KR102579051B1 - Manufacturing method of sheet for work processing and processed work - Google Patents

Abstract

A sheet for work processing comprising a base material and an adhesive layer, wherein the adhesive layer is composed of an active energy ray-curable adhesive, the water contact angle of the adhesive layer is 50° or more and 80° or less, adhesive force F1 to a silicon wafer, and After the work processing sheet was immersed in distilled water at 23°C for 12 hours and dried at 23°C for 24 hours, the adhesion to the silicon wafer F2 was measured.
Decrease rate of adhesion (%) = {(F1-F2)/F1} × 100
A sheet for work processing with a reduction rate of adhesion calculated from 20% to 50%. This sheet for work processing suppresses the intrusion of water at the interface between the work processing sheet and the cut material or the obtained chip, while retaining the adhesive derived from the adhesive layer attached to the cut material during processing of the cut material such as a semiconductor wafer. It can be easily removed from the cutting object by running water.

Description

Manufacturing method of sheet for work processing and processed work

The present invention relates to a work processing sheet that can be suitably used for dicing, and a method of manufacturing a processed work using the work processing sheet.

Semiconductor wafers of silicon, gallium arsenide, etc. and various packages (hereinafter, these may be collectively referred to as “cutting objects”) are manufactured in a large-diameter state, and these are small device pieces. (Hereinafter, it may be referred to as a “chip.”) After being cut (diced) and individually separated (picked up), it is transferred to the next process, the mount process. At this time, the cut object, such as a semiconductor wafer, is attached to a work processing sheet provided with a base material and an adhesive layer, and is provided to each process of dicing, cleaning, drying, expanding, pickup, and mounting. do.

In the above-described dicing process, the dicing blade, the object to be cut, and the sheet for work processing are heated by frictional heat generated between the rotating dicing blade and the object to be cut or the sheet for work processing. Additionally, in the dicing process, cutting pieces may be generated from the object to be cut or the sheet for work processing and may adhere to the object to be cut.

For this reason, when performing a dicing process, flowing water is usually supplied to the cut portion to cool the dicing blade, etc., and at the same time, the resulting cutting pieces are removed from the object to be cut.

In Patent Document 1, for the purpose of promoting the removal of cutting pieces by flowing water, the contact angle of the surface opposite to the substrate in the adhesive layer before ultraviolet irradiation with pure water is 82° to 114°, and further, methylene iodide A sheet for work processing is disclosed that has a contact angle of 44° to 64° and a probe tack test peak value of 294 to 578 kPa in the adhesive layer before ultraviolet irradiation.

Patent Document 1: Japanese Patent No. 5019657

However, when performing a dicing process using the conventional sheet for work processing disclosed in Patent Document 1, the adhesive derived from the adhesive layer of the sheet for work processing could not be sufficiently removed from the cut object.

Additionally, generally, due to the supply of flowing water during dicing, water may enter the interface between the work processing sheet and the object to be cut, or the interface between the work processing sheet and the obtained chip. If such water intrudes, there is a possibility that chip blowing or chip damage may occur.

The present invention was made in consideration of this actual situation, and suppresses the intrusion of water at the interface between the work processing sheet and the cut object or the interface between the work processing sheet and the obtained chip, while preventing the above-mentioned water from entering during processing of the cut object such as a semiconductor wafer. The purpose is to provide a sheet for work processing that allows the adhesive derived from the adhesive layer attached to the cut workpiece to be well removed from the workpiece to be cut by running water, and a method for manufacturing a processed workpiece using the workpiece processing sheet. Do it as

In order to achieve the above object, the first invention is a workpiece processing sheet comprising a base material and an adhesive layer laminated on one side of the base material, wherein the adhesive layer is composed of an active energy ray-curable adhesive, , the water contact angle of the surface of the adhesive layer opposite to the substrate is 50° or more and 80° or less, the adhesive force of the workpiece processing sheet to the silicon wafer is F1, and the workpiece processing sheet is placed in distilled water at 23° C. After being immersed in for 12 hours and dried at 23° C. for 24 hours, when the adhesion of the work processing sheet to the silicon wafer is set to F2, the following formula (1)

Decrease rate of adhesion (%) = {(F1-F2)/F1} × 100... (One)

A sheet for work processing is provided, wherein the reduction rate of adhesive force calculated from is 20% or more and 50% or less (invention 1).

In the sheet for work processing according to the invention (invention 1), the water contact angle described above is in the above range, and the reduction rate of the adhesive force described above is within the range, so that the interface between the sheet for work processing and the object to be cut, or the sheet for processing the work and the obtained Intrusion of water at the chip interface is suppressed. In addition, since the above-mentioned water contact angle is within the above range, the adhesive constituting the adhesive layer has a predetermined affinity for water, and at the same time, because the above-mentioned reduction rate of adhesive force is within the above range, the adhesive attached to the cut object is When the adhesive force is appropriately reduced by contact with water, the adhesive adhering to the cut object can be successfully removed with flowing water.

In the above invention (invention 1), the adhesive force F1 is preferably 1000 mN/25 mm or more and 10000 mN/25 mm or less (invention 2).

In the above inventions (inventions 1 and 2), the adhesive force F2 is preferably 900 mN/25 mm or more and 8000 mN/25 mm or less (invention 3).

In the above inventions (inventions 1 to 3), the active energy ray-curable adhesive includes methyl acrylate, 2-methoxyethyl (meth)acrylate, ethyl carbitol (meth)acrylate, and (meth)acrylic acid as monomer units constituting the polymer. It is preferable that the adhesive is formed from an adhesive composition containing an acrylic copolymer containing at least one type selected from methoxyethylene glycol (Invention 4).

In the above inventions (inventions 1 to 4), it is preferable that it is a dicing sheet (invention 5).

The second present invention is a bonding process of bonding a workpiece to a surface opposite to the base material in the adhesive layer of the workpiece processing sheet (inventions 1 to 5), and bonding the workpiece to the workpiece processing sheet. A processing step of obtaining a processed work laminated on the work processing sheet, irradiating the adhesive layer with active energy rays to cure the adhesive layer, and forming an adhesive force of the work processing sheet to the processed work. A method for manufacturing a machined work is provided, comprising an irradiation step for reducing , and a separation step for separating the machined work from the work sheet after irradiation with active energy rays (invention 6).

