WO2019111481A1 - Workpiece machining sheet and production method for machined workpiece - Google Patents

Abstract

A workpiece machining sheet comprising a base material and an adhesive layer laminated on one surface side of the base material. The workpiece machining sheet is characterized by: the adhesive layer comprising an active energy ray curable adhesive; the oxygen atom ratio R0 being no more than 28 atom%, as measured by X ray photoelectron spectroscopy on a surface on the opposite side of the adhesive layer to the base material; and the oxygen atom ratio R100 being 20–29 atom%, as measured by X ray photoelectron spectroscopy at a position in the adhesive layer that is at a depth of 100 nm from the surface on the opposite side of the adhesive layer to the base material. Said workpiece machining sheet can adequately remove the adhesive by using running water and can adequately separate the workpiece after machining, said adhesive being derived from the adhesive layer attached to the workpiece after machining.

Description

Sheet for work processing and manufacturing method of 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 such as silicon and gallium arsenide and various packages (hereinafter, these may be collectively referred to as "objects to be cut") are manufactured in a large diameter state, and these are element chips (hereinafter, "elements" After being separated (dicing) and separated (picked up) individually into chips, they are transferred to the next step, the mounting step. At this time, a workpiece such as a semiconductor wafer is subjected to dicing, cleaning, drying, expanding, pickup and mounting steps in a state of being attached to a work processing sheet provided with a base material and an adhesive layer. Ru.

In the above-described dicing process, the dicing blade, the workpiece and the work processing sheet are heated by the frictional heat generated between the rotating dicing blade and the workpiece or the work processing sheet. In addition, in the dicing process, a cut piece may be generated from a workpiece or a work processing sheet, which may adhere to a chip.

Therefore, when performing the dicing step, usually, flowing water is supplied to the cutting portion to cool the dicing blade and the like, and the generated cutting pieces are removed from the chips.

Patent Document 1 discloses that the contact angle to pure water of the surface of the pressure-sensitive adhesive layer on the side opposite to the base material before ultraviolet irradiation is 82 ° to 114 ° for the purpose of promoting the removal of the cutting pieces by the flowing water. There is disclosed a work processing sheet having a contact angle of 44 ° to 64 ° to methylene iodide and a peak value of probe tack test of 294 to 578 kPa in the pressure-sensitive adhesive layer before ultraviolet irradiation. .

Patent No. 5019657

However, when performing a dicing process using a conventional work processing sheet as disclosed in Patent Document 1, the pressure-sensitive adhesive derived from the pressure-sensitive adhesive layer of the work processing sheet is sufficiently removed from the work after processing I could not do it.

Also, in general, when the chip is separated from the work processing sheet in the pick-up process, it can be separated without requiring an excessive force, and it is therefore required that no defect such as breakage of the chip occurs. .

The present invention has been made in view of such a situation, and the adhesive derived from the pressure-sensitive adhesive layer attached to the workpiece after processing can be favorably removed by flowing water, and the workpiece after processing is It is an object of the present invention to provide a work processing sheet capable of being favorably separated, and a method of manufacturing a processed work using the work processing sheet.

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

In the work processing sheet according to the invention (Invention 1), the oxygen atom ratio measured by X-ray photoelectron spectroscopy analysis on the surface of the pressure-sensitive adhesive layer opposite to the substrate (hereinafter sometimes referred to as "pressure-sensitive surface"). When R ₀ is 28 atomic% or less, the adhesive surface has appropriate hydrophobicity, and the work after processing can be easily separated. In addition, the oxygen atom ratio R ₁₀₀ measured by X-ray photoelectron spectroscopy at a position 100 nm deep from the adhesive surface among the positions in the pressure-sensitive adhesive layer is 20 atomic% or more and 29 atomic% or less. In the pressure-sensitive adhesive attached to the work, the surface thereof has appropriate hydrophilicity, and the pressure-sensitive adhesive attached to the work after processing can be favorably removed by running water.

In the above invention (Invention 1), the value of the oxygen atom ratio R ₀ is larger than the value of the oxygen atom ratio R ₁₀₀ , and 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 (1)
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), the active energy ray-curable adhesive is preferably an adhesive formed from an adhesive composition containing an active energy ray polymerizable branched polymer (Invention 3) .

In the above inventions (Inventions 1 to 3), the pressure-sensitive adhesive composition is prepared by reacting an acrylic copolymer having a functional group-containing monomer unit with an unsaturated group-containing compound having a functional group to be bonded to the functional group. And the acrylic copolymer comprises, as monomer units constituting the polymer, methyl acrylate, 2-methoxyethyl (meth) acrylate, (meth ) It is preferable to include at least one selected from ethyl carbitol acrylate and methoxy ethylene glycol (meth) acrylate (Invention 4).

In the above inventions (Inventions 1 to 4), a dicing sheet is preferable (Invention 5).

Second, the present invention provides a bonding step of bonding a work with the surface of the pressure-sensitive adhesive layer opposite to the base in the work processing sheet (inventions 1 to 5), and the work processing A processing step of obtaining a processed work laminated on the work processing sheet by processing the work on a sheet, and irradiating the pressure-sensitive adhesive layer with an active energy ray, the pressure-sensitive adhesive layer And a separation step of separating the processed work from the work processing sheet after irradiation with an active energy ray, and curing the work processing sheet to lower the adhesion of the work processing sheet to the processed work. The present invention provides a method of manufacturing a processed work characterized by

The sheet for processing a work according to the present invention can remove well the adhesive derived from the pressure-sensitive adhesive layer attached to the work after processing by flowing water, and can separate the work after processing well. . Moreover, according to the method of manufacturing a processed work according to the present invention, it is possible to efficiently manufacture the processed work.

Hereinafter, embodiments of the present invention will be described.
[Workpiece processing sheet]
The work processing sheet according to the present embodiment includes a base, and a pressure-sensitive adhesive layer laminated on one side of the base.

1. Physical Properties of Sheet for Processing of Workpiece In the sheet for work processing according to the present embodiment, the oxygen atom ratio R ₀ measured by X-ray photoelectron spectroscopy analysis on the surface (adhesive surface) opposite to the substrate in the pressure-sensitive adhesive layer is 28 It is less than atomic percent. When the oxygen atom ratio R ₀ is 28 atomic% or less, the adhesive surface has appropriate hydrophobicity, and the adhesion to the workpiece after processing of the work processing sheet is prevented from being excessively high. . This makes it possible to satisfactorily separate the processed work from the work processing sheet. In particular, when a silicon wafer is used as a work, relatively many hydrophilic groups are present on the surface of the silicon wafer, and an adhesive surface having appropriate hydrophobicity is in contact with this surface. Thus, the workpiece after machining can be easily separated. In addition, the detail of the measuring method of oxygen atom ratio _R0 mentioned above is as being described in the test example mentioned later.

