TW202101550A - Work processing sheet - Google Patents

Abstract

A work processing sheet for processing a work having an uneven structure on a surface, the sheet comprising a base material, an intermediate layer laminated on one surface side of the base material, and a pressure-sensitive adhesive layer laminated on the surface side of the intermediate layer opposite to the base material, wherein the intermediate layer has a storage elastic modulus at 25 DEG C lower than that of the pressure-sensitive adhesive layer at 25 DEG C, the intermediate layer has a thickness of 50-300 [mu]m (inclusive), and the work processing sheet has a bending resistance of 70 mm or less as measured by a cantilever method according to JIS L 1086:2007. Such a work processing sheet has an excellent embedding property and can suppress the generation of wrinkles during sticking.

Description

Sheets for workpiece processing

The present invention relates to a workpiece processing sheet suitable for use in the processing of workpieces such as semiconductor wafers, and particularly relates to a workpiece processing sheet suitable for use in the processing of a workpiece having an uneven structure on the surface.

In the manufacture of semiconductor devices, generally speaking, after forming a loop on the surface of the semiconductor wafer, the back surface of the semiconductor wafer is ground, the thickness of the semiconductor wafer is adjusted, and the semiconductor wafer is cut. The wafer undergoes a dicing step.

Incidentally, in recent years, with the diversification of manufactured semiconductor devices, workpieces with special structures and structures have become the aforementioned processing objects. As an example of such a workpiece, a workpiece having an uneven structure on the surface can be used.

For example, in response to the increase in capacity and functionality of electronic circuits in recent years, the development of multilayer circuits in which a plurality of semiconductor wafers are stacked three-dimensionally has been progressing. In this type of multilayer circuit, although the conductive connection of the semiconductor wafer is generally performed by wire bonding in the past, due to the necessity of miniaturization and high performance, the development is not wire bonding, but manufacturing with through-slave circuits For TSV wafers that form through electrodes (TSV) from the surface to the opposite surface, direct conductive connection between the upper and lower TSV wafers is an effective technique.

In order to realize the direct conductive connection between the above-mentioned TSV wafers, TSV wafers are usually provided in such a way that the end of the through electrode protrudes from the surface of the wafer, or the end of the through electrode is provided with a convex electrode (hereinafter, sometimes The protruding part of the through-electrode, the convex electrode provided at the end of the through-electrode, and the electrode provided in a protruding manner on the surface of the workpiece are collectively referred to as "bumps"). Such bumps are those that constitute the uneven structure on the surface of the wafer.

The wafer having bumps on the surface as described above can be obtained by dicing the wafer having bumps on the surface on a workpiece processing sheet and then dividing them into pieces. In this dicing, from the viewpoint of protecting the bumps, a workpiece processing sheet is attached to the surface of the wafer where the bumps exist. Therefore, in the sheet for processing a workpiece, it is required to have good embedding properties that can bury bumps existing on the surface of the workpiece.

For example, Patent Document 1 discloses a workpiece processing sheet assuming that a semiconductor wafer having bumps as described above is used as a workpiece. In particular, Patent Document 1 discloses that an absorption layer is provided between the base material and the adhesive layer from the viewpoint of achieving good embedment of bumps. [Prior Technical Literature] [Patent Literature]

Patent Document 1: Japanese Patent No. 6051302

[The problem to be solved by the invention]

Incidentally, when dicing a wafer using a workpiece processing sheet, the adhesive surface (hereinafter, sometimes referred to as "adhesive surface") of the workpiece processing sheet is attached to the wafer and the dicing frame on. The conventional sheet material for workpiece processing causes wrinkles when attached here, which adversely affects the cutting step and the expanding step performed thereafter.

The present invention was made in view of the above circumstances, and its object is to provide a sheet for workpiece processing that has excellent embedding properties while suppressing the occurrence of wrinkles at the time of attachment. [Means to solve the problem]

In order to achieve the above-mentioned object, first, the present invention provides a work-processing sheet comprising: a base material, an intermediate layer laminated on one side of the base material, and the intermediate layer laminated on the opposite side of the base material The adhesive layer on the side is used for processing workpieces with uneven structure on the surface. The storage modulus of the intermediate layer at 25°C is lower than that of the adhesive layer at 25°C. The thickness of the intermediate layer It is 50 μm or more and 300 μm or less, and the bending resistance of the above-mentioned workpiece processing sheet measured by the cantilever method based on JIS L1086:2007 is 70 mm or less (Invention 1).

The above-mentioned invention (Invention 1) related to the workpiece processing sheet, by providing an intermediate layer having the above-mentioned storage modulus and thickness between the base material and the adhesive layer, the uneven structure existing on the surface of the workpiece , Can exert excellent embedding. Furthermore, since the bending resistance of the work-processing sheet is within the above-mentioned range, the occurrence of wrinkles at the time of sticking can be well suppressed.

In the above invention (Invention 1), the storage modulus of the intermediate layer at 25°C is preferably 20 kPa or more lower than the storage modulus of the adhesive layer at 25°C (Invention 2).

In the above inventions (Inventions 1 and 2), the storage modulus of the intermediate layer at 25°C is preferably 10 kPa or more and 260 kPa or less (Invention 3).

In the above inventions (Inventions 1 to 3), the storage modulus of the adhesive layer at 25°C is preferably 50 kPa or more and 300 kPa or less (Invention 4).

In the above inventions (Inventions 1 to 4), the above-mentioned substrate is preferably composed of a polyolefin-based film (Invention 5).

In the above inventions (Inventions 1 to 5), the adhesive layer is preferably composed of an active energy ray-curable adhesive (Invention 6).

In the aforementioned inventions (Inventions 1 to 6), the aforementioned workpiece is preferably a workpiece having bumps on the surface (Invention 7).

In the above invention (Invention 7), the height of the bump is preferably 50 μm or more (Invention 8). [Effects of the invention]

The sheet for workpiece processing according to the present invention has excellent embedding properties and can suppress the occurrence of wrinkles during attachment.

Hereinafter, embodiments related to the present invention will be described. Fig. 1 is a cross-sectional view of a sheet for workpiece processing according to an embodiment of the present invention. The work processing sheet 1 according to this embodiment includes a base material 11, an intermediate layer 12 laminated on one side, and an adhesive layer 13 laminated on the side of the intermediate layer 12 opposite to the base material 11.