The work processing sheet related to the present invention suppresses the intrusion of water at the interface between the work processing sheet and the cut object or the interface between the work processing sheet and the obtained chip, while processing the cut material such as a semiconductor wafer. The adhesive derived from the adhesive layer adhered to can be well removed from the cut object with flowing water. Additionally, according to the manufacturing method of the machined work related to the present invention, the machined work can be efficiently manufactured.

Hereinafter, embodiments of the present invention will be described.

[Sheet for work processing]

The sheet for work processing according to the present embodiment includes a base material and an adhesive layer laminated on one side of the base material.

1. Physical properties of sheet for work processing

In the sheet for work processing according to the present embodiment, the water contact angle of the adhesive layer on the side opposite to the base material (hereinafter sometimes referred to as “adhesive surface”) is 50° or more and 80° or less. When this water contact angle is within the above range, the adhesive layer exhibits appropriate affinity for water, and when the work processing sheet is used for dicing the workpiece to be cut, the interface between the workpiece processing sheet and the workpiece to be cut, or the workpiece processing sheet. While suppressing the intrusion of water into the interface between the obtained chips, the adhesive derived from the adhesive layer adhering to the cut object can be successfully removed with flowing water. In addition, in this specification, the water contact angle means that the water contact angle is measured before the active energy ray is irradiated to the work processing sheet.

On the other hand, if the water contact angle is less than 50°, the pressure-sensitive adhesive layer exhibits excessive affinity for water and cannot suppress water intrusion, resulting in chip blowing or chip damage during dicing. In addition, if the water contact angle exceeds 80°, the affinity for water of the adhesive constituting the adhesive layer becomes insufficient, and the adhesive adhering to the cut object cannot be sufficiently removed with flowing water.

From the above viewpoint, the water contact angle is preferably 55° or more, and particularly preferably 60° or more. Additionally, the water contact angle is preferably 75° or less, and particularly preferably 70° or less. In addition, the details of the water contact angle measurement method described above are as described in the test examples described later.

In addition, in the work processing sheet according to the present embodiment, the adhesion of the work processing sheet to the silicon wafer is set to F1, the work processing sheet is immersed in distilled water at 23 ° C. for 12 hours, and dried at 23 ° C. for 24 hours, When the adhesion of the work processing sheet to the silicon wafer is set to F2, the following equation (1)

Decrease rate of adhesion (%) = {(F1-F2)/F1} × 100... (One)

The reduction rate of adhesive force calculated from is 20% or more and 50% or less. Since the reduction rate of this adhesive force is within the above range, when the adhesive layer is exposed to flowing water supplied to the cutting portion in the dicing process, the adhesive layer exhibits appropriate adhesive force to the cut object, and the sheet for work processing and the cutting material are While suppressing the intrusion of water into the interface of the cut object or the interface between the sheet for work processing and the obtained chip, the adhesive derived from the adhesive layer adhering to the cut object can be successfully removed with flowing water. In addition, in this specification, both the adhesive force F1 and the adhesive force F2 are adhesive forces measured before active energy rays are irradiated to the sheet for work processing.

On the other hand, if the reduction rate of the above-mentioned adhesive force is less than 20%, even after the adhesive derived from the adhesive layer is exposed to flowing water, the adhesive force of the adhesive to the cut object is maintained, so that the adhesive attached to the cut object can be exposed to flowing water. It becomes impossible to sufficiently remove it. In addition, if the reduction rate of the above-mentioned adhesive strength exceeds 50%, the adhesive force of the adhesive layer to the cut object decreases excessively, and the cut object or the resulting chip cannot be held well on the adhesive layer, resulting in damage to the cut object. Peeling may occur, or chip flying or chip damage may occur during dicing.

From this viewpoint, it is preferable that the reduction rate of the above-mentioned adhesive force is 23% or more. In addition, it is preferable that the reduction rate of the above-mentioned adhesive force is 40% or less.

In the sheet for work processing according to the present embodiment, the above-mentioned adhesive force F1 is preferably 1000 mN/25 mm or more, especially 2000 mN/25 mm or more, and further preferably 3000 mN/25 mm or more. Additionally, the adhesive force F1 is preferably 10000 mN/25 mm or less, and particularly preferably 7000 mN/25 mm or less.

In addition, in the workpiece processing sheet according to the present embodiment, the above-mentioned adhesive force F2 is preferably 900 mN/25 mm or more, especially 1500 mN/25 mm or more, and further preferably 2000 mN/25 mm or more. . Additionally, the adhesive force F2 is preferably 8000 mN/25 mm or less, and particularly preferably 5000 mN/25 mm or less.

Since the adhesive force F1 and the adhesive force F2 are each in the above range, it becomes easy to adjust the reduction rate of the adhesive force to the above-mentioned range. Details of the measuring method for adhesive force F1 and adhesive force F2 are as described in the test examples described later.

2. Components of sheet for work processing

(1) Description

In the work processing sheet according to the present embodiment, the base material exhibits a desired function in the use process of the work processing sheet, and preferably exhibits good permeability to active energy rays irradiated for curing of the adhesive layer. There is no particular limitation as long as it is done.

For example, the base material is preferably a resin film based on a resin-based material, and specific examples include ethylene-vinyl acetate copolymer film; Ethylene-based copolymer films such as ethylene-(meth)acrylic acid copolymer film, ethylene-(meth)acrylic acid copolymer film, and other ethylene-(meth)acrylic acid ester copolymer films; Polyolefin-based films such as polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film, and norbornene resin film; Polyvinyl chloride-based films such as polyvinyl chloride film and vinyl chloride copolymer film; Polyester-based films such as polyethylene terephthalate film, polybutylene terephthalate film, and polyethylene naphthalate; (meth)acrylic acid ester copolymer film; polyurethane film; polyimide film; polystyrene film; polycarbonate film; A fluororesin film, etc. can be mentioned. Examples of polyethylene films include low-density polyethylene (LDPE) films, linear low-density polyethylene (LLDPE) films, and high-density polyethylene (HDPE) films. Additionally, these crosslinked films and modified films called ionomer films are also used. In addition, the base material may be a laminated film formed by laminating multiple films described above. In this laminated film, the materials constituting each layer may be of the same type or may be of different types. As a substrate, among the above films, it is preferable to use an ethylene-methyl methacrylate copolymer film from the viewpoint of excellent flexibility. In addition, “(meth)acrylic acid” in this specification means both acrylic acid and methacrylic acid. The same goes for other similar terms.

