WO2011125683A1

WO2011125683A1 - Adhesive sheet for semiconductor wafer processing

Info

Publication number: WO2011125683A1
Application number: PCT/JP2011/057912
Authority: WO
Inventors: 朗矢吹; 正三矢野; 有理玉川
Original assignee: 古河電気工業株式会社
Priority date: 2010-03-31
Filing date: 2011-03-29
Publication date: 2011-10-13
Also published as: KR20150001804A; CN102714151A; KR20120092694A; SG184325A1; TW201204800A; TWI507502B

Abstract

Even when using a device that bonds a dicing sheet directly to the underside of a wafer, the disclosed adhesive sheet for semiconductor wafer processing can be easily peeled off after a dicing step is finished and can drastically reduce the adherence of contaminants. Said adhesive sheet comprises a radiotransparent resin base film and an adhesive layer formed on top of said resin base film. The adhesive layer may use a radiation-curable resin composition (I) that contains between 0.1 and 10 mass parts of a photopolymerization initiator (b), with a weight-average molecular weight less than 1,000 as measured by gel permeation chromatography calculated with polystyrene as the reference substance, per 100 mass parts of a base resin consisting primarily of a polymer (a) in which a residue, which has a (meth)acryl monomer part with a group containing a radiation-curable carbon-carbon double bond, is bonded to the main-chain repeating unit. Alternatively, the adhesive layer may use a radiation-curable resin composition (II) that contains, per 100 mass parts of a base resin: between 1 and 300 mass parts of a compound that has a weight-average molecular weight of at most 10,000, with each molecule having at least two photopolymerizable carbon-carbon double bonds; and between 0.1 and 10 mass parts of a photopolymerization initiator with a weight-average molecular weight less than 1,000 as measured by gel permeation chromatography calculated with polystyrene as the reference substance.

Description

Adhesive sheet for semiconductor wafer processing

The present invention relates to a pressure-sensitive adhesive sheet for processing a semiconductor wafer having a radiation curable pressure-sensitive adhesive layer, which is used when processing a thin semiconductor wafer.

Conventionally, a semiconductor integrated circuit has been manufactured by fixing a semiconductor chip having a predetermined circuit pattern formed on a die pad with an adhesive. The semiconductor chip used at this time is manufactured by the following method, for example.
(1) After slicing a high-purity silicon single crystal to obtain a semiconductor wafer, a predetermined circuit pattern such as an IC is formed on the wafer surface.
(2) A surface protection tape for protecting the circuit surface of the semiconductor wafer is pasted to protect the formed circuit surface, and then the back surface of the wafer is ground by a grinder to make the wafer thickness about 100 to 600 μm. Then, the surface protection tape is peeled off from the circuit surface.
(3) A dicing sheet is bonded to a ring-shaped dicing frame having a hollow portion slightly larger than the diameter of the semiconductor wafer, and the back surface of the wafer ground by the grinding machine is bonded to the adhesive layer exposed in the hollow portion of the frame. Match.
(4) Dicing from the side opposite to the surface on which the dicing sheet is bonded (that is, the side on which the circuit is formed) to form a semiconductor chip, which is irradiated with radiation such as ultraviolet rays, and the adhesive strength of the adhesive layer of the dicing sheet The chip is pushed up from the substrate film side of the dicing sheet with a needle and picked up.

The dicing sheet used in this process requires an adhesive strength that does not peel during dicing, while it is peeled from the dicing sheet with a low adhesive strength that can easily peel the semiconductor chip when picking up after dicing. It is necessary that the contaminants including the adhesive do not adhere to the back surface of the chip.
On the other hand, in recent years, it has become mainstream to obtain a thin semiconductor chip having a thickness of 100 μm or less from a large-diameter wafer having a diameter of 300 mm. Therefore, it is an important issue to obtain a semiconductor chip without any problem from this thin wafer.

As one solution to this problem, a so-called in-line manufacturing apparatus in which the above (1) to (3) are performed in a continuous apparatus, a manufacturing method in which the steps (2) and (3) are performed quickly, etc. are proposed. (For example, see Patent Documents 1 and 2). For example, in the in-line manufacturing apparatus, the grinding process of the wafer back surface in (2) and the dicing sheet bonding process to the wafer back surface in (3) are continuously performed. For this reason, the damage of the semiconductor wafer and the semiconductor chip can be reduced in the in-line manufacturing apparatus. In this apparatus, the dicing sheet is bonded before the oxide film on the back surface of the wafer is generated.
However, in the dicing sheet having the conventional pressure-sensitive adhesive layer, it was bonded after the oxide film was formed on the back surface of the wafer. The problem of not being able to peel off successfully occurred.
In the conventional manufacturing process, since the dicing sheet is bonded after the oxide film is formed on the back surface of the wafer, in this case, the dicing sheet having the conventional pressure-sensitive adhesive layer that has been successfully peeled off is similarly used in the in-line manufacturing apparatus. The problem that it could not be peeled off well even when used in the process was caused.

As another solution, there is a so-called dicing die bond sheet in which an adhesive used for fixing a semiconductor chip on a die pad is formed into a film and laminated in advance on an adhesive layer of a dicing tape. Proposed. When using this dicing die-bonding sheet, it is bonded to the back surface of the wafer in the same manner as a normal dicing sheet, but the adhesive layer is also diced together with the pressure-sensitive adhesive layer. Since the adhesive layer is bonded to this sheet, the strength of the entire tape is increased and the sheet itself has the effect of reinforcing the strength of the thin wafer. For this reason, dicing of a thin wafer can be performed well. However, after the dicing is completed, the adhesive layer must be left on the back surface of the semiconductor chip and peeled off between the adhesive layer and the adhesive layer. Therefore, a sheet using a specific radiation-curing type is used as the pressure-sensitive adhesive layer. Recently, the radiation dose after the dicing process is increased to speed up the semiconductor chip manufacturing process. However, if the radiation dose is large, the calorific value is large, and there is a problem that it is difficult to separate the adhesive layer and the pressure-sensitive adhesive layer due to heat generated in the radiation irradiation step after the dicing step.

JP 2002-343756 A JP 2004-40114 A

This invention makes it a subject to provide the adhesive sheet for semiconductor wafer processing which can peel easily after completion | finish of a dicing process also in the apparatus which bonds a dicing sheet immediately after a wafer back surface, and can reduce adhesion of a contaminant.
In addition, the present invention provides a semiconductor with an adhesive layer by easily peeling the adhesive layer and the adhesive layer in a pickup process by using an adhesive sheet for processing a semiconductor wafer in which an adhesive layer is further provided on the adhesive layer. It is an object of the present invention to provide a pressure-sensitive adhesive sheet for processing a semiconductor wafer that can obtain a chip.

