JP2022059761A - Sheet for workpiece processing - Google Patents

Abstract

To provide a sheet for workpiece processing that is less likely to contaminate an adherend at removal after active energy ray-irradiation and can also exhibit excellent antistatic properties.SOLUTION: A sheet for workpiece processing has a substrate, and an adhesive layer laminated on one side of the substrate. The adhesive layer is formed from an adhesive composition, wherein the adhesive composition contains a polymer having a quaternary ammonium salt and an active energy ray-curable group, an active energy ray-curable adhesive component (excluding the polymer), and an ionic liquid.SELECTED DRAWING: None

Description

The present invention relates to a work processing sheet used for processing a work such as a semiconductor wafer.

Semiconductor wafers such as silicon and gallium arsenide and various packages are manufactured in a large diameter state, cut (diced) into chips, peeled (picked up), and then moved to the next step, the mounting process. At this time, a work such as a semiconductor wafer is back grinded, diced, washed, and laminated on an adhesive sheet (hereinafter, may be referred to as a “work processing sheet”) provided with a base material and an adhesive layer. Processing such as drying, expanding, picking up, and mounting is performed.

When a sheet provided with an adhesive layer exhibiting active energy ray curability is used as the work processing sheet, the adhesive force is reduced by irradiation with active energy rays, and the work processing sheet is separated from the processed work. It can be easily peeled off. Here, when the work sheet is peeled off from the machined work, static electricity called peel charge may be generated between the work sheet and the machined work. The generation of such static electricity causes the circuit formed on the machine to be destroyed when the processed work is, for example, a semiconductor chip. In order to prevent this, it is known that the work processing sheet has antistatic properties by containing a low molecular weight quaternary ammonium salt compound in the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer. There is.

However, when a low molecular weight quaternary ammonium salt compound is used as an antistatic agent, the compound bleeds out from the pressure-sensitive adhesive layer, and the residue (particles) of the pressure-sensitive adhesive contaminates the surface of the processed work. There was a problem that it would end up.

On the other hand, as an antistatic pressure-sensitive adhesive, an anti-static pressure-sensitive adhesive for optical members containing a (meth) acrylic copolymer having a quaternary ammonium salt as a pressure-sensitive adhesive has been proposed (Patent Documents). 1). Such a pressure-sensitive adhesive is obtained by introducing a quaternary ammonium salt into a (meth) acrylic copolymer to obtain a high molecular weight.

Japanese Unexamined Patent Publication No. 2011-12195

However, in recent years, the miniaturization and high density of electronic devices have progressed, and the miniaturization of workpieces that are parts of such electronic devices and the miniaturization of structures such as circuits formed on the workpieces have also progressed dramatically. I'm out. In handling such a work, the antistatic property of the conventional pressure-sensitive adhesive sheet as in Patent Document 1 has become insufficient.

Further, the pressure-sensitive adhesive disclosed in Patent Document 1 is used for a pressure-sensitive adhesive sheet attached to an optical member such as a polarizing plate, and is not premised on peeling by irradiation with active energy rays. Therefore, the required physical properties are completely different from the work processing sheet whose adhesive strength changes significantly before and after irradiation with active energy rays.

The present invention has been made in view of such an actual situation, and is used for workpiece processing capable of exhibiting excellent antistatic properties while suppressing contamination of the adherend at the time of peeling after irradiation with active energy rays. The purpose is to provide a sheet.

In order to achieve the above object, first, the present invention is a work processing sheet including a base material and a pressure-sensitive adhesive layer laminated on one side of the base material, wherein the pressure-sensitive adhesive layer is 4. It is characterized by being formed from a pressure-sensitive adhesive composition containing a polymer having a quaternary ammonium salt and an active energy ray-curable group, an active energy ray-curable pressure-sensitive adhesive component (excluding the polymer), and an ionic liquid. (Invention 1).

In the work processing sheet according to the above invention (Invention 1), the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer contains an ionic liquid together with a quaternary ammonium salt and a polymer having an active energy ray-curable group. As a result, it is possible to exhibit excellent antistatic properties while suppressing contamination of the adherend at the time of peeling after irradiation with active energy rays.

In the above invention (Invention 1), the cationic component constituting the ionic liquid preferably has at least one of a hydroxy group and a vinyl group (Invention 2).

（上記式（１）～（４）のそれぞれにおいて、Ｒ_１～Ｒ_４は、それぞれ独立に、水素原子または炭素数１～２０のアルキル基であり、ｎは、それぞれ独立に、０～２０の整数である。）
で示される少なくとも１種の構造を有するものであることが好ましい（発明３）。 In the above inventions (Inventions 1 and 2), the cation component constituting the ionic liquid is represented by the following formulas (1) to (4).

(In each of the above formulas (1) to (4), R ₁ to R ₄ are independently hydrogen atoms or alkyl groups having 1 to 20 carbon atoms, and n is independently 0 to 20. It is an integer.)
It is preferable that it has at least one structure shown in (Invention 3).

In the above inventions (Inventions 1 to 3), the content of the ionic liquid in the pressure-sensitive adhesive composition is 1 part by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the active energy ray-curable pressure-sensitive adhesive component. It is preferable that there is (Invention 4).

In the above inventions (Inventions 1 to 4), the weight average molecular weight of the polymer is preferably 500 or more and 200,000 or less (Invention 5).

In the above inventions (Inventions 1 to 5), the content of the polymer in the pressure-sensitive adhesive composition is 1 part by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the active energy ray-curable pressure-sensitive adhesive component. It is preferable (Invention 6).

In the above inventions (Inventions 1 to 6), the active energy ray-curable adhesive component preferably contains an acrylic polymer having an active energy ray-curable group introduced into the side chain (Invention 7).

In the above inventions (Inventions 1 to 7), it is preferable that the pressure-sensitive adhesive composition does not contain an alkali metal salt (Invention 8).

In the above inventions (Inventions 1 to 8), a dicing sheet is preferable (Invention 9).

The work processing sheet according to the present invention can exhibit excellent antistatic properties while suppressing contamination of the adherend at the time of peeling after irradiation with active energy rays.

Hereinafter, embodiments of the present invention will be described.
The work processing sheet according to the present embodiment includes a base material and an adhesive layer laminated on one side of the base material. The pressure-sensitive adhesive layer is made of a pressure-sensitive adhesive composition containing a quaternary ammonium salt, a polymer having an active energy ray-curable group, an active energy ray-curable pressure-sensitive adhesive component (excluding the above polymer), and an ionic liquid. It was formed.

Since the above-mentioned quaternary ammonium salt and the polymer and ionic liquid having an active energy ray-curable group can exhibit excellent conductivity in the pressure-sensitive adhesive layer, the work processing sheet according to the present embodiment is very difficult. It has excellent antistatic properties.

Further, the quaternary ammonium salt and the polymer having an active energy ray-curable group are chemically bonded to each other and between the polymer and the active energy ray-curable adhesive component by irradiation with active energy rays. As a result of forming a three-dimensional structure, it is well retained in the pressure-sensitive adhesive layer. On the other hand, the ionic liquid also has high compatibility with other components in the pressure-sensitive adhesive layer, so that it is well retained in the pressure-sensitive adhesive layer. As a result, in the work processing sheet according to the present embodiment, it is possible to suppress the bleed-out of the components in the pressure-sensitive adhesive layer and the adhesion of the pressure-sensitive adhesive residue (particles) on the surface of the adherend.

1. 1. Structure of Work Sheet (1) Base Material The base material in the present embodiment is not particularly limited as long as it exhibits a desired function when the work processing sheet is used. In particular, the base material is preferably a resin film whose main material is a resin-based material. Specific examples thereof include polyolefin films such as polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film, norbornene resin film; polyethylene terephthalate film, polybutylene terephthalate film, and polyethylene. Polyester film such as naphthalate; ethylene-vinyl acetate copolymer film; ethylene- (meth) acrylic acid copolymer film, ethylene- (meth) methyl acrylate copolymer film, other ethylene- (meth) acrylic Ethylene-based copolymer films such as acid ester copolymer films; polyvinyl chloride-based films such as polyvinyl chloride films and vinyl chloride copolymer films; (meth) acrylic acid ester copolymer films; polyurethane films; polyimide films; Polystyrene film; polycarbonate film; fluororesin film and the like can be mentioned. Further, modified films such as these crosslinked films and ionomer films are also used. Further, the base material may be a laminated film in which a plurality of the above-mentioned films are laminated. In this laminated film, the materials constituting each layer may be the same type or different types. Among the above, it is preferable to use a polyvinyl chloride film, and it is particularly preferable to use a polyvinyl chloride film. In addition, "(meth) acrylic acid" in this specification means both acrylic acid and methacrylic acid. The same applies to other similar terms. Further, the term "polymer" in the present specification also includes the concept of "copolymer".

The substrate may contain various additives such as flame retardants, plasticizers, antistatic agents, lubricants, antioxidants, colorants, infrared absorbers, ultraviolet absorbers, ion scavengers and the like. The content of these additives is not particularly limited, but is preferably in the range in which the base material exhibits a desired function.

The surface on which the pressure-sensitive adhesive layer of the base material is laminated may be subjected to surface treatment such as primer treatment, corona treatment, and plasma treatment in order to improve the adhesion to the pressure-sensitive adhesive layer.

