Pressure-sensitive adhesive sheet for workpiece processing

Abstract

To provide a pressure-sensitive adhesive sheet for workpiece processing in which occurrence of separation of a base material and an adhesive layer having energy ray-curability is suppressed, and occurrence of adhesive residue on a workpiece is suppressed.SOLUTION: A pressure-sensitive adhesive sheet for workpiece processing 100 comprises a base material 10, a first adhesive layer 21 disposed on at least one surface of the base material 10 and having energy ray-curability, and a second adhesive layer 22 disposed between the base material 10 and the first adhesive layer 21 and having no energy ray-curability. The first adhesive layer 21 contains an adhesive having energy ray-curability, the second adhesive layer 22 contains a non-energy ray curable adhesive having no energy ray-curability. An absolute value of a difference between a polarity value of the non-energy ray curable adhesive and a polarity value of the energy ray curable adhesive is 1.00(cal / cm3)0.5 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an adhesive sheet for workpiece processing. [Background technology]

[0002] For example, semiconductor devices are manufactured through various processes such as a backgrinding process, a dicing process, an expanding process, a transfer process, and a pick-up process. Specifically, for example, a semiconductor wafer is cut into a predetermined shape and size and singulated into a plurality of semiconductor chips. The singulated chips are then mounted on a mounting object such as a lead frame or a substrate after the spacing between each chip is increased. In the manufacturing process of a semiconductor device, workpieces such as semiconductor wafers and semiconductor packages are subjected to various processes in each of the above processes while being attached to an adhesive layer of an adhesive sheet for workpiece processing, which has an adhesive layer provided on a base material.

[0003] Also, for example, a transparent member such as a glass substrate or glass plate is processed using a workpiece processing adhesive sheet having a base material and an adhesive layer. For example, the transparent member is attached to the adhesive layer of the workpiece processing adhesive sheet, and the sheet is cut into a predetermined shape and size to be separated into a plurality of chip-shaped transparent members (for example, glass chips).

[0004] Patent Document 1 discloses a workpiece processing sheet comprising a substrate and an adhesive layer laminated on one side of the substrate. The workpiece processing sheet disclosed in Patent Document 1 has a static friction force of 10 N or less on the surface of the substrate opposite to the adhesive layer, a tensile modulus of E1 when the substrate is stretched by 1% in a tensile test at 23°C, and a tensile modulus of E2 when the substrate is stretched by 20% in a tensile test at 23°C. 20 When E 20 The tensile modulus ratio calculated by / E1 is 0.25 or more when the static friction force is 1 to 10 N, and is 0.03 or more when the static friction force is less than 1 N. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-151238 Summary of the Invention [Problem to be solved by the invention]

[0006] The adhesive sheet for workpiece processing, which includes a substrate and an adhesive layer provided on the substrate, is used for various processing of the workpiece. After the workpiece is subjected to various processing while attached to the adhesive layer of the adhesive sheet for workpiece processing, the workpiece is peeled off from the adhesive layer of the adhesive sheet for workpiece processing.

[0007] When a workpiece processing adhesive sheet including a substrate and an energy ray-curable adhesive layer provided on the substrate is used for various processing of a workpiece, the energy ray-curable adhesive layer is irradiated with energy rays, and then the workpiece is peeled off from the adhesive layer of the workpiece processing adhesive sheet. When the workpiece is peeled off from the adhesive layer of the workpiece processing adhesive sheet, the adhesive layer and the substrate may separate at the interface between the substrate and the energy ray-curable adhesive layer, causing the adhesive layer to peel off from the substrate. If the adhesive layer peels off from the substrate at the interface between the adhesive layer and the substrate, the adhesive layer remains attached to the workpiece. Even if the adhesive layer and the substrate do not separate at the interface between the substrate and the energy ray-curable adhesive layer, at least a portion of the adhesive layer attached to the workpiece may remain on the workpiece, resulting in so-called adhesive residue.

[0008] An object of the present invention is to provide an adhesive sheet for workpiece processing that suppresses peeling between the substrate and the energy ray-curable adhesive layer and also suppresses the occurrence of adhesive residue on the workpiece. [Means for solving the problem]

[0009] [1] An adhesive sheet for workpiece processing, A substrate; a first pressure-sensitive adhesive layer having energy ray curability and provided on at least one surface of the substrate; a second pressure-sensitive adhesive layer that is not energy ray-curable and is provided between the substrate and the first pressure-sensitive adhesive layer; Equipped with the first pressure-sensitive adhesive layer contains an energy ray-curable pressure-sensitive adhesive, the second pressure-sensitive adhesive layer contains a non-energy ray-curable pressure-sensitive adhesive that does not have energy ray-curability, The absolute value of the difference between the polarity value of the non-energy ray curable adhesive and the polarity value of the energy ray curable adhesive is 1.00 (cal / cm 3 ) 0.5 Below is the Adhesive sheet for workpiece processing.

[0010] [2] In the adhesive sheet for workpiece processing according to [1], The polarity of the non-energy ray curable adhesive is 9.80 (cal / cm 3 ) 0.5 That's all. Adhesive sheet for workpiece processing.

[0011] [3] In the adhesive sheet for workpiece processing according to [1] or [2], the polarity of the energy ray-curable adhesive is greater than the polarity of the non-energy ray-curable adhesive; Adhesive sheet for workpiece processing.

[0012] [4] The adhesive sheet for workpiece processing according to any one of [1] to [3], The adhesive sheet for work processing is an adhesive sheet for semiconductor package processing. Adhesive sheet for workpiece processing.

[0013] [5] The adhesive sheet for workpiece processing according to any one of [1] to [4], The adhesive sheet for workpiece processing is a dicing sheet. Adhesive sheet for workpiece processing.

[0014] [6] The adhesive sheet for workpiece processing according to any one of [1] to [5], The non-energy ray curable pressure-sensitive adhesive is an acrylic pressure-sensitive adhesive. Adhesive sheet for workpiece processing.

[0015] [7] In the adhesive sheet for workpiece processing according to [6], The non-energy ray curable pressure-sensitive adhesive contains a (meth)acrylic copolymer containing a structural unit derived from n-butyl acrylate in the largest amount. Adhesive sheet for workpiece processing.

[0016] [8] In the adhesive sheet for workpiece processing according to [7], The (meth)acrylic copolymer further contains a structural unit derived from acrylic acid. Adhesive sheet for workpiece processing.

[0017] [9] The adhesive sheet for workpiece processing according to any one of [1] to [8], The energy ray-curable pressure-sensitive adhesive is an acrylic pressure-sensitive adhesive. Adhesive sheet for workpiece processing.

[0018]

[10] In the adhesive sheet for workpiece processing according to [9], The acrylic pressure-sensitive adhesive is a (meth)acrylic acid ester polymer having an energy ray-curable group introduced into a side chain, and contains a (meth)acrylic acid ester copolymer containing a structural unit derived from n-butyl acrylate in the largest amount. Adhesive sheet for workpiece processing. [Effects of the Invention]

[0019] According to one aspect of the present invention, an adhesive sheet for workpiece processing can be provided in which peeling between the substrate and the energy ray-curable adhesive layer is suppressed and adhesive residue on the workpiece is suppressed. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic cross-sectional view illustrating an example of an adhesive sheet for workpiece processing according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] A preferred embodiment of the present invention will be described below by way of example, but the present invention is not limited to the content of the embodiment.

[0022] [Adhesive sheet for workpiece processing] The adhesive sheet for workpiece processing according to this embodiment comprises a substrate, a first adhesive layer having energy ray curability provided on at least one surface of the substrate, and a second adhesive layer not having energy ray curability provided between the substrate and the first adhesive layer. The first adhesive layer contains an adhesive having energy ray curability, and the second adhesive layer contains a non-energy ray curable adhesive not having energy ray curability. The absolute value of the difference between the polarity value of the non-energy ray curable adhesive and the polarity value of the energy ray curable adhesive is 1.00 (cal / cm 3 ) 0.5 The following is the result.

[0023] In this specification, "energy ray curable" means a property of being cured by irradiation with energy rays, and "non-energy ray curable" means a property of not being cured even when irradiated with energy rays. Examples of energy rays include ultraviolet rays and electron beams.

[0024] The adhesive sheet for workpiece processing according to the present embodiment will be described below with reference to the drawings. Fig. 1 shows a schematic cross-sectional view of an example of the adhesive sheet for workpiece processing according to the present embodiment. Note that some parts of the drawings are enlarged or reduced in size to facilitate explanation.

[0025] As shown in FIG. 1 , the adhesive sheet 100 for workpiece processing includes a substrate 10, a first adhesive layer 21, and a second adhesive layer 22 disposed between the substrate 10 and the first adhesive layer 21. The second adhesive layer 22 is an intermediate layer. The substrate 10 includes a first main surface 10A and a second main surface 10B opposite the first main surface 10A. In the adhesive sheet 100 for workpiece processing, the first main surface 10A of the substrate 10 is the surface disposed on the side of the first adhesive layer 21 and the second adhesive layer 22, and the second main surface 10B of the substrate 10 is the outer surface of the substrate 10. The second adhesive layer 22 includes a first main surface 22A and a second main surface 22B opposite the first main surface 22A. The second adhesive layer 22 is provided in direct contact with the substrate 10, and the first main surface 10A of the substrate 10 faces the second main surface 22B of the second adhesive layer 22. The first pressure-sensitive adhesive layer 21 has a first main surface 21A and a second main surface 21B opposite to the first main surface 21A. The first pressure-sensitive adhesive layer 21 is provided in direct contact with the second pressure-sensitive adhesive layer 22, and the first main surface 22A of the second pressure-sensitive adhesive layer 22 faces the second main surface 21B of the first pressure-sensitive adhesive layer 21. The first main surface 21A of the first pressure-sensitive adhesive layer 21 is an adhesive surface. Here, the main surface refers to the largest surface in each of the substrate 10, the first pressure-sensitive adhesive layer 21, and the second pressure-sensitive adhesive layer 22, and is the surface facing in the thickness direction (i.e., the stacking direction of the layers).