The base material may contain various additives such as a flame retardant, a plasticizer, an antistatic agent, a lubricant, an antioxidant, a colorant, an infrared absorber, an ultraviolet ray absorber, and an ion trap. The content of these additives is not particularly limited, but is preferably within a range that allows the base material to exhibit the desired function.

The surface of the substrate on which the adhesive layer is laminated may be subjected to surface treatment such as primer treatment, corona treatment, or plasma treatment in order to increase adhesion to the adhesive layer.

The thickness of the base material can be appropriately set depending on the method in which the sheet for work processing is used, but is usually preferably 20 μm or more, and particularly preferably 25 μm or more. Additionally, the thickness is generally preferably 450 μm or less, and particularly preferably 300 μm or less.

(2) Adhesive layer

In the work processing sheet according to the present embodiment, the adhesive layer is composed of an active energy ray-curable adhesive, and at the same time exhibits the desired adhesive force to the object to be cut, and the work processing sheet has the reduction rate of the water contact angle and adhesive force described above. There is no particular limitation as long as it can be achieved. The adhesive layer is composed of an active energy ray-curable adhesive, and when separating the adhesive surface from the cut material adhered to the adhesive surface of the adhesive layer, the adhesive layer is cured by irradiation of active energy rays, forming a sheet for work processing. Adhesion to the object to be cut may be reduced. This makes it easy to separate the adhesive surface of the adhesive layer from the object to be cut.

The active energy ray curable adhesive constituting the adhesive layer may be composed mainly of a polymer with active energy ray curable properties, and may contain an active energy ray non-curable polymer (polymer that does not have active energy ray curable properties) and at least one active energy ray curable adhesive. It may be composed as a main component of a mixture of monomers and/or oligomers having a pre-curable group. Additionally, it may be a mixture of a polymer curable by active energy rays and a polymer non-curable by active energy rays. Additionally, it may be a mixture of a polymer having active energy ray curability and a monomer and/or oligomer having at least one active energy ray curable group. Additionally, it may be a mixture of a polymer having active energy ray curability, a polymer not curable by active energy ray, and a monomer and/or oligomer having at least one active energy ray curable group.

First, the case where the active energy ray-curable adhesive contains a polymer having active energy ray curability as the main component will be described below.

The polymer having active energy ray curing property is a (meth)acrylic acid ester (co)polymer (A) (hereinafter referred to as “active energy ray curing polymer (A)” into which a functional group (active energy ray curing group) having active energy ray curing property is introduced into the side chain. )”, it is preferable. This active energy ray-curable polymer (A) is preferably obtained by reacting an 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.

The acrylic copolymer (a1) preferably contains a monomer for adjusting the hydrophilicity of the acrylic copolymer (a1) (hereinafter sometimes referred to as a “hydrophilicity adjusting monomer”) as a monomer unit constituting the polymer. , particularly, as specific examples thereof, selected from methyl acrylate, 2-methoxyethyl (meth)acrylate, ethyl (meth)acrylate carbitol (ethoxyethoxyethyl (meth)acrylate), and methoxyethylene glycol (meth)acrylate. It is preferable to include at least one type. This monomer can improve the hydrophilicity of the acrylic copolymer (a1), thereby making it easier to adjust the water contact angle and the reduction rate of the adhesive force in the formed adhesive layer to the above-mentioned range. From the viewpoint of easy to obtain such effects, the acrylic copolymer (a1) contains at least one of methyl acrylate, 2-methoxyethyl acrylate, and methoxyethylene glycol acrylate among the above-mentioned monomers as monomer units constituting the polymer. It is desirable.

When the acrylic copolymer (a1) contains methyl acrylate as a monomer unit constituting the polymer, the content of methyl acrylate is preferably 10% by mass or more, especially 20% by mass or more, and further preferably 30% by mass or more. desirable. Additionally, the content of methyl acrylate is preferably 85% by mass or less. With this content, it becomes easier to adjust the reduction rate of the water contact angle and adhesive force in the formed adhesive layer to the above-mentioned range. In addition, in this specification, the content (% by mass) of methyl acrylate described above means the content with respect to all monomers constituting the acrylic copolymer (a1). In addition, the content (% by mass) of other monomers described later shall mean the content relative to all monomers constituting the acrylic copolymer (a1).

In addition, when the acrylic copolymer (a1) contains 2-methoxyethyl acrylate as a monomer unit constituting the polymer, the content of 2-methoxyethyl acrylate is preferably 10% by mass or more, especially 20% by mass or more. It is preferable, and it is also preferable that it is 30 mass % or more. Moreover, the content of 2-methoxyethyl acrylate is preferably 85% by mass or less, especially preferably 80% by mass or less, and further preferably 70% by mass or less. With this content, it becomes easier to adjust the reduction rate of the water contact angle and adhesive force in the formed adhesive layer to the above-mentioned range.

In addition, when the acrylic copolymer (a1) contains both methyl acrylate and 2-methoxyethyl acrylate as monomer units constituting the polymer, the total content of methyl acrylate and 2-methoxyethyl acrylate is 10. It is preferable that it is 30 mass % or more, and it is especially preferable that it is 50 mass % or more. Additionally, the total value is preferably 90% by mass or less, and particularly preferably 85% by mass or less. When the total value is within this range, it becomes easier to adjust the reduction rate of the water contact angle and adhesive force in the formed adhesive layer to the above-mentioned range.

In addition, when the acrylic copolymer (a1) contains methoxyethylene glycol acrylate as a monomer unit constituting the polymer, the content of methoxyethylene glycol acrylate is preferably 10% by mass or more, and particularly preferably 30% by mass or more. . Additionally, the content of methoxyethylene glycol acrylate is preferably 85% by mass or less, and particularly preferably 80% by mass or less. With this content, it becomes easier to adjust the reduction rate of the water contact angle and adhesive force in the formed adhesive layer to the above-mentioned range.

The acrylic copolymer (a1) preferably contains, in addition to the hydrophilicity adjustment monomer described above, 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 thereof.

The functional group-containing monomer as a structural unit of the acrylic copolymer (a1) is preferably a monomer having a polymerizable double bond and a functional group such as a hydroxy group, carboxyl group, amino group, substituted amino group, or epoxy group in the molecule.

Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylic acid, 2-hydroxypropyl (meth)acrylic acid, 3-hydroxypropyl (meth)acrylic acid, 2-hydroxybutyl (meth)acrylic acid, Examples include 3-hydroxybutyl (meth)acrylic acid, 4-hydroxybutyl (meth)acrylic acid, etc., and these are used individually or in combination of two 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 may be used individually, or two or more types may be used in combination.

Examples of amino group-containing monomers or substituted amino group-containing monomers include aminoethyl (meth)acrylate, n-butylaminoethyl (meth)acrylate, and the like. These may be used individually, or two or more types may be used in combination.

The acrylic copolymer (a1) preferably contains 1% by mass or more of structural units derived from the functional group-containing monomer, particularly preferably 5% by mass or more, and further preferably contains 10% by mass or more. . Furthermore, the acrylic copolymer (a1) preferably contains 35% by mass or less of structural units derived from the functional group-containing monomer, and especially preferably contains 30% by mass or less.

The (meth)acrylic acid ester monomer constituting the acrylic copolymer (a1) includes, in addition to (meth)acrylic acid alkyl ester with an alkyl group having 1 to 20 carbon atoms, for example, a monomer having an alicyclic structure in the molecule (alicyclic structure) containing monomer) is preferably used.

The (meth)acrylic acid alkyl esters include, in particular, (meth)acrylic acid alkyl esters in which the alkyl group has 1 to 18 carbon atoms, such as methyl methacrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and (meth)acrylic acid. n-butyl, 2-ethylhexyl (meth)acrylate, etc. are preferably used. These may be used individually or in combination of two or more types.

Monomers containing an alicyclic structure include, for example, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, adamantyl (meth)acrylate, isobornyl (meth)acrylate, and dicyclophene (meth)acrylate. Tenyl, dicyclopentenyloxyethyl (meth)acrylate, etc. are preferably used. These may be used individually or in combination of two or more types.

In addition, the acrylic copolymer (a1) preferably contains 50% by mass or more of structural units derived from (meth)acrylic acid ester monomer or a derivative thereof, particularly preferably 60% by mass or more, and further 70% by mass. It is desirable to contain the above. In addition, the acrylic copolymer (a1) preferably contains 99% by mass or less of structural units derived from (meth)acrylic acid ester monomer or a derivative thereof, and especially preferably contains 95% by mass or less, and It is preferable to contain it at 90% by mass or less.

The acrylic copolymer (a1) can preferably be obtained by copolymerizing the above-mentioned hydrophilicity adjusting monomer, a functional group-containing monomer, and (meth)acrylic acid ester monomer or a derivative thereof by a conventional method. In addition to these monomers, dimethylacrylamide may be used. , vinyl formate, vinyl acetate, styrene, etc. may be copolymerized.

An active energy ray-curable polymer (A) is obtained by reacting the acrylic copolymer (a1) having the above functional group-containing monomer unit with an unsaturated group-containing compound (a2) having a functional group bonded to the functional group.

The functional group of the unsaturated group-containing compound (a2) can be appropriately selected depending on the type of 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 hydroxy group, amino group, or substituted amino group, the functional group of the unsaturated group-containing compound (a2) is preferably an isocyanate group or an epoxy group, and the acrylic copolymer (a1) When the functional group possessed is an epoxy group, the functional group possessed by the unsaturated group-containing compound (a2) is preferably an amino group, a carboxyl group, or an aziridinyl group.

In addition, the unsaturated group-containing compound (a2) contains at least one, preferably 1 to 6, more preferably 1 to 4 active energy ray polymerizable carbon-carbon double bonds per molecule. Specific examples of such unsaturated group-containing compound (a2) include, for example, 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, and allyl isocyanate. , 1,1-(bisacryloyloxymethyl)ethyl isocyanate; Acryloyl monoisocyanate compounds obtained by reaction of diisocyanate compounds or polyisocyanate compounds with hydroxyethyl (meth)acrylate; Acryloyl monoisocyanate compounds obtained by reaction of a diisocyanate compound or polyisocyanate compound, a polyol compound, and hydroxyethyl (meth)acrylate; (meth)glycidyl acrylate; (meth)acrylic acid, 2-(1-aziridinyl)ethyl (meth)acrylic acid, 2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline, etc.

The unsaturated group-containing compound (a2) is preferably 50 mol% or more, particularly preferably 60 mol% or more, and more preferably 70 mol%, relative to the mole number of the functional group-containing monomer of the acrylic copolymer (a1). It is used at a rate of % or more. In addition, the unsaturated group-containing compound (a2) is preferably 95 mol% or less, particularly preferably 93 mol% or less, more preferably 93 mol% or less, relative to the mole number of the functional group-containing monomer of the acrylic copolymer (a1). It is used in a ratio of 90 mol% or less.

In the reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2), the temperature, pressure, and solvent of the reaction depend on the combination of the functional group of the acrylic copolymer (a1) and the functional group of the unsaturated group-containing compound (a2). , time, presence or absence of catalyst, and type of catalyst can be appropriately selected. As a result, the functional group present in the acrylic copolymer (a1) reacts with the functional group in the unsaturated group-containing compound (a2), and the unsaturated group is introduced into the side chain of the acrylic copolymer (a1), resulting in the active energy ray-curable polymer (A). 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 further preferably 200,000 or more. In addition, the weight average molecular weight (Mw) is preferably 1.5 million or less, and especially 1 million or less. In addition, the weight average molecular weight (Mw) in this specification is a standard polystyrene conversion value measured by gel permeation chromatography (GPC method).

Even when the active energy ray-curable adhesive is mainly composed of a polymer with active energy ray-curable property called an active energy ray-curable polymer (A), the active energy ray-curable adhesive is an active energy ray-curable monomer and/or oligomer (B). ) may contain more.

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

Such active energy ray-curable monomers and/or oligomers (B) include, for example, monofunctional acrylic acid esters such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate, and trimethylolpropane tri(meth)acrylate. ) Acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol Multifunctional acrylic acid esters such as di(meth)acrylate, polyethylene glycol di(meth)acrylate, dimethylol tricyclodecane di(meth)acrylate, polyester oligo(meth)acrylate, polyurethane oligo(meth)acrylate Acrylates, etc. can be mentioned.

When mixing an active energy ray curable monomer and/or oligomer (B) with an active energy ray curable polymer (A), the amount of active energy ray curable monomer and/or oligomer (B) in the active energy ray curable adhesive is The content is preferably more than 0 parts by mass, and especially preferably 60 parts by mass or more, based on 100 parts by mass of the active energy ray-curable polymer (A). Moreover, the content is preferably 250 parts by mass or less, and especially preferably 200 parts by mass or less, based on 100 parts by mass of the active energy ray-curable polymer (A).