As a result of intensive studies on the above problems, the present inventors have found that (I) a base resin mainly composed of a specific radiation-curable acrylic polymer and a photopolymerization initiator having a specific molecular weight on a base resin film. Containing a radiation-polymerizable compound and a photopolymerization initiator having a specific molecular weight in an adhesive sheet for processing a semiconductor wafer having a pressure-sensitive adhesive layer formed thereon, or (II) an acrylic polymer. It has been found that the above-mentioned problems can be solved by using any of the pressure-sensitive adhesive sheets for semiconductor wafer processing in which the radiation-polymerizable pressure-sensitive adhesive layer of the resin composition to be formed is used. The present invention has been made based on the findings.
That is, the present invention
<1> A radiation-permeable base resin film, and a pressure-sensitive adhesive sheet for processing a semiconductor wafer in which a pressure-sensitive adhesive layer is formed on the base resin film, wherein the pressure-sensitive adhesive layer has (i-1) main chain 100 mass of base resin mainly composed of acrylic polymer (a) in which a residue having a (meth) acrylic monomer portion having a radiation-curable carbon-carbon double bond-containing group is bonded to a repeating unit Against the department
(Iii) Radiation containing 0.1 to 10 parts by mass of a photopolymerization initiator (b) having a weight average molecular weight of less than 1000, converted to polystyrene as a standard substance by gel permeation chromatography (hereinafter referred to as “GPC”) method A pressure-sensitive adhesive sheet for processing semiconductor wafers, characterized in that it is composed of a layer using a curable resin composition;
<2> A semiconductor wafer processing pressure-sensitive adhesive sheet having a radiation transmissive base resin film and a pressure-sensitive adhesive layer formed on the base resin film, wherein the pressure-sensitive adhesive layer is (i-2) acrylic heavy For 100 parts by mass of coalesced
(Ii) 1 to 300 parts by weight of a compound (c) having at least two photopolymerizable carbon-carbon double bonds in the molecule and having a weight average molecular weight of 10,000 or less,
(Iii) Radiation containing 0.1 to 10 parts by mass of a photopolymerization initiator (b) having a weight average molecular weight of less than 1000, converted to polystyrene as a standard substance by gel permeation chromatography (hereinafter referred to as “GPC”) method A pressure-sensitive adhesive sheet for processing a semiconductor wafer, characterized in that it is composed of a layer using a curable resin composition;
<3> The photopolymerization initiator (b) contains 1-hydroxy-cyclohexylphenyl-ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-methyl-1- (4-methylthiophenyl) ) -2-morpholinopropan-1-one and an oligomer represented by the following general formula (1)

General formula (1)
(In the formula, R represents an alkyl group. N is an integer.)
<1> or <2> a pressure-sensitive adhesive sheet for processing a semiconductor wafer, which is at least one selected from the group consisting of:
<4> The pressure-sensitive adhesive sheet for processing a semiconductor wafer according to <3>, wherein the degree of polymerization of the oligomer represented by the general formula (1) is n = 2 to 4,
<5> The iodine value of the polymer (a) containing, as a constituent unit, an acrylic monomer having a radiation-polymerizable carbon-carbon double bond-containing group with respect to the repeating unit of the main chain is 1 to 50 <1>, <3> or <4> a semiconductor wafer processing adhesive sheet according to <1>, <6><1> to <5> A pressure-sensitive adhesive sheet for processing semiconductor wafers, wherein an adhesive layer is further provided on the agent layer,
Is to provide.

When the adhesive sheet for processing a semiconductor wafer of the present invention is used in an apparatus for laminating a dicing sheet immediately after the back surface of the wafer, it can be easily peeled off after the dicing process is completed, and the adhesion of contaminants can be remarkably reduced.
Moreover, the adhesive layer and the adhesive layer are easily peeled off in the pickup process by the semiconductor wafer processing adhesive sheet further provided with the adhesive layer on the adhesive layer of the present invention. Can be obtained.

The above and other features and advantages of the present invention will become more apparent from the following description with reference to the accompanying drawings as appropriate.

It is sectional drawing which shows one Embodiment of the adhesive sheet for wafer processing of this invention. It is sectional drawing which shows other one Embodiment of the adhesive sheet for wafer processing of this invention.

A preferred adhesive sheet for processing a semiconductor wafer of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing a preferred embodiment of an adhesive sheet for processing a semiconductor wafer of the present invention, in which a base resin film 1 and an adhesive layer 2 are formed on the base resin film 1. FIG. 2 is a schematic sectional view showing another preferred embodiment of the pressure-sensitive adhesive sheet for processing semiconductor wafers of the present invention. In FIG. 2, the adhesive layer 2 is formed on the base resin film 1, the base resin film 1, and the adhesive layer 3 is further formed.

The pressure-sensitive adhesive layer in the present invention is composed of a radiation curable resin composition in which a specific photopolymerization initiator is contained in a specific blending amount together with a specific blending amount of a radiation polymerizable compound in a base resin. Using the pressure-sensitive adhesive sheet for processing a semiconductor wafer of the present invention, after the dicing process is completed, radiation is irradiated from the side of the below-described radiation-transmissive base resin film to reduce the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer. As a result, the semiconductor chip can be picked up without any problem. As shown in FIG. 2, the pressure-sensitive adhesive sheet for processing a semiconductor wafer in which an adhesive layer is formed on the pressure-sensitive adhesive layer is also irradiated with radiation from the side of the below-described radiation-transmissive base resin film, and the pressure-sensitive adhesive layer Reduce the adhesive strength. In this case, by peeling at the interface between the adhesive layer and the pressure-sensitive adhesive layer, a semiconductor chip with an adhesive layer can be obtained and fixed on the die pad as it is.

The adhesive sheet for semiconductor wafer processing of the present invention shown in FIG. 1 can be peeled off without any problems in the pick-up process after radiation irradiation even when it is bonded to the back surface immediately after finishing the back surface grinding of the semiconductor wafer. The surface of the semiconductor wafer immediately after the end of the grinding is an active surface in which a natural oxide film is not entirely formed and active atoms in an unoxidized state are present. Even in this case, the pressure-sensitive adhesive sheet for processing a semiconductor wafer of the present invention can be peeled off without any problem after irradiation, and the adhesion of contaminants due to the pressure-sensitive adhesive component can be remarkably reduced.
Further, the pressure-sensitive adhesive sheet for processing a semiconductor wafer according to the present invention, in which an adhesive layer is further provided on the pressure-sensitive adhesive layer, is shown in FIG. 2 by the heat generated by radiation irradiation after the dicing process is completed. There is no problem in peeling off.

In the semiconductor wafer processing sheet of the present invention, the pressure-sensitive adhesive layer is formed by using a radiation curable resin composition on a base resin film described later. The semiconductor wafer processing sheet of the present invention includes the first aspect and the second aspect. Each mode includes the mode shown in FIG. 1 and the semiconductor wafer processing sheet shown in FIG. The base resin of the pressure-sensitive adhesive layer of the semiconductor wafer processing sheet of the first embodiment is (i-1) a (meth) acrylic group having a radiation-curable carbon-carbon double bond-containing group with respect to the repeating unit of the main chain. The main component is an acrylic polymer (a) bonded with a residue having a monomer part.

(Base resin of the adhesive layer of the semiconductor wafer processing sheet of the first aspect)
The base resin of the radiation curable resin composition used for the pressure-sensitive adhesive layer of the semiconductor wafer processing sheet of the first aspect has a radiation curable carbon-carbon double bond-containing group with respect to the repeating unit of the main chain ( The polymer is mainly composed of a polymer (a) bonded with a residue having a (meth) acrylic monomer portion. In the present invention, the polymer (a) as a main component means that the content in the base resin is 50 to 100% by mass. In the present invention, the (meth) acrylic monomer includes both an acrylic monomer and a methacrylic monomer.
The polymer (a) may be produced by any method. For example, the polymer (a) includes an acrylic copolymer and / or a methacrylic copolymer having a radiation curable carbon-carbon double bond with respect to a repeating unit of the main chain and having a functional group. The thing obtained by making (a1) and the compound (a2) which has a functional group which can react with this functional group react is mentioned. Further, an acrylic copolymer and / or a methacrylic copolymer having a functional group is defined as (a1 ′), which has a radiation-curable carbon-carbon double bond and can react with the functional group of (a1 ′). A compound having a group may be (a2 ′), and these may be reacted to obtain a polymer (a).
The acrylic copolymer and / or methacrylic copolymer (a1) having a radiation curable carbon-carbon double bond and a functional group with respect to the repeating unit of the main chain is, for example, radiation curing. A monomer (a1-1) such as an alkyl acrylate and / or alkyl methacrylate having a functional carbon-carbon double bond and a monomer (a1-2) having a functional group are copolymerized. Obtainable.

