TW202031856A - Workpiece processing sheet - Google Patents

Abstract

This workpiece processing sheet is provided with a substrate and an adhesive layer, wherein: the adhesive layer is configured from an active energy ray-curable adhesive; and when F0 is the adhesive force of the workpiece processing sheet to a silicon wafer and F2 is the adhesive force of the workpiece processing sheet to the silicon wafer after a laminate formed by attaching the workpiece processing sheet to the silicon wafer is heated at 150 DEG C for an hour, and then the adhesive layer constituting the laminate is irradiated with an active energy ray, the adhesive force F0 is 600 mN/25mm to 20,000 mN/25mm inclusive, and the ratio (F2/F0) of the adhesive force F2 to the adhesive force F0 is no greater than 0.66. According to the work processing sheet, while sufficient adhesive force is exhibited to a workpiece when processing the workpiece, the workpiece can be satisfactorily detached after processing after having undergone a heating treatment.

Description

Sheets for workpiece processing

The present invention relates to a sheet for workpiece processing suitable for use in dicing.

Semiconductor wafers such as silicon and gallium arsenide and various components (hereinafter, these are sometimes collectively referred to as "workpieces") are first manufactured in a large diameter state, and then this is cut and separated (diced) into small components (hereinafter, There is a sticking step called "chip") and after each separation (pickup) at the same time, then move to the subsequent step. Among them, semiconductor wafers and other workpieces are stuck on a workpiece processing sheet including a substrate and an adhesive layer, and then undergo the various steps of cutting, cleaning, drying, expanding, crystal taking, and bonding. The sheet for processing workpieces needs to hold the workpiece on the sheet well during processing, and it also needs to have the ability to easily separate the processed workpiece from the sheet.

For the wafers obtained in the above method, there are cases where heat treatment is performed afterwards. For example, the wafer is subjected to treatments such as evaporation, sputtering, and dehumidification baking. And, preset the chip to be used in a high-temperature environment, and conduct a heating test to verify the reliability in the environment. Generally, these heating treatments are performed in a state where the obtained wafers are loaded on a heating tray.

In recent years, the heating treatment of the above-mentioned wafers on the workpiece processing sheet has been studied. That is, it is discussed that after cutting the workpiece on the workpiece processing sheet, the obtained wafer does not need to be transferred to the heating tray, but is loaded on the workpiece processing sheet to directly heat the wafer. In this case, the steps can be simplified.

Patent Documents 1 to 3 disclose adhesive sheets set to be subjected to the above-mentioned heat treatment. In particular, the adhesive sheet disclosed in Patent Document 1 contains an adhesive layer composed of a substrate layer and a radiation-curing adhesive, and the adhesive layer has an adhesive force of 0.5N/20mm or more to SUS304 after being laminated. And until the resin encapsulation step is completed, it will be stimulated and hardened to form a layer with a peel force of 2.0N/20mm or less to the component. In addition, in the adhesive sheet disclosed in Patent Document 2, the adhesive layer is formed of an adhesive composition containing a specific adhesive component and a specific tetrazole compound. In addition, the adhesive sheet disclosed in Patent Document 3 is formed on a heat-resistant substrate, and is formed of a specific acrylic polymer, an energy-ray polymerizable oligomer, a specific polymerization initiator, and a crosslinking agent. Adhesive layer formed by the material for forming the adhesive layer. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 5144634 [Patent Document 2] Japanese Patent No. 5555578 [Patent Document 3] Japanese Patent No. 5565173

[The problem to be solved by the invention]

However, when the wafer heating treatment in the above-mentioned case is performed on the conventional workpiece processing sheet, the adhesion of the workpiece processing sheet to the wafer is increased due to heating. The sheet picks up the wafer well. Such problems cannot be sufficiently solved even if an adhesive sheet with specific heat resistance is used as disclosed in Patent Documents 1 to 3.

In view of the actual situation, the purpose of the present invention is to provide a sheet for workpiece processing that can exhibit sufficient adhesion to the workpiece even when the workpiece is processed, and after heat treatment, the processed workpiece can be separated well. [Means to solve the problem]

In order to achieve the above-mentioned object, the first aspect of the present invention provides a sheet for processing a workpiece, which is a sheet for processing a workpiece having a substrate and an adhesive layer laminated on one surface of the substrate. The adhesive layer is composed of an active energy ray curable adhesive; and the adhesive force of the aforementioned workpiece processing sheet to the silicon wafer is F0, and the aforementioned workpiece processing sheet is attached to the silicon wafer After heating the laminate at 150°C for 1 hour, and then irradiating the adhesive layer constituting the laminate with active energy rays, when the adhesive force of the workpiece processing sheet to the silicon wafer is F2, the adhesive force F0 For 600mN/25mm or more and 20000mN/25mm or less, the ratio (F2/F0) of the aforementioned adhesive force F2 to the aforementioned adhesive force F0 is 0.66 or less (Invention 1).

In the above-mentioned invention (Invention 1), since the above-mentioned adhesive force F0 is in the above-mentioned range, the sheet for workpiece processing of the above-mentioned invention (Invention 1) can exhibit sufficient adhesive force to the workpiece when the workpiece is processed. On the other hand, since the adhesive layer is composed of an active energy ray-curable adhesive, and the ratio of the above-mentioned adhesive force (F2/F0) is in the above-mentioned range, even if the workpiece is heated after processing, it is stuck. In the case of the sheet material for workpiece processing, the active energy rays can be irradiated after passing through, and the adhesion to the processed workpiece can be sufficiently reduced, so that the processed workpiece can be separated well.

In the above invention (Invention 1), after the sheet for workpiece processing is heated at 150°C for 1 hour, the Young's modulus of the adhesive layer at 23°C is E1, and the sheet for workpiece processing After heating at 150°C for 1 hour, and then irradiating the adhesive layer constituting the workpiece processing sheet with active energy rays, when the Young's coefficient of the adhesive layer at 23°C is E2, the Young's coefficient E2 The ratio of the aforementioned Young's coefficient E1 (E2/E1) is preferably 13 or more (Invention 2).

In the above inventions (Inventions 1 and 2), the Young's coefficient of the adhesive layer in the workpiece processing sheet at 23°C is E0, and the workpiece processing sheet is heated at 150°C for 1 hour. When the Young's coefficient of the agent layer at 23°C is E1, the ratio of the aforementioned Young's coefficient E1 to the aforementioned Young's coefficient E0 (E1/E0) is preferably 2.0 or more (Invention 3).

The second aspect of the present invention provides a sheet for processing a workpiece, which is a sheet for processing a workpiece having a substrate and an adhesive layer laminated on one surface of the substrate, characterized in that the adhesive layer is It is composed of an active energy ray curable adhesive; the glass transition temperature of the active energy ray curable adhesive is above -50 ℃ and 10 ℃ or less; and the active energy ray curable adhesive contains a polar group An acrylic copolymer in which the monomer is a constituent monomer (Invention 4).

In the above invention (Invention 4), it is preferable that the acrylic copolymer has a functional group having active energy ray curability introduced into the side chain (Invention 5).

Among the above inventions (Inventions 1 to 5), a diced sheet is preferable (Invention 6). Effect of invention

The sheet for workpiece processing of the present invention can not only exert sufficient adhesion to the workpiece when the workpiece is processed, but also can well separate the processed workpiece after being heated.

Hereinafter, embodiments of the present invention will be described. The sheet for workpiece processing of this embodiment includes a substrate and an adhesive layer laminated on one surface of the substrate. Furthermore, the adhesive layer is composed of an active energy ray-curable adhesive.

