KR102515877B1 - Sheet for work processing and manufacturing method of processed work - Google Patents

Abstract

A sheet for work processing comprising a base material and an adhesive layer laminated on one side of the base material, wherein the pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive, and the pressure-sensitive adhesive layer is formed on a surface opposite to the base material. The oxygen atom ratio R ₀ measured by X-ray photoelectron spectroscopy is 28 atomic% or less, and among positions in the pressure-sensitive adhesive layer, X-ray photoelectrons are located at a depth of 100 nm from the surface opposite to the base material in the pressure-sensitive adhesive layer. A workpiece processing sheet characterized in that the oxygen atom ratio R ₁₀₀ measured by spectroscopic analysis is 20 atomic% or more and 29 atomic% or less. In such a workpiece processing sheet, the pressure-sensitive adhesive derived from the pressure-sensitive adhesive layer adhered to the processed workpiece can be satisfactorily removed with running water, and the processed workpiece can be satisfactorily separated.

Description

Sheet for work processing and manufacturing method of processed work

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

Semiconductor wafers such as silicon and gallium arsenide and various packages (hereinafter, collectively referred to as "objects to be cut") are manufactured in a large-diameter state, and these are element pieces. (Hereinafter, it may be described as “chip”.) After being separated (diced) and individually separated (picked up), it is moved to the next step, the mounting step. At this time, the object to be cut, such as a semiconductor wafer, is provided to each step of dicing, washing, drying, expanding, picking up, and mounting in a state of being adhered to a sheet for work processing including a base material and an adhesive layer do.

In the dicing process described above, the dicing blade, the object to be cut, and the sheet for processing the workpiece are heated by frictional heat generated between the rotating dicing blade and the sheet for processing the workpiece or the object to be cut. Also, in the dicing process, there are cases in which cutting fragments are generated from the object to be cut or the workpiece processing sheet and adhere to the chips.

For this reason, when performing a dicing process, it is normally performed to cool the dicing blade etc. by supplying flowing water to the cutting part, and to remove the generated cutting fragments from the chips.

In Patent Literature 1, for the purpose of promoting the removal of cutting chips by such running water, the contact angle of the surface opposite to the base material in the pressure-sensitive adhesive layer before ultraviolet irradiation with pure water is 82 ° to 114 °, and further, methylene iodide A workpiece processing sheet having a contact angle of 44° to 64° and a peak value of a probe tack test of 294 to 578 kPa in an adhesive layer before irradiation with ultraviolet rays is disclosed.

Patent Document 1: Japanese Patent No. 5019657

However, when the dicing process is performed using the conventional workpiece processing sheet disclosed in Patent Literature 1, the adhesive derived from the adhesive layer of the workpiece processing sheet cannot be sufficiently removed from the processed workpiece.

Further, in general, when separating chips from the sheet for work processing in the pick-up process, it is required that chips can be separated without excessive force, thereby preventing defects such as chip breakage.

The present invention has been made in view of such an actual situation, and is for processing workpieces in which the adhesive derived from the adhesive layer adhering to the workpiece after processing can be satisfactorily removed with running water and the workpiece after processing can be separated satisfactorily. It is an object of the present invention to provide a sheet and a method for manufacturing a processed work using the sheet for processing the work.

In order to achieve the above object, the first invention of the present invention is a sheet for work processing comprising a base material and an adhesive layer laminated on one side of the base material, wherein the pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive, In the pressure-sensitive adhesive layer, the oxygen atom ratio R ₀ measured by X-ray photoelectron spectroscopy on the side opposite to the base material is 28 atomic% or less, and in a position in the pressure-sensitive adhesive layer, on the side opposite to the base material in the pressure-sensitive adhesive layer. A sheet for work processing characterized in that the oxygen atom ratio R ₁₀₀ measured by X-ray photoelectron spectroscopy at a depth of 100 nm from the surface of is 20 atomic% or more and 29 atomic% or less (Invention 1).

In the sheet for workpiece processing according to the above invention (Invention 1), the oxygen atom ratio measured by X-ray photoelectron spectroscopy and molecular analysis on the surface of the pressure-sensitive adhesive layer on the side opposite to the base material (hereinafter sometimes referred to as "adhesive surface") When R ₀ is 28 atom% or less, the adhesive surface has excessive hydrophobicity, and the workpiece after processing is easily separated. In addition, the oxygen atom ratio R ₁₀₀ measured by X-ray photoelectron spectroscopy at a position in the pressure-sensitive adhesive layer at a depth of 100 nm from the adhesive surface is 20 atom% or more and 29 atom% or less, and the pressure-sensitive adhesive adhered to the workpiece after processing, that The surface has appropriate hydrophilicity, and the adhesive adhering to the work after processing can be satisfactorily removed with running water.

In the above invention (Invention 1), the value of the oxygen atom ratio R ₀ is greater than the value of the oxygen atom ratio R ₁₀₀ , and the following formula (1)

Oxygen atom ratio reduction rate (%) = {(Oxygen atom ratio R ₀ -Oxygen atom ratio R ₁₀₀ )/Oxygen atom ratio R ₀ ｝×100 . (One)

It is preferable that the reduction rate of the oxygen atom ratio calculated from is 0% or more and 15% or less (Invention 2).

In the above inventions (inventions 1 and 2), it is preferable that the active energy ray-curable pressure-sensitive adhesive is a pressure-sensitive adhesive formed from a pressure-sensitive adhesive composition containing an active energy ray-polymerizable branched polymer (invention 3).

In the above invention (Inventions 1 to 3), the pressure-sensitive adhesive composition contains an active energy ray-curable polymer obtained by reacting an acrylic copolymer having a functional group-containing monomer unit with an unsaturated group-containing compound having a functional group bonded to the functional group. , The acrylic copolymer contains 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. It is preferable to include (Invention 4).

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

In the second aspect of the present invention, a bonding step of bonding a workpiece to a surface of the pressure-sensitive adhesive layer of the workpiece processing sheet (Invention 1 to 5) on the opposite side to the base material, and the workpiece on the workpiece processing sheet A processing step of obtaining a processed workpiece laminated on the workpiece processing sheet by irradiating the pressure-sensitive adhesive layer with active energy rays to cure the pressure-sensitive adhesive layer, and adhesive strength of the workpiece processing sheet to the processed workpiece and a separation step of separating the processed workpiece from the workpiece processing sheet after irradiation with active energy rays (Invention 6).