When the oxygen atom ratio R ₀ described above exceeds 28 atomic%, the adhesive surface has relatively high hydrophilicity, and the adhesion to the workpiece after processing of the work processing sheet is excessively high. In this case, an excessive force is required to separate the processed work from the work processing sheet, which may cause problems such as breakage of the processed work. From the viewpoint of avoiding such a problem, the oxygen atom ratio R ₀ is preferably 27 atomic% or less.

The oxygen atom ratio R ₀ is preferably 20 atomic percent or more, and more preferably 22 atomic percent or more. When the oxygen atom ratio R ₀ is 20 atomic% or more, the hydrophilicity on the adhesive surface becomes appropriate, and the sheet for processing a work becomes easy to exhibit good adhesion to the work. Thereby, it is possible to effectively suppress unintended peeling of the workpiece before or after processing, when processing a workpiece or when transporting a workpiece or a workpiece after processing onto a workpiece processing sheet in a stacked state, etc. It becomes.

In the work processing sheet according to the present embodiment, the oxygen atom ratio R ₁₀₀ measured by X-ray photoelectron spectroscopy at a position 100 nm deep from the adhesive surface among the positions in the pressure-sensitive adhesive layer is 20 atomic% or more and 29 atomic%. % Or less. As a result, the pressure-sensitive adhesive in the pressure-sensitive adhesive layer has appropriate hydrophilicity.

Generally, in the case of dicing using a dicing blade, a rotating dicing blade is applied to an object to be cut while supplying flowing water to the cutting portion to cut the object to be cut. At this time, the rotating dicing blade may contact not only the workpiece but also the pressure-sensitive adhesive layer. In such a contact portion, cutting of the pressure-sensitive adhesive layer or rolling up of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer by a dicing blade occurs, and as a result, a small piece of the pressure-sensitive adhesive is formed. The small pieces adhere to an object to be cut and a formed chip, which adversely affects the handling of the chip thereafter, and causes deterioration of the quality of the chip and the product on which the chip is mounted. Here, since the small pieces of the pressure-sensitive adhesive are formed as described above, most of the small pieces are present inside the pressure-sensitive adhesive layer when the pressure-sensitive adhesive layer is formed.

In the work processing sheet according to the present embodiment, as described above, since the pressure-sensitive adhesive inside the pressure-sensitive adhesive layer has appropriate hydrophilicity, small pieces of the pressure-sensitive adhesive as described above during processing Even when the small pieces adhere to the workpiece (chip or the like) after processing, the surface of the small pieces has appropriate hydrophilicity. Therefore, according to the work processing sheet according to the present embodiment, the adhesive attached to them can be favorably removed from the work after processing by flowing water supplied at the time of processing.

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

In addition, when the oxygen atom ratio R ₁₀₀ described above exceeds 29 atomic%, the pressure-sensitive adhesive in the pressure-sensitive adhesive layer exhibits excessive affinity to water, and accordingly, the water on the surface of the pressure-sensitive adhesive layer is also High affinity for As a result, it is not possible to suppress the infiltration of water, and chip jumping and chipping occur during dicing. From the viewpoint of avoiding such a problem, the oxygen atom ratio R ₁₀₀ described above is preferably 27 atomic% or less. The details of the measurement method of the oxygen atomic ratio R _100, are as described in Test Examples below.

In the work processing sheet according to the present embodiment, the value of the oxygen atom ratio R ₁₀₀ is larger 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 fall within the above-described ranges. The oxygen atom ratio R ₀ may be larger than the oxygen atom ratio R ₁₀₀ . Alternatively, the oxygen atom ratio R ₀ and the oxygen atom ratio R ₁₀₀ may have the same value. 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 (1)
The reduction rate of the oxygen atom ratio calculated from is preferably 0% or more, particularly preferably 1% or more, and further preferably 2% or more. Further, the reduction rate is preferably 15% or less, particularly preferably 12% or less, and further preferably 10% or less. When the reduction rate of the oxygen atom ratio is in the above-mentioned range, it becomes easy to simultaneously achieve both removal of the adhesive favorably by flowing water and good separation of the processed work from the work processing sheet. .

In the work processing sheet according to the present embodiment, the adhesion of the work processing sheet to the silicon wafer is preferably 1000 mN / 25 mm or more, particularly preferably 1200 mN / 25 mm or more, and further preferably 1500 mN / 25 mm or more Is preferred. The adhesive strength in this case refers to the adhesive strength in the state where the active energy ray is not irradiated to the work processing sheet and the adhesive layer is not cured. Further, the "adhesive force" described without mentioning the presence or absence of the irradiation of active energy rays throughout the present specification is also not irradiating the active energy rays to the work processing sheet, and the pressure-sensitive adhesive layer The adhesive strength in the state where the curing of the When the adhesive strength described above is 1000 mN / 25 mm or more, the workpiece to be processed can be easily held on the workpiece processing sheet, and the workpiece during processing, or the workpiece after processing is on the workpiece processing sheet Peeling of the workpiece before or after processing when transported in a state of being stacked on top of one another can be favorably suppressed. In particular, when the workpiece after processing is a chip, scattering of the chip from the workpiece processing sheet can be favorably suppressed.

The adhesion of the work 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 strength is 5000 mN / 25 mm or less, the adhesive strength after irradiation of the active energy ray can be easily adjusted to the range described later. In addition, the detail of the measuring method of the adhesive force with respect to the silicon wafer of the sheet | seat for workpiece | work is as having described in the test example mentioned later.

In the work processing sheet according to the present embodiment, it is preferable that the adhesion of the work processing sheet to the silicon wafer after the work processing sheet is irradiated with the active energy ray is 65 mN / 25 mm or less. When the adhesion is 65 mN / 25 mm or less, it is easier to separate the processed work from the work processing sheet by irradiating the work processing sheet with active energy rays after the processing of the work is completed. Become.

2. Constituent member of work processing sheet (1) base material In the work processing sheet according to the present embodiment, the base material exerts a desired function in the process of using the work processing sheet, and preferably, the adhesive layer is cured There is no particular limitation as long as it exhibits good permeability to the active energy ray irradiated.