1. The nature of the sheet for workpiece processing (1) Adhesion For the workpiece processing sheet of this embodiment, when the adhesion force of the workpiece processing sheet to the silicon wafer is F0, the adhesion force F0 is preferably 600mN/25mm or more, especially 900mN/25mm or more, 1200mN/ More than 25mm is even better. In addition, the adhesion force F0 is preferably 20,000mN/25mm or less, particularly preferably 5,000mN/25mm or less, and more preferably 3000mN/25mm or less. Among them, the above-mentioned adhesive force F0 refers to the initial adhesive force measured on the workpiece processing sheet that has not been subjected to heating or active energy ray irradiation treatment as described later.

Since the sheet for workpiece processing of this embodiment has an adhesive force F0 in the above range, the workpiece can be held well on the sheet for workpiece processing. Therefore, during the processing of the workpiece, even if the impact caused by the processing occurs, the movement or falling of the workpiece after the processing can be suppressed well. In particular, when the adhesion force F0 is 600mN/25mm or more, the workpiece can be easily and well held during processing. On the other hand, since the adhesion force F0 is 20000mN/25mm or less, when the sheet for workpiece processing is irradiated with active energy rays described later, the adhesion to the workpiece after processing can be easily and sufficiently reduced. Therefore, the workpiece can be easily removed The processed work piece is separated from the processing sheet.

In the work-processing sheet of this embodiment, a laminated body formed by bonding the work-processing sheet to a silicon wafer is heated at 150°C for 1 hour, and then irradiated with active energy rays to the adhesive constituting the laminated body After layering, when the adhesion force of the workpiece processing sheet to the silicon wafer is F2, the ratio of the adhesion force F2 to the aforementioned adhesion force F0 (F2/F0) is preferably 0.66 or less, especially 0.2 or less, and 0.15 or less Better still. When the ratio (F2/F0) is 0.66 or less, it is possible to easily and well hold the workpiece during processing and to separate the processed workpiece after the active energy ray is irradiated. In particular, even when the processed workpiece is stuck on the workpiece processing sheet, when the workpiece processing sheet is exposed to heat treatment, it can be easily separated and processed from the workpiece processing sheet. After the workpiece. In addition, the lower limit of the ratio (F2/F0) is not particularly limited, and may be 0.01 or more, for example.

For the workpiece processing sheet of the present embodiment, the above-mentioned adhesive force F2 is preferably 1000mN/25mm or less, particularly preferably 500mN/25mm or less, and even more preferably 150mN/25mm or less. In addition, the adhesive force F2 is preferably 30mN/25mm or more. When the adhesion force F2 is in the above range, the ratio (F2/F0) can be easily adjusted in the above range.

The workpiece processing sheet of this embodiment is when the adhesion force of the workpiece processing sheet to the silicon wafer after the laminated body formed by adhering the workpiece processing sheet to the silicon wafer is heated at 150°C for 1 hour is F1 , Adhesive force F1, preferably above 1000mN/25mm, especially above 2300mN/25mm. In addition, the adhesive force F1 is preferably 5000mN/25mm or less. When the adhesion force F1 is in the above range, the ratio (F2/F0) can be easily adjusted in the above range.

In addition, the measurement methods of the above-mentioned adhesive forces F0, F1, and F2 are detailed as described in the test example described later.

(2) Young's coefficient For the workpiece processing sheet of this embodiment, after the workpiece processing sheet is heated at 150°C for 1 hour, the Young's coefficient of the adhesive layer at 23°C is E1, and the workpiece processing sheet is heated at 150°C After 1 hour, the adhesive layer constituting the workpiece processing sheet is irradiated with active energy rays. When the Young's coefficient of the adhesive layer at 23° C. is E2, the Young's coefficient E2 is relative to the Young's coefficient E1 The ratio (E2/E1) is preferably 13 or more, especially 15 or more, and 18 or more.

As in the foregoing case, the adhesive layer in this embodiment is composed of an active energy ray-curable adhesive. Generally, there are components in active energy ray curable adhesives that are used to achieve active energy ray curability, and a specific reaction is performed by heating, thereby curing the adhesive. For example, when the above-mentioned component is an acryloyl group, the carbon-carbon double bond in the acryloyl group may be cleaved by heating, and the polymerization reaction may proceed. In this case, in the case where the above-mentioned components are reacted by heating, even if the active energy rays are irradiated thereafter, the adhesive layer cannot be cured further well. However, in the workpiece processing sheet of the present embodiment, when the ratio (E2/E1) is in the above range, even after the heat treatment, the active energy rays can be easily irradiated, and the adhesive force can be reduced favorably. In this way, it is possible to effectively prevent the workpiece from falling off unexpectedly before and after the active energy ray is irradiated.

In addition, the upper limit of the ratio (E2/E1) is not particularly limited, and it may be 25 or less, for example.

In the sheet for workpiece processing of this embodiment, when the Young's coefficient of the adhesive layer in the sheet for workpiece processing is E0 at 23°C, the ratio of the Young's coefficient E1 to the Young's coefficient E0 (E1/E0 ), preferably 2.0 or more, especially 2.3 or more, and 2.6 or more. In addition, the aforementioned Young's coefficient E0 means the initial Young's coefficient measured on the adhesive layer that has not been heated or irradiated with active energy rays.

Generally speaking, the adhesive will soften after heating, and there is a tendency to increase the adhesion to the adhesive body. However, in the sheet for workpiece processing of this embodiment, since the ratio (E1/E0) is in the above range, it is unlikely that the adhesive will soften due to heating, and it is possible to effectively prevent excessive increase in adhesion due to heat treatment . As a result, after the adhesive layer is irradiated with active energy rays, the processed workpiece can be separated well.

In addition, the upper limit of the ratio (E1/E0) is not particularly limited, and may be 3.5 or less, for example.

In the sheet for workpiece processing of the present embodiment, the Young's coefficient E0 is preferably 2.0 MPa or more, especially 2.3 MPa or more, and even more preferably 2.5 MPa or more. In addition, the Young's coefficient E0 is preferably 15 MPa or less, particularly 10 MPa or less, and even more preferably 5 MPa or less. When Young's coefficient E0 is in the above range, the ratio (E1/E0) can be easily adjusted in the above range.

In the sheet material for workpiece processing of this embodiment, the Young's coefficient E1 is preferably 5.0 MPa or more, particularly 6.0 MPa or more, and even more preferably 7.0 MPa or more. In addition, the Young's coefficient E1 is preferably 100 MPa or less, particularly preferably 50 MPa or less, and even more preferably 10 MPa or less. When Young's coefficient E1 is in the above range, the ratio (E2/E1) and the ratio (E1/E0) can be easily adjusted in the above range.

In the sheet for workpiece processing of the present embodiment, the Young's coefficient E2 is preferably 100 MPa or more, particularly preferably 130 MPa or more, and even more preferably 140 MPa or more. In addition, the Young's coefficient E2 is preferably 300 MPa or less, particularly preferably 250 MPa or less, and even more preferably 200 MPa or less. When Young's coefficient E2 is in the above range, the ratio (E2/E1) can be easily adjusted in the above range.

In addition, the measurement methods of the Young's coefficients E0, E1, and E2 described above are as described in the test examples described later in detail.

2. Components of sheet material for workpiece processing (1) Substrate In the work-processing sheet of this embodiment, the base material can exhibit the desired function in the step of using the work-processing sheet, and it is preferable that the active energy rays irradiated by the hardening of the adhesive layer can perform well. It is only necessary to have specific heat resistance at the same time, and there is no particular limitation.

