JP6656222B2 - Semiconductor processing sheet - Google Patents

Description

  The present invention relates to a semiconductor processing sheet.

  In a process of grinding and cutting a semiconductor wafer, an adhesive sheet is used for the purpose of fixing the semiconductor wafer and protecting circuits and the like. Such an adhesive sheet was provided with an energy-ray-curable adhesive layer, which has a strong adhesive force in the processing step after the semiconductor wafer is attached, and on the other hand, the adhesive force is reduced by irradiation with energy rays at the time of peeling. There is an adhesive sheet.

  These pressure-sensitive adhesive sheets are peeled off when a predetermined processing step is completed. At this time, the pressure-sensitive adhesive sheet and a semiconductor wafer or a semiconductor chip (hereinafter, may be simply referred to as a “chip”) as an adherend and the like are used. In some cases, static electricity called exfoliation charging may be generated. Such static electricity causes destruction of semiconductor wafer chips and circuits formed thereon. In order to prevent this, it is known that a pressure-sensitive adhesive sheet used in processing a semiconductor wafer is provided with an antistatic property by adding a low molecular weight quaternary ammonium salt compound to the pressure-sensitive adhesive.

  However, when a low molecular weight quaternary ammonium salt compound is used as an antistatic agent, the compound may bleed out from the pressure-sensitive adhesive sheet, or residue (particles) of the pressure-sensitive adhesive may adhere to adherends such as semiconductor wafers and chips. There is a problem that the surface is contaminated.

  On the other hand, as a pressure-sensitive adhesive having an antistatic property, an antistatic pressure-sensitive adhesive for optical members using a (meth) acrylic copolymer having a quaternary ammonium salt as an adhesive component 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 have a high molecular weight.

JP 2011-12195 A

  However, the pressure-sensitive adhesive disclosed in Patent Literature 1 is used for a pressure-sensitive adhesive sheet attached to an optical member such as a polarizing plate, and does not assume separation by energy beam irradiation. Therefore, the required physical properties are completely different from those of an adhesive sheet used for semiconductor processing, which greatly changes the adhesive strength before and after irradiation with energy rays.

  Here, the pressure-sensitive adhesive disclosed in Patent Literature 1 is one in which an antistatic property is imparted to the pressure-sensitive adhesive component itself. In such an antistatic pressure-sensitive adhesive component, for example, in order to apply to semiconductor processing, if the composition of the antistatic pressure-sensitive component is changed in order to control any of its adhesiveness or antistatic property, the other The characteristics are also affected. Therefore, the degree of freedom in designing such antistatic pressure-sensitive adhesive components is limited.

  The present invention has been made in view of the above situation, and has a sufficient antistatic property, and can suppress contamination of an adherend at the time of peeling after irradiation with energy rays. It is intended to provide a sheet for use.

  In order to achieve the above object, first, the present invention is a semiconductor processing sheet including a base material and an adhesive layer laminated on at least one surface side of the base material, wherein the adhesive The layer is formed from a pressure-sensitive adhesive composition containing a salt and a polymer having an energy-ray-curable group, and an energy-ray-curable pressure-sensitive adhesive component different from the polymer. It contains a structural unit having a bond and a compound having an energy ray-curable group as one component of the energy ray-curable adhesive component, or has a structural unit having an ether bond as a side chain of the polymer. A semiconductor processing sheet is provided (Invention 1).

  Examples of the semiconductor processing sheet according to the present invention include, for example, a dicing sheet used in a dicing step of a semiconductor wafer and various packages, and a back grinding sheet used in a back grinding step of a semiconductor wafer and the like. It is not limited. The semiconductor processing sheet according to the present invention can be preferably used particularly as a dicing sheet.

  The semiconductor processing sheet according to the present invention includes a sheet having another pressure-sensitive adhesive layer (and a base material) for attaching a ring frame, for example, an annular adhesive sheet surrounding a portion to be attached to a wafer. It shall include those provided with members. Further, the sheet for semiconductor processing according to the present invention, the pressure-sensitive adhesive layer is provided partially on the substrate, for example, the pressure-sensitive adhesive layer is provided only on the peripheral portion of the substrate, the inner peripheral portion Include those without an adhesive layer. Further, the term “sheet” in the present invention includes the concept of “tape”.

  The semiconductor processing sheet according to the above invention (Invention 1) has a sufficient effect that the polymer contained in the pressure-sensitive adhesive composition has a salt (cation) and the pressure-sensitive adhesive composition contains a structural unit having an ether bond. Exhibits antistatic properties. Further, the polymer has an energy ray-curable group, and the structural unit having an ether bond is included in the pressure-sensitive adhesive composition as a compound having an energy ray-curable group or as a side chain of the polymer. By energy beam irradiation, between the polymers, between the polymer and the energy ray-curable component, or between a compound having a structural unit having an ether bond and an energy ray-curable group and the polymer and the energy ray-curable component React between and crosslink. Accordingly, when the adherend is peeled off after the irradiation with the energy beam, generation of particles adhering to the adherend is reduced, and contamination of the adherend can be suppressed. Here, the structural unit having an ether bond and the compound having an energy ray-curable group are contained as one component of the energy ray-curable adhesive component, and also contribute to the energy ray curability of the adhesive component.

  In the above invention (Invention 1), the structural unit having an ether bond is preferably an alkylene oxide unit (Invention 2), and the alkylene oxide unit is preferably a repeating unit of 2 to 40 (Invention 3).

  In the above inventions (Inventions 1 to 3), the content of the polymer in the pressure-sensitive adhesive composition is preferably 0.5 to 65% by mass (Invention 4).

  In the above inventions (Inventions 1 to 4), the polymer preferably has a weight average molecular weight of 500 to 200,000 (Invention 5).

  In the above inventions (Inventions 1 to 5), the polymer preferably has a (meth) acryloyl group as the energy ray-curable group (Invention 6).

In the above inventions (Inventions 1 to 6), the content of the energy ray-curable group per unit mass of the polymer is preferably 5 × 10 ⁻⁵ to 2 × 10 ⁻³ mol / g (Invention 7) ).

  In the above inventions (Inventions 1 to 7), the energy ray-curable adhesive component may contain an acrylic polymer having no energy ray curability and an energy ray-curable compound (Invention 8), It may contain an acrylic polymer having an energy ray-curable group introduced into a side chain (Invention 9).

  In the above inventions (Inventions 1 to 9), the energy ray-curable adhesive component preferably contains a crosslinking agent (Invention 10).

  In the above inventions (Inventions 1 to 10), the salt is preferably a quaternary ammonium salt (Invention 11).

  ADVANTAGE OF THE INVENTION The sheet | seat for semiconductor processing which concerns on this invention can suppress contamination of the to-be-adhered body, such as a wafer and a chip, at the time of peeling after irradiation of energy rays, while exhibiting sufficient antistatic property.

It is sectional drawing of the sheet | seat for semiconductor processing which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a sectional view of a semiconductor processing sheet according to an embodiment of the present invention. The semiconductor processing sheet 1 according to the present embodiment includes a substrate 2 and an adhesive layer 3 laminated on one surface (the upper surface in FIG. 1) of the substrate 2. The semiconductor processing sheet 1 according to the present embodiment can be used as a dicing sheet, a back-grinding sheet, and the like. Hereinafter, a description will be given mainly of a case where the sheet is used as a dicing sheet.

1. Substrate The base material 2 of the semiconductor processing sheet 1 according to the present embodiment is made of any material as long as the semiconductor processing sheet 1 can function properly in a desired process such as a dicing process, an expanding process, or a back grinding process. It is not limited, and is usually composed of a film mainly composed of a resin material. Specific examples of the film include ethylene-based copolymer films such as an ethylene-vinyl acetate copolymer film, an ethylene- (meth) acrylic acid copolymer film, and an ethylene- (meth) acrylic ester copolymer film; Polyethylene (LDPE) film, linear low density polyethylene (LLDPE) film, polyethylene film such as high density polyethylene (HDPE) film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film, Polyolefin films such as norbornene resin films; polyvinyl chloride films such as polyvinyl chloride films and vinyl chloride copolymer films; polyethylene terephthalate films, polybutylene tele Polyester film of tallate films; polyurethane film; polyimide film; polystyrene films; polycarbonate films; and fluorine resin film. Modified films such as crosslinked films and ionomer films are also used. The base material 2 may be a film made of one of these materials, or may be a laminated film combining two or more of these materials. In addition, "(meth) acrylic acid" in this specification means both acrylic acid and methacrylic acid. The same applies to other similar terms.

  The film constituting the substrate 2 preferably includes at least one of an ethylene-based copolymer film and a polyolefin-based film. The mechanical properties of an ethylene copolymer film can be easily controlled in a wide range by changing the copolymerization ratio. For this reason, the base material 2 provided with the ethylene-based copolymer film easily satisfies the mechanical properties required as the base material of the semiconductor processing sheet 1 according to the present embodiment. In addition, since the ethylene-based copolymer film has relatively high adhesiveness to the pressure-sensitive adhesive layer 3, peeling at the interface between the base material 2 and the pressure-sensitive adhesive layer 3 hardly occurs when used as a semiconductor processing sheet.

  Here, some films, such as a polyvinyl chloride film, contain many components which have a bad influence on the properties as a sheet for semiconductor processing. For example, in the case of a polyvinyl chloride film or the like, the plasticizer contained in the film migrates from the substrate 2 to the pressure-sensitive adhesive layer 3, and the surface of the pressure-sensitive adhesive layer 3 on the side opposite to the side facing the substrate 2. In some cases, the adhesiveness of the adhesive layer 3 to an adherend (semiconductor wafer, chip, or the like) may be reduced. However, the ethylene-based copolymer film and the polyolefin-based film have a small content of a component that adversely affects the properties of the semiconductor processing sheet, and thus have a problem that the adhesiveness of the adhesive layer 3 to an adherend is reduced. Hard to occur. That is, the ethylene copolymer film and the polyolefin film have excellent chemical stability.