As the monomer (a1-1), for example, a (meth) acrylic acid alkyl ester having 6 to 12 carbon atoms in the alkyl group of the alkyl ester (eg, hexyl acrylate, n-octyl acrylate, isooctyl acrylate, 2- Ethyl hexyl acrylate, dodecyl acrylate, decyl acrylate). In addition, (meth) acrylic acid alkyl ester having 5 or less carbon atoms in the alkyl group of the alkyl ester (for example, pentyl acrylate, n-butyl acrylate, isobutyl acrylate, ethyl acrylate, methyl acrylate, or similar methacrylates) Can be mentioned.

As the monomer (a1-1), the glass transition point tends to decrease as the alkyl ester of the alkyl ester having a larger number of carbon atoms (meth) acrylic acid alkyl ester is used. Therefore, the polymer (a) having a desired glass transition point can be obtained by appropriately selecting the carbon number of the alkyl group of the alkyl ester of the monomer (a1-1).
In addition to the glass transition point, a low molecular compound having a carbon-carbon double bond such as vinyl acetate, styrene or acrylonitrile is added to (a1-1) for the purpose of improving compatibility with other components and various performances. A polymer (a) can be obtained. The blending amount of these low molecular compounds is preferably 5% by mass or less of the monomer (a1-1).

Examples of the functional group possessed by the monomer (a1-2) include a carboxyl group, a hydroxyl group, an amino group, a cyclic acid anhydride group, an epoxy group, and an isocyanate group. Specific examples of the monomer (a1-2) include, for example, acrylic acid, methacrylic acid, cinnamic acid, itaconic acid, fumaric acid, phthalic acid, 2-hydroxyalkyl acrylates, 2-hydroxyalkyl methacrylates, glycol Monoacrylates, glycol monomethacrylates, N-methylolacrylamide, N-methylolmethacrylamide, allyl alcohol, N-alkylaminoethyl acrylates, N-alkylaminoethyl methacrylates, acrylamides, methacrylamides, maleic anhydride, Some of the isocyanate groups of itaconic anhydride, fumaric anhydride, phthalic anhydride, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and polyisocyanate compounds are hydroxyl groups or carboxyl groups. Fine radiation curable carbon - can enumerate such as those urethanization a monomer having a carbon-carbon double bond.

When the functional group (a2) is a carboxyl group or a cyclic acid anhydride group, examples of the functional group (a1) include a hydroxyl group, an epoxy group, and an isocyanate group. When the functional group (a2) is a hydroxyl group, examples of the functional group (a1) include a cyclic acid anhydride group and an isocyanate group. When the functional group (a2) is an amino group, examples of the functional group (a1) include an epoxy group and an isocyanate group. When the functional group of (a2) is an epoxy group, examples of the functional group of (a1) include a carboxyl group, a cyclic acid anhydride group, and an amino group.
As specific examples, those similar to those listed in the specific examples of the monomer (a1-2) can be listed.

In the reaction of (a1) and (a2), by leaving an unreacted functional group, the acid value or the hydroxyl value can be suitably set within a range as described later.
The polymer (a) containing as a constituent unit a (meth) acrylic monomer having a radiation-curable carbon-carbon double bond-containing group with respect to the repeating unit of the main chain can be solution-polymerized in various solvents. Can be obtained. As the organic solvent in the case of solution polymerization, a ketone, ester, alcohol, or aromatic solvent can be used. In general, it is preferable to use a good solvent for an acrylic polymer and a solvent having a boiling point of 60 to 120 ° C. For example, toluene, ethyl acetate, isopropyl alcohol, benzene, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, and the like can be used. As the polymerization initiator, radical generators such as azobis compounds such as α, α′-azobisisobutylnitrile and organic peroxide compounds such as benzoyl peroxide can be used. At this time, if necessary, a catalyst and a polymerization inhibitor can be used in combination, and the polymer (a) having a desired molecular weight can be obtained by adjusting the polymerization temperature and the polymerization time. In terms of adjusting the molecular weight, it is preferable to use a mercaptan or carbon tetrachloride solvent. The synthesis of the polymer (a) is not limited to solution polymerization, and other methods such as bulk polymerization and suspension polymerization may be used.

In the present invention, the weight average molecular weight of the polymer (a) in which a residue having a (meth) acrylic monomer part having a radiation-curable carbon-carbon double bond-containing group is bonded to a repeating unit of the main chain Is preferably about 300,000 to 1,000,000. If it is less than 300,000, the cohesive force due to radiation irradiation becomes small, and when the wafer is diced, the device is likely to be displaced, and image recognition may be difficult. In order to prevent the deviation of the element as much as possible, the molecular weight is preferably 400,000 or more. Further, if the molecular weight exceeds 1,000,000, there is a possibility of gelation at the time of synthesis and coating. The weight average molecular weight of the polymer (a) in the present invention can be determined, for example, as a weight average molecular weight in terms of polystyrene by the following method.
(Measurement conditions for weight average molecular weight)
GPC device: HLC-8120GPC (trade name, manufactured by Tosoh Corporation)
Column: TSK gel SuperHM-H / H4000 / H3000 / H2000 (trade name, manufactured by Tosoh Corporation)
Flow rate: 0.6 ml / min,
Concentration: 0.3% by mass
Injection volume: 20 μl,
Column temperature: 40 ° C
Developing solvent: Chloroform

In the present invention, it is preferable that the iodine value of the polymer (a) containing an acrylic monomer having a radiation-polymerizable carbon-carbon double bond-containing group with respect to the main chain as a structural unit is 1 to 50. More preferably, it is 2 to 30, and if it is less than 1, the degree of cross-linking after radiation irradiation is so small that the peeling force cannot be lowered, so that the chip cannot be sufficiently picked up. If it exceeds 50, the degree of cross-linking after irradiation is high and curing shrinkage occurs, and the pick-up property of the chip decreases.

When the hydroxyl value of the polymer (a) is 5 to 100, it is preferable because the risk of pick-up mistakes can be further reduced by reducing the adhesive strength after irradiation. The acid value of the polymer (a) is preferably 0.5 to 30.
Here, the hydroxyl value and the acid value are values measured by JIS K 0070. By setting the hydroxyl value of the polymer (a) within an appropriate range, the fluidity of the pressure-sensitive adhesive layer after irradiation can be set within an appropriate range, and the adhesive strength after irradiation is sufficiently reduced. be able to. By setting the acid value of the polymer (a) within an appropriate range, the fluidity of the pressure-sensitive adhesive layer after irradiation can be set within an appropriate range, and the tape recoverability can be satisfied.

The base resin used in the radiation curable resin composition constituting the pressure-sensitive adhesive layer of the present invention may be blended with conventional ones within a range that does not impair the gist of the present invention. For example, natural rubber, rubber-based polymers such as various synthetic rubbers, or poly (meth) acrylic acid alkyl ester, (meth) acrylic acid alkyl ester, (meth) acrylic acid alkyl ester and other non-polymerizable copolymers thereof. Acrylic copolymers such as copolymers with saturated monomers can be used.

(Base resin of adhesive layer of semiconductor wafer processing sheet of second aspect)
The base resin of the radiation curable resin composition used for the adhesive layer of the semiconductor wafer processing sheet according to the second aspect is an acrylic polymer.
As an acrylic polymer, a (meth) acrylic acid ester component is a monomer main component (mass% in the polymer exceeds 50%), and the (meth) acrylic acid ester component can be copolymerized. Examples include those obtained by copolymerization with monomer components.

In the acrylic polymer, examples of the (meth) acrylic acid ester component as the main monomer component include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and isopropyl (meth) acrylate. Butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, (meth) Heptyl acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, (meth) ) Isodecyl acrylate, undecyl (meth) acrylate, (meth) acrylic (Meth) acrylic acid such as dodecyl, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate Examples include alkyl esters; (meth) acrylic acid cycloalkyl esters such as (meth) acrylic acid cyclohexyl; and (meth) acrylic acid aryl esters such as phenyl (meth) acrylate. (Meth) acrylic acid esters can be used alone or in combination of two or more.