The sheet for processing a workpiece according to the present invention can satisfactorily remove the adhesive derived from the adhesive layer adhering to the workpiece after processing with running water, and can satisfactorily separate the workpiece after processing. Further, according to the method for manufacturing a processed workpiece according to the present invention, it is possible to efficiently manufacture a processed workpiece.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is 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 workpiece processing

In the sheet for work processing according to the present embodiment, the oxygen atom ratio R ₀ measured by X-ray photoelectron spectroscopy on the surface (adhesive surface) of the pressure-sensitive adhesive layer on the side opposite to the substrate is 28 atomic% or less. When the oxygen atom ratio R ₀ is 28 atom% or less, the adhesive surface has appropriate hydrophobicity, and excessive increase in the adhesive force of the workpiece processing sheet to the workpiece after processing is suppressed. This makes it possible to favorably separate the work after processing from the sheet for processing the work. In particular, when a silicon wafer is used as a workpiece, a relatively large number of hydrophilic groups are present on the surface of the silicon wafer, and an adhesive surface having appropriate hydrophobicity comes into contact with this surface, making it easy to separate the workpiece after processing. In addition, the details of the measuring method of the above-mentioned oxygen atom ratio R ₀ are as describing in the test example mentioned later.

When the oxygen atom ratio R ₀ described above exceeds 28 atom%, the adhesive surface has relatively high hydrophilicity, and the adhesive force of the workpiece processing sheet to the workpiece after processing is excessively high. In this case, excessive force is required when removing the processed workpiece from the workpiece processing sheet, and there is a possibility that a defect such as breakage of the processed workpiece may occur. From the viewpoint of avoiding such a problem, the oxygen atom ratio R ₀ is preferably 27 atomic% or less.

Further, the oxygen atom ratio R ₀ is preferably 20 atomic % or more, particularly preferably 22 atomic % or more. When the oxygen atom ratio R ₀ is 20 atom% or more, the hydrophilicity on the adhesive surface becomes appropriate, and the workpiece processing sheet easily exhibits good adhesiveness to the workpiece. This makes it possible to effectively suppress unintentional peeling of the workpiece before or after processing, such as when processing the workpiece or conveying the workpiece or the processed workpiece in a stacked state on a sheet for processing the workpiece.

In the sheet for work processing according to the present embodiment, the oxygen atom ratio R ₁₀₀ measured by X-ray photoelectron spectroscopy at a position at a depth of 100 nm from the adhesive surface in the position in the pressure-sensitive adhesive layer is 20 atomic% or more and 29 atomic% or less. This allows the pressure-sensitive adhesive inside the pressure-sensitive adhesive layer to have appropriate hydrophilicity.

In general, in dicing using a dicing blade, the rotating dicing blade is applied to an object to be cut while supplying flowing water to the cut portion, and the object to be cut is cut. At this time, the rotating dicing blade may contact not only the object to be cut but also the pressure-sensitive adhesive layer. At the contacted portion, the pressure-sensitive adhesive layer is cut or the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is rolled up by the dicing blade, and as a result, small pieces of the pressure-sensitive adhesive are formed. The small pieces adhere to the object to be cut or formed chips, adversely affect subsequent handling of the chips, or cause deterioration in the quality of the chips or products on which the chips are mounted. Here, since the small pieces of the pressure-sensitive adhesive are formed as described above, most of the small pieces exist inside the pressure-sensitive adhesive layer when forming the pressure-sensitive adhesive layer.

In the workpiece processing sheet according to the present embodiment, as described above, since the adhesive inside the pressure-sensitive adhesive layer has appropriate hydrophilicity, small pieces of the adhesive as described above are generated during processing, and the small pieces form the workpiece after processing ( chip, etc.), the surface of the small piece has appropriate hydrophilicity. For this reason, according to the sheet for processing a workpiece according to the present embodiment, the adhesive adhering to the workpiece after processing can be satisfactorily removed by flowing water supplied during processing.

On the other hand, if the oxygen atom ratio R ₁₀₀ is less than 20 atom%, the pressure-sensitive adhesive inside the pressure-sensitive adhesive layer does not have sufficient affinity for water, and small pieces of the pressure-sensitive adhesive cannot be sufficiently removed from the workpiece after processing. From the viewpoint of avoiding such a problem, the oxygen atom ratio R ₁₀₀ described above is preferably 21 atomic% or more.

In addition, when the above-mentioned oxygen atom ratio R ₁₀₀ exceeds 29 atomic%, the pressure-sensitive adhesive inside the pressure-sensitive adhesive layer exhibits excessive affinity for water, and accordingly, the surface of the pressure-sensitive adhesive layer also has high affinity for water. . As a result, the intrusion of water cannot be suppressed, and chip flying or chip damage occurs during dicing. From the viewpoint of avoiding such a problem, it is preferable that the oxygen atom ratio R ₁₀₀ described above is 27 atomic% or less. Details of the method for measuring the oxygen atom ratio R ₁₀₀ are as described in the test examples described later.

In the sheet for work processing according to the present embodiment, the value of _the oxygen atom ratio R ₁₀₀ may be greater than the value of the oxygen atom ratio R ₀ as long as the oxygen atom ratio R 0 and the oxygen atom ratio R ₁₀₀ are within the above-mentioned ranges, respectively; Alternatively, the value of the oxygen atom ratio R ₀ may be greater than the value of the oxygen atom ratio R ₁₀₀ . Alternatively, the oxygen atom ratio R ₀ and the oxygen atom ratio R ₁₀₀ may be the same. When the value of the oxygen atom ratio R ₀ is larger than the value of the oxygen atom ratio R ₁₀₀ , the following formula (1)

Reduction rate (%) of oxygen atom ratio = {(Oxygen atom ratio R ₀ -Oxygen atom ratio R ₁₀₀ )/Oxygen atom ratio R ₀ ｝×100 . (One)

The reduction rate of the oxygen atom ratio calculated from is preferably 0% or more, particularly preferably 1% or more, and more preferably 2% or more. In addition, the reduction rate is preferably 15% or less, particularly preferably 12% or less, and more preferably 10% or less. When the rate of decrease of the oxygen atom ratio is within the above-mentioned range, it is easy to achieve both satisfactory removal of the adhesive with running water and satisfactory separation of the processed workpiece from the workpiece processing sheet.