For example, the substrate is preferably a resin film whose main material is a resin-based material. Specific examples include ethylene-vinyl acetate copolymer film; ethylene-(meth)acrylic acid copolymer film, ethylene-( Ethylene copolymer films such as methyl meth)acrylate copolymer films and other ethylene-(meth)acrylate copolymer films; polyethylene film, polypropylene film, polybutene film, polybutadiene film, Polyolefin-based films such as polymethylpentene film, ethylene-norbornene copolymer film, norbornene resin film, cycloolefin resin film, etc.; polychlorinated vinyl chloride film, chlorinated ethylene copolymer film, etc. Ethylene film; Polyester film such as polyethylene terephthalate film, polybutylene terephthalate film, polycyclohexane dimethyl terephthalate, polyethylene naphthalate, etc.; (Meth) acrylate copolymer film; polyurethane film; polyimide film; polystyrene film; polycarbonate film; fluororesin film; polyphenylene sulfide film, etc. Examples of polyethylene films include low-density polyethylene (LDPE) films, linear low-density polyethylene (LLDPE) films, and high-density polyethylene (HDPE) films. In addition, cross-linked films of these substances and modified films of ionic polymer films can also be used. In addition, the substrate may be a laminated film obtained by laminating the above-mentioned films in plural. In this type of laminated film, the materials constituting each layer may be of the same type or different types. As a base material, among the above films, from the viewpoint of good light transmittance and heat resistance of active energy rays, annealed polyester film, heat resistant polyester film, and polycarbonate film are used. , Polyphenylene sulfide film and cycloolefin resin film are preferred. Furthermore, "(meth)acrylic acid" in the specification of this case refers to both acrylic acid and methacrylic acid. Other similar terms are also the same.

The substrate may also contain various additives such as flame retardants, plasticizers, antistatic agents, lubricants, antioxidants, colorants, infrared absorbers, ultraviolet absorbers, ion chelating agents and the like. The content of these additives is not particularly limited, and is preferably within a range that can exhibit desired functions in the substrate.

On the surface of the base material laminated adhesive layer, in order to improve the adhesion with the adhesive layer, surface treatment such as primer treatment, corona treatment, plasma treatment, etc. can also be applied.

The thickness of the substrate can be appropriately set depending on the method of using the workpiece processing sheet. Generally, it is preferably 20 μm or more, and more preferably 25 μm or more. In addition, the thickness is generally preferably 450 μm or less, and more preferably 300 μm or less.

(2) Adhesive layer In the workpiece processing sheet of this embodiment, the adhesive layer is composed of an active energy ray-curable adhesive. Since the adhesive layer is composed of an active energy ray-curable adhesive, the active energy ray can be irradiated to harden the adhesive layer and reduce the adhesive force to the bonding body of the sheet for workpiece processing. In this case, the processed workpiece can be easily separated from the workpiece processing sheet.

In addition, the adhesive layer in this embodiment is preferably capable of achieving the aforementioned adhesive force. From this point of view, the adhesive layer in the present embodiment has a glass transition temperature of the active energy ray-curable adhesive that constitutes the adhesive layer, which is above -50°C and 10°C or less, and the active energy ray hardenability The adhesive preferably contains an acrylic copolymer containing a monomer having a polar group as a constituent monomer. With an adhesive layer composed of such an active energy ray-curable adhesive, it is possible to easily achieve the aforementioned adhesive force for the workpiece processing sheet.

From the viewpoint that the aforementioned adhesive force can be achieved more easily from the sheet for workpiece processing, the above-mentioned glass transition temperature is particularly preferably -20°C or higher, and more preferably -15°C or higher. In addition, from the same viewpoint, the above-mentioned glass transition temperature is particularly preferably 5°C or less, and more preferably 3°C or less. In addition, the measurement method of the said glass transition temperature is as described in the test example mentioned later in detail.

The active energy ray curable adhesive constituting the adhesive layer can be a polymer with active energy ray curability as the main component, or an active energy ray non-curable polymer (that is, a polymer without active energy ray curability) and A mixture containing at least one or more monomers and/or oligomers having active energy ray hardening groups as the main component.

Hereinafter, first, the case where the active energy ray-curable adhesive has an active energy ray-curable polymer as the main component will be described.

Active energy ray-curable polymer, with active energy ray-curable functional group (active energy ray-curable group) introduced into the side chain (meth)acrylate (co)polymer (A) (there are below It is better to call it "active energy ray curable polymer (A)"). This type of active energy ray curable polymer (A) consists of an acrylic copolymer (a1) containing a functional group-containing monomer unit and an unsaturated group-containing compound (a1) containing a functional group bonded to the functional group ( a2) The reaction is better.

As the above-mentioned functional group-containing monomers, monomers containing polymerizable double bonds and functional groups such as hydroxyl, carboxyl, amino, amido, benzyl, and glycidyl groups in the molecule are preferred. It is better to use monomers containing functional groups as hydroxyl groups (hydroxyl-containing monomers).

Examples of the above-mentioned hydroxyl-containing monomers include: 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (methyl) ) 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc. Among them, 2-hydroxyethyl acrylate is preferably used. Moreover, these can be used individually or in combination of 2 or more types.

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

Examples of the above-mentioned amine group-containing monomers or amide group-containing monomers include aminoethyl (meth)acrylate, n-butylaminoethyl (meth)acrylate, and the like. These can be used alone or in combination of two or more kinds.

The above-mentioned acrylic copolymer (a1) is a structural unit derived from a monomer containing the above-mentioned functional group. The content is preferably at least 1% by mass, especially at least 5% by mass, and even more preferably at least 10% by mass. . In addition, the acrylic copolymer (a1), which is a structural unit derived from a monomer containing the aforementioned functional group, preferably has a content of 35% by mass or less, and more preferably a content of 30% by mass or less. When the functional group-containing monomer contained in the acrylic copolymer (a1) is in the above range, the desired active energy ray curable polymer (A) can be easily formed.

The acrylic copolymer (a1), as described above, preferably contains a polar group-containing monomer (polar group-containing monomer) as a monomer unit constituting the polymer. In this case, the polarity of the obtained active energy ray-curable adhesive can be increased, so the aforementioned adhesive force can be easily achieved.

Examples of polar group-containing monomers include acryloylmorpholine, isobornyl acrylate, methyl methacrylate, vinyl acetate, benzyl acrylate, glycidyl methacrylate, etc. In particular, it is better to use acrylomorpholine or isobornyl acrylate.

The acrylic copolymer (a1), a constituent unit derived from the above-mentioned polar group-containing monomer, preferably has a content of 3.0% by mass or more, particularly preferably a content of 5.0% by mass or more, and even more preferably a content of 8.0% by mass or more. In addition, the acrylic copolymer (a1), a structural unit derived from the above-mentioned polar group-containing monomer, preferably has a content of 12.0% by mass or less. When the acrylic copolymer (a1) contains the above-mentioned polar group-containing monomer in the above-mentioned range, the polarity of the obtained active energy ray-curable adhesive can be effectively increased, and therefore the aforementioned adhesive force can be easily achieved.

In addition, the acrylic copolymer (a1), as a monomer unit constituting the polymer, preferably contains a monomer (Tg adjusting monomer) for adjusting the glass transition temperature (Tg) of the active energy ray curable adhesive. In this case, the resulting active energy ray-curable adhesive can easily have the aforementioned glass transition temperature (Tg). As examples of preferable monomers having both Tg adjusting monomers, the polar group-containing monomers mentioned above can be cited. Among them, it is particularly preferable to use acrylomorpholine or isobornyl acrylate.

The glass transition temperature of the aforementioned Tg adjusting monomer is preferably 30°C or higher, especially 50°C or higher, and more preferably 90°C or higher. In addition, the Tg adjusts the glass transition temperature of the monomer, preferably 200°C or less, particularly preferably 180°C or less, and more preferably 150°C or less. When a Tg adjusting monomer having a glass transition temperature in these ranges is used, the glass transition temperature of the active energy ray-curable adhesive can be easily adjusted within the aforementioned range. In addition, in the specification of this case, the glass transition temperature of a monomer refers to the glass transition temperature measured by a homogeneous polymer composed of the monomer alone.