(Curing agent)
In the radiation-curable resin composition constituting the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet for semiconductor wafer processing according to the first aspect and the second aspect, a polyisocyanate compound, an alkyl etherified melamine compound, an epoxy compound, and a silane cup Conventional curing agents such as ring agents can be included. By setting it as the resin composition which mix | blended the hardening | curing agent, the initial stage adhesive force can be set to arbitrary values. Among the curing agents, it is preferable to use an isocyanate curing agent.
Specific examples of the isocyanate curing agent include polyvalent isocyanate compounds such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylene diisocyanate, diphenylmethane. -4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, Lysine isocyanate and the like are used.

(Compound having at least two photopolymerizable carbon-carbon double bonds in the molecule and a weight average molecular weight of 10,000 or less)
The radiation curable resin composition used for the pressure-sensitive adhesive layer of the semiconductor wafer processing sheet according to the second aspect has a weight average molecular weight of 10,000 or less having at least two photopolymerizable carbon-carbon double bonds in the molecule. The compound (c) is contained. The compound (c) can be used without particular limitation as long as it can be cured by irradiation with radiation to form a three-dimensional network. This 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 exceeding 10,000. The molecular weight is 5,000 or less and the number of radiation-polymerizable carbon-carbon double bonds in the molecule is 2 to 6 so that the three-dimensional network of the pressure-sensitive adhesive layer can be efficiently formed by irradiation with radiation. Those are preferred.
In the present invention, the weight average molecular weight of the low molecular weight compound having at least two photopolymerizable carbon-carbon double bonds in the molecule is the polystyrene equivalent measured by GPC (gel permeation chromatography) under the following conditions. It refers to the weight average molecular weight.
(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: 1 ml / min
Concentration: 0.2 mg / ml
Injection volume: 100 μl,
Thermostatic bath temperature: 40 ° C
Mobile phase: Chloroform

Examples of the radiation polymerizable compound (c) include trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1, Examples include 4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, organopolysiloxane composition, commercially available oligoester acrylate, and urethane acrylate.

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 may be used alone or in combination of two or more. The blending amount is 1 to 300 parts by mass with respect to 100 parts by mass of the base resin. Preferably, the amount is 30 to 200 parts by mass, and more preferably 50 to 150 parts by mass with respect to 100 parts by mass of the base resin. If the amount is too small, three-dimensional reticulation by irradiation of the pressure-sensitive adhesive layer becomes insufficient, the semiconductor wafer processing pressure-sensitive adhesive sheet becomes difficult to peel from the wafer, and the wafer may be contaminated. If this amount is too large, the polymerization reaction due to radiation proceeds excessively and curing shrinkage due to radiation irradiation occurs. As a result, the pressure-sensitive adhesive layer follows the surface of the adherend and becomes difficult to pick up when picking up the semiconductor chip after dicing. Moreover, when there is too much quantity of a radiation polymerizable compound, there exists a problem that it becomes difficult to hold | maintain the shape of an adhesive layer and thickness accuracy worsens.

(Photopolymerization initiator)
In the radiation curable resin composition constituting the pressure-sensitive adhesive layer of the semiconductor wafer processing pressure-sensitive adhesive sheet of the first aspect and the second aspect, polystyrene is standardized by a gel permeation chromatography (hereinafter referred to as “GPC”) method. A photopolymerization initiator having a weight average molecular weight converted to a substance of less than 1000 is used. 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: 1 ml / min,
Concentration: 1 mg / ml,
Injection volume: 50 μl,
Column temperature: 40 ° C
Developing solvent: Chloroform

The photopolymerization initiator generates radicals when irradiated with radiation such as light or ultraviolet rays. As a result, the polymer (a) containing a (meth) acrylic monomer having a radiation-curable carbon-carbon double bond-containing group as a constituent unit with respect to the repeating unit of the main chain contained in the pressure-sensitive adhesive layer. The curing reaction is promoted or the curing reaction of a compound having at least two photopolymerizable carbon-carbon double bonds in the molecule contained in the pressure-sensitive adhesive layer and having a weight average molecular weight of 10,000 or less is promoted. If the weight average molecular weight by GPC in terms of polystyrene of the photopolymerization initiator is too large, there will be a problem in the dispersion of the photopolymerization initiator in the pressure-sensitive adhesive layer, and it will be difficult for the generated radicals to move quickly and the efficiency of A good curing reaction cannot proceed. In this case, it becomes necessary to irradiate radiation with higher illuminance than necessary, and it becomes difficult to effectively reduce the adhesion between the pressure-sensitive adhesive layer and the adherend due to heat generation.
The phenomenon in that case will be described with reference to the drawings. As shown in FIG. 1, in the case of the adhesive sheet 10 for processing a semiconductor wafer in which the adhesive layer 2 is formed on the base resin film 1, The pickup will be hindered. As shown in FIG. 2, in the case of the pressure-sensitive adhesive sheet 20 for processing a semiconductor wafer in which the pressure-sensitive adhesive layer 2 is provided on the base resin film 1 and the adhesive layer 3 is further formed, the adhesive layer 3 and the pressure-sensitive adhesive are used. It becomes difficult to smoothly peel off the layer 2.
The upper limit of the weight average molecular weight by GPC in terms of polystyrene of the photopolymerization initiator is preferably 800, more preferably 600.

The lower limit of the weight average molecular weight by GPC in terms of polystyrene of the photopolymerization initiator is not particularly limited, but is preferably 200 or more. When the molecular weight is small, it becomes easy to sublimate, and the shift from the pressure-sensitive adhesive layer to the non-adherent layer becomes remarkable, so that the wafer is easily contaminated. In addition, the heat resistance of the pressure-sensitive adhesive layer is deteriorated, and the pressure-sensitive adhesive layer is easily decomposed in the drying step after the base material is coated during production. Therefore, a stable curing reaction may not be exhibited.

Examples of the photopolymerization initiator include benzophenone, 4,4-bis (diethylamino) benzophenone, 2,4,6-trimethylbenzophene, 4-phenylbenzophenone, t-butylanthraquinone, 2-ethylanthraquinone, diethoxyacetophenone, 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-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -Butano -1, diethylthioxanthone, isopropylthioxanthone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2-hydroxy-1- {4- [4- ( 2-hydroxy-2-methylpropionyl) benzyl] phenyl} -2-methylpropan-1-one, 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4- Morpholinyl) phenyl] -1-butanone,
Examples include oligomers represented by the following general formula (1).

General formula (1)
(In the formula, R represents an alkyl group. N is an integer.)

Among the above photopolymerization initiators, 2,2-dimethoxy-1,2-diphenylethane-1-one (molecular weight 260), 2 is an excellent photopolymerization initiator that hardly sublimes and hardly generates a residue of contamination. -Methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (molecular weight 280), 1-hydroxy-cyclohexylphenyl-ketone (molecular weight 205).
The oligomer of the general formula (1) preferably has a polymerization degree n = 2 to 4 (molecular weight 400 to 700), and more preferably has a polymerization degree n = 2 to 3 (molecular weight 400 to 500).