  The base material 2 used in the present embodiment contains various additives such as a pigment, a flame retardant, a plasticizer, an antistatic agent, a lubricant, and a filler in a film containing the above-described resin-based material as a main material. Is also good. Examples of the pigment include titanium dioxide and carbon black. Examples of the filler include an organic material such as a melamine resin, an inorganic material such as fumed silica, and a metal material such as nickel particles. The content of such an additive is not particularly limited, but should be kept within a range in which the base material 2 exhibits a desired function and does not lose smoothness or flexibility.

  In the case where ultraviolet rays are used as energy rays to be applied to cure the pressure-sensitive adhesive layer 3, the base material 2 preferably has transparency to ultraviolet rays. When an electron beam is used as the energy beam, it is preferable that the base material 2 has an electron beam permeability.

  On the surface of the substrate 2 on the side of the pressure-sensitive adhesive layer 3 (hereinafter also referred to as “substrate-adhered surface”), one or two or more selected from the group consisting of a carboxyl group and ions and salts thereof are provided. It is preferable that a component having the same exists. The above components in the base material 2 and the components related to the pressure-sensitive adhesive layer 3 (the components constituting the pressure-sensitive adhesive layer 3 and the components used in forming the pressure-sensitive adhesive layer 3 such as a crosslinking agent are exemplified). By interacting with each other, it is possible to reduce the possibility that separation occurs between them. The specific method for causing such a component to be present on the surface to which the base material is attached is not particularly limited. For example, when the substrate 2 itself is used as an ethylene- (meth) acrylic acid copolymer film, an ionomer resin film, or the like, the resin constituting the substrate 2 is selected from the group consisting of a carboxyl group and ions and salts thereof. One or two or more kinds may be used. As another method for causing the above components to be present on the substrate-adhering surface, the substrate 2 is, for example, a polyolefin-based film, and the substrate-adhering surface is subjected to a corona treatment, or provided with a primer layer. May be. Further, various coating films may be provided on the surface of the substrate 2 opposite to the surface on which the substrate is adhered. These primer layers and coating films may contain an antistatic agent. Thereby, as the semiconductor processing sheet 1, more excellent antistatic performance can be exhibited.

  The thickness of the substrate 2 is not limited as long as the semiconductor processing sheet 1 can appropriately function in a desired process. It is preferably in the range of 20 to 450 μm, more preferably 25 to 400 μm, and particularly preferably 50 to 350 μm.

  The elongation at break of the substrate 2 in the present embodiment is preferably 100% or more, and particularly preferably 200 to 1000%, as measured at 23 ° C. and 50% relative humidity. Here, the elongation at break is an elongation percentage of the length of the test piece at the time of breaking the test piece with respect to the original length in a tensile test based on JIS K7161: 1994 (ISO 527-1 1993). If the elongation at break is 100% or more, the semiconductor processing sheet according to the present embodiment is not easily broken when the semiconductor processing sheet is used in an expanding step, and chips formed by cutting a wafer are easily separated.

  In the present embodiment, the tensile stress at 25% strain of the substrate 2 in the present embodiment is preferably 5 to 15 N / 10 mm, and the maximum tensile stress is preferably 15 to 50 MPa. Here, the tensile stress at 25% strain and the maximum tensile stress are measured by a test based on JIS K7161: 1994. When the tensile stress at the time of 25% strain is 5 N / 10 mm or more and the maximum tensile stress is 15 MPa or more, when the work is attached to the dicing sheet 1 and then fixed to a frame such as a ring frame, the base material 2 becomes loose. Occurrence is suppressed, and occurrence of a transport error can be prevented. On the other hand, when the tensile stress at the time of 25% strain is 15 N / 10 mm or less and the maximum tensile stress is 50 MPa or less, peeling of the dicing sheet 1 from the ring frame during the expanding step is suppressed. The breaking elongation, the tensile stress at 25% strain, and the maximum tensile stress indicate values measured in the longitudinal direction of the raw material in the substrate 2.

2. Pressure-Sensitive Adhesive Layer The pressure-sensitive adhesive layer 3 included in the semiconductor processing sheet 1 according to the present embodiment includes an energy-ray-curable pressure-sensitive adhesive component (A) and a polymer (C) having a salt and an energy-ray-curable group (hereinafter referred to as “energy rays”). Curable antistatic polymer (C) "), and a pressure-sensitive adhesive composition containing a structural unit having an ether bond. The energy ray-curable pressure-sensitive adhesive component (A) does not include the energy ray-curable antistatic polymer (C). Here, the constituent unit having an ether bond is a compound having an ether bond and a compound (B) having an energy ray-curable group (hereinafter, may be referred to as an “ether bond-containing energy ray-curable compound (B)”). As a side chain of the energy ray-curable antistatic polymer (C) in the pressure-sensitive adhesive composition. Moreover, it is preferable that the adhesive composition in this embodiment contains the crosslinking agent (D) mentioned later.

(1) Energy ray-curable adhesive component (A)
The energy ray-curable pressure-sensitive adhesive component (A) contains an acrylic polymer (A1) having no energy ray-curability and an energy ray-curable compound (A2), or has an energy ray-curable group in a side chain. It is preferable that it contains the acrylic polymer (A3) into which is introduced. When the energy ray-curable adhesive component (A) contains an acrylic polymer (A3) having an energy ray-curable group introduced into a side chain, the acrylic polymer (A3) is used as the energy ray-curable adhesive component. Only, or may contain the acrylic polymer (A3) and the acrylic polymer (A1) and / or the energy ray-curable compound (A2) having no energy ray-curability. Good. In addition, the term “polymer” in the present specification includes the concept of “copolymer”.

(1-1) Acrylic polymer having no energy beam curability (A1)
When the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer 3 in the present embodiment contains an acrylic polymer (A1) having no energy ray curability, the acrylic polymer (A1) is added to the pressure-sensitive adhesive composition. It may be contained as it is, or at least a part thereof may be contained as a crosslinked product by performing a crosslinking reaction with a crosslinking agent (D) 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 kind of acrylic monomer, a copolymer formed from a plurality of kinds of acrylic monomers, or 1 It may be a copolymer formed from one or more kinds of acrylic monomers and monomers other than acrylic monomers. The specific type of the compound to be an acrylic monomer is not particularly limited, and specific examples thereof include (meth) acrylic acid, (meth) acrylic acid ester, and derivatives thereof (acrylonitrile, itaconic acid, and the like). More specific examples of (meth) acrylic acid esters include chain skeletons such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. (Meth) acrylate having a cyclic skeleton such as cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, and imide acrylate; 2 -(Meth) acrylates having a hydroxy group such as -hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; hydroxy such as glycidyl (meth) acrylate and N-methylaminoethyl (meth) acrylate And (meth) acrylates having a reactive functional group other than groups. In addition, examples of monomers other than acrylic monomers include olefins such as ethylene and norbornene, vinyl acetate, and styrene. When the acrylic monomer is an alkyl (meth) acrylate, the alkyl group preferably has 1 to 18 carbon atoms.

  When the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer 3 in the present embodiment contains a crosslinking agent (D) described below, the acrylic polymer (A1) reacts with the crosslinking agent (D). It preferably has a functional group. The type of the reactive functional group is not particularly limited, and may be appropriately determined based on the type of the crosslinking agent (D) and the like.

  For example, when the crosslinking agent (D) is an epoxy compound, examples of the reactive functional group of the acrylic polymer (A1) include a carboxyl group, an amino group, and an amide group. Carboxyl groups with high reactivity are preferred. When the crosslinking agent (D) is a polyisocyanate compound, examples of the reactive functional group of the acrylic polymer (A1) include a hydroxy group, a carboxyl group, and an amino 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. As an example, the acrylic polymer (A1) is formed using a monomer having a reactive functional group, and the reactive functional group is formed. A method in which a structural unit based on a monomer having the formula (1) is contained in the skeleton of the polymer. For example, when a carboxyl group is introduced into the acrylic polymer (A1), the acrylic polymer (A1) may be formed using a monomer having a carboxyl group such as (meth) acrylic acid.

  When the acrylic polymer (A1) has a reactive functional group, the monomer derived from the monomer having the reactive functional group occupies the entire mass of the acrylic polymer (A1) from the viewpoint of setting the degree of crosslinking to a favorable range. Is preferably about 1 to 20% by mass, more preferably 2 to 10% by mass.

  The weight average molecular weight (Mw) of the acrylic polymer (A1) is preferably from 10,000 to 2,000,000, and more preferably from 100,000 to 1.5,000,000, from the viewpoint of film forming property at the time of coating. In the present specification, the weight average molecular weights of the acrylic polymers (A1) and (A3) are values in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method, and details of the measuring method will be described later. An example will be shown. The glass transition temperature Tg of the acrylic polymer (A1) is preferably in the range of -70C to 30C, and more preferably in the range of -60C to 20C. The glass transition temperature can be calculated from the Fox equation.

(1-2) Energy ray-curable compound (A2)
When the energy ray-curable pressure-sensitive adhesive component (A) contains the acrylic polymer (A1) having no energy ray-curability, it also contains the energy ray-curable compound (A2). The energy ray-curable compound (A2) is a compound having an energy ray-curable group and polymerizing when irradiated with an energy ray such as an ultraviolet ray or an electron beam. In this specification, the concept of the energy ray-curable compound (A2) includes an ether bond-containing energy ray-curable compound (B) described later.

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

  Examples of the energy ray-curable compound (A2) are not particularly limited as long as they have the above-mentioned energy ray-curable group, but from the viewpoint of versatility, low molecular weight compounds (monofunctional and polyfunctional monomers and oligomers) It is preferred that Specific examples of the low molecular weight energy ray-curable compound (A2) include trimethylolpropane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol monohydroxypenta ( (Meth) acrylate, dipentaerythritol hexa (meth) acrylate or 1,4-butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, dicyclopentadienedimethoxydi (meth) acrylate, isobornyl (meth) acrylate A) acrylates and other cyclic aliphatic skeleton-containing (meth) acrylates, oligoester (meth) acrylates, urethane (meth) acrylate oligomers, epoxy-modified (meth) acrylates, etc. Include acrylate-based compound. In addition, the compound having a structural unit having an ether bond will be described in detail in the section of the energy-curable compound containing an ether bond (B).

