WO2020053981A1 - Work processing sheet and method of manufacturing processed work - Google Patents

Abstract

A work processing sheet provided with a base material and an adhesive agent layer, wherein: the adhesive agent layer is composed of an active energy ray-curable adhesive agent; the water contact angle on a surface of the adhesive agent layer on the side opposite to the base material is more than 80°; the adhesive force of the work processing sheet with respect to a silicon wafer is not more than 5000 mN/25 mm; and, when a non-woven cloth soaked with methyl ethyl ketone is placed over the surface of the adhesive agent layer on the side opposite to the base material, and, after being left to stand in an environment of 23°C with a relative humidity of 50% for 15 minutes, the surface is wiped with the non-woven cloth and dried by being left to stand in an environment of 23°C with a relative humidity of 50% for one hour, the water contact angle measured on the surface is not less than 50° and not more than 80°. With the work processing sheet, it is possible to well remove, with running water, adhesive agent deriving from the adhesive agent layer that has become attached to the work after processing, and to well separate the work after processing.

Description

Work processing sheet and method of manufacturing 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 manufactured in small element pieces (hereinafter, referred to as “elements”). After being cut (diced) and separated (picked up) individually, the chip is transferred to the next step, a mounting step. At this time, an object to be cut such as a semiconductor wafer is subjected to dicing, washing, drying, expanding, pickup, and mounting steps in a state of being adhered to a work processing sheet having a base material and an adhesive layer. You.

In the above-mentioned dicing step, the dicing blade, the object to be cut and the sheet for processing the work are heated by frictional heat generated between the rotating dicing blade and the object to be cut and the sheet for processing the work. Further, in the dicing step, cut pieces may be generated from the workpiece or the work processing sheet, and may adhere to the chip.

Therefore, when performing the dicing step, usually, running water is supplied to the cut portion to cool the dicing blade and the like, and to remove generated cuttings from the chip.

Patent Document 1 discloses that the contact angle of pure water on the surface of the pressure-sensitive adhesive layer opposite to the substrate before irradiation with pure water is 82 ° to 114 ° in order to promote the removal of cutting pieces by such running water. A work processing sheet is disclosed which has a contact angle with methylene iodide 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. .

Patent No. 5019657

However, when the dicing process is performed 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 processed work. I couldn't.

Generally, when a chip is separated from a work processing sheet in a pick-up process, it is required that the chip can be separated without requiring excessive force, so that defects such as breakage of the chip do not occur. .

The present invention has been made in view of such a situation, and the pressure-sensitive adhesive derived from the pressure-sensitive adhesive layer attached to the processed work can be satisfactorily removed by running water, and the processed work can be removed. It is an object of the present invention to provide a work processing sheet that can be satisfactorily 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 work processing sheet including a base material and an adhesive layer laminated on one surface side of the base material, wherein the adhesive layer has an active layer. An energy ray-curable pressure-sensitive adhesive, the water contact angle of the surface of the pressure-sensitive adhesive layer opposite to the substrate is more than 80 °, and the adhesive force of the work processing sheet to the silicon wafer is reduced. 5000 mN / 25 mm or less, a non-woven fabric impregnated with methyl ethyl ketone is laminated on the surface of the pressure-sensitive adhesive layer opposite to the substrate, and left standing for 15 minutes in an environment of 23 ° C. and 50% relative humidity. After that, the surface was wiped off with the nonwoven fabric, and allowed to stand for 1 hour in an environment of 23 ° C. and a relative humidity of 50%. ° or less That provides a work processing sheet (invention 1).

In the work processing sheet according to the above invention (Invention 1), the water contact angle of the surface of the pressure-sensitive adhesive layer opposite to the substrate (hereinafter, may be referred to as a “pressure-sensitive surface”) before the wiping described above is in the above range. By virtue of this, the adhesive surface has an appropriate hydrophobicity, and the work after processing can be easily separated satisfactorily. Further, the adhesive force of the work processing sheet to the silicon wafer is within the above range, and the water contact angle after wiping is within the above range, so that the adhesive force of the adhesive adhered to the processed work is water. , And the pressure-sensitive adhesive adhered to the work after processing can be satisfactorily removed by running water.

In the above invention (Invention 1), the active energy ray-curable adhesive is preferably an adhesive formed from an adhesive composition containing an active energy ray-polymerizable branched polymer (Invention 2).

In the above inventions (Inventions 1 and 2), the pressure-sensitive adhesive composition is 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 methyl acrylate, 2-methoxyethyl (meth) acrylate, and (meth) as monomer units constituting the polymer. ) It is preferable to include at least one selected from ethyl carbitol acrylate and methoxyethylene glycol (meth) acrylate (Invention 3).

に お い て In the above inventions (Inventions 1 to 3), a dicing sheet is preferable (Invention 4).

Secondly, the present invention provides a laminating step of laminating a surface of the pressure-sensitive adhesive layer of the work processing sheet (Invention 1 to 4) opposite to the base material with a work; Processing the work on the sheet, a processing step of obtaining a processed work laminated on the work processing sheet, and irradiating the adhesive layer with active energy rays, the adhesive layer Curing, 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 active energy ray irradiation. The present invention provides a method for producing a processed workpiece characterized by the following (Invention 5).