For example, the substrate is preferably a resin film mainly composed of a resin material, and as a specific example thereof, an ethylene-vinyl acetate copolymer film; an ethylene- (meth) acrylic acid copolymer film, Ethylene-based copolymer films such as ethylene- (meth) acrylate copolymer film and other ethylene- (meth) acrylate copolymer films; polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene Films, ethylene-norbornene copolymer films, polyolefin films such as norbornene resin film; polyvinyl chloride films such as polyvinyl chloride film, vinyl chloride copolymer film; polyethylene terephthalate film, polybutylene tere (Meth) acrylic acid ester copolymer film; polyurethane film; polyimide film; polystyrene films; polycarbonate films; tallate film, polyester films such as polyethylene naphthalate and a fluorine resin film. Examples of polyethylene films include low density polyethylene (LDPE) films, linear low density polyethylene (LLDPE) films, high density polyethylene (HDPE) films, and the like. In addition, modified films such as these crosslinked films and ionomer films are also used. Moreover, the base material may be a laminated film in which a plurality of the films described above are laminated. In this laminated film, the materials constituting each layer may be the same or different. Among the above-mentioned films, it is preferable to use an ethylene-methyl methacrylate copolymer film as the substrate 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 a flame retardant, a plasticizer, an antistatic agent, a lubricant, an antioxidant, a colorant, an infrared absorber, an ultraviolet absorber, an ion scavenger and the like. The content of these additives is not particularly limited, but it is preferable to set the range in which the substrate exhibits a desired function.

The surface of the base on which the pressure-sensitive adhesive layer is to be laminated may be subjected to surface treatment such as primer treatment, corona treatment, plasma treatment, etc., in order to enhance adhesion with the pressure-sensitive adhesive layer.

Although the thickness of the substrate can be appropriately set depending on the method in which the work processing sheet is used, in general, the thickness is preferably 20 μm or more, and particularly preferably 25 μm or more. The thickness is usually preferably 450 μm or less, particularly preferably 300 μm or less.

(2) Pressure-Sensitive Adhesive Layer In the work processing sheet according to the present embodiment, the pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive, and can exert desired adhesive strength and the oxygen atom ratio described above There are no particular limitations as long as R ₀ and the oxygen atom ratio R ₁₀₀ fall within the ranges described above.

In the work processing sheet according to the present embodiment, the pressure-sensitive adhesive layer is formed of an active energy ray-curable pressure-sensitive adhesive, whereby the work after processing attached to the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer and the pressure-sensitive adhesive surface When separating the sheet, the pressure-sensitive adhesive layer can be cured by active energy ray irradiation to reduce the adhesion to the work after processing of the work-processing sheet. This facilitates separation of the adhesive surface of the pressure-sensitive adhesive layer and the work after processing.

The pressure-sensitive adhesive layer in the present embodiment may be formed from a pressure-sensitive adhesive composition containing a polymer having active energy ray curability, or an active energy ray non-curable polymer (active energy ray curability may be used. It may be formed from a pressure-sensitive adhesive composition containing a polymer (not having a polymer) and a monomer and / or an oligomer having at least one active energy ray-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.

A polymer having active energy ray curability has a (meth) acrylic acid ester (co) polymer (A) (hereinafter referred to as) having a functional group (active energy ray curable group) having active energy ray curability in the side chain. It is preferable that it is "an active energy ray curable polymer (A)." The active energy ray-curable polymer (A) comprises an acrylic copolymer (a1) having a functional group-containing monomer unit and an unsaturated group-containing compound (a2) having a functional group to be bonded to the functional group. It is preferable that it is obtained by making it react.

The acrylic copolymer (a1) may be referred to as a monomer for adjusting the hydrophilicity of the acrylic copolymer (a1) as a monomer unit constituting the polymer (hereinafter referred to as a "hydrophilic adjusting monomer". In particular, methyl acrylate, 2-methoxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate (ethoxyethoxyethyl (meth) acrylate) and It is preferable to include at least one selected from methoxy ethylene glycol acrylates.

In the pressure-sensitive adhesive sheet according to the present embodiment, the use of the hydrophilicity-adjusting monomer described above for the acrylic copolymer (a1) makes it easy to adjust the oxygen atom ratio R ₁₀₀ to the above-described range. The reason for this is that many of the above-mentioned hydrophilicity-adjusting monomers have a relatively large number of oxygen atoms, and by using an acrylic copolymer (a1) composed of the monomers, the pressure-sensitive adhesive layer It is considered that the absolute amount of oxygen atoms also increases, which makes it easy to adjust the oxygen atom ratio R ₁₀₀ to the above-mentioned range. However, it is not limited only to the said reason.

From the viewpoint of easily adjusting the above-mentioned oxygen atom ratio R ₁₀₀ to the above-mentioned range, the acrylic copolymer (a1) is, among the above-mentioned monomers as a monomer unit constituting the polymer, methyl acrylate, It is preferable to include at least one of 2-methoxyethyl acrylate and methoxy ethylene glycol acrylate.

When the acrylic copolymer (a1) contains methyl acrylate as a monomer unit constituting a polymer, the content of methyl acrylate is preferably 10% by mass or more, and particularly preferably 20% by mass or more Is more preferable, and 30% by mass or more is more preferable. Moreover, it is preferable that content of methyl acrylate is 85 mass% or less. With these contents, in the pressure-sensitive adhesive layer to be formed, the above-described oxygen atom ratio R ₁₀₀ can be easily adjusted in the above-described range. In addition, in this specification, content (mass%) of the methyl acrylate mentioned above means content with respect to the all monomers which comprise an acryl-type copolymer (a1). In addition, the content (% by mass) of other monomers described later is also meant to be the content with respect to all the monomers constituting the acrylic copolymer (a1).

When the acrylic copolymer (a1) contains 2-methoxyethyl acrylate as a monomer unit constituting a polymer, the content of 2-methoxyethyl acrylate is preferably 10% by mass or more, In particular, the content is preferably 20% by mass or more, and more preferably 30% by 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 further preferably 70% by mass or less. With these contents, in the pressure-sensitive adhesive layer to be formed, the above-described oxygen atom ratio R ₁₀₀ can be easily adjusted in the above-described range.