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

2-Methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one

The photopolymerization initiator is blended in an amount of 0.1 to 10 parts by mass with respect to 100 parts by mass of the base resin in the radiation curable resin composition constituting the pressure-sensitive adhesive layer of the semiconductor wafer processing pressure-sensitive adhesive sheet of the first aspect. Preferably, 1 to 10 parts by mass is blended with respect to 100 parts by mass of the base resin, and more preferably 2 to 7 parts by mass. In the radiation curable resin composition constituting the pressure-sensitive adhesive layer of the semiconductor wafer processing pressure-sensitive adhesive sheet of the second aspect, 0.1 to 10 parts by mass is blended with 100 parts by mass of the acrylic polymer. Preferably, 1 to 10 parts by mass is blended with 100 parts by mass of the acrylic polymer, and more preferably 2 to 7 parts by mass.
When the amount of the photopolymerization initiator is too small, the pressure-sensitive adhesive layer is not sufficiently three-dimensionally formed by irradiation with radiation, and cannot be peeled off from the adhesive layer well, or the semiconductor chip is contaminated. Moreover, when there are too many photoinitiators, the effect corresponding to it may not be acquired, but there exists a possibility that this photoinitiator may remain on a wafer.
If necessary, two or more of the above photopolymerization initiators may be used in combination. The weight average molecular weight by each GPC of the photoinitiator used should just be less than 1000. Also, amine compounds such as triethylamine, tetraethylpentamine, dimethylaminoethanol, and thioxanthone photopolymerization initiators can be used in combination as photopolymerization accelerators.

The radiation curable resin composition may contain a tackifier, a tackifier, a surfactant, other modifiers and conventional components as necessary to adjust the adhesion to the semiconductor wafer. However, since surfactants and compounds showing surface activity may contaminate the semiconductor wafer, it is preferable to use as few as possible.

In the present invention, on the base resin film, the above base resin, a compound having at least two photopolymerizable carbon-carbon double bonds in the molecule and a weight average molecular weight of 10,000 or less, specific photopolymerization initiation A radiation-polymerizable resin composition containing an agent, and if necessary, a crosslinking agent and other compounding ingredients, is directly applied and dried by heating, or once applied to release paper and dried, and then transferred onto a base resin film. By this, the adhesive sheet for semiconductor wafer processing by which the adhesive layer was comprised by the layer using a radiation polymerizable resin composition can be manufactured.
There is no restriction | limiting in particular in the thickness of an adhesive layer. Usually, the pressure-sensitive adhesive layer is formed so that the thickness of the pressure-sensitive adhesive layer is usually 5 to 100 μm to obtain a pressure-sensitive adhesive sheet for processing semiconductor wafers such as sheets and tapes.
As the radiation, alpha rays, gamma rays, electron beams, ultraviolet rays, and the like can be used, and there is no particular limitation as long as the adhesive strength can be reduced by curing the adhesive layer. Electron beams and ultraviolet rays are preferred, and ultraviolet rays are more preferred when a photopolymerization initiator is used.

As shown in FIG. 2, as the pressure-sensitive adhesive sheet for processing a semiconductor wafer of the present invention, a pressure-sensitive adhesive layer 2 may be provided on a base resin film 1, and an adhesive layer 3 may be further formed thereon. The method for forming the pressure-sensitive adhesive layer and then the adhesive layer on the base resin film is not particularly limited. According to the conventional method, the pressure-sensitive adhesive layer is laminated on the base resin film, and further the adhesive on the pressure-sensitive adhesive layer. What is necessary is just to laminate | stack a layer.
In this case, the adhesive sheet for semiconductor wafer processing is bonded to the back surface of the semiconductor wafer after grinding, and then the adhesive and the adhesive are simultaneously cut by dicing from the circuit forming surface side of the semiconductor wafer. And a semiconductor chip with an adhesive layer can be obtained. As the adhesive used for the adhesive layer 3, a conventional adhesive can be used.

As the adhesive layer, an adhesive layer formed in advance can be used. For example, conventional polyimide resin, polyamide resin, polyetherimide resin, polyamideimide resin, polyester resin, polyesterimide resin, phenoxy resin, polysulfone resin, polyethersulfone resin, polyphenylene sulfide resin, polyether ketone used for adhesives Resins, chlorinated polypropylene resins, acrylic resins, polyurethane resins, epoxy resins, polyacrylamide resins, melamine resins, and the like, and mixtures thereof can be used.
Among these, it is particularly preferable to use an epoxy resin in terms of good heat resistance after curing. Any epoxy resin that cures and exhibits an adhesive action may be used. In order to increase the glass transition temperature (Tg) and ensure the heat resistance of the adhesive layer, a polyfunctional epoxy resin may be added. Examples of the polyfunctional epoxy resin include phenol novolac type epoxy resins and cresol novolac type epoxy resins. The epoxy resin curing agent is not particularly limited as long as it is usually used as a curing agent. One molecule of amine compound, polyamide, acid anhydride, polysulfide, boron trifluoride, phenolic hydroxyl group is used. Examples thereof include bisphenol A, bisphenol F, and bisphenol S, which are compounds having two or more compounds.
In particular, it is preferable to use phenol novolac resin, bisphenol novolac resin, or the like, which is a phenol resin, because of its excellent resistance to electric corrosion during moisture absorption. Moreover, it is preferable to use a curing accelerator together with the curing agent in terms of shortening the heat treatment time for curing. As curing accelerators, bases such as various imidazoles such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate are used. it can.

Also, it is desirable to add a silane coupling agent or a titanium coupling agent as an additive to the resin or a mixture thereof in order to enhance the adhesion to the semiconductor chip or the lead frame. Further, a filler may be added for the purpose of improving heat resistance and adjusting fluidity. As such a filler, for example, silica, alumina, antimony oxide, and the like can be used. These fillers can be used by mixing at an arbitrary ratio as long as the maximum particle size is smaller than the thickness of the adhesive layer.

The thickness of the adhesive layer is not particularly limited, but is usually preferably about 5 to 100 μm. Moreover, you may laminate | stack an adhesive bond layer on the whole surface of the adhesive layer of an adhesive film. Moreover, you may laminate | stack the adhesive layer cut | disconnected (pre-cut) in the shape according to the semiconductor wafer previously bonded together in a part of adhesive layer. In this case, there is an adhesive layer in the part where the semiconductor wafer is bonded, and there is no adhesive layer in the part where the ring frame for dicing is bonded, and only the pressure-sensitive adhesive layer of the adhesive film is present. By adopting this shape, the pressure-sensitive adhesive layer is bonded to the ring frame, and usually the adhesive layer that is difficult to peel off from the adherend is not bonded, so the pressure-sensitive adhesive sheet for semiconductor wafer processing of the present invention is used after use It can be easily peeled from the ring frame.

The adhesive sheet for processing a semiconductor wafer of the present invention requires that the base resin film be radiation transparent in order to cure the adhesive layer by irradiating radiation from the base resin film side at the time of peeling. Further, when processing a wafer, it receives an impact by a cutting blade or the like and receives a pressure from cleaning water or the like. For this reason, a base resin film has the intensity | strength which can endure these, and the material and thickness suitable for these are selected. The surface of the base resin film on which the pressure-sensitive adhesive layer is formed is preferably subjected to various surface treatments including corona treatment in order to make the pressure-sensitive adhesive layer difficult to peel from the base resin film.

Materials used for the base resin film include polyethylene, polypropylene, ethylene-propylene copolymer, polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, ethylene-vinyl acetate copolymer, polybutene-1 And films of poly-4-methylpentene-1, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-acrylic acid copolymer, polyurethane, polymethylpentene, polybutadiene and the like. it can.
The thickness of the base resin film is 30 to 500 μm, preferably 40 to 300 μm, more preferably 50 to 200 μm. If this thickness is too thin, the strength will be weakened, which may cause problems due to breakage or the like during semiconductor wafer processing.
On the other hand, if the base resin film is too thick, the semiconductor wafer processing pressure-sensitive adhesive sheet is too hard in the pick-up process of the semiconductor chip after the dicing process is completed, which causes a problem in pushing up with the needle. Moreover, the dicing process is completed, and it becomes difficult to sufficiently stretch the semiconductor wafer processing pressure-sensitive adhesive sheet in the expanding process before the pickup process. For this reason, the gap between the semiconductor chips is small, the chip recognizability by the image is insufficient, and the pickup failure of the semiconductor chip occurs.

