TWI507502B - Semiconductor wafer processing adhesive sheet - Google Patents

Description

Adhesive sheet for semiconductor wafer processing

The present invention relates to a semiconductor wafer processing adhesive sheet having a radiation-curable adhesive layer used in processing a thin semiconductor wafer.

Conventionally, a semiconductor integrated circuit has been fabricated by fixing a semiconductor wafer having a specific circuit pattern formed on a die pad with an adhesive. The semiconductor wafer used at this time can be manufactured, for example, by the following method.

(1) After a high-purity germanium single crystal is sliced to form a semiconductor wafer, a specific circuit pattern such as an IC is formed on the surface of the wafer.

(2) After bonding the surface protection tape for protecting the circuit surface of the semiconductor wafer, and protecting the formed circuit surface, the back surface of the wafer is polished by a grinder to thin the thickness of the wafer to about 100 to 600 μm, and thereafter Peel off the surface protection tape from the circuit surface.

(3) attaching the dicing sheet to an annular cutting frame having a hollow portion slightly larger than the diameter of the semiconductor wafer, and attaching the back surface of the wafer polished by the grinding machine to the adhesion of the hollow portion exposed to the frame Agent layer.

(4) A semiconductor wafer is formed by cutting from the opposite side of the surface on which the dicing sheet is bonded (that is, the side on which the circuit is formed), and radiation such as ultraviolet rays is irradiated to lower the adhesive force of the adhesive layer of the dicing sheet, and then the needle is removed. The wafer was lifted up from the substrate film side of the dicing sheet to be picked up.

Regarding the dicing sheet used in this step, it is necessary to have an adhesive force which does not peel off during the cutting process, and on the other hand, it is necessary to be able to carry out the semiconductor with a low adhesion force which can be easily peeled off after picking up. The wafer is peeled off from the dicing sheet, and a contaminant represented by an adhesive is not attached to the back surface of the wafer.

On the other hand, in recent years, a thin semiconductor wafer having a thickness of 100 μm or less has been obtained from a wafer having a diameter of 300 mm. Therefore, how to smoothly obtain a semiconductor wafer from the thin wafer has become an important issue.

One of the solutions to this problem is to disclose a so-called in-line manufacturing apparatus that performs the above steps (1) to (3) in a continuous apparatus, or a manufacturing method that rapidly performs the steps (2) and (3). For example, refer to Patent Documents 1, 2). For example, in the in-line manufacturing apparatus, the step of polishing the back surface of the wafer (2) and (3) the step of bonding the dicing sheet to the back side of the wafer are continuously performed. Therefore, damage to the semiconductor wafer or the semiconductor wafer can be reduced in the in-line manufacturing apparatus. In this apparatus, a dicing sheet is bonded before the oxide film on the back side of the wafer is formed.

However, since the dicing sheet having the previous adhesive layer is bonded to the back surface of the wafer to form an oxidized film, the following problem arises: even if it can be smoothly peeled off in this case, it is also impossible to use it for the in-line manufacturing apparatus. Smoothly stripped.

Further, in the prior manufacturing step, since the dicing sheet is bonded after the oxide film is formed on the back surface of the wafer, the following problem arises: even in the case where the dicing sheet having the previous adhesive layer which can be smoothly peeled off in this case is used in the same manner It is also impossible to peel off smoothly in the in-line manufacturing apparatus.

Further, in one of the other solutions, a so-called dicing die bond sheet in which an adhesive agent formed into a film shape is laminated on an adhesive layer of a dicing tape in advance is proposed. Used when the wafer is attached to the wafer holder. When the dicing die is used, it is bonded to the back surface of the wafer in the same manner as a general dicing sheet, but the adhesive layer is also cut together with the adhesive layer. Since the sheet is bonded to the adhesive layer, the strength of the entire tape is increased, and the sheet itself has the effect of enhancing the strength of the thin wafer. Therefore, the thin wafer can be cut smoothly. However, after the end of the dicing, the adhesive layer remains on the back surface of the semiconductor wafer, and the adhesive layer and the adhesive layer must be peeled off. Therefore, a sheet using a specific radiation curing type as an adhesive layer is used. Recently, the amount of radiation irradiation after the cutting step is being increased to accelerate the manufacturing steps of the semiconductor wafer. However, when the amount of radiation irradiation increases, the amount of heat generation increases, which causes a problem that it is difficult to peel off the adhesive layer and the adhesive layer due to heat generated in the radiation irradiation step after the dicing step.

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2002-343756

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2004-40114

An object of the present invention is to provide an adhesive sheet for processing a semiconductor wafer which can be easily peeled off after the cutting step is completed and which can reduce the adhesion of contaminants when the dicing sheet is closely attached to the back surface of the wafer.

Further, an object of the present invention is to provide an adhesive sheet for semiconductor wafer processing which is capable of easily forming an adhesive layer in a pick-up step by further providing an adhesive sheet for a semiconductor wafer processing having an adhesive layer on an adhesive layer. The adhesive layer is peeled off to obtain a semiconductor wafer with an adhesive layer attached thereto.

The present inventors have conducted intensive studies on the above-mentioned problems, and as a result, have found that the above problems can be solved by using any of the following adhesive sheets for semiconductor wafer processing:

(I) Using a radiation curable resin composition containing a base resin having a specific radiation curable acrylic polymer as a main component and a photopolymerization initiator having a specific molecular weight, an adhesive layer is formed on the base resin film Adhesive sheet for semiconductor wafer processing; or

(II) An adhesive sheet for semiconductor wafer processing in which a radiation polymerizable adhesive layer containing a radiation polymerizable compound and a resin composition of a photopolymerization initiator having a specific molecular weight in an acrylic polymer is formed. The present invention has been completed based on this finding.

That is, the present invention provides the following adhesive sheets for semiconductor wafer processing:

<1> An adhesive sheet for processing a semiconductor wafer, which is formed of a radiation-permeable base resin film and an adhesive layer on the base resin film, the adhesive layer being used in comparison with (i-1) 100 parts by mass of a base resin comprising (iii) a photopolymerization initiator (b) in an amount of 0.1 to 10 parts by mass of a radiation curable resin composition, the (i-1) base resin being used for the main chain The repeating unit is bonded to the acrylic polymer (a) having a residue of a (meth)acrylic monomer portion as a main component, and the (meth)acrylic monomer portion has a radiation curable carbon-carbon double bond. a base, the (iii) photopolymerization initiator (b), which has a weight average molecular weight of less than 1000 in terms of polystyrene as a standard substance by gel permeation chromatography (hereinafter referred to as "GPC");

<2> An adhesive sheet for processing a semiconductor wafer, which is formed of a radiation-permeable base resin film and an adhesive layer on the base resin film, the adhesive layer being used in comparison with (i-2) 100 parts by mass of the acrylic polymer containing (ii) 1 to 300 parts by mass of the compound (c), and (iii) 0.1 to 10 parts by mass of the photopolymerization initiator (b), a layer of a radiation curable resin composition (ii) the compound (c) having a weight average molecular weight of at least 2 photopolymerizable carbon-carbon double bonds in the molecule of 10,000 or less, (iii) a photopolymerization initiator (b) by coagulation Gel permeation chromatography (hereinafter referred to as "GPC") method, the weight average molecular weight of polystyrene as a standard substance is less than 1000;

<3> The adhesive sheet for semiconductor wafer processing according to <1> or <2>, wherein the photopolymerization initiator (b) is selected from the group consisting of 1-hydroxy-cyclohexylphenyl-ketone, 2,2-di Methoxy-1,2-diphenylethane-1-one, 2-methyl-1-(4-methylthiophenyl)-2- Olinyl propan-1-one, and oligomer represented by the following formula (1)

At least one of the group consisting of (wherein R represents an alkyl group and n is an integer);

<4> The adhesive sheet for semiconductor wafer processing according to <3>, wherein the degree of polymerization of the oligomer represented by the above formula (1) is n=2 to 4;

<5> The adhesive sheet for semiconductor wafer processing of <1>, <3> or <4>, wherein the repeating unit with respect to the main chain contains an acrylic single sheet having a radiation-polymerizable carbon-carbon double bond-containing group The polymer (a) having a body as a constituent unit has an iodine value of 1 to 50;

<6> An adhesive sheet for processing a semiconductor wafer, further comprising an adhesive layer on the adhesive layer of the adhesive sheet for semiconductor wafer processing according to any one of <1> to <5>.