When the acrylic copolymer (a1) contains both methyl acrylate and 2-methoxyethyl acrylate as monomer units constituting the polymer, the content of methyl acrylate and 2-methoxyethyl acrylate is The total value is preferably 10% by mass or more, particularly preferably 30% by mass or more, and further preferably 50% by mass or more. Moreover, it is preferable that the said sum total is 90 mass% or less, and it is preferable that it is especially 85 mass% or less. It becomes easy to adjust the oxygen atom ratio R ₁₀₀ mentioned above by the range mentioned above in the adhesive layer formed because the said total value is these ranges.

Furthermore, when the acrylic copolymer (a1) contains methoxyethylene glycol acrylate as a monomer unit constituting a polymer, the content of methoxyethylene glycol acrylate is preferably 10% by mass or more, and particularly preferably 30. It is preferable that it is mass% or more. Further, the content of methoxyethylene glycol acrylate is preferably 90% by mass or less, and particularly preferably 85% by mass or less. With these contents, in the pressure-sensitive adhesive layer to be formed, the above-described oxygen atom ratio R ₁₀₀ can be easily adjusted in the above-described range.

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

The functional group-containing monomer as a constituent unit of the acrylic copolymer (a1) has, in its molecule, a polymerizable double bond and a functional group such as a hydroxy group, a carboxy group, an amino group, a substituted amino group or an epoxy group. Among these, it is preferable to contain at least one of a hydroxy group-containing monomer, an amino group-containing monomer and a substituted amino group-containing monomer.

Examples of the above-mentioned hydroxy group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, Examples thereof include 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and the like, and these can be used alone or in combination of two or more.

Examples of the amino group-containing monomer or the substituted amino group-containing monomer include aminoethyl (meth) acrylate and n-butylaminoethyl (meth) acrylate. These may be used alone or in combination of two or more.

Examples of carboxy group-containing monomers include ethylenic unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid and citraconic acid, which may be used alone. Two or more may be used in combination. However, it is preferable that the acrylic copolymer (a1) does not contain a carboxy group-containing monomer. When the acrylic copolymer (a1) does not contain a carboxy group-containing monomer, adjustment of the water contact angle becomes easier.

The acrylic copolymer (a1) preferably contains 1% by mass or more, particularly preferably 5% by mass or more, and further preferably 10% by mass or more of the structural unit derived from the functional group-containing monomer. It is preferable to do. The acrylic copolymer (a1) preferably contains 35% by mass or less, and particularly preferably 30% by mass or less, of the constituent unit derived from the functional group-containing monomer.

As a (meth) acrylic acid ester monomer which comprises an acryl-type copolymer (a1), in addition to the (meth) acrylic-acid alkylester whose carbon number of an alkyl group is 1-20, for example, it is alicyclic in the molecule | numerator A monomer having a structure (alicyclic structure-containing monomer) is preferably used.

As the (meth) acrylic acid alkyl ester, (meth) acrylic acid alkyl ester having, in particular, an alkyl group having 1 to 18 carbon atoms, such as methyl methacrylate, ethyl (meth) acrylate, propyl (meth) acrylate, N-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and the like are preferably used. One of these may be used alone, or two or more of these may be used in combination.

Examples of the alicyclic structure-containing monomer include cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, adamantyl (meth) acrylate, isobornyl (meth) acrylate, and dicyclopentenyl (meth) acrylate. And dicyclopentenyl oxyethyl (meth) acrylate are preferably used. One of these may be used alone, or two or more of these may be used in combination.

Furthermore, the acrylic copolymer (a1) preferably contains 50% by mass or more, and particularly preferably 60% by mass or more of structural units derived from the (meth) acrylic acid ester monomer or its derivative. Furthermore, it is preferable to contain 70 mass% or more. The acrylic copolymer (a1) preferably contains a constituent unit derived from a (meth) acrylic acid ester monomer or a derivative thereof at 99% by mass or less, and particularly preferably at 95% by mass or less Preferably, the content is further 90% by mass or less.

The acrylic copolymer (a1) is preferably obtained by copolymerizing the above-mentioned hydrophilicity adjusting monomer, a functional group-containing monomer, and a (meth) acrylic acid ester monomer or a derivative thereof in a conventional manner In addition to these monomers, dimethyl acrylamide, vinyl formate, vinyl acetate, styrene or the like may be copolymerized.

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

The functional group which an unsaturated group containing compound (a2) has can be suitably selected according to the kind of functional group of the functional group containing monomer unit which an acryl-type copolymer (a1) has. For example, when the functional group possessed by the acrylic copolymer (a1) is a hydroxy group, an amino group or a substituted amino group, an isocyanate group or an epoxy group is preferable as the functional group possessed by the unsaturated group-containing compound (a2). When the functional group possessed by the copolymer (a1) is an epoxy group, the functional group possessed by the unsaturated group-containing compound (a2) is preferably an amino group, a carboxy group or an aziridinyl group.

The above unsaturated group-containing compound (a2) contains at least one, preferably 1 to 6, and more preferably 1 to 4 active energy ray-polymerizable carbon-carbon double bonds in one molecule. It is done. Specific examples of such unsaturated group-containing compound (a2) include 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α, α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1- Bisacryloyloxymethyl) ethyl isocyanate; acryloyl monoisocyanate compound obtained by reaction of diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth) acrylate; diisocyanate compound or polyisocyanate compound, polyol compound, (meth) acrylic acid Acryloyl monoisocyanate compounds obtained by reaction with hydroxyethyl acid; glycidyl (meth) acrylate; (meth) acrylic acid, (meth) acrylic acid Examples include 2- (1-aziridinyl) ethyl succinate, 2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline and the like.

The above-mentioned unsaturated group-containing compound (a2) is preferably at least 50 mol%, particularly preferably at least 60 mol%, more preferably with respect to the number of moles of the functional group-containing monomer of the acrylic copolymer (a1). It is used in the ratio of 70 mol% or more. The unsaturated group-containing compound (a2) is preferably 95 mol% or less, particularly preferably 93 mol% or less, based on the number of moles of the functional group-containing monomer of the acrylic copolymer (a1). Preferably, it is used in a proportion of 90 mol% or less.

In the reaction of the acrylic copolymer (a1) with the unsaturated group-containing compound (a2), the functional group of the acrylic copolymer (a1) and the functional group of the unsaturated group-containing compound (a2) Depending on the combination, the reaction temperature, pressure, solvent, time, presence or absence of catalyst, and type of catalyst can be appropriately selected. Thereby, the functional group present in the acrylic copolymer (a1) and the functional group in the unsaturated group-containing compound (a2) react with each other, and the unsaturated group in the acrylic copolymer (a1) It is introduced into a side chain to obtain an active energy ray-curable polymer (A).