In addition, the above-mentioned Tg adjusts the dissolution parameter (SP value) of the monomer, preferably 9.8 or more, particularly preferably 9.9 or more, and more preferably 10.0 or more. When the SP value of the Tg adjusting monomer is above 9.8, the adhesive force of the workpiece processing sheet can be easily adjusted within the aforementioned range, and the initial adhesive force F0 can be easily adjusted within the aforementioned range. Therefore, the workpiece can be easily held on the workpiece processing sheet during processing. In addition, the upper limit of the dissolution parameter (SP value) is not particularly limited, and it may be 11 or less, for example.

The acrylic copolymer (a1), a structural unit derived from the above-mentioned Tg adjusting monomer, preferably has a content of 3.0% by mass or more, particularly preferably a content of 5.0% by mass or more, and even more preferably a content of 8.0% by mass or more. In addition, the acrylic copolymer (a1), a constituent unit derived from the above-mentioned Tg adjusting monomer, preferably has a content of 12.0% by mass or less. When the acrylic copolymer (a1) contains the Tg adjusting monomer in the above range, the glass transition temperature of the obtained active energy ray-curable adhesive can be easily adjusted within the above range.

The acrylic copolymer (a1), as a monomer unit constituting the polymer, preferably uses an alkyl (meth)acrylate monomer having an alkyl group of 1 to 20 carbon atoms. As such an alkyl (meth)acrylate monomer, an alkyl (meth)acrylate monomer having an alkyl group of 1 to 18 carbon atoms is particularly preferred. In addition, from the viewpoint of easily obtaining an adhesive with good heat resistance, an alkyl (meth)acrylate monomer having an alkyl group with 8 or more carbon atoms is preferred. As a preferable example of the alkyl (meth)acrylate monomer with the carbon number of the alkyl group being 1 to 20, for example, methyl methacrylate, ethyl (meth)acrylate, and propylene (meth)acrylate can be mentioned. Ester, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc. These can be used individually by 1 type, and can also be used in combination of 2 or more types.

The acrylic copolymer (a1) is a structural unit derived from the above-mentioned alkyl (meth)acrylic acid alkyl ester monomer with a carbon number of 1 to 20. The content is preferably at least 50% by mass, especially the content is 60 It is more preferable that the mass% is more than 70 mass%. In addition, the acrylic copolymer (a1) is a structural unit derived from the above-mentioned alkyl (meth)acrylic acid alkyl ester monomer having a carbon number of 1 to 20, and the content is preferably 99% by mass or less, especially The content is more preferably 95% by mass or less, and even more preferably the content is 90% by mass or less.

The acrylic copolymer (a1) is preferably obtained by copolymerizing the above-described monomers or their derivatives by conventional methods. In addition to such monomers, monomers with alicyclic structures (including alicyclic Structural monomer), dimethyl acrylamide, vinyl formate, styrene and other copolymers.

Examples of the above-mentioned alicyclic structural monomers include: cyclohexyl (meth)acrylate, dicyclopentyl (meth)acrylate, adamantyl (meth)acrylate, isocampan (meth)acrylate Ester, dicyclopentanyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, etc. These can be used individually by 1 type, and can also be used in combination of 2 or more types.

The acrylic copolymer (a1) containing the functional group-containing monomer unit is reacted with the unsaturated group-containing compound (a2) containing the functional group bonded to the functional group to obtain active energy ray curable polymerization物(A).

The functional group contained in the unsaturated group-containing compound (a2) may be appropriately selected depending on the type of the functional group of the functional group-containing monomer unit contained in the acrylic copolymer (a1). For example, when the functional group contained in the acrylic copolymer (a1) is a hydroxyl group, an amino group or an amide group, the functional group contained in the unsaturated group-containing compound (a2) is preferably an isocyanate group or an epoxy group ; In the case where the functional group contained in the acrylic copolymer (a1) is a glycidyl group, the functional group contained in the unsaturated group-containing compound (a2) is an amino group, a carboxyl group or an aziridinyl group (aziridinyl) good.

Furthermore, in the above-mentioned unsaturated group-containing compound (a2), the active energy ray polymerizable carbon-carbon double bond contains at least one in a molecule, preferably 1 to 6, and 1 to 4 more Better. As specific examples of such unsaturated group-containing compounds (a2), for example, isocyanate-2-methacryloxyethyl, isocyanate methyl isopropenyl-α,α-dimethyl Methyl benzyl, methacryloyl isocyanate, allyl isocyanate, 1,1-(diacryloyloxymethyl) ethyl isocyanate; with diisocyanate compound or polyisocyanate compound and (form (M) Acrylic monoisocyanate compound obtained by reacting hydroxyethyl acrylate; Acrylic monoisocyanate compound obtained by reacting diisocyanate compound or polyisocyanate compound with polyol compound and hydroxyethyl (meth)acrylate; (methyl) Glycidyl acrylate; (meth)acrylic acid, (meth)acrylic acid-2-(1-aziridinyl)ethyl, 2-vinyl-2-oxazoline, 2-isopropenyl-2- Oxazoline and so on.

The unsaturated group-containing compound (a2) is preferably 50 mol% or more relative to the number of moles of the functional group-containing monomer of the acrylic copolymer (a1), especially 60 mol% or more. Better, more than 70 mol% is even better. In addition, the above-mentioned unsaturated group-containing compound (a2) is preferably 95 mol% or less, especially 93 mol%, relative to the number of moles of the functional group-containing monomer of the acrylic copolymer (a1). The following is better, and 90 mol% or less is even better.

In the reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2), the difference between the functional group contained in the acrylic copolymer (a1) and the functional group contained in the unsaturated group-containing compound (a2) can be seen Combination, appropriate selection of reaction temperature, pressure, solvent, time, presence or absence of catalyst, and type of catalyst. In this case, the functional groups existing in the acrylic copolymer (a1) will react with the functional groups in the unsaturated group-containing compound (a2) to introduce the unsaturated groups into the acrylic copolymer (a1) Chain to obtain active energy ray-curable polymer (A).

The weight average molecular weight (Mw) of the active energy ray curable polymer (A) obtained in this case is preferably 10,000 or more, especially 150,000 or more, and more preferably 200,000 or more. In addition, the weight average molecular weight (Mw) is preferably 1.5 million or less, and more preferably 1 million or less. Furthermore, the weight average molecular weight (Mw) in the specification of this case is measured by colloidal filtration chromatography (GPC method) and then converted into standard polystyrene values.

Active energy ray hardening adhesive, even if the main component is active energy ray hardening polymer (A), the active energy ray hardening adhesive can also contain active energy ray hardening The monomer and/or oligomer (B).

As active energy ray curable monomers and/or oligomers (B), for example, esters of polyols and (meth)acrylic acid can be used.

Examples of the 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, neopentaerythritol tri(meth)acrylate, neopentaerythritol tetra(meth)acrylate, dineopentylerythritol hexa(meth)acrylate, 1,4-Butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dimethylol tricyclodecane Multifunctional acrylates such as di(meth)acrylate; polyester oligo(meth)acrylate, polyurethane oligo(meth)acrylate, etc.

In the case of preparing active energy ray-curable polymer (A), active energy ray-curable monomer and/or oligomer (B), active energy ray-curable monomer in the active energy ray-curable adhesive And/or the content of the oligomer (B) is preferably more than 0 parts by mass relative to 100 parts by mass of the active energy ray-curable polymer (A), especially 60 parts by mass or more. In addition, the content is preferably 250 parts by mass or less with respect to 100 parts by mass of the active energy ray curable polymer (A), and more preferably 200 parts by mass or less.

Among them, when the active energy ray used for curing the active energy ray curable adhesive is ultraviolet light, it is better to add a photopolymerization initiator (C). When the photopolymerization initiator (C) is used , Can reduce the polymerization hardening time and light exposure.