  The energy ray-curable compound (A2) generally has a molecular weight of about 100 to 30,000, preferably about 300 to 10,000. In general, the energy ray-curable compound (A2) is used in a proportion of 10 to 400 parts by mass, preferably about 30 to 350 parts by mass, based on 100 parts by mass of the acrylic polymer (A1). Here, when the energy ray-curable pressure-sensitive adhesive component (A) in the present embodiment contains an ether bond-containing energy ray-curable compound (B) described later, the energy containing the ether bond-containing energy ray-curable compound (B) is used. It is preferable that the total use amount of the line-curable compound (A2) is within the above range.

  Further, when the energy ray-curable pressure-sensitive adhesive component (A) contains an acrylic polymer (A3) having an energy ray-curable group introduced into a side chain described later and an energy ray-curable compound (A2). It is preferable that the content of the energy ray-curable compound (A2) is within the above range based on 100 parts by mass of the acrylic polymer (A3). Further, the energy ray-curable pressure-sensitive adhesive component (A) comprises the acrylic polymer (A1), an acrylic polymer (A3) having an energy ray-curable group introduced into a side chain, and an energy ray-curable compound ( A2), the content of the energy ray-curable compound (A2) is within the above range with respect to 100 parts by mass of the total amount of the acrylic polymer (A1) and the acrylic polymer (A3). It is preferred that

(1-3) Acrylic polymer (A3) having an energy ray-curable group introduced into a side chain
When the energy-ray-curable pressure-sensitive adhesive component (A) in the present embodiment contains an acrylic polymer (A3) having an energy-ray-curable group introduced into a side chain, the acrylic polymer (A3) is a pressure-sensitive adhesive. The composition may be contained as it is, or at least a part thereof may be contained as a crosslinked product by performing a crosslinking reaction with a crosslinking agent (D) described later.

  The main skeleton of the acrylic polymer (A3) having an energy-ray-curable group introduced into a side chain is not particularly limited, and examples thereof include the same ones as the above-mentioned acrylic polymer (A1).

  The energy ray-curable group introduced into the side chain of the acrylic polymer (A3) is, for example, an energy ray-curable group containing a carbon-carbon double bond, and specifically includes a (meth) acryloyl group and the like. Examples can be given. The 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) having an energy ray-curable group introduced into its side chain is, for example, an acrylic polymer containing a functional group such as a hydroxy group, a carboxyl group, an amino group, a substituted amino group, or an epoxy group. The compound is obtained by reacting a substituent that reacts with the functional group and a curable group-containing compound having 1 to 5 energy ray-curable carbon-carbon double bonds per molecule. Such an acrylic polymer includes a (meth) acrylate monomer having a functional group such as a hydroxy group, a carboxyl group, an amino group, a substituted amino group, or an epoxy group or a derivative thereof, and a monomer constituting the component (A1) described above. And copolymerized from Examples of the curable group-containing compound include (meth) acryloyloxyethyl isocyanate, meta-isopropenyl-α, α-dimethylbenzyl isocyanate, (meth) acryloyl isocyanate, allyl isocyanate, glycidyl (meth) acrylate; and (meth) Acrylic acid and the like can be mentioned.

  In the case where the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3 in the present embodiment contains a crosslinking agent (D) described later, an acrylic polymer having an energy-ray-curable group introduced into a side chain ( A3) preferably has a reactive functional group that reacts with the crosslinking agent (D). The type of the reactive functional group is not particularly limited, and examples thereof include those similar to the acrylic polymer (A1) described above.

  The weight average molecular weight (Mw) of the acrylic polymer (A3) having an energy ray-curable group introduced into a side chain is preferably from 100,000 to 2,000,000, more preferably from 300,000 to 1,500,000. .

  The glass transition temperature (Tg) of the acrylic polymer (A3) is preferably in the range of -70 to 30C, more preferably in the range of -60 to 20C. In this specification, the glass transition temperature (Tg) of the acrylic polymer (A3) refers to that of the acrylic polymer before being reacted with the curable group-containing compound.

(2) Structural unit having an ether bond The pressure-sensitive adhesive composition according to the present embodiment includes a structural unit having an ether bond. The structural unit having an ether bond is contained in the pressure-sensitive adhesive composition as an energy bond-curable compound (B) containing an ether bond, or is contained in the pressure-sensitive adhesive composition as a side chain of the energy-ray-curable antistatic polymer (C). It is.

  The structural unit having an ether bond exhibits antistatic properties depending on the polarity of the ether bond. Further, since the structural unit having an ether bond is included in the pressure-sensitive adhesive composition as the energy bond-curable compound (B) containing an ether bond or as a side chain of the energy-ray-curable antistatic polymer (C), the energy ray By irradiation, it crosslinks by reacting with the energy ray-curable adhesive component (A) and the energy ray-curable antistatic polymer (C). Accordingly, when the adherend is peeled off after the irradiation with the energy beam, the generation of particles derived from the component having an ether bond, which adheres to the adherend, is reduced, and contamination of the adherend can be suppressed.

  Here, the ether bond-containing energy ray-curable compound (B) has not only an ether bond in the molecule but also an energy ray-curable group, and is irradiated with energy rays such as ultraviolet rays and electron beams. It is a compound that polymerizes. That is, the energy ray-curable compound (B) containing an ether bond is included in the concept of the energy ray-curable compound (A2) described above. In the present embodiment, as the energy ray-curable compound (A2), only one or two or more compounds classified as the ether bond-containing energy ray-curable compound (B) may be used. One or two or more compounds classified as the hydrophilic compound (B) and the energy ray-curable compound (A2) which is not classified as the ether bond-containing energy ray-curable compound (B) (has no ether bond) 1 Alternatively, two or more compounds may be used in combination.

  In the present embodiment, the structural unit having an ether bond is included as an ether bond-containing energy ray-curable compound (B) or as a side chain of the energy ray-curable antistatic polymer (C). May be included in any one form, or may be included in both forms. Here, when the structural unit having an ether bond is contained as the ether bond-containing energy ray-curable compound (B), the structural unit having an ether bond is uniformly distributed in the pressure-sensitive adhesive layer 3 formed from the pressure-sensitive adhesive composition. Therefore, the effect of improving the antistatic performance is more easily exhibited than when it is contained as a side chain of the energy ray-curable antistatic polymer (C).

  In addition, the structural unit having an ether bond may be an acrylic polymer (A1) having no energy beam curability, or an energy beam curable group introduced into a side chain of the energy beam curable pressure-sensitive adhesive component (A). May be contained in the acrylic polymer (A3). However, the acrylic polymers (A1) and (A3) are components that impart tackiness to the pressure-sensitive adhesive layer 3, and when these do not contain a structural unit having an ether bond, the pressure-sensitive adhesive layer 3 has It is more preferable because the design of the sex becomes easier. For example, the adhesive strength of the semiconductor processing sheet 1 before and after the irradiation with the energy beam and the force required for picking up the chip after dicing and irradiating the energy beam (for example, a 5 mm square pickup force described later) are set to desired values. Becomes easier.

  Examples of the structural unit having an ether bond include an alkylene oxide unit such as an ethylene oxide unit, a propylene oxide unit, a butylene oxide unit, a pentene oxide unit, and a hexene oxide unit; an alkoxy group such as a methoxy group, an ethoxy group, and a butoxy group; A functional group containing a cyclic ether such as a furyl group; and the like, and among these, an alkylene oxide unit is preferable.

  The alkylene oxide unit has about 1 to 8 carbon atoms since the abundance of the ether bond in the pressure-sensitive adhesive composition can be increased without increasing the molecular weight of the ether bond-containing energy ray-curable compound (B). It is more preferably about 1 to 4 carbon atoms, and particularly preferably ethylene oxide having 2 carbon atoms.

  The alkylene oxide unit may be one, but is preferably contained in two or more repetitions, and the number of repetitions is more preferably 2 to 40, further preferably 3 to 30. When the alkylene oxide unit is repeatedly contained, the antistatic property is more effectively exhibited. Here, when the alkylene oxide unit is included in the ether bond-containing energy ray-curable compound (B), the number of repetitions is particularly preferably 2 to 20. On the other hand, when the alkylene oxide unit is included as a side chain of the energy ray-curable antistatic polymer (C), the number of repetitions is particularly preferably 5 to 40.

  When the structural unit having an ether bond is included in the pressure-sensitive adhesive composition as the energy bond-curable compound (B) containing an ether bond, the energy-ray-curable group of the compound (B) is, for example, an energy-ray-curable carbon. A group containing a carbon double bond, specifically, a (meth) acryloyl group and a vinyl group, among which a (meth) acryloyl group is preferable.

  In addition, the ether bond-containing energy ray-curable compound (B) can react with the energy ray-curable pressure-sensitive adhesive component (A) or the like after irradiation with energy rays by having one or more energy ray-curable groups. From the viewpoint of effectively forming a crosslinked structure, it is preferable to have two or more energy ray-curable groups.

  The ether bond-containing energy ray-curable compound (B) is not particularly limited as long as it has a structural unit having an ether bond and an energy ray-curable group, and examples thereof include tetraethylene glycol di (meth) acrylate and the like. Diacrylate, which is an ester of polyalkylene glycol and (meth) acrylic acid, ethoxy-modified glycerin tri (meth) acrylate, ethoxy-modified pentaerythritol tetra (meth) acrylate, and (meth) acrylate at the end of the reaction product of polyether polyol and polyisocyanate Examples thereof include urethane (meth) acrylate to which an acryloyl group has been added, and one type may be used alone or two or more types may be used in combination. Among these, tetraethylene glycol di (meth) acrylate is particularly preferred.

  The content of the ether bond-containing energy ray-curable compound (B) in the pressure-sensitive adhesive composition of the present embodiment is preferably from 3 to 40% by mass, particularly preferably from 5 to 30% by mass, and preferably from 8 to 30% by mass. More preferably, it is 25% by mass.