The thickness of the base material can be appropriately set depending on the method in which the work processing sheet is used, but is preferably 200 μm or less, and particularly preferably 150 μm or less. The thickness of the base material is preferably 10 μm or more, and particularly preferably 25 μm or more.

(2) Adhesive Layer The adhesive layer in the present embodiment is a pressure-sensitive adhesive composition containing a quaternary ammonium salt, a polymer having an active energy ray-curable group, an active energy ray-curable pressure-sensitive adhesive component, and an ionic liquid. It is formed from. In the present specification, the active energy ray-curable adhesive component does not contain a quaternary ammonium salt and a polymer having an active energy ray-curable group.

The pressure-sensitive adhesive composition in the present embodiment preferably does not contain an alkali metal salt. As a result, metal contamination can be effectively suppressed in the apparatus for handling the work to be the adherend and the work processing sheet according to the present embodiment.

(2-1) Active energy ray-curable adhesive component (A)
The active energy ray-curable adhesive component (A) contains an acrylic polymer (A1) and an active energy ray-curable compound (A2) having no active energy ray-curable property, or has an energy ray in the side chain. It preferably contains an acrylic polymer (A3) into which a curable group has been introduced. The active energy ray-curable adhesive component (A) contains an acrylic polymer (A3) having an energy ray-curable group introduced into the side chain and an active energy ray-curable compound (A2). It is also good.

From the viewpoint of effectively suppressing contamination of the adherend, the active energy ray-curable adhesive component (A) contains an acrylic polymer (A3) in which an energy ray-curable group is introduced into the side chain. It is preferable that it is one.

The active energy ray-curable adhesive component (A) in the present embodiment preferably does not contain an emulsion-based polymer from the viewpoint of easily suppressing contamination of the adherend.

(2-1-1) Acrylic polymer (A1) having no active energy ray curability
When the pressure-sensitive adhesive composition in the present embodiment contains an acrylic polymer (A1) having no active energy ray curability, the acrylic polymer (A1) may be contained as it is in the pressure-sensitive adhesive composition. Often, at least a part thereof may be contained as a cross-linked product by performing a cross-linking reaction with the cross-linking agent (C) described later.

As the acrylic polymer (A1), a conventionally known acrylic polymer can be used. The acrylic polymer (A1) may be a homopolymer formed from one type of acrylic monomer, a copolymer formed from a plurality of types of acrylic monomers, or 1 It may be a copolymer formed from one kind or a plurality of kinds of acrylic monomers and a monomer other than the acrylic monomers. The specific type of the compound to be the acrylic monomer is not particularly limited, and examples thereof include (meth) acrylic acid, (meth) acrylic acid ester, and derivatives thereof (acrylonitrile, itaconic acid, etc.). Further specific examples of the (meth) acrylic acid ester include a chain skeleton such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. (Meta) acrylate; Cyclic skeleton such as cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, imide acrylate, etc. (Meta) acrylates; (meth) acrylates having hydroxy groups such as 2-hydroxyethyl (meth) acrylates and 2-hydroxypropyl (meth) acrylates; glycidyl (meth) acrylates and N-methylaminoethyl (meth) acrylates. Examples thereof include (meth) acrylates having a reactive functional group other than the hydroxy group. Further, examples of the monomer other than the acrylic monomer include olefins such as ethylene and norbornene, vinyl acetate, and styrene. When the acrylic monomer is an alkyl (meth) acrylate, the number of carbon atoms of the alkyl group is preferably in the range of 1 to 18.

When the pressure-sensitive adhesive composition in the present embodiment contains a cross-linking agent (C) described later, the acrylic polymer (A1) preferably has a reactive functional group that reacts with the cross-linking agent (C). .. The type of the reactive functional group is not particularly limited, and may be appropriately determined based on the type of the cross-linking agent (C) and the like.

For example, when the cross-linking agent (C) is an epoxy compound, examples of the reactive functional group of the acrylic polymer (A1) include a carboxy group, an amino group and an amide group, and among them, an epoxy group. A highly reactive carboxy group is preferred. When the cross-linking agent (C) is a polyisocyanate compound, examples of the reactive functional group of the acrylic polymer (A1) include a hydroxy group, a carboxy group, an amino group and the like, and among them, an isocyanate group. A highly reactive hydroxy group is preferred.

The method for introducing a reactive functional group into the acrylic polymer (A1) is not particularly limited, and as an example, a monomer having a reactive functional group is used to form an acrylic polymer (A1) to form a reactive functional group. Examples thereof include a method in which a structural unit based on a monomer having the above is contained in the skeleton of a polymer. For example, when a carboxy group is introduced into the acrylic polymer (A1), the acrylic polymer (A1) may be formed by using a monomer having a carboxy group such as (meth) acrylic acid.

When the acrylic polymer (A1) has a reactive functional group, it is derived from a monomer having a reactive functional group in the total mass of the acrylic polymer (A1) from the viewpoint of keeping the degree of cross-linking in a good range. The mass ratio of the structural portion of the above is preferably 1% by mass or more, and particularly preferably 2% by mass or more. Further, from the same viewpoint, the above ratio is preferably 40% by mass or less, and particularly preferably 30% by mass or less.

The weight average molecular weight (Mw) of the acrylic polymer (A1) is preferably 10,000 or more, and particularly preferably 100,000 or more, from the viewpoint of film-forming property at the time of coating. Further, the weight average molecular weight (Mw) of the acrylic polymer (A1) is preferably 2 million or less, and particularly preferably 1.5 million or less, from the same viewpoint. The weight average molecular weight in the present specification is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method.

The glass transition temperature Tg of the acrylic polymer (A1) is preferably −70 ° C. or higher, and particularly preferably −60 ° C. or higher. The glass transition temperature Tg is preferably 30 ° C. or lower, and particularly preferably 20 ° C. or lower. The glass transition temperature can be calculated from the Fox equation.

(2-1-2) Active energy ray-curable compound (A2)
When the active energy ray-curable adhesive component (A) contains an acrylic polymer (A1) having no active energy ray curability, the active energy ray-curable adhesive compound (A2) is also contained. The active energy ray-curable compound (A2) is a compound having an active energy ray-curable group and polymerizing when irradiated with energy rays such as ultraviolet rays and electron beams.

The active energy ray-curable group contained in the active energy ray-curable compound (A2) is, for example, a group containing an active energy ray-curable carbon-carbon double bond, and specifically, a (meth) acryloyl group or vinyl. A group and the like can be exemplified.

The example of the active energy ray-curable compound (A2) is not particularly limited as long as it has the above-mentioned active energy ray-curable group, but from the viewpoint of versatility, a low molecular weight compound (monofunctional, polyfunctional monomer and It is preferably an oligomer). Specific examples of the low molecular weight active energy ray-curable compound (A2) include trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, pentaerythritol triacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate or 1 , 4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, dicyclopentadiene dimethoxydiacrylate, cyclic aliphatic skeleton-containing acrylate such as isobornyl acrylate, polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate oligomer, Examples thereof include acrylate compounds such as epoxy-modified acrylates, polyether acrylates, and itaconic acid oligomers.

The molecular weight of the active energy ray-curable compound (A2) is preferably 100 or more, and particularly preferably 300 or more. The molecular weight of the active energy ray-curable compound (A2) is preferably 30,000 or less, and particularly preferably 10,000 or less.

The ratio of the acrylic polymer (A1) to the active energy ray-curable compound (A2) is as follows: 10 parts by mass of the active energy ray-curable compound (A2) with respect to 100 parts by mass of the acrylic polymer (A1). It is preferable to use the above, and it is particularly preferable to use it in an amount of 30 parts by mass or more. Further, it is preferable to use the active energy ray-curable compound (A2) in an amount of 400 parts by mass or less, and particularly preferably 350 parts by mass or less, with respect to 100 parts by mass of the acrylic polymer (A1).

(2-1-3) Acrylic polymer (A3) in which an active energy ray-curable group is introduced into the side chain.
When the active energy ray-curable adhesive component (A) in the present embodiment contains an acrylic polymer (A3) in which an active energy ray-curable group is introduced into a side chain, the acrylic polymer (A3) may be used. It may be contained as it is in the pressure-sensitive adhesive composition, or at least a part thereof may be contained as a cross-linked product by performing a cross-linking reaction with a cross-linking agent (C) described later.

The main skeleton of the acrylic polymer (A3) in which the active energy ray-curable group is introduced into the side chain is not particularly limited, and the same as the above-mentioned acrylic polymer (A1) is exemplified.

The active energy ray-curable group introduced into the side chain of the acrylic polymer (A3) is, for example, a group containing an active energy ray-curable carbon-carbon double bond, specifically, a (meth) acryloyl group. Etc. can be exemplified. The active energy ray-curable group may be bonded to the acrylic polymer (A3) via an alkylene group, an alkyleneoxy group, a polyalkyleneoxy group or the like.