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. Preferably there. Further, the weight average molecular weight (Mw) is preferably 1.5 million or less, and particularly preferably 1 million or less. In addition, the weight average molecular weight (Mw) in this specification is a value of standard polystyrene conversion measured by the gel permeation chromatography method (GPC method).

Even when the pressure-sensitive adhesive composition in the present embodiment contains a polymer having an active energy ray-curable property such as an active energy ray-curable polymer (A), the pressure-sensitive adhesive composition has an active energy ray-curable property. The monomers and / or the oligomers (B) of

As the active energy ray-curable monomer and / or oligomer (B), for example, an ester of 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, trimethylolpropane tri (meth) acrylate, Pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, polyethylene Multifunctional acrylic acid esters such as glycol di (meth) acrylate and dimethylol tricyclodecane di (meth) acrylate, polyester oligo (meth) acrylate, polyurethane oligo ( Data) acrylate, and the like.

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

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

Specific examples of the photopolymerization initiator (C) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, methyl benzoin benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, tetramethyl thiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloroanthraquinone, (2,4, 6-trimethylbenzyl diphenyl) phosphine oxide, 2-benzothiazole-N, N-diethyldithiocarbamate, oligo {2-hydroxy-2-me Le-1- [4- (1-propenyl) phenyl] propanone}, and 2,2-dimethoxy-1,2-and the like. These may be used alone or in combination of two or more.

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

The pressure-sensitive adhesive composition in the present embodiment preferably contains an additive (D) for adjusting the oxygen atom ratio in the pressure-sensitive adhesive layer. Examples of such additives include active energy ray polymerizable branched polymers, branched polymers, epoxy resins and the like, and among these, it is easy to adjust the oxygen atom ratio in the pressure-sensitive adhesive layer to a desired range. From the viewpoint, it is preferable to use an active energy ray-polymerizable branched polymer.

The active energy ray polymerizable branched polymer is a kind 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 this embodiment is formed of a pressure-sensitive adhesive composition containing an active energy ray-polymerizable branched polymer, so that the oxygen atom ratio R ₀ measured by X-ray photoelectron spectroscopy on the pressure-sensitive adhesive surface is 28. Adjustment to atomic% or less is easy. As this reason, although it is not limited to it, the following is considered. When forming a pressure-sensitive adhesive layer using a pressure-sensitive 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. Therefore, in the formed pressure-sensitive adhesive layer, the content of the active energy ray polymerizable branched polymer is more present in the portion closer to the surface than in the inside. Here, since the active energy ray polymerizable branched polymer itself is a component having a relatively small oxygen atom ratio, an oxygen atom of 28 atomic% or less on the adhesive surface where more active energy ray polymerizable branched polymers are present It is easy to achieve the ratio.

Further, since the active energy ray polymerizable branched polymer has an active energy ray polymerizable group, when the work processing sheet is irradiated with the active energy ray, the active energy ray polymerizable branched polymers or each other are activated. It is possible to carry out a polymerization reaction between the energy beam polymerizable branched polymer and the component having an active energy ray curable group, thereby suppressing the transfer of the active energy beam polymerizable branched polymer to the work after processing At the same time, the pressure-sensitive adhesive layer after the active energy ray irradiation is further hardened, and it becomes easy to effectively separate the processed work from the work processing sheet.

As described above, the active energy ray polymerizable branched polymer has a specific structure (for example, the degree of the branched structure, active energy possessed in one molecule) as long as the polymer has an active energy ray polymerizable group and a branched structure. The number of linear polymerizable groups) is not particularly limited. As a method of obtaining such an active energy ray polymerizable branched polymer, for example, a monomer having two or more radically polymerizable double bonds in the molecule, an active hydrogen group and one radically polymerizable double bond And a polymer having a branched structure, obtained by polymerizing a monomer having in the molecule thereof and a monomer having one radically polymerizable double bond in the molecule, and reacting with an active hydrogen group to form a bond It can be obtained by reacting a compound having a possible functional group and at least one radically polymerizable double bond in the molecule. The three monomers described above may each be (meth) acrylic acid ester or (meth) acrylic acid, and in this case, the active energy ray polymerizable branched polymer becomes an acrylic polymer.

The weight average molecular weight of the active energy ray polymerizable branched polymer is preferably 1,000 or more, and particularly preferably 3,000 or more. Further, the weight average molecular weight is preferably 100,000 or less, and particularly preferably 30,000 or less. When the weight average molecular weight is in the above-mentioned range, the oxygen atom ratio R ₀ measured by X-ray photoelectron spectroscopy on the adhesive surface can be easily adjusted 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 the active energy ray-curable monomer and / or oligomer (B) is blended) And 0.05 parts by mass or more based on 100 parts by mass of the total amount of the active energy ray curable polymer (A) and the active energy ray curable monomer and / or oligomer (B), particularly preferably It is preferable that it is 0.1 mass part or more. In addition, the content is 100 parts by mass of the active energy ray-curable polymer (A) (when the active energy ray-curable monomer and / or oligomer (B) is blended, the active energy ray-curable polymer ( It is preferably 1 part by mass or less, and particularly preferably 0.5 parts by mass or less, based on 100 parts by mass of the total amount of A) and the monomer and / or oligomer (B) curable by active energy rays. . When the content of the additive (D) is in the above-described range, the oxygen atom ratio in the pressure-sensitive adhesive layer can be easily adjusted to the desired range.

In addition to the components described above, the pressure-sensitive adhesive composition in the present embodiment may appropriately contain other components. As another component, an active energy ray non-curable polymer component or oligomer component (E), a crosslinking agent (F) etc. are mentioned, for example.

Examples of the active energy ray non-curable polymer component or oligomer component (E) include polyacrylic acid ester, polyester, polyurethane, polycarbonate, polyolefin and the like, and a polymer having a weight average molecular weight (Mw) of 3,000 to 2,500,000 or Oligomers are preferred. By blending the component (E) into the active energy ray-curable pressure-sensitive adhesive, it is possible to improve the tackiness and peelability before curing, the strength after curing, the adhesiveness with other layers, the storage stability and the like. The compounding quantity of the said component (E) is not specifically limited, With respect to 100 mass parts of active energy ray curable polymers (A), it determines suitably in more than 0 mass part and 50 mass parts or less.