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

The photopolymerization initiator (C) specifically includes benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, and benzoin methyl benzoate. , benzoin dimethyl ketal, 2,4-diethyl thioxanthone, 1-hydroxycyclohexylphenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, di Acetyl, β-chloroanthraquinone, (2,4,6-trimethyl benzyl diphenyl) phosphine oxide, 2-benzothiazole-N, N-diethyldithiocarbamate, oligo{2-hydroxy -2-methyl-1-[4-(1-propenyl)phenyl]propanone}, 2,2-dimethoxy-1,2-diphenylethan-1-one, etc. are mentioned. These may be used individually, or two or more types may be used together.

The photopolymerization initiator (C) is an active energy ray-curable polymer (A) (when blending an active energy ray-curable monomer and/or oligomer (B), the active energy ray-curable polymer (A) and the active energy ray-curable monomer (B). and/or 100 parts by mass of the total amount of the oligomer (B). It is preferably used in an amount of 0.1 parts by mass or more, especially 0.5 parts by mass or more. In addition, the photopolymerization initiator (C) is an active energy ray-curable polymer (A) (in the case of blending an active energy ray-curable monomer and/or oligomer (B), the active energy ray-curable polymer (A) and the active energy ray-curable polymer (A). It is preferably used in an amount of 10 parts by mass or less, especially 6 parts by mass or less, per 100 parts by mass of the total amount of monomer and/or oligomer (B) (100 parts by mass).

In an active energy ray-curable adhesive, in addition to the above components, other components may be blended as appropriate. Other components include, for example, an active energy ray non-curable polymer component or oligomer component (D), a crosslinking agent (E), etc.

Examples of the active energy ray non-curable polymer component or oligomer component (D) include polyacrylic acid ester, polyester, polyurethane, polycarbonate, polyolefin, etc., and have a weight average molecular weight (Mw) of 3000. ~2.5 million polymers or oligomers are preferred. By mixing the component (D) into an active energy ray-curable adhesive, the adhesiveness and peelability before curing, the strength after curing, adhesion to other layers, storage stability, etc. can be improved. The compounding amount of the component (D) is not particularly limited and 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).

As the crosslinking agent (E), a polyfunctional compound that has reactivity with the functional group of the active energy ray-curable polymer (A) or the like can be used. Examples of such multifunctional compounds 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 phenol resins. etc. can be mentioned.

The compounding amount of the crosslinking agent (E) is preferably 0.01 parts by mass or more, and especially preferably 3 parts by mass or more, with respect to 100 parts by mass of the active energy ray-curable polymer (A). Moreover, the compounding amount of the crosslinking agent (E) is preferably 20 parts by mass or less, and especially preferably 17 parts by mass or less, with respect to 100 parts by mass of the active energy ray-curable polymer (A).

Next, the case where the active energy ray-curable adhesive mainly contains 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 will be described below.

As the active energy ray non-curable polymer component, for example, a component similar to the acrylic copolymer (a1) described above can be used.

As the monomer and/or oligomer having at least one active energy ray-curable group, the same monomer and/or oligomer as the above-mentioned component (B) can be selected. The mixing ratio 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, with respect to 100 parts by mass of the active energy ray non-curable polymer component, having at least one active energy ray curable group. It is preferable that the monomer and/or oligomer is 1 part by mass or more, and it is especially preferable that it is 60 parts by mass or more. In addition, the mixing ratio is preferably 200 parts by mass or less of the monomer and/or oligomer having at least one active energy ray-curable group, and particularly preferably 160 parts by mass or less, per 100 parts by mass of the active energy ray non-curable polymer component. .

In this case as well, the photopolymerization initiator (C) and the crosslinking agent (E) can be appropriately mixed as described above.

The thickness of the adhesive layer is preferably 1 μm or more, and more preferably 5 μm or more. Additionally, the thickness is preferably 50 μm or less, and is preferably 40 μm or less. When the thickness of the adhesive layer is within the above range, it becomes easy to achieve the reduction rate of the adhesive force described above.

(3) Release sheet

In the sheet for work processing according to the present embodiment, a release sheet may be laminated on the adhesive surface of the adhesive layer for the purpose of protecting the adhesive surface until the adhesive surface is attached to the cutting object. The configuration of the release sheet is arbitrary, and an example is one in which a plastic film has been subjected to a release treatment using a release agent or the like. Specific examples of plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. As the release agent, silicone-based, fluorine-based, long-chain alkyl-based, etc. can be used, and among these, silicone-based because it is inexpensive and provides stable performance is preferable. There is no particular limitation on the thickness of the release sheet, but it is usually 20 μm or more and 250 μm or less.

(4) Other absences

In the sheet for work processing according to the present embodiment, an adhesive layer may be laminated on the adhesive surface of the adhesive layer. In this case, the sheet for work processing according to the present embodiment is provided with an adhesive layer as described above and can be used as a dicing/die bonding sheet. In such a sheet for work processing, a cut material is attached to the side of the adhesive layer opposite to the adhesive layer, and the adhesive layer is diced together with the cut material to obtain a chip in which the separated adhesive layers are laminated. You can. The chip can be easily fixed to the object on which the chip is mounted by this separate adhesive layer. As the material constituting the above-mentioned adhesive layer, it is preferable to use a material containing a thermoplastic resin and a low molecular weight thermosetting adhesive component, or a material containing a B stage (semi-cured burn) thermosetting adhesive component.

In addition, in the sheet for work processing according to the present embodiment, a protective film forming layer may be laminated on the adhesive surface of the adhesive layer. In this case, the workpiece processing sheet according to this embodiment can be used as a protective film forming and dicing sheet. In such a sheet for work processing, a cut object is affixed to the side of the protective film forming layer opposite to the adhesive layer, and the protective film forming layer is diced together with the cut object to obtain a chip on which the separated protective film forming layer is laminated. You can. As the above-mentioned cutting object, it is preferable to use one on which a circuit is formed on one side, and in this case, a protective film forming layer is usually laminated on the side opposite to the side on which the above-mentioned circuit is formed. By curing the separated protective film forming layer at a predetermined timing, a protective film with sufficient durability can be formed into a chip. The protective film forming layer is preferably made of an uncured curable adhesive.