In the workpiece processing sheet according to the present embodiment, the adhesive strength of the workpiece processing sheet to the silicon wafer is preferably 1000 mN/25 mm or more, particularly preferably 1200 mN/25 mm or more, and more preferably 1500 mN/25 mm or more. it is desirable The adhesive force herein refers to the adhesive force in a state in which no active energy ray is irradiated to the workpiece processing sheet and no curing of the pressure-sensitive adhesive layer occurs. Also, regarding the "adhesive force" described without mentioning the presence or absence of active energy ray irradiation throughout the present specification, the adhesive force in a state where the workpiece processing sheet is not irradiated with active energy rays and the pressure-sensitive adhesive layer is not cured. do it by saying Since the above-mentioned adhesive force is 1000 mN/25 mm or more, it is easy to hold the workpiece to be processed well on the workpiece processing sheet, and the workpiece during processing or after processing can be transported in a laminated state on the workpiece processing sheet. peeling of the workpiece before or after processing can be favorably suppressed. In particular, when the workpiece after processing is a chip, scattering of the chip from the sheet for processing the workpiece can be suppressed satisfactorily.

Further, the adhesive force of the workpiece processing sheet to the silicon wafer is preferably 5000 mN/25 mm or less, particularly preferably 4500 mN/25 mm or less, and more preferably 3000 mN/25 mm or less. When the adhesive force is 5000 mN/25 mm or less, it becomes easy to adjust the adhesive force within the range described later after irradiation with active energy rays. In addition, the detail of the measuring method of the adhesive force of the sheet|seat for work processing with respect to the silicon wafer is as describing in the test example mentioned later.

Further, in the workpiece processing sheet according to the present embodiment, after irradiating the workpiece processing sheet with active energy rays, it is preferable that the adhesive force of the workpiece processing sheet to the silicon wafer is 65 mN/25 mm or less. When the adhesive force is 65 mN/25 mm or less, it is easier to separate the processed workpiece from the workpiece processing sheet by irradiating the workpiece processing sheet with active energy rays after the workpiece processing is completed.

2. Component members of sheet for work processing

(1) description

In the sheet for work processing according to the present embodiment, the substrate exhibits a desired function in the process of using the sheet for work processing, and preferably exhibits good permeability to active energy rays irradiated for curing the pressure-sensitive adhesive layer. As long as it is to do it, it is not specifically limited.

For example, the base material is preferably a resin film mainly composed of a resin-based material, and specific examples include an ethylene-vinyl acetate copolymer film; ethylene-based copolymer films such as ethylene-(meth)acrylic acid copolymer films, ethylene-(meth)acrylate copolymer films, and other ethylene-(meth)acrylic acid ester copolymer films; Polyolefin films, such as a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, an ethylene-norbornene copolymer film, and a norbornene resin film; polyvinyl chloride-based films such as polyvinyl chloride films and vinyl chloride copolymer films; Polyester-based films, such as a polyethylene terephthalate film, a polybutylene terephthalate film, and a polyethylene naphthalate; (meth)acrylic acid ester copolymer film; polyurethane film; polyimide film; polystyrene film; polycarbonate film; A fluororesin film etc. are mentioned. Examples of the polyethylene film include a low density polyethylene (LDPE) film, a linear low density polyethylene (LLDPE) film, and a high density polyethylene (HDPE) film. In addition, these crosslinked films and denatured films called ionomer films are also used. In addition, the base material may be a laminated film formed by laminating a plurality of the above-mentioned films. In this laminated film, the materials constituting each layer may be of the same type or of different types. As the 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 applies to other similar terms.

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

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

The thickness of the substrate can be appropriately set according to 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. Moreover, it is preferable that the said thickness is normally 450 micrometers or less, and it is especially preferable that it is 300 micrometers or less.

(2) adhesive layer

In the sheet for work processing according to the present embodiment, the pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive and can exhibit desired adhesive strength, and the above-mentioned oxygen atom ratio R ₀ and oxygen atom ratio R ₁₀₀ are within the above-mentioned ranges, respectively. It is not particularly limited as long as it becomes

In the workpiece processing sheet according to the present embodiment, the pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive, and when separating the pressure-sensitive adhesive surface from the workpiece after processing adhered to the pressure-sensitive adhesive layer, active energy ray irradiation Thus, the pressure-sensitive adhesive layer can be cured, and the adhesive force of the sheet for processing the workpiece to the workpiece after processing can be reduced. This facilitates separation of the adhesive surface of the pressure-sensitive adhesive layer and the workpiece after processing.

The pressure-sensitive adhesive layer in the present embodiment may be formed of a pressure-sensitive adhesive composition containing a polymer having active energy ray curability, and may include an active energy ray non-curable polymer (a polymer having no active energy ray curable property) and at least one active energy. It may be formed from a pressure-sensitive adhesive composition containing a monomer and/or an oligomer having a linearly curable group.

First, the case where the pressure-sensitive adhesive layer in the present embodiment is formed of a pressure-sensitive adhesive composition containing a polymer having active energy ray curability will be described below.

The active energy ray-curable polymer is a (meth)acrylic acid ester (co)polymer (A) in which a functional group (active energy ray-curable group) is introduced into the side chain (hereinafter referred to as "active energy ray-curable polymer (A)). )”.) is preferable. The 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, as a monomer unit constituting the polymer, a monomer for adjusting the hydrophilicity of the acrylic copolymer (a1) (hereinafter sometimes referred to as a “hydrophilic property adjusting monomer”). In particular, as specific examples thereof, methyl acrylate, (meth)acrylate 2-methoxyethyl, (meth)acrylate ethyl carbitol ((meth)acrylate ethoxyethoxyethyl) and (meth)acrylate methoxyethylene glycol are selected from It is preferable to include at least 1 type.

In the pressure-sensitive adhesive sheet according to the present embodiment, when the acrylic copolymer (a1) uses the hydrophilic property adjusting monomer described above, it is easy to adjust the oxygen atom ratio R ₁₀₀ within the above range. For this reason, many of the above-mentioned hydrophilicity adjusting monomers have relatively many oxygen atoms, and by using the acrylic copolymer (a1) composed of the above monomers, the absolute amount of oxygen atoms in the pressure-sensitive adhesive layer also increases, thereby It is considered that this is because it becomes easy to adjust the oxygen atom ratio R ₁₀₀ within the above range. However, it is not limited to the above reasons.

In addition, from the viewpoint of being easy to adjust the above-mentioned oxygen atom ratio R ₁₀₀ to the above-mentioned range, the acrylic copolymer (a1) contains methyl acrylate and 2-methoxyethyl acrylate among the above-mentioned monomers as monomer units constituting the polymer. And it is preferable that at least 1 sort(s) of acrylic acid methoxyethylene glycol is included.