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

Hereinafter, embodiments of the present invention will be described.
[Work processing sheet]
The work processing sheet 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 Work Processing Sheet In the work processing sheet according to the present embodiment, the water contact angle of the surface (adhesive surface) of the pressure-sensitive adhesive layer opposite to the substrate is greater than 80 °. When the water contact angle is in the above range, the adhesive surface has appropriate hydrophobicity, and an excessive increase in the adhesive force to the workpiece after processing the workpiece processing sheet is suppressed. 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 workpiece, there are many relatively hydrophilic groups on the surface of the silicon wafer, and an adhesive surface having a moderate hydrophobicity comes into contact with this surface. Thereby, the work after processing can be easily separated. The details of the method for measuring the water contact angle described above are as described in Test Examples described later.

In this specification, as described later, the water contact angle of the adhesive surface after performing wiping with a rag containing methyl ethyl ketone is also specified, but without referring to such wiping, `` When the phrase "water contact angle" is used, the phrase shall mean the water contact angle measured without performing the wiping described above. Further, the pressure-sensitive adhesive layer in the present embodiment is composed of an active energy ray-curable pressure-sensitive adhesive, but the water contact angle in the present specification is any of before and after the wiping described above. In the case of, the water contact angle measured without irradiating the work processing sheet with active energy rays is also used.

と When the water contact angle is 80 ° or less, the adhesive surface has relatively high hydrophilicity, and the adhesive force to the workpiece after processing the workpiece processing sheet becomes excessively high. In this case, an excessive force is required when the work after processing is separated from the work processing sheet, and there is a possibility that a problem such as breakage of the work after processing may occur. In this respect, the water contact angle is preferably equal to or greater than 85 °, and particularly preferably equal to or greater than 90 °.

The water contact angle is preferably 120 ° or less, particularly preferably 110 ° or less. When the water contact angle is 120 ° or less, the adhesive surface is prevented from having excessive hydrophobicity, and the work processing sheet easily exerts good adhesive force on the work. This has the effect that the work before or after processing is unintentionally peeled off from the work processing sheet when the work is processed or when the work or the processed work is transported in a stacked state on the work processing sheet. Is suppressed.

In the sheet for processing a work according to the present embodiment, a nonwoven fabric containing methyl ethyl ketone is laminated on the adhesive surface, and left standing for 15 minutes in an environment of 23 ° C. and a relative humidity of 50%. The water contact angle measured on the adhesive surface dried by wiping the surface and allowing to stand for 1 hour in an environment of 23 ° C. and 50% relative humidity is 50 ° or more and 80 ° or less. Since the water contact angle after wiping the surface of the adhesive surface as described above is within the above range, the adhesive derived from the adhesive layer adhered to the work after processing can be favorably removed by running water. Becomes

As described above, the reason that the water contact angle after wiping the adhesive surface is 50 ° or more and 80 ° or less, and the reason why the adhesive adhered to the processed work can be easily removed by running water is limited thereto. Although not necessarily, the following can be considered. By performing the wiping described above, it is considered that a predetermined component on the surface of the adhesive surface is removed, or the adhesive constituting the adhesive layer by a predetermined thickness is removed from the surface. As a result, the part that originally constituted the inside of the pressure-sensitive adhesive layer is exposed on the surface. In the work processing sheet according to the present embodiment, the water contact angle of the exposed surface is 50 ° or more and 80 ° or less. On the other hand, when the work is processed on the work processing sheet, and the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer adheres to the work after processing as a cutting piece, the pressure-sensitive adhesive adheres to the work after processing. The surface that comes into contact with the surface of the pressure-sensitive adhesive layer is more stochastically the surface that forms the inside of the pressure-sensitive adhesive layer than the surface that forms the surface of the pressure-sensitive adhesive layer. That is, in most cases, a surface having a water contact angle of 50 ° or more and 80 ° or less comes into contact with the processed work in the adhesive adhered to the processed work. And, since the surface having such a water contact angle shows a suitable affinity for water, by using flowing water, the above-mentioned pressure-sensitive adhesive is favorably removed from the processed work. Becomes possible.

If the water contact angle after wiping as described above is less than 50 °, the pressure-sensitive adhesive layer will exhibit an excessive affinity for water, and it will not be possible to suppress water intrusion. Occasionally, chip fly or chip breakage occurs. When the water contact angle exceeds 80 °, the pressure-sensitive adhesive as a cut piece does not have an appropriate affinity for water, and the pressure-sensitive adhesive adhered to the processed workpiece is sufficiently removed by running water. It will be difficult to do.

From the viewpoints described above, the water contact angle after the wiping described above is preferably 55 ° or more, and particularly preferably 60 ° or more. The water contact angle after the wiping described above is preferably 75 ° or less, particularly preferably 70 ° or less. The details of the method of measuring the water contact angle after the wiping described above are as described in Test Examples described later.

で は In the work processing sheet according to the present embodiment, the adhesive force of the work processing sheet to the silicon wafer is 5000 mN / 25 mm or less. Here, the adhesive strength refers to the adhesive strength in a state where the work processing sheet is not irradiated with the active energy ray and the pressure-sensitive adhesive layer is not cured. In addition, throughout the present specification, the "adhesive force" described without mentioning the presence or absence of the irradiation of the active energy ray, the work processing sheet was not irradiated with the active energy ray, the pressure-sensitive adhesive layer Refers to the adhesive strength in a state where no curing has occurred. The details of the method for measuring the adhesive force of the work processing sheet to the silicon wafer are as described in Test Examples described later.

