As the compound (B), a compound having two or more groups that react with two or more functional groups may be used. Specific examples of the compound (B) include bisphenol A-based epoxy resins, bisphenol F-based epoxy resins, alicyclic epoxy resins such as vinylcyclohexene dioxide, and novolanc-type epoxy resins.

Compounds having epoxy groups such as glycidyl (meth)acrylate type acrylic resins, tolylene diisocyanate, diphenylmethane diisocyanate-1''l triphenylmethane triisocyanate, trimethyl hexamethylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate.

Compounds having isocyanate groups such as isophorone diisocyanate, polymethylene polyphenylisocyanate, etc., or their terminal isocyanate group adducts, ethylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, glycerin, pentaerythritol, dipentaerythritol, bisphenol A .

Polyether polyol, polyester polyol.

Acrylic resins with hydroxyl groups, compounds with hydroxyl groups such as saponified vinyl acetate resins, phthalic anhydride, sebacic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, glycerol tris (anhydrotrimellitic anhydride) tate), compounds having a cyclic acid anhydride group such as styrene-maleic anhydride copolymer resin, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, and glutaric acid.

Isosebacic acid, sebacic acid, pimelic acid, azelaic acid, β-methyladipic acid, trimellitic acid.

Pyromellitic acid, compounds with carboxyl groups such as acrylic resins with carboxyl groups, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethylenediamine, xylylenediamine,
Polyamide compounds such as melamine, benzoguanamine, and dimer acid polyamide; amino resins such as methyl etherified methylol melamine resin and butyl etherified methylol melamine resin.

It is a compound that has an amino group, such as an acrylic resin that has an amino group. The compound (B) can also be used together with a catalyst that promotes the reaction between the acrylic polymer (A) having a functional group and the compound (B). Acrylic polymer (A)
If the reaction rate between the acrylic polymer (A) and the compound (B) is high, use a two-component type containing the component containing the acrylic polymer (A) and the component containing the compound (B), and mix the two components immediately before use. It is preferable to use it. When using the compound (B), the number of ethylenically unsaturated double bonds in the acrylic polymer (A) having a functional group is 0.1 to 20 per 10,000 molecular weight of the acrylic polymer (A>). The amount of compound (B) used varies depending on the number of functional groups that the acrylic polymer (A) has.
It should be less than 20 parts by weight relative to 0 parts by weight.

Each is preferable. On the other hand, when the compound (B) is not used, the number of ethylenically unsaturated double bonds in the acrylic polymer (A) or (D) is The number is preferably about 0.1 to 10 per 10,000.

Acrylic polymer (A) and/or (D).

Alternatively, the acrylic polymer (A) and the compound (B) may optionally contain monomers or oligomers having an ethylenically unsaturated double bond, tackifiers, etc., as long as they do not impede the performance of the pressure-sensitive adhesive sheet of the present invention. Thermoplastic resins, plasticizers, organic solvents, dyes, pigments, and inorganic fillers.

A thermal polymerization initiator, double polymerization inhibitor, etc. are added to make a radiation-curable acrylic adhesive. As monomers and oligomers with ethylenically unsaturated double bonds.

(meth)acrylic acid, methyl (meth)acrylate.

Ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc.
meth)acrylic acid alkyl ester, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, (meth)acrylic acid amide.

Glycidyl (meth)acrylate, Phenoxyethyl (meth)acrylate, Isocyanatoalkyl (meth)acrylate, N-alkylcarbamoyloxyalkyl (
meth)acrylate N-alkylcarbamoyloxydialkoxyalkyl(meth)acrylate, styrene,
α-methylstyrene, vinyl acetate.

(meth)acrylonitrile, ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylol propane tri(meth)acrylate, dipentaerythritol Hexa(meth)acrylate, Tetraethylene glycol di(meth)acrylate Polyethylene glycol di(meth)acrylate, Epoxy poly(meth)acrylate Polyurethane poly
(meth)acrylate, polyester poly(meth)acrylate.

Examples include diallyl phthalate prepolymer, unsaturated polyester, and diallyl phthalate. These monomers and oligomers are preferably used in an amount of less than 50 parts by weight based on 100 parts by weight of the acrylic polymer (A) and/or (D).