[0026] In the adhesive sheet 100 for workpiece processing, the first adhesive layer 21 has energy ray curability. The first adhesive layer 21 contains an adhesive that has energy ray curability. The second adhesive layer 22 does not have energy ray curability. The second adhesive layer 22 contains a non-energy ray curable adhesive that does not have energy ray curability. The absolute value of the difference between the polarity value of the non-energy ray curable adhesive contained in the second adhesive layer 22 and the polarity value of the energy ray curable adhesive contained in the first adhesive layer 21 is 1.00 (cal / cm 3 ) 0.5 The following is the result.

[0027] The adhesive sheet 100 for workpiece processing, having the above-described configuration, suppresses peeling between the substrate 10 and the first adhesive layer 21, which is an energy ray-curable adhesive layer, and also suppresses the occurrence of adhesive residue on the workpiece when the adhesive sheet 100 for workpiece processing is peeled from the workpiece (not shown) after the energy ray-curable first adhesive layer 21 is irradiated with energy rays. The adhesive sheet 100 for workpiece processing according to this embodiment provides a second adhesive layer 22, which is not energy ray-curable, as an intermediate layer between the substrate 10 and the energy ray-curable first adhesive layer 21, thereby achieving excellent adhesion between the substrate 10 and the second adhesive layer 22. This suppresses peeling between the substrate 10 and the second adhesive layer 22. Furthermore, by configuring each adhesive layer so that the difference in polarity between the non-energy ray-curable adhesive contained in the second adhesive layer 22 and the energy ray-curable adhesive contained in the first adhesive layer 21 is small, it is believed that the affinity between the first adhesive layer 21 and the second adhesive layer 22 is improved. This improves adhesion between the second main surface 21B of the first adhesive layer 21 and the first main surface 22A of the second adhesive layer 22, and thus when the first adhesive layer 21 of the adhesive sheet for workpiece processing 100 is peeled from the workpiece after irradiation with energy rays, separation at the interface between the second main surface 21B of the first adhesive layer 21 and the first main surface 22A of the second adhesive layer 22 is suppressed. As a result, when the workpiece is peeled from the first adhesive layer 21 of the adhesive sheet for workpiece processing 100, separation of the energy ray-curable first adhesive layer 21 from the substrate 10 is suppressed. Furthermore, because of the improved adhesion between the second main surface 21B of the first adhesive layer 21 and the first main surface 22A of the second adhesive layer 22, when the workpiece is peeled from the first adhesive layer 21 of the adhesive sheet for workpiece processing 100, the occurrence of adhesive residue on the workpiece is suppressed. Therefore, it is believed that the adhesive sheet 100 for workpiece processing according to this embodiment suppresses peeling between the substrate 10 and the first adhesive layer 21, which is an adhesive layer having energy ray curing properties, and also suppresses the occurrence of adhesive residue on the workpiece.

[0028] Although an example of the adhesive sheet for workpiece processing according to the present embodiment has been described above with reference to Fig. 1, the adhesive sheet for workpiece processing according to the present embodiment is not limited to this example. The adhesive sheet for workpiece processing according to the present embodiment can take various forms as long as it has the above-described configuration.

[0029] For example, in the adhesive sheet 100 for workpiece processing, the first adhesive layer 21 and the second adhesive layer 22 are provided on one side of the substrate 10, but they may also be provided on both sides of the substrate 10. That is, the first adhesive layer 21 and the second adhesive layer 22 may be provided not only on the first main surface 10A side of the substrate 10 but also on the second main surface 10B side. When the first adhesive layer 21 and the second adhesive layer 22 are provided on both sides of the substrate 10, the first adhesive layer 21 provided on the first main surface 10A side of the substrate 10 and the first adhesive layer 21 provided on the second main surface 10B side of the substrate 10 may be the same as or different from each other. When the first adhesive layer 21 and the second adhesive layer 22 are provided on both sides of the substrate 10, the second adhesive layer 22 provided on the first main surface 10A side of the substrate 10 and the second adhesive layer 22 provided on the second main surface 10B side of the substrate 10 may be the same as or different from each other. When the first pressure-sensitive adhesive layer 21 and the second pressure-sensitive adhesive layer 22 are provided on both surfaces of the substrate 10, the second pressure-sensitive adhesive layer 22 provided on the second main surface 10B side may be provided in direct contact with the substrate 10, and the first pressure-sensitive adhesive layer 21 may be provided in direct contact with the second pressure-sensitive adhesive layer 22. In this case, the first pressure-sensitive adhesive layer 21, the second pressure-sensitive adhesive layer 22, the substrate 10, the second pressure-sensitive adhesive layer 22, and the first pressure-sensitive adhesive layer 21 are provided in this order in the stacking direction.

[0030] Furthermore, for example, in the adhesive sheet for workpiece processing 100, a release film (not shown) may be provided on the first main surface 21A of the first adhesive layer 21. When a release film is provided, the release film is laminated on the first main surface 21A, which is the adhesive surface of the first adhesive layer 21, for example, until the adhesive sheet for workpiece processing 100 is used.

[0031] Specific examples of the layers constituting the adhesive sheet for workpiece processing according to this embodiment will be described below. In the following description, reference numerals will be omitted.

[0032] <Base material> The substrate is not particularly limited as long as it has properties suitable for the process in which the pressure-sensitive adhesive sheet for workpiece processing is used. The substrate is preferably made of a resin, and more preferably a resin film.

[0033] Examples of resins constituting the substrate include polyester resins (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyolefin resins (polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, ethylene-norbornene copolymer, norbornene resin, and ethylene copolymer (ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, etc.)), polyvinyl chloride resins (polyvinyl chloride and vinyl chloride copolymer, etc.), (meth)acrylic acid ester copolymer, polyurethane, polyamide, polyimide, polystyrene, polycarbonate, fluororesin, and ionomer. The substrate may be a single-layer film of the above resin, or a laminate film in which two or more layers are laminated. When the substrate is a laminate film, the resins in each layer may be the same or different.

[0034] Among these, the resin constituting the substrate is preferably a polyester resin. Even when the resin constituting the substrate is a polyester resin, the adhesive sheet for workpiece processing according to this embodiment is more likely to suppress peeling between the substrate and the energy ray-curable adhesive layer, and more likely to suppress adhesive residue on the workpiece.

[0035] In this specification, "(meth)acrylic" means both acrylic and methacrylic, and the same applies to other similar terms.

[0036] The substrate may contain various additives, as necessary, such as a colorant, a flame retardant, a plasticizer, an antistatic agent, a lubricant, a filler, etc. Furthermore, since the first pressure-sensitive adhesive layer is energy ray-curable, it is preferable that the substrate be transparent to energy rays.

[0037] The thickness of the substrate is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 30 μm or more, and even more preferably 50 μm or more. The thickness of the substrate is preferably 500 μm or less, more preferably 300 μm or less, even more preferably 100 μm or less, and even more preferably 90 μm or less.

[0038] If the thickness of the substrate is 5 μm or more, the adhesive sheet for workpiece processing tends to have an appropriate strength suitable for processing the workpiece, making it easier to support the workpiece.If the thickness of the substrate is 500 μm or less, the adhesive sheet for workpiece processing tends to have flexibility. Furthermore, if the thickness of the substrate is 5 μm or more, for example, dicing of the workpiece becomes easier, and if the thickness of the substrate is 500 μm or less, for example, expanding becomes easier.

[0039] The substrate can be obtained by a known method, for example, by molding a resin composition containing a resin and additives added as needed by a casting method, a calendar method, a T-die extrusion method, an inflation method, or the like.

[0040] <First adhesive layer> The first pressure-sensitive adhesive layer is energy ray-curable. The first pressure-sensitive adhesive layer is not particularly limited as long as it is energy ray-curable, and is formed from a pressure-sensitive adhesive composition containing various types of pressure-sensitive adhesives. In the following description, the pressure-sensitive adhesive composition for forming the first pressure-sensitive adhesive layer may be referred to as the first pressure-sensitive adhesive composition.

[0041] Examples of adhesives having energy ray curability (energy ray curable adhesives) include acrylic, rubber, silicone, urethane, polyester, and polyvinyl ether adhesives. The energy ray curable adhesive is selected taking into consideration the application and the type of workpiece to be attached. Among these, the energy ray curable adhesive is preferably an acrylic adhesive, from the viewpoints of easily exerting adhesive strength with the workpiece and more effectively suppressing the occurrence of adhesive residue on the workpiece.

[0042] When the first adhesive layer attached to the workpiece is irradiated with energy rays, the energy ray-curable adhesive hardens and its adhesive strength to the workpiece decreases. This makes it possible to easily separate the workpiece from the adhesive sheet for workpiece processing. From the viewpoint of ease of handling the energy ray irradiation device, it is more preferable that the energy ray-curable adhesive is an ultraviolet-curable adhesive.

[0043] (energy ray curable adhesive) The energy ray-curable adhesive agent is composed of an energy ray-curable adhesive resin. The energy ray-curable adhesive resin may contain the components exemplified in (I) to (III) below. The adhesive resin preferably contains any one of the components (I), (II), or (III) below. In this specification, the energy ray-curable adhesive resin collectively refers to the components exemplified in (I) to (III) below.

[0044] (I): A component containing a non-energy ray curable polymer and an energy ray curable compound. (II): A component that does not contain an energy ray-curable compound and contains an energy ray-curable polymer in which an unsaturated group has been introduced into the side chain of a non-energy ray-curable polymer. (III): A component containing an energy ray-curable compound and an energy ray-curable polymer in which an unsaturated group has been introduced into the side chain of a non-energy ray-curable polymer.