The photopolymerization initiator (C) in this embodiment preferably has a 5% weight loss temperature of 200°C or higher, particularly preferably 210°C or higher, and even more preferably 220°C or higher. When the photopolymerization initiator (C) exhibiting a 5% weight loss temperature of 200°C or higher is used, the adhesive force of the workpiece processing sheet can be easily adjusted within the aforementioned range. In particular, it can be easily adjusted after heating and irradiation The adhesive force F2 after the active energy line is in the aforementioned range. In this case, even in the case of heat treatment, the processed workpiece can be easily separated from the workpiece processing sheet. In addition, the upper limit of the 5% weight loss temperature is not particularly limited. For example, it is preferably 300°C or less, particularly 280°C or less, and even more preferably 250°C or less. In addition, the method for measuring the above-mentioned 5% weight loss temperature is described in detail in the examples described later.

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 (benzoin benzoic acid), benzoin methyl benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthene copper, 1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide (benzyldiphenyl sulfide), tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl-(benzyl), dibenzyl-(dibenzyl), diacetyl-(diacetyl), β-green anthraquinone, oxidized (2,4,6-trimethyl benzyl diphenyl) phosphine oxide ((2,4,6-trimethyl benzyl diphenyl) phosphine oxide), 2-benzothiazole-N,N -Diethyldithiocarbamate (2-benzothiazole-N, N-diethyldithiocarbamate), oligomer {2-hydroxy-2-methyl-1-[4-(1-propenyl)phenyl]acetone} (oligo{2-hydroxy-2-methyl-1-[4-(1-propenyl)phenyl] propanone}), 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-Hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propanyl)-benzyl]phenyl}-2-methyl-propan-1-one and the like. Among them, the use of 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propanyl)-benzyl]phenyl}-2-methyl-propane-1-one is more good. These may be used alone or in combination of two or more kinds.

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

In the active energy ray curable adhesive, in addition to the above-mentioned components, other components can be appropriately prepared. Examples of other components include active energy ray non-curable polymer components or oligomer components (D), crosslinking agents (E), and the like.

Examples of the active energy ray non-curable polymer component or oligomer component (D) include: polyacrylate, polyester, polyurethane, polycarbonate, polyolefin, etc., with a weight average molecular weight (Mw) of 3000 to 2.5 million polymers or oligomers are better. When the component (D) is prepared in an active energy ray curable adhesive, it can improve the adhesion and peelability before curing, the strength after curing, the adhesion to other layers, and the storage stability. The preparation amount of the component (D) is not particularly limited, and it can be appropriately determined in the range of more than 0 parts by mass and 50 parts by mass relative 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 contained in 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, propylene compounds, hydrazine compounds, aldehyde compounds, oxazoline compounds, metal alkoxide compounds, and metal chelate compounds. Compound compounds, metal salts, ammonium salts, reactive phenol resins, etc.

The preparation amount of the crosslinking agent (E) is preferably 0.01 parts by mass or more relative to 100 parts by mass of the active energy ray curable polymer (A), and more preferably 1 part by mass or more. In addition, the preparation amount of the crosslinking agent (E) is preferably 20 parts by mass or less with respect to 100 parts by mass of the active energy ray curable polymer (A), and more preferably 17 parts by mass or less.

Secondly, the following is the active energy ray curable adhesive, the main component is a mixture of active energy ray non-curable polymer components and monomers and/or oligomers containing at least one active energy ray curable group Circumstances, explain.

As the active energy ray non-curable polymer component, the same components as the aforementioned acrylic copolymer (a1) can be used.

The monomer and/or oligomer containing at least one or more active energy ray hardening groups can be selected from the same thing as the aforementioned component (B). The preparation ratio of the active energy ray non-curable polymer component and the monomer and/or oligomer containing at least one or more active energy ray curable groups, relative to 100 parts by mass of the active energy ray non-curable polymer component, contains The monomer and/or oligomer of at least one active energy ray curable group is preferably 1 part by mass or more, particularly 60 parts by mass or more. In addition, the preparation ratio is preferably 200 parts by mass or less of monomers and/or oligomers containing at least one active energy ray curable group relative to 100 parts by mass of the active energy ray non-curable polymer component. , Particularly more preferably 160 parts by mass or less.

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

The thickness of the adhesive layer is preferably 1 μm or more, more preferably 5 μm or more. In addition, the thickness is preferably 50 μm or less, and more preferably 40 μm or less. When the thickness of the adhesive layer is in the above range, the aforementioned adhesive force can be easily achieved.

(3) Peeling sheet The workpiece processing sheet of this embodiment is used to protect the surface between the surface of the adhesive layer opposite to the substrate (hereinafter, sometimes referred to as "adhesive surface"). A release sheet may be laminated on the surface. The release sheet may have any configuration, for example, a plastic film may be peeled off with a release agent. Specific examples of plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene terephthalate; and polypropylene or polyethylene Such as polyolefin film. The release agent can be used: silicone-based, fluorine-based, long-chain alkane-based, etc. Among them, silicone-based products that are inexpensive and can obtain stable performance are preferred. The thickness of the release sheet is not particularly limited, but it can usually be 20 μm or more and 250 μm or less.

(4) Other components In the sheet for workpiece processing of this embodiment, an adhesive layer may be laminated on the adhesive surface of the adhesive layer. In this case, the workpiece processing sheet of this embodiment can be used as a dicing/bonding wafer when it has the adhesive layer as described above. For this kind of workpiece processing sheet, when the workpiece is pasted on the surface of the adhesive layer opposite to the adhesive layer to cut the workpiece and the adhesive layer at the same time, the individualized sheet can be obtained to laminate the adhesive Layer of wafers. The chip can be easily fixed to the object to be carried by the adhesive layer that is individualized by the sheet. As the material constituting the adhesive layer, it is preferable to use a thermosetting adhesive component containing a thermoplastic resin and low molecular weight, or a thermosetting adhesive component containing a B stage (semi-hardened).

In addition, in the sheet for workpiece processing of this embodiment, a protective film forming layer may be laminated on the adhesive surface of the adhesive layer. In this case, the work processing sheet of this embodiment can be used as a protective film formation and cutting sheet. This kind of workpiece processing sheet is to stick the workpiece on the side opposite to the adhesive layer in the protective film forming layer, so the workpiece and the protective film forming layer are cut at the same time, and the obtained wafer will be laminated and individualized by the sheet The protective film forming layer. As the sheet, it is preferable to use one having a circuit formed on one surface. In this case, usually, a protective film forming layer is laminated on the surface opposite to the surface on which the circuit is formed. The protective film forming layer that has been individualized by the sheet is hardened by a predetermined cutting, so that a protective film with sufficient durability can be formed on the wafer. The protective film forming layer is preferably composed of an uncured curable adhesive.

In addition, the sheet material for workpiece processing of this embodiment preferably satisfies the aforementioned conditions in terms of adhesion. When the adhesive layer or protective film forming layer is laminated on the adhesive layer, the adhesive layer is laminated Before layering, it is better to satisfy the aforementioned adhesion.

3. Manufacturing method of sheet for workpiece processing The manufacturing method of the work processing sheet of the present embodiment is not particularly limited. The work processing sheet of the present embodiment is preferably manufactured by laminating an adhesive layer on one surface of the base material.

Laminating the adhesive on one surface of the substrate can be implemented by a generally known method. For example, it is better to transfer the adhesive layer formed on the release sheet to one surface of the substrate. In this case, first prepare a coating solution containing the adhesive composition constituting the adhesive layer and another solvent or dispersion solvent as necessary, and peel off the surface of the sheet after the peeling treatment (hereinafter sometimes referred to as "peeling surface") ), and then apply the coating liquid with a die coater, curtain coater, spray coater, slit coater, knife coater, etc. to form a coating film, and the coating film is dried, namely Can form an adhesive layer. The coating liquid may be applied as long as it can be applied, and is not particularly limited in terms of properties. When it contains a component for forming the adhesive layer as a solute, it may contain a dispersed solute in some cases. The peeling sheet in the laminate can be regarded as an engineering material to be peeled off, and it can also be used to protect the adhesive surface of the adhesive layer until the workpiece processing sheet is attached to the workpiece.

