KR20210088525A - Sheet for work processing - Google Patents

Abstract

A sheet for work processing comprising a base material and a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive, the adhesive force of the sheet for work processing to a silicon wafer is F0, and the sheet for work processing is adhered to a silicon wafer After heating the combined laminate at 150° C. for 1 hour, irradiating active energy rays to the pressure-sensitive adhesive layer constituting the laminate. When the adhesive force of the sheet for work processing to the silicon wafer is F2, the adhesive force F0 is A sheet for processing a workpiece, wherein the sheet is 600 mN/25 mm or more and 20000 mN/25 mm or less, and the ratio of the adhesive force F2 to the adhesive force F0 (F2/F0) is 0.66 or less. According to such a work-processing sheet, after heat processing, while exhibiting sufficient adhesive force with respect to the said work piece at the time of work processing, the workpiece|work after a process can be separated favorably.

Description

Sheet for work processing

This invention relates to the sheet|seat for work processing which can be used suitably for dicing.

Semiconductor wafers such as silicon and gallium arsenide and various packages (hereinafter, these may be collectively referred to as “workpieces”) are manufactured in a large-diameter state, and these are small element pieces (hereinafter referred to as “chips”). After being cut and separated (dicing) and individually separated (picked up), it is transferred to the next step, the mounting process. At this time, the workpiece|work, such as a semiconductor wafer, is provided to each process of dicing, washing|cleaning, drying, expansion, pick-up, and mounting in the state stuck to the sheet|seat for a workpiece|work provided with a base material and an adhesive layer. Such a sheet for work processing is required to have the ability to easily separate the work after processing from the sheet while maintaining the work well on the sheet during processing.

The chip obtained as described above may be subjected to a heat treatment thereafter. For example, processing such as vapor deposition, sputtering, and baking for dehumidification may be performed on the chip. In addition, when the chip is supposed to be used in a high-temperature environment, a heating test is also performed to confirm reliability in such an environment. Usually, such heat processing is performed in the state which mounted the obtained chip|tip on the heating tray.

In recent years, performing the heat processing of the above-mentioned chip|tip on the sheet|seat for a workpiece|work processing is examined. That is, after dicing a workpiece|work on the sheet|seat for a workpiece|work processing, without transferring the obtained chip|tip to a heating tray, heat-processing with respect to a chip|tip while being mounted on the sheet|seat for a workpiece|work processing is examined. In this case, the process can be simplified.

Patent Documents 1 to 3 disclose the pressure-sensitive adhesive sheet supposing that the above-described heat treatment is performed. In particular, the pressure-sensitive adhesive sheet disclosed in Patent Document 1 has a base layer and a pressure-sensitive adhesive layer composed of a radiation-curing pressure-sensitive adhesive, and the pressure-sensitive adhesive layer has an adhesive force to SUS304 of 0.5 N/20 mm or more after bonding the resin. It hardens by the stimulus received until the time of completion of the sealing process, and it becomes a layer from which the peeling force with respect to a package becomes 2.0 N/20 mm or less. Moreover, in the adhesive sheet disclosed by patent document 2, an adhesive layer is what was formed from the adhesive composition containing a predetermined|prescribed adhesive component and a predetermined|prescribed tetrazole compound. Further, in the pressure-sensitive adhesive sheet disclosed in Patent Document 3, a pressure-sensitive adhesive layer made of a material for forming a pressure-sensitive adhesive layer containing a predetermined acrylic polymer, an energy-beam polymerizable oligomer, a predetermined polymerization initiator, and a crosslinking agent is formed on a heat-resistant substrate. have.

Patent Document 1: Japanese Patent No. 5144634 Patent Document 2: Japanese Patent No. 5555578 Patent Document 3: Japanese Patent No. 5565173

However, when the heat treatment of the chips as described above is performed on a conventional sheet for work processing, the adhesive strength of the sheet for work processing to the chips is improved by heating, so that the chips can be picked up from the sheet satisfactorily after the heat treatment. There was a problem that couldn't be done. Even if it used the adhesive sheet which has predetermined heat resistance disclosed by patent documents 1 - 3, such a problem could not fully be solved.

The present invention is made in view of such a reality, and it is to provide a sheet for work processing that can satisfactorily separate the work after processing after heat treatment while exhibiting sufficient adhesive force to the work during machining of the work. The purpose.

In order to achieve the above object, the first present 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 adhesive force of the sheet for work processing to a silicon wafer is F0, and after heating a laminate formed by bonding the sheet for work processing to a silicon wafer at 150° C. for 1 hour, the pressure-sensitive adhesive layer constituting the laminate When the adhesive force of the sheet for work processing to the silicon wafer is F2 after further irradiation with active energy rays, the adhesive force F0 is 600 mN/25 mm or more and 20000 mN/25 mm or less, and the adhesive force with respect to the adhesive force F0 The ratio of F2 (F2/F0) is 0.66 or less, The sheet|seat for work processing characterized by the above-mentioned (Invention 1) is provided.