According to the adhesive sheet for semiconductor wafer processing of the present invention, when the dicing sheet is brought into close contact with the wafer back surface, the dicing sheet can be easily peeled off after the dicing step, and the adhesion of the contaminant can be remarkably reduced.

Further, by further providing an adhesive sheet for processing a semiconductor wafer with an adhesive layer on the adhesive layer of the present invention, the adhesive layer and the adhesive layer can be easily peeled off in the pick-up step to obtain an adhesive layer. Semiconductor wafer.

The above and other features and advantages of the present invention will be made apparent by reference to the accompanying drawings.

Hereinafter, a preferred adhesive sheet for semiconductor wafer processing of the present invention will be described with reference to the drawings.

1 is a schematic cross-sectional view showing a preferred embodiment of the adhesive sheet for semiconductor wafer processing of the present invention, in which a base resin film 1 is formed, and an adhesive layer 2 is formed on the base resin film 1. Moreover, Fig. 2 is a schematic cross-sectional view showing a preferred embodiment of the adhesive sheet for semiconductor wafer processing of the present invention. In FIG. 2, the base resin film 1 is formed, and the adhesive layer 2 is formed on the base resin film 1, and the adhesive layer 3 is formed further.

The adhesive layer in the present invention is composed of a radiation curable resin composition containing a specific blending amount of a radiation-polymerizable compound in a base resin, and blended in a specific manner. Amounts containing a specific photopolymerization initiator. By using the adhesive sheet for semiconductor wafer processing of the present invention, after the end of the dicing process, the radiation is irradiated from the side of the base material resin film of the following radiation-transmissive property, and the adhesive force of the adhesive layer is lowered. Thereby, the semiconductor wafer can be picked up smoothly. In the same manner as the adhesive sheet for semiconductor wafer processing in which the adhesive layer is formed on the adhesive layer as shown in FIG. 2, the radiation is irradiated from the side of the base material resin film to be irradiated, and the adhesive layer is lowered. Adhesion. In this case, the semiconductor wafer with the adhesive layer can be obtained by peeling off at the interface between the adhesive layer and the adhesive layer, and can be directly fixed to the wafer holder.

The adhesive sheet for semiconductor wafer processing of the present invention shown in FIG. 1 can be smoothly peeled off in the pickup step after radiation irradiation even after the back surface of the semiconductor wafer is polished and adhered to the back surface. The surface of the semiconductor wafer immediately after the polishing is not completely formed with a natural oxide film, and becomes an active surface of the active atom in an unoxidized state. That is, in this case, the adhesive sheet for semiconductor wafer processing of the present invention can be smoothly peeled off after radiation irradiation, and the adhesion of contaminants caused by the adhesive component can be remarkably reduced.

Further, the adhesive sheet for semiconductor wafer processing of the present invention in which the adhesive layer is further provided with an adhesive layer as shown in FIG. 2 does not cause heat generated by irradiation of radiation after the end of the dicing step, but is adhered to the adhesive. A problem arises in the peeling of the layer from the adhesive layer.

In the sheet for semiconductor wafer processing of the present invention, the adhesive layer is formed on the base resin film to form a layer using a radiation curable resin composition. The sheet for semiconductor wafer processing of the present invention includes a first aspect and a second aspect. In each of the aspects, the sheet for semiconductor wafer processing including the aspect shown in FIG. 1 and the aspect shown in FIG. 2 is included. The base resin of the adhesive layer of the sheet for semiconductor wafer processing of the first aspect is (i-1), which is bonded to the repeating unit of the main chain and contains a radioluble carbon-carbon double bond. The acrylic polymer (a) having a residue of the (meth)acrylic monomer portion is used as a main component.

(Base resin of the adhesive layer of the sheet for semiconductor wafer processing of the first aspect)

The base resin of the radiation curable resin composition used in the adhesive layer of the sheet for semiconductor wafer processing of the first aspect is bonded with a radiation curable carbon-carbon double in a repeating unit for the main chain. The acrylic polymer (a) having a residue of a (meth)acrylic monomer portion of the group as a main component. In the present invention, the term "polymer" (a) as a main component means that the content of the base resin is from 50 to 100% by mass. Further, in the present invention, the (meth)acrylic single system means both of an acrylic monomer and a methacrylic monomer.

The above polymer (a) can be produced by any means. For example, the polymer (a) can be obtained by reacting the following acrylic copolymer and/or methacrylic copolymer (a1) with the compound (a2), and the acrylic copolymer and/or methacrylic acid. The copolymer (a1) is a compound having a radiation curable carbon-carbon double bond and having a functional group for a repeating unit of the main chain, and a compound (a2) having a functional group reactive with the functional group. Further, the acrylic copolymer and/or the methacrylic copolymer having a functional group may be (a1'), have a radiation-curable carbon-carbon double bond, and have a reactive group capable of reacting with (a1'). The compound of the functional group is (a2'), and these are reacted to form a polymer (a).

The acrylic copolymer and/or the methacrylic copolymer (a1) having a radiation-curable carbon-carbon double bond in the repeating unit of the main chain, and the functional group may, for example, be as follows (a1-1) and A1-2) obtained by copolymerization, (a1-1) is a monomer (a1-1) such as an alkyl acrylate having an electron-curable carbon-carbon double bond and/or an alkyl methacrylate, (a1) -2) is a monomer (a1-2) having a functional group.

The monomer (a1-1) may, for example, be an alkyl (meth)acrylate having an alkyl carbon number of 6 to 12 (for example, hexyl acrylate, n-octyl acrylate, isooctyl acrylate, acrylic acid). 2-ethylhexyl ester, dodecyl acrylate, decyl acrylate). Further, examples thereof include an alkyl (meth)acrylate having an alkyl carbon number of 5 or less (for example, amyl acrylate, n-butyl acrylate, isobutyl acrylate, ethyl acrylate, methyl acrylate, or The same methacrylate, etc.).

In the monomer (a1-1), the alkyl (meth)acrylate having a larger alkyl carbon number using an alkyl ester tends to have a lower glass transition point. Therefore, by appropriately selecting the alkyl carbon number of the alkyl ester of the monomer (a1-1), the polymer (a) having a desired glass transition point can be obtained.

Further, in addition to the glass transition point, in order to improve the compatibility with various other components or various properties, a low molecular compound having a carbon-carbon double bond such as vinyl acetate, styrene or acrylonitrile may be added to (a1-1). The polymer (a) was obtained. The blending amount of the low molecular weight compound is preferably 5% by mass or less based on the monomer (a1-1).

The functional group of the monomer (a1-2) may, for example, be a carboxyl group, a hydroxyl group, an amine group, a cyclic acid anhydride group, an epoxy group or an isocyanate group. Specific examples of the monomer (a1-2) include acrylic acid, methacrylic acid, cinnamic acid, itaconic acid, fumaric acid, phthalic acid, 2-hydroxyalkyl acrylate, and methyl group. 2-hydroxyalkyl acrylates, diol monoacrylates, diol monomethacrylates, N-methylol acrylamide, N-methylol methacrylamide, allyl alcohol, acrylic acid N-alkylaminoethyl esters, N-alkylaminoethyl methacrylates, acrylamides, methacrylamides, maleic anhydride, itaconic anhydride, fumaric anhydride , phthalic anhydride, glycidyl acrylate, glycidyl methacrylate, allyl epoxypropyl ether, and a part of the isocyanate group of the polyisocyanate compound hardened by having a hydroxyl group or a carboxyl group and radiation A monomer in which a carbon-carbon double bond is subjected to amine esterification.