1. Constituents of sheets for workpiece processing (1) Substrate As the base material 11 in the present embodiment, there is nothing in particular as long as it can achieve the above-mentioned conditions regarding the bending resistance of the workpiece processing sheet 1 and at the same time exhibit the desired functions when the workpiece processing sheet 1 is used. limited.

In particular, the base material 11 is preferably a resin mold whose main material is a resin-based material. Specific examples thereof include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film, norbornene resin film, etc. Polyolefin-based film; polyester-based film such as polyethylene terephthalate film, polybutylene terephthalate film, and polyethylene naphthalate; ethylene-vinyl acetate copolymer film; ethylene- (Meth)acrylic acid copolymer film, ethylene-methyl (meth)acrylate copolymer film, other ethylene-(meth)acrylate copolymer film and other ethylene-based copolymer films; polyvinyl chloride film, vinyl chloride copolymer Polyvinyl chloride-based films such as material films; (meth)acrylate copolymer films; polyurethane films; polyimide films; polystyrene films; polycarbonate films; fluororesin films, etc. In addition, modified membranes such as cross-linked membranes and ionic polymer membranes can also be used. In addition, the base material 11 may be a laminated film formed by laminating a plurality of layers of the above-mentioned films. In this laminated film, the materials constituting each layer may be the same or different. In addition, in this specification, "(meth)acrylic acid" means both acrylic acid and methacrylic acid. The same applies to other similar terms.

As the base material 11 in this embodiment, from the viewpoint of easily satisfying the requirements of the bending resistance of the workpiece processing sheet 1, among the above-mentioned films, a polyolefin-based film is preferred, and a polyethylene film is particularly preferred. good. As a preferable example of a polyethylene film, a low density polyethylene (LDPE) film, a linear low density polyethylene (LLDPE) film, a high density polyethylene (HDPE) film, etc. are mentioned.

The base material 11 may also contain various additives such as flame retardants, plasticizers, antistatic agents, lubricants, antioxidants, colorants, infrared absorbers, ultraviolet absorbers, and ultraviolet absorbers. Although the content of these additives is not particularly limited, it is preferably a range in which the substrate 11 can exhibit desired functions.

On the surface of the base material 11 on which the intermediate layer 12 is laminated, in order to improve the adhesion with the intermediate layer 12, surface treatments such as primer treatment, corona treatment, and plasma treatment may be performed.

Although the thickness of the base material 11 may be appropriately selected according to the method of using the workpiece processing sheet 1, from the viewpoint of easily satisfying the bending resistance condition of the workpiece processing sheet 1, it is preferably 200 μm or less. In particular, it is preferably 150 μm or less. In addition, the thickness of the base material 11 is preferably 10 μm or more, and particularly preferably 25 μm or more, from the viewpoint that the workpiece processing sheet 1 easily has a strength that can withstand the processing of the workpiece.

(2) Adhesive layer As the adhesive constituting the adhesive layer 13 in this embodiment, as long as it can realize the storage modulus relationship between the intermediate layer 12 and the adhesive layer 13, and at the same time, it can exert sufficient adhesion to the workpiece for the processing of the workpiece. That is, it is not particularly limited.

For example, as examples of adhesives constituting the adhesive layer 13, acrylic adhesives, rubber-based adhesives, silicone-based adhesives, urethane-based adhesives, polyester-based adhesives, and polyvinyl ether-based adhesives can be cited.剂 etc. Among these, it is preferable to use an acrylic adhesive from the viewpoint that it is easy to exert a desired adhesive force and to adjust the storage modulus of the adhesive layer 13 easily.

In addition, although the adhesive constituting the adhesive layer 13 may be an adhesive that does not have active energy ray hardening properties, it may be an adhesive having active energy ray hardening properties (hereinafter, sometimes referred to as "active energy ray hardening adhesive Agent ") is better. Since the adhesive layer 13 is composed of an active energy ray-curable adhesive, the adhesive layer 13 is hardened by irradiation of the active energy ray, so that the adhesive force of the workpiece processing sheet 1 to the adherend can be reduced. In this way, the processed workpiece becomes easy to separate from the workpiece processing sheet 1.

The active energy ray curable adhesive constituting the adhesive layer 13 may be a polymer having active energy ray curability as the main component, or an active energy ray non-curable polymer (without active energy ray curable (A polymer) and a mixture of monomers and/or oligomers having at least one active energy ray-curable group as the main component.

First, the active energy ray-curable adhesive is a case where a polymer having active energy ray-curable properties is used as a main component, which will be described below.

A polymer having active energy ray-curable properties, in which a (meth)acrylate (co)polymer (A) having active energy ray-curable functional groups (active energy ray-curable groups) introduced into the side chain (hereinafter, It is sometimes referred to as "active energy ray-curable polymer (A)"). By using this active energy ray-curable polymer (A), when the work processing sheet 1 after the adhesive layer 13 is cured is separated from the adherend, it becomes easy to control the adhesive residue on the adherend. This active energy ray-curable polymer (A) is an acrylic copolymer (a1) having a functional group-containing monomer unit and an unsaturated group-containing compound (a2) having a functional group bonded to the functional group ) The winner is preferred.

As the above-mentioned functional group-containing monomer, a monomer having a polymerizable double bond in the molecule and a functional group such as a hydroxyl group, a carboxyl group, an amino group, an amido group, a benzyl group, and a glycidyl group is preferable. Among others, as the functional group, it is preferable to use a hydroxyl-containing monomer (a hydroxyl-containing monomer).

Examples of the above-mentioned hydroxyl-containing monomers include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and (meth) 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc. Among these, 2-hydroxyethyl acrylate is preferably used. Moreover, these can be used individually or in combination of 2 or more types.

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. These can be used alone or in combination of two or more kinds.

Examples of the above-mentioned amine group-containing monomers or amide group-containing monomers include, for example, aminoethyl (meth)acrylate, n-butylaminoethyl (meth)acrylate, and the like. These can be used alone or in combination of two or more kinds.

The acrylic copolymer (a1) preferably contains 3% by mass or more of the structural unit derived from the above-mentioned functional group-containing monomer, and particularly preferably contains 5% by mass or more. In addition, the acrylic copolymer (a1) preferably contains 30% by mass or less of the structural units derived from the above-mentioned functional group-containing monomer, particularly preferably 20% by mass or less, and further preferably contains 15% by mass or less Better. When the acrylic copolymer (a1) contains the functional group-containing monomer in the above range, it becomes easy to form the desired active energy ray-curable polymer (A).