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

A. Radiation curable Preparation of radiation curable resin composition used for pressure-sensitive adhesive layer of pressure-sensitive adhesive tape for semiconductor wafer processing of the first aspect (1) Having a radiation-curable carbon-carbon double bond-containing group with respect to the repeating unit of the main chain Preparation of a polymer in which a residue having a (meth) acrylic monomer part is bonded Acrylic copolymer using butyl acrylate (59 mol%), 2-hydroxyethyl acrylate (25 mol%) and acrylic acid (16 mol%) A coalescence was produced. Reaction of 2-hydroxyethyl acrylate side chain terminal OH group of this acrylic copolymer with NCO group of 2-methacryloyloxyethyl isocyanate to produce a radiation curable carbon-carbon double bond to the repeating unit of the main chain The polymer which combined the residue which has the (meth) acrylic-type monomer part which has a containing group was obtained. At this time, polymers ((a1) to (a4)) having different double bond amounts were obtained by appropriately changing the dropping amount of 2-isocyanatoethyl methacrylate. The obtained polymers ((a1) to (a4)) all 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 value of the polymer (a1) used in Examples 1-1 to 1-9 and 1-11 and Comparative Examples 1-1 to 1-4 and 1-7 is It was 20. The iodine value of the polymer (a2) used in Example 1-10 was 50, the iodine value of the polymer (a3) used in Example 1-12 was 0.5, and the weight used in Example 1-13 was The iodine value of combined (a4) was 55.
In the following description, the polymer ((a1) to (a4)) will be described as the polymer (a).
(I) Weight average molecular weight About the polymer (a), the weight average molecular weight was measured by GPC of the following conditions.
GPC device: HLC-8120GPC (trade name, manufactured by Tosoh Corporation)
Column: TSK gel SuperHM-H / H4000 / H3000 / H2000 (trade name, manufactured by Tosoh Corporation)
Flow rate: 0.6 ml / min,
Concentration: 0.3% by mass
Injection volume: 20 μl,
Column temperature: 40 ° C
Developing solvent: Chloroform (ii) Glass transition temperature Differential scanning calorimeter (DSC) (DSC7020 (trade name), manufactured by Seiko Instruments Inc.), using a differential scanning calorimeter (DSC), the rate of temperature increase is 5 Measured at ° C / min.
(Iii) Double bond amount Iodine value was determined according to JIS K 0070.

(2) Preparation of radiation curable resin composition 100 parts by mass of the polymer (a) obtained in (1) was blended with a photoinitiator in the number of parts described in Table 1-1 to Table 1-4. Preparation of radiation curable resin compositions described in Examples and Comparative Examples in Table 1-1 to Table 1-4 by blending 3 parts by mass of a polyisocyanate compound (trade name Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) as a curing agent. did. As a photoinitiator used in Comparative Examples 1-1 and 1-7, VPE-0201 (trade name, manufactured by Wako Pure Chemical Industries, Ltd.) was used as the polyethylene glycol unit-containing polymer azo polymerization initiator.
The weight average molecular weight of the photoinitiator was measured by the GPC method, and the weight average molecular weight was calculated using polystyrene as a standard substance. The results are also shown in Tables 1-1 to 1-4. As gel permeation chromatography, OligoPore 300 × 7.5 (trade name) manufactured by Polymer Laboratories was used. The developing solvent was chloroform, and the measurement was performed at 40 ° C.

2. Preparation of radiation curable resin composition for adhesive tape for processing semiconductor wafer of second aspect (1) Acrylic polymer constituting adhesive layer 85 parts by mass of n-butyl acrylate, 10 parts by mass of ethyl acrylate and acrylic An acrylic copolymer was prepared as a base resin constituting the pressure-sensitive adhesive layer using 5 parts by mass of acid. The weight average molecular weight was 600,000.

(2) Compound UN-3320HA (trade name, manufactured by Negami Kogyo Co., Ltd.) 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-9000PEP (trade name, Negami) Kogyo), UN-6050 PTM (trade name, manufactured by Negami Kogyo), UN-901T (trade name, manufactured by Negami Kogyo), UN-9200A (trade name, manufactured by Negami Kogyo) were used.
The weight average molecular weight and double bond amount in terms of polystyrene of the used compound were measured by the following methods. The results were as follows.
UN-3320HA (trade name, manufactured by Negami Kogyo): 1500 (double bond amount: 6)
UN-3320HC (trade name, manufactured by Negami Kogyo): 1500 (double bond amount: 6)
UN-9000PEP (trade name, manufactured by Negami Kogyo): 5000 (double bond amount: 2)
UN-6050PTM (trade name, manufactured by Negami Kogyo): 6000 (double bond amount: 2)
UN-901T (trade name, manufactured by Negami Kogyo): 4000 (double bond amount: 9)
UN-9200A (trade name, manufactured by Negami Kogyo): 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: 1 ml / min
Concentration: 0.2 mg / ml
Injection volume: 100 μl,
Thermostatic bath temperature: 40 ° C
Mobile phase: Chloroform (measurement method of double bond amount)
The amount of double bonds was calculated from the iodine value obtained by JIS K 0070.

(3) Preparation of radiation curable resin composition In 100 parts by mass of the base resin of (1), the number of parts described in Table 2-1 to Table 2-4, and the photopolymerizable carbon in the molecule described in (2) A compound having a weight average molecular weight of 10,000 or less having at least two carbon double bonds and a photoinitiator are blended, and further 3 parts by mass of a polyisocyanate compound (trade name Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) is blended as a curing agent. Then, radiation curable resin compositions described in Examples and Comparative Examples in Table 2-1 to Table 2-4 were prepared. As the photoinitiator used in Comparative Examples 2-1 and 2-6, VPE-0201 (trade name, manufactured by Wako Pure Chemical Industries, Ltd.) was used as the polyethylene glycol unit-containing polymer azo polymerization initiator.
The weight average molecular weight of the photoinitiator was measured by a gel permeation chromatography (GPC) method, and the weight average molecular weight was calculated using polystyrene as a standard substance. The results are also shown in Tables 2-1 to 2-4. As gel permeation chromatography, OligoPore 300 × 7.5 (trade name) manufactured by Polymer Laboratories was used. The developing solvent was chloroform, and the measurement was performed at 40 ° C.

B. Preparation of pressure-sensitive adhesive sheet for semiconductor wafer processing (I)
A base resin film having a thickness of 100 μm was produced by T-die method using EMMA resin (trade name, trade name: ACRIFT WD201 manufactured by Sumitomo Chemical Co., Ltd.). To this base resin film, Examples 1-1 to 1-10, 1-12 to 1-13, 2-1 to 2-10, Comparative Examples 1-1 to 1-4, 2-1 to 2-5 The radiation curable resin composition shown in 1 was applied and cured appropriately. Thereby, the adhesive sheet for semiconductor wafer processing of the structure shown in FIG. 1 which has an adhesive layer whose film thickness after drying is 10 micrometers was obtained.

3. Preparation of adhesive sheet for semiconductor wafer processing (II)
(1) Adjustment of adhesive composition constituting adhesive layer 3 parts by mass of γ-mercaptopropyltrimethoxysilane as a silane coupling agent with respect to 50 parts by mass of cresol novolac type epoxy resin as epoxy resin and 50 parts by weight of phenol resin Cyclohexanone was added to a composition consisting of 5 parts by weight of γ-ureidopropyltriethoxysilane and 30 parts by weight of spherical silica as a filler, mixed with stirring, and further kneaded for 90 minutes using a bead mill.
Add 300 parts by weight of acrylic rubber (weight average molecular weight 150,000) and 1 part by weight of 1-cyanoethyl-2-phenylimidazole as a curing accelerator to the above composition, stir and mix, vacuum degas, and adhesive composition I got a thing.