The acrylic polymer (A3) in which an active energy ray-curable group is introduced into the side chain is an acrylic polymer containing a functional group such as a hydroxy group, a carboxy group, an amino group, a substituted amino group or an epoxy group. And a substituent that reacts with the functional group and a curable group-containing compound having 1 to 5 active energy ray-curable carbon-carbon double bonds per molecule are reacted with each other. Such an acrylic polymer comprises a (meth) acrylic acid ester monomer or a derivative thereof having a functional group such as a hydroxy group, a carboxy group, an amino group, a substituted amino group, or an epoxy group, and a monomer constituting the above-mentioned component (A1). It is obtained by copolymerizing with. Examples of the curable group-containing compound include (meth) acryloyloxyethyl isocyanate, meta-isopropenyl-α, α-dimethylbenzyl isocyanate, (meth) acryloyl isocyanate, allyl isocyanate, and glycidyl (meth) acrylate; (meth). Acrylic acid and the like can be mentioned.

When the pressure-sensitive adhesive composition in the present embodiment contains a cross-linking agent (C) described later, the acrylic polymer (A3) having an active energy ray-curable group introduced into the side chain is a cross-linking agent. It is preferable to have a reactive functional group that reacts with (C). The type of the reactive functional group is not particularly limited, and the same as the above-mentioned acrylic polymer (A1) can be exemplified.

The weight average molecular weight (Mw) of the acrylic polymer (A3) in which the active energy ray-curable group is introduced into the side chain is preferably 100,000 or more, and particularly preferably 300,000 or more. The weight average molecular weight (Mw) is preferably 2 million or less, and particularly preferably 1.5 million or less.

The glass transition temperature (Tg) of the acrylic polymer (A3) is preferably −70 ° C. or higher, and particularly preferably −60 ° C. or higher. The glass transition temperature (Tg) is preferably 30 ° C. or lower, and particularly preferably 20 ° C. or lower. In the present specification, the glass transition temperature (Tg) of the acrylic polymer (A3) refers to that of the acrylic polymer before it is reacted with the curable group-containing compound.

(2-2) Polymer (B) having a quaternary ammonium salt and an active energy ray-curable group
The pressure-sensitive adhesive composition in the present embodiment is a polymer (B) having a quaternary ammonium salt and an active energy ray-curable group in addition to the above-mentioned active energy ray-curable pressure-sensitive adhesive component (A) (hereinafter, “energy ray-curable”). It contains an antistatic polymer (B) ”).

The active energy ray-curable antistatic polymer (B) exhibits antistatic properties by having a quaternary ammonium salt. The active energy ray-curable antistatic polymer (B) may have a quaternary ammonium salt in the main chain or the side chain, but it is preferable to have the quaternary ammonium salt in the side chain. The quaternary ammonium salt is composed of a quaternary ammonium cation and an anion for the quaternary ammonium cation, and is composed of a quaternary ammonium cation covalently bonded to the active energy ray-curable antistatic polymer (B) and an anion for the quaternary ammonium cation. It may be composed of an anion covalently bonded to the active energy ray-curable antistatic polymer (B) and a quaternary ammonium cation to the anion.

Here, the above-mentioned "quaternary ammonium cation" means an onium cation of nitrogen, and includes a heterocyclic onium ion such as imidazolium and pyridium. The quaternary ammonium cation includes an alkylammonium cation (“alkyl” here includes a hydrocarbon group having 1 to 30 carbon atoms, as well as those substituted with hydroxyalkyl and alkoxyalkyl); pyrrolidi. Complex monocyclic cations such as nium cations, pyrrolium cations, imidazolium cations, pyrazolium cations, pyridinium cations, piperidinium cations, piperazinium cations; indolium cations, benzimidazolium cations, carbazolium cations, ki Condensed heterocyclic cations such as norinium cations; and the like. All of them include those in which a hydrocarbon group having 1 to 30 carbon atoms (for example, 1 to 10 carbon atoms), a hydroxyalkyl group or an alkoxyalkyl group is bonded to a nitrogen atom and / or a ring.

Examples of the anion include an anion having a halogen atom and a derivative of an oxo acid such as a carboxylic acid, a sulfonic acid, and a phosphoric acid (for example, hydrogen sulfate, methanesulfonate, ethyl sulfate, dimethyl phosphate, 2- (2- (2-). Methoxyethoxy) ethylsulfate, dicyanamide, etc.) can be mentioned, but an anion having a halogen atom is preferable. Specifically, (FSO ₂ ) ₂ N- ⁽ bis {(fluoro) sulfonyl} imide anion), (CF ₃ SO ₂ ) ₂ N- ⁽ bis {(trifluoromethyl) sulfonyl} imide anion), (C ₂ ). F ₅ SO ₂ ) ₂ N- ⁽ bis {(pentafluoroethyl) sulfonyl} imide anion), CF ₃ SO ₂ -N-COCF _3- ^, R-SO ₂ -N ^- SO ₂ CF _3- (R is aliphatic) Group), ArSO ₂ -N ^- SO ₂ CF _3- (Ar is an aromatic group) and other anions having a nitrogen atom; Cn F _{2n + 1} CO _2- ⁽ _n is an integer of 1 to 4), (CF ₃ SO ₂ ). ) ₃ C- ^, C _n F _{2n + 1} SO _3- ⁽ n is an integer of 1 to 4), BF _4- ^, PF _6- ^{, and} the like, anions having a fluorine atom as a halogen atom are preferably exemplified. Among these, bis {(fluoro) sulfonyl} imide anion, bis {(trifluoromethyl) sulfonyl} imide anion, bis {(pentafluoroethyl) sulfonyl} imide anion, 2,2,2-trifluoro-N-{ (Trifluoromethyl) sulfonyl)} acetimide anions, tetrafluoroborate anions, and hexafluorophosphosphate anions are particularly preferred.

Further, the active energy ray-curable antistatic polymer (B) has an active energy ray-curable group in the side chain, so that when the pressure-sensitive adhesive layer is irradiated with the active energy ray, the active energy ray-curable charge is charged. The preventive polymers (B) or the active energy ray-curable antistatic polymer (B) react with each other or the above-mentioned active energy ray-curable adhesive component (A) to crosslink. Therefore, the bleed-out of the active energy ray-curable antistatic polymer (B) from the pressure-sensitive adhesive layer is suppressed, and the residue (particles) of the pressure-sensitive adhesive is less likely to be generated when the work processing sheet is peeled off. Contamination of the body can be suppressed.

The active energy ray-curable group is, for example, a group containing an active energy ray-curable carbon-carbon double bond. Specific examples thereof include (meth) acryloyl group and vinyl group, and among them, (meth) acryloyl group, particularly methacryloyl group is preferable.

The content of the active energy ray-curable group per unit mass of the active energy ray-curable antistatic polymer (B) is preferably 5 × 10 ^-5 mol / g or more, particularly 1 × 10 ^-4 mol / g. It is preferably g or more, and more preferably 3 × 10 ^-4 mol / g or more. The content is preferably 2 × 10 ^-3 mol / g or less, particularly preferably 1.5 × 10 ^-3 mol / g or less, and further preferably 1 × 10 ^-3 mol / g. The following is preferable. When the content of the active energy ray-curable group is 5 × 10 ^-5 mol / g or more, the active energy ray-curable antistatic polymers (B) can be exposed to each other by irradiation with the active energy ray, or the active energy ray-curable antistatic agent. The cross-linking between the polymer (B) and the active energy ray-curable adhesive component (A) becomes sufficient, and contamination of the adherend by the adhesive layer can be effectively suppressed. Further, since the content of the active energy ray-curable group is 2 × 10 ^-3 mol / g or less, the adhesive layer is not excessively cured when the pressure-sensitive adhesive layer is cured by the active energy ray, and is adhered after curing. Unintentional separation from the body is suppressed.

The active energy ray-curable antistatic polymer (B) in the present embodiment is, for example, reactive with a polymerizable monomer having a quaternary ammonium salt (hereinafter, may be referred to as “quaternary ammonium salt monomer (B1)”). After copolymerizing a polymerizable monomer having a functional group (hereinafter, may be referred to as “reactive functional group-containing monomer (B2)”) and another polymerizable monomer (B3), if desired, the above reactive functionality. Those obtained by reacting with a curable group-containing compound (B4) having a substituent and an active energy ray-curable group that react with the group are preferable, but the present invention is not limited thereto.

The quaternary ammonium salt monomer (B1) has a polymerizable group and a salt composed of a quaternary ammonium cation and an anion thereof, and preferably a quaternary ammonium cation having a polymerizable group and the like. Consists of a salt composed of anions for. Examples of the polymerizable group include a carbon-carbon unsaturated group such as a (meth) acryloyl group, a vinyl group and an allyl group, cyclic ethers having an epoxy group and an oxetane group, cyclic sulfides such as tetrahydrothiophene and an isocyanate group. Etc., among which (meth) acryloyl group and vinyl group are preferable.