[0045] In the adhesive resin, the non-energy ray curable polymer is preferably a (meth)acrylic copolymer. The (meth)acrylic copolymer as the non-energy ray curable polymer can be composed of the same components as the (meth)acrylic copolymer before being reacted with the unsaturated group-containing compound, which will be described later in the section on (meth)acrylic copolymers.

[0046] [Energy ray curable compound] The energy ray-curable compound has an energy ray-curable double bond in the molecule, and is a compound that polymerizes and hardens when irradiated with energy rays (for example, ultraviolet rays).

[0047] The energy ray-curable compound is preferably a (meth)acrylic compound. The energy ray-curable compound is preferably an ultraviolet ray-curable compound. The energy ray-curable compound is more preferably an ultraviolet ray-curable (meth)acrylic compound.

[0048] Examples of the energy ray curable compound include low molecular weight compounds having an energy ray polymerizable group (monofunctional monomers, polyfunctional monomers, monofunctional oligomers, and polyfunctional oligomers). Specific examples of the energy ray curable compound include acrylates such as trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butylene glycol diacrylate, and 1,6-hexanediol diacrylate; acrylates containing a cyclic aliphatic skeleton such as dicyclopentadiene dimethoxy diacrylate and isobornyl acrylate; and acrylate compounds such as polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate oligomer, epoxy-modified acrylate, polyether acrylate, and itaconic acid oligomer. One type of energy ray curable compound may be used alone, or two or more types may be used in combination.

[0049] The molecular weight of the energy ray-curable compound is usually 100 or more and 30,000 or less, and preferably about 300 or more and 10,000 or less. If the molecular weight of the energy ray-curable compound is 100 or more, the effect of suppressing adhesive residue is enhanced. If the molecular weight of the energy ray-curable compound is 300 or more, the effect of suppressing adhesive residue is further enhanced.

[0050] The energy ray-curable compound is preferably a polyfunctional energy ray-curable compound. The number of functional groups in the energy ray-curable compound is preferably 2 or more, more preferably 5 or more, and even more preferably 8 or more. When the number of functional groups is within the above range, the effect of suppressing adhesive transfer is further enhanced.

[0051] [(Meth)acrylic copolymer] It is also preferable that the energy ray-curable pressure-sensitive adhesive further contains a (meth)acrylic copolymer, which is different from the above-mentioned energy ray-curable compound.

[0052] The (meth)acrylic copolymer preferably has an energy ray-curable carbon-carbon double bond, that is, the energy ray-curable pressure-sensitive adhesive preferably contains an energy ray-curable compound and an energy ray-curable (meth)acrylic copolymer.

[0053] The energy ray-curable adhesive preferably contains 10 parts by mass or more of the energy ray-curable compound per 100 parts by mass of the (meth)acrylic copolymer, more preferably 20 parts by mass or more, and even more preferably 25 parts by mass or more. The energy ray-curable adhesive preferably contains 200 parts by mass or less of the energy ray-curable compound per 100 parts by mass of the (meth)acrylic copolymer, more preferably 160 parts by mass or less, and even more preferably 120 parts by mass or less.

[0054] The weight average molecular weight (Mw) of the (meth)acrylic copolymer is preferably 50,000 (50,000) or more, more preferably 100,000 (100,000) or more, and even more preferably 300,000 (300,000) or more. The weight average molecular weight (Mw) of the (meth)acrylic copolymer is preferably 1,500,000 (1.5 million) or less, and more preferably 1,000,000 (1 million) or less.

[0055] The weight average molecular weight (Mw) in this specification is a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene. The weight average molecular weight (Mw) in this specification can be measured, for example, under the following measurement conditions.

[0056] <Measurement conditions> Measuring device: Tosoh Corporation, HLC-8320 GPC columns (passed in the following order): Tosoh Corporation TSK gel superH-H TSK gel super HM-H TSK gel superH2000 Measurement solvent: tetrahydrofuran ·Measurement temperature: 40℃

[0057] The (meth)acrylic copolymer is preferably a (meth)acrylic acid ester polymer (hereinafter sometimes referred to as "energy ray curable polymer") having a functional group having energy ray curability (energy ray curable group) introduced into the side chain.

[0058] Energy beam curable polymers The energy ray-curable polymer is preferably a copolymer obtained by reacting a (meth)acrylic copolymer having a functional group-containing monomer unit with an unsaturated group-containing compound having a functional group that bonds to the functional group of the (meth)acrylic copolymer.

[0059] The (meth)acrylic copolymer preferably contains a structural unit derived from a functional group-containing monomer and a structural unit derived from a (meth)acrylic acid ester monomer or a derivative of a (meth)acrylic acid ester monomer.

[0060] The functional group-containing monomer as a constituent unit of the (meth)acrylic copolymer is preferably a monomer having a polymerizable double bond and a functional group in the molecule, and the functional group is preferably at least one selected from the group consisting of a hydroxy group, a carboxy group, an amino group, a substituted amino group, an epoxy group, etc.

[0061] Examples of hydroxy group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. One type of hydroxy group-containing monomer may be used alone, or two or more types may be used in combination.

[0062] Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. The carboxyl group-containing monomer may be used alone or in combination of two or more.

[0063] Examples of the amino group-containing monomer or substituted amino group-containing monomer include aminoethyl (meth)acrylate, n-butylaminoethyl (meth)acrylate, etc. The amino group-containing monomer or substituted amino group-containing monomer may be used alone or in combination of two or more.

[0064] As the (meth)acrylic acid ester monomer constituting the (meth)acrylic copolymer, in addition to alkyl (meth)acrylates in which the number of carbon atoms in the alkyl group is 1 or more and 20 or less, for example, monomers having an alicyclic structure in the molecule (alicyclic structure-containing monomers) are preferably used.

[0065] The alkyl (meth)acrylate is preferably an alkyl (meth)acrylate having an alkyl group with 1 or more and 18 or less carbon atoms. Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. One or more alkyl (meth)acrylates may be used alone or in combination. From the viewpoints of facilitating adjustment of the polarity of the energy ray-curable pressure-sensitive adhesive, further suppressing peeling between the substrate and the energy ray-curable pressure-sensitive adhesive layer, and further suppressing adhesive residue on the workpiece, it is preferable to use n-butyl (meth)acrylate, and more preferably n-butyl acrylate, as the alkyl (meth)acrylate.

[0066] Preferred examples of the alicyclic structure-containing monomer include cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, adamantyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate. The alicyclic structure-containing monomer may be used alone or in combination of two or more.

[0067] Furthermore, the (meth)acrylic copolymer preferably contains structural units derived from the functional group-containing monomer in a proportion of 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more. The (meth)acrylic copolymer preferably contains the structural units derived from the functional group-containing monomer in a proportion of 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less.

[0068] Furthermore, the (meth)acrylic copolymer preferably contains structural units derived from a (meth)acrylic acid ester monomer or a derivative thereof in a proportion of 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. The (meth)acrylic copolymer preferably contains structural units derived from a (meth)acrylic acid ester monomer or a derivative thereof in a proportion of 99% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less.

[0069] The (meth)acrylic copolymer can be obtained by copolymerizing the above-mentioned functional group-containing monomer with a (meth)acrylic acid ester monomer or a derivative thereof in a conventional manner. In addition to the above-mentioned monomers, the (meth)acrylic copolymer may contain at least one structural unit selected from the group consisting of dimethylacrylamide, vinyl formate, vinyl acetate, styrene, and the like.

[0070] An energy ray-curable polymer can be obtained by reacting the (meth)acrylic copolymer having the functional group-containing monomer unit with an unsaturated group-containing compound having a functional group bonded to the functional group.

[0071] The functional group of the unsaturated group-containing compound can be appropriately selected depending on the type of functional group of the functional group-containing monomer unit of the (meth)acrylic copolymer.For example, when the functional group of the (meth)acrylic copolymer is a hydroxy group, an amino group, or a substituted amino group, the functional group of the unsaturated group-containing compound is preferably an isocyanate group or an epoxy group, and when the functional group of the (meth)acrylic copolymer is an epoxy group, the functional group of the unsaturated group-containing compound is preferably an amino group, a carboxy group, or an aziridinyl group.

[0072] The unsaturated group-containing compound contains at least one energy ray-polymerizable carbon-carbon double bond in one molecule, preferably 1 to 6, and more preferably 1 to 4.

[0073] Examples of unsaturated group-containing compounds include 2-methacryloyloxyethyl isocyanate (2-isocyanatoethyl methacrylate), meta-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1-(bisacryloyloxymethyl)ethyl isocyanate; acryloyl monoisocyanate compounds obtained by reacting a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth)acrylate; acryloyl monoisocyanate compounds obtained by reacting a diisocyanate compound or a polyisocyanate compound with a polyol compound and hydroxyethyl (meth)acrylate; glycidyl (meth)acrylate; (meth)acrylic acid, 2-(1-aziridinyl)ethyl (meth)acrylate, 2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline, and the like.

[0074] The unsaturated group-containing compound is preferably used in a proportion (addition rate) of 50 mol % or more, more preferably 60 mol % or more, and even more preferably 70 mol % or more, relative to the number of moles of the functional group-containing monomer in the (meth)acrylic copolymer. The unsaturated group-containing compound is preferably used in a proportion (addition rate) of 95 mol % or less, more preferably 93 mol % or less, and even more preferably 90 mol % or less, relative to the number of moles of the functional group-containing monomer in the (meth)acrylic copolymer.