The acrylic copolymer (a1) preferably contains an alkyl (meth)acrylate as a monomer unit constituting the acrylic copolymer (a1) from the viewpoint of easy formation of an adhesive having desired performance. As the alkyl (meth)acrylate, those having 1 to 18 carbon atoms in the alkyl group are preferred, and those having 1 to 4 carbon atoms are particularly preferred.

As specific examples of the aforementioned alkyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)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, (meth) ) Lauryl acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, etc. These can be used alone or in combination of two or more kinds. Among the above alkyl (meth)acrylates, it is preferable to use at least one of methyl (meth)acrylate and n-butyl (meth)acrylate, especially those using methyl acrylate and n-butyl acrylate At least one is preferred.

The acrylic copolymer (a1) preferably contains 60% by mass or more derived from the above alkyl (meth)acrylate, especially 70% by mass or more, and more preferably 80% by mass or more . In addition, the acrylic copolymer (a1) preferably contains 97% by mass or less derived from the above alkyl (meth)acrylate, particularly preferably 95% by mass or less, and further preferably contains 85% by mass or less Better. When the acrylic copolymer (a1) contains the alkyl (meth)acrylate in the above range, it becomes easy to form an adhesive having desired performance.

Acrylic copolymer (a1), together with the above-mentioned functional group-containing monomer and alkyl (meth)acrylate, may be copolymerized with other monomers.

Examples of the above-mentioned other monomers include, for example, methoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and (meth)acrylic acid. Alkoxyalkyl-containing (meth)acrylates such as ethoxyethyl; (meth)acrylates having aliphatic rings such as cyclohexyl (meth)acrylate; phenyl (meth)acrylates (Meth)acrylates with aromatic rings; N-(meth)acryloylmorpholine, N-vinyl-2-pyrrolidone, N-(meth)acryloylpyrrolidone, etc. Nitrogen heterocyclic monomers; (meth)acrylamide, N,N-dimethyl (meth)acrylamide and other non-crosslinkable acrylamide; (meth)acrylic acid N,N-di Non-crosslinkable (meth)acrylates with tertiary amino groups such as methylaminoethyl and N,N-dimethylaminopropyl (meth)acrylate; vinyl acetate; styrene, etc. .

The polymerization state of the acrylic copolymer (a1) may be a random copolymer or a block copolymer. In addition, there is nothing special about the polymerization method, and the polymerization can be carried out by a general polymerization method, for example, a solution polymerization method.

By reacting the above-mentioned acrylic copolymer (a1) having a functional group-containing monomer unit with an unsaturated group-containing compound (a2) having a functional group bonded to the functional group, active energy rays can be obtained Curing polymer (A).

The functional group of the unsaturated group-containing compound (a2) can be appropriately selected according to the type of the functional group of the functional group-containing monomer unit of the acrylic copolymer (a1). For example, when the functional group of the acrylic copolymer (a1) is a hydroxyl group, an amino group, or an amide group, the functional group of the unsaturated group-containing compound (a2) is preferably an isocyanate group or an epoxy group. When the functional group of the acrylic copolymer (a1) is a glycidyl group, the functional group of the unsaturated group-containing compound (a2) is preferably an amino group, a carboxyl group, or an aziridin group.

In addition, in the above-mentioned unsaturated group-containing compound (a2), the active energy ray-polymerizable carbon-carbon double bond contains at least one per molecule, preferably 1 to 6, and more preferably 1 to 4 . As specific examples of the unsaturated group-containing compound (a2), for example, 2-methacryloyloxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate , Methacrylic isocyanate, allyl isocyanate, 1,1-(bisacryloxymethyl) ethyl isocyanate; by diisocyanate compound or polyisocyanate compound, and (meth) hydroxyethyl acrylate Acrylic monoisocyanate compound obtainable by reaction; Acrylic monoisocyanate compound obtained by reacting diisocyanate compound or polyisocyanate compound with polyol compound and hydroxyethyl (meth)acrylate; (methyl) Glycidyl acrylate; (meth)acrylic acid, 2-(1-aziridinyl)ethyl (meth)acrylate, 2-vinyl-2-oxazoline, 2-isopropenyl-2-㗁Oxazoline etc.

The unsaturated group-containing compound (a2) may be used in a ratio of 50 mol% or more relative to the number of moles of the functional group-containing monomer of the acrylic copolymer (a1), especially 60 mol%. More than ear% is preferable, and more than 70 mol% is more preferable. In addition, the above-mentioned unsaturated group-containing compound (a2) is preferably used in a ratio of 95 mol% or less to the number of moles of the functional group-containing monomer of the above-mentioned acrylic copolymer (a1), especially It is preferably 93 mol% or less, and more preferably 90 mol% or less.

In the reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2), it corresponds to the combination of the functional group of the acrylic copolymer (a1) and the functional group of the unsaturated group-containing compound (a2) , The reaction temperature, pressure, solvent, time, presence or absence of catalyst, and type of catalyst can be appropriately selected. In this way, the functional group present in the acrylic copolymer (a1) reacts with the functional group in the unsaturated group-containing compound (a2) to introduce the unsaturated group into the side of the acrylic copolymer (a1) Chain, an active energy ray-curable polymer (A) can be obtained.

The weight average molecular weight (Mw) of the active energy ray-curable polymer (A) thus obtained is preferably 10,000 or more, particularly preferably 150,000 or more, and more preferably 200,000 or more. In addition, the weight average molecular weight (Mw) is preferably 1.5 million or less, particularly preferably 1 million or less, and further preferably 800,000 or less. In addition, the weight average molecular weight (Mw) in this specification is a value in terms of standard polystyrene measured by gel permeation chromatography (GPC method).

When the active energy ray-curable adhesive contains active energy ray-curable polymer (A) as the main component, the active energy ray-curable adhesive may further contain active energy Radiation-curable monomers and/or oligomers (B).

As the active energy ray-curable monomer and/or oligomer (B), for example, an ester of a polyol and (meth)acrylic acid can be used.