Examples of the quaternary ammonium cation having a polymerizable group include trialkylaminoethyl (meth) acrylate ammonium cation, trialkylaminopropyl (meth) acrylamide ammonium cation, 1-alkyl-3-vinylimidazolium cation, and 4-. Vinyl-1-alkylpyridinium cation, 1- (4-vinylbenzyl) -3-alkylimidazolium cation, 1- (vinyloxyethyl) -3-alkylimidazolium cation, 1-vinyl imidazolium cation, 1-allyl imidazolium cation Lium cation, N-alkyl-N-allylammonium cation, 1-vinyl-3-alkylimidazolium cation, 1-glycidyl-3-alkyl-imidazolium cation, N-allyl-N-alkylpyrrolidinium cation, quaternary Examples thereof include diallyldialkylammonium cations (here, "alkyl" refers to a hydrocarbon group having 1 to 10 carbon atoms). Among these, trialkylaminoethyl (meth) acrylate ammonium cation (= [2- (methacryloyloxy) ethyl] trialkylammonium cation) is preferable.

The quaternary ammonium salt monomer (B1) may be a salt composed of the quaternary ammonium cation having a polymerizable group and the anion, for example, [2- (methacryloyloxy) ethyl] trimethylammonium bis. (Trifluoromethylsulfonyl) imide and the like can be mentioned. The quaternary ammonium salt monomer (B1) can be used alone or in combination of two or more.

In the active energy ray-curable antistatic polymer (B), the ratio of the mass of the structural portion derived from the quaternary ammonium salt monomer (B1) to the total mass of the polymer (B) is preferably 20% by mass or more. In particular, it is preferably 25% by mass or more, and more preferably 35% by mass or more. Further, the above ratio is preferably 80% by mass or less, particularly preferably 75% by mass or less, and further preferably 60% by mass or less. When the mass ratio of the structural portion derived from the quaternary ammonium salt monomer (B1) is 20% by mass or more, the active energy ray-curable antistatic polymer (B) exhibits sufficient antistatic properties. On the other hand, when the mass ratio of the structural portion derived from the quaternary ammonium salt monomer (B1) is 80% by mass or less, the mass ratio of the structural portion derived from another monomer can be controlled within a preferable range.

Examples of the reactive functional group-containing monomer (B2) include (meth) acrylic acid ester monomers having functional groups such as a carboxy group, a hydroxy group, an amino group, a substituted amino group and an epoxy group, in addition to the (meth) acrylic acid. Among them, (meth) acrylic acid is preferable.

In the active energy ray-curable antistatic polymer (B), the ratio of the mass of the structural portion derived from the reactive functional group-containing monomer (B2) to the total mass of the polymer (B) is 1% by mass or more. It is preferable, and it is particularly preferable that it is 3% by mass or more. The ratio is preferably 35% by mass or less, particularly preferably 20% by mass or less, and further preferably 10% by mass or less. Since the proportion of the mass of the structural portion derived from the reactive functional group-containing monomer (B2) is in the above range, the energy ray-curable antistatic polymer of the active energy ray-curable group based on the curable group-containing compound (B4). The introduction amount with respect to (B) can be controlled within a preferable range.

The active energy ray-curable antistatic polymer (B) preferably contains the above-mentioned other polymerizable monomer (B3), particularly an acrylic polymerizable monomer, as a monomer unit constituting the polymer (B). It is more preferable to contain it as an ingredient. As such other polymerizable monomer (B3), (meth) acrylic acid ester is preferably mentioned. The (meth) acrylic acid ester has a chain skeleton such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate (. Meta) acrylate; It has a cyclic skeleton such as cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, and imide acrylate. Meta) Acrylate and the like can be mentioned. When the (meth) acrylic acid ester is a (meth) acrylic acid alkyl ester, the number of carbon atoms of the alkyl group is preferably in the range of 1 to 18.

As the curable group-containing compound (B4), the same curable group-containing compound as that exemplified in the acrylic polymer (A3) can be exemplified. As the curable group-containing compound (B4), glycidyl (meth) acrylate, (meth) acryloyloxyethyl isocyanate and the like are preferable, and glycidyl (meth) acrylate is particularly preferable.

Here, it is preferable that the curable group-containing compound (B4) and the reactive functional group-containing monomer (B2) are reacted so that the molar equivalents are about the same.

The weight average molecular weight of the active energy ray-curable antistatic polymer (B) is preferably 500 or more, and particularly preferably 800 or more. The weight average molecular weight is preferably 200,000 or less, particularly preferably 100,000 or less, and further preferably 50,000 or less. When the weight average molecular weight of the active energy ray-curable antistatic polymer (B) is 500 or more, when the work processing sheet according to the present embodiment is attached to an adherend, the active energy ray-curable antistatic polymer (B) B) can effectively suppress bleeding out from the pressure-sensitive adhesive layer. Further, if the weight average molecular weight of the active energy ray-curable antistatic polymer (B) is 200,000 or less, there is no possibility of adversely affecting the adhesiveness of the pressure-sensitive adhesive layer. Specifically, the molecular chain of the ionic energy ray-curable antistatic polymer (B) tends to expand, but this is suppressed, and the adhesive layer does not become hard and exhibits good adhesiveness. The holding performance of the body is maintained.

The content of the active energy ray-curable antistatic polymer (B) in the pressure-sensitive adhesive composition of the present embodiment is 1 part by mass or more with respect to 100 parts by mass of the active energy ray-curable adhesive component (A). It is preferable, in particular, 5 parts by mass or more, and further preferably 10 parts by mass or more. The content is preferably 50 parts by mass or less, particularly preferably 35 parts by mass or less, and further 30 parts by mass with respect to 100 parts by mass of the active energy ray-curable adhesive component (A). The following is preferable. When the blending amount of the active energy ray-curable antistatic polymer (B) is 1 part by mass or more, sufficient antistatic property is imparted to the pressure-sensitive adhesive layer. Further, when the blending amount of the active energy ray-curable antistatic polymer (B) is 50 parts by mass or less, the cohesive force of the pressure-sensitive adhesive layer before irradiation with the active energy rays is maintained high, and the pressure-sensitive adhesive layer has preferable elasticity. Therefore, the influence of vibration during dicing is suppressed, and the occurrence of chipping (chip end chipping) is effectively suppressed. Further, when the blending amount of the active energy ray-curable antistatic polymer (B) is 50 parts by mass or less, it is possible to effectively suppress contamination of the adherend and deterioration of peelability after irradiation with active energy rays. Can be done.

(2-3) Ionic liquid (C)
The type of the ionic liquid (C) in the present embodiment is not particularly limited as long as it is a salt that exists as a liquid at room temperature (25 ° C., 1 atm). The melting point of the ionic liquid (C) is preferably 150 ° C. or lower, and particularly preferably 100 ° C. or lower. On the other hand, the lower limit of the melting point of the ionic liquid (C) is not particularly limited, and is, for example, −50 ° C. or higher.

Examples of the cationic component constituting the ionic liquid (C) in the present embodiment include pyridiniums such as pyridinium and alkylpyridinium; pyridiniums; pyrizoliums; pyrrolidiniums; piperidiniums; cyclic pyrrolidiniums; imidazoliums and dialkylimidazoles. Examples thereof include imidazolium type such as lithium; ammonium type of tetraalkylammonium type; phosphin type such as phosphonium, trialkylsulfonium, tetraalkylphosphonium and the like.

The cation component in this embodiment preferably has at least one of a hydroxy group and a vinyl group. When the cationic component has these groups, it becomes easy to exhibit antistatic properties and it becomes possible to more effectively suppress contamination of the adherend.

（上記式（１）～（４）のそれぞれにおいて、Ｒ_１～Ｒ_４は、それぞれ独立に、水素原子または炭素数１～２０のアルキル基であり、ｎは、それぞれ独立に、０～２０の整数である。）
で示される少なくとも１種の構造を有するものであることも好ましい。カチオン成分が上述した構造を有するものであることにより、形成される粘着剤層がより優れた帯電防止性を発揮し易いものとなる。 The cation component in this embodiment is represented by the following formulas (1) to (4).

(In each of the above formulas (1) to (4), R ₁ to R ₄ are independently hydrogen atoms or alkyl groups having 1 to 20 carbon atoms, and n is independently 0 to 20. It is an integer.)
It is also preferable that it has at least one structure shown by. Since the cation component has the above-mentioned structure, the formed pressure-sensitive adhesive layer tends to exhibit more excellent antistatic properties.

Examples of the cation component constituting the ionic liquid (C) in the present embodiment include Cl ⁻ , Br ⁻ , I ⁻ , AlCl _4- , Al ₂ Cl ₇ ⁻ , BF _4- ^, PF ₆ ⁻ , ^and ClO ₄ . ^- , NO _3- ^, CH ₃ COO- ^, CF ₃ COO- ^, CH ₃ SO _3- ^, CF ₃ SO _3- ^, (FSO ₂ ) ₂ N- ^, (CF ₃ SO ₂ ) ₂ N- ^, (CF ₃ SO) ₂ ) ₃ C- ^, AsF _6- ^, SbF _6- ^, NbF _6- ^, TaF _6- ^, F (HF) _n- , (CN) ₂ N-, C ₄ F ₉ SO _3- ^, (C ₂ F ₅ SO) ₂ ) ₂ N- ^, C ₃ F ₇ COO- ^, (CF ₃ SO ₂ ) (CF ₃ CO) N- ^and the like can be mentioned.