[0075] In the reaction between the (meth)acrylic copolymer and the unsaturated group-containing compound, the reaction temperature, pressure, solvent, time, presence or absence of a catalyst, and type of catalyst can be appropriately selected depending on the combination of the functional groups of the (meth)acrylic copolymer and the unsaturated group-containing compound. As a result, the functional groups of the (meth)acrylic copolymer and the unsaturated group-containing compound react with each other, and an unsaturated group is introduced into the side chain of the (meth)acrylic copolymer (i.e., a functional group having energy ray curability (energy ray-curable group) is introduced into the side chain), thereby obtaining an energy ray-curable polymer.

[0076] When a catalyst is used in the reaction between the (meth)acrylic copolymer and the unsaturated group-containing compound, the reaction between the (meth)acrylic copolymer and the unsaturated group-containing compound is preferably carried out in the presence of at least one organometallic catalyst selected from the group consisting of organotin compounds, zirconium complexes, zinc complexes, and zirconium-containing metal soaps. The use of an organometallic catalyst facilitates improved adhesion to the second pressure-sensitive adhesive layer, and more effectively prevents peeling between the substrate and the energy ray-curable pressure-sensitive adhesive layer. From the perspective of environmental friendliness, the organometallic catalyst is preferably at least one organometallic catalyst selected from the group consisting of zirconium complexes, zinc complexes, and zirconium-containing metal soaps.

[0077] The organometallic catalyst may be an organotin compound. Organotin compounds as organometallic catalysts have a high advantage in terms of reactivity between the (meth)acrylic copolymer and the unsaturated group-containing compound. Specific examples of organotin compounds include dibutyltin dilaurate (DBTDL), dioctyltin dilaurate (DOTDL), dibutyltin diacetate (DBTDA), dioctyltin diacetate (DOTDA), dioctyltin maleate (DOTM), and dibutyltin maleate (DBTM). Among these, the organotin compound as the organometallic catalyst used in the reaction between the (meth)acrylic copolymer and the unsaturated group-containing compound preferably contains dibutyltin dilaurate (DBTDL).

[0078] When an organotin compound is used as the organometallic catalyst, the content of the organotin compound in the adhesive resin is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and even more preferably 0.02 parts by mass or more, relative to 100 parts by mass of the total amount of the monomers constituting the (meth)acrylic copolymer. The content of the organotin compound in the adhesive resin is preferably less than 0.3 parts by mass, more preferably 0.1 parts by mass or less, and even more preferably 0.07 parts by mass or less, relative to 100 parts by mass of the total amount of the monomers constituting the (meth)acrylic copolymer.

[0079] From the viewpoints of making it easier to adjust the polarity of the energy ray-curable adhesive, making it easier to suppress peeling between the substrate and the energy ray-curable adhesive layer, and making it easier to suppress adhesive residue on the workpiece, it is preferable to use a (meth)acrylic copolymer that contains the most structural units derived from n-butyl(meth)acrylate, and it is more preferable to use a (meth)acrylic copolymer that contains the most structural units derived from n-butyl acrylate. From the viewpoints of making it easier to adjust the polarity of the energy ray-curable adhesive, making it easier to suppress peeling between the substrate and the energy ray-curable adhesive layer, and making it easier to suppress adhesive residue on the workpiece, it is preferable that the (meth)acrylic copolymer contains structural units derived from n-butyl(meth)acrylate in a proportion of 50% by mass or more and 99% by mass or less. That is, in the energy ray-curable adhesive, the acrylic adhesive is a (meth)acrylic acid ester copolymer having a functional group (energy ray-curable group) having energy ray curability introduced into the side chain, and it is preferable that the acrylic adhesive contains a (meth)acrylic acid ester copolymer containing the most structural units derived from n-butyl (meth)acrylate, and it is more preferable that the acrylic adhesive contains a (meth)acrylic acid ester copolymer containing the most structural units derived from n-butyl acrylate.

[0080] The weight average molecular weight (Mw) of the energy ray curable polymer is preferably 50,000 (50,000) or more, more preferably 100,000 (100,000) or more, and even more preferably 300,000 (300,000) or more. The weight average molecular weight (Mw) of the energy ray curable polymer is preferably 1,500,000 (1.5 million) or less, and more preferably 1,000,000 (1 million) or less.

[0081] [Photopolymerization initiator] When the first pressure-sensitive adhesive composition contains a photocurable compound, specifically an ultraviolet-curable compound (e.g., an ultraviolet-curable resin), it is preferable that the first pressure-sensitive adhesive composition contains a photopolymerization initiator. When the first pressure-sensitive adhesive composition contains a photopolymerization initiator, the polymerization and curing time and the amount of light irradiation can be reduced.

[0082] Specific examples of the photopolymerization initiator include a benzoin compound, an acetophenone compound, an acylphosphine oxide compound, a titanocene compound, a thioxanthone compound, and a peroxide compound. Further examples of the photopolymerization initiator include a photosensitizer such as an amine or a quinone.

[0083] More specific examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzo Examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyrolnitrile, dibenzyl, diacetyl, 8-chloroanthraquinone, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide. The photopolymerization initiator may be used alone or in combination of two or more.

[0084] The photopolymerization initiator is preferably used in an amount of 0.01 parts by mass or more, more preferably 0.03 parts by mass or more, and even more preferably 0.05 parts by mass or more, per 100 parts by mass of the adhesive resin of any one of the above embodiments (I), (II), or (III). The photopolymerization initiator is preferably used in an amount of 10 parts by mass or less, more preferably 5 parts by mass or less, per 100 parts by mass of the adhesive resin of any one of the above (I), (II), or (III).

[0085] When the adhesive resin contains a (meth)acrylic copolymer and an energy ray-curable compound, the photopolymerization initiator is preferably used in an amount of 0.1 parts by mass or more, and more preferably 0.5 parts by mass or more, per 100 parts by mass of the energy ray-curable compound. When the adhesive resin contains a (meth)acrylic copolymer and an energy ray-curable compound, the photopolymerization initiator is preferably used in an amount of 10 parts by mass or less, and more preferably 6 parts by mass or less, per 100 parts by mass of the energy ray-curable compound.

[0086] [Crosslinking agent] The first pressure-sensitive adhesive composition may contain a crosslinking agent. The crosslinking agent may be a polyfunctional compound reactive with functional groups contained in the (meth)acrylic copolymer or the like. Examples of polyfunctional compounds used in the first pressure-sensitive adhesive composition include isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, oxazoline compounds, metal alkoxide compounds, metal chelate compounds, metal salts, ammonium salts, and reactive phenolic resins.

[0087] When the adhesive resin is the adhesive resin of the above embodiment (I), the amount of the crosslinking agent is preferably 0.01 parts by mass or more, and more preferably 1 part by mass or more, per 100 parts by mass of the (meth)acrylic copolymer. When the adhesive resin is the adhesive resin of the above embodiment (I), the amount of the crosslinking agent is preferably 30 parts by mass or less, and more preferably 20 parts by mass or less, per 100 parts by mass of the (meth)acrylic copolymer.

[0088] When the adhesive resin is an adhesive resin of the above embodiment (II), the amount of crosslinking agent is preferably 0.01 parts by mass or more, and more preferably 0.1 parts by mass or more, per 100 parts by mass of the polymer having an unsaturated group introduced into the side chain of the non-energy ray-curable polymer. When the adhesive resin is an adhesive resin of the above embodiment (II), the amount of crosslinking agent is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less, per 100 parts by mass of the polymer having an unsaturated group introduced into the side chain of the non-energy ray-curable polymer.

[0089] When the adhesive resin is an adhesive resin of the above-mentioned embodiment (III), the amount of the crosslinking agent is preferably 0.01 parts by mass or more, and more preferably 0.1 parts by mass or more, per 100 parts by mass of the polymer having an unsaturated group introduced into the side chain of the non-energy ray-curable polymer. When the adhesive resin is an adhesive resin of the above embodiment (III), the amount of crosslinking agent is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less, per 100 parts by mass of the polymer having an unsaturated group introduced into the side chain of the non-energy ray-curable polymer.

[0090] In addition to the above components, the first pressure-sensitive adhesive composition may contain other components such as an antistatic agent, an antioxidant, a softener (plasticizer), a filler, an anti-rust agent, a pigment, and a dye.

[0091] The thickness of the first adhesive layer is, for example, preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more. If the thickness of the first adhesive layer is 1 μm or more, the adhesive sheet for workpiece processing is more likely to exhibit good adhesive strength to the workpiece. The thickness of the first adhesive layer is, for example, preferably 70 μm or less, more preferably 50 μm or less, even more preferably 30 μm or less, and even more preferably 10 μm or less. If the thickness of the first adhesive layer is 70 μm or less, the workpiece is more likely to be peeled from the adhesive layer of the adhesive sheet for workpiece processing.

[0092] <Second adhesive layer> The second pressure-sensitive adhesive layer is a non-energy ray-curable pressure-sensitive adhesive layer that does not have energy ray curability. The second pressure-sensitive adhesive layer is not particularly limited as long as it is non-energy ray-curable. The second pressure-sensitive adhesive layer contains a non-energy ray-curable pressure-sensitive adhesive that does not have energy ray curability. If the second pressure-sensitive adhesive layer is non-energy ray-curable, it is formed from a pressure-sensitive adhesive composition containing various types of pressure-sensitive adhesives. In the following description, the pressure-sensitive adhesive composition for forming the second pressure-sensitive adhesive layer may be referred to as the second pressure-sensitive adhesive composition.

[0093] Examples of non-energy ray curable adhesives include acrylic, rubber, silicone, urethane, polyester, and polyvinyl ether adhesives. The non-energy ray curable adhesive is preferably selected in consideration of the type of adhesive used in the first adhesive layer. Among these, the non-energy ray curable adhesive is preferably an acrylic adhesive, from the viewpoint of easily exhibiting excellent adhesive strength and adhesion between the substrate and the first adhesive layer. The non-energy ray curable acrylic adhesive preferably contains a non-energy ray curable (meth)acrylic copolymer.