Examples of the active energy ray-curable monomer and/or oligomer (B) include monofunctional acrylates such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate. Class, trimethylolpropane tri(meth)acrylate, neopentaerythritol tri(meth)acrylate, neopentaerythritol tetra(meth)acrylate, dineopentaerythritol hexa(meth)acrylate Esters, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dimethylol tricyclic Polyfunctional acrylates such as decane di(meth)acrylate, polyester oligo(meth)acrylate, urethane oligo(meth)acrylate, etc.

For the active energy ray curable polymer (A), when the active energy ray curable monomer and/or oligomer (B) are formulated, the active energy ray curable monomer in the active energy ray curable adhesive And/or the content of the oligomer (B) is preferably more than 0 parts by mass relative to 100 parts by mass of the active energy ray-curable polymer (A), particularly preferably 60 parts by mass or more. In addition, the content is preferably 250 parts by mass or less with respect to 100 parts by mass of the active energy ray-curable polymer (A), particularly preferably 200 parts by mass or less.

Here, when ultraviolet rays are used as active energy rays for curing the active energy ray-curable adhesive, it is preferable to add a photopolymerization initiator (C). By using the photopolymerization initiator (C), the polymerization curing time and the amount of light irradiation can be reduced.

Specific examples of the photopolymerization initiator (C) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin Isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, benzoin dimethyl ketal, 2,4-diethyl thioxanthone (2,4-diethyl thioxanthone), 1-hydroxy ring Hexyl phenyl ketone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, bibenzyl, biacetyl, β-chloride Anthraquinone, (2,4,6-trimethylbenzyldiphenyl) phosphine oxide, 2-benzothiazole-N,N-diethyldithiocarbamate, oligo{2-hydroxy- 2-Methyl-1-[4-(1-propenyl)phenyl]acetone}, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-hydroxy-1 -{4-[4-(2-Hydroxy-2-methyl-propanyl)-benzyl]phenyl}-2-methyl-propan-1-one and the like. Among these, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propanyl)-benzyl]phenyl}-2-methyl-propan-1-one Better. These can be used alone or in combination of two or more kinds.

The photopolymerization initiator (C) is relative to the active energy ray curable polymer (A) (when an active energy ray curable monomer and/or oligomer (B) is prepared, the active energy ray curable polymer The total amount of the substance (A) and active energy ray-curable monomer and/or oligomer (B) (100 parts by mass)) 100 parts by mass, preferably 1 part by mass or more, especially 0.5 parts by mass or more Better. In addition, the photopolymerization initiator (C) is relative to the active energy ray hardenable polymer (A) (when active energy ray hardenable monomers and/or oligomers (B) are prepared, the active energy ray hardenable polymer The total amount of the polymer (A) and the active energy ray-curable monomer and/or oligomer (B) (100 parts by mass)) 100 parts by mass, preferably 10 parts by mass or less, especially 6 parts by mass or less The amount is better.

In the active energy ray-curable adhesive, other suitable components may be blended in addition to the above-mentioned components. Examples of other components include active energy ray non-curable polymer components or oligomer components (D), crosslinking agents (E), and the like.

Examples of the active energy ray non-curable polymer component or oligomer component (D) include, for example, polyacrylate, polyester, polyurethane, polycarbonate, polyolefin, etc., with a weight average molecular weight (Mw) of 3000 ~2.5 million polymers or oligomers are preferred. By blending the component (D) in an active energy ray-curable adhesive, the adhesiveness and peelability before curing, the strength after curing, the adhesion to other layers, storage stability, etc. can be improved. The compounding amount of the component (D) is not particularly limited, and it is appropriately determined in the range of more than 0 parts by mass and 50 parts by mass or less with respect to 100 parts by mass of the active energy ray-curable polymer (A).

From the viewpoint that it is easy to adjust the storage modulus of the adhesive layer 13 in a desired range, it is preferable to use the crosslinking agent (E). As the crosslinking agent (E), a polyfunctional compound having reactivity with a functional group possessed by the active energy ray-curable polymer (A) or the like can be used. Examples of such polyfunctional compounds include isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, oxazoline compounds, and metal alkoxides. Compounds, metal chelate compounds, metal salts, ammonium salts, reactive phenol resins, etc.

The compounding amount of the crosslinking agent (E) is preferably 0.01 parts by mass or more, and particularly preferably 0.1 parts by mass or more, relative to 100 parts by mass of the active energy ray curable polymer (A). In addition, the compounding amount of the crosslinking agent (E) is preferably 10 parts by mass or less, and particularly preferably 5 parts by mass or less, relative to 100 parts by mass of the active energy ray curable polymer (A).

Next, for the case where the active energy ray curable adhesive is a mixture of an active energy ray non-curable polymer component and a monomer and/or oligomer having at least one active energy ray curable group as the main component , The following is an explanation.

As the active energy ray non-curable polymer component, for example, the same component as the above-mentioned acrylic copolymer (a1) can be used.

As the monomer and/or oligomer having at least one active energy ray-curable group, the same as the above-mentioned component (B) can be selected. The blending ratio of the active energy ray non-curable polymer component and the monomer and/or oligomer having at least one active energy ray hardenable group is relative to 100 parts by mass of the active energy ray non-curable polymer component, The monomer and/or oligomer having at least one active energy ray-curable group is preferably 1 part by mass or more, particularly preferably 60 parts by mass or more. In addition, the blending ratio is based on 100 parts by mass of the active energy ray non-curable polymer component, and the monomer and/or oligomer having at least one active energy ray-curable group is 200 parts by mass or less. Preferably, it is particularly preferably 160 parts by mass or less.

Even in this case, it is the same as the above, and the photopolymerization initiator (C) and the crosslinking agent (E) can be appropriately formulated.

The storage modulus of the adhesive layer 13 at 25° C. is preferably 50 kPa or more, especially 70 kPa or more, and more preferably 100 kPa or more. Since the storage modulus of the adhesive layer 13 at 25°C is 50kPa or more, compared to the storage modulus of the adhesive layer 13 at 25°C, it is easier to meet the storage modulus of the intermediate layer 12 at 25°C. Low relationship. In addition, the storage modulus of the adhesive layer 13 at 25° C. is preferably 300 kPa or less, especially 200 kPa or less, and further preferably 150 kPa or less. When the storage modulus is 300 kPa or less, the work processing sheet 1 according to the present embodiment can easily exhibit better embedding properties in the uneven structure. In addition, in this specification, the storage modulus of the adhesive layer 13 at 25°C means that even if the adhesive layer 13 is composed of an active energy ray-curable adhesive, the adhesive layer 13 is irradiated with the active energy ray. The measured storage modulus at 25°C. The details of the measurement method of this storage modulus are as described in the following test example.