Specific examples of the above-mentioned ammonium-based cation component include trioctylmethylammonium = bistrifluoromethanesulfonylimide, trimethylpropylammonium = bistrifluoromethanesulfonylimide, and dimethylethyl [2- (2-methoxyethoxy) ethyl] ammonium = bistri. Fluoromethanesulfonylimide, diethylmethyl (2-methoxyethyl) ammonium = bistrifluoromethanesulfonylimide, diethylmethyl (2-methoxyethyl) ammonium = tetrafluorophosphate, dimethylethyl [2- (2-methoxyethoxy) ethyl] ammonium = Examples thereof include tetrafluorophosphate and diethylmethyl (2-methoxyethyl) ammonium = hexafluorophosphate.

Specific examples of the above-mentioned imidazolium-based cation component include 1-ethyl-3-methylimidazolium = bistrifluoromethanesulfonylimide, 1-ethyl-3-methylimidazolium = tetrafluoroborate, and 1-propyl-3-. Methylimidazolium = bistrifluoromethanesulfonylimide, 1-propyl-3-methylimidazolium = tetrafluoroborate, 1-butyl-3-methylimidazolium = bistrifluoromethanesulfonylimide, 1-butyl-3-methylimidazolium = Tetrafluoroborate, 1-pentyl-3-methylimidazolium = bistrifluoromethanesulfonylimide, 1-pentyl-3-methylimidazolium = tetrafluoroborate, 1-hexyl-3-methylimidazolium = bistrifluoromethanesulfonylimide, 1-Hexyl-3-methylimidazolium = tetrafluoroborate, 1,3-diethylimidazolium = bistrifluoromethanesulfonylimide, 1,3-diethylimidazolium = tetrafluorophosphate, 1-ethyl-2,3-dimethylimidazole Examples thereof include rium = bistrifluoromethanesulfonylimide, 1-ethyl-2,3-dimethylimidazolium = tetrafluoroborate and the like.

Specific examples of the above-mentioned pyridinium-based cation component include 1-butylpyridinium = bistrifluoromethanesulfoniumimide, 1-pentylpyridinium = bistrifluoromethanesulfoniumimide, 1-hexylpyridinium = bistrifluoromethanesulfoniumimide, and 1-butyl-. Examples thereof include 3-methylpyridinium = bistrifluoromethanesulfonylimide, 1-butyl-4-methylpyridinium = bistrifluoromethanesulfonylimide, 1-hexyl-4-methylpyridinium = bistrifluoromethanesulfonylimide and the like.

Specific examples of the above-mentioned pyrrolidinium-based cation component include 1-methyl-1-propylpyrrolidinium = bistrifluoromethanesulfoniumimide, 1-butyl-1-methylpyrrolidinium = bistrifluoromethanesulfoniumimide, 1-. Examples thereof include methyl-1-pentylpyrrolidinium = bistrifluoromethanesulfoniumimide, 1-hexyl-1-methylpyrrolidinium = bistrifluoromethanesulfoniumimide and the like.

Specific examples of the above-mentioned piperidinium-based cation component include 1-methyl-1-butylpiperidinium = bistrifluoromethanesulfoniumimide, 1-methyl-1-pentylpiperidinium = bistrifluoromethanesulfoniumimide, and 1-methyl. -1-Hexylpiperidinium = bistrifluoromethanesulfoniumimide and the like can be mentioned.

Specific examples of the above-mentioned phosphinic cation component include tributylmethylphosphonium = bistrifluoromethanesulfoniumimide, triethyloctylphosphonium = bistrifluoromethanesulfoniumimide, tripropyloctylphosphonium = bistrifluoromethanesulfoniumimide, and tributyloctylphosphonium = bistrifluoro. Examples thereof include methanesulfoniumimide.

Specific examples of commercially available ionic products include product names "IL-A1", "IL-A2", "IL-MA1", "IL-MA2", "IL-MA3", and "IL-MA3" manufactured by Koei Chemical Industry Co., Ltd. "IL-OH2" and "IL-OH9" can be mentioned.

The content of the ionic liquid (C) in the pressure-sensitive adhesive composition of the present embodiment is preferably 0.5 parts by mass or more with respect to 100 parts by mass of the active energy ray-curable pressure-sensitive adhesive component (A), and particularly 1 It is preferably 2 parts by mass or more, and more preferably 2 parts by mass or more. The content is preferably 100 parts by mass or less, particularly preferably 80 parts by mass or less, and further 60 parts by mass with respect to 100 parts by mass of the active energy ray-curable adhesive component (A). The following is preferable. When the blending amount of the ionic liquid (C) is 0.5 parts by mass or more, the pressure-sensitive adhesive layer is sufficiently imparted with antistatic properties. Further, when the blending amount of the ionic liquid (C) is 100 parts by mass or less, the cohesive force of the pressure-sensitive adhesive layer before irradiation with active energy rays is maintained high, and the pressure-sensitive adhesive layer has preferable elasticity. The influence of vibration is suppressed, and the occurrence of chipping (chip end chipping) is effectively suppressed.

(2-4) Crosslinking agent (D)
As described above, the pressure-sensitive adhesive composition in the present embodiment may contain a cross-linking agent (C) capable of reacting with the acrylic polymer (A1) or the acrylic polymer (A3). In this case, the pressure-sensitive adhesive layer in the present embodiment contains a cross-linked product obtained by a cross-linking reaction between the acrylic polymer (A1) or the acrylic polymer (A3) and the cross-linking agent (C).

Examples of the type of the cross-linking agent (C) include polyimine compounds such as epoxy compounds, polyisocyanate compounds, metal chelate compounds, and aziridine compounds, melamine resins, urea resins, dialdehydes, methylol polymers, and metal alkoxides. Examples include metal salts. Among these, an epoxy compound or a polyisocyanate compound is preferable because it is easy to control the crosslinking reaction.

Examples of the epoxy compound include 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane, N, N, N', N'-tetraglycidyl-m-xylylene diamine, and ethylene glycol diglycidyl ether. , 1,6-Hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidyl aniline, diglycidyl amine and the like.

The polyisocyanate compound is a compound having two or more isocyanate groups per molecule. Specifically, aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanates, alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanates, and the like, and their like. Examples thereof include a biuret form, an isocyanurate form, and an adduct form which is a reaction product with a low molecular weight active hydrogen-containing compound such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil.

The content of the cross-linking agent (C) in the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer is 100 parts by mass based on the total amount of the energy ray-curable adhesive component (A) and the energy ray-curable antistatic polymer (B). It is preferably 0.01 part by mass or more, and particularly preferably 0.1 part by mass or more. The content of the cross-linking agent (C) is preferably 50 parts by mass or less with respect to 100 parts by mass of the total amount of the energy ray-curable adhesive component (A) and the energy ray-curable antistatic polymer (B). In particular, it is preferably 10 parts by mass or less.

When the pressure-sensitive adhesive composition in the present embodiment contains a cross-linking agent (C), it is preferable to contain an appropriate cross-linking accelerator depending on the type of the cross-linking agent (C) and the like. For example, when the cross-linking agent (C) is a polyisocyanate compound, the pressure-sensitive adhesive composition preferably contains an organometallic compound-based cross-linking accelerator such as an organotin compound.

(2-5) Other Components In addition to the above components, the pressure-sensitive adhesive composition in the present embodiment contains various additives such as a photopolymerization initiator, coloring materials such as dyes and pigments, flame retardants, and fillers. May be.

Specific examples of the photopolymerization initiator include photoinitiators such as benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanosen compounds, thioxanthone compounds and peroxide compounds, and photosensitizers such as amines and quinones. 1-Hydroxycyclohexylphenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl diphenyl sulfide, tetramethylthium monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, β-chloranthraquinone. 2,4,6-trimethylbenzoyldiphenylphosphine oxide and the like are exemplified. When ultraviolet rays are used as the active energy rays, the irradiation time and irradiation amount can be reduced by adding a photopolymerization initiator.

(2-6) Thickness of Adhesive Layer The thickness of the adhesive layer in the present embodiment is preferably 2 μm or more, particularly preferably 3 μm or more, and further preferably 5 μm or more. The thickness of the pressure-sensitive adhesive layer is preferably 50 μm or less, particularly preferably 30 μm or less, and further preferably 20 μm or less. When the thickness of the pressure-sensitive adhesive layer is 2 μm or more, the desired pressure-sensitive adhesive force can be easily exerted. On the other hand, when the thickness of the pressure-sensitive adhesive layer is 20 μm or less, the amount of the pressure-sensitive adhesive adhesive generated when dicing the work can be suppressed to a small amount, which is caused by the pressure-sensitive adhesive adhered to the work or the like. It is unlikely that problems will occur.

(3) Peeling Sheet In the work processing sheet according to the present embodiment, the surface of the adhesive layer opposite to the base material (hereinafter, may be referred to as “adhesive surface”) is attached to the work until it is attached to the work. A release sheet may be laminated on the surface for the purpose of protecting the surface.

The structure of the release sheet is arbitrary, and examples thereof include a plastic film peeled with a release agent or the like. Specific examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. As the release agent, a silicone type, a fluorine type, a long chain alkyl type or the like can be used, and among these, a silicone type which can obtain stable performance at a low cost is preferable.

The thickness of the release sheet is not particularly limited, and may be, for example, 20 μm or more and 250 μm or less.