[0094] [(Meth)acrylic copolymer] The non-energy ray-curable (meth)acrylic copolymer preferably contains a structural unit derived from a functional group-containing monomer and a structural unit derived from a (meth)acrylic acid ester monomer or a derivative of a (meth)acrylic acid ester monomer.

[0095] As the (meth)acrylic acid ester monomer, from the viewpoint of easily exhibiting excellent adhesive strength, a (meth)acrylic acid alkyl ester having an alkyl group with 1 to 20 carbon atoms is preferable, and a (meth)acrylic acid alkyl ester having an alkyl group with 1 to 14 carbon atoms is more preferable.

[0096] Examples of acrylic acid alkyl ester monomers include methyl acrylate, ethyl acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, and stearyl (meth)acrylate. The acrylic acid alkyl ester monomers may be used alone or in combination of two or more. Among these, from the viewpoints of easily adjusting the polarity of the non-energy ray-curable pressure-sensitive adhesive and more easily suppressing peeling between the substrate and the energy ray-curable pressure-sensitive adhesive layer, it is preferable to use n-butyl (meth)acrylate, and more preferably n-butyl acrylate, as the acrylic acid alkyl ester monomer.

[0097] The functional group-containing monomer preferably contains at least one functional group selected from the group consisting of a hydroxy group, a carboxy group, an amino group, etc. Among these, the functional group-containing monomer is preferably a carboxy group-containing monomer from the viewpoints of facilitating adjustment of the reactivity with a crosslinking agent when used in combination with the crosslinking agent, and the polarity of the non-energy ray-curable pressure-sensitive adhesive, as well as making it easier to suppress peeling between the substrate and the energy ray-curable pressure-sensitive adhesive layer.

[0098] Examples of carboxy group-containing monomers include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. The carboxy group-containing monomers may be used alone or in combination of two or more. Among these, the carboxy group-containing monomer is preferably acrylic acid, from the viewpoints of improving the reactivity with a crosslinking agent when used in combination with the crosslinking agent, facilitating adjustment of the polarity of the non-energy ray-curable pressure-sensitive adhesive, and further suppressing peeling between the substrate and the energy ray-curable pressure-sensitive adhesive layer.

[0099] The non-energy ray-curable (meth)acrylic copolymer may further contain, as necessary, structural units derived from other monomers than the (meth)acrylic acid ester monomer or derivatives of the (meth)acrylic acid ester monomer. In this case, the (meth)acrylic acid ester monomer or derivatives of the (meth)acrylic acid ester monomer are referred to as the main monomer component, and the other monomers are referred to as the comonomer component. The main monomer component has a low glass transition temperature (low Tg) and is a component that imparts adhesiveness, while the comonomer component has a high glass transition temperature (high Tg) and is a component that improves cohesive strength, etc. The non-energy ray-curable (meth)acrylic copolymer contains the largest amount of structural units derived from the main monomer component.

[0100] Examples of the comonomer component include methyl methacrylate, isobornyl (meth)acrylate, acryloylmorpholine, adamantyl (meth)acrylate, dimethylacrylamide, acrylamide, etc. The comonomer component may be used alone or in combination of two or more.

[0101] From the viewpoint of imparting tackiness, the non-energy ray-curable (meth)acrylic copolymer preferably contains 40% by mass or more and 99% by mass or less of structural units derived from (meth)acrylic acid alkyl esters or structural units derived from derivatives of (meth)acrylic acid ester monomers. The non-energy ray-curable (meth)acrylic copolymer more preferably contains 45% by mass or more of structural units derived from (meth)acrylic acid alkyl esters or structural units derived from derivatives of (meth)acrylic acid ester monomers, even more preferably contains 55% by mass or more, and even more preferably contains 60% by mass or more. The non-energy ray-curable (meth)acrylic copolymer more preferably contains 98% by mass or less of structural units derived from (meth)acrylic acid alkyl esters or structural units derived from derivatives of (meth)acrylic acid ester monomers, even more preferably contains 97% by mass or less, and even more preferably contains 95% by mass or less of structural units derived from (meth)acrylic acid alkyl esters. When the non-energy ray-curable (meth)acrylic copolymer does not contain a comonomer component, it preferably contains structural units derived from a (meth)acrylic acid alkyl ester or structural units derived from a derivative of a (meth)acrylic acid ester monomer in a proportion of 70% by mass or more and 99% by mass or less, and more preferably 80% by mass or more and 99% by mass or less.

[0102] The non-energy ray-curable (meth)acrylic copolymer preferably contains structural units derived from reactive functional group-containing monomers in the range of 1% by mass or more and 30% by mass or less, from the viewpoint of reactivity with a crosslinking agent when used in combination with the crosslinking agent. The non-energy ray-curable (meth)acrylic copolymer more preferably contains structural units derived from reactive functional group-containing monomers in the range of 3% by mass or more, and even more preferably contains structural units derived from reactive functional group-containing monomers in the range of 5% by mass or more. The non-energy ray-curable (meth)acrylic copolymer more preferably contains structural units derived from reactive functional group-containing monomers in the range of 25% by mass or less, and even more preferably contains structural units derived from reactive functional group-containing monomers in the range of 20% by mass or less.

[0103] In order to improve cohesive strength and the like, the content of structural units derived from other monomers as comonomer components in the non-energy ray-curable (meth)acrylic copolymer may be in the range of 0% by mass or more and 30% by mass or less. When structural units derived from other monomers as comonomer components are contained, the non-energy ray-curable (meth)acrylic copolymer preferably contains structural units derived from other monomers as comonomer components in the range of 1% by mass or more, more preferably 2% by mass or more. The non-energy ray-curable (meth)acrylic copolymer preferably contains structural units derived from other monomers as comonomer components in the range of 25% by mass or less, more preferably 20% by mass or less. The total amount of structural units in the non-energy ray-curable (meth)acrylic copolymer is 100% by mass.

[0104] The weight average molecular weight (Mw) of the non-energy ray curable (meth)acrylic copolymer is preferably 50,000 (50,000) or more, more preferably 100,000 (100,000) or more, and even more preferably 300,000 (300,000) or more. The weight average molecular weight (Mw) of the non-energy ray curable polymer is preferably 1,500,000 (1.5 million) or less, and more preferably 1,000,000 (1 million) or less.

[0105] In order to facilitate adjustment of the polarity of the non-energy ray-curable adhesive, to more easily prevent peeling between the substrate and the energy ray-curable adhesive layer, and to more easily prevent adhesive residue on the workpiece, it is preferable to use a (meth)acrylic copolymer containing the most structural units derived from n-butyl (meth)acrylate as the non-energy ray-curable (meth)acrylic copolymer, and more preferably to use a (meth)acrylic copolymer containing the most structural units derived from n-butyl acrylate. That is, in the non-energy ray-curable adhesive, it is preferable that the acrylic adhesive contains a (meth)acrylic copolymer containing the most structural units derived from n-butyl (meth)acrylate, and more preferably to contain a (meth)acrylic copolymer containing the most structural units derived from n-butyl acrylate. In this regard, it is preferable that the (meth)acrylic copolymer contains, for example, structural units derived from n-butyl (meth)acrylate in a proportion of 40% by mass or more and 99% by mass or less.

[0106] Furthermore, from the viewpoint of making it easier to adjust the polarity of the non-energy ray-curable adhesive, more easily suppressing peeling between the substrate and the energy ray-curable adhesive layer, and more easily suppressing adhesive residue on the workpiece, it is preferable that the non-energy ray-curable (meth)acrylic copolymer further contains a structural unit derived from acrylic acid. That is, it is also preferable that the (meth)acrylic copolymer further contains a structural unit derived from acrylic acid. In this regard, it is also preferable that the (meth)acrylic copolymer contains, for example, a structural unit derived from acrylic acid in a proportion of 1% by mass or more and 30% by mass or less.

[0107] [Crosslinking agent] From the viewpoint of improving adhesion to the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive composition preferably contains a crosslinking agent. As the crosslinking agent, a polyfunctional compound having reactivity with functional groups of the non-energy ray-curable (meth)acrylic copolymer or the like can be used. Examples of the polyfunctional compound in the second pressure-sensitive adhesive composition include the same compounds as the polyfunctional compounds described above in relation to the crosslinking agent for the first pressure-sensitive adhesive layer.

[0108] The amount of crosslinking agent blended is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, per 100 parts by mass of the non-energy ray-curable (meth)acrylic copolymer. The amount of crosslinking agent blended is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, per 100 parts by mass of the non-energy ray-curable (meth)acrylic copolymer. If the second pressure-sensitive adhesive composition contains 0.01 parts by mass or more of the crosslinking agent per 100 parts by mass of the non-energy ray-curable (meth)acrylic copolymer, adhesion to the first pressure-sensitive adhesive layer is more likely to be improved.

[0109] In addition to the above components, the second pressure-sensitive adhesive composition may contain other components such as an antistatic agent, an antioxidant, a softener (plasticizer), a filler, an anti-rust agent, a pigment, and a dye.

[0110] The thickness of the second pressure-sensitive adhesive layer is, for example, preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more. The thickness of the second pressure-sensitive adhesive layer is, for example, preferably 70 μm or less, more preferably 50 μm or less, even more preferably 30 μm or less, and even more preferably 10 μm or less. If the thickness of the second pressure-sensitive adhesive layer is in the range of 1 μm or more and 70 μm or less, it is easy to exhibit good adhesive strength, and the adhesion between the substrate and the first pressure-sensitive adhesive layer is easy to improve.