The radiation-curable acrylic pressure-sensitive adhesive thus obtained is applied to a sheet-like base material using a roll coater, knife coater, gravure coater, or the like.

If necessary, it is dried to form a radiation-curable acrylic adhesive layer. Radiation curing acrylic adhesive.

After coating on another base material, drying as necessary, and pasting the sheet base material, a radiation-curable acrylic adhesive layer is provided on the sheet base material by peeling off the other base material. You can.

After a radiation-curable acrylic adhesive layer is provided on a sheet-like base material, the adhesive layer is cured in a pattern by radiation irradiation. The radiation may be ultraviolet rays, electron beams, X-rays, or γ-rays, but ultraviolet rays or electron beams are preferably used practically. The radiation may be a laser. When ultraviolet rays are used as the radiation, it is preferable to add a photopolymerization initiator and, if necessary, a photopolymerization accelerator to the radiation-curable acrylic pressure-sensitive adhesive in order to increase curing efficiency. An example of such a photopolymerization initiator is benzophenone.

In addition to methylbenzophenone, O-benzoylbenzoic acid methyl-p-benzoin ethyl ether, etc.
irUV-EB Curing Handbook - Raw Materials Edition - J (1
December 1985, Kobunshi Publishing Series) 67-73, those listed as photoinitiators and aggravating agents, or Shinzo Yamashita, Tosuke Kaneko & I "Crosslinking Agent Handbook" (October 1985, Some photopolymerization initiators and sensitizers are described on pages 582 to 593 (published by Taiseisha).
Benzophenone, ethyl N-dimethylaminobenzoate,
Examples include dimethylethanolamine and glycine.

A mask is usually used to cure the adhesive layer in a pattern by irradiation with radiation. The pattern may be of any type, such as a polka dot shape, a lattice shape, or a mosaic pattern, but it is preferable that each pattern is smaller than the element pieces after cutting and arranged regularly. Moreover, any mask may be used as long as it can control the transmitted intensity of radiation in a pattern. For example, if the radiation is an electron beam, a metal plate with many holes punched in a pattern, or if the radiation is ultraviolet rays, a plastic film made of polyethylene, polypropylene, polyvinyl chloride, polyester, etc. Alternatively, a printing ink with low UV transmittance that contains a large amount of UV absorber or metal powder is printed on a substrate with good UV transmittance such as a sheet glass plate. It is possible to use a pattern in which portions with low ultraviolet transmittance are provided by a method such as developing a silver salt photograph. The radiation may be irradiated with the mask in close contact with the adhesive layer, or the radiation may be irradiated with the mask held close to the adhesive layer so as not to touch it. When the radiation is ultraviolet rays, the use of a mask can be replaced by using a release paper or a release sheet or a sheet-like base material provided with a patterned portion having low ultraviolet transmittance. If the radiation is ultraviolet.

The irradiation dose is usually about 10 to 100 mJ/aJ, and when the radiation is an electron beam and compound (B) is not used, the irradiation dose is usually about 5 to 5Q Mrad.
When using B), the irradiation dose is 0.05 to 50 Mr
It is about ad. Furthermore, heating can be performed before, during, or after radiation irradiation.

In particular, when the radiation-curable acrylic pressure-sensitive adhesive is composed of the acrylic polymer (A) and a compound (B) having a group that reacts with (A) when heated, heating is preferably performed.

The obtained adhesive sheet for fixing semiconductor wafers is placed on a radiation-curable acrylic adhesive layer, if necessary.

It is stored with a release paper or release sheet such as polyethylene laminate paper or release-treated plastic film tightly attached.

If a release paper or sheet is adhered to the adhesive sheet for fixing a semiconductor wafer obtained in this manner, it is peeled off, and a large-diameter semiconductor wafer is adhered to the adhesive layer of the adhesive sheet, Cutting and separating the element into small pieces (dicing)
, washing, drying, expanding, and picking up steps are added.

(Example) The present invention will be explained below with reference to Examples. In one example, 9 parts means parts by weight, and 9% means % by weight.