(4) Others In the work processing sheet according to the present embodiment, the adhesive layer may be laminated on the surface of the pressure-sensitive adhesive layer opposite to the base material. In this case, the work processing sheet according to the present embodiment can be used as a dicing / die bonding sheet. In the sheet, a work is attached to the surface of the adhesive layer opposite to the pressure-sensitive adhesive layer, and the adhesive layer is diced together with the work to obtain a chip in which individualized adhesive layers are laminated. be able to. The individualized adhesive layer makes it possible to easily fix the chip to the object on which the chip is mounted. As the material constituting the above-mentioned adhesive layer, a material containing a thermoplastic resin and a low molecular weight thermosetting adhesive component, a material containing a B stage (semi-curable) thermosetting adhesive component, and the like are used. It is preferable to use it.

Further, in the work processing sheet according to the present embodiment, a protective film forming layer may be laminated on the adhesive surface of the adhesive layer. In this case, the work processing sheet according to the present embodiment can be used as a protective film forming and dicing sheet. In such a sheet, a work is attached to the surface of the protective film forming layer opposite to the pressure-sensitive adhesive layer, and the protective film forming layer is diced together with the work, whereby the individualized protective film forming layer is laminated. You can get the chips that have been diced. As the work, it is preferable to use a work having a circuit formed on one surface, and in this case, a protective film forming layer is usually laminated on a surface opposite to the surface on which the circuit is formed. The individualized protective film forming layer can be cured at a predetermined timing to form a protective film having sufficient durability on the chip. The protective film forming layer is preferably made of an uncured curable adhesive.

2. 2. Physical Properties of Work Sheet (1) Surface resistivity In the work sheet according to the present embodiment, the surface resistivity of the pressure-sensitive adhesive layer before irradiation with ultraviolet rays is preferably 1 × 10 ¹³ Ω / □ or less. In particular, it is preferably 1 × 10 ¹² Ω / □ or less, and more preferably 2 × 10 ¹¹ Ω / □ or less. The lower limit of the surface resistivity of the pressure-sensitive adhesive layer before irradiation with ultraviolet rays is not particularly limited, and may be, for example, 1 × ¹⁰⁷ Ω / □ or more.

Further, in the work processing sheet according to the present embodiment, the surface resistivity of the pressure-sensitive adhesive layer after irradiation with ultraviolet rays is preferably 1 × 10 ¹³ Ω / □ or less, particularly 1 × 10 ¹² Ω / □ or less. It is preferable to have. The lower limit of the surface resistivity of the pressure-sensitive adhesive layer after irradiation with ultraviolet rays is not particularly limited, and may be, for example, 1 × ¹⁰⁷ Ω / □ or more.

The workpiece processing sheet according to the present embodiment can satisfactorily achieve the surface resistivity in the above-mentioned range. Thereby, when the work processing sheet according to the present embodiment is peeled from the adherend, it is possible to prevent the adherend from being destroyed by the peeling charge. The details of the method for measuring the surface resistivity before and after the above-mentioned ultraviolet irradiation are as described in the test examples described later.

(2) Adhesive Strength In the work processing sheet according to the present embodiment, the adhesive strength with respect to the silicon wafer before irradiation with active energy rays is preferably 2000 mN / 25 mm or more, and particularly preferably 3000 mN / 25 mm or more. Further, it is preferably 3500 mN / 25 mm or more. The adhesive strength is preferably 20000 mN / 25 mm or less, particularly preferably 15000 mN / 25 mm or less, and further preferably 10000 mN / 25 mm or less. When the adhesive force before irradiation with the active energy ray is within the above range, it becomes easy to reliably fix the work when processing the work.

Further, in the work processing sheet according to the present embodiment, the adhesive force to the silicon wafer after irradiation with active energy rays is preferably 500 mN / 25 mm or less, particularly preferably 300 mN / 25 mm or less, and further 200 mN. It is preferably / 25 mm or less. When the adhesive force after irradiation with the active energy ray is within the above range, the work can be easily peeled off from the work processing sheet at the time of peeling, and the pressure-sensitive adhesive layer is aggregated and broken at the time of peeling, and the particles cause the work. Contamination of the adherend can be suppressed. The lower limit of the adhesive force with respect to the silicon wafer after irradiation with active energy rays is, for example, preferably 10 mN / 25 mm or more, particularly preferably 20 mN / 25 mm or more, and further preferably 30 mN / 25 mm or more. Is preferable.

The details of the method for measuring the adhesive force before and after the above-mentioned irradiation with the active energy beam are as described in the test examples described later.

(3) Number of Particles In the work processing sheet according to the present embodiment, the pressure-sensitive adhesive layer is irradiated with ultraviolet rays with the surface (adhesive surface) opposite to the base material of the pressure-sensitive adhesive layer attached to the silicon wafer. When the work sheet is peeled off, the number of residues (particles) having a maximum diameter of 0.27 μm or more adhering to the exposed surface of the silicon wafer exposed by the peeling is preferably 1000 or less. The number is preferably 500 or less, and more preferably 300 or less. Since the work processing sheet according to the present embodiment can satisfactorily suppress contamination of the adherend, the number of particles described above can be realized. The details of the method for measuring the number of particles described above are as described in the test examples described later.

3. 3. Method for Manufacturing Work Sheet The method for manufacturing a work sheet according to the present embodiment is not particularly limited. For example, it is preferable to obtain a work processing sheet by forming a pressure-sensitive adhesive layer on the release sheet and then laminating one side of the base material on the surface of the pressure-sensitive adhesive layer opposite to the release sheet.

The above-mentioned adhesive layer can be formed by a known method. For example, a pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer and, if desired, a coating liquid containing a solvent or a dispersion medium are prepared. Then, the coating liquid is applied to the peelable surface of the release sheet (hereinafter, may be referred to as "peeling surface"). Subsequently, the pressure-sensitive adhesive layer can be formed by drying the obtained coating film.

The above-mentioned coating liquid can be applied by a known method, for example, by a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like. The properties of the coating liquid are not particularly limited as long as it can be coated, and the coating liquid may contain a component for forming the pressure-sensitive adhesive layer as a solute or as a dispersoid. .. Further, the release sheet may be peeled off as a process material, or the pressure-sensitive adhesive layer may be protected until it is attached to the adherend.

When the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer contains the above-mentioned cross-linking agent, it is applied by changing the above-mentioned drying conditions (temperature, time, etc.) or by separately providing a heat treatment. It is preferable to proceed the cross-linking reaction between the polymer component in the film and the cross-linking agent to form a cross-linked structure in the pressure-sensitive adhesive layer at a desired abundance density. Further, in order to sufficiently proceed the above-mentioned cross-linking reaction, after the pressure-sensitive adhesive layer and the base material are bonded to each other, curing may be performed such as allowing the adhesive layer to stand in an environment at 23 ° C. and a relative humidity of 50% for several days. ..

4. Method of Using Work Sheet The work processing sheet according to the present embodiment can be used for processing a work such as a semiconductor wafer. That is, after the adhesive surface of the work processing sheet according to the present embodiment is attached to the work, the work can be processed on the work processing sheet. Depending on the processing, the work processing sheet according to the present embodiment will be used as a back grind sheet, a dicing sheet, an expand sheet, a pickup sheet and the like. Here, examples of the work include semiconductor wafers, semiconductor members such as semiconductor packages, and glass members such as glass plates.

As described above, the work processing sheet according to the present embodiment can exhibit excellent antistatic properties while suppressing contamination of the adherend at the time of peeling after irradiation with active energy rays. Therefore, by using the work processing sheet according to the present embodiment, it is possible to effectively suppress contamination and destruction of the work and the fine structure of the work surface. In this respect, the work processing sheet according to the present embodiment is preferably used as a dicing sheet or a pickup sheet, which often handles fine workpieces among the above-mentioned work processing sheets.

When the processing of the work is completed on the work processing sheet according to the present embodiment and the processed work is separated from the work processing sheet, the pressure-sensitive adhesive layer on the work processing sheet is subjected to before the separation. It is preferable to irradiate with active energy rays. As a result, the adhesive layer is hardened, the adhesive force of the work processing sheet to the processed work is satisfactorily lowered, and the processed work can be easily separated.

As the above-mentioned active energy beam, for example, an electromagnetic wave or a charged particle beam having an energy quantum can be used, and specifically, ultraviolet rays, electron beams, or the like can be used. In particular, ultraviolet rays that are easy to handle are preferable. The irradiation of ultraviolet rays can be performed by a high-pressure mercury lamp, a xenon lamp, an LED, or the like, and the irradiation amount of ultraviolet rays is preferably 50 mW / cm ² or more and 1000 mW / cm ² or less. The amount of light is preferably 50 mJ / cm ² or more, particularly preferably 80 mJ / cm ² or more, and further preferably 200 mJ / cm ² or more. The amount of light is preferably 10,000 mJ / cm ² or less, particularly preferably 5000 mJ / cm ² or less, and further preferably 2000 mJ / cm ² or less. On the other hand, the irradiation of the electron beam can be performed by an electron beam accelerator or the like, and the irradiation amount of the electron beam is preferably 10 quad or more and 1000 quad or less.