In the sheet for work processing according to the invention (invention 1), when the adhesive force F0 is within the above range, sufficient adhesive force can be exhibited with respect to the workpiece during processing of the work. On the other hand, the pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive, and the above-described adhesive force ratio (F2/F0) is within the above range, and the workpiece processing sheet is heated in a state in which the processed workpiece is stuck. Even in this case, by irradiating an active energy ray after that, the adhesive force to the workpiece after processing can be sufficiently reduced, whereby the workpiece after processing can be separated satisfactorily.

In the invention (invention 1), after heating the sheet for work processing at 150° C. for 1 hour, the Young’s modulus at 23° C. of the pressure-sensitive adhesive layer is E1, and after heating the sheet for work processing at 150° C. for 1 hour, After the pressure-sensitive adhesive layer constituting the sheet for work processing is further irradiated with active energy rays, when the Young's modulus at 23°C of the pressure-sensitive adhesive layer is E2, the ratio of the Young's modulus E2 to the Young's modulus E1 (E2/E1) ) is preferably 13 or more (Invention 2).

In the above inventions (Inventions 1 and 2), in the sheet for work processing, the Young's modulus at 23° C. of the pressure-sensitive adhesive layer is E0, and after heating the sheet for work processing at 150° C. for 1 hour, at 23° C. of the pressure-sensitive adhesive layer When the Young's modulus of is E1, the ratio of the Young's modulus E1 to the Young's modulus E0 (E1/E0) is preferably 2.0 or more (Invention 3).

A second aspect of the present 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, and the active energy ray-curable adhesive has a glass transition temperature of -50 ° C. or more and 10 ° C. or less, and the active energy ray-curable pressure-sensitive adhesive includes an acrylic copolymer comprising a monomer having a polar group as a constituent monomer. Invention 4).

In the invention (invention 4), the acrylic copolymer preferably introduces a functional group having active energy ray curability into a side chain (invention 5).

In the said invention (Inventions 1-5), it is preferable that it is a dicing sheet (Invention 6).

The sheet for processing a workpiece according to the present invention can satisfactorily separate the workpiece after processing after heat treatment while exhibiting sufficient adhesive force to the workpiece during processing of the workpiece.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described.

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. In addition, the said adhesive layer is comprised by the active-energy-ray-curable adhesive.

1.Physical properties of sheet for workpiece processing

(1) Adhesion

In the sheet for work processing according to the present embodiment, when the adhesive force of the sheet for work processing to a silicon wafer is F0, the adhesive force F0 is preferably 600 mN/25 mm or more, and particularly preferably 900 mN/25 mm or more. and 1200 mN/25 mm or more is preferable. Moreover, it is preferable that adhesive force F0 is 20000 mN/25 mm or less, It is especially preferable that it is 5000 mN/25 mm or less, It is also preferable that it is 3000 mN/25 mm or less. In addition, the said adhesive force F0 means the initial adhesive force measured with respect to the sheet|seat for work processing which has not performed the process, such as heating or active energy ray irradiation, which are mentioned later.

In the sheet for work processing which concerns on this embodiment, when adhesive force F0 is the said range, it becomes possible to hold|maintain a work favorably on the sheet|seat for a work process. For this reason, at the time of processing of a workpiece|work, even when an impact by processing arises, for example, it becomes possible to suppress favorably the movement and drop-off|omission of the workpiece|work after processing. In particular, when the adhesive force F0 is 600 mN/25 mm or more, it becomes easy to hold the workpiece favorably at the time of processing. On the other hand, when the adhesive force F0 is 20000 mN/25 mm or less and the sheet for processing a workpiece is irradiated with an active energy ray, which will be described later, it is easy to sufficiently reduce the adhesive strength to the workpiece after processing. It becomes easy to separate from the sheet|seat for a process.

In the sheet for work processing according to the present embodiment, after heating a laminate formed by bonding the sheet for work processing to a silicon wafer at 150° C. for 1 hour, the pressure-sensitive adhesive layer constituting the laminate is further irradiated with active energy rays When the adhesive force of the sheet for work processing to the silicon wafer is F2, the ratio (F2/F0) of the adhesive force F2 to the adhesive force F0 described above is preferably 0.66 or less, particularly preferably 0.2 or less, and 0.15 or less desirable. When the ratio (F2/F0) is 0.66 or less, it is easy to achieve satisfactory compatibility between holding of the workpiece during processing and separation of the workpiece after processing after irradiation with an active energy ray. In particular, even when the sheet for work processing is exposed to heat treatment in a state in which the workpiece after processing is affixed on the sheet for processing the workpiece, the workpiece after processing can be easily separated from the sheet for processing the workpiece. Moreover, although it does not specifically limit about the lower limit of the said ratio (F2/F0), For example, 0.01 or more may be sufficient.