In the case where the functional group of the above (a2) is a carboxyl group or a cyclic acid anhydride group, the functional group of (a1) may, for example, be a hydroxyl group, an epoxy group or an isocyanate group. In the case where the functional group of (a2) is a hydroxyl group, the functional group of (a1) may, for example, be a cyclic acid anhydride group or an isocyanate group. When the functional group of (a2) is an amine group, the functional group of (a1) may, for example, be an epoxy group or an isocyanate group. When the functional group of (a2) is an epoxy group, the functional group of (a1) may, for example, be a carboxyl group, a cyclic acid anhydride group or an amine group.

Specific examples thereof are the same as those enumerated in the specific examples of the monomer (a1-2).

In the reaction of (a1) and (a2), an acid value, a hydroxyl value or the like can be appropriately set within a range as described below by leaving an unreacted functional group.

The polymer (a) having an acrylic monomer having a radiation-polymerizable carbon-carbon double bond-containing group as a constituent unit in the repeating unit of the main chain can be obtained by solution polymerization in various solvents. A ketone system, an ester system, an alcohol system, or an aromatic group can be used as the organic solvent at the time of solution polymerization. It is generally preferred to use a solvent which is a preferred solvent for the acrylic polymer and has a boiling point of from 60 to 120 °C. For example, toluene, ethyl acetate, isopropanol, benzene, methacrylate, cesulfuron, acetone, methyl ethyl ketone, or the like can be used. As the polymerization initiator, a radical generator such as an azobis system such as α,α'-azobisisobutyronitrile or an organic peroxide such as benzamidine peroxide can be used. At this time, if necessary, a catalyst or a polymerization inhibitor can be used in combination, and by adjusting the polymerization temperature and the polymerization time, the polymer (a) having a desired molecular weight can be obtained. Further, in order to adjust the molecular weight, it is preferred to use a mercaptan or a carbon tetrachloride solvent. Further, the synthesis of the polymer (a) is not limited to solution polymerization, and other methods such as bulk polymerization or suspension polymerization may be used.

In the present invention, the weight of the acrylic polymer (a) containing a residue having a (meth)acrylic monomer portion having a radiation-curable carbon-carbon double bond-containing monomer group is bonded to the repeating unit of the main chain. The average molecular weight is preferably from about 300,000 to about 1,000,000. When the molecular weight is less than 300,000, the cohesive force caused by radiation irradiation is reduced, and when the wafer is diced, the component is likely to be shifted, and image recognition becomes difficult. In order to prevent the offset of the element as much as possible, the molecular weight is preferably 400,000 or more. Further, when the molecular weight exceeds 1,000,000, gelation may occur during the synthesis and at the time of coating. The weight average molecular weight of the polymer (a) in the present invention can be determined, for example, by the following method, as a weight average molecular weight in terms of polystyrene.

(Measurement conditions for weight average molecular weight)

GPC device: HLC-8120GPC (trade name, manufactured by Tosoh Corporation)

Pipe column: TSK gel Super HM-H/H4000/H3000/H2000 (trade name, manufactured by Tosoh Corporation)

Flow rate: 0.6ml/min

Concentration: 0.3% by mass

Injection volume: 20μl

Column temperature: 40 ° C

Developing solvent: chloroform

In the present invention, the iodine value of the polymer (a) having a radiation-polymerizable carbon-carbon double bond-containing group as a constituent unit with respect to the repeating unit of the main chain is preferably from 1 to 55. Further, it is preferably 2 to 30. If the iodine value is less than 1, the degree of crosslinking after radiation irradiation is small, and the peeling force is not completely lowered, so that the wafer cannot be sufficiently picked up. When the iodine value exceeds 50, the degree of crosslinking after radiation irradiation is large, and hardening shrinkage occurs, and the pick-up property of the wafer is lowered.

When the hydroxyl value of the polymer (a) is 5 to 100, the risk of picking failure can be further reduced by reducing the adhesion after radiation irradiation. It is dangerous and therefore better. Further, the acid value of the polymer (a) is preferably from 0.5 to 30.

Here, the hydroxyl value and the acid value refer to values measured by JIS K 0070. By setting the hydroxyl value of the polymer (a) within an appropriate range, the fluidity of the adhesive layer after the radiation irradiation can be made to be in an appropriate range, so that the adhesion after the radiation irradiation can be sufficiently reduced. By setting the acid value of the polymer (a) within an appropriate range, the fluidity of the adhesive layer after the radiation irradiation can be made to an appropriate range, thereby satisfying the tape recovery property.

The base resin used in the radiation curable resin composition constituting the adhesive layer of the present invention may be blended with the prior material within the scope not departing from the gist of the present invention. For example, a rubber-based polymer such as natural rubber or various synthetic rubbers; or a polyalkyl (meth) acrylate, an alkyl (meth) acrylate, and an alkyl (meth) acrylate may be used, and other copolymers thereof may be used. An acrylic copolymer such as a copolymer of an unsaturated monomer.

(Base resin of the adhesive layer of the sheet for semiconductor wafer processing of the second aspect)

The base resin of the radiation curable resin composition used in the adhesive layer of the sheet for semiconductor wafer processing of the second aspect is an acrylic polymer.

Examples of the acrylic polymer include a (meth) acrylate component as a monomer main component (% by mass in the polymer), and copolymerization of the (meth) acrylate component and the copolymerizable monomer component. Founder.

In the acrylic polymer, examples of the (meth) acrylate component of the monomer main component include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (methyl). Isopropyl acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, second butyl (meth)acrylate, tert-butyl (meth)acrylate, amyl (meth)acrylate , (meth) hexyl acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (methyl) Ethyl acrylate, isodecyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, Tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, cetyl (meth)acrylate, heptadecylate (meth)acrylate, (alkyl)alkyl (meth)acrylate such as octadecyl (meth)acrylate; cycloalkyl (meth)acrylate such as cyclohexyl (meth)acrylate; phenyl (meth)acrylate; Aryl acrylate and the like. The (meth) acrylate may be used singly or in combination of two or more.

(hardener)

The radiation curable resin composition constituting the adhesive layer of the adhesive sheet for semiconductor wafer processing of the first aspect and the second aspect may contain a polyisocyanate compound, an alkyl etherified melamine compound, or an epoxy compound. A hardener used in the past, such as a decane coupling agent. The initial adhesion can be set to an arbitrary value by making a resin composition blended with a hardener. Among the hardeners, an isocyanate-based hardener is preferably used.

As the isocyanate-based curing agent, specifically, a polyvalent isocyanate compound such as 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,3-methylxylene diisocyanate, 1,4-dimethylbenzene diisocyanate, or the like, may be used. Diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, Dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, isocyanuric acid isocyanate, and the like.

(a compound having a weight average molecular weight of at least 2 photopolymerizable carbon-carbon double bonds in the molecule of 10,000 or less)

The radiation curable resin composition used in the adhesive layer of the semiconductor wafer processing sheet of the second aspect contains a compound having at least two photopolymerizable carbon-carbon double bonds in the molecule and having a weight average molecular weight of 10,000 or less. (c). The compound (c) can be used without any particular limitation as long as it is three-dimensionally reticulated by curing by irradiation with radiation. The compound includes an oligomer having a weight average molecular weight of 10,000 or less, and does not include a high molecular weight polymer having a weight average molecular weight of more than 10,000. In order to efficiently perform three-dimensional network formation of the adhesive layer by irradiation of radiation, it is preferable that the number of carbon-carbon double bonds having a molecular weight of 5,000 or less and radiation polymerization in the molecule is 2 to 6.

Further, the weight average molecular weight of the low molecular weight compound having at least two photopolymerizable carbon-carbon double bonds in the molecule in the present invention is determined by GPC (gel permeation chromatography) under the following conditions. The weight average molecular weight in terms of polystyrene.