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, particularly preferably 20% by mass or more, and more preferably 30% by mass or more. desirable. Moreover, it is preferable that content of methyl acrylate is 85 mass % or less. With such a content, it becomes easier to adjust the above-mentioned oxygen atom ratio R ₁₀₀ in the formed pressure-sensitive adhesive layer to the above-mentioned range. In addition, in this specification, the content (mass %) of methyl acrylate mentioned above means content with respect to all the monomers which comprise acrylic copolymer (a1). In addition, also about content (mass %) of other monomers mentioned later, content with respect to all the monomers which comprise an acryl-type copolymer (a1) shall be meant.

Further, 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, particularly 20% by mass or more. It is preferable, and it is more preferable that it is 30 mass % or more. Further, the content of 2-methoxyethyl acrylate is preferably 85% by mass or less, particularly preferably 80% by mass or less, and more preferably 70% by mass or less. With such a content, it becomes easier to adjust the above-mentioned oxygen atom ratio R ₁₀₀ in the formed pressure-sensitive adhesive layer to the above-mentioned range.

In the case where 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 mass % or more, and it is especially preferable that it is 30 mass % or more, and it is more preferable that it is 50 mass % or more. Moreover, it is preferable that the said total value is 90 mass % or less, and it is especially preferable that it is 85 mass % or less. With the above total value being in this range, it becomes easier to adjust the above-mentioned oxygen atom ratio R ₁₀₀ in the above-mentioned range in the formed pressure-sensitive adhesive layer.

Further, 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, particularly preferably 30% by mass or more. . Moreover, it is preferable that content of methoxyethylene glycol acrylate is 90 mass % or less, and it is especially preferable that it is 85 mass % or less. With such a content, it becomes easier to adjust the above-mentioned oxygen atom ratio R ₁₀₀ in the formed pressure-sensitive adhesive layer to the above-mentioned range.

The acrylic copolymer (a1) preferably contains a structural unit derived from a functional group-containing monomer and a structural unit derived from a (meth)acrylic acid ester monomer or a derivative thereof, in addition to the hydrophilicity adjusting monomer described above.

Examples of the functional group-containing monomer as the structural unit of the acrylic copolymer (a1) include monomers having a polymerizable double bond and a functional group such as a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, and an epoxy group in the molecule. Among these, hydroxyl group-containing monomers and amino groups It is preferable to contain at least 1 sort(s) of containing monomer and a substituted amino group containing monomer.

Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate , (meth)acrylic acid 3-hydroxybutyl, (meth)acrylic acid 4-hydroxybutyl, etc. are mentioned, These are used individually or in combination of 2 or more types.

Examples of the amino group-containing monomer or substituted amino group-containing monomer include aminoethyl (meth)acrylate and n-butylaminoethyl (meth)acrylate. These may be used independently or may be used 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 may be used alone or in combination of two or more. You may use it. However, it is preferable that the acrylic copolymer (a1) does not contain a carboxyl group-containing monomer. Adjustment of the water contact angle becomes easier because the acrylic copolymer (a1) does not contain a carboxyl group-containing monomer.

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

As the (meth)acrylic acid ester monomer constituting the acrylic copolymer (a1), in addition to a (meth)acrylic acid alkyl ester having 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.

Examples of (meth)acrylic acid alkyl esters include (meth)acrylic acid alkyl esters having 1 to 18 carbon atoms in the alkyl group, such as methyl methacrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and (meth)acrylic acid. n-butyl, 2-ethylhexyl (meth)acrylate and the like are preferably used. These may be used individually by 1 type, and may be used in combination of 2 or more type.

Examples of the alicyclic structure-containing monomer include cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, adamantyl (meth)acrylate, isobornyl (meth)acrylate, and dicyclophene (meth)acrylate. tenyl, dicyclopentenyloxyethyl (meth)acrylate and the like are preferably used. These may be used individually by 1 type, and may be used in combination of 2 or more type.

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

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

The active energy ray-curable polymer (A) is obtained by reacting the 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 functional group of the unsaturated group-containing compound (a2) can be appropriately selected depending on the kind 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 to be 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 carbon-carbon double bonds polymerizable by active energy rays in one molecule. Specific examples of such an 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 a diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth)acrylate; Acryloyl monoisocyanate compound obtained by reaction of a diisocyanate compound or a 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 and the like.

The amount of the unsaturated group-containing compound (a2) is preferably 50 mol% or more, particularly preferably 60 mol% or more, and more preferably 70 mol%, based on the number of moles of the functional group-containing monomers of the acrylic copolymer (a1). % or higher is used. Further, the amount of the unsaturated group-containing compound (a2) is preferably 95 mol% or less, particularly preferably 93 mol% or less, and more preferably 93 mol% or less, relative to the number of moles 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 reaction temperature, pressure, and solvent 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, the presence or absence of a catalyst, and the 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 in the acrylic copolymer (a1) to form the active energy ray-curable polymer (A). is 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. Moreover, it is preferable that the said weight average molecular weight (Mw) is 1.5 million or less, and it is especially preferable that it is 1 million or less. In addition, the weight average molecular weight (Mw) in this specification is a standard polystyrene conversion value measured by the gel permeation chromatography method (GPC method).

In the present embodiment, even when the pressure-sensitive adhesive composition contains an active energy ray-curable polymer called an active energy ray-curable polymer (A), the pressure-sensitive adhesive composition contains an active energy ray-curable monomer and/or oligomer (B). It may contain more.

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

Examples of such active energy ray-curable monomers and/or oligomers (B) include monofunctional acrylic acid esters such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate; )Acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol Polyfunctional acrylic acid esters such as di(meth)acrylate, polyethylene glycol di(meth)acrylate, dimethyloltricyclodecane di(meth)acrylate, polyester oligo(meth)acrylate, polyurethane oligo(meth)acrylate Acrylates etc. are mentioned.

When blending the active energy ray-curable monomer and/or oligomer (B) together with the active energy ray-curable polymer (A), the content of the active energy ray-curable monomer and/or oligomer (B) in the pressure-sensitive adhesive composition is It is preferably more than 0 parts by mass, and particularly preferably 60 parts by mass or more with respect to 100 parts by mass of the active energy ray-curable polymer (A). The content is preferably 250 parts by mass or less, particularly preferably 200 parts by mass or less, based on 100 parts by mass of the active energy ray-curable polymer (A).