  In addition, when the energy beam-curable compound (B) containing an ether bond (the energy beam-curable adhesive component (A) contains an energy beam-curable compound (A2) having no ether bond, the energy beam-curable compound containing an ether bond is used. The total amount of the compound (B) and the energy ray-curable compound (A2) having no ether bond) is 100% by mass of the acrylic polymer (A1) or the like, similarly to the energy ray-curable compound (A2) described above. It is used at a ratio of about 10 to 400 parts by mass, preferably about 30 to 350 parts by mass with respect to parts. When the amount is 400 parts by mass or less, the cohesive force of the pressure-sensitive adhesive layer 3 before the energy ray irradiation is maintained at a high level, and the pressure-sensitive adhesive layer 3 has preferable elasticity. The occurrence of chipping at the chip end) is effectively suppressed.

  Here, the used amount of the ether bond-containing energy ray-curable compound (B) (or the total used amount of the ether bond-containing energy ray-curable compound (B) and the energy ray-curable compound having no ether bond (A2)) Is the value with respect to 100 parts by mass of the acrylic polymer (A1) or (A3) when one of the acrylic polymer (A1) and (A3) is used, and the acrylic polymer (A1) When both (A3) and (A3) are used, the value is based on 100 parts by mass of the total amount of the acrylic polymers (A1) and (A3).

  On the other hand, the case where a structural unit having an ether bond is included as a side chain of the energy ray-curable antistatic polymer (C) will be described in detail in the section of the energy ray-curable antistatic polymer (C).

(3) Energy ray-curable antistatic polymer (C)
The pressure-sensitive adhesive composition that forms the pressure-sensitive adhesive layer 3 in the present embodiment includes, in addition to the above-described energy-ray-curable pressure-sensitive adhesive component (A), a polymer having a salt and an energy-ray-curable group (C) (energy-ray-curable (Antistatic polymer (C)).

  The energy ray-curable antistatic polymer (C) exhibits an antistatic property by having a salt (cation). Further, when a structural unit having an ether bond is further provided in the side chain, the structural unit can also exhibit antistatic properties. The energy ray-curable antistatic polymer (C) may have a salt in the main chain or a side chain, but preferably has a salt in a side chain. The salt is composed of a cation and an anion thereof, preferably an onium cation and an anion thereof. Such a salt may be composed of a cation covalently bonded to the energy ray-curable antistatic polymer (C) and an anion thereof, or an anion covalently bonded to the energy ray-curable antistatic polymer (C) and a corresponding anion. And a cation.

  Examples of the salts include quaternary ammonium salts, phosphonium salts, sulfonium salts, oxonium salts, diazonium salts, chloronium salts, iodonium salts, pyrylium salts and the like. One of these can be used alone, or two or more can be used in combination. The quaternary ammonium salt is composed of a quaternary ammonium cation and an anion thereof, and the other salts are similarly composed.

  Among the above, quaternary ammonium salts having excellent antistatic performance are particularly preferred. Here, the “quaternary ammonium cation” means an onium cation of nitrogen, and includes a heterocyclic onium ion such as imidazolium and pyridium. As the quaternary ammonium cation, an alkylammonium cation (herein, “alkyl” includes a hydrocarbon group having 1 to 30 carbon atoms, as well as those substituted with hydroxyalkyl and alkoxyalkyl); Heteromonocyclic cations such as a cation, a pyrium cation, an imidazolium cation, a pyrazolium cation, a pyridinium cation, a piperidinium cation, and a piperazinium cation; an indolium cation, a benzimidazolium cation, a carbazolium cation, Condensed heterocyclic cations such as a norinium cation; All include those in which a hydrocarbon group, a hydroxyalkyl group or an alkoxyalkyl group having 1 to 30 carbon atoms (for example, 1 to 10 carbon atoms) is bonded to a nitrogen atom and / or a ring.

Examples of the anion include, in addition to an anion having a halogen atom, derivatives of oxo acids such as carboxylic acid, sulfonic acid, and phosphoric acid (for example, hydrogen sulfate, methanesulfonate, ethyl sulfate, dimethyl phosphate, 2- (2- Methoxyethoxy) ethyl sulfate, dicyanamide and the like, among which anions having a halogen atom are 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 an aliphatic Anion having a nitrogen atom such as a group), ArSO ₂ —N—SO ₂ CF ₃ ^— (Ar is an aromatic group); C _n 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}} - , etc., anion having a fluorine atom is preferably exemplified as a halogen atom. 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 anion, tetrafluoroborate anion, and hexafluorophosphate anion are particularly preferred.

  Further, the energy ray-curable antistatic polymer (C) has an energy ray-curable group in a side chain, so that the energy ray-curable antistatic polymer ( C), or the energy ray-curable antistatic polymer (C) reacts with the above-mentioned energy ray-curable pressure-sensitive adhesive component (A) to crosslink. Therefore, bleed-out of the energy ray-curable antistatic polymer (C) from the pressure-sensitive adhesive layer 3 is suppressed, and residue (particles) of the pressure-sensitive adhesive is not easily generated when the semiconductor processing sheet 1 is peeled off. The contamination of the adherend can be suppressed.

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

The content of the energy ray-curable group per unit mass of the energy ray-curable antistatic polymer (C) is preferably 5 × 10 ⁻⁵ to 2 × 10 ⁻³ mol / g, and preferably 1 × 10 ^−4. The amount is particularly preferably from 1.5 × 10 ⁻³ mol / g to 3 × 10 ⁻⁴ to 1 × 10 ⁻³ mol / g. When the content of the energy ray-curable group is 5 × 10 ⁻⁵ mol / g or more, the energy ray-curable antistatic polymers (C) by energy ray irradiation, or the energy ray-curable antistatic polymer (C) The crosslinking between the adhesive and the energy ray-curable pressure-sensitive adhesive component (A) is sufficient, and contamination of the adherend by the pressure-sensitive adhesive layer 3 can be effectively suppressed. In addition, when the content of the energy ray-curable group is 2 × 10 ⁻³ mol / g or less, the curing when the pressure-sensitive adhesive layer is cured by the energy ray is not excessive, and the adherend and the adherend after curing are not excessively hardened. Unintended peeling during is suppressed.

  The energy ray-curable antistatic polymer (C) may further have a structural unit having an ether bond in a side chain. In this case, as the structural unit having an ether bond, the same units as those described in the above (2) including the alkylene oxide unit can be exemplified. As mentioned.

  The energy ray-curable antistatic polymer (C) in the present embodiment is, for example, a polymerizable monomer having a salt, particularly a polymerizable monomer having a quaternary ammonium salt (hereinafter, referred to as “quaternary ammonium salt monomer (C1)”). ), A polymerizable monomer having a reactive functional group (hereinafter sometimes referred to as a “reactive functional group-containing monomer (C2)”), and a polymerizable monomer having an ether bond as required (hereinafter referred to as a “ether bond-containing monomer”). Monomer (C3) ") and a copolymerizable monomer (C4), and then containing a curable group having a substituent that reacts with the reactive functional group and an energy ray-curable group. A compound obtained by reacting with compound (C5) is preferable, but not limited thereto.

  The quaternary ammonium salt monomer (C1) has a polymerizable group and a salt composed of a quaternary ammonium cation and an anion thereof, and is preferably a quaternary ammonium cation having a polymerizable group. Consisting of a salt composed of an anion to Examples of the polymerizable group include a cyclic ether having a carbon-carbon unsaturated group such as a (meth) acryloyl group, a vinyl group and an allyl group, an epoxy group and an oxetane group, a cyclic sulfide such as tetrahydrothiophene, and an isocyanate group. And the like, and among them, a (meth) acryloyl group and a vinyl group are preferable.

  Examples of the quaternary ammonium cation having a polymerizable group include a trialkylaminoethyl (meth) acrylate ammonium cation, a trialkylaminopropyl (meth) acrylamide ammonium cation, a 1-alkyl-3-vinylimidazolium cation, and a 4-alkylammonium cation. Vinyl-1-alkylpyridinium cation, 1- (4-vinylbenzyl) -3-alkylimidazolium cation, 1- (vinyloxyethyl) -3-alkylimidazolium cation, 1-vinylimidazolium cation, 1-allylimidazo Lium cation, N-alkyl-N-allylammonium cation, 1-vinyl-3-alkylimidazolium cation, 1-glycidyl-3-alkyl-imidazolium cation, N-allyl-N-alkylpyrroli Cation, (meaning a hydrocarbon group having 1 to 10 carbon atoms and herein "alkyl".) That quaternary diallyl dialkyl ammonium cations and the like. Among these, a trialkylaminoethyl (meth) acrylate ammonium cation (= [2- (methacryloyloxy) ethyl] trialkyl ammonium cation) is preferable.

  The quaternary ammonium salt monomer (C1) may be a salt composed of the quaternary ammonium cation having the polymerizable group and the anion. For example, [2- (methacryloyloxy) ethyl] trimethylammonium bis (Trifluoromethylsulfonyl) imide and the like. The quaternary ammonium salt monomer (C1) can be used alone or in combination of two or more.

  In the energy ray-curable antistatic polymer (C), the proportion of the mass of the structural portion derived from the quaternary ammonium salt monomer (C1) in the total mass of the polymer (C) is preferably from 20 to 80% by mass. The content is particularly preferably from 25 to 75% by mass, and more preferably from 35 to 60% by mass. When the mass ratio of the structural portion derived from the quaternary ammonium salt monomer (C1) is 20% by mass or more, the energy ray-curable antistatic polymer (C) exhibits a sufficient antistatic property. On the other hand, when the proportion of the mass of the structural portion derived from the quaternary ammonium salt monomer (C1) is 80% by mass or less, the proportion of the mass of the structural portion derived from another monomer can be controlled to a preferable range.

  Examples of the reactive functional group-containing monomer (C2) include (meth) acrylic acid ester monomers having a functional group such as a carboxyl group, a hydroxy group, an amino group, a substituted amino group, and an epoxy group, in addition to (meth) acrylic acid. Among them, (meth) acrylic acid is preferable.

  In the energy ray-curable antistatic polymer (C), the ratio of the mass of the structural portion derived from the reactive functional group-containing monomer (C2) to the total mass of the polymer (C) is 1 to 35% by mass. It is particularly preferably 3 to 20% by mass, and more preferably 3 to 10% by mass. When the mass ratio of the structural portion derived from the reactive functional group-containing monomer (C2) is within the above range, the energy ray-curable antistatic polymer of the energy ray-curable group based on the curable group-containing compound (C5) ( The amount introduced into C) can be controlled in a preferable range.