In addition, the sheet for work processing according to the embodiment of the present application satisfies the reduction rate of the water contact angle and adhesive force described above. However, when the adhesive layer or protective film forming layer described above is laminated on the adhesive layer, the adhesive layer before such layer is laminated. For , it is good as long as the above-mentioned water contact angle and adhesion are satisfied.

3. Manufacturing method of sheet for work processing

The manufacturing method of the work processing sheet according to this embodiment is not particularly limited, and preferably, the work processing sheet according to this embodiment is manufactured by laminating an adhesive layer on one side of the base material.

Lamination of the adhesive layer on one side of the substrate can be performed according to a known method. For example, it is preferable to transfer the adhesive layer formed on the release sheet to one side of the substrate. In this case, a coating solution containing the adhesive composition constituting the adhesive layer and, if desired, further containing a solvent or dispersion medium is prepared, and applied on the peel-treated side (hereinafter sometimes referred to as “release surface”) of the release sheet. , the coating liquid is applied by a die coater, curtain coater, spray coater, slit coater, knife coater, etc. to form a coating film, and the coating film is dried to form an adhesive layer. The properties of the coating liquid are not particularly limited as long as it can be applied, and may contain a component for forming an adhesive layer as a solute or as a dispersoid. The release sheet in this laminate may be peeled off as a process material, or may be used to protect the adhesive surface of the adhesive layer until the sheet for work processing is attached to the cut object.

When the coating solution for forming the adhesive layer contains a crosslinking agent, by changing the above drying conditions (temperature, time, etc.) or by providing a separate heat treatment, the active energy ray-curable polymer (A) in the coating film Alternatively, the crosslinking reaction between the active energy ray non-curable polymer and the crosslinking agent may proceed to form a crosslinked structure with a desired density in the adhesive layer. In order to sufficiently advance this crosslinking reaction, after laminating an adhesive layer on a base material by the method described above, etc., the obtained sheet for work processing is cured by leaving it in an environment of, for example, 23°C and 50% relative humidity for several days. You may do it.

Instead of transferring the adhesive layer formed on the release sheet as described above to one side of the substrate, the adhesive layer may be formed directly on the substrate. In this case, the coating liquid for forming the adhesive layer described above is applied to one side of the substrate to form a coating film, and the coating film is dried to form the adhesive layer.

4. How to use the sheet for work processing

The sheet for work processing according to this embodiment can be used for processing a work (object to be cut). That is, after attaching the adhesive surface of the sheet for work processing according to the present embodiment to the object to be cut, processing of the object to be cut can be performed on the sheet for processing the work. According to the above processing, the sheet for work processing according to this embodiment can be used as a back grind sheet, dicing sheet, expand sheet, pickup sheet, etc. Here, examples of objects to be cut include semiconductor members such as semiconductor wafers and semiconductor packages, and glass members such as glass plates.

Additionally, when the sheet for work processing according to this embodiment is provided with the adhesive layer described above, the sheet for work processing can be used as a dicing/die bonding sheet. Additionally, when the workpiece processing sheet according to the present embodiment is provided with the protective film forming layer described above, the workpiece processing sheet can be used as a protective film forming and dicing sheet.

In the work processing sheet according to the present embodiment, even when the adhesive derived from the adhesive layer adheres to the cutting object, it is easy to remove the adhesive with flowing water, and the interface between the work processing sheet and the cutting object is , water caused by the flowing water is suppressed from entering the interface between the workpiece processing sheet and the obtained chip. For this reason, the workpiece processing sheet according to the present embodiment is suitable for use in processing using flowing water, and is particularly suitable for use in dicing, which involves supplying flowing water to the cut portion. In other words, the sheet for work processing according to this embodiment is suitable for use as a dicing sheet.

When using the workpiece processing sheet according to the present embodiment as a dicing sheet, general conditions can be used as the dicing conditions and flowing water supply conditions. In particular, regarding the supply conditions of flowing water, it is preferable to use pure water or the like as the water used. The supply amount of water is preferably 0.5 L/min or more, and especially 1 L/min or more. Additionally, the supply amount of water is preferably 2.5 L/min or less, and especially 2 L/min or less. Additionally, the temperature of the water is not particularly limited, and is preferably around room temperature, for example.

[Manufacturing method of processed work]

The manufacturing method of the processed work according to one embodiment of the present invention includes a bonding process of bonding the work to the surface opposite to the base in the adhesive layer of the work processing sheet described above, processing the work on the work processing sheet, A processing step of obtaining a processed work laminated on a work processing sheet, an irradiation step of irradiating an adhesive layer with active energy rays to harden the adhesive layer and lowering the adhesive force of the work processing sheet to the processed work, and activating the work processing sheet. A separation process is provided to separate the processed work from the work processing sheet after energy ray irradiation.

The work processing sheet used in the manufacturing method of the machined work of this embodiment suppresses the intrusion of water at the interface between the work processing sheet and the work or the work after processing, and allows the adhesive attached to the work to flow during processing of the work. It can be easily removed with water. For this reason, according to the manufacturing method of the machined work of this embodiment, it is possible to efficiently manufacture the machined work.

Hereinafter, each process in the manufacturing method of the processed work of this embodiment will be described.

(1) Bonding process

The bonding of the work and the sheet for work processing in the bonding process can be performed according to a conventionally known method. Additionally, when dicing the workpiece in the subsequent processing process, it is preferable to bond the ring frame to the area on the outer peripheral side of the area where the workpieces are bonded on the surface on the adhesive layer side of the workpiece processing sheet. Additionally, the workpiece to be used may be any desired material depending on the processed workpiece to be manufactured, and as a specific example, the workpiece described above can be used.

(2) Machining process

In the machining process, desired machining can be performed on the work, for example, back grinding, dicing, etc. can be performed. This processing can be performed according to conventionally known methods.

Additionally, when blade dicing using a rotating blade is performed as the above processing, a portion of the adhesive layer on the sheet for processing the work is generally cut along with the work. At this time, the adhesive constituting the adhesive layer may be rolled up by the blade and adhere to the processed work. However, in the sheet for work processing used in the method for manufacturing the processed work of this embodiment, the attached adhesive can be well removed with flowing water, as described above. From this point of view, dicing is suitable for processing in this embodiment, and blade dicing using a rotating blade is particularly suitable.

