WO2016017789A1 - Adhesive sheet - Google Patents

Abstract

This adhesive sheet (1) comprises an adhesive agent layer (12) upon a substrate film (11), the adhesive agent layer (12) containing an energy-ray-curable polymer and a cross-linking agent, the energy-ray-curable polymer being obtained by copolymerizing a monomer that has a cyano group, and the cross-linking agent being a metal chelate compound.

Description

Adhesive sheet

The present invention relates to a pressure-sensitive adhesive sheet having solvent resistance and plating resistance.
This application claims priority based on Japanese Patent Application No. 2014-157580 filed in Japan on August 1, 2014, the contents of which are incorporated herein by reference.

After a circuit is formed on the front surface of the semiconductor wafer, the thickness is adjusted by grinding the back surface, and then the semiconductor wafer is fixed on a dicing sheet, and dicing is performed so that the semiconductor wafer is separated into a predetermined chip size. . The semiconductor chips separated into chips are picked up from the dicing sheet and transferred to the next process.

With the recent spread of IC cards, semiconductor chips are becoming thinner. Since a wafer thinned to obtain such a semiconductor chip is very easy to break, it may be damaged in a back surface grinding process, a subsequent processing process, a transfer process, or the like. Therefore, in these steps, the wafer is held on a hard support such as glass. After these steps are completed, the wafer is transferred from a hard support onto a dicing sheet (adhesive sheet), the outer periphery of the dicing sheet is fixed by a ring frame, and then the wafer is cut into circuits (dicing). ) To form a chip, and the chip is picked up from the dicing sheet. In this process, an adhesive or a decomposition product thereof may remain on the surface of the wafer after the hard support is peeled off. Therefore, in order to remove these adhesives and decomposition products thereof, the wafer fixed on the dicing sheet is washed with a polar organic solvent.

Further, a semiconductor wafer with a gold film for a power device is usually diced after a hard support is peeled off as described above, and the wafer fixed on the dicing sheet is immersed in a plating solution to form a gold film. Is done. As such an adhesive sheet having plating resistance assuming the use of a plating solution, for example, a sheet having a specific tensile elastic modulus and tear strength is disclosed (see, for example, Patent Document 1). .

JP 2005-68420 A

However, the conventional adhesive sheet including the one described in Patent Document 1 does not have sufficient resistance to solvent washing for removing the adhesive and its decomposition product as described above even though it has plating resistance. There is no problem.

This invention is made | formed in view of the said situation, and makes it a subject to provide the adhesive sheet which has solvent resistance and plating resistance.

In order to solve the above problems, the present invention comprises a pressure-sensitive adhesive layer on a base film, the pressure-sensitive adhesive layer contains an energy ray-curable polymer and a crosslinking agent, and the energy ray-curable polymer is The pressure-sensitive adhesive sheet is obtained by copolymerizing a monomer having a cyano group, and the crosslinking agent is a metal chelate compound.

In the pressure-sensitive adhesive sheet of the present invention, the cyano group-containing monomer is preferably acrylonitrile.
In the pressure-sensitive adhesive sheet of the present invention, the cross-linking agent is preferably an aluminum chelate compound or a titanium chelate compound.
In the pressure-sensitive adhesive sheet of the present invention, when the energy ray curable polymer is prepared by polymerization of the monomer, the ratio of the amount of the monomer having a cyano group to the total amount of the monomer is 0.2 to 30. The thing of the mass% is preferable.
In the pressure-sensitive adhesive sheet of the present invention, the cross-linking agent content of the pressure-sensitive adhesive layer is preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the energy ray curable polymer.
In the pressure-sensitive adhesive sheet of the present invention, the energy ray-curable polymer is preferably a (meth) acrylic acid ester copolymer having a hydroxyl group and having a polymerizable group in a side chain via a urethane bond.

According to the present invention, an adhesive sheet having solvent resistance and plating resistance is provided.

It is sectional drawing which shows typically the adhesive sheet which concerns on this invention.

<< Adhesive sheet >>
The pressure-sensitive adhesive sheet of the present invention comprises a pressure-sensitive adhesive layer on a base film, the pressure-sensitive adhesive layer contains an energy ray-curable polymer and a crosslinking agent, and the energy ray-curable polymer has a cyano group. The monomer is obtained by copolymerization, and the crosslinking agent is a metal chelate compound. As such an adhesive sheet, the adhesive sheet 1 by which the adhesive layer 12 is provided on the surface 11a of the base film 11 as shown in FIG. 1 can be illustrated, for example.
The pressure-sensitive adhesive sheet includes a pressure-sensitive adhesive layer containing an energy ray-curable polymer obtained by copolymerization of a monomer having a cyano group, and a crosslinking agent that is a metal chelate compound, so that solvent resistance and Both have plating resistance.

The pressure-sensitive adhesive sheet is suitable, for example, as a dicing sheet used in a series of steps in which a semiconductor wafer held on a hard support is transferred and diced into semiconductor chips. Since the pressure-sensitive adhesive sheet has solvent resistance, the adhesive layer and the semiconductor wafer are laminated even if the adhesive and the decomposition product adhered to the surface of the semiconductor wafer after transfer are washed with a polar organic solvent. The structure can be maintained stably. In addition, since the pressure-sensitive adhesive sheet has plating resistance, even if the metal film is formed by immersing the semiconductor wafer in the plating solution while being transferred, the pressure-sensitive adhesive layer and the laminated structure of the semiconductor wafer can be stabilized. Can be maintained. In the case of performing the above plating, the semiconductor wafer to which the adhesive sheet is affixed is sequentially immersed in, for example, the chemical solutions (1) to (9) below, but during this time, the adhesive layer does not change and the adhesive layer is not deteriorated. The laminated structure of the agent layer and the semiconductor wafer can be stably maintained.
(1) Degreasing solution (pH 10 to 12, room temperature to 50 ° C., including surfactant)
(2) Strong acid cleaning solution (sulfuric acid, nitric acid, pH 1 to 4, room temperature to 50 ° C)
(3) Conditioner solution (neutral at around pH 7, about room temperature, including surfactant)
(4) Zincate solution (first time) (pH 10-12, room temperature)
(5) Strong acid (sulfuric acid, nitric acid, pH 1-4, room temperature)
(6) Zincate solution (second time) (pH 10-12, room temperature)
(7) Nickel plating solution (pH 2-5, 70-90 ° C)
(8) Palladium plating solution (pH 2-5, 70-90 ° C)
(9) Gold plating solution (pH 2-5, 70-90 ° C)

The pressure-sensitive adhesive sheet is suitable for use in a step of contacting a polar organic solvent and a plating solution in a state where the semiconductor wafer is fixed as described above, for example, a step of manufacturing a semiconductor wafer with a gold film for a power device. It is also suitable for use in the manufacturing process or processing process of various electronic components having similar processes.

<Base film>
The material of the base film is preferably various resins, specifically, polyethylene (low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE, etc.)), polypropylene, polybutene. , Polybutadiene, polymethylpentene, polyvinyl chloride, vinyl chloride copolymer, polyethylene terephthalate, polybutylene terephthalate, polyimide, ethylene vinyl acetate copolymer, ionomer resin, polystyrene, polycarbonate, fluororesin, ethylene / (meth) acrylic acid Examples thereof include copolymers, ethylene / (meth) acrylic acid ester copolymers, water additives, modified products, cross-linked products or copolymers of any of these resins.
Among these, it is preferable that the material of the base film is polypropylene.