When the work processing sheet according to the present embodiment includes the above-mentioned adhesive layer, the work processing sheet can be used as a dicing / die bonding sheet. Further, when the work processing sheet according to the present embodiment includes the above-mentioned protective film forming layer, the work processing sheet can be used as a protective film forming and dicing sheet.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, another layer may be laminated between the base material and the pressure-sensitive adhesive layer in the work processing sheet according to the present embodiment, or on the surface of the base material opposite to the pressure-sensitive adhesive layer.

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Example 1]
(1) Preparation of acrylic polymer (A3) in which an active energy ray-curable group is introduced into the side chain 55 parts by mass of n-butyl acrylate, 17 parts by mass of N-acryloylmorpholine, and 2-hydroxy acrylate. 28 parts by mass of ethyl, 0.25 parts by mass of azobisisobutyronitrile (solid content concentration 0.1% by mass) as a polymerization initiator, and ethyl acetate as a solvent were used in a stirrer, a condenser, a thermometer, and a thermometer. It was put into a reaction apparatus equipped with a nitrogen introduction tube and reacted at 60 ° C. for 24 hours in a nitrogen atmosphere to obtain a solution (solid content concentration 40% by mass) containing a (meth) acrylic acid ester polymer. The weight average molecular weight of the (meth) acrylic acid ester polymer was measured by the method described below and found to be 500,000.

After adding methyl ethyl ketone to the obtained solution to make the solid content concentration 35% by mass, 0.05 parts by mass of dibutyltin dilaurate (DBTDL) and the above (meth) acrylic with respect to 100 parts by mass of the solution. To the side chain, 2-methacryloyloxyethyl isocyanate (MOI) in an amount corresponding to 90 mol% was added to 2-hydroxyethyl acrylate constituting the acid ester polymer and reacted at 50 ° C. for 24 hours. An acrylic polymer (A3) into which an active energy ray-curable group was introduced was obtained. The weight average molecular weight of the acrylic polymer (A3) was measured by the method described below and found to be 500,000.

Here, the weight average molecular weight (Mw) of the above-mentioned (meth) acrylic acid ester polymer and the acrylic polymer (A3) is measured by gel permeation chromatography (GPC) under the following conditions (GPC measurement). It is the weight average molecular weight in terms of standard polystyrene.
<Measurement conditions>
-Measuring device: HLC-8320 manufactured by Tosoh Corporation
-GPC column (passed in the following order): TSK gel superH-H manufactured by Tosoh Corporation
TSK gel superHM-H
TSK gel superH2000
・ Measurement solvent: Tetrahydrofuran ・ Measurement temperature: 40 ° C

(2) Preparation of active energy ray-curable antistatic polymer (B) 45 parts by mass of [2- (methacryloyloxy) ethyl] trimethylammonium bis (trifluoromethylsulfonyl) imide as a quaternary ammonium salt monomer (B1), reaction 5 parts by mass of methacrylic acid as the sex functional group-containing monomer (B2), 38 parts by mass of 2-ethylhexyl acrylate and 5 parts by mass of 2-hydroxyethyl acrylate as the polymerizable monomer (B3) were copolymerized. The obtained polymer is reacted with 7 parts by mass of glycidyl methacrylate as a curable group-containing compound (B4) to add an active energy ray-curable antistatic polymer (B) (methacrylic acid group and quaternary ammonium salt to the side chain). Has.) Was obtained. The content of the active energy ray-curable group per unit mass of this active energy ray-curable antistatic polymer (B) was 4.92 × ^10-2 mol / g.

When the weight average molecular weight of the obtained active energy ray-curable antistatic polymer (B) was measured by gel permeation chromatography (GPC) under the following measurement conditions, it was 30,000 as a standard polystyrene equivalent value.
<Measurement conditions>
-Measuring device: HCL-8020 manufactured by Tosoh Corporation
-GPC column (passed in the following order): TSK gel MH-XL manufactured by Tosoh Corporation
TSK gel GMH-XL
TSK gel G2000H-XL
・ Measurement solvent: Tetrahydrofuran ・ Measurement temperature: 40 ° C

(3) Preparation of Adhesive Composition The acrylic polymer (A3) obtained in (1) above, in which an active energy ray-curable group is introduced into the side chain, is 100 parts by mass (in terms of solid content) and the above (in terms of solid content). A compound having 17.7 parts by mass of the active energy ray-curable antistatic polymer (B) obtained in 2) and the structure of the above-mentioned formula (2) as an ionic liquid (C) as a basic structure (Koei Chemical Co., Ltd.). , Product name "IL-OH9") 0.2 parts by mass, Tripolymer propane-modified tolylene diisocyanate as a cross-linking agent (D) (manufactured by Toso Co., Ltd., product name "Coronate L") 0.2 parts by mass. 2-Hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propane-1-one as a photopolymerization initiator (manufactured by BASF, product) The name "Omnirad 127") was mixed with 1.1 parts by mass, stirred sufficiently, and diluted with methyl ethyl ketone to obtain a coating solution (solid content concentration: 30% by mass) of the pressure-sensitive adhesive composition.

(4) Preparation of Work Sheet For the peeling surface of a release sheet (manufactured by Lintec Corporation, product name "SP-PET3801") in which a silicone-based release agent layer is formed on one side of a 38 μm-thick polyethylene terephthalate film. Then, the coating liquid of the pressure-sensitive adhesive composition obtained in the above step (3) is applied and dried at 90 ° C. for 1 minute to form a pressure-sensitive adhesive layer having a thickness of 10 μm on the release sheet. I got a body.

Subsequently, one side of a polyvinyl chloride (PVC) film having a thickness of 80 μm as a base material and the surface on the pressure-sensitive adhesive layer side of the obtained laminate as described above are bonded together, and then the temperature is 23 ° C., relative to each other. A work processing sheet was obtained by storing in an environment of 50% humidity for 3 weeks.

[Examples 2 to 9]
The composition of the acrylic polymer (A3) in which the active energy ray-curable group is introduced into the side chain, the content of the active energy ray-curable antistatic polymer (B), and the type and content of the ionic liquid (C). Was changed as shown in Table 1, and a workpiece processing sheet was obtained in the same manner as in Example 1.

[Comparative Example 1]
A work processing sheet was obtained in the same manner as in Example 1 except that the active energy ray-curable antistatic polymer (B) and the ionic liquid (C) were not used.

[Comparative Examples 2 to 4]
A work processing sheet was obtained in the same manner as in Example 1 except that the ionic liquid (C) was not used and a substitute additive was used instead as shown in Table 1.

[Comparative Example 5]
The work processing sheet was prepared in the same manner as in Example 1 except that the type and content of the ionic liquid (C) were changed as shown in Table 1 and the active energy ray-curable antistatic polymer (B) was not used. Obtained.

[Comparative Examples 6 to 8]
The composition of the acrylic polymer (A3) in which the active energy ray-curable group was introduced into the side chain and the content of the active energy ray-curable antistatic polymer (B) were changed as shown in Table 1 and the ions were changed. A work processing sheet was obtained in the same manner as in Example 1 except that the liquid (C) was not used.

[Comparative Example 9]
20 parts by mass of 2-ethylhexyl acrylate, 35 parts by mass of methyl acrylate, 40 parts by mass of vinyl acetate, 5 parts by mass of 2-hydroxyethyl acrylate, and azobisisobutyronitrile (solid content) as a polymerization initiator. Concentration 0.1% by mass) 0.25 parts by mass and ethyl acetate as a solvent were put into a reaction apparatus equipped with a stirrer, a condenser, a thermometer, and a nitrogen introduction tube, and at 60 ° C. under a nitrogen atmosphere. The reaction was carried out for 24 hours to obtain a solution (solid content concentration 40% by mass) containing a (meth) acrylic acid ester polymer (acrylic polymer (A1) having no active energy ray curability). The weight average molecular weight of the acrylic polymer (A1) having no active energy ray curability was measured by the above-mentioned method and found to be 500,000.

100 parts by mass of the obtained acrylic polymer (A1) having no active energy ray curability, and tripentaerythritol acrylate, mono and dipentaerythritol acrylate and polypentaerythritol acrylate as active energy ray curable compound (A2). (Manufactured by Osaka Organic Chemical Industry Co., Ltd., product name "Viscoat # 802") 26.7 parts by mass and urethane acrylate as an active energy ray-curable compound (A2) (manufactured by Mitsubishi Chemical Co., Ltd., product name "UV6630B") 17.0 parts by mass, 19.7 parts by mass of the active energy ray-curable antistatic polymer (B) obtained in step (2) of Example 1, and trimethylol propane-modified tolylene as a cross-linking agent (D). 0.75 parts by mass of isocyanate (manufactured by Toso Co., Ltd., product name "Coronate L") and 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl)-as a photopolymerization initiator Benzyl] phenyl} -2-methyl-propane-1-one (manufactured by BASF, product name "Omnirad 127") 1.1 parts by mass is mixed, stirred well, and diluted with methyl ethyl ketone to adhere. A coating solution (solid content concentration: 30% by mass) of the agent composition was obtained.

A work processing sheet was obtained in the same manner as in Example 1 except that the coating liquid of the pressure-sensitive adhesive composition obtained as described above was used.