(2) Production of pressure-sensitive adhesive sheet for semiconductor wafer processing The adhesive composition obtained in (1) was applied on a polyethylene terephthalate film (release film) having a release treatment of 35 μm in thickness, and heated at 140 ° C. for 5 minutes. It dried and the adhesive sheet in which the adhesive bond layer was formed on the mold release film of the B stage state whose film thickness is 20 micrometers was obtained.
Next, 2. Radiation-polymerizability described in Examples 1-11 and Comparative Examples 1-7 in Table 1-4 on a base resin film in the same manner as described in the preparation of a semiconductor wafer processing pressure-sensitive adhesive sheet (I) A pressure-sensitive adhesive sheet for processing a semiconductor wafer having a structure shown in FIG. 1 in which a pressure-sensitive adhesive layer was formed using the resin composition was obtained. This pressure-sensitive adhesive layer and the adhesive layer of the adhesive sheet produced by the method described above are laminated and laminated, and a pressure-sensitive adhesive sheet in which a release film is laminated on a semiconductor wafer processing pressure-sensitive adhesive sheet having the configuration shown in FIG. 1-11 and Comparative Example 1-7) were obtained.
Separately, 2. Examples 2-11 to 2-15 in Table 2-4, Comparative Example 2-6, and Comparative Example 2-6 on the base resin film in the same manner as described in the preparation of the adhesive sheet for semiconductor wafer processing (I) Using the radiation-polymerizable resin composition described in 2-7, an adhesive sheet for processing semiconductor wafers having a structure shown in FIG. This pressure-sensitive adhesive layer and the adhesive layer of the adhesive sheet produced by the method described above are laminated and laminated, and a pressure-sensitive adhesive sheet in which a release film is laminated on a semiconductor wafer processing pressure-sensitive adhesive sheet having the configuration shown in FIG. 2-11 to 2-15 and Comparative Examples 2-6 and 2-7).
In the following tests, the release film was peeled off and bonded to a semiconductor wafer for evaluation.

4). Performance test Dicing was performed under the following conditions, and then the pickup property and chip contamination were evaluated.
(Dicing conditions)
(1) Adhesive sheets for processing semiconductor wafers having the structure shown in FIG. 1 Examples 1-1 to 1-10, 1-12, 1-13, 2-1 to 2-10, Comparative Examples 1-1 to 1-4, Regarding 2-1 to 2-5, using “DFD-840” manufactured by DISCO, the back surface of the silicon wafer was ground by 30 μm with two axes, and then ground so that the final thickness of the silicon wafer was 100 μm. The grinding conditions at that time were as follows.
1 axis: 350 grinding wheel (rotation speed: 4800 rpm, down speed: P1: 3.0 μm / sec, P2: 2.0 μm / sec)
Biaxial: # 2000 grinding wheel (rotation speed: 5500 rpm, down speed: P1: 0.8 μm / sec, P2: 0.6 μm / sec)

Within 5 minutes after the backside grinding, the adhesive sheet for semiconductor wafer processing having the configuration shown in FIG. 1 is adhered and fixed to an 8-inch ring frame, and the adhesive sheet for semiconductor wafer processing is attached to the adhesive sheet for semiconductor wafer processing. Inch silicon wafers were bonded and full-cut dicing was performed to a chip size of 5 mm × 5 mm using a dicing apparatus DAD340 (trade name) manufactured by DISCO. In this case, the cutting depth of the blade from the adhesive sheet surface for processing a semiconductor wafer was 30 μm in the case of the adhesive sheet having the configuration shown in FIG.

(2) Adhesive sheet for processing semiconductor wafers having the structure shown in FIG. 2 For Examples 1-11 and 2-11 to 2-15 and Comparative Examples 1-7, 2-6, and 2-7, 8 inch silicon having a thickness of 100 μm A semiconductor wafer processing pressure-sensitive adhesive sheet having the configuration shown in FIG. 2 was bonded to the wafer at 70 ° C. for 20 seconds, and then diced using DFD 6340 manufactured by Disco Corporation under the following conditions.
Dicing blade (thin rotary grindstone): 1st Disco 27HEEE 2nd Disco 27HEDD
Blade rotation speed: 35000rpm
Blade feed rate: 50mm / s
Chip size: 5mm x 5mm
Cutting depth:
First time 50μm to silicon wafer
2nd time 40 μm to semiconductor wafer processing adhesive sheet (base resin film thickness 100 μm, adhesive layer thickness 10 μm, adhesive layer thickness 20 μm)

4-1. Pickup 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, 21-11 to 2-15 and Comparative Examples 1-7, 2-6, and 2-7. After dicing under the conditions shown in (1) and (2), respectively, using an ultraviolet irradiator of a high-pressure mercury lamp lamp, the irradiation dose is 200 mJ / cm from the base resin film surface side of the adhesive sheet for semiconductor wafer processing. Then, ultraviolet rays were irradiated so as to be ^2, and thereafter, CPS-6820 (trade name) manufactured by CANON Machinery was used for expansion with an expansion stroke of 5 mm, and pickup was performed in this state. The pickup was performed using a push-up pin having a tip diameter of R250. The evaluation items were as follows.

(1) Pickup property The chip is actually picked up, and a. The tip is pushed up without problems, b. Adsorption with a circular collet, and c. We evaluated whether installation on the lead frame could be done without any problems. The evaluation was made by picking up 200 chips from an 8-inch wafer and evaluating how many chips were picked up. Those that could pick up 180 or more of the 200 chips were accepted, and Tables 1-1 to 2-4 show the number of successfully picked up chips.

(2) Chip fouling property The chip fouling property is as shown in FIG. 1 for semiconductor wafer processing adhesive sheets (Examples 1-1 to 1-10, 1-12, 1-13, 2-1 to 2-10, comparative examples) 1-1 to 1-4 and 2-1 to 2-5) were evaluated by the following methods.
(2) -1 Visual test When the above chipping property was evaluated, the chip was peeled off and visually confirmed. The case where there is no rainbow-colored gloss due to adhesion of adhesive or contamination on the back of the wafer is accepted. The case where it does is rejected, and it displayed by x.
(2) -2 Foreign matter test A semiconductor wafer processing adhesive sheet was bonded to a mirror-finished silicon wafer (6 inches) whose surface was cleaned, and the sheet was peeled off after being left for 24 hours. The number of foreign matters remaining on the wafer surface to which the sheet was bonded was measured with a laser surface inspection device (Surf Scan 6420 (trade name, manufactured by KLA Tencor Co., Ltd.). Of these, ◎ and ○ were accepted, △ was considered as a practically acceptable level, and x was rejected, and the results are shown in the table.
◎: Less than 20, ○: 20 or more and less than 90, Δ: 90 or more and less than 200, ×: 200 or more

(3) Peelability of adhesive layer and adhesive layer After placing a silicon wafer having a diameter of 5 inches on a hot plate heated to 80 ° C. and confirming that the surface temperature of the silicon wafer reached 80 ° C. The semiconductor wafer processing pressure-sensitive adhesive sheet (Examples 1-11, 2-11 to 2-15 and Comparative Examples 1-7, 2-6, 2-7) having the configuration shown in FIG. 2 was bonded in about 10 seconds. . Thereafter, the hot plate was removed, and the surface temperature of the silicon wafer bonded with the semiconductor wafer processing adhesive sheet was lowered to room temperature.
Thereafter, using a UV irradiation machine of a high-pressure mercury lamp lamp, UV irradiation was performed from the substrate resin film surface side of the semiconductor wafer processing pressure-sensitive adhesive sheet so that the irradiation amount was 200 mJ / cm ² . Thereafter, in accordance with JIS-0237, the peeling force of the semiconductor wafer processing pressure-sensitive adhesive sheet on the silicon wafer after ultraviolet irradiation was measured. The measurement conditions were 90 ° peeling and peeling speed of 50 mm / min). The case where the peeling force was 0.5 N / 25 mm or less was determined to be acceptable, and the result was ◯.