As a crosslinking agent (F), the polyfunctional compound which has the reactivity with the functional group which the active energy ray curable polymer (A) etc. have can be used. Examples of such polyfunctional compounds include isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, oxazoline compounds, metal alkoxide compounds, metal chelate compounds, metal salts, ammonium salts, Reactive phenol resin etc. can be mentioned.

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

Next, the pressure-sensitive adhesive layer in the present embodiment is formed from 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. The following describes the case of

As the active energy ray non-curable polymer component, for example, the same component as 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, the same one as the component (B) described above can be selected. The compounding ratio of the active energy ray non-curable polymer component to the monomer and / or oligomer having at least one or more active energy ray curable groups is at least 1 with respect to 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 which has two or more active energy ray curable groups, and it is especially preferable that it is 60 mass parts or more. In addition, the compounding ratio is preferably 200 parts by mass or less of a monomer and / or oligomer having at least one or more active energy ray-curable groups with respect to 100 parts by mass of the active energy ray non-curable polymer component, In particular, the amount is preferably 160 parts by mass or less.

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

The pressure-sensitive adhesive layer is preferably 1 μm or more, and particularly preferably 5 μm or more. Further, the thickness is preferably 50 μm or less, and particularly preferably 40 μm or less. When the thickness of the pressure-sensitive adhesive layer is in the above range, desired adhesion to a work can be easily achieved.

(3) Release sheet In the work processing sheet according to this embodiment, the release sheet is laminated on the surface for the purpose of protecting the surface until the adhesive surface of the pressure-sensitive adhesive layer is attached to the work. Good. The configuration of the release sheet is optional, and examples thereof include those obtained by release treatment of a plastic film with a release agent or the like. Specific examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. As the release agent, silicone type, fluorine type, long chain alkyl type and the like can be used, and among these, silicone type is preferable because inexpensive and stable performance can be obtained. 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 work processing sheet according to the present embodiment, an adhesive layer may be laminated on the adhesive surface of the adhesive layer. In this case, the work processing sheet according to the present embodiment can be used as a dicing / die bonding sheet by providing the adhesive layer as described above. In such a work processing sheet, a work is attached to the surface of the adhesive layer opposite to the pressure-sensitive adhesive layer, and the adhesive layer is singulated by dicing the adhesive layer together with the work. Chips can be obtained. The chip can be easily fixed to an object on which the chip is mounted by the separated adhesive layer. As a material constituting the adhesive layer described above, a material containing a thermoplastic resin and a thermosetting adhesive component having a low molecular weight, a material containing a B-stage (semi-hardened) thermosetting adhesive component, etc. It is preferred to use.

Moreover, in the sheet | seat for work processing which concerns on this embodiment, a protective film formation layer may be laminated | stacked on the adhesive surface in an adhesive layer. In this case, the work processing sheet according to the present embodiment can be used as a protective film forming and dicing sheet. In such a work processing sheet, a work is attached to the surface of the protection film formation layer opposite to the pressure-sensitive adhesive layer, and the protection film formation layer is diced together with the work to form a protection film separated into pieces. A chip with stacked layers can be obtained. As the work, one having a circuit formed on one side is preferably used. In this case, a protective film forming layer is usually laminated on the side opposite to the side on which the circuit is formed. The protective film forming layer separated into pieces can be cured at a predetermined timing to form a protective film having sufficient durability on the chip. The protective film-forming layer preferably comprises an uncured curable adhesive.

The work processing sheet according to the embodiment of the present invention has the oxygen atom ratio R ₀ and the oxygen atom ratio R ₁₀₀ in the above-mentioned ranges, but the adhesive layer or the protective film described above for the pressure-sensitive adhesive layer When the formation layer is laminated, the oxygen atom ratio R ₀ and the oxygen atom ratio R ₁₀₀ may be in the above-mentioned ranges, respectively, for the pressure-sensitive adhesive layer before these layers are laminated.

3. Method of Manufacturing Sheet for Processing of Work The method of manufacturing a sheet for processing of work according to the present embodiment is not particularly limited. Preferably, the sheet for processing of work according to the present embodiment has a pressure-sensitive adhesive layer laminated on one side of a substrate. It is manufactured by doing.

The lamination of the pressure-sensitive adhesive layer on one side of the substrate can be carried out by 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 substrate. In this case, a pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer, and optionally a coating liquid containing a solvent or a dispersion medium if desired, may be referred to as a release-treated surface (hereinafter referred to as "release surface" The above coating solution is applied on a die coater, curtain coater, spray coater, slit coater, knife coater or the like to form a coating film, and the coating film is dried to form a pressure-sensitive adhesive layer. be able to. The coating liquid is not particularly limited in its properties as long as it can be applied, and may contain a component for forming a pressure-sensitive adhesive layer as a solute or a dispersoid. The release sheet in this laminate may be released as a process material or may be used to protect the adhesive surface of the pressure-sensitive adhesive layer until the work processing sheet is attached to the work.

When the coating liquid for forming the pressure-sensitive adhesive layer contains a crosslinking agent, the inside of the coating film can be obtained by changing the above-mentioned drying conditions (temperature, time, etc.) or by separately providing a heat treatment. The crosslinking reaction of the active energy ray curable polymer (A) or the active energy ray non-curable polymer and the crosslinking agent may be advanced to form a crosslinked structure at a desired density in the pressure-sensitive adhesive layer. After laminating the pressure-sensitive adhesive layer on the substrate by the above-mentioned method or the like in order to allow the crosslinking reaction to proceed sufficiently, the obtained work processing sheet is, for example, several days in an environment of 23 ° C. and 50% relative humidity. You may do the curing such as leaving still.

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

4. Method of using a sheet for processing a work The sheet for processing a work according to the present embodiment can be used for processing a work. That is, after the adhesive surface of the work processing sheet according to the present embodiment is attached to the work, the work can be processed on the work processing sheet. According to the said process, the sheet | seat for work processing which concerns on this embodiment can be used as a back grind sheet, a dicing sheet, an expand sheet, a pickup sheet etc. Here, examples of the workpiece include a semiconductor wafer, a semiconductor member such as a semiconductor package, and a glass member such as a glass plate.