[0111] <Polarity of each adhesive> In the adhesive sheet for workpiece processing according to this embodiment, the absolute value of the difference between the polarity value of the non-energy ray curable adhesive contained in the second adhesive layer and the polarity value of the energy ray curable adhesive contained in the first adhesive layer is 1.00 (cal / cm 3 ) 0.5 From the viewpoint of more easily preventing peeling between the substrate and the energy ray-curable adhesive layer and more easily preventing adhesive residue on the workpiece, the absolute value of the difference between the polarity value of the non-energy ray-curable adhesive and the polarity value of the energy ray-curable adhesive is 0.98 (cal / cm 3 ) 0.5 It is preferable that the calorie content is 0.96 (cal / cm 3 ) 0.5 More preferably, it is 0.95 (cal / cm 3 ) 0.5 The lower limit of the absolute value of the difference between the polarity value of the non-energy ray-curable adhesive and the polarity value of the energy ray-curable adhesive is not particularly limited, and may be, for example, 0.00 (cal / cm 3 ) 0.5 may be greater than 0.01 (cal / cm 3 ) 0.5 It may be 0.10 (cal / cm 3 ) 0.5 It may be 0.20 (cal / cm 3 ) 0.5 It may be more than that.

[0112] From the viewpoint of more easily preventing peeling between the substrate and the energy ray-curable adhesive layer and more easily preventing adhesive residue on the workpiece, the polarity value of the non-energy ray-curable adhesive contained in the second adhesive layer is 9.80 (cal / cm 3 ) 0.5 The polarity value of the non-energy ray curable adhesive is preferably 9.85 (cal / cm 3 ) 0.5 More preferably, it is 9.90 (cal / cm 3 ) 0.5 More preferably, it is 9.95 (cal / cm 3 )0.5 It is even more preferable that this is the case.

[0113] The absolute value of the difference between the polarity value of the non-energy ray curable adhesive and the polarity value of the energy ray curable adhesive is 1.00 (cal / cm 3 ) 0.5 The method for adjusting the polarity is not particularly limited. The polarity of the non-energy ray-curable adhesive and the polarity of the energy ray-curable adhesive can be adjusted by the monomer components used to polymerize the polymer constituting the adhesive. When the energy ray-curable adhesive is composed of, for example, the adhesive resin of the above-mentioned embodiment (II), it is preferable that the monomer component most abundant among the monomer components used to polymerize the energy ray-curable polymer having an unsaturated group introduced into the side chain of the non-energy ray-curable polymer is a monomer component having a polarity similar to that of the monomer component most abundant among the monomer components used to polymerize the polymer constituting the non-energy ray-curable adhesive, and more preferably a monomer component having the same polarity as that of the monomer component most abundant. In this way, for example, the absolute value of the difference in polarity between the polymers constituting the non-energy ray-curable adhesive and the energy ray-curable adhesive can be adjusted by selecting monomers with similar polarity values ​​as the monomer components used to synthesize the polymers constituting each of the adhesives.

[0114] The polarity value of the energy ray-curable adhesive contained in the first adhesive layer is not particularly limited, and may be, for example, 10.00 (cal / cm 3 ) 0.5 The polarity value of the energy ray curable adhesive may be 10.10 (cal / cm 3 ) 0.5 It may be 10.30 (cal / cm 3 ) 0.5 It may be 10.50 (cal / cm 3 ) 0.5From the viewpoint of more easily suppressing peeling between the substrate and the energy ray-curable pressure-sensitive adhesive layer and more easily suppressing adhesive residue on the workpiece, it is preferable that the polarity value of the energy ray-curable pressure-sensitive adhesive contained in the first pressure-sensitive adhesive layer is larger than the polarity value of the non-energy ray-curable pressure-sensitive adhesive contained in the second pressure-sensitive adhesive layer.

[0115] The unit of polarity value (cal / cm 3 ) 0.5 is 1 (cal / cm 3 ) 0.5 ≒2.05(J / cm 3 ) 0.5 , and the polarity value unit (cal / cm 3 ) 0.5 is 1 (cal / cm 3 ) 0.5 ≒2.05 (MPa) 0.5 It can also be converted into

[0116] In the adhesive sheet for workpiece processing according to this embodiment, the polarity value of each adhesive can be calculated, for example, by the Fedors method. That is, the polarity value of each adhesive is calculated by the square root of the sum of the molar calorific values ​​divided by the sum of the molar volumes. Specifically, the polarity value of each adhesive can be calculated by the following formula (F1). For example, if n monomers are used to synthesize each adhesive, the polarity value of each adhesive layer can be calculated by calculating the sum of the molar calorific values ​​from the first monomer to the nth monomer, calculating the sum of the molar volumes from the first monomer to the nth monomer, dividing the sum of the molar calorific values ​​by the sum of the molar volumes, and then raising to the power of 0.5.

[0117]

number

[0118] In the formula (F1), δ is the polarity value of the adhesive, A1 is the blending ratio (mass%) of the first monomer, M1 is the molar mass (g / mol) of the first monomer, Ei1 is the molar calorific value (cal / mol) of the first monomer, and Vi1 is the molar volume (cm 3 / mol), A n is the blending ratio (mass%) of the nth monomer, M n is the molar mass of the nth monomer (g / mol), Ei n is the molar calorific value of the nth monomer (cal / mol), Vi n is the molar volume of the nth monomer (cm 3 / mol). For example, when 80 mass % of n-butyl acrylate and 20 mass % of 2-hydroxyethyl acrylate are used as monomers for the polymer constituting the adhesive, the polarity value of the adhesive can be calculated based on the formula (F1) with n-butyl acrylate as the first monomer and 2-hydroxyethyl acrylate as the second monomer. The molar calorific value and molar volume of the monomer can be calculated from the values ​​described in "Solubility Parameter Values" by Eric A. Grulke. The values ​​substituted for M, Ei, and Vi in the formula (F1) can be, for example, the values ​​exemplified in the examples described below.

[0119] <Release film> In the adhesive sheet for workpiece processing according to this embodiment, a release film may be laminated on the first main surface (adhesive surface) of the first adhesive layer to protect the adhesive surface until it is attached to the workpiece. The release film is a component that is provided as needed. For example, the release film may be a release film in which a resin film is used as a base material and at least one surface of the resin film as the base material is subjected to a release treatment. Examples of resin films include films of polyester (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.) and polyolefin (polypropylene, polyethylene, etc.). The release treatment may be performed using a release agent, and examples of the release agent include silicone-based, fluorine-based, and long-chain alkyl-based agents. The thickness of the release film is not particularly limited and may be, for example, in the range of 20 μm or more and 250 μm or less.

[0120] [Manufacturing method of adhesive sheets for workpiece processing] A preferred example of a manufacturing method for the adhesive sheet for workpiece processing according to this embodiment will be described. The manufacturing method for the adhesive sheet for workpiece processing is not particularly limited. The manufacturing method for the adhesive sheet for workpiece processing preferably includes the following steps: (1) preparing a substrate, a first adhesive composition for forming a first adhesive layer having energy ray curability, a second adhesive composition for forming a second adhesive layer not having energy ray curability, and a release film; (2) applying the first adhesive composition to the release surface (release-treated surface) of the release film to form a first adhesive layer formed from the first adhesive composition; (3) applying the second adhesive composition to at least one surface of the substrate to form a second adhesive layer formed from the second adhesive composition; and (4) laminating the first adhesive layer provided on the release-treated surface of the release film and the second adhesive layer provided on the substrate so that the second adhesive layer is disposed between the substrate and the first adhesive layer.

[0121] The substrate, the first pressure-sensitive adhesive composition for forming the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive composition for forming the second pressure-sensitive adhesive layer that is not energy ray-curable, and the release film may be the same as those already described. Examples of methods for applying the first pressure-sensitive adhesive composition and the second pressure-sensitive adhesive composition include preparing a coating liquid containing each pressure-sensitive adhesive composition and, if necessary, a solvent or dispersion medium, and applying the coating liquid. The coating method is not particularly limited, and examples include spin coating, spray coating, bar coating, knife coating, roll coating, roll knife coating, blade coating, die coating, and gravure coating.

[0122] Examples of the solvent or dispersion medium include aromatic hydrocarbon solvents (benzene, toluene, etc.), ester solvents (ethyl acetate, butyl acetate, etc.), ketone solvents (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), aliphatic hydrocarbon solvents (n-pentane, n-hexane, n-heptane, etc.), and alicyclic hydrocarbon solvents (cyclopentane, cyclohexane, etc.). These solvents or dispersion mediums may be used alone or in combination of two or more.

[0123] Each pressure-sensitive adhesive layer can be formed by applying a coating liquid containing the first pressure-sensitive adhesive composition or the second pressure-sensitive adhesive composition to form a coating film, and then heating and drying the coating film.

[0124] The method for manufacturing an adhesive sheet for workpiece processing according to this embodiment is not limited to the above, and may also be a manufacturing method comprising the steps of preparing a substrate, a first adhesive composition, a second adhesive composition, and a release film, providing a second adhesive layer formed from the second adhesive composition on the substrate, and providing a first adhesive layer formed from the first adhesive composition on the surface of the second adhesive layer opposite the substrate side.

[0125] When each PSA composition contains a crosslinking agent, it is preferable to form a crosslinked structure in each PSA layer, for example, by changing the drying conditions (temperature, time, etc.) of the coating film coated with a coating liquid containing each PSA composition, or by performing a heat treatment other than drying. The PSA sheet for workpiece processing obtained by the above steps may also be seasoned. Seasoning conditions include, for example, leaving the sheet at a temperature of 20°C or higher and 50°C or lower (e.g., 23°C) and a relative humidity of 20% RH or higher and 50% RH or lower (e.g., 50% RH) for a period of 3 days to 14 days (e.g., 7 days).

[0126] [How to use adhesive sheets for workpiece processing] The shape of the adhesive sheet for workpiece processing according to this embodiment is not particularly limited as long as it comprises a substrate, a first adhesive layer, and a second adhesive layer provided between the substrate and the first adhesive layer. The adhesive sheet for workpiece processing can take any shape, such as a tape or a label.