The base film may be composed of one layer (single layer) or may be composed of two or more layers. Moreover, when a base film consists of multiple layers, all the materials of each layer may be the same, all may be different, or only a part may be the same.

The thickness of the base film can be appropriately selected depending on the purpose, but is preferably 50 to 300 μm, and more preferably 60 to 100 μm.

In order to improve the adhesiveness with the adhesive layer provided on the base film, the concavo-convex treatment by sandblast treatment, solvent treatment, corona discharge treatment, electron beam irradiation treatment, plasma treatment, ozone / ultraviolet ray The surface may be subjected to oxidation treatment such as irradiation treatment, flame treatment, chromic acid treatment, or hot air treatment. Further, the base film may have a surface subjected to primer treatment.
Among these, as the base film, a film whose surface has been subjected to an electron beam irradiation treatment is particularly preferable from the viewpoint of suppressing generation of fragments of the base film due to blade friction during dicing.

<Adhesive layer>
The pressure-sensitive adhesive layer contains an energy ray-curable polymer and a crosslinking agent, and has a low adhesive strength after curing. If the adhesive layer is affixed to a semiconductor wafer, the pressure-sensitive adhesive layer is applied to a semiconductor chip obtained by dicing. High pick-up property.

The thickness of the pressure-sensitive adhesive layer can be appropriately selected depending on the purpose, but is preferably 1 to 100 μm, more preferably 1 to 60 μm, and particularly preferably 1 to 30 μm.

The pressure-sensitive adhesive layer is formed using a pressure-sensitive adhesive composition containing the target component. That is, the pressure-sensitive adhesive layer is formed using a pressure-sensitive adhesive composition containing an energy ray-curable polymer and a crosslinking agent, and the ratio of the content of non-volatile components of the pressure-sensitive adhesive composition is determined in the pressure-sensitive adhesive layer. Is the same.

[Energy ray curable polymer]
The energy ray-curable polymer in the pressure-sensitive adhesive layer is, for example, cured (polymerized) by irradiation with energy rays such as ultraviolet rays, and obtained by copolymerization of a monomer having a cyano group (—CN). It is. That is, the energy beam curable polymer has a structural unit derived from a monomer having the cyano group.

Examples of the monomer having a cyano group include those having a cyano group and a polymerizable unsaturated bond (—C═C— etc.), more specifically, acrylonitrile (CH ₂ ═CH—CN), Examples include methacrylonitrile (CH ₂ ═C (CH ₃ ) —CN), 2-vinylbenzonitrile (CH ₂ ═CH— (C ₆ H ₄ ) —CN), 3-vinylbenzonitrile, and 4-vinylbenzonitrile. .

Other than the structural unit derived from the monomer having the cyano group, the structural unit possessed by the energy beam curable polymer is not particularly limited and can be arbitrarily selected according to the purpose.

The energy ray curable polymer is preferably such that the ratio of the amount of the monomer having a cyano group to the total amount of the monomer is 0.2 to 30% by mass at the time of preparation by polymerization of the monomer. 0.4 to 20% by mass is more preferable, and 0.6 to 15% by mass is particularly preferable.

The energy ray curable polymer is preferably a (meth) acrylic acid ester copolymer, and has a hydroxyl group and a (meth) acrylic acid ester copolymer having a polymerizable group in a side chain via a urethane bond. More preferably, it is a polymer. The (meth) acrylic acid ester copolymer having such a hydroxyl group and a polymerizable group is crosslinked by the reaction of the hydroxyl group with the crosslinking agent. In addition, the (meth) acrylic acid ester copolymer having such a hydroxyl group and a polymerizable group has a polymerizable group in the side chain, for example, separately using a low molecular weight energy ray curable compound, The peelability from the adherend due to a decrease in the tackiness of the pressure-sensitive adhesive layer after the curing reaction is improved as compared with a case where the curing (polymerization) reaction is performed by irradiation with energy rays. With such an improvement in peelability, for example, easy pick-up performance for a semiconductor chip is improved. In addition, since there is no need to separately use a low molecular weight energy ray polymerizable compound, for example, transfer of the energy ray polymerizable compound from the pressure-sensitive adhesive layer containing such an energy ray polymerizable compound to a sticking object is performed. It is suppressed. In addition, the (meth) acrylic acid ester copolymer having such a hydroxyl group and a polymerizable group is remarkably suppressed from being eluted into the plating solution when the pressure-sensitive adhesive sheet described later comes into contact with the plating solution.
In this specification, “(meth) acrylic acid” is a concept including both “acrylic acid” and “methacrylic acid”.

((Meth) acrylic acid ester copolymer)
The (meth) acrylic acid ester copolymer is polymerized by using a composition comprising, for example, a (meth) acrylic acid ester, a hydroxyl group-containing monomer, and a monomer having the cyano group. Obtained by reacting the isocyanate group of the compound having an isocyanate group and a polymerizable group with the hydroxyl group of the polymer.

Preferred examples of the (meth) acrylic acid ester copolymer include a hydroxyl group-free (meth) acrylic acid ester, a hydroxyl group-containing (meth) acrylic acid ester, and a monomer having the cyano group as an essential monomer (monomer ) Can be exemplified by those obtained by reacting the hydroxyl group of an acrylic copolymer obtained by copolymerizing these monomers with the isocyanate group of a compound having an isocyanate group and a polymerizable group.

Examples of the hydroxyl group-free (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, (meth ) 2-ethylhexyl acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, (meth) acrylic Undecyl acid, dodecyl (meth) acrylate (lauryl (meth) acrylate), tridecyl (meth) acrylate, tetradecyl (meth) acrylate (myristyl (meth) acrylate), pentadecyl (meth) acrylate, (meth) Hexadecyl acrylate (palmethyl (meth) acrylate), (meth) acrylic acid The alkyl group constituting the alkyl ester, such as heptadecyl oxalate, octadecyl (meth) acrylate (stearyl (meth) acrylate), isooctadecyl (meth) acrylate (isostearyl (meth) acrylate), has 1 to (Meth) acrylic acid alkyl ester having 18 chain structure (hereinafter sometimes abbreviated as “(meth) acrylic acid C1-18 alkyl ester”); (meth) acrylic acid isobornyl, (meth) acrylic acid diester (Meth) acrylic acid cycloalkyl esters such as cyclopentanyl; (meth) acrylic acid aralkyl esters such as (meth) acrylic acid benzyl; (meth) acrylic acid cycloalkenyl esters such as (meth) acrylic acid dicyclopentenyl; (Meth) acrylic acid dicyclopentenyloxyethyl etc. Acrylate Cycloalkenyloxy alkyl esters; (meth) imide acrylate; (meth) containing a glycidyl group of glycidyl acrylate (meth) acrylic acid ester can be exemplified.

Among these, the hydroxyl group-free (meth) acrylic acid ester is a (meth) acrylic acid alkyl ester (hereinafter referred to as “(meth)”) in which the alkyl group constituting the alkyl ester has a chain structure having 8 to 18 carbon atoms. The acrylic copolymer is sometimes obtained by copolymerizing (meth) acrylic acid C8-18 alkyl ester as an essential monomer. preferable. By using an acrylic copolymer obtained by copolymerizing (meth) acrylic acid C8-18 alkyl ester, the pressure-sensitive adhesive layer is further excellent in solvent resistance.