Synthesis Examples 1 to 3 Half of the mixture having the composition shown in Table 1 Composition (■) was heated to 80°C, the remaining half of the above mixture was added dropwise over 1 hour, and the mixture was reacted at 80°C for 6 hours to form a solid A 45.0% acrylic copolymer (C) solution was obtained.

Using each of the obtained acrylic copolymer (C) solutions,
A mixture having the composition shown in Table 1 Composition (2) was reacted at 120°C for 6 hours. 2. In Synthesis Example 1, about 50 mol% of the carboxyl groups of the acrylic copolymer (C) were glycidyl methacrylate and 2. In Synthesis Example 2, the acrylic copolymer Approximately 50 mol% of the glycidyl groups in the polymer (C) reacted with acrylic acid, and in Synthesis Example 1, almost all of the acid anhydride groups in the acrylic copolymer (C) reacted with glycidyl methacrylate. After confirmation, solutions ① to ① of an acrylic polymer having the molecular weight and ethylenically unsaturated double bond shown in Table 1 and the solid content shown in Table 1 were obtained.

The molecular weight of the acrylic polymer was determined by gel permeation chromatography (manufactured by Waters, 150-CALC/ GPC
, trade name) and determined as the weight average molecular weight in terms of polystyrene.

Table 1 Synthesis Examples 4 to 6 Table 2 Composition Half of the mixture having the composition shown in ■ was heated to 80°C, and the remaining half of the above mixture was added dropwise over 1 hour, and the mixture was allowed to react at 80°C for 6 hours. An acrylic copolymer (C) solution having a solid content of 45.0% was obtained.

Using each of the obtained acrylic copolymer (C) solutions,
The mixture having the composition shown in Table 2 Composition (■) was reacted at 80°C for 5 hours, and the disappearance of the characteristic absorption (2220 cm-') of the isocyanate group was confirmed by infrared absorption spectrum.1 The molecular weight and ethylenically unsaturated double bond shown in Table 2 Solutions ① to ① of the solid content shown in Table 2 of the acrylic polymer having the following were obtained.

The TDI-HEA adduct is produced by heating 174 parts of a tolylene diisocyanate mixture consisting of 80% of 2.4-1-lylene diisocyanate and 20% of 2.6-)lylene diisocyanate to 80°C, and adding 2-hydroxyethyl acrylate to the mixture. 116 parts and 0.0 parts of hydroquinone.
It was obtained by adding 13 parts dropwise over 2 hours and then reacting at 80°C for 3 hours.

Preparation Examples 1-8 Acrylic polymer solution obtained in Synthesis Examples 1-6 ■
Radiation-curable acrylic pressure-sensitive adhesives 1 to 2 having the compositions shown in Table 3 were obtained using 1 to 2.

In Table 9, the symbols are as follows.

TGXDA solution: 5% solution of tetraglycidyl-m-xylylene diamine (solvent: toluene/isopropyl alcohol mixed solvent) TMP-TD I adduct solution 3 moles of 2.4-)lylene diisocyanate per 1 mole of nitrimethylolpropane A 30% solution of the adduct added at a ratio of (
Solvent: ethyl acetate) Samelamine 50: Methylated melamine-based amino resin.

Manufactured by American Cyanamid, trade name GTAHTM: Glycerol tris (anhydrotrimellitate) TMPTA: I-limethylolpropane triacrylate BDEABP: 4.4''-bisdiethylaminobenzophenone (hereinafter referred to as margin) Examples 1 to 8 Thickness A sheet-like base material obtained by subjecting a polyethylene terephthalate sheet having a diameter of 50 μm to a peeling treatment was coated with radiation-curable acrylic adhesives Φ to ■ shown in Table 4 obtained in +!PI Preparation Examples 1 to 8 to a dry film thickness. After coating to a length of 108 m and drying at 100°C for 2 minutes.

A 60 μm thick polyethylene sheet was laminated on the coated surface. The obtained laminate sheet was subjected to the first step shown in Table 4, followed by the second step, and the polyethylene sheet was peeled off and stretched by 50% (expanding). Immediately after peeling off the polyethylene sheet and after 50% stretching (
Table 4 shows the results of measuring the adhesion to the stainless steel plate after expansion.