When the coating solution used to form the adhesive layer contains a crosslinking agent, the above drying conditions (temperature, time, etc.) can be changed, or additional heating treatment can be used to make the active energy rays in the coating hardenable The polymer (A) or the active energy ray non-curing polymer undergoes a cross-linking reaction with the cross-linking agent to form a desired density in the adhesive layer to form a cross-linked structure. In order to allow the crosslinking reaction to proceed sufficiently, after laminating the adhesive on the substrate by the above-mentioned method or the like, the resulting workpiece processing sheet may be placed at 23°C and 50% relative humidity. The environment is matured in a few days.

Instead of transferring the adhesive layer formed on the release sheet to one surface of the substrate as described above, the adhesive layer can also be directly formed on the substrate. In this case, the coating solution used to form the aforementioned adhesive layer is coated on one surface of the substrate to form a coating film, and then the coating film is dried to form the adhesive layer.

4. How to use sheets for workpiece processing The sheet for workpiece processing of this embodiment can be used to process workpieces. That is, after the adhesive surface of the workpiece processing sheet of this embodiment is adhered to the workpiece, the workpiece can be processed on the workpiece processing sheet. According to this processing, the workpiece processing sheet of the present embodiment can be used as a back grinding sheet, a dicing sheet, an expanded sheet, and a wafer removal sheet. Among them, workpieces include semiconductor components such as semiconductor wafers and semiconductor packages; glass components such as glass plates.

In addition, when the workpiece processing sheet of this embodiment is provided with the aforementioned adhesive layer, the workpiece processing sheet can be used as a dicing/bonding wafer. In addition, when the work processing sheet of the present embodiment includes the aforementioned protective film forming layer, the work processing sheet can be used as a protective film forming and cutting sheet.

When the processing of the workpiece on the workpiece processing sheet of this embodiment is completed, and the workpiece processing sheet is separated from the processed workpiece, the adhesive layer in the workpiece processing sheet is irradiated with active energy before the separation Line is better. In this case, the adhesive layer can be hardened, so the adhesive force of the workpiece processing sheet to the processed workpiece can be well reduced, and the processed workpiece can be easily separated.

As the above-mentioned active energy rays, for example, electromagnetic waves or charged particle beams having energy quantum can be used. Specifically, ultraviolet rays, electron beams, etc. can be used. In particular, ultraviolet rays that are easy to handle are preferred. Irradiation of ultraviolet light can be operated by high-pressure mercury lamp, xenon lamp, LED, etc. The amount of ultraviolet radiation is preferably 50mW/cm ² or more and 1000mW/cm ² or less. Further, according to the light amount of 50mJ / cm ² or more preferably, in particular, more preferably at 80mJ / cm ² or more, 200mJ / ² or more and still more preferably cm. In addition, the amount of illuminating light is preferably 10000 mJ/cm ² or less, particularly preferably 5000 mJ/cm ² or less, and even more preferably 2000 mJ/cm ² or less. On the other hand, electron beam irradiation can be performed using an electron beam accelerator, etc. The irradiation amount of the electron beam is preferably 10 krad or more and 1000 krad or less.

When the sheet material for workpiece processing of this embodiment has the adhesion force F0 in the aforementioned range, sufficient adhesion force can be exerted on the workpiece during the processing of the workpiece, and the movement of the workpiece or the workpiece after processing can be well suppressed/ Bad condition of shedding. In addition, when the adhesive layer is composed of an active energy ray-curable adhesive, and the ratio of the adhesive force F2/F0 is in the aforementioned range, even if the workpiece processing sheet is heated while the workpiece is pasted, then After the active energy rays are irradiated, the adhesion to the processed workpiece can be sufficiently reduced, so the processed workpiece can be picked up well. Therefore, the workpiece processing sheet of this embodiment can be used for applications such as exposing the workpiece processing sheet in a high temperature environment in a state where the workpiece or the processed workpiece is stuck on the workpiece processing sheet . In particular, the workpiece processing sheet of the present embodiment is suitable for dicing silicon wafers, etc. on the workpiece processing sheet, to heat the obtained wafers on the workpiece processing sheet, etc. the use of.

When the workpiece processing sheet of the present embodiment is used as a dicing sheet, and the wafer is attached to the workpiece processing sheet after dicing and then subjected to heat treatment, as the heating conditions, the heating temperature is for example It is preferably above 40°C, particularly preferably above 80°C, and even more preferably above 100°C. In addition, the heating temperature is preferably 150°C or less, particularly preferably 130°C or less, and even more preferably 120°C or less. Furthermore, the heating time is preferably 3 minutes or more, particularly 10 minutes or more, and more preferably 30 minutes or more. In addition, the heating time is preferably 60 minutes or less, particularly preferably 50 minutes or less, and even more preferably 40 minutes or less. The workpiece processing sheet of this embodiment can separate wafers well even when heated under the above conditions.

The above-described embodiments are described for easy understanding of the present invention, but the present invention is not limited by the description. Therefore, the purpose of each part disclosed in the above embodiment also includes all design changes and equivalents falling within the technical scope of the present invention.

For example, other layers may be provided between the substrate and the adhesive layer, or on the surface opposite to the adhesive layer of the substrate. Example

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

[Example 1] (1) Preparation of adhesive composition First, the acrylic copolymer obtained by copolymerizing 70 parts by mass of 2-ethylhexyl acrylate, 10 parts by mass of acryloylmorpholine and 20 parts by mass of 2-hydroxyethyl acrylate, and the acrylic copolymer The reaction of methacryloxyethyl isocyanate (MOI) with 90 mol% of 2-hydroxyethyl acrylate can obtain an active energy ray-curable polymer. The weight average molecular weight (Mw) of this active energy ray curable polymer was 830,000 when measured by the method described later.

100 parts by mass of the obtained active energy ray-curable polymer (converted to solid content, the same below) is used as a crosslinking agent containing hexamethylene diisocyanate-containing aliphatic isocyanate (manufactured by Japan Polyurethane Industry Co., Ltd., product name " Coronate HX") 1.2 parts by mass, photopolymerization initiator of 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propanyl)-benzyl]phenyl}-2 -Methyl-propan-1-one (manufactured by BASF, product name "Omnirad 127", 5% weight loss temperature: 220°C) 1.2 parts by mass are mixed in a solvent to obtain an adhesive composition. In addition, the 5% weight loss temperature of the photopolymerization initiator was determined by using a differential thermal-thermogravimetric simultaneous analysis device (manufactured by SHIMADZU, product name "DTG-60"), and the temperature was increased from room temperature at a temperature increase rate of 5°C/min. Heat to 300°C for measurement.

(2) Formation of adhesive layer Coat the release surface of a release sheet (manufactured by LINTEC Corporation, product name "SP-PET381031") with a silicone release agent layer formed on one side of a polyethylene terephthalate film with a thickness of 38 μm. The above-mentioned adhesive composition is heated and dried, and then aged for 7 days under the conditions of 23°C and 50% RH to form an adhesive layer with a thickness of 5 μm on the release sheet.

(3) Production of sheets for workpiece processing Take the adhesive layer formed in the above step (2) on the opposite side of the release sheet, and the base material is a 75μm heat-resistant polyester film (manufactured by Kurabo, product name "Torcena") Attach one side of the sheet to obtain a sheet for workpiece processing.