Examples of the hydroxyl group-containing (meth) acrylic acid ester include hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and the like.

In addition to the above-mentioned essential monomers, the acrylic copolymer may contain any monomer such as (meth) acrylic acid; itaconic acid; non- (meth) acrylic monomers such as vinyl acetate, styrene, and N-methylolacrylamide. It may be copolymerized.

The acrylic copolymer is an acrylic copolymer obtained by copolymerizing the hydroxyl group-free (meth) acrylic acid C1-18 alkyl ester, hydroxyl group-containing (meth) acrylic ester, acrylonitrile and (meth) acrylic acid. A polymer (A ') is preferable.
The hydroxyl group-free (meth) acrylic acid C1-18 alkyl ester, hydroxyl group-containing (meth) acrylic acid ester and (meth) acrylic acid used for the preparation of the acrylic copolymer (A ′) are only one kind. However, two or more kinds may be used.

When the acrylic copolymer (A ′) is prepared by polymerization of the monomer, the ratio of the blended amount of the hydroxyl group-free (meth) acrylic acid C1-18 alkyl ester to the total blended amount of the monomer is 50 The content is preferably from 8 to 89.5% by mass, and more preferably from 60 to 84% by mass.
In the acrylic copolymer (A ′), the ratio of the amount of the hydroxyl group-containing (meth) acrylic acid ester to the total amount of the monomer is 10 to 30% by mass during the preparation by polymerization of the monomer. %, Preferably 15 to 25% by mass.
The acrylic copolymer (A ′) is preferably such that the ratio of the amount of acrylonitrile to the total amount of monomers is 0.3 to 15% by mass during the preparation by polymerization of the monomers. More preferred is 0.7 to 12% by mass.
In the acrylic copolymer (A ′), the ratio of the blended amount of (meth) acrylic acid to the total blended amount of the monomer is 0.2 to 5% by mass at the time of preparation by polymerization of the monomer. Some are preferable, and more preferably 0.3 to 3% by mass.

In the acrylic copolymer (A ′), the ratio of the blended amount of the hydroxyl group-free (meth) acrylic acid C1-18 alkyl ester to the total blended amount of the monomer is 50 to 50 at the time of preparation by polymerization of the monomer. 89.5% by mass, the proportion of the hydroxyl group-containing (meth) acrylic ester is 10 to 30% by mass, the proportion of acrylonitrile is 0.3 to 15% by mass, It is preferable that the ratio of the amount of (meth) acrylic acid is 0.2 to 5% by mass.
In the acrylic copolymer (A ′), the ratio of the amount of the hydroxyl group-free (meth) acrylic acid C1-18 alkyl ester with respect to the total amount of the monomer in the preparation by polymerization of the monomer is 60 to 84% by mass, the proportion of the hydroxyl group-containing (meth) acrylic acid ester is 15 to 25% by mass, the proportion of acrylonitrile is 0.7 to 12% by mass, It is more preferable that the ratio of the blending amount of acrylic acid is 0.3 to 3% by mass.

When the acrylic copolymer (A ′) is prepared by polymerization of the monomer, the hydroxyl group-free (meth) acrylic acid with respect to the total blending amount of the hydroxyl group-free (meth) acrylic acid C1-18 alkyl ester. The proportion of the C8-18 alkyl ester is preferably 40% by mass or more, more preferably 60% by mass or more, particularly preferably 80% by mass or more, and 100% by mass. There may be. By using such an acrylic copolymer (A ′) with a high proportion of the hydroxyl group-free (meth) acrylic acid C8-18 alkyl ester, the pressure-sensitive adhesive layer is more excellent in solvent resistance. It becomes.

Examples of the compound having an isocyanate group and a polymerizable group include isocyanate group-containing (meth) acrylic acid alkyl esters such as 2-methacryloyloxyethyl isocyanate.

In the reaction of the acrylic copolymer (A ′) with the compound having an isocyanate group and a polymerizable group for obtaining the (meth) acrylic acid ester copolymer, the copolymer has an isocyanate group and a polymerizable group. The amount of the compound used is preferably 40 to 100 mol% based on the structural unit derived from the hydroxyl group-containing (meth) acrylic acid ester in the acrylic copolymer (A ′). It is more preferable that the amount be ˜90 mol%. When the use amount of the compound having an isocyanate group and a polymerizable group is within such a range, the (meth) acrylic acid ester copolymer is brought into the plating solution at the time of contact with the plating solution of the adhesive sheet described later. Elution is further suppressed, and the characteristics of the pressure-sensitive adhesive layer are improved.

The compound having an isocyanate group and a polymerizable group used for the preparation of the (meth) acrylic acid ester copolymer may be only one kind or two or more kinds.

So far, the (meth) acrylic acid ester copolymer is obtained by reacting the hydroxyl group of the polymer having a hydroxyl group with the isocyanate group of a compound having an isocyanate group and a polymerizable group. explained. However, the (meth) acrylic acid ester copolymer in the present invention is not limited to this. For example, instead of the polymer having a hydroxyl group, a polymer having a hydroxyl group and a functional group other than a hydroxyl group is used, and an isocyanate is used. Instead of a compound having a group and a polymerizable group, a compound having a reactive group having a reactivity with the functional group and a compound having a polymerizable group is used to react the functional group with the reactive group. May be used. Here, the “polymerizable group” in the compound having a reactive group and a polymerizable group is the same as the “polymerizable group” in the compound having an isocyanate group and a polymerizable group.

Examples of the functional group other than the hydroxyl group include a carboxy group, an amino group in which one hydrogen atom may be substituted with a substituent such as an alkyl group, an epoxy group, and the like, and a monomer having these functional groups is copolymerized. By making it, the said polymer is obtained.
The reactive group may be selected according to the type of functional group other than the hydroxyl group, and is a hydroxyl group, a carboxy group, an amino group in which one hydrogen atom may be substituted with a substituent such as an alkyl group, an epoxy Examples include groups.

The polymer having a functional group other than the hydroxyl group, and the compound having the reactive group and the polymerizable group, used for the preparation of the (meth) acrylic acid ester copolymer, may be each one type or two types. That's all.

The energy ray curable polymer preferably has a weight average molecular weight of 100,000 to 2,000,000, more preferably 400,000 to 1,000,000. In addition, the weight average molecular weight demonstrated in this specification can be measured using the gel permeation chromatography method (GPC method: Gel Permeation Chromatography).

The energy ray-curable polymer contained in the pressure-sensitive adhesive composition may be one kind or two or more kinds.

The content of the energy ray-curable polymer of the pressure-sensitive adhesive composition is preferably 80% by mass or more, and 90% by mass or more with respect to the total amount of all the components other than the solvent in the pressure-sensitive adhesive composition. It is more preferable that Moreover, it is preferable that content of the energy-beam curable polymer of the said adhesive composition is 99 mass% or less with respect to the total amount of all the containing components other than the solvent in an adhesive composition, and 97. More preferably, it is 5 mass% or less. That is, the content of the energy ray-curable polymer in the pressure-sensitive adhesive composition is preferably in the range of 80 to 99% by mass with respect to the total amount of all the components other than the solvent in the pressure-sensitive adhesive composition. The range of 90 to 97.5% by mass is more preferable.