In the sheet for work processing according to the present embodiment, the adhesive force F2 described above is preferably 1000 mN/25 mm or less, particularly preferably 500 mN/25 mm or less, and further preferably 150 mN/25 mm or less. Moreover, it is preferable that adhesive force F2 is 30 mN/25 mm or more. When adhesive force F2 is the said range, it becomes easy to adjust ratio (F2/F0) to the above-mentioned range.

In the sheet for work processing according to this embodiment, when the adhesive force of the sheet for work processing to the silicon wafer is F1 after heating a laminate formed by bonding the sheet for work processing to a silicon wafer at 150° C. for 1 hour, the adhesive force F1 It is preferably 1000 mN/25 mm or more, and particularly preferably 2300 mN/25 mm or more. Moreover, it is preferable that the adhesive force F1 is 5000 mN/25 mm or less. When adhesive force F1 is the said range, it becomes easy to adjust ratio (F2/F0) to the above-mentioned range.

In addition, the detail of each measuring method of the adhesive force F0, F1, and F2 mentioned above is as having described in the test example mentioned later.

(2) Young's modulus

In the sheet for work processing according to the present embodiment, after the sheet for work processing is heated at 150° C. for 1 hour, the Young’s modulus at 23° C. of the pressure-sensitive adhesive layer is set to E1, and the sheet for work processing is heated at 150° C. for 1 hour, Ratio of the Young's modulus E2 to the Young's modulus E1 (E2/E1) when the Young's modulus at 23°C of the pressure-sensitive adhesive layer is set to E2 after the pressure-sensitive adhesive layer constituting the sheet for work processing is further irradiated with active energy rays is preferably 13 or more, particularly preferably 15 or more, and more preferably 18 or more.

As mentioned above, the adhesive layer in this embodiment is comprised from an active energy ray-curable adhesive. Generally, the component for achieving active energy ray sclerosis|hardenability which exists in an active energy ray-curable adhesive may perform predetermined reaction by heating, and it originates in this and hardening of an adhesive may advance. For example, when the said component is an acryloyl group, the carbon-carbon double bond in this acryloyl group may be cleaved by heating, and a polymerization reaction may advance. Thus, when reaction of the said component advances by heating, even if it irradiates an active energy ray after that, further hardening of an adhesive layer will not advance favorably. However, in the sheet for work processing according to the present embodiment, if the ratio (E2/E1) is within the above range, the adhesive force is easily lowered favorably by irradiation with an active energy ray even after heat treatment. For this reason, before irradiation of an active energy ray, the unintentional drop-off|omission of the workpiece|work after a process, etc. can be suppressed effectively.

Moreover, it does not specifically limit about the upper limit of the said ratio (E2/E1), For example, 25 or less may be sufficient.

In the sheet for work processing according to the present embodiment, when the Young's modulus at 23° C. of the pressure-sensitive adhesive layer in the sheet for work processing is E0, the ratio (E1/E0) of the Young's modulus E1 to the Young's modulus E0 (E1/E0) is 2.0 or more It is preferable that it is especially preferable that it is 2.3 or more, and it is also preferable that it is 2.6 or more. In addition, the said Young's modulus E0 means the initial Young's modulus measured with respect to the adhesive layer to which processing, such as heating or active energy ray irradiation, was not performed.

Generally, when an adhesive is heated, it softens and there exists a tendency for adhesiveness to to-be-adhered body to increase. However, in the sheet for work processing according to the present embodiment, if the ratio (E1/E0) is within the above range, softening of the pressure-sensitive adhesive due to heating becomes difficult to occur, so that excessive improvement in adhesiveness due to heat treatment can be effectively suppressed do. As a result, after irradiating an active energy ray with respect to an adhesive layer, it becomes easy to isolate|separate the workpiece|work after a process favorably.

Moreover, it does not specifically limit about the upper limit of the said ratio (E1/E0), For example, 3.5 or less may be sufficient.

In the sheet for work processing according to the present embodiment, the Young's modulus E0 described above is preferably 2.0 MPa or more, particularly preferably 2.3 MPa or more, and more preferably 2.5 MPa or more. The Young's modulus E0 is preferably 15 MPa or less, particularly preferably 10 MPa or less, and more preferably 5 MPa or less. When the Young's modulus E0 is within the above range, it is easy to adjust the ratio (E1/E0) to the above range.