The thickness of the adhesive layer 13 is preferably 5 μm or more, especially 10 μm or more, and further preferably 15 μm or more. When the thickness of the adhesive layer 13 is 5 μm or more, the workpiece processing sheet 1 according to this embodiment can easily exhibit desired adhesiveness. In addition, the thickness of the adhesive layer 13 is preferably 60 μm or less, particularly preferably 45 μm or less, and further preferably 30 μm or less. When the thickness of the adhesive layer 13 is 60 μm or less, the sheet 1 for workpiece processing can easily satisfy the condition of bending resistance. In addition, since the thickness of the adhesive layer 13 is 60 μm or less, when the adherend is separated from the cured adhesive layer 13, it becomes easy to separate.

(3) Middle layer The intermediate layer 12 in the present embodiment is not particularly limited as long as the storage modulus relationship between the intermediate layer 12 and the adhesive layer 13 can be achieved. As the material constituting the intermediate layer 12, it is preferable to use a specific resin from the standpoint of easily achieving conditions related to the storage modulus, and from the standpoint of ease of manufacture, the intermediate layer 12 is made of an adhesive. The one is better.

As the adhesive for forming the intermediate layer 12, the above-mentioned adhesives for forming the adhesive layer 13 can be used. Here, since the intermediate layer 12 will not be directly attached to the workpiece, it is not necessary to consider the ease of peeling the workpiece after processing. From this point of view, the adhesive used to form the intermediate layer 12 is preferably an adhesive that does not have active energy ray curability.

As an adhesive which does not have active energy ray curability as an adhesive used for the intermediate layer 12, the same components as the above-mentioned acrylic copolymer (a1) can be used. Here, in the acrylic copolymer (a1), the content of the structural unit derived from the functional group-containing monomer and the alkyl (meth)acrylate may be the same as the content in the adhesive layer 13.

In addition, the adhesive used to form the intermediate layer 12 preferably contains the crosslinking agent (E). The blending amount of the crosslinking agent (E) at this time can be the same as the blending amount in the adhesive layer 13 .

In the sheet 1 for workpiece processing according to the present embodiment, the storage modulus of the intermediate layer 12 at 25°C is lower than the storage modulus of the adhesive layer 13 at 25°C. In this way, the workpiece processing sheet 1 can maintain the performance of the adhesive layer 13 such as resistance to workpiece adhesion within a desired range, and at the same time, it can exhibit good embedding of the uneven structure in the workpiece having uneven structure on the surface. Entrants. From this point of view, it is better that the storage modulus of the intermediate layer 12 at 25°C is lower than the storage modulus of the adhesive layer 13 at 25°C by 20 kPa or more, especially 30 kPa or more, and more preferably 40 kPa or more. .

The storage modulus of the intermediate layer 12 at 25°C is preferably 260 kPa or less, particularly preferably 160 kPa or less, and further preferably 70 kPa or less. Since the storage modulus of the intermediate layer 12 at 25° C. is 260 kPa or less, the aforementioned storage modulus relationship between the intermediate layer 12 and the adhesive layer 13 can be easily achieved. In addition, the storage modulus of the intermediate layer 12 at 25°C is preferably 10 kPa or more, particularly 20 kPa or more, and further preferably 30 kPa or more. When the storage modulus is 10 kPa or more, the sheet 1 for processing a workpiece according to the present embodiment can easily satisfy the condition regarding bending resistance. In addition, the details of the method for measuring the storage modulus are as described in the above test example.

In the workpiece processing sheet 1 according to this embodiment, the thickness of the intermediate layer 12 is 50 μm or more, preferably more than 50 μm, particularly preferably 70 μm or more, and more preferably 100 μm or more. When the thickness of the intermediate layer 12 is 50 μm or more, even a workpiece having a concave-convex structure with a relatively large height difference can exhibit good embedding properties. In addition, the thickness of the intermediate layer 12 is preferably 300 μm or less. When the thickness of the intermediate layer 12 is 300 μm or less, when the sheet 1 for workpiece processing is used, the components constituting the intermediate layer 12 can be effectively suppressed from oozing out of the intermediate layer 12, and the workpiece can be processed favorably.

In addition, the total thickness of the intermediate layer 12 and the thickness of the adhesive layer 13, from the viewpoint of easy to exhibit good embedding properties, the workpiece processing sheet 1 related to this embodiment is present in the workpiece used The thickness of the convex portion of the concavo-convex structure on the part is preferably 1.2 times or more, and more preferably 2 times or more. In addition, the thickness of the intermediate layer 12 is preferably thicker than the thickness of the adhesive layer 13 from the viewpoint of easily exhibiting good embedding properties.

(4) Peel the sheet The workpiece processing sheet 1 related to this embodiment protects the surface of the adhesive layer 13 on the opposite side of the intermediate layer 12 (hereinafter, sometimes referred to as "adhesive surface") to the workpiece. For the purpose of noodles, it is easy to peel off the sheet in this area. The configuration of the release sheet is arbitrary, and the plastic film is subjected to release treatment with a release agent or the like as an example. Specific examples of plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyamides such as polypropylene and polyethylene. Olefin film. As the release agent, silicone-based, fluorine-based, long-chain alkane-based, etc. can be used. Among these, silicone-based products that can provide stable performance at low cost are preferred. The thickness of the release sheet is not particularly limited, but it is usually 20 μm or more and 250 μm or less.

2. Physical properties of sheets for workpiece processing The sheet 1 for workpiece processing according to this embodiment has a bending resistance of 70 mm or less as measured by the cantilever method based on JIS L1086:2007. Since the bending resistance is 70 mm or less, the work processing sheet 1 according to this embodiment can well suppress the occurrence of wrinkles during use. Generally speaking, a workpiece processing sheet is cut according to the shape of an attached object (for example, a wafer and a frame), and then attached to the attached object. Such a cut sheet for workpiece processing is prone to wrinkles when it is attached. In particular, wrinkles are more likely to occur at locations near the attachment end than at locations near the attachment start end on the attachment target. Therefore, according to the workpiece processing sheet 1 according to this embodiment, even the wrinkles can be suppressed satisfactorily. From such a viewpoint, the above-mentioned bending resistance is preferably 50 mm or less, and particularly preferably 40 mm or less.