[Crosslinking agent]
The crosslinking agent is a metal chelate compound. In the present specification, “crosslinking agent” means a crosslinking agent which is this metal chelate compound unless otherwise specified.
Examples of the crosslinking agent include those in which a ligand which is an organic group is coordinated to a metal atom or a metal ion.
The cross-linking agent (metal chelate compound) is preferably an aluminum chelate compound in which the metal species is aluminum, a titanium chelate compound in which the metal species is titanium, or a zirconium chelate compound in which the metal species is zirconium. More preferably, it is a chelate compound.

Examples of the aluminum chelate compound include aluminum acetylacetonate (trisacetylacetonatoaluminum), aluminum trisethylacetoacetate, aluminum ethylacetoacetate diisopropylate (diisopropoxyaluminum 3-ethoxycarbonyl-2-propen-2-yloxide) Etc. can be illustrated.
Examples of the titanium chelate compound include tetrakis (2,4-pentandionato) titanium.
Examples of the zirconium chelate compound include tetrakis (2,4-pentanedionato) zirconium.

The cross-linking agent contained in the pressure-sensitive adhesive composition may be only one type or two or more types.

The content of the crosslinking agent in the pressure-sensitive adhesive composition (pressure-sensitive adhesive layer) is preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the energy ray-curable polymer, More preferably, it is 3 to 7 parts by mass, and particularly preferably 0.4 to 5 parts by mass.

[Photopolymerization initiator]
The pressure-sensitive adhesive composition preferably further contains a photopolymerization initiator in addition to the energy beam curable polymer and the crosslinking agent.
The photopolymerization initiator may be a known one, specifically, 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-α, α′-dimethylacetophenone, Α-ketol compounds such as 2-methyl-2-hydroxypropiophenone and 1-hydroxycyclohexyl phenyl ketone; methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl Acetophenone compounds such as -1- [4- (methylthio) -phenyl] -2-morpholinopropane-1; benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether and anisoin methyl ether; ketals such as benzyldimethyl ketal Compounds; 2-naphtha Aromatic sulfonyl chloride compounds such as sulfonyl chloride; photoactive oxime compounds such as 1-phenone-1,1-propanedione-2- (o-ethoxycarbonyl) oxime; benzophenone, benzoylbenzoic acid, 3,3 ′ -Benzophenone compounds such as dimethyl-4-methoxybenzophenone; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone Thioxanthone compounds such as 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone; camphorquinone; halogenated ketone; acyl phosphinoxide; acyl phosphonate; oligo [2-hydroxy-2-methyl -1- (4- (1-methyl) Vinyl) phenyl) propanone] and the like.
Among these, the photopolymerization initiator preferably has a molecular weight of 400 or more, and more preferably has a molecular weight of 600 or more. Such a photopolymerization initiator having a large molecular weight is remarkably suppressed from elution into the plating solution when the pressure-sensitive adhesive sheet comes into contact with the plating solution described later. As a result, the curing (polymerization) of the energy beam curable polymer by irradiation with energy rays proceeds well, and the peelability from the adherend due to the decrease in the tackiness of the pressure-sensitive adhesive layer after the curing reaction is improved, For example, easy pick-up for a semiconductor chip is improved.

The content of the photopolymerization initiator in the pressure-sensitive adhesive composition is preferably 0.05 to 20 parts by mass with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer. The effect by using a photoinitiator is fully acquired because the said content of a photoinitiator is more than the said lower limit. Moreover, generation | occurrence | production of the by-product from an excess photoinitiator is suppressed because the said content of a photoinitiator is below the said upper limit, and hardening of an adhesive layer advances more favorably.

(solvent)
The pressure-sensitive adhesive composition preferably further contains a solvent in addition to the energy beam curable polymer and the crosslinking agent.
The solvent is not particularly limited, and preferred examples include hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, 2-propanol, isobutyl alcohol (2-methylpropan-1-ol), and 1-butanol; Examples include esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; amides (compounds having an amide bond) such as dimethylformamide and N-methylpyrrolidone.
As for the solvent which the said adhesive composition contains, only 1 type may be sufficient and 2 or more types may be sufficient.

The content of the solvent in the pressure-sensitive adhesive composition is preferably 20 to 85% by mass and more preferably 30 to 65% by mass with respect to the total amount of the pressure-sensitive adhesive composition.

(Other ingredients)
The pressure-sensitive adhesive composition contains, in addition to the energy beam curable polymer, the crosslinking agent, the photopolymerization initiator, and the solvent, other components not corresponding to these within a range not impairing the effects of the present invention. Also good.
The said other component which the said adhesive composition contains may be only 1 type, and 2 or more types may be sufficient as it.

The other components may be known ones and can be arbitrarily selected according to the purpose, and are not particularly limited, but preferred are dyes, pigments, deterioration inhibitors, antistatic agents, flame retardants, silicone compounds, chains. Various additives such as a transfer agent can be exemplified.

As said other component, you may use crosslinking agents other than the said crosslinking agent (metal chelate compound) (henceforth abbreviated as "other crosslinking agent").
The other crosslinking agent is not particularly limited and may be a known one, but preferred are an isocyanate crosslinking agent (organic polyvalent isocyanate compound), an epoxy crosslinking agent (organic polyvalent epoxy compound), and an imine crosslinking. Examples thereof include organic agents (organic polyvalent imine compounds).

The isocyanate-based crosslinking agent is not particularly limited as long as it is a crosslinking agent having an isocyanate group (—N═C═O). Preferred examples include 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, trimethylolpropane, etc. Compounds obtained by adding an isocyanate, lysine diisocyanate and the like.

Examples of the epoxy crosslinking agent include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, 1,3-bis (N, N-diglycidylaminomethyl) toluene, N, N, N ′, N′-tetraglycidyl- Examples thereof include 4,4-diaminodiphenylmethane.

Examples of the imine crosslinking agent include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri- Examples thereof include β-aziridinylpropionate, N, N′-toluene-2,4-bis (1-aziridinecarboxyamide) triethylenemelamine and the like.

The content of the other crosslinking agent in the pressure-sensitive adhesive composition is preferably 0.1 parts by mass or less with respect to 1 part by mass of the crosslinking agent (metal chelate compound), 0.05 It is more preferable that the amount is not more than part by mass.

The content of the other components other than the other crosslinking agent in the pressure-sensitive adhesive composition can be arbitrarily adjusted according to the purpose.

The pressure-sensitive adhesive composition can be obtained by blending the energy ray-curable polymer, the crosslinking agent, and other components as necessary.
The order of addition at the time of blending each component is not particularly limited, and two or more components may be added simultaneously.
The method of mixing each component at the time of mixing is not particularly limited, and a known method such as a method of mixing by rotating a stirrer or a stirring blade; a method of mixing using a mixer; a method of mixing by applying ultrasonic waves May be selected as appropriate.
The temperature and time at the time of addition and mixing of each component are not particularly limited as long as each compounding component is not deteriorated, and may be appropriately adjusted. However, the temperature is preferably 15 to 30 ° C.
When using a solvent, it may be used by mixing the solvent with any compounding component other than the solvent and diluting the compounding component in advance, or diluting any compounding component other than the solvent in advance. You may use it by mixing a solvent with these compounding ingredients, without preparing.

In the pressure-sensitive adhesive sheet of this embodiment, the elastic modulus of the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition before irradiation with ultraviolet rays is preferably 0.02 to 0.12 MPa.
The gel fraction of the pressure-sensitive adhesive layer before ultraviolet irradiation, which can be measured by a method described in detail later, is preferably in the range of 5.6 to 20.1 (%).
Furthermore, the pressure-sensitive adhesive sheet of this embodiment was immersed in each solution of a nickel plating solution, warm water, an alkaline aqueous solution, and a sulfuric acid solution, which can be measured by a method described in detail later, in a state of being attached to a silicon wafer. Thereafter, the peel force change rate when the adhesive sheet is peeled from the silicon wafer is preferably −5% or more.