  When the energy ray-curable antistatic polymer (C) has a structural unit having an ether bond in a side chain, an ether bond-containing monomer (C3) is further used. As the ether bond-containing monomer (C3), a (meth) acrylate having an ether bond may be used. As the (meth) acrylate having an ether bond, for example, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, (2-methyl-2-ethyl) (Meth) acrylate having one structural unit having an ether bond, such as -1,3-dioxolan-4-yl) methyl (meth) acrylate and (3-ethyloxetane-3-yl) methyl (meth) acrylate; ethoxy; The repeating number of ethylene glycol units such as ethoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, and methoxypolyethylene glycol (meth) acrylate is 2 to 4. Ethylene glycol (meth) acrylate; propylene glycol (meth) acrylate in which the number of repeating propylene glycol units is 2 to 40; and the like, and one type alone or two or more types in combination. Can be used. Among these, repetition of alkylene glycol units such as ethylene glycol (meth) acrylate in which the number of repeating ethylene glycol units is 2 to 40, and propylene glycol (meth) acrylate in which the number of repeating propylene glycol units is 2 to 40 Alkylene glycol (meth) acrylate having a number of 2 to 40 is preferred, and ethylene glycol (meth) acrylate having a repeating number of ethylene glycol units of 2 to 40 is particularly preferred.

  In the energy ray-curable antistatic polymer (C), the ratio of the mass of the structural portion derived from the ether bond-containing monomer (C3) to the total mass of the polymer (C) is preferably 5 to 70% by mass. Preferably, it is particularly preferably from 10 to 50% by mass, and more preferably from 15 to 40% by mass. When the proportion of the mass of the structural portion derived from the ether bond-containing monomer (C3) is within the above range, the pressure-sensitive adhesive layer 3 can more easily obtain the effect of improving antistatic performance.

  The energy ray-curable antistatic polymer (C) preferably contains the other polymerizable monomer (C4), particularly an acrylic polymerizable monomer, as a monomer unit constituting the polymer (C). More preferably, it is contained. As such another polymerizable monomer (C4), a (meth) acrylate ester is preferably exemplified. The (meth) acrylic acid ester has, for example, a chain skeleton such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate ( (Meth) acrylate; having a cyclic skeleton such as cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, or imide acrylate ( (Meth) acrylate and the like. When the (meth) acrylate is an alkyl (meth) acrylate, the alkyl group preferably has 1 to 18 carbon atoms.

  As the curable group-containing compound (C5), those similar to the curable group-containing compound exemplified for the acrylic polymer (A3) can be exemplified. As the curable group-containing compound (C5), glycidyl (meth) acrylate, (meth) acryloyloxyethyl isocyanate and the like are preferable, and glycidyl (meth) acrylate is particularly preferable.

  Here, the curable group-containing compound (C5) and the reactive functional group-containing monomer (C2) are preferably reacted so that their molar equivalents are about equivalent.

  The weight average molecular weight of the energy ray-curable antistatic polymer (C) is preferably from 500 to 200,000, particularly preferably from 800 to 100,000, further preferably from 800 to 50,000. When the weight-average molecular weight of the energy ray-curable antistatic polymer (C) is 500 or more, the energy beam-curable antistatic polymer (C) can be obtained when the semiconductor processing sheet 1 according to the present embodiment is attached to an adherend. Bleed-out from the pressure-sensitive adhesive layer 3) can be effectively suppressed. In addition, when the weight average molecular weight of the energy ray-curable antistatic polymer (C) is 200,000 or less, there is no possibility that the adhesiveness of the adhesive layer 3 is adversely affected. Specifically, the molecular chain of the ionic energy ray-curable antistatic polymer (C) tends to spread, but this is suppressed, and the pressure-sensitive adhesive layer 3 exhibits good tackiness without becoming hard, The holding performance of the semiconductor wafer is maintained.

  In the present specification, the weight average molecular weight of the energy ray-curable antistatic polymer (C) is a value in terms of standard polymethyl methacrylate measured by a gel permeation chromatography (GPC) method. This will be described in an embodiment described later.

  The content of the energy ray-curable antistatic polymer (C) in the pressure-sensitive adhesive composition of the present embodiment is preferably 0.5 to 65% by mass, particularly preferably 10 to 50% by mass, and 13 More preferably, it is 30% by mass. When the compounding amount of the energy ray-curable antistatic polymer (C) is 0.5% by mass or more, the pressure-sensitive adhesive layer 3 is sufficiently imparted with antistatic properties. Further, when the amount of the energy ray-curable antistatic polymer (C) is 65% by mass or less, the cohesive force of the pressure-sensitive adhesive layer 3 before the energy ray irradiation is maintained high, and the pressure-sensitive adhesive layer 3 has preferable elasticity. As a result, the influence of vibration during dicing is suppressed, and the occurrence of chipping (chip chipping) is effectively suppressed.

  When the pressure-sensitive adhesive composition according to the present embodiment contains the above-described energy-ray-curable compound (A2), the pressure-sensitive adhesive composition according to the present embodiment includes an energy-ray-curable compound (A2) and an energy-ray-curable antistatic polymer. The total content of (C) is preferably from 10 to 75% by mass, particularly preferably from 15 to 60% by mass, and further preferably from 18 to 40% by mass. When the total content of the energy ray-curable compound (A2) and the energy ray-curable antistatic polymer (C) is 10% by mass or more, the pressure-sensitive adhesive layer 3 is sufficiently imparted with antistatic properties. When the total content is 75% by mass or less, the cohesive force of the pressure-sensitive adhesive layer 3 is maintained high, and the occurrence of chipping is effectively suppressed.

(4) Aspect of Compounding Each Component in Pressure-Sensitive Adhesive Composition In the present embodiment, the structural unit having an ether bond is an energy-curable compound (B) containing an ether bond or an energy-curable antistatic polymer (C) ) Is included in the pressure-sensitive adhesive composition.

  When the structural unit having an ether bond is contained in the pressure-sensitive adhesive composition as the energy bond-curable compound containing an ether bond (B), examples of such a pressure-sensitive adhesive composition include: an acrylic polymer (A1) and a resin having an ether bond. An energy ray-curable compound (A2), an energy ray-curable compound (B) (which also acts as an energy ray-curable compound (A2)) and an energy ray-curable antistatic polymer (C) Acrylic polymer (A1), ether bond-containing energy ray-curable compound (B) (which also acts as energy ray-curable compound (A2)), and energy ray-curable antistatic polymer (C) a pressure-sensitive adhesive composition; an acrylic polymer (A3) and an ether bond-containing energy ray-curable compound (B) ( Energy ray curable compound and also acts as (A2)), the pressure-sensitive adhesive composition containing an energy ray-curable antistatic polymer (C); and the like. The energy ray-curable antistatic polymer (C) may have a structural unit having an ether bond in a side chain.

  On the other hand, when a structural unit having an ether bond is included in the pressure-sensitive adhesive composition as a side chain of the energy ray-curable antistatic polymer (C), examples of such a pressure-sensitive adhesive composition include: an acrylic polymer (A1); An adhesive composition containing an energy ray-curable compound (A2) and an energy ray-curable antistatic polymer (C) having a structural unit having an ether bond in a side chain; an acrylic polymer (A3); A pressure-sensitive adhesive composition containing an energy ray-curable antistatic polymer (C) having a structural unit having a bond in a side chain; and the like. In addition, such a pressure-sensitive adhesive composition may further contain an ether bond-containing energy ray-curable compound (B).

(5) Crosslinking agent (D)
As described above, the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer 3 in the present embodiment may contain a crosslinking agent (D) that can react with the acrylic polymer (A1). In this case, the pressure-sensitive adhesive layer 3 in the present embodiment contains a crosslinked product obtained by a crosslinking reaction between the acrylic polymer (A1) and the crosslinking agent (D).

  Examples of the type of the crosslinking agent (D) include, for example, epoxy compounds, polyisocyanate compounds, metal chelate compounds, polyimine compounds such as aziridine compounds, melamine resins, urea resins, dialdehydes, methylol polymers, metal alkoxides, Metal salts and the like. Among these, an epoxy compound or a polyisocyanate compound is preferable because the crosslinking reaction is easily controlled.

  Examples of the epoxy compound include 1,3-bis (N, N′-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, ethylene glycol diglycidyl ether , 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidylaniline, diglycidylamine 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 diisocyanate, alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate, and the like. And an adduct 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 crosslinking agent (D) in the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer 3 is based on 100 parts by mass of the total amount of the energy ray-curable pressure-sensitive adhesive component (A) and the energy ray-curable antistatic polymer (C). , 0.01 to 50 parts by mass, more preferably 0.1 to 10 parts by mass.

  When the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer 3 in the present embodiment contains a crosslinking agent (D), it should contain an appropriate crosslinking accelerator according to the type of the crosslinking agent (D) and the like. Is preferred. For example, when the crosslinking agent (D) is a polyisocyanate compound, the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer 3 preferably contains an organometallic compound-based crosslinking accelerator such as an organotin compound.

(6) Other Components In addition to the above components, the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3 in the present embodiment includes various components such as a photopolymerization initiator, a coloring material such as a dye or a pigment, a flame retardant, and a filler. It may contain additives.

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

(7) Irradiation of energy rays The energy rays for curing the above-mentioned energy ray-curable pressure-sensitive adhesive component (A), ether bond-containing energy ray-curable compound (B) and energy ray-curable antistatic polymer (C) include And ionizing radiation, that is, X-rays, ultraviolet rays, and electron beams. Among these, ultraviolet rays, which are relatively easy to introduce irradiation equipment, are preferable.

When ultraviolet rays are used as ionizing radiation, near ultraviolet rays including ultraviolet rays having a wavelength of about 200 to 380 nm may be used from the viewpoint of easy handling. As the light amount, the type of the energy ray-curable group contained in the energy ray-curable pressure-sensitive adhesive component (A), the energy ray-curable compound (B) containing the ether bond and the energy ray-curable antistatic polymer (C), and the pressure-sensitive adhesive layer 3 It may be appropriately selected depending on the thickness of, usually 50 to 500 mJ / cm ² or so, preferably from 100~450mJ / cm ^2, and more preferably 200 to 400 mJ / cm ^2. The ultraviolet illumination is usually 50 to 500 mW / cm ² or so, preferably from ^{100~450mW / cm 2, 200~400mW / cm} 2 is more preferable. The ultraviolet light source is not particularly limited, and for example, a high-pressure mercury lamp, a metal halide lamp, a UV-LED, or the like is used.