Here, when using an ultraviolet ray as the active energy ray for curing the active energy ray-curable pressure-sensitive adhesive, it is preferable that the pressure-sensitive adhesive composition in the present embodiment contains a photopolymerization initiator (C). By using this photopolymerization initiator (C), the polymerization curing time and the amount of light irradiation can be reduced.

As the photopolymerization initiator (C), specifically, 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, 1-hydroxycyclohexylphenyl ketone, benzyldiphenylsulfide, tetramethylthiurammonosulfide, azobisisobutyronitrile, benzyl, dibenzyl, di Acetyl, β-chloroanthraquinone, (2,4,6-trimethylbenzyl diphenyl) phosphine oxide, 2-benzothiazole-N,N-diethyldithiocarbamate, oligo{2-hydroxy -2-methyl-1-[4-(1-propenyl)phenyl]propanone}, 2,2-dimethoxy-1,2-diphenylethane-1-one, etc. are mentioned. These may be used independently and may use 2 or more types together.

The content of the photopolymerization initiator (C) in the pressure-sensitive adhesive composition is determined by the active energy ray-curable polymer (A) (when blending the active energy ray-curable monomer and/or oligomer (B), the active energy ray-curable polymer (A) and It is preferably 0.1 part by mass or more, particularly preferably 0.5 part by mass or more, with respect to 100 parts by mass) of the total amount of the active energy ray-curable monomer and/or oligomer (B). In addition, the above content is the active energy ray-curable polymer (A) (when blending the active energy ray-curable monomer and/or oligomer (B), the active energy ray-curable polymer (A) and the active energy ray-curable monomer and It is preferably 10 parts by mass or less, particularly preferably 6 parts by mass or less with respect to 100 parts by mass of the total amount of / or oligomer (B) 100 parts by mass.

It is preferable that the adhesive composition in this embodiment contains the additive (D) for adjusting the oxygen atom ratio in an adhesive layer. Examples of such additives include active energy ray polymerizable branched polymers, branched polymers, epoxy resins, and the like. Preference is given to using polymerizable branched polymers.

The active energy ray polymerizable branched polymer is a type of active energy ray polymerizable compound, and means a polymer having an active energy ray polymerizable group and a branched structure. The pressure-sensitive adhesive layer in the present embodiment is formed of a pressure-sensitive adhesive composition containing an active energy ray polymerizable branched polymer, and the oxygen atom ratio R ₀ measured by X-ray photoelectron spectroscopy on the pressure-sensitive adhesive surface is adjusted to 28 atomic% or less. it becomes easier to do The reasons for this include, but are not limited to, the following. When forming a pressure-sensitive adhesive layer using an adhesive composition containing an active energy ray-polymerizable branched polymer, the active energy ray-polymerizable branched polymer tends to be unevenly distributed on the surface side in the pressure-sensitive adhesive layer. For this reason, in the formed pressure-sensitive adhesive layer, the content of the active energy ray polymerizable branched polymer is more present as it is closer to the surface compared to the inside. Here, since the active energy ray polymerizable branched polymer itself is a component with a relatively small oxygen atom ratio, it is easy to achieve an oxygen atom ratio of 28 atomic% or less on the adhesive surface where the active energy ray polymerizable branched polymer is present in a larger amount. lose

In addition, since the active energy ray polymerizable branched polymer has an active energy ray polymerizable group, when the sheet for work processing is irradiated with active energy rays, active energy ray polymerizable branched polymers or active energy ray polymerizable branched polymers are active. A polymerization reaction can occur between components having an energy ray-curable group, whereby the migration of the active energy ray-polymerizable branched polymer to the workpiece after processing is suppressed, and the pressure-sensitive adhesive layer after active energy ray irradiation is further cured. , it becomes easy to effectively separate the workpiece after processing from the sheet for workpiece processing.

As described above, the active energy ray polymerizable branched polymer has a specific structure (e.g., degree of branched structure, active energy ray polymerizable property in one molecule) as long as it is a polymer having an active energy ray polymerizable group and a branched structure. The number of groups) is not particularly limited. As a method for obtaining such an active energy ray-polymerizable branched polymer, for example, a monomer having two or more radically polymerizable double bonds in a molecule, a monomer having an active hydrogen group and one radically polymerizable double bond in a molecule, and 1 A polymer having a branched structure obtained by polymerizing a monomer having two radically polymerizable double bonds in a molecule is reacted with a compound having a functional group capable of forming a bond by reacting with an active hydrogen group and at least one radically polymerizable double bond in a molecule. can be obtained by doing Each of the three types of monomers described above may be (meth)acrylic acid ester or (meth)acrylic acid, and in this case, the active energy ray polymerizable branched polymer is an acrylic polymer.

The weight average molecular weight of the active energy ray polymerizable branched polymer is preferably 1000 or more, particularly preferably 3000 or more. Moreover, it is preferable that it is 100000 or less, and, as for the said weight average molecular weight, it is especially preferable that it is 30000 or less. When the weight average molecular weight is within the above-mentioned range, it becomes easy to adjust the oxygen atom ratio R ₀ measured by X-ray photoelectron spectroscopy on the adhesive surface to 28 atomic% or less.

The content of the additive (D) in the pressure-sensitive adhesive composition is 100 parts by mass of the active energy ray-curable polymer (A) (when blending the active energy ray-curable monomer and/or oligomer (B), the active energy ray-curable polymer (A) ) and active energy ray-curable monomer and/or oligomer (B), relative to 100 parts by mass), preferably 0.05 part by mass or more, particularly preferably 0.1 part by mass or more. In addition, the above content is 100 parts by mass of the active energy ray-curable polymer (A) (when blending the 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 1 part by mass or less, particularly preferably 0.5 part by mass or less, relative to 100 parts by mass of the total amount of monomers and/or oligomers (B) of . When the content of the additive (D) is within the above-mentioned range, it becomes easy to adjust the oxygen atom ratio in the pressure-sensitive adhesive layer to a desired range.

The adhesive composition in this embodiment may mix|blend other components suitably other than the component demonstrated above. Other components include, for example, an active energy ray non-curable polymer component or oligomer component (E), a crosslinking agent (F), and the like.