5. As shown in Tables 1-1 to 1-3, in the example evaluated for the semiconductor wafer processing adhesive sheet having the configuration shown in FIG. 1, 180 chips or more out of 200 chips were used. The semiconductor chip was able to be picked up, and there was little chip contamination and foreign matter residue, and it was possible to pick up well. In Example 1-6, chip contamination and residual number were slightly observed, but there was no practical problem.
In the case of an adhesive sheet for processing a semiconductor wafer comprising an adhesive layer using a polymer (a) having an iodine value of 0.5 as a base resin, 180 semiconductor chips out of 200 chips can be picked up. The characteristics were shown.
In contrast, when a polymer glycol azo polymerization initiator containing a polyethylene glycol unit was used as a photopolymerization initiator (Comparative Example 1-1), the photoinitiator could not be dissolved sufficiently uniformly, and the generated radicals moved sufficiently smoothly. As a result, only half of the 200 chips could be picked up.
In addition, when the amount of the photopolymerization initiator is less than 0.1 parts by mass (Comparative Examples 1-2 and 1-3), there is a problem in pick-up property due to insufficient radical supply by the initiator. In this case (Comparative Example 1-4), chip contamination was caused by sublimation with unreacted substances.

Further, as can be seen from Table 1-4, in Example 1-11, which was evaluated for the semiconductor wafer processing pressure-sensitive adhesive sheet having the structure shown in FIG. 2, interfacial delamination was successfully achieved between the pressure-sensitive adhesive layer and the adhesive layer. , All the semiconductor chips out of 200 chips could be picked up.
On the other hand, in Comparative Example 1-7, the interface peeling between the pressure-sensitive adhesive layer and the adhesive layer was not successful, and only 100 semiconductor chips out of 200 chips could be picked up.

5. As shown in Tables 2-1 to 2-3, in the example evaluated for the semiconductor wafer processing adhesive sheet having the configuration shown in FIG. 1, all the semiconductors in 200 chips were used. Chips could be picked up, and there was little chip contamination and foreign matter residue, so that it was possible to pick up well. In Example 2-6, chip contamination and residual number were slightly observed, but there was no practical problem.
In contrast, when a polymer azo polymerization initiator containing a polyethylene glycol unit was used as a photopolymerization initiator (Comparative Example 2-1), the photoinitiator could not be dissolved sufficiently uniformly, and the generated radicals moved sufficiently smoothly. As a result, only half of the 200 chips could be picked up.
In addition, when the amount of the photopolymerization initiator is less than 0.1 parts by mass (Comparative Example 2-2), there is a problem in pick-up property due to insufficient radical supply by the initiator, and when the amount is more than 10 parts by mass (comparison) In Example 2-3), chip contamination was caused by sublimation with unreacted substances.
When the number of blended parts of the compound having at least two photopolymerizable carbon-carbon double bonds in the molecule was less than 1 part by mass (Comparative Example 2-4), the pickup property was lowered. On the contrary, when the amount of the radiation-polymerizable compound is more than 300 parts by mass (Comparative Example 2-5), curing shrinkage occurs in the pressure-sensitive adhesive layer and the pressure-sensitive adhesive adheres to the back surface of the chip, thereby reducing the pickup property. It was observed.

Further, as can be seen from Table 2-4, in Examples 2-11 to 2-15 in which the semiconductor wafer processing pressure-sensitive adhesive sheet having the structure shown in FIG. 2 was evaluated, the interface peeling was successfully performed between the pressure-sensitive adhesive layer and the adhesive layer. It was possible to pick up all the semiconductor chips out of 200 chips.
On the other hand, in Comparative Example 2-6 using a photopolymerization initiator having a large weight average molecular weight, interface peeling between the pressure-sensitive adhesive layer and the adhesive layer was not successful, and 100 semiconductors in 200 chips. Only the chip could be picked up.
Also in Comparative Example 2-7 using a compound having at least two photopolymerizable carbon-carbon double bonds in the molecule and having a weight average molecular weight of 11,500, as in Comparative Example 2-6, Of the chips, only 100 semiconductor chips could be picked up.

While this invention has been described in conjunction with its embodiments, we do not intend to limit our invention in any detail of the description unless otherwise specified and are contrary to the spirit and scope of the invention as set forth in the appended claims. I think it should be interpreted widely.

This application claims priority based on Japanese Patent Application No. 2010-84447 filed in Japan on March 31, 2010 and Japanese Patent Application No. 2010-84531 filed on March 31, 2010 in Japan. Which are hereby incorporated by reference herein as part of their description.

DESCRIPTION OF SYMBOLS 1 Base resin film 2 Adhesive layer 3

Adhesive layer

10, 20 Adhesive sheet for semiconductor wafer processing

Claims

A radiation-permeable base resin film, and a pressure-sensitive adhesive sheet for processing semiconductor wafers, wherein the pressure-sensitive adhesive layer is formed on the base resin film, wherein the pressure-sensitive adhesive layer is a repeating unit of (i-1) main chain. On the other hand, with respect to 100 parts by mass of a base resin mainly composed of an acrylic polymer (a) having a residue having a (meth) acrylic monomer part having a radiation-curable carbon-carbon double bond-containing group. ,
(Iii) Radiation containing 0.1 to 10 parts by mass of a photopolymerization initiator (b) having a weight average molecular weight of less than 1000, converted to polystyrene as a standard substance by gel permeation chromatography (hereinafter referred to as “GPC”) method A pressure-sensitive adhesive sheet for processing a semiconductor wafer, comprising a layer using a curable resin composition.
A radiation-transmitting base resin film and an adhesive sheet for processing a semiconductor wafer having an adhesive layer formed on the base resin film, the adhesive layer comprising (i-2) 100 mass of acrylic polymer Against the department
(Ii) 1 to 300 parts by weight of a compound (c) having at least two photopolymerizable carbon-carbon double bonds in the molecule and having a weight average molecular weight of 10,000 or less,
(Iii) Radiation containing 0.1 to 10 parts by mass of a photopolymerization initiator (b) having a weight average molecular weight of less than 1000, converted to polystyrene as a standard substance by gel permeation chromatography (hereinafter referred to as “GPC”) method A pressure-sensitive adhesive sheet for processing a semiconductor wafer, comprising a layer using a curable resin composition.
The photopolymerization initiator (b) is 1-hydroxy-cyclohexylphenyl-ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-methyl-1- (4-methylthiophenyl) -2 -Morpholinopropan-1-one and an oligomer represented by the following general formula (1)

General formula (1)
(In the formula, R represents an alkyl group. N is an integer.)
The pressure-sensitive adhesive sheet for processing a semiconductor wafer according to claim 1 or 2, wherein the pressure-sensitive adhesive sheet is at least one selected from the group consisting of:
The pressure-sensitive adhesive sheet for processing a semiconductor wafer according to claim 3, wherein the degree of polymerization of the oligomer represented by the general formula (1) is n = 2 to 4.
The iodine value of the polymer (a) containing as a constituent unit an acrylic monomer having a radiation-polymerizable carbon-carbon double bond-containing group with respect to the repeating unit of the main chain is 1 to 50, The pressure-sensitive adhesive sheet for semiconductor wafer processing according to claim 1, 3 or 4.
6. A semiconductor wafer processing pressure-sensitive adhesive sheet, wherein an adhesive layer is further provided on the pressure-sensitive adhesive layer of the semiconductor wafer processing pressure-sensitive adhesive sheet according to any one of claims 1 to 5.