<< Method for producing adhesive sheet >>
The pressure-sensitive adhesive sheet of the present invention can be produced by forming a pressure-sensitive adhesive layer on the base film using the pressure-sensitive adhesive composition.

The pressure-sensitive adhesive layer can be formed by applying a pressure-sensitive adhesive composition to the surface of the base film, removing the solvent, and drying. In the pressure-sensitive adhesive sheet 1 illustrated in FIG. 1, a pressure-sensitive adhesive layer 12 is formed on the surface 11 a of the base film 11. At this time, you may bridge | crosslink by heating the apply | coated adhesive composition as needed. The heating conditions can be, for example, 100 to 130 ° C. and 0.5 to 5 minutes, but are not limited thereto. In addition, the pressure-sensitive adhesive layer can be formed by applying a pressure-sensitive adhesive composition to the surface of the release layer of the release material and drying it to attach the pressure-sensitive adhesive layer to the surface of the substrate film and removing the release material. . The conditions for forming the pressure-sensitive adhesive layer on the surface of the release layer of the release material can be the same as the conditions for forming the pressure-sensitive adhesive layer on the surface of the substrate film.

Application of the pressure-sensitive adhesive composition to the surface of the base film or the release layer of the release material may be carried out by a known method. Air knife coater, blade coater, bar coater, gravure coater, roll coater, roll knife coater, curtain Examples of the method include using various coaters such as a coater, a die coater, a knife coater, a screen coater, a Meyer bar coater, and a kiss coater.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples.

[Example 1]
<Manufacture of adhesive sheet>
(Manufacture of adhesive composition)
Energy ray curable polymer (weight average molecular weight 600000) (100 parts by mass), photopolymerization initiator (“ESACURE KIP 150” manufactured by DKSH, oligo [2-hydroxy-2-methyl-1- (4- (1- Methylvinyl) phenyl) propanone]) (3 parts by mass) and a crosslinking agent (“MA-5” manufactured by Soken Chemical Co., Ltd., aluminum chelate compound) (0.6 parts by mass) in methyl ethyl ketone (77 parts by mass) at 23 ° C. To obtain a pressure-sensitive adhesive composition.
The energy ray curable polymer is composed of lauryl acrylate (hereinafter abbreviated as “LA”) (68 parts by mass), methyl methacrylate (hereinafter abbreviated as “MMA”) (10 parts by mass), acrylic acid. -2-Hydroxyethyl (hereinafter abbreviated as “HEA”) (20 parts by mass), acrylonitrile (hereinafter abbreviated as “AN”) (1 part by mass) and acrylic acid (hereinafter abbreviated as “AA”) Acrylic copolymer (A′-1) (100 parts by mass) obtained by copolymerizing (1 part by mass) and 2-methacryloyloxyethyl isocyanate (hereinafter abbreviated as “MOI”) (21. (Meth) acrylic acid ester copolymer obtained by reacting 4 parts by mass with an amount of 80 mol% of the structural unit derived from HEA in the acrylic copolymer (A′-1). It is a polymer. The amount of each component is shown in Table 1 below. In Table 1 below, the notation “-” in the column of the blending component means that the component is not blended. The same applies to Tables 2 and 3 below.

(Manufacture of adhesive sheet)
The adhesive composition obtained above is applied to the release surface of a release film ("SP-PET 381031" manufactured by Lintec Corporation) and heated and dried at 120 ° C for 1 minute to form an adhesive layer having a thickness of 10 µm. did. Next, an adhesive sheet was obtained by laminating a 80 μm-thick polypropylene film on the surface of the adhesive layer.

<Evaluation of adhesive sheet>
(Plating resistance)
A pressure-sensitive adhesive sheet was affixed to the mirror-polished surface of a silicon wafer (diameter 6 inches, thickness 150 μm) whose one side was mirror-polished via the pressure-sensitive adhesive layer. The pasting conditions at this time were a temperature of 23 ° C., a pasting pressure of 0.3 MPa, and a pasting speed of 5 mm / second. Subsequently, the outer peripheral part of this sticky adhesive sheet was stuck on a resin ring frame (RF) under the same conditions to obtain a laminate.
Next, the obtained laminate was immersed in a nickel plating solution (“Epitus NPR-18” manufactured by Uemura Kogyo Co., Ltd.) at 80 ° C. for 20 minutes, 40 minutes, and 60 minutes. The infiltration of the liquid and the generation of bubbles were confirmed by visually observing the appearance. The results are shown in Tables 1 to 3 below.

(Adhesion change rate)
An adhesive sheet was attached to the mirror polished surface of the silicon wafer by the same method as in the case of the above-described evaluation of plating resistance.
Next, this silicon wafer (hereinafter abbreviated as “silicon wafer with adhesive sheet”) to which an adhesive sheet was attached was placed in (i) a nickel plating solution (“Epitus NPR-18” manufactured by Uemura Kogyo Co., Ltd.) at 80 ° C. at 60 ° C. (Ii) 60 minutes at 80 ° C. in warm water, (iii) 30 minutes at 50 ° C. in alkaline aqueous solution (degreasing solution “MCL-16” manufactured by Uemura Kogyo Co., Ltd.), and (iv) 60 minutes at 80 ° C. in sulfuric acid solution The sample was immersed in each liquid under any one of conditions.
Next, of the silicon wafer with the pressure-sensitive adhesive sheet after immersion, the attached pressure-sensitive adhesive sheet was peeled off from the silicon wafer under the conditions of a peeling angle of 180 ° and a peeling speed of 300 mm / min for an area of 25 mm × 25 cm in size. The peeling force was measured and used as the adhesive strength of the adhesive sheet. And also about the silicon wafer with an adhesive sheet before immersion, the adhesive force of the adhesive sheet was measured beforehand on the same conditions, and the adhesive force change rate of the adhesive sheet was computed from the following (1) formula. The results are shown in Tables 1 to 3 below. In Tables 1 to 3 below, the rate of change in adhesive strength for each liquid was defined as “no problem” when it was −5% or more, and “problem” when it was less than −5%.
Adhesive strength change rate (%) = (Adhesive strength of adhesive sheet after being immersed in liquid / Adhesive strength of adhesive sheet before being immersed in liquid) × 100-100 (1)

(Solvent resistance)
A pressure-sensitive adhesive sheet was affixed to the mirror-polished surface of a silicon wafer (diameter 8 inches, thickness 50 μm) whose one side was mirror-polished via the pressure-sensitive adhesive layer. The pasting conditions at this time were a temperature of 23 ° C., a pasting pressure of 0.3 MPa, and a pasting speed of 5 mm / second. Subsequently, the outer peripheral part of this sticky adhesive sheet was stuck on a resin ring frame (RF) under the same conditions to obtain a laminate.
Then, the obtained laminate was added to (v) propylene glycol-1-monomethyl ether-2-acetate (hereinafter abbreviated as “PGMEA”) at 50 ° C. for 5 minutes, or (vi) N-methylpyrrolidone ( Hereinafter, it was abbreviated as “NMP”) and immersed in each liquid under any condition of 60 minutes at room temperature.
Next, liquid appearance between the wafer and the pressure-sensitive adhesive sheet, peeling of the pressure-sensitive adhesive sheet from the wafer, peeling of the pressure-sensitive adhesive layer from the base material on the pressure-sensitive adhesive sheet, and the like were confirmed by visually observing the appearance. . The results are shown in Tables 1 to 3 below.