[0127] The adhesive sheet for workpiece processing according to this embodiment can be used as an adhesive sheet for processing a workpiece. After attaching a workpiece to the first adhesive layer of the adhesive sheet for workpiece processing, various processes are performed on the workpiece while it is attached to the first adhesive layer of the adhesive sheet for workpiece processing. Examples of workpieces that can be attached to the first adhesive layer include semiconductor components such as semiconductor wafers and semiconductor packages, and transparent components such as glass substrates and glass plates. Semiconductor wafers may be, for example, silicon wafers or compound semiconductor wafers such as gallium arsenide. The term "transparent component" is not limited to glass and includes any transparent component that transmits light, including components that exhibit a visible light transmittance of 50% or more. The transparent component is preferably glass (glass substrates, glass plates, etc.).

[0128] Specifically, the adhesive sheet for workpiece processing according to this embodiment is applied, for example, as at least one selected from the group consisting of a backgrinding sheet, a dicing sheet, an expanding sheet, and a pickup sheet. The polarity of a semiconductor package, which is an encapsulated body that encloses a semiconductor element, is often relatively lower than the polarity of a semiconductor wafer. Even when the polarity of the first adhesive layer is adjusted to be closer to that of the semiconductor package, taking into account the adhesion between the first adhesive layer and the semiconductor package, the adhesive sheet for workpiece processing according to this embodiment includes an intermediate layer on the substrate, whose polarity is similar to that of the first adhesive layer. Therefore, when the first adhesive layer is irradiated with energy rays and the adhesive sheet for workpiece processing according to this embodiment is peeled from the workpiece, separation of the first adhesive layer from the substrate is suppressed. This suppresses separation of the first adhesive layer from the substrate, even when the first adhesive layer of the adhesive sheet for workpiece processing according to this embodiment is applied to a semiconductor package with a relatively low polarity. Therefore, the adhesive sheet for workpiece processing according to this embodiment is also preferably an adhesive sheet for semiconductor package processing used in semiconductor package processing. Furthermore, even when the adhesive sheet for workpiece processing according to this embodiment has cuts in the thickness direction, when the first adhesive layer is irradiated with energy rays and then the adhesive sheet for workpiece processing is peeled off from the workpiece, the first adhesive layer having energy ray curing properties is prevented from separating from the substrate, and adhesive residue on the workpiece is also prevented. Therefore, the adhesive sheet for workpiece processing according to this embodiment is also preferably a dicing sheet. Furthermore, the adhesive sheet for workpiece processing according to this embodiment is also preferably used as a dicing sheet for semiconductor packages.

[0129] When the adhesive sheet for workpiece processing is used as, for example, a dicing sheet, specifically, a dicing process is performed with a workpiece (e.g., a semiconductor wafer or semiconductor package) attached to the adhesive layer of the adhesive sheet for workpiece processing. After the dicing process, the first adhesive layer of the adhesive sheet for workpiece processing attached to the processed workpiece is irradiated with energy rays (e.g., ultraviolet light) to harden the adhesive layer. The processed workpiece is then picked up from the hardened first adhesive layer. Use of the adhesive sheet for workpiece processing according to this embodiment reduces the occurrence of adhesive residue on the surface of the picked-up processed workpiece to which the first adhesive layer was attached. Furthermore, because the first adhesive layer of the adhesive sheet for workpiece processing according to this embodiment is prevented from separating from the adhesive sheet for workpiece processing, use of the adhesive sheet for workpiece processing according to this embodiment also reduces the first adhesive layer from remaining attached to the surface of the picked-up processed workpiece to which the first adhesive layer was attached.

[0130] [Modification of the embodiment] The present invention is not limited to the above-described embodiment, and includes modifications of the above-described embodiment within the scope of achieving the object of the present invention. [Example]

[0131] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0132] Measurements and evaluations in the following examples and comparative examples were carried out by the methods shown below.

[0133] [Keying Evaluation] The surface of the substrate of the adhesive sheet for workpiece processing prepared in each Example and Comparative Example on which the first adhesive layer and the second adhesive layer were not provided (i.e., the outer surface of the substrate) was irradiated with ultraviolet light (UV) (illuminance: 230 mW / cm) using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2010m / 12"). 2 , Light intensity: 190mJ / cm2 ) to cure the first pressure-sensitive adhesive layer. The release film was then peeled from the first pressure-sensitive adhesive layer, and the sheet was cut in an environment of 23°C and 50% relative humidity to obtain a square keying test sheet with sides measuring 80 mm. Eleven lines (100 squares) were cut vertically and horizontally at 5 mm intervals in a checkerboard pattern at the center of each main surface of the keying test sheet on the pressure-sensitive adhesive layer side. Each line cut completely cut through each pressure-sensitive adhesive layer, but the cut depth into the substrate was shallow, so the substrate was not cut. Five rows of cellophane adhesive tape (Nichiban Co., Ltd., Cellotape (registered trademark) No. 405) were attached to the main surface of the keying test sheet on the first pressure-sensitive adhesive layer side with these cuts, with some of the tape overlapping. The cellophane adhesive tape attached to the main surface on the first pressure-sensitive adhesive layer side completely covered the checkerboard cuts. The sheet was left in this state for 20 minutes in an environment of 23°C and 50% relative humidity. Then, while holding the keying test sheet with one hand, the tester held one end of the cellophane adhesive tape with the other hand and quickly peeled the cellophane adhesive tape in the direction normal to the main surface of the keying test sheet. After peeling the cellophane adhesive tape, the grid-like cuts in the keying test sheet were visually observed, and the number of squares where the adhesive layer had not peeled off even partially was counted as the number of adhered squares, and the non-peeling rate (unit: %) was calculated using the following formula (F2). From the calculated non-peeling rate, the keying was evaluated according to the following evaluation criteria. A rating of A (good) was considered a pass. Non-peeling rate = (number of adhered squares / 100) × 100 (F2)

[0134] <Evaluation criteria> A (〇): Non-peeling rate is 100%. F(×): Non-peeling rate is less than 100%.

[0135] [Adhesive residue evaluation] The release film was peeled off from the first adhesive layer of the adhesive sheet for workpiece processing prepared in each Example and Comparative Example to expose the main surface (adhesive surface) of the first adhesive layer. In an environment of 23°C and 50% RH, the adhesive surface of the first adhesive layer was attached to the mirror surface of a silicon wafer as an adherend using a 2 kg rubber roller. After 20 minutes, the adhesive sheet for workpiece processing was irradiated with ultraviolet light (UV) (illuminance: 230 mW / cm) from the outer surface side of the substrate using an ultraviolet irradiation device (Lintec Corporation, product name "RAD-2010m / 12"). 2 , Light intensity: 190mJ / cm 2 ) was performed to cure the first adhesive layer. Then, using a universal tensile tester (Shimadzu Corporation, product name "Autograph AG-IS"), the adhesive sheet for workpiece processing was peeled from the silicon wafer under peeling conditions of a peel angle of 180° and a peeling speed of 300 mm / min. The surface of the silicon wafer to which the adhesive sheet for workpiece processing had been attached was then visually observed, and adhesive residue was evaluated according to the following evaluation criteria. Evaluations A (◯) and B (△) indicate passing.

[0136] <Evaluation criteria> A(〇): No glue residue. B (△): Adhesive residue remains in part of the area where the adhesive sheet for workpiece processing was attached, but at a level that does not pose a problem in practical use. F(×): There is adhesive residue over the entire area where the adhesive sheet for workpiece processing was attached.

[0137] [Example 1] (1) Preparation of the first pressure-sensitive adhesive composition 62 parts by weight of n-butyl acrylate (BA), 10 parts by weight of methyl methacrylate (MMA), and 28 parts by weight of 2-hydroxyethyl acrylate (HEA) were polymerized by solution polymerization to obtain a (meth)acrylic acid ester copolymer. Subsequently, 2-methacryloyloxyethyl isocyanate (MOI) was added in an amount equivalent to 80 mol% of the 2-hydroxyethyl acrylate constituting the (meth)acrylic acid ester copolymer, and dibutyltin dilaurate (DBTDL) was added as a tin-containing catalyst in an amount of 0.025 parts by weight per 100 parts by weight of the (meth)acrylic acid ester copolymer. The mixture was then allowed to react at 50°C for 24 hours to obtain a (meth)acrylic acid ester copolymer (weight average molecular weight 500,000) with energy beam-curable groups introduced into the side chains.

[0138] 100 parts by mass (solids equivalent, the same applies below) of the (meth)acrylic acid ester copolymer obtained above with energy ray-curable groups introduced into the side chains, 0.188 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Tosoh Corporation, product name "Coronate L") as a crosslinker, and 1-hydroxycyclohexyl phenyl ketone (manufactured by IGM Resins BV, "Irgacure 184") as a photopolymerization initiator were mixed and diluted with toluene to obtain a coating solution of a first pressure-sensitive adhesive composition with a solids content of 30% by mass. The coating solution of the first pressure-sensitive adhesive composition is a coating solution for forming a first pressure-sensitive adhesive layer having energy ray curability.

[0139] (2) Preparation of the second adhesive composition 91 parts by mass of n-butyl acrylate (BA) and 9 parts by mass of acrylic acid (AA) were copolymerized to obtain a (meth)acrylic acid ester copolymer (weight average molecular weight: 700,000). 33.6 parts by mass of the obtained (meth)acrylic acid ester copolymer and 0.75 parts by mass of a composition containing trimethylolpropane-modified tolylene diisocyanate (TDI-TMP) as a crosslinking agent (Tosoh Corporation, Coronate L) were diluted with methyl ethyl ketone to obtain a coating liquid of a second pressure-sensitive adhesive composition with a solids content of 30% by mass. The coating liquid of the second pressure-sensitive adhesive composition is a coating liquid for forming a second pressure-sensitive adhesive layer that is not energy ray-curable.