When the adhesive force of the work processing sheet to the silicon wafer is 5000 mN / 25 mm or less, the adhesive force of the adhesive adhered as a cutting piece to the work after processing does not become excessively high. The agent can be easily removed by running water. On the other hand, when the adhesive force of the work processing sheet to the silicon wafer exceeds 5000 mN / 25 mm, the adhesive is firmly adhered to the work after processing as a cutting piece, and even if running water is used, the adhesive is not sufficiently applied. It is difficult to remove the ash. From this viewpoint, the adhesive force of the work processing sheet to the silicon wafer is preferably 4500 mN / 25 mm or less, and particularly preferably 3000 mN / 25 mm or less.

粘着 Further, the adhesive force 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. When the adhesive force of the work processing sheet to the silicon wafer is 1000 mN / 25 mm or more, the work to be processed can be satisfactorily held on the work processing sheet. When the subsequent work is conveyed in a state of being stacked on the work processing sheet, the peeling of the work before or after the processing can be favorably suppressed. In particular, when the work after processing is a chip, it is possible to favorably suppress the chip from scattering from the work processing sheet.

In the work processing sheet according to the present embodiment, it is preferable that the work processing sheet has an adhesive force to the silicon wafer of 65 mN / 25 mm or less after irradiating the work processing sheet with the active energy ray. When the adhesive force 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 work processing is completed. Become.

2. Components of Work Processing Sheet (1) Substrate In the work processing sheet according to the present embodiment, the base material exhibits a desired function in a process of using the work processing sheet, and preferably cures the pressure-sensitive adhesive layer. There is no particular limitation as long as it exhibits good permeability to active energy rays irradiated for the purpose.

For example, the base material is preferably a resin film mainly composed of a resin material, and specific examples thereof include an ethylene-vinyl acetate copolymer film; an ethylene- (meth) acrylic acid copolymer film, Ethylene copolymer films such as ethylene-methyl (meth) acrylate copolymer film and other ethylene- (meth) acrylate copolymer films; polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene Polyolefin films such as films, ethylene-norbornene copolymer films and norbornene resin films; polyvinyl chloride films such as polyvinyl chloride films and vinyl chloride copolymer films; polyethylene terephthalate films, polybutylene tele (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 the polyethylene film include a low density polyethylene (LDPE) film, a linear low density polyethylene (LLDPE) film, a high density polyethylene (HDPE) film, and the like. Further, modified films such as crosslinked films and ionomer films are also used. Further, the substrate may be a laminated film in which a plurality of the above-described films are laminated. In this laminated film, the materials constituting each layer may be the same or different. 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 base material may contain various additives such as a flame retardant, a plasticizer, an antistatic agent, a lubricant, an antioxidant, a colorant, an infrared absorber, an ultraviolet absorber, and an ion scavenger. The content of these additives is not particularly limited, but is preferably in a range where the base material exhibits a desired function.

(4) The surface of the base material on which the pressure-sensitive adhesive layer is laminated may be subjected to a surface treatment such as a primer treatment, a corona treatment, and a plasma treatment in order to increase the adhesion to the pressure-sensitive adhesive layer.

(4) The thickness of the base material can be appropriately set according to the method in which the work processing sheet is used, but is usually preferably 20 μm or more, and particularly preferably 25 μm or more. In addition, the thickness is usually preferably 450 μm or less, and particularly preferably 300 μm or less.

(2) Pressure-sensitive adhesive layer In the sheet for processing a work according to the present embodiment, the pressure-sensitive adhesive layer is formed of an active energy ray-curable pressure-sensitive adhesive, and can achieve the above-mentioned pressure-sensitive adhesive strength. There is no particular limitation as long as a water contact angle before and after wiping can be achieved.

In the work processing sheet according to the present embodiment, since the pressure-sensitive adhesive layer is formed of an active energy ray-curable pressure-sensitive adhesive, the processed work and the pressure-sensitive adhesive surface adhered to the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer. When separating the sheet, the pressure-sensitive adhesive layer is cured by irradiating active energy rays to reduce the adhesive force of the work sheet to the work after processing. This facilitates separation of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer from the processed work.

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

First, the case where the pressure-sensitive adhesive layer in this embodiment is formed from 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) acrylate (co) polymer (A) (hereinafter, referred to as a (meth) acrylate) having a functional group (active energy ray-curable group) having an active energy ray-curable side chain introduced therein. "Active energy ray-curable polymer (A)"). This 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 bonded to the functional group. It is preferably obtained by reacting.

The acrylic copolymer (a1) may be, as a monomer unit constituting the polymer, a monomer for adjusting the hydrophilicity of the acrylic copolymer (a1) (hereinafter, may be referred to as a “hydrophilicity adjusting monomer”). ), And specific examples thereof include methyl acrylate, 2-methoxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate (ethoxyethoxyethyl (meth) acrylate) and (meth). ) It is preferable to include at least one selected from methoxyethylene glycol acrylate. These monomers can improve the hydrophilicity of the acrylic copolymer (a1), whereby the water contact angle and the adhesive strength before and after the wiping described above in the formed pressure-sensitive adhesive layer are in the ranges described above, respectively. It becomes easy to adjust. From the viewpoint that such an effect can be easily obtained, the acrylic copolymer (a1) includes, as monomer units constituting the polymer, methyl acrylate, 2-methoxyethyl acrylate and methoxy acrylate among the above-mentioned monomers. It is preferable to include at least one kind of ethylene glycol.