Moreover, when the sheet | seat for workpiece processing which concerns on this embodiment is equipped with the adhesive bond layer mentioned above, the said sheet | seat for workpiece processing can be used as a dicing die bonding sheet. Furthermore, when the work processing sheet according to the present embodiment includes the above-described protective film forming layer, the work processing sheet can be used as a protective film formation and dicing sheet.

In the work processing sheet according to the present embodiment, the oxygen atom ratio R ₁₀₀ measured by X-ray photoelectron spectroscopy at a position 100 nm deep from the adhesive surface among the positions in the pressure-sensitive adhesive layer is in the above-mentioned range. Even when the pressure-sensitive adhesive that constitutes the pressure-sensitive adhesive layer adheres to the work after processing, the pressure-sensitive adhesive can be favorably removed by flowing water. Furthermore, when the oxygen atom ratio _R0 measured by X-ray photoelectron spectroscopy on the adhesive surface is in the above-mentioned range, the work after processing can be easily separated. Therefore, it is preferable to use the sheet for processing a work according to the present embodiment in processing in which flowing water is used, and in particular, it is preferable to use it for dicing involving supplying flowing water to the cut portion is there. That is, the work processing sheet according to the present embodiment is preferably used as a dicing sheet.

When using the sheet | seat for work processing which concerns on this embodiment as a dicing sheet | seat, general conditions can be used as the conditions of dicing and the supply conditions of flowing water. Particularly with regard to the supply conditions of running water, it is preferable to use pure water or the like as the water used. The amount of water supplied is preferably 0.5 L / min or more, and more preferably 1 L / min or more. The amount of water supplied is preferably 2.5 L / min or less, and more preferably 2 L / min or less. In addition, the temperature of water is not specifically limited, For example, it is preferable to set it as about room temperature.

[Method of manufacturing processed work]
In the method of manufacturing a processed work according to an embodiment of the present invention, a bonding step of bonding a work to the surface of the pressure-sensitive adhesive layer of the work processing sheet described above opposite to the base, and work processing The processing step of obtaining the processed work stacked on the work processing sheet by processing the work on the work sheet, and irradiating the pressure-sensitive adhesive layer with an active energy ray to cure the pressure-sensitive adhesive layer And an irradiation step of reducing the adhesion of the work processing sheet to the processed work, and a separation step of separating the processed work from the work processing sheet after the active energy ray irradiation.

In the work processing sheet used in the method for producing a processed work of this embodiment, even when the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer adheres to the work after processing, the pressure-sensitive adhesive is favorably used by flowing water. It can be removed and the processed work can be easily separated. Therefore, according to the method of manufacturing a processed work of the present embodiment, it is possible to efficiently manufacture the processed work.

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

(1) Bonding process The bonding of the work and the work processing sheet in the bonding process can be performed by a conventionally known method. In addition, when performing dicing of a work in the subsequent processing step, it is preferable to bond a ring frame to the area on the outer peripheral side of the area to which the work is to be bonded on the adhesive layer side of the work processing sheet. . Moreover, 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) Processing Step In the processing step, desired processing can be performed on the workpiece, and for example, back grinding, dicing, etc. can be performed. These processes can be performed by a conventionally known method.

In addition, when performing blade dicing using a rotating blade as the above-mentioned processing, in general, a part of the pressure-sensitive adhesive layer in the work processing sheet is cut together with the work. At this time, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer may be wound up by a blade and attached to the processed work. However, in the work processing sheet used in the method of manufacturing a processed work of the present embodiment, as described above, the adhered pressure sensitive adhesive can be removed well by flowing water. From this point of view, the processing in the present embodiment is preferably dicing, and particularly preferably blade dicing using a rotating blade.

(3) Irradiation process In the irradiation process, as long as the adhesion of the work processing sheet to the processed work can be reduced to a desired degree, the conditions for irradiation of the active energy ray are not limited, and based on the conventionally known methods. It can be carried out. Examples of the type of active energy ray to be used include ionizing radiation, that is, X-rays, ultraviolet rays, electron beams, etc. Among them, ultraviolet rays which are relatively easy to introduce irradiation equipment are preferable.

(4) Separation step In the separation step, separation is performed according to the type of processing and the obtained processed workpiece. For example, when dicing is performed as processing and a chip in which the work is separated is obtained by the dicing, the obtained chips are individually obtained from the work processing sheet using a conventionally known pickup device. Pick up. Moreover, in order to make the said pickup easy, the sheet | seat for workpiece processing may be expanded, and you may space apart processed workpieces.

(5) Others In the method of manufacturing a processed work of the present embodiment, steps other than the above-described steps may be provided. For example, after the bonding step, there may be provided a transport step of transporting the laminate of the obtained work and the work processing sheet to a predetermined position, or a storage step of storing the laminate for a predetermined period. In addition, after the separation step, a mounting step or the like may be provided in which the obtained processed workpiece is mounted on a predetermined base or the like.

The embodiments described above are described to facilitate the 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 substrate and the pressure-sensitive adhesive layer, or on the surface of the substrate opposite to the pressure-sensitive adhesive layer.

Hereinafter, the present invention will be more specifically described by way of 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 adhesive composition 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 The coalescence is reacted with 21.4 g (corresponding to 80 mol% based on the number of moles of 2-hydroxyethyl acrylate) of methacryloyloxyethyl isocyanate (MOI) with respect to 100 g of the acrylic copolymer. An active energy ray-curable polymer was obtained. It was 600,000 when the weight average molecular weight (Mw) of this active energy ray curable polymer was measured by the method mentioned later.

100 parts by mass of the obtained active energy ray-curable polymer (in terms of solid content, hereinafter the same) and 3 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name “IRGACURE 184”) as a photopolymerization initiator And 9.32 parts by mass of toluene diisocyanate (made by Tosoh Corp., product name "Coronato L") as a crosslinking agent, and an 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 was mixed in a solvent to obtain an adhesive composition.

(2) Formation of Pressure-Sensitive Adhesive Layer With respect to the release surface of a release sheet (Lintec Co., Ltd., product name “SP-PET 381031”) in which a silicone release agent layer is formed on one side of a 38 μm thick polyethylene terephthalate film. The above-mentioned pressure-sensitive adhesive composition was applied, dried by heating, and then aged under conditions of 23 ° C. and 50% RH for 7 days to form a 5 μm-thick pressure-sensitive adhesive layer on the release sheet.