(Measurement conditions for weight average molecular weight)

GPC device: HLC-8120 GPC (trade name, manufactured by Tosoh Corporation)

Column: TSK-GEL G2500 HHR (trade name, manufactured by Tosoh Corporation)

Flow rate: 1ml/min

Concentration: 0.2mg/ml

Injection volume: 100μl

Bath temperature: 40 ° C

Mobile phase: chloroform

Examples of the radiation polymerizable compound (c) include trimethylolpropane triacrylate, tetramethylol methane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol. Alcohol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, organopolyoxyl A composition, a commercially available oligoester acrylate, an amide acrylate, or the like.

The compound having a weight average molecular weight of at least two photopolymerizable carbon-carbon double bonds in the molecule of 10,000 or less may be used singly or in combination of two or more. The blending amount is from 1 to 300 parts by mass based on 100 parts by mass of the base resin. It is preferably 30 to 200 parts by mass, and more preferably 50 to 150 parts by mass, per 100 parts by mass of the base resin. When the amount is too small, the three-dimensional network due to irradiation of the adhesive layer is insufficient, and it is difficult to peel the semiconductor wafer processing adhesive sheet from the wafer and contaminate the wafer. When the amount is too large, polymerization by radiation is excessively performed, and hardening shrinkage due to irradiation of radiation occurs. As a result, the adhesive layer is trapped in the surface of the adherend, and it becomes difficult to pick up when the diced semiconductor wafer is picked up. In addition, when the amount of the radiation polymerizable compound is too large, there is a problem that it is difficult to maintain the shape of the pressure-sensitive adhesive layer, and the thickness accuracy is deteriorated.

(photopolymerization initiator)

In the radiation curable resin composition constituting the adhesive layer of the adhesive sheet for semiconductor wafer processing of the first aspect and the second aspect, a gel permeation chromatography (hereinafter referred to as "GPC") method is used. A photopolymerization initiator having a weight average molecular weight of less than 1,000 in terms of polystyrene as a standard substance. In the present invention, the weight average molecular weight of the photopolymerization initiator refers to a value measured by GPC under the following conditions.

(Measurement conditions for weight average molecular weight)

GPC device: LCVP series manufactured by Shimadzu Corporation

Column: OligoPore 300×7.5 (trade name) (trade name, manufactured by Polymer Laboratories)

Flow rate: 1ml/min

Concentration: 1mg/ml

Injection volume: 50μl

Column temperature: 40 ° C

Developing solvent: chloroform

The photopolymerization initiator generates radicals by irradiating radiation such as light or ultraviolet rays. Thereby, it is possible to promote the hardening reaction of the polymer (a) containing the acrylic polymer having a radiation-polymerizable carbon-carbon double bond-containing group as a constituent unit in the repeating unit of the adhesive layer contained in the adhesive layer, or to promote A hardening reaction of a compound having a weight average molecular weight of at least two photopolymerizable carbon-carbon double bonds in the adhesive layer of 10,000 or less contained in the adhesive layer. When the weight average molecular weight obtained by GPC in terms of polystyrene in the polystyrene conversion agent is too large, the dispersion of the photopolymerization initiator in the adhesive layer causes a problem, and the movement of the generated radicals is difficult to proceed rapidly. Therefore, the hardening reaction cannot be performed efficiently. In this case, it is necessary to irradiate radiation exceeding a required high illuminance, and it is difficult to effectively reduce the adhesion between the adhesive layer and the adherend due to heat generation.

In the case of the semiconductor wafer processing adhesive sheet 10 in which the adhesive layer 2 is formed on the base resin film 1, as shown in FIG. There are obstacles in picking up. Further, as shown in FIG. 2, when the adhesive layer 2 is provided on the base resin film 1, and the adhesive sheet 20 for semiconductor wafer processing of the adhesive layer 3 is formed, it is difficult to smoothly apply the adhesive layer 3. Stripped with the adhesive layer 2.

The upper limit of the weight average molecular weight by GPC in terms of polystyrene in the photopolymerization initiator is preferably 800, and more preferably 600.

The lower limit of the weight average molecular weight obtained by GPC in terms of polystyrene in terms of the photopolymerization initiator is not particularly limited, but is preferably 200 or more. If the molecular weight is small, it becomes easy to sublimate, and the movement from the adhesive layer to the non-adhesive layer becomes remarkable and the wafer is easily contaminated. Moreover, the heat resistance of the adhesive layer is deteriorated, and it is easily decomposed in the drying step after the application of the substrate at the time of production. Therefore, a stable hardening reaction was not exhibited.

Examples of the photopolymerization initiator include benzophenone, 4,4-bis(diethylamino)benzophenone, 2,4,6-trimethylbenzophenone, and 4-phenyl group. Benzophenone, tert-butyl hydrazine, 2-ethyl hydrazine, diethoxy acetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2- Dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexyl-phenyl ketone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2-methyl -1-[4-(methylthio)phenyl]-2- Lolinylpropan-1-one, 2-benzyl-2-dimethylamino-1-(4- Polinylphenyl)-butanone-1, diethyl-9-oxosulfur Isopropyl-9-oxosulfur , 2,4,6-trimethylbenzimidyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzylidene)phenylphosphine oxide, 2-hydroxy-1-{4 -[4-(2-hydroxy-2-methylpropenyl)benzyl]phenyl}-2-methylpropan-1-one, 2-(dimethylamino)-2-[(4- Methylphenyl)methyl]-1-[4-(4- An orally represented by the following formula (1): phenyl)phenyl]-1-butanone.

(wherein R represents an alkyl group and n is an integer)

Among the above photopolymerization initiators, an excellent photopolymerization initiator which is difficult to sublimate and which is less likely to cause contamination, is exemplified by 2,2-dimethoxy-1,2-diphenylethane-1- Ketone (molecular weight 260), 2-methyl-1-(4-methylthiophenyl)-2- Lolinylpropan-1-one (molecular weight 280), 1-hydroxy-cyclohexylphenyl-one (molecular weight 205).

The oligomer of the above formula (1) preferably has a degree of polymerization of n = 2 to 4 (molecular weight: 400 to 700), and more preferably has a degree of polymerization of n = 2 to 3 (molecular weight: 400 to 500).

2,2-dimethoxy-1,2-diphenylethane-1-one

2-methyl-1-(4-methylthiophenyl)-2- Lolinylpropan-1-one

The photopolymerization initiator is blended in an amount of 0.1 to 10 parts by mass based on 100 parts by mass of the base resin in the radiation curable resin composition of the pressure-sensitive adhesive layer for the semiconductor wafer processing adhesive sheet of the first aspect. It is preferably 1 to 10 parts by mass, more preferably 2 to 7 parts by mass, based on 100 parts by mass of the base resin. The radiation-curable resin composition of the adhesive layer of the adhesive sheet for semiconductor wafer processing of the second aspect is blended in an amount of 0.1 to 10 parts by mass based on 100 parts by mass of the acrylic polymer. It is preferably 1 to 10 parts by mass, more preferably 2 to 7 parts by mass, based on 100 parts by mass of the acrylic polymer.

When the amount of the photopolymerization initiator is too small, the three-dimensional network due to irradiation of the adhesive layer is insufficient, and the electrode layer cannot be smoothly peeled off or the semiconductor wafer is contaminated. Further, if the amount of the photopolymerization initiator is too large, not only the effect corresponding thereto but also the photopolymerization initiator remains on the wafer.

Two or more kinds of the above photopolymerization initiators may be used in combination as needed. The weight average molecular weight obtained by using GPC for each of the photopolymerization initiators used may be less than 1,000. Further, an amine compound such as triethylamine, tetraethylenepentamine or dimethylaminoethanol or 9-oxosulfuric acid may also be used. A photopolymerization initiator is used in combination as a photopolymerization accelerator.

The radiation curable resin composition may optionally contain an adhesion-imparting agent, an adhesion regulator, a surfactant, another modifier, or a conventional component in order to adjust the adhesion to the semiconductor wafer. Among them, a surfactant or a compound exhibiting interface activity may contaminate a semiconductor wafer, and therefore it is preferable to minimize the use thereof.