(Overall plating resistance and solvent resistance)
○ When there was no abnormality in all three items (plating resistance, solvent resistance, adhesive force change rate) (all passed), there was an abnormality in one item (one item failed) ) In the case of 2) or more, and x in the case of abnormality in 2 or more items (2 or more items failed), respectively. The results are shown in Tables 1 to 3 below.

(Dicing property)
The adhesive sheet was evaluated for the following “water intrusion / chip skip”, “chipping property”, “expanding property” and “pickup property”. These results are shown in Tables 1 to 3 below. The evaluation results shown in Tables 1 to 3 below describe “no problem” if there are no problems in all four items, and describe the contents if there is a problem in any of the items. is doing.

Water intrusion / chip jump: The pressure-sensitive adhesive sheet was stuck on the mirror-polished surface of a silicon wafer (diameter 6 inches, thickness 150 μm) with one side mirror-polished via the pressure-sensitive adhesive layer. The pasting conditions at this time were a temperature of 23 ° C., a pasting pressure of 0.3 MPa, and a pasting speed of 5 mm / second.
Next, this structure in which an adhesive sheet was attached to a silicon wafer was immersed in the chemical solutions (1) to (3) below in this order. During the immersion, cleaning with pure water was performed for 1 minute or more between the steps. The immersion in these chemicals is selected assuming the step of plating the structure.
(1) 10 minutes in degreasing solution (pH 10-12, room temperature to 50 ° C., including surfactant) (2) 40 minutes in strong acid cleaning solution (sulfuric acid, nitric acid, pH 1-4, room temperature to 50 ° C.) ) Nickel plating solution (pH 2-5, 70-90 ° C.) for 40 minutes Then, the silicon wafer was diced into a size of 2 mm × 2 mm to obtain chips. The case where the square chip after dicing peeled off from the adhesive sheet was regarded as “problem”. Evaluation was performed on the total number of chips.

Chipping property: In the same manner as in the case of “water intrusion / chip skipping”, the structure in which the adhesive sheet was stuck on the silicon wafer was sequentially immersed in the chemical solutions (1) to (3).
Next, the silicon wafer is diced to a size of 8 mm × 8 mm to form chips, and “no problem” is obtained when the number of chips with chipping (chips, etc.) of 30 μm or more inside from the dicing line is zero. In the case of one or more, “problem” was determined. Evaluation was performed on 5 vertical lines and 5 horizontal lines.

Expandability: First, the silicon wafer was diced into a size of 8 mm × 8 mm to obtain a chip by the same method as in the evaluation of the above chipping property. After that, the structure with the adhesive sheet attached to the tip is fixed to an expanding device ("SE-100" manufactured by JCM), and when the ring frame is pulled down by 10mm or 20mm, the adhesive sheet attached to the tip is attached. Accordingly, the case where the number of the adhesive sheets in which the base film was torn was 0 was “no problem”, and the case where it was 1 or more was “problem”.

Pick-up property: A structure in which an adhesive sheet is adhered to a silicon wafer is sequentially immersed in the chemical solutions (1) to (3) in the same manner as in the case of “water intrusion / chip skipping” and “chipping property”. .
Next, the silicon wafer was diced into a size of 10 mm × 10 mm to obtain a chip. Then, using a UV irradiation device (“RAD-2000m / 12” manufactured by Lintec Corporation), UV irradiation was performed under the conditions of an illuminance of 200 mW / cm ² and an amount of light of 200 mJ / cm ² , 5 mm expanding was performed, and 4 pins were raised. Went. At this time, the case where there was no adhesive residue on the chip and there was no chip crack was defined as “no problem”, and the case where there was at least one of adhesive residue and chip crack was defined as “problem”.

(Elastic modulus of the adhesive layer before UV irradiation)
A release sheet (“SPET382120” manufactured by Lintec Corporation) in which a silicone release agent layer (thickness: 0.1 μm) is formed on one main surface of a polyethylene terephthalate base film (thickness: 38 μm) is prepared. did. Then, the pressure-sensitive adhesive composition obtained above is applied onto the surface of the release agent layer of the release sheet with a knife coater so that the final pressure-sensitive adhesive layer has a thickness of 40 μm. A film was formed. The obtained coating film is allowed to elapse for 1 minute together with the release sheet in an environment of 100 ° C., whereby the coating film is dried to form an adhesive layer, and a laminate having the adhesive layer on the base film is obtained. Several sheets were produced.
Then, after peeling the base film using these laminates, the pressure-sensitive adhesive layer was bonded until the total thickness became 1 mm, and the resulting pressure-sensitive adhesive layer laminate was 10 mm in diameter. A sample for measuring viscoelasticity was obtained by punching into a circular shape.
Next, using a viscoelasticity measuring device (“ARES” manufactured by TA Instruments Inc.), the sample obtained above was strained at a frequency of 1 Hz, and the storage elastic modulus at −50 to 150 ° C. was measured. The value of the storage elastic modulus at 23 ° C. was defined as the elastic modulus of the pressure-sensitive adhesive layer before ultraviolet irradiation. The results are shown in Tables 1 to 3 below. In Tables 1 to 3 below, the elastic modulus of the pressure-sensitive adhesive layer before ultraviolet irradiation was “no problem” when 0.02 to 0.12 MPa, and “problem” otherwise.

(Gel fraction before UV irradiation of adhesive layer)
The pressure-sensitive adhesive layer was formed by the same method as in the case of the measurement of the elastic modulus before ultraviolet irradiation except that the thickness was changed to 20 μm instead of 40 μm.
Next, the pressure-sensitive adhesive layer was cut into a size of 50 mm × 100 mm, the obtained pressure-sensitive adhesive layer was wrapped with a nylon mesh (mesh size 200) of 100 mm × 150 mm, and the mass of the pressure-sensitive adhesive layer alone was weighed with a precision balance. . The mass at this time is M1. Next, the pressure-sensitive adhesive layer wrapped with the above nylon mesh was immersed in ethyl acetate (100 mL) at 25 ° C. for 24 hours, then taken out, dried at 120 ° C. for 1 hour, and further 23 ° C. and relative humidity 50 The humidity was adjusted by allowing to stand for 1 hour under the condition of%. Next, the mass of only the pressure-sensitive adhesive layer was weighed with a precision balance. The mass at this time is M2. And the gel fraction before the ultraviolet irradiation of an adhesive layer was computed by the following (2) formula. The results are shown in Tables 1 to 3 below.
Gel fraction (%) = (M2 / M1) × 100 (2)

<Manufacture and evaluation of adhesive sheet>
[Example 2]
As shown in Table 1 below, instead of the acrylic copolymer (A′-1), 2-ethylhexyl acrylate (hereinafter abbreviated as “2-EHA”) (68 parts by mass), MMA (10 (Parts by mass), HEA (20 parts by mass), AN (1 part by mass) and AA (1 part by mass) are used except that an acrylic copolymer (A′-2) obtained by copolymerization is used. A pressure-sensitive adhesive sheet was produced and evaluated in the same manner as in Example 1. The weight average molecular weight of the energy ray-curable polymer obtained using the acrylic copolymer (A′-2) was 600000. The results are shown in Table 1 below.