Examples of the active energy ray non-curable polymer component or oligomer component (E) include polyacrylic acid esters, polyesters, polyurethanes, polycarbonates, polyolefins, and the like, and have a weight average molecular weight (Mw) of 3000 ~ 2.5 million polymers or oligomers are preferred. By blending the component (E) into the active energy ray-curable pressure-sensitive adhesive, the adhesiveness and peelability before curing, the strength after curing, the adhesiveness to other layers, storage stability, and the like can be improved. The compounding amount of the component (E) is not particularly limited, and is appropriately determined within a 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 (F), a polyfunctional compound having reactivity with a 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 phenolic resins. etc. can be mentioned.

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

Next, the case where the pressure-sensitive adhesive layer in the present embodiment is formed of a pressure-sensitive adhesive composition containing an active energy ray non-curable polymer component and a monomer and/or oligomer having at least one active energy ray-curable group is described below. do.

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

As the monomer and/or oligomer having at least one or more active energy ray-curable groups, those similar to 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 curable group is based on 100 parts by mass of the active energy ray non-curable polymer component. It is preferable that it is 1 mass part or more of a monomer and/or oligomer, and it is especially preferable that it is 60 mass parts or more. In addition, the above compounding ratio is preferably 200 parts by mass or less of a monomer and/or oligomer having at least one active energy ray-curable group based on 100 parts by mass of the active energy ray-curable polymer component, and more preferably 160 parts by mass or less. .

Also in this case, the photopolymerization initiator (C), additive (D) and crosslinking agent (F) can be appropriately blended in the same manner as above.

The pressure-sensitive adhesive layer is preferably 1 μm or more, and particularly preferably 5 μm or more. Moreover, it is preferable that the said thickness is 50 micrometers or less, and it is especially preferable that it is 40 micrometers or less. When the thickness of the pressure-sensitive adhesive layer is within the above range, it is easy to achieve desired adhesive force with respect to the workpiece.

(3) release sheet

In the workpiece processing sheet according to the present embodiment, a release sheet may be laminated on the adhesive face of the pressure-sensitive adhesive layer for the purpose of protecting the face until the face is attached to the work. The configuration of the release sheet is arbitrary, and a release treatment of a plastic film with a release agent or the like is exemplified. Specific examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. As the release agent, silicone-based, fluorine-based, long-chain alkyl-based, and the like can be used, and among these, silicone-based, inexpensive and from which stable performance is obtained, is preferable. The thickness of the release sheet is not particularly limited, but is usually 20 μm or more and 250 μm or less.

(4) Other members

In the sheet for work processing according to the present embodiment, an adhesive layer may be laminated on the adhesive face of the adhesive layer. In this case, the sheet for work processing according to the present embodiment is equipped with an adhesive layer as described above, and can be used as a dicing die-bonding sheet. In such a sheet for processing a workpiece, a chip in which the separated adhesive layer is laminated can be obtained by attaching the workpiece to the surface of the adhesive layer opposite to the adhesive layer and dicing the adhesive layer together with the workpiece. The chip can be easily fixed to the object on which the chip is mounted by this segmented adhesive layer. As the material constituting the above-described 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-curing) thermosetting adhesive component.

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 pressure-sensitive adhesive layer. In this case, the sheet for work processing according to the present embodiment can be used as a sheet for forming a protective film and for dicing. In such a sheet for processing a workpiece, a chip in which the separated protective film forming layer is laminated can be obtained by attaching the workpiece to the surface opposite to the pressure-sensitive adhesive layer in the protective film forming layer and dicing the protective film forming layer together with the workpiece. As the work, it is preferable to use one having a circuit formed on one side thereof, and in this case, usually, a protective film forming layer is laminated on the side opposite to the side on which the circuit is formed. By curing the separated protective film forming layer at a predetermined timing, a protective film having sufficient durability can be formed into a chip. The protective film forming layer is preferably composed of an uncured curable adhesive.

In the workpiece processing sheet according to the embodiment of the present application, the oxygen atom ratio R ₀ and the oxygen atom ratio R ₁₀₀ are within the above-mentioned ranges, respectively. For the pressure-sensitive adhesive layer before layering, the oxygen atom ratio R ₀ and the oxygen atom ratio R ₁₀₀ may each fall within the above-mentioned ranges.

3. Manufacturing method of sheet for work processing

The method for producing the sheet for work processing according to the present embodiment is not particularly limited, and preferably, the sheet for work processing according to the present embodiment is manufactured by laminating a pressure-sensitive adhesive layer on one side of a base material.

Lamination of the pressure-sensitive adhesive layer on one side of the base material can be performed in accordance with a known method. For example, it is preferable to transfer the pressure-sensitive adhesive layer formed on the release sheet to one side of the base material. In this case, a coating solution containing the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer and, if desired, a solvent or a dispersion medium is prepared, and applied onto the release-treated surface (hereinafter sometimes referred to as "release surface") of the release sheet. , A pressure-sensitive adhesive layer can be formed by applying the coating solution with a die coater, curtain coater, spray coater, slit coater, knife coater or the like to form a coating film, and drying the coating film. The properties of the coating liquid are not particularly limited as long as it can be applied, and may contain a component for forming the pressure-sensitive adhesive layer as a solute or as a dispersoid. The release sheet in this layered body may be peeled off as a process material, or may be used to protect the adhesive face of the pressure-sensitive adhesive layer until the sheet for work processing is attached to the work.

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

As described above, instead of transferring the pressure-sensitive adhesive layer formed on the release sheet to one side of the substrate, the pressure-sensitive adhesive layer may be formed directly on the substrate. In this case, the coating solution for forming the above-described pressure-sensitive adhesive layer is applied to one side of the substrate to form a coating film, and the coating film is dried to form the pressure-sensitive adhesive layer.

4. How to use the workpiece processing sheet

The sheet for processing a workpiece according to the present embodiment can be used for processing a workpiece. That is, after the adhesive surface of the workpiece processing sheet according to the present embodiment is attached to the workpiece, the workpiece can be processed on the workpiece processing sheet. According to the above processing, the workpiece processing sheet according to the present embodiment can be used as a back grind sheet, a dicing sheet, an expand sheet, a pick-up sheet, and the like. Here, as an example of a workpiece, semiconductor members, such as a semiconductor wafer and a semiconductor package, and glass members, such as a glass plate, are mentioned.

In addition, when the sheet|seat for work processing concerning this embodiment is provided with the adhesive layer mentioned above, the sheet|seat for work processing can be used as a dicing die-bonding sheet. In the case where the workpiece processing sheet according to the present embodiment includes the protective film forming layer described above, the workpiece processing sheet can be used as a protective film forming and dicing sheet.