When the acrylic copolymer (a1) contains methyl acrylate as a monomer unit constituting the polymer, the content of methyl acrylate is preferably at least 10% by mass, particularly preferably at least 20% by mass. , And more preferably 30% by mass or more. Further, the content of methyl acrylate is preferably 85% by mass or less. With these contents, in the formed pressure-sensitive adhesive layer, the water contact angle and the adhesive force before and after the wiping described above can be easily adjusted respectively in the above-described ranges. In the present specification, the content (% by mass) of methyl acrylate described above means the content based on all the monomers constituting the acrylic copolymer (a1). Further, the content (% by mass) of the other monomers described below means the content based on all the monomers constituting the acrylic copolymer (a1).

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, In particular, it is preferably at least 20% by mass, and more preferably at least 30% by mass. 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 formed pressure-sensitive adhesive layer, the water contact angle and the adhesive force before and after the wiping described above can be easily adjusted respectively in the above-described ranges.

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 reduced. 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. Further, the total value is preferably 90% by mass or less, particularly preferably 85% by mass or less. When the total value is within these ranges, it is easy to adjust the water contact angle and the adhesive force before and after the wiping described above in the above-described ranges, respectively, 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, and particularly preferably 30% by mass or more. It is preferable that the amount is at least mass%. Further, the content of methoxyethylene glycol acrylate is preferably 85% by mass or less, particularly preferably 80% by mass or less. With these contents, in the formed pressure-sensitive adhesive layer, the water contact angle and the adhesive force before and after the wiping described above can be easily adjusted respectively in the above-described ranges.

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

The functional group-containing monomer as a constituent unit of the acrylic copolymer (a1) has a polymerizable double bond and a functional group such as a hydroxy group, a carboxy group, an amino group, a substituted amino group, and an epoxy group in a molecule. And among them, 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 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 and 4-hydroxybutyl (meth) acrylate, which may be used alone or in combination of two or more.

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

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

The acrylic copolymer (a1) preferably contains 1% by mass or more, more preferably 5% by mass or more, and further preferably 10% by mass or more of a structural unit derived from the functional group-containing monomer. Is preferred. Further, the acrylic copolymer (a1) preferably contains the structural unit derived from the functional group-containing monomer in an amount of 35% by mass or less, particularly preferably 30% by mass or less.

Examples of the (meth) acrylic acid ester monomer constituting the acrylic copolymer (a1) include, in addition to (meth) acrylic acid alkyl esters having an alkyl group having 1 to 20 carbon atoms, for example, an alicyclic compound in the molecule. A monomer having a structure (an alicyclic structure-containing monomer) is preferably used.

As the alkyl (meth) acrylate, alkyl (meth) acrylates having 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. These may be used alone or in combination of two or more.

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 dicyclopentenyloxyethyl (meth) acrylate are preferably used. These may be used alone or in combination of two or more.

Further, the acrylic copolymer (a1) preferably contains 50% by mass or more, and particularly preferably 60% by mass or more, of a structural unit derived from a (meth) acrylate monomer or a derivative thereof. Further, the content is preferably 70% by mass or more. Further, the acrylic copolymer (a1) preferably contains 99% by mass or less, and particularly preferably 95% by mass or less, of a structural unit derived from a (meth) acrylate monomer or a derivative thereof. Preferably, the content is more preferably 90% by mass or less.

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

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

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

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

The unsaturated group-containing compound (a2) is preferably at least 50 mol%, particularly preferably at least 60 mol%, more preferably at least 50 mol%, based on the number of moles of the functional group-containing monomer of the acrylic copolymer (a1). It is used in a proportion of 70 mol% or more. The unsaturated group-containing compound (a2) is preferably at most 95 mol%, particularly preferably at most 93 mol%, 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 between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2), the reaction between the functional group of the acrylic copolymer (a1) and the functional group of the unsaturated group-containing compound (a2) is performed. 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) reacts with the functional group in the unsaturated group-containing compound (a2), and the unsaturated group in the acrylic copolymer (a1) The active energy ray-curable polymer (A) which is introduced into the side chain is obtained.

The weight average molecular weight (Mw) of the active energy ray-curable polymer (A) thus obtained is preferably at least 10,000, particularly preferably at least 150,000, and more preferably at least 200,000. Preferably it is. Further, the weight average molecular weight (Mw) is preferably 1.5 million or less, particularly preferably 1,000,000 or less. The weight average molecular weight (Mw) in the present specification is a value in terms of standard polystyrene measured by gel permeation chromatography (GPC).

Even when the pressure-sensitive adhesive composition according to 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. (B) may further be contained.

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 an active energy ray-curable monomer and / or oligomer (B) include monofunctional acrylates 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 Polyfunctional acrylates such as glycol di (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, polyester oligo (meth) acrylate, polyurethane oligo ( Data) acrylate, and the like.

When an active energy ray-curable monomer and / or oligomer (B) is blended together with the active energy ray-curable polymer (A), the active energy ray-curable monomer and / or oligomer (B ) Is preferably more than 0 parts by mass, particularly preferably 60 parts by mass or more, based on 100 parts by mass of the active energy ray-curable polymer (A). Further, the content is preferably 250 parts by mass or less, and particularly preferably 200 parts by mass or less, based on 100 parts by mass of the active energy ray-curable polymer (A).

Here, when ultraviolet rays are used as active energy rays for curing the active energy ray-curable pressure-sensitive adhesive, the pressure-sensitive adhesive composition according to the present embodiment preferably contains a photopolymerization initiator (C). By using the photopolymerization initiator (C), the polymerization curing time and the amount of light irradiation can be reduced.