In the sheet for work processing according to the present embodiment, the Young's modulus E1 described above is preferably 5.0 MPa or more, particularly preferably 6.0 MPa or more, and more preferably 7.0 MPa or more. The Young's modulus E1 is preferably 100 MPa or less, particularly preferably 50 MPa or less, and more preferably 10 MPa or less. When the Young's modulus E1 is within the above range, it is easy to adjust the ratio (E2/E1) and the ratio (E1/E0) to the above-mentioned ranges, respectively.

In the sheet for work processing according to the present embodiment, the Young's modulus E2 described above is preferably 100 MPa or more, particularly preferably 130 MPa or more, and further preferably 140 MPa or more. The Young's modulus E2 is preferably 300 MPa or less, particularly preferably 250 MPa or less, and more preferably 200 MPa or less. When the Young's modulus E2 is within the above range, it is easy to adjust the ratio (E2/E1) to the above range.

In addition, the detail of each measuring method of the above-mentioned Young's modulus E0, E1, and E2 is as having described in the test example mentioned later.

2. Structural member of sheet for workpiece processing

(1) description

In the sheet for work processing according to the present embodiment, the substrate exhibits a desired function in the step of using the sheet for work processing, and preferably exhibits good permeability to the active energy ray irradiated for curing the pressure-sensitive adhesive layer. At the same time, it is not particularly limited as long as it has predetermined heat resistance.

For example, it is preferable that the base material is a resin film mainly made of a resin-based material, and specific examples thereof include an ethylene-vinyl acetate copolymer film; ethylene-based copolymer films such as an ethylene-(meth)acrylic acid copolymer film, an ethylene-(meth)acrylic acid methyl copolymer film, and other ethylene-(meth)acrylic acid ester copolymer films; Polyolefin films, such as a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, an ethylene norbornene copolymer film, a norbornene resin film, and a cycloolefin resin film; polyvinyl chloride-based films such as polyvinyl chloride films and vinyl chloride copolymer films; polyester films such as polyethylene terephthalate film, polybutylene terephthalate film, polycyclohexylene dimethylene terephthalate, and polyethylene naphthalate; (meth)acrylic acid ester copolymer film; polyurethane film; polyimide film; polystyrene film; polycarbonate film; fluororesin film; A polyphenylene sulfide film etc. are mentioned. Examples of the polyethylene film include a low-density polyethylene (LDPE) film, a linear low-density polyethylene (LLDPE) film, and a high-density polyethylene (HDPE) film. In addition, modified films such as these crosslinked films and ionomer films are also used. Moreover, the laminated|multilayer film by which the above-mentioned film is laminated|stacked may be sufficient as a base material. In this laminated|multilayer film, the same type may be sufficient as the material which comprises each layer, and different types may be sufficient as it. As the substrate, from the viewpoint of excellent active energy ray permeability and heat resistance among the above films, an annealed polyester film, a polyester film having heat resistance, a polycarbonate film, a polyphenylene sulfide film, a cycloolefin resin film It is preferable to use 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 a flame retardant, a plasticizer, an antistatic agent, a lubricant, an antioxidant, a colorant, an infrared absorber, an ultraviolet absorber, and an ion trapping agent. Although it does not specifically limit as content of such an additive, 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 treatment such as a primer treatment, a corona treatment, a plasma treatment, or the like, 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 by which the sheet|seat for work processing is used, Usually, it is preferable that it is 20 micrometers or more, and it is especially preferable that it is 25 micrometers or more. Moreover, it is preferable that the said thickness is normally 450 micrometers or less, and it is especially preferable that it is 300 micrometers or less.

(2) adhesive layer

The sheet for work processing which concerns on this embodiment WHEREIN: The adhesive layer is comprised from an active energy ray-curable adhesive. Since the pressure-sensitive adhesive layer is constituted by an active energy ray-curable pressure-sensitive adhesive, the pressure-sensitive adhesive layer can be cured by irradiation with an active energy ray and the adhesive force of the sheet for work processing to an adherend can be reduced. For this reason, it becomes possible to isolate|separate the workpiece|work after a process from the sheet|seat for a workpiece|work process easily.

Moreover, it is preferable that the adhesive layer in this embodiment can achieve the adhesive force mentioned above. From this viewpoint, as for the adhesive layer in this embodiment, while the glass transition temperature of the active energy ray-curable adhesive which comprises the said adhesive layer is -50 degreeC or more and 10 degrees C or less, an active energy ray-curable adhesive is a monomer which has a polar group. It is preferable to include an acrylic copolymer containing as a constituent monomer. By providing the adhesive layer comprised from such an active energy ray-curable adhesive, the sheet|seat for a work process becomes easy to achieve the adhesive force mentioned above.