[Example 3]
As shown in Table 1 below, instead of the acrylic copolymer (A′-1), isooctyl acrylate (hereinafter abbreviated as “iOA”) (68 parts by mass), MMA (10 parts by mass), HEA (20 parts by mass), same as Example 1 except that an acrylic copolymer (A′-3) obtained by copolymerizing AN (1 part by mass) and AA (1 part by mass) was used. The adhesive sheet was manufactured and evaluated by the method. The weight average molecular weight of the energy ray-curable polymer obtained using the acrylic copolymer (A′-3) was 600000. The results are shown in Table 1 below.

[Example 4]
As shown in Table 1 below, instead of the acrylic copolymer (A′-1), isostearyl acrylate (hereinafter abbreviated as “iStA”) (69 parts by mass), MMA (10 parts by mass), Example 1 except that an acrylic copolymer (A′-4) obtained by copolymerizing HEA (20 parts by mass), AN (1 part by mass) and AA (1 part by mass) was used. An adhesive sheet was produced and evaluated in the same manner. The weight average molecular weight of the energy ray-curable polymer obtained using the acrylic copolymer (A′-4) was 600000. The results are shown in Table 1 below.

[Example 5]
As shown in Table 1 below, instead of the acrylic copolymer (A′-1), butyl acrylate (hereinafter abbreviated as “BA”) (68 parts by mass), MMA (10 parts by mass), HEA (20 parts by mass) Same as Example 1 except that an acrylic copolymer (A′-5) obtained by copolymerizing AN (1 part by mass) and AA (1 part by mass) was used. The adhesive sheet was manufactured and evaluated by the method. The weight average molecular weight of the energy ray-curable polymer obtained using the acrylic copolymer (A′-5) was 600000. The results are shown in Table 1 below. In the evaluation of the pressure-sensitive adhesive sheet of Example 5, the “dicing property” was performed using a pressure-sensitive adhesive sheet that was not immersed in the above chemical solution, and “water penetration / chip skipping”, “chipping property”. There was no problem in all the items of “expanding property” and “pickup property”.

[Example 6]
As shown in Table 1 below, instead of the acrylic copolymer (A′-1), LA (64 parts by mass), MMA (10 parts by mass), HEA (20 parts by mass), AN (5 parts by mass) In addition, a pressure-sensitive adhesive sheet was produced and evaluated in the same manner as in Example 1 except that an acrylic copolymer (A′-6) obtained by copolymerizing AA (1 part by mass) was used. The weight average molecular weight of the energy ray-curable polymer obtained using the acrylic copolymer (A′-6) was 600000. The results are shown in Table 1 below.

[Example 7]
As shown in Table 1 below, instead of the acrylic copolymer (A′-1), LA (58 parts by mass), MMA (10 parts by mass), HEA (20 parts by mass), AN (10 parts by mass) In addition, a pressure-sensitive adhesive sheet was produced and evaluated in the same manner as in Example 1 except that an acrylic copolymer (A′-7) obtained by copolymerizing AA (1 part by mass) was used. The weight average molecular weight of the energy ray-curable polymer obtained using the acrylic copolymer (A′-7) was 600000. The results are shown in Table 1 below.

[Example 8]
As shown in Table 2 below, instead of the acrylic copolymer (A′-1), LA (78 parts by mass), HEA (20 parts by mass), AN (1 part by mass), and AA (1 part by mass) A pressure-sensitive adhesive sheet was produced and evaluated in the same manner as in Example 1 except that an acrylic copolymer (A′-8) obtained by copolymerizing the above was used. The weight average molecular weight of the energy ray-curable polymer obtained using the acrylic copolymer (A′-8) was 600000. The results are shown in Table 2 below.

[Example 9]
As shown in Table 2 below, the titanium chelate compound “TC-401” (Matsumoto Fine Chemical Co., Ltd.) was used instead of the aluminum chelate compound “MA-5” (0.6 parts by mass) as a cross-linking agent during the production of the pressure-sensitive adhesive composition. A pressure-sensitive adhesive sheet was produced and evaluated in the same manner as in Example 1 except that manufactured titanium tetraacetylacetonate (0.8 parts by mass) was used. The results are shown in Table 2 below.

[Example 10]
As shown in Table 2 below, the embodiment was carried out except that the amount of the crosslinking agent (aluminum chelate compound “MA-5”) at the time of producing the pressure-sensitive adhesive composition was changed to 1 part by mass instead of 0.6 part by mass. A pressure-sensitive adhesive sheet was produced and evaluated in the same manner as in Example 1. The results are shown in Table 2 below.

[Example 11]
As shown in Table 2 below, the procedure was carried out except that the amount of the crosslinking agent (aluminum chelate compound “MA-5”) at the time of producing the pressure-sensitive adhesive composition was changed to 3 parts by mass instead of 0.6 parts by mass. A pressure-sensitive adhesive sheet was produced and evaluated in the same manner as in Example 1. The results are shown in Table 2 below.

[Example 12]
As shown in Table 2 below, in addition to the aluminum chelate compound “MA-5” (0.6 parts by mass), a tolylene diisocyanate trimer adduct of trimethylolpropane is used as a cross-linking agent during the production of the pressure-sensitive adhesive composition. (Hereinafter abbreviated as “TDI-TMP”) “BHS-8515” (manufactured by Toyo Ink Manufacturing Co., Ltd.) (0.01 parts by mass) was used to produce an adhesive sheet in the same manner as in Example 1. evaluated. The results are shown in Table 2 below.

[Reference Example 1]
As shown in Table 2 below, TDI-TMP “BHS-8515” (0.1%) in addition to the aluminum chelate compound “MA-5” (0.6 parts by mass) is used as a cross-linking agent in the production of the pressure-sensitive adhesive composition. A pressure-sensitive adhesive sheet was produced and evaluated in the same manner as in Example 1 except that (part by mass) was used. The results are shown in Table 2 below.

[Reference Example 2]
As shown in Table 2 below, in addition to the aluminum chelate compound “MA-5” (0.6 parts by mass), TDI-TMP “BHS-8515” (1 part by mass) is used as a cross-linking agent in the production of the pressure-sensitive adhesive composition. The adhesive sheet was produced and evaluated in the same manner as in Example 1 except that the above was used. The results are shown in Table 2 below.

[Comparative Example 1]
As shown in Table 3 below, instead of the acrylic copolymer (A′-1), LA (69 parts by mass), MMA (10 parts by mass), HEA (20 parts by mass) and AA (1 part by mass) An aluminum chelate compound “MA-5” (0.6 parts by mass) is used as a cross-linking agent in the production of a pressure-sensitive adhesive composition, using an acrylic copolymer (AR′-1) obtained by copolymerizing Instead of this, an adhesive sheet was produced and evaluated in the same manner as in Example 1 except that TDI-TMP “BHS-8515” (0.5 part by mass) was used. The weight average molecular weight of the energy ray-curable polymer obtained using the acrylic copolymer (AR′-1) was 600000. The results are shown in Table 3 below.

[Comparative Example 2]
As shown in Table 3 below, the acrylic copolymer (AR′-1) is used in place of the acrylic copolymer (A′-1), and further, as a cross-linking agent during the production of the pressure-sensitive adhesive composition. In the same manner as in Example 1, except that TDI-TMP “BHS-8515” (1 part by mass) was used instead of the aluminum chelate compound “MA-5” (0.6 part by mass). Manufactured and evaluated. The results are shown in Table 3 below.