  When an electron beam is used as the ionizing radiation, the accelerating voltage of the energy ray-curable pressure-sensitive adhesive component (A), the ether bond-containing energy ray-curable compound (B), and the energy ray-curable antistatic polymer (C) are increased. What is necessary is just to select suitably according to the kind of the energy-ray-curable group which has, and the thickness of the adhesive layer 3, and it is preferable that an acceleration voltage is usually about 10-1000 kV. The irradiation dose may be set in a range where the energy ray-curable adhesive component (A), the ether bond-containing energy ray-curable compound (B) and the energy ray-curable antistatic polymer (C) are appropriately cured, Usually, it is selected in the range of 10 to 1000 krad. The electron beam source is not particularly limited. For example, various electron beam accelerators such as Cockloft-Walton type, Van degraft type, resonance transformer type, insulating core transformer type, or linear type, dynamitron type, and high frequency type are used. be able to.

(8) Physical Properties, Shape, etc. (8-1) Thickness The thickness of the pressure-sensitive adhesive layer 3 in the present embodiment is 2 to 50 μm, preferably 5 to 30 μm, and particularly preferably 8 to 20 μm. When the thickness of the pressure-sensitive adhesive layer 3 is 20 μm or less, the amount of pressure-sensitive adhesive adhered matter generated when dicing an adherend such as a semiconductor wafer can be reduced, and the pressure-sensitive adhesive adhered substance becomes a chip or the like. Inconvenience caused by adhesion is unlikely to occur. On the other hand, when the thickness of the pressure-sensitive adhesive layer 3 is less than 2 μm, there is a possibility that the problem that the adhesiveness of the pressure-sensitive adhesive layer 3 varies greatly.

(8-2) Peeling voltage after energy ray curing The adhesive layer 3 in this embodiment is bonded to a silicon wafer, irradiated with energy rays, and then the silicon wafer and the pressure-sensitive adhesive layer 3 after energy ray curing are applied. Is preferably 0.6 kV or less, more preferably 0.4 kV or less, which is generated on the surface of the silicon wafer when is peeled off. preferable. Since the preferable antistatic property is obtained when the peeling voltage after energy beam curing is in the above range, when the semiconductor processing sheet 1 according to the present embodiment is peeled from the adherend, the adherend is peeled. Destruction due to charging can be prevented.

  In addition, the peeling electrification voltage here is obtained by cutting a semiconductor processing sheet into a width of 25 mm x a length of 200 mm, bonding an adhesive layer to a mirror surface of a silicon mirror wafer, and curing the adhesive layer 3 by irradiation with energy rays. This is the amount of charge generated on the wafer surface when the pressure-sensitive adhesive layer and the wafer are separated from each other, and the details of the measurement method will be described in Examples described later.

(8-3) Adhesive force In the semiconductor processing sheet 1 according to the present embodiment, the ratio of the adhesive force after irradiation with energy rays to the adhesive force before irradiation with energy rays is preferably 0.003 to 0.3. , 0.005 to 0.1, more preferably 0.008 to 0.05. When the ratio of the adhesive force is within the above range, the balance between the adhesive force before irradiation with the energy beam and the adhesive force after irradiation with the energy beam becomes good, and the sufficient adhesive force before irradiation with the energy beam and the irradiation with the energy beam are improved. It becomes easy to achieve a suitable adhesive strength later.

Here, the adhesive force is an adhesive force (mN / 25 mm) measured by a 180 ° peeling method according to JIS Z0237: 2009, using a silicon mirror wafer as an adherend, bonding a semiconductor processing sheet to the mirror surface of the silicon mirror wafer. ). In addition, the adhesive force after energy beam irradiation is determined by applying ultraviolet light (illuminance 230 mW / cm ²⁾ from the substrate 2 side of the semiconductor processing sheet 1 under a nitrogen atmosphere after the semiconductor processing sheet 1 is attached to an adherend. , Light intensity 190 mJ / cm ² ), and the measured value.

  The adhesive strength of the semiconductor processing sheet 1 before irradiation with energy rays is preferably 2,000 to 20,000 mN / 25 mm, more preferably 3,000 to 15,000 mN / 25 mm, and particularly preferably 3,500 to 10,000 mN / 25 mm. When the adhesive strength before the energy beam irradiation is within the above range, the adherend can be reliably fixed in the treatment step of the adherend.

  On the other hand, the adhesive force of the semiconductor processing sheet 1 after irradiation with energy rays is preferably 10 to 500 mN / 25 mm, more preferably 30 to 300 mN / 25 mm, and particularly preferably 50 to 200 mN / 25 mm. preferable. When the adhesive force after the energy ray irradiation is within the above range, the adherend can be easily peeled from the semiconductor processing sheet 1 at the time of peeling, and the cohesive failure of the adhesive layer 3 at the time of peeling can be achieved. In addition, contamination of the adherend by particles can be suppressed.

  The pressure-sensitive adhesive layer 3 in the present embodiment is formed from the above-described pressure-sensitive adhesive composition, so that the pressure-sensitive adhesive force of the semiconductor processing sheet 1 before the energy beam irradiation, the pressure-sensitive adhesive force after the energy beam irradiation, and the ratio thereof are set as described above. It is easy to control within the range.

(8-4) Release Sheet The sheet 1 for semiconductor processing according to the present embodiment is provided with the base of the adhesive layer 3 for the purpose of protecting the adhesive layer 3 until the adhesive layer 3 is attached to the adherend. A release sheet may be laminated on a surface opposite to the surface on the material 2 side. The configuration of the release sheet is arbitrary, and examples thereof include those obtained by subjecting a plastic film to a release treatment 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-based, fluorine-based, long-chain alkyl-based, or the like can be used, and among these, a silicone-based, which is inexpensive and provides stable performance, is preferable. The thickness of the release sheet is not particularly limited, but is usually about 20 to 250 μm.

3. Method of Manufacturing Sheet for Semiconductor Processing The method of manufacturing the sheet for semiconductor processing 1 is not particularly limited as long as the pressure-sensitive adhesive layer 3 formed from the above-described pressure-sensitive adhesive composition can be laminated on one surface of the substrate 2. . For example, a coating composition containing the above-described pressure-sensitive adhesive composition and, if desired, a solvent or a dispersion medium is prepared, and a die coater, a curtain coater, a spray coater is formed on one surface of the substrate 2. The pressure-sensitive adhesive layer 3 can be formed by applying the coating composition with a slit coater, a knife coater or the like to form a coating film, and drying the coating film. The properties of the coating composition are not particularly limited as long as the composition can be applied, and may include a component for forming the pressure-sensitive adhesive layer 3 as a solute or a dispersoid. There is also.

  When the coating composition contains a cross-linking agent (D), the acrylic weight in the coating film is changed by changing the above-mentioned drying conditions (temperature, time, etc.) or by separately providing a heat treatment. The cross-linking reaction between the union (A1) or (A3) and the cross-linking agent (D) may be advanced to form a cross-linked structure at a desired density in the pressure-sensitive adhesive layer 3. After the pressure-sensitive adhesive layer 3 is laminated on the substrate 2 by the above-described method or the like in order to allow the crosslinking reaction to sufficiently proceed, the obtained semiconductor processing sheet 1 is placed in an environment of, for example, 23 ° C. and 50% relative humidity. Curing is usually carried out, such as allowing to stand for several days.

  As another example of the method of manufacturing the semiconductor processing sheet 1, a coating composition is applied on the release surface of the release sheet to form a coating film, which is dried to form the adhesive layer 3 and the release sheet. Is formed, and the surface of the pressure-sensitive adhesive layer 3 of the laminate opposite to the surface on the release sheet side is affixed to the substrate 2 to form a laminate of the semiconductor processing sheet 1 and the release sheet. You may get it. The release sheet in the laminate may be peeled off as a process material, or the adhesive layer 3 may be protected until the release sheet is attached to an adherend such as a semiconductor wafer.

4. Method for Manufacturing Chip A method for manufacturing a chip from a semiconductor wafer using the semiconductor processing sheet 1 according to the present embodiment will be described below as an example.

  In using the semiconductor processing sheet 1 according to the present embodiment, a surface on the side of the pressure-sensitive adhesive layer 3 (that is, a surface of the pressure-sensitive adhesive layer 3 on a side opposite to the base material 2) is attached to a semiconductor wafer. When a release sheet is laminated on the surface of the semiconductor processing sheet 1 on the pressure-sensitive adhesive layer 3 side, the release sheet is peeled off to expose the surface on the pressure-sensitive adhesive layer 3 side, and to attach a semiconductor wafer. The surface may be attached to the surface. The peripheral portion of the semiconductor processing sheet 1 is usually attached to an annular jig called a ring frame for transporting and fixing to a device by an adhesive layer 3 provided on the peripheral portion.

  Next, a dicing step is performed to obtain a plurality of chips from the semiconductor wafer. The pressure-sensitive adhesive layer 3 of the semiconductor processing sheet 1 is formed by adjusting the content of each component of the pressure-sensitive adhesive composition forming the same (for example, the energy-ray-curable antistatic polymer (C) in the pressure-sensitive adhesive composition). For example, the content is set to 65% by mass or less), the cohesiveness before energy beam irradiation is maintained at a high level, and the dicing step has favorable elasticity. Therefore, by using the semiconductor processing sheet 1 according to the present embodiment, the influence of vibration during the dicing step is suppressed, and the occurrence of chipping is suppressed.

  After the dicing step, energy beam irradiation is performed from the substrate 2 side of the semiconductor processing sheet 1. Thereby, the energy beam-curable adhesive component (A), the energy beam-curable compound (B) and the energy beam-curable antistatic polymer (C) contained in the energy beam-curable antistatic polymer (C) contained in the pressure-sensitive adhesive layer 3 are included. As the polymerization reaction proceeds, the tackiness decreases, and the chip can be picked up.