Specific examples of the photopolymerization initiator (C) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, methyl benzoin benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, tetramethyl thiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4 6-trimethylbenzyldiphenyl) 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 determined based on the amount of the active energy ray-curable polymer (A) (when the active energy ray-curable monomer and / or oligomer (B) is blended, It is preferably 0.1 part by mass or more based on 100 parts by mass of the active energy ray-curable polymer (A) and the active energy ray-curable monomer and / or oligomer (B) (100 parts by mass in total). In particular, it is preferably at least 0.5 part by mass. In addition, the content 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 (A) The amount is preferably 10 parts by mass or less, particularly preferably 6 parts by mass or less, based on 100 parts by mass of the active energy ray-curable monomer and / or oligomer (B) (100 parts by mass in total).

粘着 The pressure-sensitive adhesive composition of the present embodiment preferably contains an additive (D) for adjusting the water contact angle on the surface of the pressure-sensitive adhesive layer. Examples of such additives include an active energy ray-polymerizable branched polymer, a branched polymer, and an epoxy resin. Among them, the water contact angle on the surface of the pressure-sensitive adhesive layer is adjusted to the above-described range. From the viewpoint of easiness, 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. Since the pressure-sensitive adhesive layer in this embodiment is formed from the pressure-sensitive adhesive composition containing the active energy ray-polymerizable branched polymer, the water contact angle on the surface of the pressure-sensitive adhesive layer (the water contact angle before wiping described above). ) Is more than 80 °, and the water contact angle after the wiping is set to 50 ° or more and 80 ° or less. The reason for this is not limited thereto, but may be as follows. 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 closer to the surface as compared to the inside, the more the content of the active energy ray-polymerizable branched polymer is present. Here, since the active energy ray polymerizable branched polymer itself is a component having a high tendency to be hydrophobic, the surface of the pressure-sensitive adhesive layer in which the active energy ray polymerizable branched polymer is more present has a water contact of more than 80 °. The corner can be easily achieved. On the other hand, after the active energy ray-polymerizable branched polymer present on the surface is removed by the above-described wiping, a water contact angle of 50 ° or more and 80 ° or less can be easily achieved. As described above, it is easy to achieve different water contact angles before and after wiping.

Further, since the pressure-sensitive adhesive layer in the present embodiment is formed from the pressure-sensitive adhesive composition containing the active energy ray-polymerizable branched polymer, the surface of the pressure-sensitive adhesive layer becomes relatively hydrophobic, Thereby, the adhesive force of the work processing sheet to the silicon wafer can be easily adjusted to the above-described range, and the processed work can be easily separated from the work processing sheet. 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 polymer is not active or active. A polymerization reaction can occur between the energy beam polymerizable branched polymer and the component having an active energy beam curable group, thereby suppressing migration of the active energy beam polymerizable branched polymer to a work after processing. At the same time, the pressure-sensitive adhesive layer after the irradiation with the active energy rays becomes more 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, the active energy contained 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 for obtaining such an active energy ray polymerizable branched polymer, for example, a monomer having two or more radical polymerizable double bonds in a molecule, an active hydrogen group and one radical polymerizable double bond are used. Having a branched structure, which is obtained by polymerizing a monomer having the following formula in the molecule and a monomer having one radical polymerizable double bond in the molecule, reacts 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 above-mentioned three types of monomers may be (meth) acrylic acid esters or (meth) acrylic acid, respectively. In this case, the active energy ray-polymerizable branched polymer is an acrylic polymer.

重量 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-described range, the water contact angle on the surface of the pressure-sensitive adhesive layer can be easily adjusted to the above-described range.

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). , The total amount of the active energy ray-curable polymer (A) and the active energy ray-curable monomer and / or oligomer (B) is 100 parts by mass), and is preferably 0.05 part by mass or more. It is preferably at least 0.1 part by mass. Further, 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 (A) (A) and 100 parts by mass of the active energy ray-curable monomer and / or oligomer (B)), preferably 1 part by mass or less, particularly preferably 0.5 part by mass or less. . When the content of the additive (D) is in the above-described range, the water contact angle on the surface of the pressure-sensitive adhesive layer can be easily adjusted to the above-described range.

粘着 The pressure-sensitive adhesive composition according to the present embodiment may optionally contain other components in addition to the components described 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 polyacrylates, polyesters, polyurethanes, polycarbonates, polyolefins, etc., and polymers or polymers having a weight average molecular weight (Mw) of 3,000 to 2,500,000. Oligomers are preferred. By blending the component (E) with the active energy ray-curable pressure-sensitive adhesive, the tackiness and peelability before curing, the strength after curing, the adhesion to other layers, the storage stability, and the like can be improved. The 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 based on 100 parts by mass of the active energy ray-curable polymer (A).

多 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 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 resins and the like can be mentioned.

配合 The compounding amount of the crosslinking agent (F) is preferably at least 0.01 part by mass, more preferably at least 3 parts by mass, based on 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 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 or more active energy ray-curable groups. In the following, a description will be given of a case in which the information is obtained.

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

モ ノ マ ー As the monomer and / or oligomer having at least one or more active energy ray-curable groups, the same as the above-mentioned component (B) can be selected. The compounding 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 at least 1 with respect to 100 parts by mass of the active energy ray non-curable polymer component. The amount of the monomer and / or oligomer having two or more active energy ray-curable groups is preferably 1 part by mass or more, and particularly preferably 60 parts by mass or more. Further, the mixing 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, based on 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.

に お い て Also in this case, similarly to the above, the photopolymerization initiator (C), the additive (D), and the crosslinking agent (F) can be appropriately compounded.

は The thickness of the pressure-sensitive adhesive layer is preferably 1 μm or more, and more preferably 5 μm or more. Further, the thickness is preferably 50 μm or less, and more preferably 40 μm or less. When the thickness of the pressure-sensitive adhesive layer is within the above range, the above-mentioned pressure-sensitive adhesive strength can be easily achieved.

(3) Release Sheet In the work processing sheet according to the present embodiment, a release sheet may be laminated on the surface for the purpose of protecting the adhesive surface of the adhesive layer until the adhesive surface is attached to the work. Good. The configuration of the release sheet is arbitrary, and examples thereof include those obtained by subjecting a plastic film to a release treatment 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, a silicone-based, fluorine-based, long-chain alkyl-based or the like can be used, and among these, a silicone-based one that is inexpensive and provides stable performance 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 work processing sheet according to the present embodiment, the 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 a surface of the adhesive layer opposite to the pressure-sensitive adhesive layer, and the adhesive layer diced together with the work is laminated, so that the individualized adhesive layers are laminated. Chips can be obtained. The chip can be easily fixed to an object on which the chip is mounted by the separated adhesive layer. Examples of the material constituting the above-mentioned adhesive layer include a material containing a thermoplastic resin and a low-molecular-weight thermosetting adhesive component, and a material containing a B-stage (semi-cured) thermosetting adhesive component. Preferably, it is used.

ワ ー ク In the work processing sheet according to the present embodiment, a protective film forming layer may be laminated on the adhesive surface of the adhesive layer. In this case, the 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 adhered to the surface of the protective film forming layer opposite to the pressure-sensitive adhesive layer, and the protective film forming layer is diced together with the work to form an individualized protective film. A chip having stacked layers can be obtained. As the work, it is preferable to use a work in which a circuit is formed on one side, and in this case, a protective film forming layer is usually laminated on a surface opposite to the surface on which the circuit is formed. By hardening the individualized protective film forming layer at a predetermined timing, a protective film having sufficient durability can be formed on the chip. The protective film forming layer is preferably made of an uncured curable adhesive.

The work processing sheet according to the embodiment of the present application satisfies the water contact angle and the adhesive force before and after the wiping described above. However, the adhesive layer or the protective film forming layer is laminated on the adhesive layer. In this case, the pressure-sensitive adhesive layer before these layers are laminated may satisfy the water contact angle and the adhesive force before and after the wiping described above.

3. Method for manufacturing work processing sheet The method for manufacturing the work processing sheet according to the present embodiment is not particularly limited, and preferably, the work processing sheet according to the present embodiment has a pressure-sensitive adhesive layer laminated on one side of a base material. It is manufactured by doing.

積 層 Lamination of the pressure-sensitive adhesive layer on one side of the substrate can be performed 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, if desired, a coating liquid further containing a solvent or a dispersion medium are prepared, and a release-treated surface of a release sheet (hereinafter sometimes referred to as a “release surface”). )), A coating film is formed thereon by applying the coating liquid using a die coater, a curtain coater, a spray coater, a slit coater, a knife coater, or the like, and the coated film is dried to form an adhesive layer. be able to. The properties of the coating liquid are not particularly limited as long as coating can be performed, and the coating liquid may contain a component for forming the pressure-sensitive adhesive layer as a solute or may contain a component as a dispersoid. The release sheet in this laminate may be peeled off as a process material, or may be used to protect the adhesive surface of the 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 cross-linking agent, by changing the above-mentioned drying conditions (temperature, time, etc.), or by separately providing a heat treatment, The cross-linking reaction between the active energy ray-curable polymer (A) or the active energy ray non-curable polymer and the cross-linking agent may be advanced to form a cross-linked structure with a desired density in the pressure-sensitive adhesive layer. In order to allow this crosslinking reaction to proceed sufficiently, after the pressure-sensitive adhesive layer is laminated on the substrate by the above method or the like, the obtained work processing sheet is placed in an environment of, for example, 23 ° C. and 50% relative humidity for several days. Curing such as standing still may be performed.

代 わ り 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 directly formed 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 film, and the coating film is dried to form the pressure-sensitive adhesive layer.

4. Method of Using Work Processing Sheet The work processing sheet according to the present embodiment can be used for processing a work. That is, after attaching the adhesive surface of the work processing sheet according to the present embodiment to the work, the work can be processed on the work processing sheet. Depending on the processing, the work processing sheet according to the present embodiment can be used as a back grinding sheet, a dicing sheet, an expanded sheet, a pickup sheet, or the like. Here, examples of the work include a semiconductor member such as a semiconductor wafer and a semiconductor package, and a glass member such as a glass plate.

In addition, when the work processing sheet according to the present embodiment includes the above-described adhesive layer, the work processing sheet can be used as a dicing die bonding sheet. Further, 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 this embodiment, the adhesive force of the work processing sheet to the silicon wafer is in the above-described range, and the water contact angle after wiping is in the above-described range. Even if the constituent adhesive adheres to the work after processing, the adhesive can be satisfactorily removed by running water. Further, when the water contact angle on the adhesive surface before the wiping described above is in the above-described range, the work after processing can be easily separated well. Therefore, the work processing sheet according to the present embodiment is preferably used for processing in which running water is used, and is particularly preferably used for dicing involving supplying running water to a cut portion. is there. That is, the work processing sheet according to the present embodiment is preferably used as a dicing sheet.

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

[Production method of processed work]
The method for manufacturing a processed work according to one embodiment of the present invention includes a laminating step of laminating the surface of the pressure-sensitive adhesive layer of the work processing sheet opposite to the base material and the work, Processing the work on the work sheet to obtain a processed work laminated on the work processing sheet, and irradiating the adhesive layer with active energy rays to cure the adhesive layer An irradiation step of reducing the adhesive force of the work processing sheet to the processed work, and a separation step of separating the processed work from the work processing sheet after irradiation with the active energy ray.

The work processing sheet used in the method of manufacturing a processed work according to the present embodiment, even when the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer adheres to the work after processing, satisfactorily removes the pressure-sensitive adhesive by flowing water. It can be removed and easily separates the processed work. Therefore, according to the method for manufacturing a processed work of the present embodiment, it is possible to efficiently manufacture the processed work.

Hereinafter, each step in the method for manufacturing a processed work of the present embodiment will be described.

(1) Laminating Step The laminating of the work and the work processing sheet in the laminating step can be performed by a conventionally known method. In the case of performing the work dicing in the subsequent processing step, it is preferable to bond a ring frame to a region on the pressure-sensitive adhesive layer side of the work processing sheet on the outer peripheral side of the region where the work is bonded. . The work to be used may be a desired work according to the processed work to be manufactured, and as a specific example, the above-described work can be used.

(2) Processing Step In the processing step, desired processing can be performed on the work, and for example, back grinding, dicing, and the like can be performed. These processes can be performed by a conventionally known method.

When blade dicing using a rotating blade is performed as the above processing, generally, a part of the pressure-sensitive adhesive layer of the work processing sheet is cut together with the work. At that time, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer may be wound up by the blade and adhere to the processed work. However, in the work processing sheet used in the method of manufacturing a processed work according to the present embodiment, as described above, the adhered adhesive can be removed satisfactorily by running water. From this viewpoint, the processing in the present embodiment is preferably dicing, and particularly preferably blade dicing using a rotating blade.

(3) Irradiation Step In the irradiation step, the irradiation condition of the active energy ray is not limited as long as the adhesive force of the work processing sheet to the processed work can be reduced to a desired degree. It can be carried out. Examples of the type of active energy rays used include ionizing radiation, that is, X-rays, ultraviolet rays, and electron beams. Of these, ultraviolet rays, which are relatively easy to introduce irradiation equipment, are preferable.

(4) Separation Step In the separation step, separation is performed by a method according to the type of processing and the obtained processed work. For example, when dicing is performed as processing, and when the chips obtained by singulating the work are obtained by the dicing, the obtained chips are individually separated from the work processing sheet using a conventionally known pickup device. Pick up. Further, in order to facilitate the pickup, the work processing sheet may be expanded to separate the processed works from each other.

(5) Others In the method for manufacturing a processed work of the present embodiment, steps other than the above-described steps may be provided. For example, after the laminating step, a transporting step of transporting the laminated body of the obtained work and the work processing sheet to a predetermined position, a storage step of storing the laminated body for a predetermined period, or the like may be provided. After the separation step, a mounting step or the like for mounting the obtained processed work on a predetermined base or the like may be provided.

The embodiments described above are described to facilitate understanding of the present invention, but not to limit 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 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 described more specifically with reference to 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 Acrylic copolymer obtained by copolymerizing 40 parts by mass of methyl acrylate, 40 parts by mass of 2-methoxyethyl acrylate, and 20 parts by mass of 2-hydroxyethyl acrylate The polymer was reacted with 21.4 g (corresponding to 80 mol% based on the number of moles of 2-hydroxyethyl acrylate) of methacryloyloxyethyl isocyanate (MOI) per 100 g of the acrylic copolymer. Thus, an active energy ray-curable polymer was obtained. The weight average molecular weight (Mw) of the active energy ray-curable polymer was measured by a method described later and found to be 600,000.

100 parts by mass of the obtained active energy ray-curable polymer (in terms of solid content, the same applies hereinafter) and 3 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name "Irgacure 184") as a photopolymerization initiator 4.97 parts by mass of toluene diisocyanate (product name "Coronate L" manufactured by Tosoh Corporation) as a crosslinking agent, and an active energy ray-polymerizable branched polymer (product name "OD" manufactured by Nissan Chemical Industries, Ltd.) as an additive -007 ", weight average molecular weight: 14000) and 0.18 parts by mass in a solvent to obtain a pressure-sensitive adhesive composition.

(2) Formation of pressure-sensitive adhesive layer For the release surface of a release sheet (manufactured by Lintec, product name "SP-PET381031") in which a silicone-based release agent layer is formed on one side of a 38 μm-thick polyethylene terephthalate film After applying the above-mentioned pressure-sensitive adhesive composition and drying it by heating, it was cured at 23 ° C. and 50% RH for 7 days to form a pressure-sensitive adhesive layer having a thickness of 5 μm on the release sheet.

(3) Production of work processing sheet A surface of the pressure-sensitive adhesive layer formed in step (2) opposite to the release sheet, and an 80-μm-thick ethylene-methacrylic acid copolymer (EMAA) film as a base material To obtain a workpiece processing sheet.

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

[Examples 2 to 7 and Comparative Examples 1 to 3]
A work processing sheet 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 water contact angle)
The release sheet was peeled off from the work processing sheets manufactured in Examples and Comparative Examples, and the water contact angle (°) on the exposed surface of the exposed pressure-sensitive adhesive layer was measured using a fully automatic contact angle measurement meter (manufactured by Kyowa Interface Science Co., Ltd.). It was measured under the following conditions using a product name “DM-701”). The results are shown in Table 1 as water contact angles before wiping.
-Purified water droplet volume: 2 µl
・ Measurement time: 3 seconds after dropping ・ Image analysis method: θ / 2 method

Furthermore, the release sheet was peeled off from the work processing sheets produced in Examples and Comparative Examples, exposing the pressure-sensitive adhesive layer. Subsequently, a non-woven fabric (manufactured by Asahi Kasei Corporation, product name “Bencott”, size: 250 mm × 210 mm) is folded to a size of 62.5 mm × 52.5 mm, and the adhesive layer is exposed while 15 mL of methyl ethyl ketone is contained. It was laminated on the surface and allowed to stand for 15 minutes in an environment of 23 ° C. and 50% relative humidity. After standing, the exposed surface of the pressure-sensitive adhesive layer was wiped off with the folded nonwoven fabric as described above, and allowed to stand for 1 hour in the same environment as above to dry the exposed surface. The water contact angle was measured on the surface of the pressure-sensitive adhesive layer on which the wiping treatment was performed, on the side opposite to the substrate under the same conditions as described above. The results are shown in Table 1 as water contact angles after wiping.

[Test Example 2] (Measurement of adhesive strength)
By peeling the release sheet from the work processing sheet manufactured in each of Examples and Comparative Examples, the exposed surface of the exposed pressure-sensitive adhesive layer is superimposed on the mirror surface of a mirror-finished 6-inch silicon wafer, and a 2 kg roller is reciprocated once. The sample was adhered under a load and left for 20 minutes to obtain a sample for measuring adhesive strength.

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

[Test Example 3] (Evaluation of adhesive removeability)
The release sheet was peeled off from the work processing sheet manufactured in each of Examples and Comparative Examples, and a tape mounter (manufactured by Lintec, product name “Adwill RAD 2500m / 12”) was used on the exposed surface of the exposed pressure-sensitive adhesive layer. A polished surface of a 2,000-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 to cut from the 6-inch silicon wafer side while supplying running water to the cutting section under the following dicing conditions.

<Dicing conditions>
・ Dicing device: DFD-6361 manufactured by Disco Corporation
・ Blade: NBC-2H 2050 27HECC manufactured by Disco Corporation
・ Blade width: 0.025 to 0.030 mm
・ Cutting edge: 0.640 to 0.760 mm
-Blade rotation speed: 50,000 rpm
・ Cutting speed: 20mm / sec
・ Cut depth: 15 μm from the surface of the work processing sheet on the side of the adhesive layer
・ Flowing water supply: 1.0 L / min
-Running water temperature: room temperature-Cut size: 10 mm x 10 mm

Twenty chips obtained by the dicing were separated from the work processing sheet, and it was visually confirmed whether or not an adhesive was attached to them. Then, the removability of the pressure-sensitive adhesive was evaluated based on the following criteria. Table 1 shows the results.
〇: No chip to which the adhesive was attached.
X: One or more chips to which the adhesive was adhered.

[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 Examples and Comparative Examples. After completion of dicing, the surface on the work processing sheet side is irradiated with ultraviolet rays (UV) using an ultraviolet irradiation apparatus (manufactured by Lintec, product name "RAD-2000") (illuminance: 230 mW / cm ² , light intensity: 190 mJ / cm ² ) to cure the pressure-sensitive adhesive layer. Thereafter, all the obtained chips were picked up from the work processing sheet. At this time, a needle was pushed up from the surface of the work processing sheet 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 when separating the chip from the work processing sheet was evaluated based on the following criteria. Table 1 shows the results.
〇: I was able to pick up without any problem.
X: The chip could not be picked up properly because the chip could not be separated or the chip was damaged.

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

As can be seen from Table 1, according to the work processing sheet obtained in the example, the pressure-sensitive adhesive could be satisfactorily removed by running water, and the work after processing could be separated well. .

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

Claims (5)

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 water contact angle of the surface of the pressure-sensitive adhesive layer opposite to the substrate is more than 80 °,
   The work processing sheet has an adhesive force to a silicon wafer of 5000 mN / 25 mm or less;
   On the surface of the pressure-sensitive adhesive layer opposite to the substrate, a non-woven fabric containing methyl ethyl ketone was laminated, and allowed to stand at 23 ° C. and a relative humidity of 50% for 15 minutes. The water contact angle measured on the surface that has been dried by wiping the surface and allowed to stand for 1 hour in an environment of 23 ° C. and 50% relative humidity is 50 ° or more and 80 ° or less. Work processing sheet.
2. The work processing sheet according to claim 1, 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.
3. 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. Which contains
   The acrylic copolymer is selected from methyl acrylate, 2-methoxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate and methoxyethylene glycol (meth) acrylate as monomer units constituting the polymer. The work processing sheet according to claim 1, further comprising at least one of the following.
4. The work processing sheet according to any one of claims 1 to 3, wherein the sheet is a dicing sheet.
5. A laminating step of laminating a surface of the pressure-sensitive adhesive layer of the work processing sheet according to any one of claims 1 to 4 opposite to the base material, and a work.
   A processing step of obtaining a processed work laminated on the work processing sheet by processing the work on the work processing sheet,
   Irradiating the pressure-sensitive adhesive layer with active energy rays, curing the pressure-sensitive adhesive layer, an irradiation step of reducing the adhesion of the work processing sheet to the processed work,
   A separating step of separating the processed work from the work processing sheet after the active energy ray irradiation.