[Comparative Example 3]
As shown in Table 3 below, instead of the aluminum chelate compound “MA-5” (0.6 parts by mass), TDI-TMP “BHS-8515” (0.5 A pressure-sensitive adhesive sheet was produced and evaluated in the same manner as in Example 1 except that (part by mass) was used. The results are shown in Table 3 below.

[Comparative Example 4]
As shown in Table 3 below, the epoxy compound “TC-5” (Taisei Pharmaceutical Co., Ltd.) was used instead of the aluminum chelate compound “MA-5” (0.6 parts by mass) as a cross-linking agent during the production of the pressure-sensitive adhesive composition. The pressure-sensitive adhesive sheet was produced and evaluated in the same manner as in Example 1 except that (manufactured) (0.5 part by mass) was used. The results are shown in Table 3 below.

[Comparative Example 5]
As shown in Table 3 below, a pressure-sensitive adhesive sheet was produced and evaluated in the same manner as in Example 1 except that no crosslinking agent was used during the production of the pressure-sensitive adhesive composition. The results are shown in Table 3 below.

[Comparative Example 6]
As shown in Table 3 below, adhesion was performed in the same manner as in Example 1 except that the acrylic copolymer (AR′-1) was used instead of the acrylic copolymer (A′-1). Sheets were manufactured and evaluated. The results are shown in Table 3 below.

[Comparative Example 7]
As shown in Table 3 below, instead of the acrylic copolymer (A′-1), it is obtained by copolymerizing LA (79 parts by mass), HEA (20 parts by mass) and AA (1 part by mass). A pressure-sensitive adhesive sheet was produced and evaluated in the same manner as in Example 1 except that the acrylic copolymer (AR′-2) was used. The weight average molecular weight of the energy ray-curable polymer obtained using the acrylic copolymer (AR′-2) was 600000. The results are shown in Table 3 below.

As is apparent from the results shown in the above tables, the pressure-sensitive adhesive sheets of Examples 1 to 4 and 6 to 12 have excellent resistance to resistance without impairing dicing properties because the pressure-sensitive adhesive layer has a composition in a specific range. It had solvent resistance, plating resistance, and adhesive force change rate. The pressure-sensitive adhesive sheet of Example 5 also had excellent plating resistance and adhesive force change rate because the pressure-sensitive adhesive layer had a composition in a specific range. In the pressure-sensitive adhesive sheet of Reference Example 1, the pressure-sensitive adhesive layer contained TDI-TMP that was not a metal chelate compound in addition to the metal chelate compound as a crosslinking agent, and the content (blending amount) of TDI-TMP was too large. Thus, even when immersed in any of nickel plating solution, warm water, alkaline aqueous solution and sulfuric acid solution, the adhesive force change rate was inferior. The pressure-sensitive adhesive sheet of Reference Example 2 has a higher content of TDI-TMP in the pressure-sensitive adhesive layer than the pressure-sensitive adhesive sheet of Reference Example 1, but as a result, the generation of bubbles is observed and the plating resistance is also improved. It was inferior, and the adhesive force change rate was further inferior.
In addition, the elasticity modulus and gel fraction before ultraviolet irradiation of an adhesive layer were favorable in any Example.

On the other hand, the pressure-sensitive adhesive sheet of Comparative Example 1 uses an acrylic copolymer (AR′-1) in which a monomer having a cyano group is not copolymerized, and uses a layer other than a metal chelate compound as a crosslinking agent. The generation of bubbles was observed and the plating resistance was inferior. Moreover, even when the pressure-sensitive adhesive sheet of Comparative Example 1 was immersed in any of nickel plating solution, warm water, alkaline aqueous solution and sulfuric acid solution, the adhesive force change rate was inferior. Furthermore, in the pressure-sensitive adhesive sheet of Comparative Example 1, water intrusion was recognized during dicing, and the dicing property was inferior.
The pressure-sensitive adhesive sheet of Comparative Example 2 is obtained by further increasing the content (blending amount) of the cross-linking agent in the pressure-sensitive adhesive layer as compared with the pressure-sensitive adhesive sheet of Comparative Example 1. The plating resistance was further inferior and the rate of change in adhesive force was further inferior, making it impossible to measure.

The pressure-sensitive adhesive sheet of Comparative Example 3 is provided with a pressure-sensitive adhesive layer using TDI-TMP that is not a metal chelate compound as a cross-linking agent, regardless of whether it is immersed in a nickel plating solution, warm water, an alkaline aqueous solution, or a sulfuric acid solution. The adhesive force change rate was inferior.
Similar to the pressure-sensitive adhesive sheet of Comparative Example 4, the pressure-sensitive adhesive sheet of Comparative Example 4 is provided with a pressure-sensitive adhesive layer using an epoxy compound that is not a metal chelate compound as a crosslinking agent. The rate of change in adhesive strength when immersed was inferior.

The pressure-sensitive adhesive sheet of Comparative Example 5 was provided with a pressure-sensitive adhesive layer that did not use a cross-linking agent. Adhesive residue was observed on the chip at the time of pick-up, and the dicing property was inferior, making it unsuitable for dicing.
The pressure-sensitive adhesive sheet of Comparative Example 6 is provided with a pressure-sensitive adhesive layer using an acrylic copolymer (AR′-1) in which a monomer having a cyano group is not copolymerized. The rate of change in adhesive strength was poor.
The pressure-sensitive adhesive sheet of Comparative Example 7 is also provided with a pressure-sensitive adhesive layer using an acrylic copolymer (AR′-2) in which a monomer having a cyano group is not copolymerized. Similarly, the adhesive force change rate when immersed in an alkaline aqueous solution was inferior.

As described above, the pressure-sensitive adhesive sheets of Comparative Examples 1 to 7 could not improve the solvent resistance, the plating resistance, and the adhesive force change rate without impairing the dicing property.

The present invention can be used for manufacturing or processing electronic parts such as semiconductor chips.

DESCRIPTION OF SYMBOLS 1 ... Adhesive sheet, 11 ... Base film, 11a ... Surface of base film, 12 ... Adhesive layer

Claims (6)

1. A pressure-sensitive adhesive layer is provided on the base film,
   The pressure-sensitive adhesive layer contains an energy ray-curable polymer and a crosslinking agent,
   The energy ray curable polymer is obtained by copolymerization of a monomer having a cyano group,
   The pressure-sensitive adhesive sheet, wherein the crosslinking agent is a metal chelate compound.
2. The pressure-sensitive adhesive sheet according to claim 1, wherein the monomer having a cyano group is acrylonitrile.
3. The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the crosslinking agent is an aluminum chelate compound or a titanium chelate compound.
4. When the energy ray curable polymer is prepared by polymerization of the monomer, the ratio of the amount of the monomer having a cyano group to the total amount of the monomer is 0.2 to 30% by mass. The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein:
5. The content of the crosslinking agent in the pressure-sensitive adhesive layer is 0.2 to 10 parts by mass with respect to 100 parts by mass of the energy ray curable polymer. The pressure-sensitive adhesive sheet according to any one of the above.
6. 6. The energy ray-curable polymer is a (meth) acrylic acid ester copolymer having a hydroxyl group and having a polymerizable group in a side chain via a urethane bond. The pressure-sensitive adhesive sheet according to any one of the above.

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