In addition, in the sheet 1 for processing a workpiece according to the present embodiment, the above-mentioned bending resistance is preferably 10 mm or more. With the above-mentioned bending resistance of 10 mm or more, in the workpiece processing sheet 1 attached to the attachment target, deformation due to the influence of tension becomes less likely to occur, and as a result, it is easy to achieve an uneven structure. Better embedding. In addition, since the above-mentioned bending resistance is 10 mm or more, the workability of the sheet 1 for workpiece processing becomes better. In addition, the details of the above-mentioned bending resistance measurement method are as described in the following test examples.

3. Manufacturing method of sheet for workpiece processing The manufacturing method of the sheet 1 for workpiece processing concerning this embodiment is not specifically limited. As a preferable manufacturing method, a laminate of the base material 11 and the intermediate layer 12 is prepared, and the laminate of the adhesive layer 13 and the release sheet is prepared, and then attached so that the intermediate layer 12 contacts the adhesive layer 13 The method of combining these laminates.

The formation of the above-mentioned two types of laminates can be performed by a known method. For example, a coating liquid containing an adhesive composition for forming the intermediate layer 12, and a solvent or a dispersing medium as necessary is prepared, and the coating liquid is applied to one side of the substrate 11 to form a coating film , The coating film is dried to form the intermediate layer 12. In this way, a laminate of the base material 11 and the intermediate layer 12 can be obtained. In addition, a coating liquid containing an adhesive composition for forming the adhesive layer 13 and a solvent or a dispersion medium as necessary is prepared, and the coating liquid is applied to the release surface of the release sheet to form a coating film , The coating film is dried to form the adhesive layer 13. In this way, a laminate of the adhesive layer 13 and the release sheet can be obtained.

As mentioned above, the coating of the coating liquid can be carried out by known methods, for example, bar coating, knife coating, roll coating, knife coating, die coating, gravure coating Coating method etc. are carried out. In addition, the characteristics of the coating liquid are not particularly limited as long as it can be applied, and the components used to form the intermediate layer 11 or the adhesive layer 13 may be contained as a solute or as a dispersant. In addition, the release sheet can be peeled off as a process material, and it can also protect the adhesive layer 13 during the time it is attached to the workpiece.

When the adhesive composition used to form the adhesive layer 13 contains the cross-linking agent (E), it can be activated by changing the drying conditions (temperature, time, etc.) mentioned above, or by additionally providing heat treatment. The cross-linking reaction between the energy ray-curable polymer (A) and the cross-linking agent (E) progresses, and it is preferable to form a cross-linked structure in the adhesive layer 13 at a desired density. The same applies when the adhesive composition for forming the intermediate layer 12 contains a crosslinking agent (E), and it is preferable that the crosslinking reaction of the acrylic copolymer (a1) and the crosslinking agent (E) in the coating film proceeds. In addition, in order to fully advance the crosslinking reaction, after bonding the above-mentioned two types of laminates, for example, so-called maturation of standing for several days in an environment at 23° C. and a relative humidity of 50% may be performed.

4. How to use sheets for workpiece processing The workpiece processing sheet 1 according to the present embodiment can be used for processing a workpiece having an uneven structure on the surface. That is, after the adhesive surface of the workpiece processing sheet 1 according to the present embodiment is attached to the surface where the uneven structure exists in the workpiece, the workpiece can be processed on the workpiece processing sheet 1. In response to processing, the workpiece processing sheet 1 related to this embodiment can be used as a back grinding sheet, a dicing sheet, an expanding sheet, a pick-up sheet, and the like.

Here, according to the workpiece processing sheet 1 according to the present embodiment, as described above, the occurrence of wrinkles in the workpiece processing sheet 1 when the adhesive surface is attached to the workpiece can be favorably suppressed. Therefore, according to the workpiece processing sheet 1 according to the present embodiment, steps such as cutting and spreading can be performed well.

In addition, the workpiece processing sheet 1 according to the present embodiment, as described above, can exhibit excellent embedding properties with respect to the uneven structure existing on the surface of the workpiece. Therefore, according to the workpiece processing sheet 1 according to the present embodiment, the uneven structure can be protected while performing desired processing. Examples of workpieces processed using the workpiece processing sheet 1 according to the present embodiment include semiconductor wafers with uneven structures on the surface, semiconductor members such as semiconductor packages, and glass members such as glass plates. In addition, as an example of the above-mentioned concavo-convex structure, bumps, particularly convex electrodes, can be cited. The workpiece processing sheet 1 according to this embodiment is particularly suitable for use in the processing of TSV wafers provided with through electrodes.

Here, although the shape and position of the bumps in the workpiece having bumps on the surface are not particularly limited, the height of the bumps may be 50 μm or more, especially 50 μm or more, and further 70 μm or more. According to the workpiece processing sheet 1 according to this embodiment, even for such a relatively high bump, it can still exhibit good embedding properties.

When the processing of the workpiece on the workpiece processing sheet 1 according to the present embodiment is completed, and the processed workpiece is separated from the workpiece processing sheet 1, the workpiece in the workpiece processing sheet 1 is separated before the separation. It is preferable that the adhesive layer 13 is irradiated with active energy rays. In this way, the adhesive layer 13 is hardened, the adhesive force of the workpiece processing sheet 1 with respect to the processed workpiece is reduced well, and the separation of the processed workpiece becomes easy.

As the above-mentioned active energy rays, for example, electromagnetic waves or charged particle rays having an energy quantum can be used. Specifically, ultraviolet rays, electron rays, etc. can be used. Especially the ultraviolet light which is easy to handle is preferred. Ultraviolet rays can be irradiated by high-pressure mercury lamps, xenon lamps, LEDs, etc. The irradiance of ultraviolet rays is preferably 50 mW/cm ² or more and 1000 mW/cm ² or less. Further, the light amount of 50mJ / cm ² or more preferably, in particular in 80mJ / cm ² or more preferably, is further 200mJ / cm ² or more is preferable. In addition, the amount of light is preferably 10000 mJ/cm ² or less, particularly preferably 5000 mJ/cm ² or less, and more preferably 2000 mJ/cm ² or less. On the other hand, electron beam irradiation can be performed by an electron beam accelerator or the like, and the irradiation amount of electron beam is preferably 10 krad or more and 1000 krad or less.