In the present invention, the base resin, a compound having a weight average molecular weight of at least 2 photopolymerizable carbon-carbon double bonds in the molecule of 10,000 or less, a specific photopolymerization initiator, and optionally a crosslinking agent The radiation-polymerizable resin composition of the other blending agent component is directly applied onto the base resin film and dried by heating, or is temporarily applied onto the release paper, dried, and then transferred onto the base resin film to be manufactured. The adhesive layer is an adhesive sheet for semiconductor wafer processing which is composed of a layer of a radiation polymerizable resin composition.

The thickness of the adhesive layer is not particularly limited. Usually, the adhesive layer is formed so that the thickness of the adhesive layer is usually 5 to 100 μm, and the adhesive sheet for semiconductor wafer processing such as a sheet or a strip is formed.

As the radiation, α rays, γ rays, electron beams, ultraviolet rays, or the like can be used, and there is no particular limitation as long as the adhesion is lowered by curing the adhesive layer. It is preferably an electron beam or an ultraviolet ray, and when a photopolymerization initiator is used, it is preferably ultraviolet ray.

As shown in FIG. 2, the adhesive sheet for semiconductor wafer processing of the present invention may be provided with an adhesive layer 2 on the base resin film 1, and an adhesive layer 3 may be formed thereon. The method of forming the adhesive layer on the base resin film and then forming the adhesive layer is not particularly limited as long as the adhesive layer is laminated on the base resin film according to the prior method, and the adhesive layer is laminated on the adhesive layer. Just fine.

In this case, the semiconductor wafer processing adhesive sheet is bonded to the back surface of the polished semiconductor wafer, and thereafter, from the circuit formation surface side of the semiconductor wafer, the adhesive and the adhesive are cut while being cut. A semiconductor wafer with an adhesive layer can then be obtained. As the adhesive used in the layer 3, a conventional adhesive can be used.

The subsequent layer can be formed by pre-filming an adhesive. For example, a conventional polyimide resin, a polyamide resin, a polyether oxime resin, a polyamide amide resin, a polyester resin, a polyester phthalimide resin, a phenoxy resin used for an adhesive can be used. , polyfluorene resin, polyether oxime resin, polyphenylene sulfide resin, polyether ketone resin, chlorinated polypropylene resin, acrylic resin, polyurethane resin, epoxy resin, polypropylene amide resin, melamine resin, etc. or the like mixture.

Among them, in terms of excellent heat resistance after hardening, it is particularly preferable to use an epoxy resin. The epoxy resin may be used as it is for curing. A polyfunctional epoxy resin may also be added in order to increase the glass transition temperature (Tg) to ensure the heat resistance of the adhesive layer. The polyfunctional epoxy resin may, for example, be a phenol novolac type epoxy resin or a cresol novolak type epoxy resin. The curing agent for the epoxy resin is not particularly limited as long as it is generally used as a curing agent, and examples thereof include an amine compound, polyamine, an acid anhydride, a polysulfide, and boron trifluoride, and two or more phenols per molecule. The compounds of the hydroxy group are bisphenol A, bisphenol F, and bisphenol S.

Since it is particularly excellent in electric corrosion resistance at the time of moisture absorption, it is preferable to use a phenol novolak resin or a bisphenol novolak resin as a phenol resin. Further, in order to shorten the time for heat treatment for hardening, it is preferred to use a hardening accelerator together with the hardener. For the hardening accelerator, 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium, trimellitic acid can be used. A base such as an imidazole such as 1-cyanoethyl-2-phenyl imidazolium trimellitate.

Further, in order to enhance the adhesion to the semiconductor wafer or the lead frame, it is preferred to add a decane coupling agent or a titanium coupling agent as an additive to the above resin or a mixture thereof. Further, a filler may be added to improve heat resistance or adjust fluidity. As such a filler, for example, cerium oxide, aluminum oxide, an oxide of cerium, or the like can be used. These fillers may be blended at any ratio as long as the maximum particle diameter is smaller than the thickness of the adhesive layer.

The thickness of the subsequent agent layer is not particularly limited, but is usually preferably about 5 to 100 μm. Further, the adhesive layer can be laminated on the entire adhesive layer of the adhesive film. Further, an adhesive which is precut in a shape corresponding to the bonded semiconductor wafer may be laminated on one portion of the adhesive layer. In this case, a shape is formed in which an adhesive layer is present in a portion where a semiconductor wafer is bonded, and an adhesive layer in which a bonding film is not present in a portion in which a ring frame is bonded and only an adhesive film is present. Floor. By forming the shape, the adhesive layer is bonded to the ring frame, and the adhesive layer which is usually difficult to peel off from the adherend is not bonded. Therefore, the adhesive sheet for semiconductor wafer processing of the present invention can be easily used after use. The ground is peeled off from the ring frame.

In the adhesive sheet for semiconductor wafer processing of the present invention, in order to cure the adhesive layer by irradiating radiation from the side of the base resin film at the time of peeling, it is necessary to impart radiation permeability to the base resin film. Further, during wafer processing, the blade is subjected to an impact due to a cutting blade or the like, and is subjected to pressure such as washing water. Therefore, the base resin film is selected to have a material that can withstand such strength and is suitable for the materials and thicknesses. In order to make it difficult for the adhesive layer to be peeled off from the base resin film, it is preferred to perform various surface treatments represented by corona treatment on the adhesive layer forming surface of the base resin film in advance.

Examples of the material used for the base resin film include polyethylene, polypropylene, ethylene-propylene copolymer, polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, and ethylene-vinyl acetate. Ester copolymer, polybutene-1, poly-4-methylpentene-1, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-acrylic acid copolymer, polyurethane, polymethylpentene , a film of polybutadiene or the like.

The thickness of the base resin film is 30 to 500 μm, preferably 40 to 300 μm, and more preferably 50 to 200 μm. If the thickness is too small, the strength is weakened, which may cause defects due to breakage or the like in semiconductor wafer processing.

On the other hand, when the base resin film is too thick, the semiconductor wafer processing adhesive sheet is excessively hard in the pickup step of the semiconductor wafer after the dicing step is completed, and a failure occurs when the needle is lifted up. Further, in the expansion step after the cutting step and before the picking step, it is difficult to sufficiently extend the adhesive sheet for semiconductor wafer processing. Therefore, the gap between the semiconductor wafers is small, and the wafer discriminability of the image becomes insufficient, resulting in poor pickup of the semiconductor wafer.

[Examples]

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the examples.

A. Radiation hardening

1. Preparation of a radiation curable resin composition used in an adhesive layer of an adhesive tape for semiconductor wafer processing according to a first aspect

(1) Preparation of a polymer having a residue having a (meth)acrylic monomer portion having a radiation-curable carbon-carbon double bond-containing monomer group for a repeating unit of a main chain

An acrylic copolymer was produced using butyl acrylate (59 mol%), 2-hydroxyethyl acrylate (25 mol%), and acrylic acid (16 mol%). The OH group at the side of the 2-hydroxyethyl acrylate side chain of the acrylic copolymer is reacted with the NCO group of 2-methylpropenyloxyethyl isocyanate to obtain a repeating unit for the main chain, and the bond is contained. A polymer having a residue of a (meth)acrylic monomer portion having a radiation curable carbon-carbon double bond. At this time, the amount of addition of 2-isocyanatoethyl methacrylate is appropriately changed to obtain polymers ((a1) to (a4)) having different amounts of double bonds. Any of the obtained polymers ((a1) to (a4))) had a weight average molecular weight of 700,000 and a glass transition temperature of -60 °C. In Tables 1-1 to 1-4, the iodine of the polymer (a1) used in Examples 1-1 to 1-9, 1-11, and Comparative Examples 1-1 to 1-4, 1-7 The value is 20. Further, the polymer (a2) used in Example 1-10 had an iodine value of 50, and the polymer (a3) used in Example 1-12 had an iodine value of 0.5, which was used in Example 1-13. The polymer (a4) had an iodine value of 55.

In the following description, the polymer ((a1) to (a4))) will be described as the polymer (a).

(i) Weight average molecular weight

The weight average molecular weight of the polymer (a) was measured by GPC under the following conditions.