From a viewpoint that the sheet|seat for a work process more easily achieves the adhesive force mentioned above, it is preferable that it is especially preferable that the said glass transition temperature is -20 degreeC or more, and it is further more preferable that it is -15 degreeC or more. Moreover, it is preferable that it is especially 5.0 degreeC or less, and, as for the said glass transition temperature, it is also preferable that it is 3.0 degrees C or less from a similar viewpoint. In addition, the detail of the measuring method of the said glass transition temperature is as having described in the test example mentioned later.

The active energy ray-curable pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer may contain a polymer having active energy ray curability as a main component, an active energy ray non-curable polymer (a polymer that does not have active energy ray curability) and at least one active energy The main component may be a mixture of monomers and/or oligomers having a precurable group.

First, the case where an active energy ray-curable adhesive has a polymer which has active energy ray sclerosis|hardenability as a main component is demonstrated below.

The polymer having active energy ray curability is a (meth)acrylic acid ester (co)polymer (A) into which a functional group having active energy ray curability (active energy ray curable group) is introduced into a side chain (hereinafter referred to as "active energy ray curable polymer (A)" )" is preferable. The active energy ray-curable polymer (A) is preferably obtained by reacting an acrylic copolymer (a1) having a functional group-containing monomer unit with an unsaturated group-containing compound (a2) having a functional group bonded to the functional group.

As the functional group-containing monomer described above, a monomer having a polymerizable double bond and a functional group such as a hydroxyl group, a carboxy group, an amino group, an amide group, a benzyl group, and a glycidyl group in a molecule is preferable, and among these, a monomer containing a hydroxyl group as a functional group (a hydroxyl group-containing monomer) is preferably used.

As said hydroxyl-containing monomer, (meth)acrylic acid 2-hydroxyethyl, (meth)acrylic acid 2-hydroxypropyl, (meth)acrylic acid 3-hydroxypropyl, (meth)acrylic acid 2-hydroxybutyl is, for example, , (meth)acrylic acid 3-hydroxybutyl, (meth)acrylic acid 4-hydroxybutyl, etc. are mentioned, Among these, it is preferable to use 2-hydroxyethyl acrylate. In addition, these are 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 may be used independently and may be used in combination of 2 or more type.

Examples of the amino group-containing monomer or amide group-containing monomer include aminoethyl (meth)acrylate and n-butylaminoethyl (meth)acrylate. These may be used independently and may be used in combination of 2 or more type.

The acrylic copolymer (a1) preferably contains 1 mass% or more of the structural unit derived from the functional group-containing monomer, particularly preferably 5 mass% or more, and preferably contains 10 mass% or more. . Moreover, it is preferable that the acrylic copolymer (a1) contains 35 mass % or less of the structural unit derived from the said functional group containing monomer, and it is especially preferable to contain 30 mass % or less. When an acryl-type copolymer (a1) contains a functional group containing monomer in the said range, it becomes easy to form a desired active energy ray-curable polymer (A).

As described above, the acrylic copolymer (a1) preferably contains a monomer having a polar group (a polar group-containing monomer) as a monomer unit constituting the polymer. For this reason, the polarity of the active energy ray-curable adhesive obtained improves, and it becomes easy to achieve the adhesive force mentioned above.

Examples of the polar group-containing monomer include acryloyl morpholine, isobornyl acrylate, methyl methacrylate, vinyl acetate, benzyl acrylate, glycidyl methacrylate, and the like, and among these, particularly, acryloyl morpholine or Preference is given to using isobornyl acrylate.

The acrylic copolymer (a1) preferably contains 3.0 mass % or more of the structural unit derived from the polar group-containing monomer, particularly preferably 5.0 mass % or more, and further preferably contains 8.0 mass % or more. . Moreover, it is preferable that the acrylic copolymer (a1) contains 12.0 mass % or less of the structural unit derived from the said polar group containing monomer. When the acrylic copolymer (a1) contains the polar group-containing monomer in the above range, the polarity of the obtained active energy ray-curable pressure-sensitive adhesive can be effectively improved, thereby making it easy to achieve the above-described adhesive force.

Moreover, it is also preferable that the acrylic copolymer (a1) contains the monomer (Tg adjustment monomer) for adjusting the glass transition temperature (Tg) of an active energy ray-curable adhesive as a monomer unit which comprises a polymer. For this reason, the active-energy-ray-curable adhesive obtained becomes easy to have the above-mentioned glass transition temperature (Tg). As an example of a preferable monomer which also serves as a Tg-adjusting monomer, the thing mentioned above as an example of a polar group containing monomer is mentioned, Among these, it is especially preferable to use acryloyl morpholine or isobornyl acrylate.