Among them, the aforementioned weight average molecular weight (Mw) is measured (GPC measurement) using colloidal filtration chromatography (GPC) and then converted into the weight average molecular weight of standard polystyrene.

[Examples 2 to 8 and Comparative Examples 1 to 4] Except that the composition and weight average molecular weight of the acrylic copolymer were changed as shown in Table 1, and the composition of the adhesive composition was changed as shown in Table 2, the workpiece processing sheet was produced as in Example 1.

[Test Example 1] (Measurement of the glass transition temperature of the adhesive) Laminating multiple layers Using the adhesive layers of the workpiece processing sheets produced in the examples and comparative examples, a laminate of an adhesive layer with a thickness of 800 μm was produced. Then, a circle with a diameter of 10 mm was cut out from the laminate of the adhesive layer to obtain a sample for measurement. Then use a dynamic viscoelasticity measuring device (manufactured by TA Instruments, product name "ARES") for the sample used for the measurement at a frequency of 1 Hz, a measurement temperature range of -50 to 150°C, and a temperature rise rate of 3°C/min. Measure tanδ, and take the temperature of its highest peak as Tg. The results are shown in Table 3.

[Test Example 2] (Measurement of Adhesion) The workpiece processing sheets manufactured in the Examples and Comparative Examples were cut into strips with a width of 25 mm. Then peel off the strip from the obtained strip-shaped workpiece processing sheet to expose the adhesive surface of the adhesive layer facing the mirror surface of the mirror-finished silicon wafer at a temperature of 23°C and a relative humidity of 50%. In the environment, it was pasted with a 2kg rubber roller, and after standing for 20 minutes, it was used as a measurement sample.

Then, using a universal tensile testing machine (manufactured by ORIENTEC, the product name is "TENSILON UTM-4-100"), the obtained measurement sample is peeled from the silicon wafer at a peeling speed of 300mm/min and a peeling angle of 180° The sheet material used for workpiece processing is measured by the 180° tensile peeling method according to JIS Z0237:2009 to measure the adhesion force (mN/25mm) to the silicon wafer. And the adhesive force obtained by this is the adhesive force F0, and the results are shown in Table 3.

After that, the sample for measurement obtained as described above was heated in an oven at 150°C for 1 hour. For the heated test sample, the adhesion to the silicon wafer (mN/25mm) was measured as above. Taking the adhesive force obtained in this way as the adhesive force F1, the results are shown in Table 3.

Then, the sample for measurement obtained as described above was heated in an oven at 150°C for 1 hour. In addition, the adhesive layer was irradiated with ultraviolet rays under the following conditions via the base material. For this measurement sample, the adhesive force (mN/25mm) to the silicon wafer was measured as described above. Taking the adhesive force obtained in this way as the adhesive force F2, the results are shown in Table 3. >Ultraviolet radiation conditions> ・Using high-pressure mercury lamp ・Illumination 230mW/cm ² , Illumination 190mJ/cm ²・UV illuminance/illumination meter using "UVPF-A1" manufactured by EYE GRAPHICS

At the same time, calculate the ratio of the adhesion force F2 to the adhesion force F0 (F2/F0) and the ratio of the adhesion force F0 to the adhesion force F1 (F0/F1) using the three types of adhesion obtained above. The results are shown in Table 3.

[Test Example 3] (Measurement of Young's Coefficient of Adhesive) For each of the Examples and Comparative Examples, a plurality of laminates of the adhesive layer and the release sheet produced in the above step (2) of Example 1 were prepared. Then, a predetermined number of adhesive layers were laminated on the laminate to produce an adhesive layer sample for measurement composed of an adhesive layer with a thickness of 200 μm.

The obtained adhesive layer sample for measurement was pulled using a universal tensile tester (manufactured by Shimadzu Corporation, product name "AUTOGRAPH AG-1S") at a temperature of 23°C with a distance between chucks of 30 mm and a speed of 200 mm/min. Stretch, and then calculate the Young’s coefficient (MPa) from the resulting stress-deformation curve. The result obtained in this way is the Young's coefficient E0, and the result is shown in Table 3.

In addition, the adhesive layer sample for measurement obtained above was heated at 150°C for 1 hour in an oven. For the heated adhesive layer sample for measurement, the Young's coefficient (MPa) is calculated as described above. The result obtained in this way is the Young's coefficient E1, and the result is shown in Table 3.

In addition, the adhesive layer sample for measurement obtained as described above was heated in an oven at 150°C for 1 hour. At the same time, the heated adhesive layer sample for measurement was irradiated with ultraviolet rays under the following conditions. For the sample of the adhesive layer for measurement, the Young's coefficient (MPa) was determined as described above. The result obtained in this way is Young's coefficient E2, and the result is shown in Table 3. >Ultraviolet radiation conditions> ・Using a high-pressure mercury lamp ・Illumination 230mW/cm ² , Illumination 580mJ/cm ²・UV illuminance/illumination meter using "UVPF-A1" manufactured by EYE GRAPHICS

Furthermore, the ratio of Young's coefficient E1 to Young's coefficient E0 (E1/E0) and the ratio of Young's coefficient E2 to Young's coefficient E1 (E2/E1) are calculated using the three Young's coefficients obtained above. The results are shown in Table 3.

[Test Example 4] (Evaluation of initial adhesion) Peel off the release sheet from the workpiece processing sheet manufactured in the Examples and Comparative Examples, and then use a tape sticking machine (manufactured by LINTEC, product name "Adwill RAD 2500m/12") on the exposed surface of the exposed adhesive layer , Paste on the polished surface of a 6-inch silicon wafer (thickness: 350 μm) polished by #2000. Then, using a dicing machine (manufactured by DISCO, the product name is "DFD-6362"), under the following cutting conditions, the cutting surface is supplied with running water and cut from the side of the 6-inch silicon wafer.

>Cutting conditions> ・Cutting machine: DFD-6362 made by DISCO ・Blade: made by DISCO, NBC-2H 2050 27HECC ・Blade width: 0.025 to 0.030mm ・The amount of tip exposure: 0.640 to 0.760mm ・Blade speed: 50000rpm ・Cutting speed: 20mm/sec ・Cutting depth: 20μm from the surface of the adhesive layer side of the workpiece processing sheet to the base material ・Flow water supply: 1.0L/min ・Water temperature: room temperature ・Cutting size: 2mm×2mm

Then, visually observe the workpiece processing sheet on which the wafer obtained through the cutting step is attached, calculate the number of wafers that fall off the workpiece processing sheet in the cutting step, and divide the number by the number of cuts in the cutting step, The wafer detachment rate (unit: %) can be calculated. Based on the results of this calculation, evaluate the initial adhesion according to the following criteria. The evaluation results are shown in Table 3. ○ : The wafer detachment rate is less than 10%. ╳ : The wafer detachment rate is more than 10%.

[Test Example 5] (Assessment of suitability of crystal selection) Using the workpiece processing sheets manufactured in the Examples and Comparative Examples, cutting was performed as in Test Example 4, except that the cutting size was changed to 10 mm×10 mm.

After the cutting is completed, the wafer-bearing workpiece processing sheet is placed in the oven. Heat at 150°C for 1 hour. Then, the adhesive layer in the sheet for workpiece processing was irradiated with ultraviolet rays under the following conditions through the substrate. >Ultraviolet radiation conditions> ・Using high-pressure mercury lamp ・Illumination 230mW/cm ² , Illumination 190mJ/cm ²・UV illuminance/illumination meter using "UVPF-A1" manufactured by EYE GRAPHICS

Pick up 100 wafers from the workpiece processing sheet after ultraviolet radiation, and evaluate the suitability of the wafers according to the following standards. The results are shown in Table 3. ◎: Among 100, the number of wafers with good crystal picking is more than 95. ○ : Among 100, the number of wafers that can obtain good crystals is less than 95 or more than 80. ╳ : Among 100, the number of wafers that can be obtained well is less than 80.