GPC device: HLC-8120GPC (trade name, manufactured by Tosoh Corporation)

Pipe column: TSK gel Super HM-H/H4000/H3000/H2000 (trade name, manufactured by Tosoh Corporation)

Flow rate: 0.6ml/min

Concentration: 0.3% by mass

Injection volume: 20μl

Column temperature: 40 ° C

Developing solvent: chloroform

(ii) Glass transition temperature

The measurement was carried out at a temperature elevation rate of 5 ° C/min using a thermal differential scanning analyzer (DSC) (DSC 7020 (trade name), manufactured by Seiko Instruments Co., Ltd.).

(iii) double bond amount

The iodine value was determined in accordance with JIS K 0070.

(2) Preparation of radiation curable resin composition

In 100 parts by mass of the polymer (a) obtained in the above (1), the photoinitiator is blended in parts as shown in Tables 1-1 to 1-4, and further blended with a polyisocyanate compound (manufactured by Nippon Polyurethane Co., Ltd.) In the case of the product of the present invention, the radioactive resin composition described in the examples and the comparative examples of Tables 1-1 to 1-4 was prepared as a curing agent in an amount of 3 parts by mass. VPE-0201 (trade name, manufactured by Wako Pure Chemical Industries, Ltd.) was used as a photopolymerization initiator used in Comparative Examples 1-1, 1-7, and a polyethylene glycol unit-containing polymer azo polymerization initiator- .

The weight average molecular weight of the photoinitiator was measured by a GPC method, and the weight average molecular weight was calculated using polystyrene as a standard material. The results are shown together in Tables 1-1 to 1-4. Oligo Pore 300 x 7.5 (trade name) manufactured by Polymer Laboratories was used as a gel permeation chromatography. The developed solvent was measured at 40 ° C using chloroform.

2. Preparation of a radiation curable resin composition for an adhesive tape for semiconductor wafer processing according to a second aspect

(1) Acrylic polymer constituting the adhesive layer

An acrylic copolymer was prepared as a base resin constituting the adhesive layer by using 85 parts by mass of n-butyl acrylate, 10 parts by mass of ethyl acrylate, and 5 parts by mass of acrylic acid. Its weight average molecular weight is 600,000.

(2) a compound having at least two photopolymerizable carbon-carbon double bonds in the molecule and having a weight average molecular weight of 10,000 or less

UN-3320HA (trade name, manufactured by Kokusai Industrial Co., Ltd.), UN-9000 PEP (trade name, manufactured by Kokusai Industrial Co., Ltd.), UN-6050PTM (trade name, manufactured by Kokusai Industrial Co., Ltd.), UN-901T (trade name, manufactured by Kokusai Industrial Co., Ltd.), UN -9200A (trade name, manufactured on root).

The weight average molecular weight and the amount of double bonds in terms of polystyrene of the compound used were measured by the following methods. The result is as follows.

UN-3320HA (trade name, manufactured on root): 1500 (double bond amount: 6)

UN-3320HC (trade name, manufactured on root): 1500 (double bond amount: 6)

UN-9000PEP (trade name, manufactured on root): 5000 (double bond amount: 2)

UN-6050PTM (trade name, manufactured on root): 6000 (double bond amount: 2)

UN-901T (trade name, manufactured on root): 4000 (double bond amount: 9)

UN-9200A (trade name, manufactured on root): 11500 (double bond amount: 2)

(Measurement conditions for weight average molecular weight)

GPC device: HLC-8120GPC (trade name, manufactured by Tosoh Corporation)

Column: TSK-GEL G2500HHR (trade name, manufactured by Tosoh Corporation)

Flow rate: 1ml/min

Concentration: 0.2mg/ml

Injection volume: 100μl

Bath temperature: 40 ° C

Mobile phase: chloroform

(Method for measuring double bond amount)

Double bond amount

The iodine value was determined in accordance with JIS K 0070, and the amount of double bonds was calculated from the value.

(3) Preparation of radiation curable resin composition

In 100 parts by mass of the base resin of (1), at least two photopolymerizable carbon-carbon doubles are contained in the molecule as described in (2) in the parts described in Tables 2-1 to 2-4. A compound having a weight average molecular weight of 10,000 or less and a photoinitiator, and further containing 3 parts by mass of a polyisocyanate compound (manufactured by Nippon Polyurethane Co., Ltd., trade name Coronate L) as a curing agent, thereby preparing Table 2-1 to Table 2 4. The radiation curable resin composition described in the examples and the comparative examples. VPE-0201 (trade name, manufactured by Wako Pure Chemical Industries, Ltd.) was used as a polyethylene hydride polymerization initiator containing a polyethylene glycol unit as a photoinitiator used in Comparative Examples 2-1 and 2-6. .

The weight average molecular weight of the photoinitiator was measured by a gel permeation chromatography (GPC) method, and polystyrene was used as a standard material to calculate a weight average molecular weight. The results are shown together in Tables 2-1 to 2-4. OligoPore 300 x 7.5 (trade name) manufactured by Polymer Laboratories was used as a gel permeation chromatograph. The solvent was developed using chloroform, and the measurement was carried out at 40 °C.

B. Production of Adhesive Sheets for Semiconductor Wafer Processing (I)

A base resin film having a thickness of 100 μm was produced by a T-die method using EMMA resin (manufactured by Sumitomo Chemical Co., Ltd., trade name: ACRYFT WD201). Examples 1-1 to 1-10, 1-12 to 1-13, 2-1 to 2-10, and Comparative Examples 1-1 to 1-4 and 2-1 to 2 were applied to the base resin film. The radiation curable resin composition shown in 5 is suitably cured. Thereby, an adhesive sheet for semiconductor wafer processing having the composition shown in FIG. 1 having a film thickness of 10 μm after drying was obtained.

3. Production of adhesive wafers for semiconductor wafer processing (II)

(1) Preparation of an adhesive composition constituting an adhesive layer

Γ-mercaptopropyltrimethoxydecane as a decane coupling agent, 3 parts by mass and γ-ureidopropyl group, based on 50 parts by mass of a cresol novolac type epoxy resin as an epoxy resin and 50 parts by weight of a phenol resin To the composition comprising 5 parts by mass of a triethoxy decane and 30 parts by weight of a spherical cerium oxide as a filler, cyclohexanone was added thereto, stirred and mixed, and further kneaded for 90 minutes using a bead mill.

300 parts by mass of an acrylic rubber (weight average molecular weight: 150,000) and 1 part by mass of 1-cyanoethyl-2-phenylimidazole as a curing accelerator were added to the above composition, and the mixture was stirred and mixed, and vacuum degassed. Thereby an adhesive composition is obtained.

(2) Production of adhesive sheets for semiconductor wafer processing

The adhesive composition obtained in (1) was applied onto a release-treated polyethylene terephthalate film (release film) having a thickness of 35 μm, and dried by heating at 140 ° C for 5 minutes to obtain a film thickness. An adhesive sheet in which an adhesive layer is formed on a release film of a B phase of 20 μm.

Then, the adhesive sheet for semiconductor wafer processing having the structure shown in FIG. 1 is obtained in the same manner as the method described in the above (2), the production of the adhesive sheet for semiconductor wafer processing, and the structure is: In the radiation polymerizable resin composition described in Examples 1 to 11 and Comparative Example 1 to 1-4, an adhesive layer was formed on the base resin film. The adhesive layer is laminated on the adhesive layer of the adhesive sheet produced by the above method, and the laminate shown in FIG. 2 is obtained: an adhesive sheet in which a release film is laminated on an adhesive sheet for semiconductor wafer processing (Example) 1-11 and Comparative Examples 1-7).

In addition, the adhesive sheet for semiconductor wafer processing having the structure shown in FIG. 1 is obtained in the same manner as the method described in the above (2) production of the adhesive sheet for semiconductor wafer processing, and the structure is: In the radiation polymerizable resin composition described in Examples 2-11 to 2-15 and Comparative Examples 2-6 and 2-7, an adhesive layer was formed on the base resin film. The adhesive layer is laminated on the adhesive layer of the adhesive sheet produced by the above method, and an adhesive sheet having a release film laminated on the adhesive sheet for semiconductor wafer processing shown in FIG. 2 is obtained (Example) 2-11 to 2-15, Comparative Examples 2-6, 2-7).