It is preferable that it is 30 degreeC or more, and, as for the glass transition temperature of the Tg-adjusting monomer mentioned above, it is especially preferable that it is 50 degreeC or more, and it is preferable that it is also 90 degreeC or more. Moreover, it is preferable that it is 200 degrees C or less, and, as for the glass transition temperature of a Tg-adjusting monomer, it is especially preferable that it is 180 degrees C or less, and it is preferable that it is 150 degrees C or less. By using the Tg adjustment monomer which has a glass transition temperature of such a range, it becomes easy to adjust the glass transition temperature of an active-energy-ray-curable adhesive to the above-mentioned range. In addition, in this specification, the glass transition temperature with respect to a monomer shall mean the glass transition temperature measured with respect to the homopolymer which consists only of the said monomer.

Moreover, it is preferable that it is 9.8 or more, and, as for the dissolution parameter (SP value) of the above-mentioned Tg-adjusting monomer, it is especially preferable that it is 9.9 or more, and it is more preferable that it is 10.0 or more. When the SP value of the Tg adjustment monomer is 9.8 or more, it becomes easy to adjust the adhesive force of the sheet for work processing to the above-mentioned range, and especially, it becomes easy to adjust the initial adhesive force F0 to the above-mentioned range. For this reason, it becomes easy to hold|maintain a workpiece|work on the sheet|seat for a workpiece|work at the time of a process. Moreover, it does not specifically limit about the upper limit of a dissolution parameter (SP value), For example, 11 or less may be sufficient.

The acrylic copolymer (a1) preferably contains 3.0 mass% or more of the structural unit derived from the Tg-adjusting monomer, particularly preferably 5.0 mass% or more, and further preferably contains 8.0 mass% or more. . Moreover, it is preferable that the acrylic copolymer (a1) contains 12.0 mass % or less of the structural unit derived from the said Tg-adjusting monomer. When an acrylic copolymer (a1) contains a Tg adjustment monomer in the said range, it becomes easy to adjust the glass transition temperature of the active energy ray-curable adhesive obtained to the above-mentioned range.

As for the acrylic copolymer (a1), it is also preferable to use a (meth)acrylic acid alkyl ester monomer having an alkyl group having 1 to 20 carbon atoms as a monomer unit constituting the polymer. As such a (meth)acrylic acid alkyl ester monomer, the (meth)acrylic acid alkyl ester monomer whose C1-C18 alkyl group is especially preferable. Moreover, from a viewpoint of being easy to obtain the adhesive excellent in heat resistance, the C8 or more (meth)acrylic acid alkyl ester monomer of an alkyl group is preferable. Preferred examples of the (meth)acrylic acid alkyl ester monomer having an alkyl group having 1 to 20 carbon atoms include methyl methacrylate, ethyl (meth)acrylate, propyl (meth)acrylic acid, n-butyl (meth)acrylate, and (meth)acrylic acid 2 -Ethylhexyl etc. are mentioned. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The acrylic copolymer (a1) preferably contains 50% by mass or more of a structural unit derived from the above-mentioned (meth)acrylic acid alkyl ester monomer having 1 to 20 carbon atoms in the alkyl group, particularly 60% by mass or more. It is preferable, and it is preferable to contain 70 mass % or more. In addition, it is preferable that the acrylic copolymer (a1) contains 99 mass % or less of a structural unit derived from the above-mentioned alkyl group (meth) acrylic acid alkyl ester monomer having 1 to 20 carbon atoms, particularly 95 mass % It is preferable to contain below 90 mass %, and it is preferable to contain.

The acrylic copolymer (a1) is preferably obtained by copolymerizing the above-described monomers or derivatives thereof by a conventional method. In addition to these monomers, monomers having an alicyclic structure in the molecule (monomers containing an alicyclic structure), dimethyl acrylamide , vinyl formate, styrene, etc. may be copolymerized.

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

An active energy ray-curable polymer (A) is obtained by making the acrylic copolymer (a1) which has the said functional group containing monomer unit react with the unsaturated group containing compound (a2) which has the functional group couple|bonded with the functional group.

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

Further, the unsaturated group-containing compound (a2) contains at least one active energy ray polymerizable carbon-carbon double bond per molecule, preferably 1 to 6, more preferably 1 to 4 carbon-carbon double bonds. Specific examples of the unsaturated group-containing compound (a2) include 2-methacryloyloxyethyl isocyanate, metaisopropenyl α,α-dimethyl benzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1 , 1-(bisacryloyloxy methyl) ethyl isocyanate; an acryloyl monoisocyanate compound obtained by reaction of a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth)acrylate; acryloyl monoisocyanate compound obtained by reaction of a diisocyanate compound or a polyisocyanate compound, a polyol compound, and hydroxyethyl (meth)acrylate; (meth) glycidyl acrylate; (meth)acrylic acid, (meth)acrylic acid 2-(1-aziridinyl)ethyl, 2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline, etc. are mentioned.