(3) Investigation process

In the irradiation process, the conditions for irradiation of active energy rays are not limited as long as the adhesion of the workpiece processing sheet to the processed workpiece can be reduced to a desired level, and the irradiation can be performed based on a conventionally known method. Types of active energy rays used include, for example, ionizing radiation, i.e.,

(4) Separation process

In the separation process, separation is performed according to the type of processing or a method depending on the obtained processed work. For example, when dicing is performed as processing and chips obtained by dividing the work into pieces are obtained by the dicing, the obtained chips are individually picked up from the sheet for work processing using a conventionally known pickup device. In addition, in order to facilitate the above-mentioned pickup, the sheet for work processing may be expanded to separate the processed works from each other.

(5) Others

In the manufacturing method of the machined work of this embodiment, processes other than the above-mentioned processes may be installed. For example, after the bonding process, a conveyance process for transporting the obtained laminate of the work and work processing sheet to a predetermined position, a storage process for storing the laminate for a predetermined period, etc. may be provided. Additionally, after the separation process, a mounting process or the like may be provided to mount the obtained machined workpiece on a predetermined base or the like.

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

For example, another layer may be provided between the base material and the adhesive layer, or on the surface of the base material opposite to the adhesive layer.

Example

Hereinafter, the present invention will be described in more detail through examples, etc., but the scope of the present invention is not limited to these examples.

[Example 1]

(1) Preparation of adhesive composition

An acrylic copolymer obtained by copolymerizing 20 parts by mass of methyl acrylate, 60 parts by mass of 2-methoxyethyl acrylate, and 20 parts by mass of 2-hydroxyethyl acrylate, and 21.4 g (2-hydroxyethyl acrylate) based on 100 g of the acrylic copolymer. methacryloyloxyethyl isocyanate (MOI) (equivalent to 80 mol% relative to the number of moles) was reacted to obtain an active energy ray-curable polymer. The weight average molecular weight (Mw) of this active energy ray-curable polymer was measured by the method described later, and was found to be 600,000.

100 parts by mass of the obtained active energy ray-curable polymer (converted to solid content, the same below), 3 parts by mass of 1-hydroxycyclohexylphenyl ketone (manufactured by BASF, product name "IRGACURE 184") as a photopolymerization initiator, and toluene diisocyanate (product name: "IRGACURE 184", manufactured by BASF) as a crosslinking agent. 10.87 parts by mass of TOSOH CORPORATION product name "Coronate L") was mixed in a solvent to obtain an adhesive composition.

(2) Formation of adhesive layer

The pressure-sensitive adhesive composition was applied to the release surface of a release sheet (manufactured by LINTEC Corporation, product name “SP-PET381031”) in which a silicone-based release agent layer was formed on one side of a polyethylene terephthalate film with a thickness of 38 μm, and dried by heating. After doing so, it was cured for 7 days under conditions of 23°C and 50%RH to form an adhesive layer with a thickness of 5 μm on the release sheet.

(3) Production of sheets for work processing

A sheet for work processing was obtained by bonding one side of an ethylene-methacrylic acid copolymer (EMAA) film with a thickness of 80 μm as a substrate to the side opposite to the release sheet of the adhesive layer formed in the above step (2).

Here, the above-mentioned weight average molecular weight (Mw) is the weight average molecular weight measured using gel permeation chromatography (GPC) (GPC measurement) and converted to standard polystyrene.

[Examples 2 to 6 and Comparative Examples 1 to 4]

A sheet for work processing was manufactured in the same manner as in Example 1, except that the composition of the acrylic copolymer was changed as shown in Table 1 and the content of the crosslinking agent was changed as shown in Table 2.

[Test Example 1] (Measurement of water contact angle)

The release sheet was peeled from the sheet for work processing manufactured in the examples and comparative examples, and the water contact angle (°) on the exposed surface of the exposed adhesive layer was measured using a fully automatic contact angle measuring device (manufactured by Kyowa Interface Science Co., Ltd., product name). “DM-701”) was used to measure under the following conditions. The results are shown in Table 3.

· Droplet volume of purified water: 2μl

· Measurement time: 3 seconds after dropping

·Image analysis method: θ/2 method

[Test Example 2] (Measurement of adhesive force)

The release sheet was peeled from the sheet for work processing manufactured in Examples and Comparative Examples, the exposed surface of the adhesive layer was laminated on the mirror surface of a mirror-finished 6-inch silicon wafer, and a load was applied by reciprocating a 2 kg roller once. It was glued together and left for 20 minutes. After that, the sheet for work processing was peeled from the silicon wafer at a peeling speed of 300 mm/min and a peeling angle of 180°, and the adhesive force to the silicon wafer F1 (mN/25 mm) was measured according to the 180° peeling method in accordance with JIS Z0237:2009. ) was measured. The results are shown in Table 3.

Additionally, the release sheet was peeled from the sheet for work processing manufactured in the examples and comparative examples, and the exposed surface of the adhesive layer was immersed in distilled water at 23°C for 12 hours and then dried at 23°C for 24 hours. Thereafter, the exposed surface was laminated on the mirror surface of a mirror-finished 6-inch silicon wafer, bonded by applying a load by reciprocating a 2 kg roller once, and left for 20 minutes. Subsequently, the sheet for work processing was peeled from the silicon wafer at a peeling speed of 300 mm/min and a peeling angle of 180°, and the adhesion to the silicon wafer was F2 after the immersion and drying according to the 180° peeling method in accordance with JIS Z0237:2009. (mN/25 mm) was measured. The results are shown in Table 3.

Also, using the values of adhesive force F1 (mN/25 mm) and adhesive force F2 (mN/25 mm) obtained as described above, the following formula (1)

Decrease rate of adhesion (%) = {(F1-F2)/F1} × 100... (One)

The reduction rate (%) of adhesive force was calculated from . The results are shown in Table 3.

[Test Example 3] (Evaluation of removability of adhesive)

The adhesive composition prepared in the Examples and Comparative Examples was applied to the release surface of a release sheet (manufactured by LINTEC Corporation, product name “SP-PET381031”) in which a silicone-based release agent layer was formed on one side of a polyethylene terephthalate film with a thickness of 38 μm. , and dried by heating to form an adhesive layer with a thickness of 5 μm on the release sheet. From the laminate of the adhesive layer and release sheet obtained in this way, 20 small pieces of the laminate with a size of 5 mm x 5 mm were cut.