In the sheet for work processing according to the present embodiment, the oxygen atom ratio R ₁₀₀ measured by X-ray photoelectron spectroscopy at a position at a depth of 100 nm from the adhesive surface among positions in the pressure-sensitive adhesive layer is within the above-mentioned range, and constitutes the pressure-sensitive adhesive layer. Even when the adhesive adheres to the workpiece after processing, the adhesive can be satisfactorily removed with running water. In addition, when the oxygen atom ratio R ₀ measured by X-ray photoelectron spectroscopy on the adhesive surface is within the above-mentioned range, the workpiece after processing can be easily separated. For this reason, the workpiece processing sheet according to the present embodiment is suitable for use in processing in which running water is used, and is particularly suitable for use in dicing involving supplying running water to the cut portion. That is, the workpiece processing sheet according to the present embodiment is preferably used as a dicing sheet.

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

[Manufacturing method of processed work]

A process for producing a processed workpiece according to an embodiment of the present invention includes a bonding step of bonding the workpiece to the surface on the opposite side to the base material in the pressure-sensitive adhesive layer of the above-described workpiece processing sheet, processing the workpiece on the workpiece processing sheet, A processing step of obtaining a processed workpiece laminated on a workpiece processing sheet, an irradiation step of irradiating the pressure-sensitive adhesive layer with active energy rays to cure the pressure-sensitive adhesive layer and reducing the adhesiveness of the workpiece processing sheet to the processed workpiece, and A separation step of separating the processed workpiece from the workpiece processing sheet after energy ray irradiation is provided.

In the workpiece processing sheet used in the manufacturing method of a processed workpiece of the present embodiment, even when the adhesive constituting the adhesive layer adheres to the processed workpiece, the adhesive agent can be satisfactorily removed with flowing water, and the processing sheet is processed. It becomes easy to separate the worked work well. For this reason, according to the manufacturing method of the processed workpiece of this embodiment, it becomes possible to manufacture a processed workpiece efficiently.

Hereinafter, each process in the manufacturing method of the processed workpiece of this embodiment is demonstrated.

(1) Bonding process

Bonding of the work piece and the sheet for work processing in the bonding step can be performed in accordance with a conventionally known method. Further, when performing dicing of the workpiece in the subsequent processing step, it is preferable to bond the ring frame to the area on the outer peripheral side of the area to which the workpiece is bonded on the surface of the pressure-sensitive adhesive layer side of the sheet for processing the workpiece. In addition, the workpiece to be used may be a desired one according to the processed workpiece to be manufactured, and as a specific example, the above-mentioned one can be used.

(2) Machining process

In the processing step, desired processing can be performed on the workpiece, for example, back grinding, dicing, and the like can be performed. This processing can be performed according to a conventionally well-known method.

In addition, when performing blade dicing using a rotating blade as said process, generally, a part of the adhesive layer in the sheet|seat for work processing is cut together with a workpiece. At this time, the adhesive constituting the adhesive layer may be rolled up by the blade and attached to the processed work. However, in the sheet for processing a workpiece used in the manufacturing method of a processed workpiece of the present embodiment, as described above, the adhered adhesive can be satisfactorily removed with running water. From this point of view, the processing in the present embodiment is preferably dicing, and blade dicing using rotating blades is particularly suitable.

(3) Irradiation process

In the irradiation step, the conditions for irradiation with active energy rays are not limited as long as the adhesive force of the workpiece processing sheet to the processed workpiece can be reduced to a desired degree, and it can be performed based on a conventionally known method. Examples of the type of active energy rays to be used include ionizing radiation, that is, X-rays, ultraviolet rays, electron beams, and the like, and among these, ultraviolet rays, which are relatively easy to introduce into an irradiation facility, are preferable.

(4) separation process

In the separation step, separation is performed according to the type of processing or the method according to the obtained processed work. For example, when dicing is performed as a process and chips formed by dividing the workpiece into pieces are obtained by the dicing, the obtained chips are individually picked up from the workpiece processing sheet using a conventionally known pick-up device. Further, in order to facilitate the pick-up, the sheet for processing the workpiece may be expanded to separate the processed workspieces.

(5) others

In the manufacturing method of the processed workpiece of this embodiment, you may provide processes other than the process mentioned above. For example, after the bonding step, you may provide a conveying step of conveying the obtained laminated body of the workpiece and the workpiece processing sheet to a predetermined position, a storage step of storing the laminated body for a predetermined period of time, or the like. Further, after the separation step, a mounting step or the like of mounting the obtained processed work to a predetermined base or the like may be provided.

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

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

Example

Hereinafter, the present invention will be described more specifically by examples and the like, but the scope of the present invention is not limited to these examples and the like.

[Example 1]

(1) Preparation of pressure-sensitive 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 It corresponds to 80 mol% with respect to the number of moles) of methacryloyloxyethyl isocyanate (MOI) was reacted to obtain an active energy ray-curable polymer. When the weight average molecular weight (Mw) of this active energy ray-curable polymer was measured by the method described later, it was 600,000.

100 parts by mass of the obtained active energy ray-curable polymer (in terms of solid content, the same hereinafter), 3 parts by mass of 1-hydroxycyclohexylphenylketone (manufactured by BASF, product name "IRGACURE 184") as a photopolymerization initiator, and toluene diisocyanate as a crosslinking agent ( TOSOH CORPORATION, product name "Coronate L") 9.32 parts by mass and active energy ray polymerizable branched polymer as an additive (manufactured by Nissan Chemical Industries, Ltd., product name "OD-007", weight average molecular weight: 14000) 0.18 parts by mass in a solvent By mixing, an adhesive composition was obtained.

(2) Formation of pressure-sensitive adhesive layer

The pressure-sensitive adhesive composition is 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 is formed on one side of a polyethylene terephthalate film having a thickness of 38 μm, and dried by heating. After that, by curing for 7 days under conditions of 23° C. and 50% RH, a pressure-sensitive adhesive layer having a thickness of 5 μm was formed on the release sheet.

(3) Manufacture of sheet for workpiece processing

The side opposite to the release sheet of the pressure-sensitive adhesive layer formed in the step (2) and one side of an 80 μm-thick ethylene-methacrylic acid copolymer (EMAA) film as a substrate were bonded together to obtain a sheet for work processing.

Here, the above-mentioned weight average molecular weight (Mw) is a weight average molecular weight in terms of standard polystyrene measured using gel permeation chromatography (GPC) (GPC measurement).