The unsaturated group-containing compound (a2) is, with respect to the number of moles of the functional group-containing monomer of the acrylic copolymer (a1), preferably 50 mol% or more, particularly preferably 60 mol% or more, more preferably 70 mol% or more used as a ratio. In addition, the unsaturated group-containing compound (a2) is preferably 95 mol% or less, particularly preferably 93 mol% or less, more preferably 90 mol% or less, based on the number of moles of the functional group-containing monomer of the acrylic copolymer (a1). It is used in a proportion of 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 temperature, pressure, and solvent of the reaction , time, the presence or absence of a catalyst, and the type of catalyst can be appropriately selected. For this reason, the functional group present in the acrylic copolymer (a1) reacts with the functional group in the unsaturated group-containing compound (a2), the unsaturated group is introduced into the side chain in the acrylic copolymer (a1), and an active energy ray-curable polymer (A) is obtained lose

It is preferable that the weight average molecular weight (Mw) of the active energy ray-curable polymer (A) obtained in this way is 10,000 or more, It is especially preferable that it is 150,000 or more, It is also preferable that it is 200,000 or more. Moreover, it is preferable that it is 1.5 million or less, and, as for the said weight average molecular weight (Mw), it is especially preferable that it is 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 an active energy ray-curable adhesive has as a main component the polymer which has active energy ray sclerosis|hardenability like an active energy ray-curable polymer (A), an active energy ray-curable adhesive is an active energy ray-curable monomer and/or oligomer (B) ) may be further contained.

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

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

When blending the active energy ray-curable monomer and/or oligomer (B) with respect to the active energy ray-curable polymer (A), the active energy ray-curable monomer and/or oligomer (B) in the active energy ray-curable adhesive It is preferable that content is more than 0 mass parts with respect to 100 mass parts of active energy ray-curable polymers (A), and it is especially preferable that it is 60 mass parts or more. 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, as for the said content, it is especially preferable that it is 200 mass parts or less.

Here, when using ultraviolet rays 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 use of the photopolymerization initiator (C), polymerization curing time and light irradiation amount can reduce

As for the photoinitiator (C) in this embodiment, it is preferable that the 5% weight loss temperature is 200 degreeC or more, It is especially preferable that it is 210 degreeC or more, It is also preferable that it is 220 degreeC or more. By using the photopolymerization initiator (C) exhibiting a 5% weight loss temperature of 200° C. or higher, it is easy to adjust the adhesive force of the sheet for work processing to the above-mentioned range, and in particular, after heating and active energy irradiation, the adhesive strength F2 is brought into the above-mentioned range. Easier to adjust For this reason, even when heat processing is performed, it becomes easy to isolate|separate the workpiece|work after a process from the sheet|seat for a workpiece|work process easily. Moreover, about the upper limit of 5% weight loss temperature, it does not specifically limit, For example, 300 degrees C or less may be sufficient, especially 280 degrees C or less may be sufficient, and 250 degrees C or less may be sufficient. In addition, the detail of the measuring method of the said 5% weight loss temperature is as described in the Example mentioned 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 methyl benzoate. , benzoin dimethyl ketal, 2,4-diethylthioxanthone, 1-hydroxycyclohexylphenyl ketone, benzyl diphenyl sulfide, tetramethyl thiuram monosulfide, azobis isobutyronitrile, benzyl, dibenzyl, di Acetyl, β-chloroanthraquinone, (2, 4, 6-trimethyl benzyl diphenyl) phosphine oxide, 2-benzothiazole-N,N-diethyldithiocarbamate, oligo(2-hydroxy) -2-methyl-1-[4-(1-propenyl)phenyl]propanone｝, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-hydroxy-1-b4 -[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl--2-methyl-propan-1-one etc. are mentioned. Among these, it is preferable to use 2-hydroxy-1-b4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl--2-methyl-propan-1-one. . These may be used independently and may use 2 or more types together.

A photoinitiator (C), when mix|blending an active energy ray-curable polymer (A) (an active energy ray-curable monomer and/or an 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 the oligomer (B)) It is preferably used in an amount of 0.1 parts by mass or more, particularly 0.5 parts by mass or more with respect to 100 parts by mass. In addition, a photoinitiator (C) is an active energy ray-curable polymer (A) (When mix|blending an active energy ray-curable monomer and/or an oligomer (B), an active energy ray-curable polymer (A) and active energy ray-curable polymer) 100 parts by mass of the total amount of the monomers and/or oligomers (B)) of 10 parts by mass or less, particularly preferably 6 parts by mass or less with respect to 100 parts by mass.