The embodiments described above are described to facilitate the understanding of the present invention, and are not intended to limit the present inventors. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents within the technical scope of the present invention.

For example, another layer may be interposed between the substrate 11 and the intermediate layer 12 on the surface of the substrate 11 opposite to the intermediate layer 12. [Example]

Hereinafter, although the present invention will be further specifically described with examples and the like, the scope of the present invention is not limited to these examples and the like.

[Example 1] (1) Production of substrate The low-density polyethylene was extruded by a small T-die extruder (manufactured by Toyo Seiki Seisakusho, product name "LABO PLASTOMILL") to obtain a base material with a thickness of 70 μm. The bending resistance of this substrate alone was measured in the same manner as in Test Example 2 below, and it was 19 mm.

(2) Preparation of adhesive composition for intermediate layer 70 parts by mass of n-butyl acrylate, 20 parts by mass of methyl acrylate, and 10 parts by mass of 2-hydroxyethyl acrylate were polymerized by a solution polymerization method to obtain a (meth)acrylate polymer. The weight average molecular weight (Mw) of this acrylic polymer was measured by the following method and was 650,000.

100 parts by mass of the acrylic polymer obtained above, and 0.13 parts by mass of trimethylolpropane modified phenylene diisocyanate (manufactured by Tosoh Corporation, product name "Coronate L") as a crosslinking agent in a solvent They are mixed to obtain a coating liquid of the adhesive composition for an intermediate layer.

(3) Preparation of adhesive composition for adhesive layer 83 parts by mass of n-butyl acrylate, 10 parts by mass of methyl acrylate, and 7 parts by mass of 2-hydroxyethyl acrylate were polymerized by a solution polymerization method to obtain a (meth)acrylate polymer. This (meth)acrylate polymer is reacted with methacryloxyethyl isocyanate (MOI) having a molar number of 80 mol% relative to the 2-hydroxyethyl acrylate of the acrylic copolymer , To obtain an acrylic polymer having an active energy ray-curable group introduced into the side chain. The weight average molecular weight (Mw) of this acrylic polymer was measured by the following method and was 650,000.

100 parts by mass of the acrylic polymer having active energy ray-curable groups introduced into the side chain obtained above, as a photopolymerization initiator, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl) -Propyl-propanyl)-benzyl]phenyl}-2-methyl-propan-1-one (manufactured by BASF, product name "Omnirad 127") 3 parts by mass, trimethylolpropane as a crosslinking agent 0.43 parts by mass of modified phenylmethylene diisocyanate (manufactured by Tosoh Corporation, product name "Coronate L") was mixed in a solvent to obtain a coating liquid of an adhesive composition for an adhesive layer.

(4) Formation of the intermediate layer For the single side of the substrate prepared in the above step (1), apply the coating liquid of the adhesive composition for the intermediate layer prepared in the above step (2), and heat it to dry, and on the substrate An intermediate layer with a thickness of 150 μm is formed. In this way, a first laminate formed by laminating the base material and the intermediate layer was obtained.

(5) Formation of adhesive layer For a release sheet made by forming a silicone-based release agent layer on one side of a 38μm thick polyethylene terephthalate (PET) film (manufactured by LINTEC, product name "SP-PET381031") On the peeling surface of, apply the coating liquid of the adhesive composition and dry it by heating to form an adhesive layer with a thickness of 20 μm on the peeling sheet. In this way, a second laminate formed by laminating the adhesive layer and the release sheet was obtained.

(6) Production of adhesive sheets for workpiece processing By bonding the surface on the intermediate layer side of the first laminate obtained in the above step (4) and the surface on the adhesive layer side of the second laminate obtained in the above step (5), Obtain a sheet for workpiece processing.

Here, the above-mentioned weight average molecular weight (Mw) is the weight average molecular weight of the converted standard polystyrene measured (GPC measurement) using gel permeation chromatography (GPC) under the following conditions. >Measurement conditions> ・Measurement device: HLC-8320 manufactured by Tosoh Corporation ・GPC string (pass in the following order): Tosoh Corporation TSK gel superH-H TSK gel superHM-H TSK gel SuperH2000 ・Measuring solvent: Tetrahydrofuran ・Measurement temperature: 40°C

[Examples 2 to 6, Comparative Examples 1 to 3] Except that the type and thickness of the base material and the thickness of the intermediate layer were changed as described in Table 1, the same procedure as in Example 1 was carried out to produce a sheet for workpiece processing.

[Test Example 1] (Measurement of Storage Modulus) The adhesive composition for the intermediate layer prepared in the examples and comparative examples was applied to a base film made of polyethylene terephthalate with a thickness of 38 μm and a silicone-based release agent formed on one side The release surface of the release sheet (manufactured by LINTEC Corporation: SP-PET381031) composed of layers was dried by heating to form an intermediate layer with a thickness of 40 μm on the release sheet. A plurality of laminates of the intermediate layer and the release sheet thus obtained are prepared.

Using the above-mentioned laminate, it was bonded until the intermediate layer had a thickness of 800 μm, and the obtained interlayer laminate was punched into a circle with a diameter of 10 mm to measure the viscoelasticity of the intermediate layer. Then, with a viscoelasticity measuring device (manufactured by TA Instruments Japan Inc., product name "ARES"), the above-mentioned sample was deformed at a frequency of 1 Hz, and the storage modulus at -50 to 150°C was measured to obtain a storage at 25°C. The value of the modulus (kPa). The results are shown in Table 1 as the storage modulus of the intermediate layer.

In addition, except that the adhesive composition for the intermediate layer was substituted for the adhesive composition for the adhesive layer prepared in the examples and comparative examples, the storage in the adhesive layer at 25°C was measured in the same manner as above. Modulus (kPa). The results are shown in Table 1 as the storage modulus of the adhesive layer.