Subsequently, the surface on the adhesive layer side of the 20 small pieces obtained as described above was adhered to the polished surface of a 6-inch silicon wafer (thickness: 150 μm) polished to #2000, and then a release sheet was separated from the adhesive layer. peeled off During the above sticking, the small pieces were attached with a gap of 1 mm or more between them.

Afterwards, the release sheet was peeled from the sheet for work processing manufactured in the examples and comparative examples, and a tape mounter (manufactured by LINTEC Corporation, product name “Adwill RAD2500m/12”) was placed on the exposed surface of the exposed adhesive layer. Using this method, the side opposite to the side on which the small pieces of the above-described 6-inch silicon wafer were attached was attached. Subsequently, using a dicing device (manufactured by DISCO Corporation, product name "DFD-6361"), an operation similar to dicing was performed on the 6-inch silicon wafer side while supplying flowing water to the cutting section under the following operating conditions. .

＜Operating conditions＞

· Dicing device: DFD-6361 manufactured by DISCO Corporation

Blade: NBC-2H 2050 27HECC made by DISCO Corporation

·Blade width: 0.025 ~ 0.030mm

·Knife tip protrusion: 0.640 ~ 0.760mm

·Blade rotation speed: 50000rpm

·Cutting speed　　　：20mm/sec

·Blade height: 5mm

· Flowing water supply: 1.0L/min

·Flowing water temperature　　　：room temperature

·Cutting size: 10mm×10mm

Additionally, the above “blade height: 5 mm” means that the distance between the blade and the 6-inch silicon wafer is 5 mm, and as is clear from this, in the above operation, cutting of the 6-inch silicon wafer by the blade is not performed. It doesn't work.

After completion of dicing, the presence or absence of adhesive derived from the above-mentioned small pieces remaining on the silicon wafer was confirmed, and the removability of the adhesive was evaluated based on the following criteria. The results are shown in Table 3.

○: No adhesive remained.

×: At least some adhesive remained.

[Test Example 4] (Evaluation of water intrusion)

The release sheet was peeled from the sheet for work processing manufactured in the examples and comparative examples, and the exposed surface of the exposed adhesive layer was polished to #2000 using a tape mounter (manufactured by LINTEC Corporation, product name “Adwill RAD2500m/12”). The polished surface of a 6-inch silicon wafer (thickness: 150 μm) was attached. Subsequently, using a dicing device (manufactured by DISCO Corporation, product name "DFD-6361"), dicing was performed to cut the 6-inch silicon wafer side while supplying flowing water to the cutting section under the following dicing conditions.

＜Dicing conditions＞

· Dicing device: DFD-6361 manufactured by DISCO Corporation

Blade: NBC-2H 2050 27HECC made by DISCO Corporation

·Blade width: 0.025 ~ 0.030mm

·Knife tip protrusion: 0.640 ~ 0.760mm

·Blade rotation speed: 50000rpm

·Cutting speed　　　：20mm/sec

·Notch depth: 15μm from the adhesive layer side of the workpiece processing sheet.

· Flowing water supply: 1.0L/min

·Flowing water temperature　　　：room temperature

·Cutting size: 10mm×10mm

After completion of dicing, all the obtained chips were removed from the work processing sheet, and the surface of the work processing sheet on the adhesive layer side was observed using a digital microscope (manufactured by KEYENCE, product name "VHX-1000", magnification: 500x). Based on the following criteria, water intrusion at the interface between the chip and the sheet for work processing was evaluated. The results are shown in Table 3.

○: There was no trace of water intrusion on the surface of the sheet for work processing on the adhesive layer side.

×: Traces of water intrusion were present on the surface of the sheet for work processing on the adhesive layer side.

In addition, details such as abbreviations listed in Table 1 are as follows.

BA: Butyl acrylate

MMA: Methyl methacrylate

DMAA: Dimethylacrylamide

ACMO: Acryloyl morpholine

MA: Methyl acrylate

2MEA: 2-methoxyethyl acrylic acid

MTG: Acrylic acid methoxyethylene glycol

HEA: 2-hydroxyethyl acrylic acid

MOI: Methacryloyloxyethyl isocyanate

As can be seen from Table 3, the sheet for work processing obtained in the Examples was able to have the adhesive removed satisfactorily by running water, and at the same time was able to suppress the intrusion of water.

The sheet for work processing of the present invention can be suitably used for dicing.

Claims (6)

A sheet for work processing comprising a base material and an adhesive layer laminated on one side of the base material,
The adhesive layer is composed of an active energy ray-curable adhesive,
The water contact angle of the adhesive layer on the side opposite to the substrate is 50° or more and 80° or less,
The adhesion of the work processing sheet to the silicon wafer is set to F1, and the work processing sheet is immersed in distilled water at 23° C. for 12 hours and dried at 23° C. for 24 hours. Then, the adhesion of the work processing sheet to the silicon wafer is In the case of F2, the following equation (1)
Decrease rate of adhesion (%) = {(F1-F2)/F1} × 100... (One)
A sheet for work processing, characterized in that the reduction rate of adhesive force calculated from is 20% or more and 50% or less. According to paragraph 1,
A sheet for work processing, characterized in that the adhesive force F1 is 1000 mN/25 mm or more and 10000 mN/25 mm or less. According to paragraph 1,
A sheet for work processing, characterized in that the adhesive force F2 is 900 mN/25 mm or more and 8000 mN/25 mm or less. According to paragraph 1,
The active energy ray-curable adhesive is at least one selected from methyl acrylate, 2-methoxyethyl (meth)acrylate, ethyl carbitol (meth)acrylate, and methoxyethylene glycol (meth)acrylate as a monomer unit constituting the polymer. A sheet for work processing, characterized in that it is an adhesive formed from an adhesive composition containing an acrylic copolymer containing. According to paragraph 1,
A sheet for work processing, characterized as being a dicing sheet. A bonding process of bonding a workpiece to a side of the adhesive layer of the workpiece processing sheet according to any one of claims 1 to 5 on a side opposite to the base material,
A machining process of machining the work on the work machining sheet to obtain a machined work laminated on the work machining sheet,
An irradiation step of irradiating active energy rays to the adhesive layer to harden the adhesive layer and reduce the adhesive force of the workpiece processing sheet to the processed workpiece, and
A separation process of separating the processed work from the work sheet after irradiation with active energy rays,
A method of manufacturing a processed work, comprising: