KR20200095453A - Sheet for work processing and manufacturing method of processed work - Google Patents

Abstract

As a work processing sheet having a pressure-sensitive adhesive layer composed of an active energy ray-curable pressure-sensitive adhesive formed of a pressure-sensitive adhesive composition containing a substrate and an acrylic copolymer containing (meth)acrylic acid alkoxy ester, the adhesion to a silicon wafer F1, and for processing the work The sheet was immersed in distilled water at 23° C. for 12 hours and dried at 23° C. for 24 hours.
Adhesion reduction rate (%)=｛(F1-F2)/F1｝×100
The sheet for work processing wherein the reduction rate of the adhesive force calculated from is 20% or more and 50% or less. Such a sheet for work processing suppresses the intrusion of water at the interface between the sheet for work processing and the object to be cut or the obtained chip, while the pressure-sensitive adhesive derived from the pressure-sensitive adhesive layer adhered to the object to be cut during processing of the object to be cut, such as a semiconductor wafer. The flowing water can be satisfactorily removed from the object to be cut.

Description

Sheet for work processing and manufacturing method of processed work

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

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

In the above-mentioned dicing process, the dicing blade, the object to be cut, and the sheet for work processing are heated by the frictional heat generated between the rotating dicing blade and the sheet to be cut or workpiece. In addition, in the dicing step, a cutting piece may be formed from a cut object or a sheet for work processing, and this may adhere to the cut object.

For this reason, when performing a dicing process, it is usually performed by supplying water flowing to the cut portion to cool the dicing blade or the like and to remove the generated cutting piece from the object to be cut.

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

Patent Document 1: Japanese Patent No. 5019657

However, when the dicing step was performed using the conventional sheet for work processing disclosed in Patent Document 1, the adhesive derived from the pressure-sensitive adhesive layer of the work processing sheet could not be sufficiently removed from the object to be cut.

Further, in general, due to the supply of water flowing during dicing, water may enter the interface between the sheet for work processing and the object to be cut, or the interface between the sheet for work processing and the obtained chip. When such water intrusion occurs, there is a possibility of chip blowing or chip damage.

This invention is made|formed in view of such a reality, and it suppresses the invasion of water at the interface of a sheet|seat for workpiece|work processing and a to-be-cut object, or the interface of the sheet|seat for work-processing and the obtained chip|tip, while avoiding the said at the time of processing an object to be cut, such as a semiconductor wafer. An object of the present invention is to provide a sheet for work processing capable of satisfactorily removing the pressure-sensitive adhesive from the pressure-sensitive adhesive layer adhered to the cut material from the object to be cut with running water, and a method for manufacturing a processed work using the work-processing sheet. Is done.

In order to achieve the above object, the first invention is a sheet for work processing comprising a substrate and an adhesive layer laminated on one side of the substrate, wherein the adhesive layer is composed of an active energy ray-curable adhesive, , The active energy ray-curable pressure-sensitive adhesive is a pressure-sensitive adhesive formed of a pressure-sensitive adhesive composition containing an acrylic copolymer containing an alkoxy ester of (meth)acrylic acid as a monomer unit constituting the polymer, and the adhesion of the work processing sheet to a silicon wafer is F1 And, after immersing the sheet for work processing in distilled water at 23°C for 12 hours and drying at 23°C for 24 hours, the adhesion of the sheet for work processing to the silicon wafer is F2, the following formula (1)

Reduction rate of adhesive force (%)=｛(F1-F2)/F1｝×100　… (One)

It provides a sheet for work processing, characterized in that the reduction ratio of the adhesive force calculated from 20% or more and 50% or less (Invention 1).

In the work processing sheet according to the above invention (invention 1), the reduction rate of the above-described adhesive force is within the above range, and the invasion of water at the interface between the work processing sheet and the cut object or between the work processing sheet and the obtained chip is suppressed. . In addition, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive composition containing an acrylic copolymer containing an alkoxy ester of (meth)acrylic acid as a monomer unit constituting the polymer, and the pressure-sensitive adhesive has a predetermined affinity for water. At the same time, the reduction rate of the above-described adhesive force is within the above range, and the adhesive force of the adhesive attached to the cutting object is appropriately reduced by contact with water, so that the adhesive attached to the cutting object is good by flowing water. Can be removed.

In the above invention (invention 1), it is preferable that the content of the (meth)acrylic acid alkoxy ester in the acrylic copolymer is 10 parts by mass or more and 85 parts by mass or less (invention 2).

In the above invention (Inventions 1 and 2), the (meth)acrylic acid alkoxy ester is preferably 2-methoxyethyl acrylic acid (Invention 3).

In the above inventions (Inventions 1 to 3), the contact angle of water on the side opposite to the substrate in the pressure-sensitive adhesive layer is preferably 50° or more and 80° or less (Invention 4).

In the above inventions (Inventions 1 to 4), the adhesive force F1 is preferably 1000 mN/25 mm or more and 10000 mN/25 mm or less (Invention 5).

In the above invention (Invention 1 to 5), the adhesive force F2 is preferably 900 mN/25 mm or more and 8000 mN/25 mm or less (Invention 6).

In the above invention (inventions 1 to 6), it is preferable that it is a dicing sheet (invention 7).

In the second aspect of the present invention, in the adhesive layer of the sheet for work processing (inventions 1 to 7), a bonding step of bonding a surface and a work on the side opposite to the base material, and the work on the sheet for work processing A processing step of obtaining a processed work laminated on the work processing sheet by processing, irradiating an active energy ray to the pressure sensitive adhesive layer to cure the pressure sensitive adhesive layer, and the adhesion of the work processing sheet to the processed work There is provided a method for manufacturing a processed work, comprising: an irradiation step for lowering the value and a separation step for separating the processed work from the work sheet after irradiation with active energy rays (invention 8).

The sheet for work processing according to the present invention suppresses the intrusion of water at the interface between the sheet for work processing and the object to be cut or the interface between the sheet for work processing and the obtained chip, while cutting the object to be cut at the time of processing of the object to be cut, such as a semiconductor wafer. The pressure-sensitive adhesive derived from the pressure-sensitive adhesive layer adhered to can be removed satisfactorily from the object to be cut with running water. In addition, according to the method for manufacturing a processed work according to the present invention, it becomes possible to efficiently manufacture the processed work.

Hereinafter, embodiments of the present invention will be described.

[Sheet for work processing]

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

The pressure-sensitive adhesive layer in this embodiment is composed of an active energy ray-curable pressure-sensitive adhesive, and the active energy-ray-curable pressure-sensitive adhesive contains an acrylic copolymer containing an alkoxy (meth)acrylate as a monomer unit constituting the polymer. It is an adhesive formed of a composition.

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

Reduction rate of adhesive force (%)=｛(F1-F2)/F1｝×100　… (One)

The reduction rate of the adhesive force calculated from is 20% or more and 50% or less. In addition, in this specification, both the adhesive force F1 and the adhesive force F2 are the adhesive force measured before the active energy ray is irradiated to the sheet|seat for work processing. In addition, the details of the measuring method of adhesive force F1 and adhesive force F2 are as described in the test example mentioned later.

In the sheet for work processing according to the present embodiment, the pressure-sensitive adhesive layer is formed of the aforementioned pressure-sensitive adhesive composition and exhibits the above-described reduction rate of the adhesive force, and the sheet for work processing according to the present embodiment is used for dicing of a cut object. In this case, it is possible to remove the pressure-sensitive adhesive adhered to the cutting object by flowing water while suppressing the invasion of water into the interface between the work sheet and the object to be cut, or the interface between the work sheet and the obtained chip.

In particular, the reduction rate of the above-described adhesive strength is within the above range, and even when the pressure-sensitive adhesive layer is exposed to flowing water, the adhesive force to the cut object by the pressure-sensitive adhesive layer remains appropriately, and the interface between the sheet for work processing and the object to be cut, Invasion of water into the interface between the sheet for work processing and the obtained chip can be suppressed. Thereby, it becomes possible to satisfactorily suppress chip spatter and chip damage caused by such water intrusion.

On the other hand, the pressure-sensitive adhesive layer is formed of the pressure-sensitive adhesive composition described above, the pressure-sensitive adhesive layer has an appropriate affinity for water, and the reduction rate of the aforementioned adhesion is within the above range, and the pressure-sensitive adhesive derived from the pressure-sensitive adhesive layer is cut in the dicing process. Even when adhering to water, the adhesive strength of the pressure-sensitive adhesive is appropriately lowered by flowing water, so that the pressure-sensitive adhesive can be satisfactorily removed from the object to be cut.

In addition, if the reduction rate of the above-described adhesive force is less than 20%, even after the pressure-sensitive adhesive derived from the pressure-sensitive adhesive layer is exposed to flowing water, the adhesive force of the pressure-sensitive adhesive to the cut object is maintained and the pressure-sensitive adhesive adhered to the cut object is transferred to flowing water. It cannot be removed sufficiently. In addition, when the reduction ratio of the above-described adhesive strength exceeds 50%, the adhesive strength of the pressure-sensitive adhesive layer to the object to be cut is excessively reduced, so that the object to be cut or the resulting chip cannot be kept well on the pressure-sensitive adhesive layer, Peeling or chipping occurs during dicing. From this viewpoint, it is preferable that the reduction ratio of the above-described adhesive force is 23% or more. Moreover, it is preferable that the reduction rate of the adhesive force mentioned above is 40% or less.

1. Physical properties of sheet for work processing

In the work processing sheet according to the present embodiment, the adhesive force F1 described above is preferably 1000 mN/25 mm or more, particularly preferably 2000 mN/25 mm or more, and more preferably 3000 mN/25 mm or more. In addition, the adhesive force F1 is preferably 10000 mN/25 mm or less, particularly preferably 7000 mN/25 mm or less.

In addition, in the sheet for work processing according to the present embodiment, the adhesive force F2 described above is preferably 900 mN/25 mm or more, particularly preferably 1500 mN/25 mm or more, and further preferably 2000 mN/25 mm or more. . Moreover, it is preferable that the said adhesive force F2 is 8000 mN/25 mm or less, and it is especially preferable that it is 5000 mN/25 mm or less.

Since the adhesive force F1 and the adhesive force F2 are each in the above range, it becomes easy to adjust the reduction rate of the adhesive force to the above range.

In addition, in the sheet for work processing according to the present embodiment, the water contact angle of the side opposite to the substrate in the pressure-sensitive adhesive layer (hereinafter, sometimes referred to as “adhesive surface”) is preferably 50° or more, and particularly, It is preferable that it is 55 degrees or more, and it is preferable that it is 60 degrees or more. In addition, the water contact angle is preferably 80° or less, particularly preferably 75° or less, and further preferably 70° or less. When the water contact angle is 50° or more, the affinity of the pressure-sensitive adhesive layer with water is not excessively increased, and thereby, when the sheet for work processing is used for dicing the object to be cut, the sheet for work processing and the object to be cut It becomes possible to effectively suppress the invasion of water into the interface or the interface between the sheet for work processing and the obtained chip. In addition, when the water contact angle is 80° or less, the pressure-sensitive adhesive layer exhibits an appropriate affinity for water, so that the pressure-sensitive adhesive adhered to the cut object can be effectively removed by flowing water. In addition, in this specification, the water contact angle means that it was measured before the active energy ray was irradiated to the sheet for work processing. In addition, the detail of the method of measuring the water contact angle mentioned above is as described in the test example mentioned later.

2. Components of the work sheet

(1) Description

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

For example, the base material is preferably a resin film containing a resin-based material as a main material, and specific examples thereof include an ethylene-vinyl acetate copolymer film; Ethylene-based copolymer films such as ethylene-(meth)acrylic acid copolymer film, ethylene-(meth)acrylate copolymer film, and other ethylene-(meth)acrylic acid ester copolymer films; Polyolefin-based films such as polyethylene films, polypropylene films, polybutene films, polybutadiene films, polymethylpentene films, ethylene-norbornene copolymer films, and norbornene resin films; Polyvinyl chloride-based films such as polyvinyl chloride films and vinyl chloride copolymer films; Polyester-based films such as polyethylene terephthalate film, polybutylene terephthalate film, and polyethylene naphthalate; (Meth)acrylic acid ester copolymer film; Polyurethane films; Polyimide film; Polystyrene film; Polycarbonate films; And fluorine resin films. Examples of the polyethylene film include a low density polyethylene (LDPE) film, a straight chain low density polyethylene (LLDPE) film, and a high density polyethylene (HDPE) film. Moreover, modified films called these crosslinked films and ionomer films are also used. Moreover, the base material may be a laminated film formed by stacking a plurality of the above-described films. In this laminated film, the materials constituting each layer may be of the same type or of different types. As the substrate, it is preferable to use an ethylene-methyl methacrylate copolymer film from the viewpoint of excellent flexibility among the films. In addition, "(meth)acrylic acid" in this specification means both acrylic acid and methacrylic acid. The same is true for other similar terms.

The base material may contain various additives such as flame retardants, plasticizers, antistatic agents, lubricants, antioxidants, colorants, infrared absorbers, ultraviolet absorbers, and ion trapping agents. Although it does not specifically limit as content of these additives, It is preferable to set it as the range in which a base material exhibits a desired function.

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

Although the thickness of a base material can be suitably set according to the method in which the sheet|seat for work processing is used, it is preferable that it is 20 micrometers or more normally, and it is especially preferable that it is 25 micrometers or more. Moreover, it is preferable that the said thickness is 450 micrometers or less normally, and it is especially preferable that it is 300 micrometers or less.

(2) 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 formed from a pressure-sensitive adhesive composition containing an acrylic copolymer containing (meth)acrylic acid alkoxy ester as a monomer unit constituting the polymer. , It is not particularly limited as long as it exhibits a desired adhesive force to the object to be cut and the sheet for work processing can achieve the above-described reduction rate of adhesive force. The pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure sensitive adhesive, and when the object to be adhered to the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer is separated from the pressure-sensitive adhesive surface, the pressure-sensitive adhesive layer is cured by irradiation with active energy rays, thereby forming a sheet for work processing. Adhesion to the object to be cut can be reduced. This facilitates separation of the adhesive surface of the pressure-sensitive adhesive layer from the object to be cut.

The active energy ray-curable pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer may be composed of a polymer having active energy ray-curability as a main component, an active energy ray non-curable polymer (a polymer having no active energy ray curability) and at least one or more active energy A mixture of a monomer and/or oligomer having a pre-curable group may be used as a main component. Further, a mixture of an active energy ray-curable polymer and an active energy ray non-curable polymer may be used. Further, a mixture of a polymer having active energy ray-curable properties and a monomer and/or oligomer having at least one active energy ray-curable group may be used. Further, a mixture of a polymer having an active energy ray-curable polymer, an active energy ray non-curable polymer, and a monomer and/or oligomer having at least one active energy ray-curable group may be used.

In addition, when the active energy ray-curable pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer contains a polymer having the above-described active energy ray-curable property, it is preferable that the (meth)acrylic acid alkoxy ester is contained as a monomer unit constituting the polymer. . In addition, when the active energy ray-curable pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer contains the above-described active energy ray-curable polymer, it is preferable that the (meth)acrylic acid alkoxyester is contained as a monomer unit constituting the polymer. . These details are as described later.

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

The polymer having active energy ray curability is a (meth)acrylic acid ester (co)polymer (A) in which a functional group having active energy ray curability (active energy ray curable group) is introduced in the side chain (hereinafter ``active energy ray curable polymer (A )” in some cases.) is preferable. This active energy ray-curable polymer (A) is preferably obtained by reacting an acrylic copolymer (a1) having a functional group-containing monomer unit with an unsaturated group-containing compound (a2) having a functional group bound to the functional group.

It is preferable that the acrylic copolymer (a1) contains a (meth)acrylic acid alkoxy ester as a monomer unit constituting the polymer. Thereby, when the sheet for work processing is used for dicing an object to be cut, the pressure-sensitive adhesive adhered to the object to be cut can be effectively and satisfactorily removed by flowing water. Specific examples of the (meth)acrylic acid alkoxyester include (meth)acrylate 2-methoxyethyl, (meth)acrylate ethyl carbitol ((meth)acrylate ethoxyethoxyethyl), (meth)acrylate methoxyethylene glycol And the like. Among these, from the viewpoint of being easy to obtain the above-described effect, it is preferable to use 2-methoxyethyl (meth)acrylate, and in particular, it is preferable to use 2-methoxyethyl acrylate.

When the acrylic copolymer (a1) contains a (meth)acrylic acid alkoxyester as a monomer unit constituting the polymer, the content of the (meth)acrylic acid alkoxyester is preferably 10% by mass or more, and particularly preferably 20% by mass or more. And, it is preferable that it is 30 mass% or more. In addition, the content of the (meth)acrylic acid alkoxy ester is preferably 85% by mass or less, particularly preferably 80% by mass or less, and further preferably 70% by mass or less. When the content of the (meth)acrylic acid alkoxy ester is 10% by mass or more, the pressure-sensitive adhesive layer tends to have a predetermined hydrophilicity with respect to water, and the pressure-sensitive adhesive adhered to the cut object is easily removed by flowing water. In addition, since the content of the (meth)acrylic acid alkoxy ester is 85% by mass or less, it is suppressed that the pressure-sensitive adhesive layer exhibits excessive affinity for water, and the sheet for work processing according to the present embodiment is used for dicing the object to be cut. In this case, it is possible to effectively suppress the invasion of water into the interface between the sheet for work processing and the object to be cut, or the interface between the sheet for work processing and the obtained chip. In addition, in this specification, content (mass %) of the above-mentioned (meth)acrylic acid alkoxy ester means content with respect to the whole monomer which comprises acrylic copolymer (a1). In addition, about content (mass %) of the other monomer mentioned later, it shall mean the content with respect to the whole monomer which comprises acrylic copolymer (a1).

Moreover, it is also preferable that the acrylic copolymer (a1) contains methyl acrylate as a monomer unit which comprises a polymer. Since methyl acrylate can also improve the hydrophilicity of the acrylic copolymer (a1), similarly to the (meth)acrylic acid alkoxy ester, the acrylic copolymer (a1) is used as a monomer unit constituting the polymer. In addition, by including methyl acrylate, the effect of suppressing the intrusion of water as described above and the effect of allowing the pressure-sensitive adhesive to be removed by flowing water can be better achieved.

When the acrylic copolymer (a1) contains methyl acrylate as a monomer unit constituting the polymer, the content of methyl acrylate is preferably 10% by mass or more, particularly preferably 20% by mass or more, and also 30% by mass or more desirable. Moreover, it is preferable that content of methyl acrylate is 85 mass% or less. With such content, the effect of suppressing the intrusion of water as described above and the effect of being able to remove the pressure-sensitive adhesive with flowing water can be achieved more effectively.

In addition, when the acrylic copolymer (a1) contains both alkoxy esters of (meth)acrylates and methyl acrylates as monomer units constituting the polymer, the total value of the contents of alkoxy esters of (meth)acrylates and methyl acrylates is 10 It is preferably at least 30% by mass, particularly preferably at least 30% by mass, and more preferably at least 50% by mass. Moreover, it is preferable that the said total value is 90 mass% or less, and it is especially preferable that it is 85 mass% or less. When the above total value is in such a range, when the sheet for work processing according to the present embodiment is used for dicing the object to be cut, the interface between the sheet for work processing and the object to be cut, or the interface between the sheet for work processing and the obtained chip Invasion of water can be effectively suppressed, and at the same time, the pressure-sensitive adhesive adhering to the cutting object can be easily removed by flowing water.

It is preferable that the acrylic copolymer (a1) contains a structural unit derived from a functional group-containing monomer in addition to the above-described (meth)acrylate alkoxyester and methyl acrylate.

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

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

Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. These may be used alone or in combination of two or more.

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

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

Further, the acrylic copolymer (a1) may contain, in addition to the monomers described above, structural units derived from (meth)acrylic acid ester monomers other than methyl acrylate or derivatives thereof (hereinafter sometimes referred to as "arbitrary monomers"). good.

As the (meth)acrylic acid ester monomer, in addition to the (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group, for example, a monomer having an alicyclic structure in the molecule (alicyclic structure-containing monomer) is preferably used. .

As an alkyl (meth)acrylate ester, in particular, an alkyl group having 1 to 18 carbon atoms is an alkyl (meth)acrylate, such as methyl methacrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and (meth)acrylic acid. n-butyl, 2-ethylhexyl (meth)acrylate, and the like are preferably used, and among these, it is preferable to use at least one of methyl methacrylate and n-butyl acrylate from the viewpoint of easy adjustment of adhesive properties. . These may be used individually by 1 type, or may be used in combination of 2 or more type.

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

The acrylic copolymer (a1) preferably contains 50% by mass or more of the above-described arbitrary monomer, particularly preferably 60% by mass or more, and preferably contains 70% by mass or more. Moreover, it is preferable to contain the above-mentioned arbitrary monomer at 99 mass% or less, especially it is preferable to contain 95 mass% or less, and it is preferable to contain 90 mass% or less.

The acrylic copolymer (a1) is preferably obtained by copolymerizing the above-described (meth)acrylic acid alkoxy ester, methyl acrylate, a functional group-containing monomer, and the above-described arbitrary monomer by a conventional method, but 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) is obtained by reacting the acrylic copolymer (a1) having the functional group-containing monomer unit and the unsaturated group-containing compound (a2) having a functional group bonded to the functional group.

The functional group of the unsaturated group-containing compound (a2) can be appropriately selected depending on the kind of functional group of the functional group-containing monomer unit of the acrylic copolymer (a1). For example, when the functional group of the acrylic copolymer (a1) is a hydroxy group, an amino group or a substituted amino group, an isocyanate group or an epoxy group is preferable as the functional group of the unsaturated group-containing compound (a2), and the acrylic copolymer (a1) is When the branched functional group is an epoxy group, the functional group of the unsaturated group-containing compound (a2) is preferably an amino group, a carboxyl group, or an aziridinyl group.

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

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

In the reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2), depending on the combination of the functional group of the acrylic copolymer (a1) and the functional group of the unsaturated group-containing compound (a2), the reaction temperature, pressure, and solvent , Time, the presence or absence of a catalyst, and the type of catalyst can be appropriately selected. As a result, the functional group present in the acrylic copolymer (a1) and the functional group in the unsaturated group-containing compound (a2) react, and the unsaturated group is introduced into the side chain in the acrylic copolymer (a1), and the active energy ray-curable polymer (A) is introduced. Is obtained.

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

Even when the active energy ray-curable pressure sensitive adhesive contains a polymer having active energy ray curability called active energy ray curable polymer (A) as a main component, the active energy ray curable pressure sensitive adhesive is an active energy ray curable monomer and/or oligomer (B ).

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.

As such an active energy ray-curable monomer and/or oligomer (B), for example, monofunctional acrylic acid esters such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate, and trimethyrolpropane tri(metha) )Acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol Multifunctional acrylic acid esters such as di(meth)acrylate, polyethylene glycol di(meth)acrylate, dimethyrol tricyclodecane di(meth)acrylate, polyester oligo(meth)acrylate, polyurethane oligo(meth) And acrylates.

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

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

As the photopolymerization initiator (C), specifically, benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, methyl benzoate benzoate , Benzoin dimethyl ketal, 2,4-diethyl thioxane, 1-hydroxycyclohexylphenylketone, benzyldiphenylsulfide, tetramethylthiurammonosulfide, azobisisobutyronitrile, benzyl, dibenzyl, di Acetyl, β-chloroanthraquinone, (2,4,6-trimethyl benzyl diphenyl) phosphine oxide, 2-benzothiazole-N,N-diethyldithiocarbamate, oligo｛2-hydroxy And -2-methyl-1-[4-(1-propenyl)phenyl]propanone ｝, 2,2-dimethoxy-1,2-diphenylethan-1-one. These may be used alone or in combination of two or more.

The photopolymerization initiator (C) is an active energy ray-curable polymer (A) (when compounding an active energy ray-curable monomer and/or oligomer (B)), an active energy ray-curable polymer (A) and an active energy ray-curable monomer And/or 100 parts by mass of the total amount of oligomer (B)) is preferably used in an amount of 0.1 parts by mass or more, particularly 0.5 parts by mass or more. In addition, when the photoinitiator (C) is compounded with an active energy ray-curable polymer (A) (active energy ray-curable monomer and/or oligomer (B), the active energy ray-curable polymer (A) and the active energy ray-curable 100 parts by mass of the total amount of the monomers and/or oligomers (B)) It is preferably used in an amount of 10 parts by mass or less, particularly 6 parts by mass or less.

In the active energy ray-curable pressure-sensitive adhesive, other components may be appropriately blended in addition to the above components. As other components, an active energy ray non-curable polymer component or an oligomer component (D), a crosslinking agent (E), etc. are mentioned, for example.

Examples of the active energy ray non-curable polymer component or oligomer component (D) include polyacrylic acid esters, polyesters, polyurethanes, polycarbonates, polyolefins, and the like, and have a weight average molecular weight (Mw) of 3000. ~2.5 million polymers or oligomers are preferred. By mixing the component (D) with an active energy ray-curable pressure-sensitive adhesive, adhesion and peelability before curing, strength after curing, adhesion to other layers, storage stability, and the like can be improved. The blending amount of the component (D) is not particularly limited, and is suitably determined in a range of more than 0 parts by mass and 50 parts by mass or less with respect to 100 parts by mass of the active energy ray-curable polymer (A).

As the crosslinking agent (E), 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.

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

Next, the case where the active energy ray-curable pressure-sensitive adhesive is composed mainly of a mixture of an active energy ray non-curable polymer component and a monomer and/or oligomer having at least one active energy ray-curable group will be described below.

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

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

Also in this case, the photopolymerization initiator (C) and the crosslinking agent (E) can be appropriately blended as in the above.

The thickness of the pressure-sensitive adhesive layer is preferably 1 μm or more, and particularly preferably 5 μm or more. In addition, the thickness is preferably 50 μm or less, particularly preferably 40 μm or less. When the thickness of the pressure-sensitive adhesive layer is within the above range, it is easy to achieve the reduction rate of the above-described pressure-sensitive adhesive force.

(3) release sheet

In the sheet for work processing according to the present embodiment, a release sheet may be laminated on the surface for the purpose of protecting the surface until the adhesive surface in the pressure-sensitive adhesive layer is affixed to the cut object. The configuration of the release sheet is arbitrary, and a plastic film is exemplified by 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, silicone-based, fluorine-based, long-chain alkyl-based, or the like can be used, and among these, silicone-based in which stable performance is obtained at low cost 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 absences

In the sheet for work processing according to the present embodiment, an adhesive layer may be laminated on the adhesive surface in the adhesive layer. In this case, the sheet for work processing according to the present embodiment is provided with an adhesive layer as described above, and can be used as a dicing die-bonding sheet. In such a sheet for work processing, a chip on which the individualized adhesive layer is laminated is obtained by attaching an object to be cut on a side opposite to the pressure-sensitive adhesive layer in the adhesive layer and dicing the adhesive layer together with the object to be cut. Can. The chip can be easily fixed to the object on which the chip is mounted by the individualized adhesive layer. As the material constituting the above-mentioned adhesive layer, it is preferable to use a thermoplastic resin and a low molecular weight thermosetting adhesive component, a B-stage (semi-cured) thermosetting adhesive component, or the like.

Moreover, in the sheet|seat for work processing which concerns on this embodiment, the protective film formation layer may be laminated|stacked on the adhesive surface in an adhesive layer. In this case, the sheet|seat for work processing which concerns on this embodiment can be used as a sheet for protective film formation and dicing. In such a sheet for work processing, a chip to which a fragmented protective film forming layer is laminated is obtained by attaching an object to be cut on a side opposite to the pressure-sensitive adhesive layer in the protective film forming layer and dicing the protective film forming layer together with the object to be cut. Can. As the object to be cut, it is preferable that a circuit is formed on one surface, 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. The fragmented protective film-forming layer can be formed by forming a protective film having sufficient durability by curing at a predetermined timing. It is preferable that the protective film forming layer is made of an uncured curable adhesive.

In addition, although the sheet for work processing according to the embodiment of the present application satisfies the above-described reduction rate of adhesive force, when the above-described adhesive layer or protective film forming layer is laminated with respect to the pressure-sensitive adhesive layer, with respect to the pressure-sensitive adhesive layer before such a layer is laminated, It is good if the adhesive force described above is satisfied.

3. Manufacturing method of work sheet

The manufacturing method of the sheet|seat for work processing which concerns on this embodiment is not specifically limited, Preferably, the sheet|seat for work processing which concerns on this embodiment is manufactured by laminating|stacking an adhesive layer on one side side of a base material.

The lamination of the pressure-sensitive adhesive layer on one side of the substrate can be performed according to 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 a coating solution further containing a solvent or a dispersion medium are prepared as desired, and the release-treated surface of the release sheet (hereinafter sometimes referred to as “release surface”) is prepared. An adhesive layer can be formed by coating the coating solution with a die coater, curtain coater, spray coater, slit coater, knife coater or the like to form a coating film and drying the coating film. If the coating solution can be applied, its properties are not particularly limited, and the component for forming the pressure-sensitive adhesive layer may be contained as a solute, or may be contained as a dispersing substance. The release sheet in this laminate may be released as a process material, or may be used to protect the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer until the sheet for work processing is adhered to the object to be cut.

When the coating liquid for forming the pressure-sensitive adhesive layer contains a crosslinking agent, by changing the drying conditions (temperature, time, etc.) described above, or by separately installing a heat treatment, the active energy ray-curable polymer (A) in the coating film Alternatively, the crosslinking reaction of the active energy ray non-curable polymer and the crosslinking agent may be carried out to form a crosslinking structure at a desired existence density in the pressure-sensitive adhesive layer. In order to sufficiently advance this crosslinking reaction, after the pressure-sensitive adhesive layer is laminated on the substrate by the above method or the like, the resulting work sheet is cured, for example, standing at 23° C. for 50% relative humidity for several days. You may do it.

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, a coating film 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 an pressure-sensitive adhesive layer.

4.How to use the sheet for work processing

The sheet|seat for workpiece|work processing concerning this embodiment can be used for the processing of a workpiece|work (cut object). That is, after sticking the adhesive surface of the sheet|seat for workpiece|work processing concerning this embodiment to an object to be cut, the object to be cut can be processed on the sheet|seat for workpiece|work processing. According to the above processing, the sheet for work processing according to the present embodiment can be used as a back grind sheet, dicing sheet, expand sheet, pickup sheet, or the like. Here, examples of the object to be cut include semiconductor members such as semiconductor wafers and semiconductor packages, and glass members such as glass plates.

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

The sheet for work processing according to the present embodiment is easy to remove the pressure-sensitive adhesive with running water even when the pressure-sensitive adhesive derived from the pressure-sensitive adhesive layer adheres to the object to be cut. , It is suppressed that water caused by the flowing water enters the interface between the sheet for work processing and the obtained chip. For this reason, the sheet|seat for workpiece|work processing which concerns on this embodiment is suitable for the process by which flowing water is used, and especially it is suitable for dicing followed by supplying flowing water to a cutting part. That is, it is suitable to use the sheet|seat for work processing which concerns on this embodiment as a dicing sheet.

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

〔Manufacturing method of processed workpieces〕

The manufacturing method of the processed work which concerns on one Embodiment of this invention is the bonding process which bonds the surface and the work of the surface opposite to a base material in the pressure-sensitive adhesive layer of the above-mentioned work processing sheet, and processes a work on the work processing sheet, A processing step of obtaining a processed work laminated on a sheet for work processing, an irradiation process of irradiating an active energy ray with respect to the pressure-sensitive adhesive layer to cure the pressure-sensitive adhesive layer, thereby lowering the adhesion of the work-processing sheet to the processed work, and activity A separation step for separating the processed work from the sheet for work processing after irradiation with energy rays is provided.

The sheet for work processing used in the method for manufacturing a processed work of the present embodiment flows through the pressure-sensitive adhesive attached to the work at the time of processing the work while suppressing the intrusion of water at the interface between the work processing sheet and the work or the work after processing. It can be removed satisfactorily with water. For this reason, according to the manufacturing method of the processed work of this embodiment, it becomes possible to manufacture a processed work efficiently.

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

(1) Bonding process

The work in the bonding step and the work sheet can be bonded together according to a conventionally known technique. Moreover, when dicing a work|work in a subsequent processing process, it is preferable to attach a ring frame to the area|region on the outer peripheral side of the area|region which affixes a work|work on the surface of the pressure-sensitive adhesive layer side of the sheet|seat for work processing. Further, the work to be used may be a desired one depending on the processed work to be manufactured, and as the specific example, the above-described work can be used.

(2) Processing process

In the processing step, desired work can be performed on the work, and, for example, bag grinding, dicing, and the like can be performed. Such processing can be performed according to a conventionally known technique.

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

(3) Irradiation process

In the irradiation step, as long as the adhesive strength of the work sheet to the processed work can be reduced to a desired degree, the conditions for irradiation of the active energy rays are not limited, and can be performed based on a conventionally known technique. As the type of active energy ray to be used, for example, ionizing radiation, that is, X-rays, ultraviolet rays, electron beams, etc. are mentioned, and among them, ultraviolet rays which are relatively easy to introduce irradiation equipment are preferable.

(4) Separation process

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

(5) Other

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

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

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

Example

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

[Example 1]

(1) Preparation of adhesive composition

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

100 parts by mass of the obtained active energy ray-curable polymer (in terms of solid content, the same below), 3 parts by mass of 1-hydroxycyclohexylphenyl ketone (manufactured by BASF, product name ``IRGACURE 184'') as a photopolymerization initiator, and toluene diisocyanate as a crosslinking agent ( TOSOH CORPORATION make, product name "Coronate L") 12.43 parts by mass were mixed in a solvent to obtain a pressure-sensitive adhesive composition.

(2) Formation of adhesive layer

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

(3) Production of work sheet

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

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

(Examples 2 to 7 and Comparative Examples 1 to 3)

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

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

The release sheet was peeled from the sheet for work processing prepared in Examples and Comparative Examples, and the water contact angle (°) at the exposed surface of the exposed pressure-sensitive adhesive layer was measured using a fully automatic contact angle measurement system (manufactured by Kyowa Interface Science Co., Ltd., product name) "DM-701") was measured under the following conditions. Table 3 shows the results.

・The amount of purified water droplets: 2 μl

·Measurement time: 3 seconds after dripping

·Image analysis method: θ/2 method

[Test Example 2] (Measurement of adhesive force)

The peeling sheet was peeled from the sheet for work processing prepared in Examples and Comparative Examples, and the exposed surface of the exposed pressure-sensitive adhesive layer was laminated on the mirror surface of a 6-inch silicon wafer that was mirror-processed, and the load of 2 kg of rollers was reciprocated once. It was put together and left for 20 minutes. Thereafter, the sheet for work processing was peeled from the silicon wafer at a peeling rate of 300 mm/min and a peeling angle of 180°, and the adhesive force F1 (mN/25mm) to the silicon wafer was peeled according to the 180° peeling method according to JIS #Z0237:2009. ). Table 3 shows the results.

Further, the release sheet was peeled from the sheet for work processing prepared in Examples and Comparative Examples, the exposed surface of the exposed pressure-sensitive adhesive layer was immersed in distilled water at 23° C. for 12 hours, and then dried at 23° C. for 24 hours. Thereafter, the exposed surface was laminated on a mirror surface of a 6-inch silicon wafer that had been mirror-processed, and a load of 2 kg was reciprocated once to bond and adhered, and then allowed to stand for 20 minutes. Subsequently, the sheet for work processing is peeled from the silicon wafer at a peeling rate of 300 mm/min and a peeling angle of 180°, and the adhesive force F2 to the silicon wafer after the immersion and drying according to the 180° peeling method according to JIS #Z0237: 2009 (mN/25 mm) was measured. Table 3 shows the results.

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

Reduction rate of adhesive force (%)=｛(F1-F2)/F1｝×100　… (One)

From, the reduction rate (%) of the adhesive force was calculated. Table 3 shows the results.

[Test Example 3] (Evaluation of adhesive removability)

The pressure-sensitive adhesive composition prepared in Examples and Comparative Examples was coated on a release surface of a release sheet (product made from LINTEC Corporation, product name "SP-PET381031"), on which a silicone-based release agent layer was formed on one side of a polyethylene terephthalate film having a thickness of 38 µm. By drying by heating, an adhesive layer having a thickness of 5 μm was formed on the release sheet. 20 pieces of the above-mentioned layered product of a size of 5 mm x 5 mm were cut out from the layered product of the pressure-sensitive adhesive layer and the release sheet thus obtained.

Subsequently, the surface of the pressure-sensitive adhesive layer in each of the 20 pieces obtained as described above was affixed to the polishing surface of a #2000 polished 6-inch silicon wafer (thickness: 150 μm), and then the release sheet was removed from the pressure-sensitive adhesive layer, respectively. Peeled. At the time of the above-mentioned attachment, the small pieces were affixed at least 1 mm apart.

Then, the release sheet was peeled from the sheet for work processing prepared in Examples and Comparative Examples, and a tape mounter (manufactured by LINTEC Corporation, product name "Adwill RAD2500m/12") was applied to the exposed surface of the exposed adhesive layer. By using, a surface opposite to the surface to which the small piece was attached on the 6-inch silicon wafer was attached. Subsequently, using a dicing apparatus (manufactured by DISCO Corporation, product name "DFD-6361"), an operation similar to dicing for cutting to the 6-inch silicon wafer side was performed while supplying water flowing to the cutting portion under the following operating conditions. .

<Operation conditions>

·Dicing device: DISCO Corporation #DFD-6361

· Blade 　　　: DISCO Corporation 　NBC-2H　2050　27HECC

・Blade width: 0.025 ~ 0.030mm

·Protrusion amount of knife tip: 0.640 ~ 0.760mm

・Blade rotation speed: 50000rpm

·Cutting speed: 20mm/sec

・Blade height: 5mm

·Flow water supply volume: 1.0L/min

· Flowing water temperature: Room temperature

·Cutting size: 10mm×10mm

In addition, the above "blade height: 5 mm" means that the distance between the blade and the 6-inch silicon wafer is 5 mm. As is clear from this, in the above operation, cutting of the 6-inch silicon wafer by the blade is performed. Do not.

After completion of dicing, the presence or absence of the pressure-sensitive adhesive originating from the above-mentioned small piece remaining on the silicon wafer was confirmed, and the removeability of the pressure-sensitive adhesive was evaluated based on the following criteria. Table 3 shows the results.

○: No adhesive remained.

X: At least a part of the adhesive remained.

[Test Example 4] (evaluation of water intrusion)

The release sheet was peeled from the sheet for work processing prepared in Examples and Comparative Examples, and was polished to ＃2000 by using a tape mounter (manufactured by LINTEC Corporation, product name "Adwill RAD2500m/12") on the exposed surface of the exposed pressure-sensitive adhesive layer. A polished surface of a 6-inch silicon wafer (thickness: 150 μm) was affixed. Subsequently, using a dicing apparatus (manufactured by DISCO Corporation, product name "DFD-6361"), dicing was performed on the 6-inch silicon wafer side while supplying water flowing to the cutting portion under the following dicing conditions.

<dicing conditions>

·Dicing device: DISCO Corporation #DFD-6361

· Blade 　　　: DISCO Corporation 　NBC-2H　2050　27HECC

・Blade width: 0.025 ~ 0.030mm

·Protrusion amount of knife tip: 0.640 ~ 0.760mm

・Blade rotation speed: 50000rpm

·Cutting speed: 20mm/sec

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

·Flow water supply volume: 1.0L/min

· Flowing water temperature: Room temperature

·Cutting size: 10mm×10mm

After completion of dicing, all the obtained chips were removed from the sheet for work processing, and the side of the pressure-sensitive adhesive layer in the sheet for work processing was observed with a digital microscope (KEYENCE, product name "VHX-1000", magnification: 500 times). , Water penetration at the interface between the chip and the sheet for work processing was evaluated based on the following criteria. Table 3 shows the results.

○: No traces of water intrusion existed on the side of the pressure-sensitive adhesive layer in the sheet for work processing.

X: There was a trace of water intrusion on the side of the pressure-sensitive adhesive layer in the sheet for work processing.

In addition, the details, such as the symbol of Table 1, are as follows.

BA: n-butyl acrylate

MMA: methyl methacrylate

MA: Methyl acrylate

2MEA: 2-methoxyethyl acrylate

HEA: 2-hydroxyethyl acrylate

MOI: Methacryloyloxyethyl isocyanate

As can be seen from Table 3, the sheet for work processing obtained in the Examples was able to satisfactorily remove the pressure-sensitive adhesive with flowing water, and at the same time, it was possible to satisfactorily suppress the intrusion of water.

The sheet|seat for work processing of this invention can be used conveniently for dicing.

Claims (8)

A sheet for work processing comprising a substrate and an adhesive layer laminated on one side of the substrate,
The pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive,
The active energy ray-curable pressure-sensitive adhesive is a pressure-sensitive adhesive formed of a pressure-sensitive adhesive composition containing an acrylic copolymer containing an alkoxy ester of (meth)acrylic acid as a monomer unit constituting the polymer,
The adhesion of the sheet for work processing to a silicon wafer is F1, the work processing sheet is immersed in distilled water at 23° C. for 12 hours, and after drying at 23° C. for 24 hours, the adhesion of the work processing sheet to the silicon wafer is measured. In the case of F2, the following formula (1)
Reduction rate of adhesive force (%)=｛(F1-F2)/F1｝×100. (One)
A sheet for work processing, characterized in that the reduction rate of the adhesive force calculated from is 20% or more and 50% or less. The method of claim 1,
The content of the (meth)acrylic acid alkoxy ester in the acrylic copolymer is 10 parts by mass or more and 85 parts by mass or less. The method according to claim 1 or 2,
The sheet for work processing, wherein the (meth)acrylate alkoxyester is 2-methoxyethyl acrylate. The method according to any one of claims 1 to 3,
In the pressure-sensitive adhesive layer, the water contact angle of the surface on the side opposite to the base material is 50° or more and 80° or less, a sheet for work processing. The method according to any one of claims 1 to 4,
The adhesive force F1 is 1000 mN/25 mm or more and 10000 mN/25 mm or less, a sheet for work processing. The method according to any one of claims 1 to 5,
The adhesive force F2 is 900 mN/25 mm or more and 8000 mN/25 mm or less, a sheet for work processing. The method according to any one of claims 1 to 6,
A sheet for work processing, which is a dicing sheet. A bonding step of bonding a surface opposite to the substrate and a work in the pressure-sensitive adhesive layer of the work processing sheet according to any one of claims 1 to 7,
A processing step of processing the work on the sheet for work processing to obtain a processed work laminated on the work processing sheet,
An irradiation step of irradiating an active energy ray with respect to the pressure-sensitive adhesive layer to cure the pressure-sensitive adhesive layer, thereby lowering the adhesion of the sheet for processing the workpiece to the processed workpiece, and
Separation step of separating the processed work from the sheet for processing the work after irradiation with active energy rays,
It characterized in that it comprises, the manufacturing method of the processed work.