[Example 2 and Comparative Examples 1 to 3]

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

[Test Example 1] (measurement of oxygen atom ratio)

The release sheet was peeled off from the sheet for work processing prepared in Examples and Comparative Examples, and the oxygen atom ratio (%) on the exposed surface (adhesive surface) of the exposed pressure-sensitive adhesive layer and the pressure-sensitive adhesive layer at a depth of 100 nm from the exposed surface The oxygen atom ratio (%) in the inside was measured using an X-ray photoelectron spectroscopy device (manufactured by ULVAC-PHI, INCORPORATED, product name “PHI”Quantera”SXM”), and the oxygen atom ratio (%) at each “position of 0 nm” and oxygen atom ratio (%) at the "position of 100 nm". The results are shown in Table 1.

[Test Example 2] (measurement of adhesive force)

The release sheet was peeled off from the sheet for work processing produced in Examples and Comparative Examples, the exposed surface of the exposed pressure-sensitive adhesive layer was laminated on the mirror surface of a 6-inch silicon wafer subjected to mirror polishing, and a 2 kg roller was reciprocated once to apply a load. It was applied and bonded, and left to stand for 20 minutes to obtain a sample for measuring adhesive strength.

With respect to the sample for measuring the adhesive force, the sheet for work processing was peeled from the silicon wafer at a peeling rate of 300 mm/min and a peeling angle of 180 °, and in accordance with the 180 ° peeling method according to JIS Z0237: 2009, the adhesive force to the silicon wafer ( mN/25 mm) was measured. The results are shown in Table 1 as adhesive strength before ultraviolet irradiation (before UV).

[Test Example 3] (Evaluation of adhesive removability)

The release sheet was peeled off from the sheet for work processing produced in Examples and Comparative Examples, and the exposed surface of the exposed pressure-sensitive adhesive layer was polished with #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 affixed. Then, 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 portion under the following dicing conditions.

<Dicing conditions>

・Dicing device: DFD-6361 manufactured by DISCO Corporation

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

・Blade width 　　：0.025 ~ 0.030mm

・Amount of protruding knife tip 　　：0.640 ~ 0.760mm

・Blade rotation speed: 50000 rpm

·Cutting speed 　　　：20mm/sec

Notch depth: 15 μm from the surface of the pressure-sensitive adhesive layer side of the sheet for work processing

· Flowing water supply volume: 1.0L/min

・Temperature of running water = room temperature

・Cutting size: 10mm×10mm

Twenty chips obtained by the dicing were separated from the sheet for work processing, and it was visually confirmed whether or not an adhesive was adhered to them. And based on the following criteria, the removability of the adhesive was evaluated. The results are shown in Table 1.

○: The number of chips to which the adhesive was attached was 0.

x: The number of chips to which the adhesive was attached was one or more.

[Test Example 4] (Evaluation of separability)

Dicing was performed in the same manner as in Test Example 3 using the sheets for workpiece processing produced in Examples and Comparative Examples. After completion of dicing, the surface of the sheet for work processing is irradiated with ultraviolet rays (UV) using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2000") (illuminance: 230 mW/cm2, light amount: 190 mJ/cm2) ), the pressure-sensitive adhesive layer was cured. After that, all the obtained chips were picked up from the workpiece processing sheet. At this time, from the surface opposite to the surface on which the glass chips were attached in the workpiece processing sheet, protrusion was performed with a needle (number of needles: 4, protrusion speed: 50 mm/sec, protrusion height: 0.5 mm). Based on the pickup condition at this time, the separability at the time of separating the chips from the sheet for work processing was evaluated according to the following criteria. The results are shown in Table 1.

○: We were able to pick up without any problems.

x: Unsatisfactory pick-up was not possible due to separation of the chip or damage to the chip.

In addition, the details of the abbreviation and the like described in Table 1 are as follows.

BA: butyl acrylate

MMA: methyl methacrylate

MA: methyl acrylate

2MEA: 2-methoxyethyl acrylate

HEA: 2-hydroxyethyl acrylate

As can be seen from Table 1, according to the sheets for workpiece processing obtained in Examples, the adhesive could be satisfactorily removed with running water and the workpiece after processing could be separated satisfactorily.

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

Claims (6)

A sheet for work processing comprising a substrate and an adhesive layer laminated on one side of the substrate,
The pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive,
In the pressure-sensitive adhesive layer, the oxygen atom ratio R ₀ measured by X-ray photoelectron spectroscopy on the side opposite to the substrate is 28 atomic% or less,
Among the positions in the pressure-sensitive adhesive layer, the oxygen atom ratio R ₁₀₀ measured by X-ray photoelectron spectroscopy at a depth of 100 nm from the surface on the side opposite to the substrate in the pressure-sensitive adhesive layer is 20 atomic% or more and 29 atomic% or less Characterized by a sheet for work processing. According to claim 1,
The value of the oxygen atom ratio R ₀ is greater than the value of the oxygen atom ratio R ₁₀₀ ,
Equation (1)
Reduction rate (%) of oxygen atom ratio = {(Oxygen atom ratio R ₀ -Oxygen atom ratio R ₁₀₀ )/Oxygen atom ratio R ₀ ｝×100 . (One)
A sheet for work processing, characterized in that the reduction rate of the oxygen atom ratio calculated from is 0% or more and 15% or less. According to claim 1,
The active energy ray-curable pressure-sensitive adhesive is a pressure-sensitive adhesive formed of a pressure-sensitive adhesive composition containing an active energy ray-polymerizable branched polymer, characterized in that, a sheet for work processing. According to claim 3,
The pressure-sensitive adhesive composition contains an active energy ray-curable polymer obtained by reacting an acrylic copolymer having a functional group-containing monomer unit with an unsaturated group-containing compound having a functional group bonded to the functional group,
The acrylic copolymer contains 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: According to claim 1,
A sheet for work processing characterized in that it is a dicing sheet. A bonding step of bonding a surface of the pressure-sensitive adhesive layer of the sheet for processing a workpiece according to any one of claims 1 to 5 and a workpiece on the side opposite to the base material;
A processing step of processing the work on the work processing sheet to obtain a processed work laminated on the work processing sheet;
An irradiation step of irradiating the pressure-sensitive adhesive layer with active energy rays to cure the pressure-sensitive adhesive layer and reducing the adhesiveness of the workpiece processing sheet to the processed workpiece; and
a separation step of separating the processed workpiece from the workpiece processing sheet after irradiation with active energy rays;
Characterized in that it comprises a, manufacturing method of the processed work.