In addition, the abbreviations etc. described in Table 1 and Table 2 are detailed as follows. 〔Composition of active energy ray curable polymer〕 2EHA: 2-ethylhexyl acrylate BA: Butyl acrylate ACMO: Acrylic morpholine (SP value: 10.1, glass transition temperature: 145°C) MMA: methyl methacrylate (SP value: 9.5, glass transition temperature: 105°C) IBXA: Isocamyl acrylate (SP value: 10.2, glass transition temperature: 94°C) HEA: 2-hydroxyethyl acrylate MOI: Methacryloxyethyl isocyanate 〔Photopolymerization initiator〕 Omnirad 127: 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propanyl)-benzyl]phenyl}-2-methyl-propan-1-one (BASF Manufactured by the company, the product name is "Omnirad 127", 5% weight loss temperature: 220℃) Omnirad TPO: Oxidized-2,4,6-trimethylbenzyldiphenylphosphine (manufactured by BASF, product name "Omnirad TPO", 5% weight loss temperature: 225°C)

[Table 1] Composition of active energy ray hardening polymer Weight average molecular weight of active energy ray curable polymer Composition of acrylic copolymer (parts by mass) MOI (Mole% relative to HEA mole number) 2EHA BA ACMO MMA IBXA HEA Example 1 70 ─ 10 ─ ─ 20 90 830,000 Example 2 80 ─ 10 ─ ─ 10 90 950,000 Example 3 60 ─ 10 ─ ─ 30 70 860,000 Example 4 60 ─ 10 ─ ─ 30 80 850,000 Example 5 60 ─ 10 ─ ─ 30 90 800 000 Example 6 60 ─ ─ 10 ─ 30 90 820,000 Example 7 60 ─ ─ ─ 10 30 90 830,000 Example 8 70 ─ 10 ─ ─ 20 90 830,000 Comparative example 1 ─ 90 ─ ─ ─ 10 90 800 000 Comparative example 2 ─ 70 ─ ─ ─ 30 90 800 000 Comparative example 3 70 ─ ─ ─ ─ 30 90 900,000 Comparative example 4 90 ─ ─ ─ ─ 10 90 1000000

[Table 2] The composition of the adhesive composition (mass part, solid content conversion value) Active energy ray curable polymer Crosslinking agent Photopolymerization initiator species content Example 1 100 1.2 Omnirad 127 1.2 Example 2 100 0.6 Omnirad 127 1.2 Example 3 100 5.5 Omnirad 127 1.2 Example 4 100 3.7 Omnirad 127 1.2 Example 5 100 1.8 Omnirad 127 1.2 Example 6 100 1.8 Omnirad 127 1.2 Example 7 100 1.8 Omnirad 127 1.2 Example 8 100 1.2 Omnirad TPO 1.2 Comparative example 1 100 0.6 Omnirad 127 1.2 Comparative example 2 100 1.7 Omnirad 127 1.2 Comparative example 3 100 1.7 Omnirad 127 1.2 Comparative example 4 100 0.6 Omnirad 127 1.2

[table 3] Tg of adhesive (℃) Adhesion (mN/25mm) Adhesion ratio Young's coefficient (MPa) Young's coefficient ratio Evaluation of initial adhesion Evaluation of suitability of crystal taking F0 F1 F2 F2/F0 F0/F1 E0 E1 E2 E1/E0 E2/E1 Example 1 -9 1570 3600 110 0.07 2.3 3.5 5.0 90.0 1.43 18.00 ○ ○ Example 2 -9 1400 2400 100 0.07 1.7 3.1 3.2 13.1 1.03 4.05 ○ ○ Example 3 -9 950 3000 120 0.13 3.2 12.6 15.0 130.0 1.19 8.67 ○ ○ Example 4 -9 1200 3400 90 0.08 2.8 7.3 10.0 140.0 1.37 14.00 ○ ○ Example 5 -9 2100 3600 75 0.04 1.7 2.9 7.8 150.0 2.67 19.20 ○ ◎ Example 6 -11 670 1200 75 0.11 1.8 2.8 7.4 148.5 2.64 20.07 ○ ◎ Example 7 1 1700 3000 75 0.04 1.8 2.7 7.1 145.5 2.63 20.49 ○ ◎ Example 8 -9 1590 3500 120 0.08 2.2 3.6 4.8 85.0 1.33 17.71 ○ ◎ Comparative example 1 -10 400 2200 750 1.88 5.5 1.6 1.2 14.3 0.71 12.25 ╳ ╳ Comparative example 2 -10 350 2000 700 2.00 5.7 2.2 5.3 68.0 2.41 12.83 ╳ ╳ Comparative example 3 -11 450 1000 430 0.96 2.2 2.0 5.2 129.3 2.56 25.06 ╳ ╳ Comparative example 4 -11 400 600 500 1.25 1.5 1.4 1.3 17.0 0.93 12.81 ╳ ╳

It can be seen from Table 3 that the sheet for workpiece processing obtained in the examples has excellent initial adhesion and can hold the workpiece on the sheet well during processing of the workpiece. In addition, the sheet material for workpiece processing obtained in the examples has excellent suitability for crystal extraction, that is, when crystals are acquired, it is shown that the adhesion to the processed workpiece can be reduced well. [Possibility of Industrial Use]

Therefore, the sheet for workpiece processing of the present invention can be suitably used for cutting.

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Claims (6)

A sheet for processing a workpiece, which has a substrate and an adhesive layer laminated on one surface of the aforementioned substrate, and is characterized in that: The aforementioned adhesive layer is composed of an active energy ray-curable adhesive, The adhesion force of the aforementioned workpiece processing sheet to the silicon wafer is F0, The laminated body formed by bonding the aforementioned workpiece processing sheet to a silicon wafer is heated at 150°C for 1 hour and then irradiated with active energy rays to the adhesive layer constituting the aforementioned laminated body, and the aforementioned workpiece processing sheet When the adhesive force of the material to the silicon wafer is F2, The aforementioned adhesion force F0 is 600mN/25mm or more and 20000mN/25mm or less, The ratio of the aforementioned adhesion force F2 to the aforementioned adhesion force F0 (F2/F0) is 0.66 or less. The sheet for workpiece processing according to claim 1, wherein after the sheet for workpiece processing is heated at 150°C for 1 hour, the Young's coefficient of the adhesive layer at 23°C is E1, After the sheet for workpiece processing is heated at 150°C for 1 hour, and then the adhesive layer constituting the sheet for workpiece processing is irradiated with active energy rays, when the Young's coefficient of the adhesive layer at 23°C is E2 , The ratio (E2/E1) of the aforementioned Young's coefficient E2 to the aforementioned Young's coefficient E1 is 13 or more. The sheet for workpiece processing according to claim 1, wherein the Young's coefficient of the adhesive layer at 23°C in the sheet for workpiece processing is E0, After the aforementioned workpiece processing sheet is heated at 150°C for 1 hour, when the Young's coefficient of the aforementioned adhesive layer at 23°C is E1, The ratio (E1/E0) of the aforementioned Young's coefficient E1 to the aforementioned Young's coefficient E0 is 2.0 or more. A sheet for processing a workpiece, which has a substrate and an adhesive layer laminated on one surface of the aforementioned substrate, and is characterized in that: The aforementioned adhesive layer is composed of an active energy ray-curable adhesive, The glass transition temperature of the active energy ray curable adhesive is above -50°C and below 10°C, The aforementioned active energy ray-curable adhesive is an acrylic copolymer containing a monomer having a polar group as a constituent monomer. The workpiece processing sheet according to claim 4, wherein the acrylic copolymer has a functional group having active energy ray curability introduced into the side chain. The sheet for processing a workpiece according to any one of claims 1 to 5, which is a cut sheet.