[0140] (3) Fabrication of laminated sheets First, a laminate sheet was prepared by laminating a second pressure-sensitive adhesive layer on a substrate. A polyethylene terephthalate film (thickness: 188 μm) was prepared as the substrate. The coating liquid prepared in (2) Preparation of second pressure-sensitive adhesive composition above was applied to one side of the substrate and dried by heating, thereby forming a 5 μm-thick second pressure-sensitive adhesive layer on the polyethylene terephthalate film substrate. This resulted in a laminate sheet in which a 5 μm-thick second pressure-sensitive adhesive layer not having energy ray curability was laminated on a 188 μm-thick substrate.

[0141] (4) Preparation of adhesive sheets for workpiece processing Next, a pressure-sensitive adhesive sheet for workpiece processing was prepared. A release film was prepared, consisting of a 38 μm-thick polyethylene terephthalate film with a silicone-based release agent layer on one side. The coating liquid prepared in (1) Preparation of the First Pressure-Sensitive Adhesive Composition above was applied to the release surface of the release film and dried by heating, forming a 10 μm-thick first pressure-sensitive adhesive layer on the release film. The surface of the second pressure-sensitive adhesive layer (exposed surface of the second pressure-sensitive adhesive layer) of the laminate sheet prepared in (3) above was attached to the surface of the first pressure-sensitive adhesive layer opposite the release film side (exposed surface of the first pressure-sensitive adhesive layer), thereby obtaining the pressure-sensitive adhesive sheet for workpiece processing of Example 1. The obtained pressure-sensitive adhesive sheet for workpiece processing comprises a substrate, a second pressure-sensitive adhesive layer not having energy ray curability, and a first pressure-sensitive adhesive layer having energy ray curability, provided in this order.

[0142] The polarity value δ1 of the (meth)acrylic acid ester copolymer having an energy ray-curable group introduced into the side chain as the adhesive contained in the first adhesive layer was calculated using the above-mentioned formula (F1), and the polarity value δ2 of the (meth)acrylic acid ester copolymer as the adhesive contained in the second adhesive layer was calculated using the above-mentioned formula (F1). In addition, the absolute value |Δδ| of the difference between the polarity value δ1 and the polarity value δ2 was calculated.

[0143] In each example and each comparative example, in formula (F1), the proportion (mass%) of each monomer used in the synthesis of the (meth)acrylic acid ester copolymer having an energy ray-curable group introduced into the side chain for each adhesive, and the proportion (mass%) of each monomer used in the synthesis of the (meth)acrylic acid ester copolymer were substituted for A, and the values ​​shown in Table 1 below were substituted for M, Ei, and Vi for each monomer.

[0144] [Table 1]

[0145] [Example 2] The adhesive sheet for work processing of Example 2 was obtained in the same manner as in Example 1, except that the coating liquid of the second adhesive composition was changed to the coating liquid of the second adhesive composition described below.

[0146] 84 parts by weight of n-butyl acrylate (BA), 8 parts by weight of methyl methacrylate (MMA), 3 parts by weight of acrylic acid (AA), and 5 parts by weight of 2-hydroxyethyl acrylate (HEA) were copolymerized to obtain a (meth)acrylic copolymer (weight average molecular weight: 800,000). 40 parts by weight of the obtained (meth)acrylic copolymer and 0.185 parts by weight of a composition containing trimethylolpropane-modified tolylene diisocyanate (TDI-TMP) as a crosslinking agent (Tosoh Corporation, Coronate L) were mixed and diluted with toluene to obtain a coating solution of a second pressure-sensitive adhesive composition with a solids content of 30% by weight.

[0147] [Example 3] The adhesive sheet for work processing of Example 3 was obtained in the same manner as in Example 1, except that the coating liquid of the second adhesive composition was changed to the coating liquid of the second adhesive composition described below.

[0148] 84 parts by weight of n-butyl acrylate (BA), 10 parts by weight of methyl methacrylate (MMA), 1 part by weight of acrylic acid (AA), and 5 parts by weight of 2-hydroxyethyl acrylate (HEA) were copolymerized to obtain a (meth)acrylic copolymer (weight average molecular weight: 800,000). 40 parts by weight of the obtained (meth)acrylic copolymer and 0.185 parts by weight of a composition containing trimethylolpropane-modified tolylene diisocyanate (TDI-TMP) as a crosslinking agent (Tosoh Corporation, Coronate L) were mixed and diluted with toluene to obtain a coating solution of a second pressure-sensitive adhesive composition with a solids content of 30% by weight.

[0149] [Comparative Example 1] An adhesive sheet for work processing of Comparative Example 1 was obtained in the same manner as in Example 1, except that the coating liquid of the second adhesive composition was changed to the coating liquid of the second adhesive composition described below.

[0150] 80 parts by weight of 2-ethylhexyl acrylate (2EHA), 10 parts by weight of methyl methacrylate (MMA), and 10 parts by weight of 2-hydroxyethyl acrylate (HEA) were copolymerized to obtain a (meth)acrylic copolymer (weight average molecular weight: 600,000). 40 parts by weight of the obtained (meth)acrylic copolymer and 0.185 parts by weight of a composition containing trimethylolpropane-modified tolylene diisocyanate (TDI-TMP) as a crosslinking agent (Tosoh Corporation, Coronate L) were mixed and diluted with toluene to obtain a coating solution of a second pressure-sensitive adhesive composition with a solids content of 30% by weight.

[0151] Comparative Example 2 Except for not providing the second adhesive layer, an adhesive sheet for workpiece processing of Comparative Example 2 was obtained in the same manner as in Example 1. This adhesive sheet for workpiece processing comprises a substrate and a first adhesive layer having energy ray curability, provided in this order.

[0152] [Table 2]

[0153] The absolute value of the difference between the polarity value of the energy ray-curable adhesive contained in the first adhesive layer having energy ray-curability and the polarity value of the non-energy ray-curable adhesive contained in the second adhesive layer not having energy ray-curability is 1.00 (cal / cm 3 ) 0.5 The adhesive sheets for workpiece processing of each of the following Examples had good results in the keying evaluation, indicating that the energy ray-curable first adhesive layer prevented peeling from the substrate. Furthermore, the adhesive sheets for workpiece processing of each Example also had good results in the adhesive residue evaluation.

[0154] From the above results, it was confirmed that the adhesive sheet for workpiece processing according to this embodiment suppresses peeling between the substrate and the adhesive layer having energy ray curing properties, and also suppresses the occurrence of adhesive residue on the workpiece. [Explanation of symbols]

[0155] 10...substrate, 10A...first main surface (first main surface of substrate), 10B...second main surface (second main surface of substrate), 21...first adhesive layer, 21A...first main surface (first main surface of first adhesive layer), 21B...second main surface (second main surface of first adhesive layer), 22...second adhesive layer, 22A...first main surface (first main surface of second adhesive layer), 22B...second main surface (second main surface of second adhesive layer), 100...adhesive sheet for workpiece processing.

Claims

1. An adhesive sheet for workpiece processing, A substrate; a first pressure-sensitive adhesive layer having energy ray curability and provided on at least one surface of the substrate; a second pressure-sensitive adhesive layer that is not energy ray-curable and is provided between the substrate and the first pressure-sensitive adhesive layer; Equipped with the first pressure-sensitive adhesive layer contains an energy ray-curable pressure-sensitive adhesive, the second pressure-sensitive adhesive layer contains a non-energy ray-curable pressure-sensitive adhesive that does not have energy ray-curability, The absolute value of the difference between the polarity value of the non-energy ray-curable adhesive and the polarity value of the energy ray-curable adhesive is 1.00 (cal / cm ３ ) ０．５ Below is the Adhesive sheet for workpiece processing.

2. The adhesive sheet for workpiece processing according to claim 1, The polarity of the non-energy ray curable adhesive is 9.80 (cal / cm ３ ) ０．５ That's all. Adhesive sheet for workpiece processing.

3. The adhesive sheet for workpiece processing according to claim 1 or 2, the polarity of the energy ray-curable adhesive is greater than the polarity of the non-energy ray-curable adhesive; Adhesive sheet for workpiece processing.

4. The adhesive sheet for workpiece processing according to claim 1 or 2, The adhesive sheet for work processing is an adhesive sheet for semiconductor package processing. Adhesive sheet for workpiece processing.

5. The adhesive sheet for workpiece processing according to claim 1 or 2, The adhesive sheet for workpiece processing is a dicing sheet. Adhesive sheet for workpiece processing.

6. The adhesive sheet for workpiece processing according to claim 1 or 2, The non-energy ray curable pressure-sensitive adhesive is an acrylic pressure-sensitive adhesive. Adhesive sheet for workpiece processing.

7. The adhesive sheet for workpiece processing according to claim 6, The non-energy ray-curable pressure-sensitive adhesive contains a (meth)acrylic copolymer containing a structural unit derived from n-butyl acrylate in the largest amount. Adhesive sheet for workpiece processing.

8. The adhesive sheet for workpiece processing according to claim 7, The (meth)acrylic copolymer further contains a structural unit derived from acrylic acid. Adhesive sheet for workpiece processing.

9. The adhesive sheet for workpiece processing according to claim 1 or 2, The energy ray-curable pressure-sensitive adhesive is an acrylic pressure-sensitive adhesive. Adhesive sheet for workpiece processing.

10. The adhesive sheet for workpiece processing according to claim 9, the acrylic pressure-sensitive adhesive is a (meth)acrylic acid ester polymer having an energy ray-curable group introduced into a side chain thereof, and contains a (meth)acrylic acid ester copolymer containing a structural unit derived from n-butyl acrylate in the largest amount; Adhesive sheet for workpiece processing.

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