In the following test, the release film was peeled off and bonded to a semiconductor wafer, and evaluated.

4. Performance test

The cutting was performed under the following conditions, and thereafter the pick-up property and the wafer contamination were evaluated.

(cutting conditions)

(1) The adhesive sheet for semiconductor wafer processing constructed as shown in FIG.

Examples 1-1 to 1-10, 1-12, 1-13, 2-1 to 2-10, and Comparative Examples 1-1 to 1-4 and 2-1 to 2-5 were produced by DISCO Corporation. In the "DFD-840", the back surface of the tantalum wafer was polished by 30 μm on both axes, and then the final thickness of the tantalum wafer was 100 μm. The polishing conditions at this time are as follows.

Single axis: 350 grindstone (rotation speed: 4800 rpm, falling speed: P1 is 3.0 μm/sec, P2 is 2.0 μm/sec)

Double axis: #2000 grindstone (rotation speed: 5500 rpm, falling speed: P1 is 0.8 μm/sec, P2 is 0.6 μm/sec)

The adhesive sheet for semiconductor wafer processing of the structure of FIG. 1 was bonded to a ring frame of 8 inches in a state of 5 mm after the back surface polishing, and 8 μm thick was 100 μm in the state of being bonded and fixed. The wafer was bonded to an adhesive sheet for semiconductor wafer processing, and a cutting device DAD340 (trade name) manufactured by DISCO Corporation was used, and full cut dicing was performed to a wafer size of 5 mm × 5 mm. The cutting depth of the blade from the adhesive sheet surface for semiconductor wafer processing at this time is set to 30 μm in the case of the adhesive sheet formed as shown in FIG.

(2) The adhesive sheet for semiconductor wafer processing constructed as shown in Fig. 2

With respect to Examples 11-1, 2-11 to 2-15, and Comparative Examples 1-7, 2-6, and 2-7, the adhesive sheet for semiconductor wafer processing of the structure of FIG. 2 was bonded at 70 ° C. After 20 seconds of a 100-inch thick 8-inch wafer, the DFD 6340 manufactured by Disco was used, and the cutting was performed under the following conditions.

Cutting blade (thin rotary grindstone): The first use of 27HEEE manufactured by Disco, the second use of 27HEDD manufactured by Disco

Blade speed: 35000rpm

Blade feed speed: 50mm/s

Wafer size: 5mm × 5mm

Cutting depth:

The first time cut 50μm into the wafer

The second time, the adhesive sheet for semiconductor wafer processing was cut into 40 μm (the thickness of the base resin film was 100 μm, the thickness of the adhesive layer was 10 μm, and the thickness of the adhesive layer was 20 μm).

4-1. Pick up test

Examples 1-1 to 1-10, 1-12, 1-13, 2-1 to 2-10, Comparative Examples 1-1 to 1-4, 2-1 to 2-5, and Example 1 11, 2-11 to 2-15, Comparative Examples 1-7, 2-6, 2-7 for the adhesive sheet for semiconductor wafer processing, respectively, under the conditions shown in the above 4. (1) and (2) After the dicing, the ultraviolet ray irradiator using a high-pressure mercury lamp was used to irradiate the surface of the base resin film of the adhesive sheet for semiconductor wafer processing with an irradiation amount of 200 mJ/cm ² , and then CPS manufactured by CANON MACHINERY was used. -6820 (trade name), extended with an extension stroke of 5 mm, and picked up in this state. The picking is performed using an ejector pin having a top end diameter of R250. The evaluation project was implemented for the following projects.

(1) Picking

Actually picking up the wafer, evaluating a. smoothly ejecting the wafer, b. absorbing the wafer with a circular barrel clamp, and c. whether any of the wafers are placed on the lead frame can be smoothly performed. The evaluation was based on picking up 200 wafers from 8 inch wafers, of which number of wafers could be picked up. The case where 180 wafers or more were picked up in 200 wafers was regarded as pass, and the number of wafers successfully picked up was shown in Tables 1-1 to 2-4.

(2) wafer contamination

The wafer contamination is an adhesive sheet for semiconductor wafer processing configured as shown in Fig. 1 (Examples 1-1 to 1-10, 1-12, 1-13, 2-1 to 2-10, and Comparative Example 1-1). 1-4, 2-1 to 2-5) were evaluated by the following methods.

(2)-1 visual test

When the wafer contamination was evaluated, the wafer was peeled off and visually confirmed. The case where the iridescent luster caused by the adhesion of the adhesive or the adhesion of the contaminant is not present on the back side of the wafer, and the qualified condition is indicated as ○, which will produce a little gloss but the level of practical application is not a problem. In the case of Δ, the case where the adhesive was bonded was set as a failure, and it was represented by ×.

(2)-2 foreign body test

The surface-washed mirror-polished wafer (6 inches) was attached to the semiconductor wafer processing adhesive sheet, and after being left for 24 hours, the sheet was peeled off. The number of foreign matter remaining on the surface of the wafer to which the sheet was bonded was measured by a laser surface detecting device (Surfscan 6420 (trade name, manufactured by KLA-‧Tencor Co., Ltd.). The result was obtained based on the evaluation criteria shown below. The results were judged, wherein ◎ and ○ indicate pass, △ indicates a level that is not a problem in practical use, and × indicates a failure. The results are shown in the table.

◎: less than 20, ○: 20 or more and less than 90, △: 90 or more and less than 200, ×: 200 or more

(3) Peelability of adhesive layer and adhesive layer

The wafer having a diameter of 5 inches was placed on a heating plate heated to 80 ° C, and after confirming that the surface temperature of the silicon wafer reached 80 ° C, the semiconductor wafer processing of FIG. 2 was bonded in about 10 seconds. Adhesive sheets (Examples 1-11, 2-11 to 2-15, and Comparative Examples 1-7, 2-6, 2-7). Thereafter, the hot plate was removed, and the surface temperature of the tantalum wafer to which the semiconductor wafer processing adhesive sheet was bonded was lowered to room temperature.

Thereafter, ultraviolet irradiation was carried out so that the irradiation amount was 200 mJ/cm ^{2 from} the surface of the base resin film of the adhesive sheet for semiconductor wafer processing using an ultraviolet ray irradiator of a high-pressure mercury lamp. Thereafter, the peeling force of the adhesive sheet for semiconductor wafer processing after the ultraviolet irradiation on the wafer was measured in accordance with JIS-0237. The measurement conditions were peeled at 90°, and the peeling speed was 50 mm/min. The case where the peeling force was 0.5 N/25 mm or less was regarded as pass and was designated as ○.

5. The first aspect of the adhesive tape for semiconductor wafer processing

According to Tables 1-1 to 1-3, in the embodiment in which the adhesive sheet for semiconductor wafer processing shown in Fig. 1 was evaluated, it was possible to pick up more than 180 wafers of semiconductor wafers in 200 wafers, and wafer contamination Or foreign matter remains less and can be picked up smoothly. A few wafer contaminations or residual foreign matter were seen in Examples 1-6, but were not problematic in practical use.

Further, in the case of an adhesive sheet for semiconductor wafer processing which is composed of a polymer (a) having an iodine value of 0.5 as a base resin, 180 semiconductor wafers can be picked up in 200 wafers, which exhibits an acceptable level. Characteristics.

On the other hand, using a polymer azo polymerization initiator containing a polyethylene glycol unit as a photopolymerization initiator (Comparative Example 1-1), the photoinitiator was not sufficiently uniformly dissolved, and the generated radicals were generated. The movement cannot be performed smoothly enough, and as a result, only half of the 200 wafers can be picked up.

Further, when the amount of the photopolymerization initiator is less than 0.1 part by mass (Comparative Examples 1-2, 1-3), the radical supply due to the initiator is insufficient, and there is a problem in pick-up property. When the amount of the photopolymerization initiator was more than 10 parts by mass (Comparative Example 1-4), wafer contamination occurred due to sublimation due to unreacted materials.