[Comparative Example 10]
A work processing sheet was obtained in the same manner as in Comparative Example 9, except that the content of the active energy ray-curable compound (A2) was used as shown in Table 1.

[Test Example 1] (Measurement of adhesive strength)
The workpiece processing sheets produced in Examples and Comparative Examples were cut into strips having a width of 25 mm. The release sheet is peeled off from the obtained strip-shaped work processing sheet, and the adhesive surface of the exposed adhesive layer is mirror-processed with respect to the mirror surface of the silicon wafer at a temperature of 23 ° C. and a relative humidity of 50%. It was attached using a 2 kg rubber roller in an environment and allowed to stand for 20 minutes to prepare a sample for measuring adhesive strength.

The obtained sample for measuring adhesive strength was obtained from a silicon wafer using a universal tensile tester (manufactured by Orientec, product name "Tencilon UTM-4-100") at a peeling speed of 300 mm / min and a peeling angle of 180 °. The work sheet was peeled off, and the adhesive force (mN / 25 mm) to the silicon wafer was measured by the 180 ° peeling method according to JIS Z0237: 2009. The adhesive strength obtained by this is shown in Table 2 as the adhesive strength before UV irradiation.

Further, the pressure-sensitive adhesive layer in the adhesive force measurement sample obtained in the same manner as described above is subjected to ultraviolet rays (UV) using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2000") via a base material. (Illuminance: 230 mW / cm ² , light intensity: 190 mJ / cm ² ) to cure the pressure-sensitive adhesive layer. Then, the adhesive force (mN / 25 mm) with respect to the silicon wafer was measured in the same manner as described above. The adhesive strength obtained by this is shown in Table 2 as the adhesive strength after UV irradiation.

[Test Example 2] (Measurement of surface resistivity)
The workpiece processing sheet produced in Examples and Comparative Examples was cut into 100 mm × 100 mm, and this was used as a sample for surface resistivity measurement. After adjusting the humidity of the surface resistivity measuring sample at 23 ° C. and 50% relative humidity for 24 hours, the release sheet is peeled off, and the surface resistivity of the adhesive surface is applied using DIGITAL ELECTROMETER (manufactured by ADVANTEST). It was measured at a voltage of 100 V. The results are shown in Table 1. The surface resistivity (Ω / □) thus obtained is shown in Table 2 as the surface resistivity before UV irradiation.

Further, the pressure-sensitive adhesive layer in the surface resistance measurement sample obtained in the same manner as described above is subjected to ultraviolet rays (UV) using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name “RAD-2000”) via a base material. ) (Illuminance: 230 mW / cm ² , light intensity: 190 mJ / cm ² ) to cure the pressure-sensitive adhesive layer. Then, the surface resistivity (Ω / □) was measured in the same manner as above. The adhesive strength obtained by this is shown in Table 2 as the surface resistivity after UV irradiation.

[Test Example 3] (Evaluation of wafer contamination)
The release sheet was peeled off from the work processing sheet manufactured in Examples and Comparative Examples, bonded onto a 6-inch silicon wafer with an adhesive layer, and laminated by applying a load by reciprocating a 5 kg roller once. After allowing this to stand at 23 ° C. and 50% RH for 24 hours, the pressure-sensitive adhesive layer is exposed to ultraviolet rays using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2000") via a base material. (UV) was irradiated (illuminance: 230 mW / cm ² , light intensity: 190 mJ / cm ² ) to cure the pressure-sensitive adhesive layer.

Subsequently, the work processing sheet was peeled from the silicon wafer at a peeling speed of 300 mm / min and a peeling angle of 180 °. Then, on the surface of the silicon wafer to which the work processing sheet was attached, a wafer surface inspection device (manufactured by Topcon, product name "WM-7S") was used to obtain a residue (particle) having a maximum diameter of 0.27 μm or more. The number was measured. The results are shown in Table 2.

[Test Example 4] (Evaluation of pick-up property)
One side of a 6-inch silicon wafer was ground using a grinder (manufactured by Disco Corporation, product name "DFG8540") until the thickness became 150 μm. The surface roughness of the ground surface of the obtained silicon wafer was measured and found to be # 2000. The exposed surface of the pressure-sensitive adhesive layer exposed by peeling the release sheet from the work processing sheet produced in Examples and Comparative Examples was attached to the ground surface using a laminator.

Twenty minutes after the application, the silicon wafer was separated into chips by dicing under the following dicing conditions using a dicing device (manufactured by Disco Corporation, product name "DFD6362").
Dicing conditions Chip size: 10 mm x 10 mm
Cutting height: 65 μm
Blade: Product name "ZH05-SD2000-Z1-90 CC"
Blade rotation speed: 35000 rpm
Cutting speed: 50 mm / sec
Cutting water volume: 1.0 L / min
Cutting water temperature: 20 ° C

After dicing, the surface of the work processing sheet on the substrate side is irradiated with ultraviolet rays (UV) using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2000m12") (illuminance: 230 mW / cm ² , The amount of light was 190 mJ / cm ² ) to cure the pressure-sensitive adhesive layer.

Next, using a pickup device, the insert was pushed up with a needle at a push-up height of 300 μm while expanding the work processing sheet at room temperature with an expand amount of 3 mm. Then, at the same time as the push-up, an attempt was made to separate the insert from the work processing sheet with a collet having a size of 10 mm × 10 mm. When such a pickup operation was repeated 3 times and picked up 3 times in a row without any abnormality, it was evaluated as "〇", and when it could not be picked up, it was evaluated as "x". The results are shown in Table 2.

The details of the abbreviations and the like shown in Table 1 are as follows.
BA: n-butyl acrylate ACMO: N-acryloylmorpholine HEA: 2-hydroxyethyl acrylate MOI: 2-methacryloyloxyethyl isocyanate MMA: methyl methacrylate 2EHA: 2-ethylhexyl acrylate MA: methyl acrylate VAc: acetate Vinyl Viscoat # 802: A mixture of tripentaerythylitol acrylate, mono and dipentaerythylitol acrylate and polypentaerythylitol acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd., product name "Viscoat # 802"
UV6630B: Urethane acrylate, manufactured by Mitsubishi Chemical Corporation, product name "UV6630B"
IL-OH9: A compound having the structure of the above-mentioned formula (2) as a basic structure, manufactured by Koei Chemical Industry Co., Ltd., product name "IL-OH9".
IL-OH2: A compound having the structure of the above-mentioned formula (1) as a basic structure, manufactured by Koei Chemical Industry Co., Ltd., product name "IL-OH2".
IL-MA2: A compound having the structure of the above-mentioned formula (3) as a basic structure, manufactured by Koei Chemical Industry Co., Ltd., product name "IL-MA2".
IL-A2: A compound having the structure of the above-mentioned formula (4) as a basic structure, manufactured by Koei Chemical Industry Co., Ltd., product name "IL-A2".
EO-modified polyglycerin: EO-modified polyglycerin, manufactured by Sakamoto Pharmaceutical Co., Ltd., product name "PG310-6EO"
EO-modified sucrose: EO-modified sucrose, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name "N-14001"

As is clear from Table 2, in the work processing sheet produced in the examples, both the surface resistivity and the number of particles after UV irradiation were suppressed to be low. That is, it was found that the work processing sheet produced in the examples can exhibit excellent antistatic properties while suppressing contamination of the adherend at the time of peeling after irradiation with active energy rays.

The work processing sheet of the present invention can be suitably used for processing a work such as a semiconductor wafer.

Claims (9)

A work processing sheet including a base material and an adhesive layer laminated on one side of the base material.
The pressure-sensitive adhesive layer
With quaternary ammonium salts and polymers with active energy ray-curable groups,
Active energy ray-curable adhesive component (excluding the above polymer),
A work processing sheet characterized by being formed from a pressure-sensitive adhesive composition containing an ionic liquid. The work processing sheet according to claim 1, wherein the cation component constituting the ionic liquid has at least one of a hydroxy group and a vinyl group. The cationic components constituting the ionic liquid are the following formulas (1) to (4).

(In each of the above formulas (1) to (4), R ₁ to R ₄ are independently hydrogen atoms or alkyl groups having 1 to 20 carbon atoms, and n is independently 0 to 20. It is an integer.)
The work processing sheet according to claim 1 or 2, wherein the work sheet has at least one structure shown in 1. The content of the ionic liquid in the pressure-sensitive adhesive composition is 0.5 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the active energy ray-curable pressure-sensitive adhesive component. The work processing sheet according to any one of 1 to 3. The work processing sheet according to any one of claims 1 to 4, wherein the polymer has a weight average molecular weight of 500 or more and 200,000 or less. Claims 1 to 5 are characterized in that the content of the polymer in the pressure-sensitive adhesive composition is 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the active energy ray-curable pressure-sensitive adhesive component. The work processing sheet according to any one of the above. The work processing according to any one of claims 1 to 6, wherein the active energy ray-curable adhesive component contains an acrylic polymer having an active energy ray-curable group introduced into the side chain. Sheet for. The work processing sheet according to any one of claims 1 to 7, wherein the pressure-sensitive adhesive composition does not contain an alkali metal salt. The work processing sheet according to any one of claims 1 to 8, wherein the dicing sheet is used.