  As an example, after the energy beam irradiation, an expanding step of extending the semiconductor processing sheet 1 in a planar direction is performed so that a plurality of chips arranged close to the semiconductor processing sheet 1 can be easily picked up. The degree of the elongation may be appropriately set in consideration of the interval that the chips arranged close to each other should have, the tensile strength of the base material 2, and the like. In addition, the expanding step may be performed before the energy beam irradiation.

  After the expanding step, the chips on the adhesive layer 3 are picked up. The pickup is performed by a general-purpose means such as a suction collet. At this time, in order to facilitate the pickup, it is preferable to push up the target chip from the substrate 2 side of the semiconductor processing sheet 1 with a pin or a needle. .

  In the semiconductor processing sheet 1 according to the present embodiment, a force required for pickup when picking up a chip obtained by dicing to 5 mm × 5 mm with a push-up pin (hereinafter, may be referred to as “5 mm □ pickup force”). Is preferably 2N or less, particularly preferably 1.8N or less. In the semiconductor processing sheet 1 according to the present embodiment, since the pressure-sensitive adhesive layer 3 is formed from the above-described pressure-sensitive adhesive composition, it is easy to control the 5 mm square pickup force within the above range. The lower limit of the 5 mm square pick-up force is preferably 0.5 N or more, and more preferably 0.8 N or more, from the viewpoint of preventing the chip from unintentionally peeling off from the semiconductor processing sheet 1. Is particularly preferred.

  Here, the 5 mm □ pick-up force in this specification means that a 100 μm-thick silicon wafer is diced into 5 mm × 5 mm, irradiated with energy rays, and picked up into individual chips (thrust pins: 1 pin). , Push-up speed: 1 mm / sec) is a value measured by a push-pull gauge (AIKOH ENGINEERING, RX-1) as the force (N) required for the pickup. Details of the measurement method are described later in Examples. Indicated by

  In the sheet 1 for semiconductor processing according to the present embodiment, since the energy ray-curable antistatic polymer (C) contained in the pressure-sensitive adhesive layer 3 has a salt (cation), generation of peeling charge at the time of peeling of a pickup or the like is prevented. Thus, the chip can be collected without breaking the circuit or the chip. Further, since the energy ray-curable antistatic polymer (C) contained in the pressure-sensitive adhesive layer 3 has an energy ray-curable group, the chip is less likely to be contaminated. Note that the picked-up chip is provided to the next step such as a transport step.

  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 interposed between the base material 2 and the pressure-sensitive adhesive layer 3 in the semiconductor processing sheet 1.

  Hereinafter, the present invention will be described more specifically 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 85 parts by mass of n-butyl acrylate and 15 parts by mass of 2-hydroxyethyl acrylate were copolymerized to prepare an acrylic polymer (A1). When the molecular weight of this acrylic polymer (A1) was measured by the method described later, the weight average molecular weight was 600,000. The obtained acrylic polymer (A1) was diluted with a mixed solvent of toluene and ethyl acetate to a solid concentration of 34% by mass.

(2) Preparation of energy ray-curable antistatic polymer (C) [2- (methacryloyloxy) ethyl] trimethylammonium bis (trifluoromethylsulfonyl) imide as quaternary ammonium salt monomer (C1), containing a reactive functional group A methacrylic acid as the monomer (C2) and 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate as the polymerizable monomer (C4) were prepared by mixing a quaternary ammonium salt monomer (C1) with a molar ratio of methacrylic acid (C2): Copolymerization was performed so that 2-ethylhexyl acrylate (C4): 2-hydroxyethyl acrylate (C4) = 0.027: 0.015: 0.052: 0.011. The obtained polymer is reacted with glycidyl methacrylate (0.012 in terms of the above molar ratio) as a curable group-containing compound (C5), and the energy ray-curable antistatic polymer (C) (in the side chain) Having a methacryloyl group and a quaternary ammonium salt). When the molecular weight of this energy ray-curable antistatic polymer (C) was measured by the method described later, the weight average molecular weight was 170,000.

(3) Preparation of Sheet for Semiconductor Processing 100 parts by mass of the acrylic copolymer (A1) obtained in the above step (1) (in terms of solid content; hereinafter similarly described), as the energy ray-curable compound (A2) 45 parts by mass of a 6-functional urethane acrylate (weight average molecular weight: 2000), 25 parts by mass of tetraethylene glycol diacrylate as an ether bond-containing energy ray-curable compound (B), energy ray curing obtained in the above step (2) 16 parts by mass of a hydrophilic antistatic polymer (C), 3.0 parts by mass of 1-hydroxycyclohexylphenyl ketone (IRGACURE 184, manufactured by BASF) as a photopolymerization initiator, and a tolylene diisocyanate compound (D) as a crosslinking agent (D) 1.4 parts by mass of Toyo Ink Co., Ltd., BHS-8515) were mixed and thoroughly stirred. By diluting with ketone, a coating solution of the pressure-sensitive adhesive composition was obtained.

  The obtained coating solution of the pressure-sensitive adhesive composition was coated on a release surface of a release sheet (manufactured by Lintec, SP-PET381031, thickness: 38 μm) in which one surface of a polyethylene terephthalate film was release-treated with a silicone-based release agent. And then treated at 80 ° C. for 1 minute to form a coating film of the pressure-sensitive adhesive composition. The thickness of the obtained coating film after drying was 10 μm. Next, by laminating the obtained coating film and an ethylene-methacrylic acid copolymer (EMAA) film (thickness: 80 μm) as a substrate, the surface of the pressure-sensitive adhesive layer on the side of the substrate is opposite. With the release sheet laminated on the side surface, a semiconductor processing sheet was obtained.

[Example 2]
[2- (methacryloyloxy) ethyl] trimethylammonium bis (trifluoromethylsulfonyl) imide as a quaternary ammonium salt monomer (C1), methacrylic acid as a reactive functional group-containing monomer (C2), and an ether bond-containing monomer (C3 )) And 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate as polymerizable monomers (C4) as quaternary ammonium salt monomers (C1): Methacrylic acid (C2): Ether bond-containing monomer (C3): 2-ethylhexyl acrylate (C4): 2-hydroxyethyl acrylate (C4) = 0.027: 0.015: 0.037: 0.011: 0 .011 Copolymerized as described above. The obtained polymer is reacted with glycidyl methacrylate (0.012 in terms of the above molar ratio) as a curable group-containing compound (C5), and the energy ray-curable antistatic polymer (C) (in the side chain) (Having a methacryloyl group, a quaternary ammonium salt and an ethylene glycol unit). When the molecular weight of the energy ray-curable antistatic polymer (C) was measured by the method described later, the weight average molecular weight was 200,000.

  100 parts by mass of the acrylic copolymer (A1) obtained in Example 1, 45 parts by mass of a hexafunctional urethane acrylate (weight average molecular weight: 2000) as an energy ray-curable compound (A2), produced in this example. 16 parts by mass of an energy ray-curable antistatic polymer (C), 3.0 parts by mass of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, manufactured by BASF) as a photopolymerization initiator, and tolylene as a crosslinking agent (D) 1.4 parts by mass of an isocyanate compound (manufactured by Toyo Ink Co., Ltd., BHS-8515) was mixed, sufficiently stirred, and diluted with methyl ethyl ketone to obtain a coating solution of the pressure-sensitive adhesive composition. Using the coating solution of the obtained pressure-sensitive adhesive composition, a sheet for semiconductor processing was manufactured in the same manner as in Example 1.

[Example 3]
An acrylic polymer was prepared by copolymerizing 85 parts by mass of n-butyl acrylate and 15 parts by mass of 2-hydroxyethyl acrylate. When the molecular weight of this acrylic polymer was measured by the method described later, the weight average molecular weight was 500,000. The obtained acrylic polymer was reacted with methacryloyloxyethyl acrylate in an amount of 80 mol% of 2-hydroxyethyl acrylate, and an acrylic polymer (A3) having an energy-ray-curable group introduced into a side chain. ) Got.

  100 parts by mass of the obtained acrylic copolymer (A3), 25 parts by mass of tetraethylene glycol diacrylate as the ether bond-containing energy ray-curable compound (B), the energy ray-curable antistatic obtained in Example 1 16 parts by mass of the polymer (C), 3.0 parts by mass of 1-hydroxycyclohexylphenyl ketone (IRGACURE 184, manufactured by BASF) as a photopolymerization initiator, and a tolylene diisocyanate compound (Toyo Ink Co., Ltd.) as a crosslinking agent (D) (BHS-8515), 1.4 parts by mass, mixed sufficiently, and diluted with methyl ethyl ketone to obtain a coating solution of the pressure-sensitive adhesive composition. Using the coating solution of the obtained pressure-sensitive adhesive composition, a sheet for semiconductor processing was manufactured in the same manner as in Example 1.

[Example 4]
100 parts by mass of the acrylic copolymer (A3) obtained in Example 3, 16 parts by mass of the energy ray-curable antistatic polymer (C) obtained in Example 2, 1-hydroxycyclohexyl as a photopolymerization initiator 3.0 parts by mass of phenyl ketone (Irgacure 184, manufactured by BASF) and 1.4 parts by mass of a tolylene diisocyanate compound (BHS-8515, manufactured by Toyo Ink Co., Ltd.) as a crosslinking agent (D) were mixed and sufficiently stirred. Then, by diluting with methyl ethyl ketone, a coating solution of the pressure-sensitive adhesive composition was obtained. Using the coating solution of the obtained pressure-sensitive adhesive composition, a sheet for semiconductor processing was manufactured in the same manner as in Example 1.

[Comparative Example 1]
As in Example 1, the molar ratio was quaternary ammonium salt monomer (C1): methacrylic acid (C2): 2-ethylhexyl acrylate (C4): 2-hydroxyethyl acrylate (C4) = 0.027: 0. 015: 0.052: 0.011 to obtain an antistatic polymer (having a quaternary ammonium salt in a side chain) without reacting glycidyl methacrylate. When the molecular weight of this antistatic polymer was measured by the method described later, the weight average molecular weight was 190,000.