Further, according to Tables 1 to 4, in Example 1-11 in which the adhesive sheet for semiconductor wafer processing shown in Fig. 2 was evaluated, the interface between the adhesive layer and the adhesive layer was smoothly performed. Stripping, all semiconductor wafers can be picked up in 200 wafers.

On the other hand, in Comparative Example 1-7, the interface peeling could not be smoothly performed between the adhesive layer and the adhesive layer, and only 100 semiconductor wafers could be picked up in 200 wafers.

5. The second aspect of the adhesive tape for semiconductor wafer processing

According to Tables 2-1 to 2-3, in the embodiment in which the adhesive sheet for semiconductor wafer processing shown in Fig. 1 was evaluated, all of the semiconductor wafers could be picked up in 200 wafers, and wafer contamination or foreign matter remained. Less and can be picked up smoothly. A small amount of wafer contamination or residual foreign matter can be seen in Examples 2-6, but is not a problem level in practical use.

On the other hand, using a polymer azo polymerization initiator containing a polyethylene glycol unit as a photopolymerization initiator (Comparative Example 2-1), the photoinitiator was not sufficiently uniformly dissolved, and the generated radicals were generated. The movement cannot be performed smoothly enough, and as a result, only half of the 200 wafers can be picked up.

Further, when the amount of the photopolymerization initiator is less than 0.1 part by mass (Comparative Example 2-2), the radical supply due to the initiator is insufficient, and there is a problem in pick-up property in photopolymerization. When the amount of the initiator was more than 10 parts by mass (Comparative Example 2-3), wafer contamination occurred due to sublimation due to unreacted materials.

When the blending amount of the compound having at least two photopolymerizable carbon-carbon double bonds in the molecule is less than 1 part by mass (Comparative Example 2-4), the pick-up property is lowered. On the other hand, when the blending amount of the radiation polymerizable compound is more than 300 parts by mass (Comparative Example 2-5), since the adhesive layer is hardened and shrinks, the adhesive is adhered to the back surface of the wafer, so that the pickup property is deteriorated. .

Further, according to Table 2-4, in Examples 2-11 to 2-15 in which the adhesive sheet for semiconductor wafer processing shown in Fig. 2 was evaluated, it was possible to form between the adhesive layer and the adhesive layer. Smooth interface stripping is possible, and all semiconductor wafers can be picked up in 200 wafers.

On the other hand, in Comparative Example 2-6 using a photopolymerization initiator having a large weight average molecular weight, interface peeling could not be smoothly performed between the adhesive layer and the adhesive layer, and only 100 of the 200 wafers could be picked up. Semiconductor wafers.

Further, in Comparative Example 2-7 in which the weight average molecular weight of the compound having at least two photopolymerizable carbon-carbon double bonds in the molecule was 11,500, similarly to Comparative Example 2-6, only 200 wafers were available. Pick up 100 semiconductor wafers.

The present invention and its embodiments have been described above, but the present inventors believe that the invention of the present inventors is not limited in any detail of the description unless otherwise specified, and should not be violated. The invention is broadly construed in the context of the spirit and scope of the invention as set forth in the appended claims.

This application claims priority based on Japanese Patent Application No. 2010-84447, which filed a patent application in Japan on March 31, 2010, and Japanese Patent Application No. 2010-84531, which filed a patent application in Japan on March 31, 2010. The contents thereof are incorporated in the specification as a part of the description of the specification.

1‧‧‧Substrate resin film

2‧‧‧Adhesive layer

3‧‧‧ adhesive layer

10, 20‧‧‧Adhesive sheets for semiconductor wafer processing

Fig. 1 is a cross-sectional view showing an embodiment of an adhesive sheet for wafer processing of the present invention.

Fig. 2 is a cross-sectional view showing another embodiment of the pressure-sensitive adhesive sheet for wafer processing of the present invention.

Claims (6)

An adhesive sheet for processing a semiconductor wafer, which is formed by a radiation-permeable base resin film, an adhesive layer provided on the base resin film, and an adhesive layer provided on the adhesive layer, The adhesive layer is composed of a layer containing a radiation curable resin composition containing (iii) the photopolymerization initiator (b) in an amount of 0.1 to 10 parts by mass based on 100 parts by mass of the (i-1) base resin. -1) a base resin in which an acrylic polymer (a) having a residue having a (meth)acrylic monomer portion as a main component is bonded to a repeating unit of a main chain, and the (meth)acrylic acid is used as a main component. The monomer portion has a radiation-curable carbon-carbon double bond-containing group, the acrylic polymer (a) has an iodine value of 20 to 55, and the (iii) photopolymerization initiator (b) is infiltrated by a gel. a chromatography (hereinafter referred to as "GPC") method in which the weight average molecular weight in terms of polystyrene as a standard material is less than 1000; the adhesive is composed of at least an epoxy resin and an imidazole compound; the photopolymerization initiator ( b) is selected from the group consisting of 1-hydroxy-cyclohexylphenyl-one, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-methyl-1-( 4-methylthiophenyl)-2- Lolinylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, oligo{2-hydroxy-2-methyl-1-[4-(1-methylvinyl Phenyl]acetone} (repeating number = 2 to 3), and an oligomer represented by the following formula (1): (1) (in the formula, R represents an alkyl group, and n is an integer of 2 to 4), at least one of the group consisting of. The adhesive sheet for semiconductor wafer processing according to claim 1, wherein the imidazole compound is selected from the group consisting of 2-methylimidazole, 2-ethyl-4-methylimidazole, and 1-cyanoethyl-2-benzene. A compound of 1-cyanoethyl-2-phenyl imidazolium trimellitate. The adhesive sheet for semiconductor wafer processing according to claim 1 or 2, wherein the acrylic polymer (a) of the adhesive layer is made of the following acrylic copolymer and 2-methylpropenyloxy B. A polymer obtained by reacting a isocyanate, which is composed of butyl acrylate, 2-hydroxyethyl acrylate, and acrylic acid. An adhesive sheet for processing a semiconductor wafer, which is formed by a radiation-permeable base resin film, an adhesive layer provided on the base resin film, and an adhesive layer provided on the adhesive layer, The adhesive layer is used in an amount of 1 to 300 parts by mass based on (ii) the compound (c), and (iii) the photopolymerization initiator (b) 0.1 to 10 by mass based on 100 parts by mass of the (i-2) acrylic polymer. a layer of a radiation curable resin composition, wherein the acrylic polymer contained in the radiation curable resin composition constituting the adhesive layer contains at least n-butyl acrylate as a monomer component, and (ii) a compound (c) a photopolymerization initiator (b) having at least two photopolymerizable carbon-carbon double bonds in the molecule having a weight average molecular weight of 10,000 or less, which is referred to as gel permeation chromatography (hereinafter referred to as The "GPC" method has a weight average molecular weight of less than 1000 in terms of polystyrene as a standard material; the adhesive is composed of at least an epoxy resin and an imidazole compound; and the photopolymerization initiator (b) is selected from 1-hydroxy-cyclohexylphenyl-one, 2,2-dimethoxy-1,2-diphenylethane 1-ketone, 2-methyl-1-(4-methylthiophenyl)-2- Lolinylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, oligo{2-hydroxy-2-methyl-1-[4-(1-methylvinyl Phenyl]acetone} (repeating number = 2 to 3), and an oligomer represented by the following formula (1) (in the formula, R represents an alkyl group, and n is an integer of 2 to 4), at least one of the group consisting of. Adhesive for semiconductor wafer processing as claimed in item 4 of the patent application a tablet, wherein the imidazole compound is selected from the group consisting of 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazole A compound of a phthalic acid. The adhesive sheet for semiconductor wafer processing according to claim 4 or 5, wherein the base resin of the adhesive layer is acrylic acid composed of at least one selected from the group consisting of n-butyl acrylate, ethyl acrylate and acrylic acid. Is a copolymer.