[Test Example 2] (Measurement of bending resistance) Regarding the workpiece processing sheets manufactured in the Examples and Comparative Examples, the bending resistance was measured by the cantilever method based on JIS L1086:2007. Specifically, after cutting the workpiece processing sheets manufactured in the Examples and Comparative Examples into a size of 2 cm×15 cm, the peeling sheet was peeled and removed to obtain a measurement sample. The measurement sample was placed on the platform of the 45° cantilever tester so that the adhesive layer side of the measurement sample was facing upward. Then, the measurement sample was slid in the direction of the inclined plane of the 45° cantilever tester at a constant speed. Record the amount of sliding (mm) when the measuring sample is bent and contacts the inclined surface. This measurement was performed 5 times using different samples, and the average value was calculated. The average value is shown in Table 1 as bending resistance (mm).

[Test Example 3] (Evaluation of Wrinkles) The exposed surface of the adhesive layer exposed by peeling the release sheet from the workpiece processing sheets manufactured in the Examples and Comparative Examples was attached to the silicon wafer and the dicing frame. These operations use a wafer placement machine (manufactured by LINTEC, product name "RAD-2510F/12"), under the conditions of attaching pressure: 0.2MPa, attaching speed: 20mm/s, and attaching temperature: 40℃ get on.

After sticking, visually confirm whether wrinkles (especially wrinkles at the sticking terminal portion) have occurred on the workpiece processing sheet. Then, based on the following criteria, the occurrence of wrinkles was evaluated. ○: No wrinkles occurred. ×: Wrinkles occurred.

[Test Example 4] (Evaluation of Implantability) Prepare bump wafer 1 with bumps on the surface: 30μm, bump pitch: 100μm, bump height: 20μm, and bump diameter: 100μm, bump pitch: 200μm, bump height on the surface : Bump wafer 2 with 80μm bumps.

The exposed surface of the adhesive layer exposed by peeling the release sheet from the workpiece processing sheets manufactured in the examples and comparative examples was attached to the bump wafer 1 and the bump wafer 2 respectively. The face of the block. The attaching at this time is to use the adhesive sheet attaching device for wafer protection (manufactured by LINTEC, product name "RAD-3510F/12"), under the conditions of attaching temperature: 40°C and attaching speed: 5mm/s get on.

Then, the bubbles around the bumps of the bump wafer after the adhesive sheet was attached were observed with an optical microscope. Based on the following criteria, the bumping wafer 1 and the bump wafer 2 were evaluated for the embedding of the bumps. Entry. The results are shown in Table 1. ○: It is confirmed that there are almost no bubbles in contact with adjacent bubbles (the bubbles exist independently of each other). △: Although it was confirmed that there were bubbles in contact with some of the adjacent bubbles, there were almost no bubbles in contact with all the adjacent bubbles (some of the bubbles were in contact). ×: Almost all bubbles are in contact with all adjacent bubbles (bubbles are in contact with each other).

In addition, the details of the abbreviations described in Table 1 are as follows. [Substrate] LDPE: Low-density polyethylene as a base material by extrusion PET: Polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name "COSMOSHINE A4100") EMAA: Ethylene-methacrylic acid copolymer (manufactured by Dow-Mitsui Polychemicals Company, Ltd., product name "NUCREL N0903HC") was extruded and subjected to electron beam irradiation (exposure amount: 110kGy, number of irradiation times: Once, the irradiated surface: the surface in contact with the intermediate layer) the obtained substrate.

[Table 1] Substrate middle layer Adhesive layer Bending resistance (mm) Evaluation of wrinkles Embeddedness evaluation species Thickness (μm) Thickness (μm) Storage modulus (kPa) Thickness (μm) Storage modulus (kPa) Bump wafer 1 (bump height: 20μm) Bump wafer 2 (bump height: 80μm) Example 1 LDPE 70 150 43 20 114 twenty one ○ ○ ○ Example 2 PET 50 150 43 20 114 43 △ ○ ○ Example 3 LDPE 70 80 43 20 114 twenty three ○ ○ ○ Example 4 LDPE 70 50 43 20 114 twenty four ○ ○ × Example 5 LDPE 140 150 43 20 114 50 ○ ○ ○ Example 6 EMAA 80 150 43 20 114 25 ○ ○ ○ Comparative example 1 LDPE 70 20 43 20 114 twenty three ○ × × Comparative example 2 PET 75 150 43 20 114 75 × ○ ○ Comparative example 3 PET 100 150 43 20 114 Above 100 × ○ ○

It is clear from Table 1 that the workpiece processing sheet according to the example has excellent embedding properties for bumps, and can well suppress the occurrence of wrinkles at the time of attachment. [Industry Availability]

The sheet for workpiece processing according to the present invention is suitable for use as a cutting sheet for workpieces having an uneven structure on the surface.

1: Sheet for workpiece processing 11: Substrate 12: Middle layer 13: Adhesive layer

[Fig. 1] A cross-sectional view of a sheet for workpiece processing according to an embodiment of the present invention.

1: Sheet for workpiece processing

11: Substrate

12: Middle layer

13: Adhesive layer

Claims (8)

A sheet material for workpiece processing, which has: A base material, an intermediate layer laminated on one side of the base material, and an adhesive layer laminated on the side opposite to the base material in the intermediate layer, and the workpiece processing sheet is used to provide an uneven structure on the surface The workpiece is processed, The storage modulus of the intermediate layer at 25°C is lower than the storage modulus of the adhesive layer at 25°C, The thickness of the intermediate layer is 50μm or more and 300μm or less, The bending resistance of the above-mentioned workpiece processing sheet measured by the cantilever method based on JIS L1086:2007 is 70 mm or less. The sheet for workpiece processing according to claim 1, wherein the storage modulus of the intermediate layer at 25°C is 20 kPa or more lower than the storage modulus of the adhesive layer at 25°C. The sheet for workpiece processing according to claim 1, wherein the storage modulus of the intermediate layer at 25° C. is 10 kPa or more and 260 kPa or less. The sheet for workpiece processing according to claim 1, wherein the storage modulus of the adhesive layer at 25°C is 50 kPa or more and 300 kPa or less. The workpiece processing sheet according to claim 1, wherein the base material is composed of a polyolefin-based film. The workpiece processing sheet according to claim 1, wherein the adhesive layer is composed of an active energy ray-curable adhesive. The sheet for workpiece processing according to claim 1, wherein the workpiece is a workpiece having bumps on the surface. The workpiece processing sheet according to claim 7, wherein the height of the bumps is 50 μm or more.

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