  100 parts by mass of the acrylic copolymer (A1) obtained in Example 1, 45 parts by mass of a hexafunctional urethane acrylate (weight average molecular weight: 2000) as an energy ray-curable compound (A2), produced in this comparative example 16 parts by mass of an antistatic polymer, 3.0 parts by mass of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, manufactured by BASF) as a photopolymerization initiator, and a tolylene diisocyanate compound (manufactured by Toyo Ink Co., Ltd.) as a crosslinking agent (D) , BHS-8515), 1.4 parts by mass, mixed sufficiently, and diluted with methyl ethyl ketone to obtain a coating solution of the pressure-sensitive adhesive composition. Using the coating solution of the obtained pressure-sensitive adhesive composition, a sheet for semiconductor processing was manufactured in the same manner as in Example 1.

[Reference Example 1]
An acrylic polymer (A1) was obtained by copolymerizing 25 parts by mass of n-butyl acrylate, 65 parts by mass of ethoxyethoxyethyl acrylate (having two ethylene oxide units), and 15 parts by mass of 2-hydroxyethyl acrylate. ) Was prepared. When the molecular weight of this acrylic polymer (A1) was measured by the method described later, the weight average molecular weight was 500,000.

  100 parts by mass of the acrylic copolymer (A1) obtained in the present reference example, 45 parts by mass of a hexafunctional urethane acrylate (weight average molecular weight: 2000) as the energy ray-curable compound (A2), obtained in Example 1. Energy-curable antistatic polymer (C) 16 parts by mass, 1-hydroxycyclohexyl phenyl ketone (BASF Co., Irgacure 184) 3.0 parts by mass as a photopolymerization initiator, and tri as a crosslinking agent (D) 1.4 parts by mass of a range isocyanate compound (manufactured by Toyo Ink Co., Ltd., BHS-8515) was mixed, sufficiently stirred, and diluted with methyl ethyl ketone to obtain a coating solution of the pressure-sensitive adhesive composition. Using the coating solution of the obtained pressure-sensitive adhesive composition, a sheet for semiconductor processing was manufactured in the same manner as in Example 1.

[Reference Example 2]
A semiconductor processing sheet was manufactured in the same manner as in Example 1 except that tetraethylene glycol diacrylate was not used in the above step (3).

  Here, the weight average molecular weight (Mw) of the above-mentioned acrylic copolymers (A1) and (A3) is measured by gel permeation chromatography (GPC) (GPC measurement) and is a weight average molecular weight in terms of standard polystyrene. The weight average molecular weight (Mw) of the energy ray-curable antistatic polymer (C) is a weight average molecular weight in terms of standard polymethyl methacrylate measured by GPC. The conditions of each GPC measurement are shown below.

<GPC measurement conditions of acrylic copolymers (A1) and (A3)>
・ Column: TSKgelGMHXL (2), TSKgel2000HXL connected in this order ・ Solvent: THF
・ Measurement temperature: 40 ° C
・ Flow rate: 1 ml / min ・ Detector: Differential refractometer ・ Standard sample: polystyrene

<GPC measurement conditions of energy ray-curable antistatic polymer (C)>
-Column: Shodex HFIP-LG, HFIP-806M (two) connected in this order-Solvent: Hexafluoroisopropanol (5 mM sodium trifluoroacetate added)
・ Measurement temperature: 40 ° C
・ Flow rate: 0.5 ml / min ・ Detector: Differential refractometer ・ Standard sample: polymethyl methacrylate

[Test Example 1] (Measurement of peeling voltage)
The semiconductor processing sheets manufactured in Examples and Comparative Examples were cut into a width of 25 mm and a length of 200 mm, and this was used as a sample. The release sheet was peeled off from the sample, the pressure-sensitive adhesive layer was bonded to the mirror surface of the silicon wafer, and pressed and laminated by reciprocating a 1 kg roller once. After storing this at 23 ° C. and 50% relative humidity for 20 minutes, the sample was irradiated with ultraviolet (UV) light (illuminance: 230 mW / cm ² , light amount: 190 mJ / cm ² ) from the substrate side. The sample was peeled off from the laminate of the sample and the silicon wafer after the ultraviolet irradiation by an autograph (manufactured by Shimadzu Corporation) so that the peeling speed was 300 mm / min and the peeling angle was 180 °. The amount of charge generated on the wafer surface at this time was measured with a charged voltage meter (PROSTAT, PFM-711A) fixed at a position 1 cm from the sample peeling portion. Table 1 shows the results.

[Test Example 2] (Evaluation of wafer contamination)
The release sheet was peeled off from the semiconductor processing sheets produced in the examples and comparative examples, the adhesive layer was stuck on a silicon wafer, and a 5 kg roller was reciprocated once to laminate by applying a load. This was allowed to stand at 23 ° C. and 50% relative humidity for 24 hours, and then ultraviolet (UV) irradiation (illuminance: 230 mW / cm ² , light amount: 190 mJ / cm ² ) was performed from the substrate side of the semiconductor processing sheet. Was. After peeling the semiconductor processing sheet from the laminated body of the semiconductor processing sheet and the silicon wafer after the ultraviolet irradiation at a peeling speed of 300 mm / min and a peeling angle of 180 °, a wafer surface inspection device (Hitachi Engineering Co., S6600) Was used to measure the number of residues (particles) having a maximum diameter of 0.27 μm or more on the silicon wafer. Table 1 shows the results.

[Test Example 3] (Evaluation of 5 mm pick-up force)
The release sheet was peeled off from the semiconductor processing sheet manufactured in each of Examples and Comparative Examples, and a 6-inch silicon wafer (thickness: 8 mm) was formed on the exposed adhesive layer using a tape mounter (manufactured by Lintec Corporation, RAD 2500 m / 8). 100 μm) and a ring frame for dicing. Subsequently, after cutting the semiconductor processing sheet according to the outer diameter of the ring frame, dicing for cutting from the silicon wafer side under the following dicing conditions is performed using a dicing apparatus (manufactured by Disco: DFD-651). A 5 mm × 5 mm chip was obtained.

<Dicing conditions>
・ Wafer thickness: 100 μm
・ Dicing device: DFD-651 manufactured by Disco
・ Blade: NBC-ZH2050 27HECC manufactured by Disco
-Blade width: 0.025 to 0.030 mm
・ Cutting edge: 0.640 to 0.760 mm
-Blade rotation speed: 30,000 rpm
・ Cutting speed: 50mm / sec
・ Base material cutting depth: 20 μm
・ Cutting water volume: 1.0L / min
・ Cutting water temperature: 20 ℃

After the dicing, the substrate was allowed to stand at 23 ° C. and 50% relative humidity for 24 hours, and then irradiated with ultraviolet (UV) light (illuminance) from the substrate side of the semiconductor processing sheet using an ultraviolet irradiation device (manufactured by Lintec, RAD2000m / 8). : 230 mW / cm ² , light intensity: 190 mJ / cm ² , nitrogen purge: present (flow rate: 30 L / min). After irradiation with ultraviolet rays, an expanding step (expanding amount: 5 mm withdrawal) was performed, and the chip was picked up under the following conditions. At this time, the force (N) required for the pickup was measured by a push-pull gauge (manufactured by AIKOH ENGINEERING, RX-1), and the average value of the measured values for 20 chips was calculated. Table 1 shows the results.

<Pickup conditions>
・ Chip size: 5mm x 5mm
-Number of pins: 1-Push-up speed: 1 mm / sec

  As is clear from Table 1, the semiconductor processing sheet of the example had a sufficiently small peeling voltage and was excellent in antistatic properties, and had few particles on the wafer to suppress contamination. Further, in Examples 1 to 4, chips could be picked up with a smaller pickup force than in Reference Example 1, and the adhesive strength before irradiation with ultraviolet rays was large. Further, in Examples 1 to 4, the peeling electrostatic voltage was smaller than that in Reference Example 2.

  The semiconductor processing sheet according to the present invention is particularly suitably used in a manufacturing process of a semiconductor wafer or a chip in which peeling charging may be a problem.

DESCRIPTION OF SYMBOLS 1 ... Semiconductor processing sheet 2 ... Substrate 3 ... Adhesive layer

Claims (11)

A semiconductor processing sheet comprising a base material and an adhesive layer laminated on at least one surface of the base material,
The pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing a salt and a polymer having an energy-ray-curable group, and an energy-ray-curable pressure-sensitive adhesive component different from the polymer.
The pressure-sensitive adhesive composition contains a structural unit having an ether bond and a compound having an energy-ray-curable group as one component of an energy-ray-curable pressure-sensitive adhesive component, or has an ether bond as a side chain of the polymer. A semiconductor processing sheet having a unit.   The semiconductor processing sheet according to claim 1, wherein the constituent unit having an ether bond is an alkylene oxide unit.   3. The semiconductor processing sheet according to claim 2, wherein the alkylene oxide unit is a repeating unit of 2 to 40. 4.   The semiconductor processing sheet according to any one of claims 1 to 3, wherein the content of the polymer in the pressure-sensitive adhesive composition is 0.5 to 65% by mass.   The semiconductor processing sheet according to any one of claims 1 to 4, wherein the polymer has a weight average molecular weight of 500 to 200,000.   6. The semiconductor processing sheet according to claim 1, wherein the polymer has a (meth) acryloyl group as the energy ray-curable group. 7. The content of the energy ray-curable group per unit mass of the polymer is 5 × 10 ⁻⁵ to 2 × 10 ⁻³ mol / g, according to any one of claims 1 to 6, wherein The semiconductor processing sheet according to the above.   The semiconductor device according to any one of claims 1 to 7, wherein the energy ray-curable adhesive component contains an acrylic polymer having no energy ray curability and an energy ray-curable compound. Sheet.   The sheet for semiconductor processing according to any one of claims 1 to 7, wherein the energy ray-curable adhesive component contains an acrylic polymer having an energy ray-curable group introduced into a side chain. .   The semiconductor processing sheet according to any one of claims 1 to 9, wherein the energy ray-curable pressure-sensitive adhesive component contains a crosslinking agent.   The semiconductor processing sheet according to any one of claims 1 to 10, wherein the salt is a quaternary ammonium salt.

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