In addition, when a semiconductor wafer was attached to the polyethylene sheet after it was separated by #I and the element pieces were cut, separated, washed, and dried using a conventional method, the element pieces scattered and fell off in all sheets. Not.

Next, when expanding was performed, small element pieces could be easily picked up from any of the sheets, and no adhesive was observed to be transferred to the picked up small element pieces.

Comparative Example 1 Table 4 shows the results of measuring the adhesive strength to a stainless steel plate in the same manner as in Example 1, except that the mask ① was not used and the heating as the second step of the curing step was not performed.

Comparative Example 2 Table 4 shows the results of measuring the adhesive strength to a stainless steel plate in the same manner as in Example 2, except that the mask -A was not used and no ultraviolet irradiation was performed.

The symbols in Table 2 and 4 are as follows.

(1) Curing step EB: A mask was brought into close contact with the surface of the polyethylene terephthalate sheet of the laminate sheet, and an electron beam was irradiated from the mask side at the irradiation dose (unit: Mrad) described in parentheses, and then the mask was removed.

Uv: A mask was brought into close contact with the surface of the polyethylene terephthalate sheet of the laminate sheet, and ultraviolet rays were irradiated from the mask side at the exposure dose (unit: m J /ci) described in parentheses, and then the mask was removed.

Heated at 40° C. for one week.

m: None 2) Mask ■-A: A mask with a diameter of 0.0155 nm was printed on one side of a 100 μm thick polyethylene terephthalate sheet using silver salt photography.
+, A mask with many circular patterns with a center-to-center distance of 0.3125 mm and a 50% halftone white sheet ■
The silver salt photographic side of the laminate sheet was brought into close contact with the polyethylene terephthalate sheet side of the laminate sheet.

(2)-B: The surface of the masked clear ethylene terephthalate sheet from above was brought into close contact with the polyethylene terephthalate sheet surface of the laminate sheet.

■: A hard aluminum plate with a thickness of 0.1 m and a diameter of 0.1 m.
A large number of holes of 0155m are drilled with a center opening of 111to and 3125+n.

■: A hard aluminum plate with a thickness of 0.3 fl and a diameter of 0.3 fl.
0155 Crane with many holes with a center-to-center distance of 0.3125 mm.

m: No mask.

*: Cracked and peeled off from the stainless steel plate.

(Hereinafter, blank space) [Effects of the Invention] By using the adhesive sheet for fixing semiconductor wafers of the present invention, in the process from dicing to drying, the adhesiveness of the uncured portion of the radiation-curable acrylic adhesive layer prevents cutting. Due to the expansion in the primary process, small pieces of elements were scattered or fell off.

The non-adhesive cured portion of the radiation-curable acrylic adhesive layer in the adhesive sheet does not stretch, and only the adhesive uncured portion stretches, causing the sheet in that area to tingle and detach from the element piece. As a result, the cut element pieces can be easily picked up, and the adhesive can be prevented from being transferred to the element pieces during pickup. In addition, two aspects of the present invention.

By appropriately selecting the composition of the radiation-curable acrylic adhesive, the shape of the cured pattern, the radiation dose, heating conditions, etc., the tackiness of the entire adhesive sheet before expanding can be freely controlled.

Claims (1)

[Scope of Claims] 1. An adhesive sheet for fixing a semiconductor wafer used when cutting and separating a semiconductor wafer into small element pieces, which comprises a radiation-curable acrylic adhesive layer provided on a sheet-like base material and cured by radiation irradiation. An adhesive sheet for fixing semiconductor wafers, which is made by curing the above-mentioned adhesive layer in a pattern. 2. The pressure-sensitive adhesive sheet for fixing semiconductor wafers according to claim 1, wherein the radiation-curable acrylic pressure-sensitive adhesive is mainly composed of an acrylic polymer having ethylenically unsaturated double bonds. 3. The radiation-curable acrylic adhesive has one or more functional groups selected from a carboxyl group, a hydroxyl group, an amino group, a cyclic acid anhydride group, an epoxy group, and an isocyanate group and an ethylenically unsaturated double bond. an acrylic polymer (A) having
) as a main component, and is cured by radiation and heat, according to claim 1.