(3) Preparation of Workpiece Processing Sheet The surface of the pressure-sensitive adhesive layer formed in the above step (2) opposite to the release sheet, and a 80 μm-thick ethylene-methacrylic acid copolymer (EMAA) film as a substrate The sheet | seat for workpiece processing was obtained by bonding together to one side of.

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

Example 2 and Comparative Examples 1 to 3
A work processing sheet was produced 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 work processing sheet manufactured in the examples and comparative examples, and the oxygen atom ratio (%) in the exposed surface (adhesive surface) of the exposed pressure-sensitive adhesive layer and the adhesion at a depth of 100 nm from the exposed surface The oxygen atom ratio (%) in the agent layer was measured using an X-ray photoelectron spectrometer (manufactured by ULVAC-PHI, product name “PHI Quantera SXM”), and the oxygen atom ratio at “0 nm position” ( % And the oxygen atomic ratio (%) at the position of 100 nm. The results are shown in Table 1.

[Test Example 2] (Measurement of Adhesive Strength)
By peeling the release sheet from the work processing sheet manufactured in the example and the comparative example, overlapping the exposed surface of the exposed adhesive layer on the mirror surface of the mirror-finished 6-inch silicon wafer, and reciprocating a 2 kg roller one time A load was applied for bonding and left for 20 minutes to obtain a sample for measuring the adhesive strength.

About the sample for adhesive force measurement, the sheet for work processing is peeled off from the silicon wafer at a peeling speed of 300 mm / min and a peeling angle of 180 °, and adhesion to the silicon wafer is carried out by the 180 ° peeling method according to JIS Z0237: 2009. The force (mN / 25 mm) was measured. The results are shown in Table 1 as adhesion before UV irradiation (before UV).

[Test Example 3] (Evaluation of removability of adhesive)
The release sheet was peeled off from the work processing sheet manufactured in Examples and Comparative Examples, and the exposed surface of the exposed adhesive layer was exposed using a tape mounter (manufactured by Lintec Corporation, product name "Adwill RAD 2500 m / 12") A polished surface of 2000 polished 6 inch silicon wafer (thickness: 150 μm) was attached. Subsequently, using a dicing apparatus (manufactured by Disco, product name “DFD-6361”), dicing was performed from the 6-inch silicon wafer side while supplying flowing water to the cutting portion under the following dicing conditions.

<Dicing conditions>
・ Dicing device: made by DISCO DFD-6361
・ Blade: Disco made NBC-2H 2050 27HECC
・ Blade width: 0.025 to 0.030 mm
-Cutting edge amount: 0.640 to 0.760 mm
-Blade rotation speed: 50000 rpm
・ Cutting speed: 20 mm / sec
· Depth of cut: 15 μm from the surface on the adhesive layer side of the work processing sheet
・ Flow water supply amount: 1.0 L / min
・ Flowing water temperature: Room temperature ・ Cut size: 10 mm × 10 mm

Twenty chips obtained by the above dicing were separated from the work processing sheet, and it was visually confirmed whether or not the adhesive adhered to them. And the removability of the adhesive was evaluated based on the following references | standards. The results are shown in Table 1.
:: There were 0 chips adhering to the adhesive.
X: One or more chips to which the adhesive was attached.

[Test Example 4] (Evaluation of Separability)
Dicing was performed in the same manner as in Test Example 3 using the work processing sheets manufactured in the examples and the comparative examples. After completion of dicing, the surface on the side of the work processing sheet is irradiated with ultraviolet (UV) light using an ultraviolet irradiation device (manufactured by LINTEC Corporation, product name “RAD-2000”) (illuminance: 230 mW / cm ² , light amount: 190 mJ / cm ² ), the adhesive layer was cured. Thereafter, all the obtained chips were picked up from the work processing sheet. At this time, the workpiece processing sheet was pushed up with a needle from the surface opposite to the surface to which the glass chip was attached (the number of needles: 4, the pushing speed: 50 mm / sec, the pushing height: 0.5 mm) ). Based on the condition of the pickup at this time, the separability at the time of separating the chip from the work processing sheet was evaluated according to the following criteria. The results are shown in Table 1.
○: I was able to pick up without any problems.
X: It was not possible to pick up well because the chips could not be separated or the chips were broken.

The details of the abbreviations and the like described in Table 1 are as follows.
BA: butyl acrylate MMA: methyl methacrylate MA: methyl acrylate 2 MEA: 2-methoxyethyl acrylate HEA: 2-hydroxyethyl acrylate

As can be seen from Table 1, according to the work processing sheet obtained in the example, it was possible to remove the adhesive favorably by the flowing water, and it was possible to separate the work after processing well. .

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

Claims (6)

1. A work processing sheet comprising: a base material; and an adhesive layer laminated on one side of the base material,
   The pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive,
   The oxygen atom ratio R ₀ measured by X-ray photoelectron spectroscopy on the surface of the pressure-sensitive adhesive layer opposite to the substrate is 28 atomic% or less.
   The oxygen atom ratio R ₁₀₀ measured by X-ray photoelectron spectroscopy at a position 100 nm deep from the surface opposite to the substrate in the pressure-sensitive adhesive layer among the positions in the pressure-sensitive adhesive layer is 20 atomic% or more And 29 atomic% or less.
2. The value of the oxygen atom ratio R ₀ is larger than the value of the oxygen atom ratio R ₁₀₀ ,
   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 (1)
   The reduction rate of the oxygen atom ratio calculated from the above is 0% or more and 15% or less, The work processing sheet according to claim 1.
3. The work processing sheet according to claim 1 or 2, wherein 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. .
4. The pressure-sensitive adhesive composition is 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. Containing
   The acrylic copolymer is selected from methyl acrylate, 2-methoxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate and methoxy ethylene glycol (meth) acrylate as monomer units constituting the polymer. The work processing sheet according to any one of claims 1 to 3, comprising at least one selected from the group consisting of
5. The work processing sheet according to any one of claims 1 to 4, which is a dicing sheet.
6. A bonding step of bonding a work with a surface of the pressure-sensitive adhesive layer of the work processing sheet according to any one of claims 1 to 5 on the opposite side to the substrate,
   A processing step of obtaining a processed work laminated on the work processing sheet by processing the work on the work processing sheet;
   An irradiation step of irradiating the pressure-sensitive adhesive layer with an active energy ray to cure the pressure-sensitive adhesive layer and reducing the adhesion of the work processing sheet to the processed work;
   A method of manufacturing a processed work comprising: separating the processed work from the sheet for processing a work after irradiation of active energy rays.