In an active energy ray-curable adhesive, you may mix|blend other components suitably other than the said component. As another component, 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, and polyolefins, and have a weight average molecular weight (Mw) of 3000 to 250 Only polymers or oligomers are preferred. By mix|blending the said component (D) with an active energy ray-curable adhesive, the adhesiveness and peelability before hardening, the intensity|strength after hardening, adhesiveness with another layer, storage stability, etc. can be improved. The compounding quantity of the said component (D) is not specifically limited, It determines suitably in the range of more than 0 mass parts and 50 mass parts or less with respect to 100 mass parts of active energy ray-curable polymers (A).

As a crosslinking agent (E), the polyfunctional compound which has reactivity with the functional group which an active energy ray-curable polymer (A) etc. has 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.

It is preferable that the compounding quantity of a crosslinking agent (E) is 0.01 mass part or more with respect to 100 mass parts of active energy ray-curable polymers (A), and it is especially preferable that it is 1 mass part or more. Moreover, it is preferable that it is 20 mass parts or less with respect to 100 mass parts of active energy ray-curable polymers (A), and, as for the compounding quantity of a crosslinking agent (E), it is especially preferable that it is 17 mass parts or less.

Next, the case where an active energy ray-curable adhesive has as a main component the mixture of an active energy ray non-curable polymer component, and the monomer and/or oligomer which has at least 1 or more active energy ray-curable group is demonstrated below.

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

As a monomer and/or an oligomer which has at least 1 or more active energy ray-curable group, the thing similar to the above-mentioned component (B) 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 or more active energy ray-curable groups with respect to 100 parts by mass of the active energy ray non-curable polymer component. It is preferable that it is 1 mass part or more of a monomer and/or an oligomer, 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 an oligomer having at least one active energy ray-curable group with respect to 100 parts by mass of the active energy ray-curable polymer component, and particularly preferably 160 parts by mass or less. .

Also in this case, similarly to the above, a photoinitiator (C) and a crosslinking agent (E) can be mix|blended suitably.

It is preferable that it is 1 micrometer or more, and, as for adhesive layer thickness, it is preferable that it is 5 micrometers or more. Moreover, it is preferable that it is 50 micrometers or less, and, as for the said thickness, it is preferable that it is 40 micrometers or less. It becomes easy to achieve the adhesive force mentioned above that adhesive layer thickness is the said range.

(3) release sheet

In the sheet for work processing according to the present embodiment, the surface (hereinafter, sometimes referred to as "adhesive surface") on the opposite side to the base material in the pressure-sensitive adhesive layer is adhered to the work for the purpose of protecting the surface, The release sheet may be laminated|stacked on the said surface. The structure of a release sheet is arbitrary, and what carried out the peeling process of the plastic film with a release agent etc. is illustrated. 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 silicones having stable performance at low cost are preferable. Although there is no restriction|limiting in particular about the thickness of a peeling sheet, Usually, they are 20 micrometers or more and 250 micrometers or less.

(4) Other absences

In the sheet for work processing which concerns on this embodiment, the adhesive bond layer may be laminated|stacked on the adhesive surface in an adhesive layer. In this case, the sheet for work processing according to the present embodiment can be used as a dicing die-bonding sheet by providing the adhesive layer as described above. In such a work-processing sheet, a chip|tip in which the adhesive bond layer divided into pieces is laminated|stacked can be obtained by affixing a workpiece|work to the surface opposite to the adhesive layer in an adhesive bond layer, and dicing the adhesive bond layer together with the said workpiece|work. The chip can be easily fixed to a target on which the chip is mounted by the separated adhesive layer. As the material constituting the adhesive layer described above, it is preferable to use a material containing a thermoplastic resin and a low molecular weight thermosetting adhesive component, or a material containing a B-stage (semi-cured image) thermosetting adhesive component.

Moreover, in the sheet|seat for a work process which concerns on this embodiment, the protective film forming layer may be laminated|stacked on the adhesive surface in an adhesive layer. In this case, the sheet for work processing according to the present embodiment can be used as a sheet for forming a protective film and for dicing. In such a sheet for work processing, a chip in which the protective film forming layer is laminated in pieces can be obtained by affixing the work on the surface opposite to the pressure-sensitive adhesive layer in the protective film forming layer and dicing the protective film forming layer together with the work. It is preferable that a circuit formed on one surface is used as the work, and in this case, a protective film forming layer is usually laminated on the surface opposite to the surface on which the circuit is formed. By hardening the separated protective film forming layer at a predetermined timing, a protective film having sufficient durability can be formed on the chip. It is preferable that a protective film forming layer consists of a non-hardened curable adhesive agent.

Moreover, it is preferable that the sheet|seat for work processing which concerns on this embodiment satisfy|fills the above-mentioned conditions with respect to adhesive force, but when the adhesive bond layer or protective film forming layer mentioned above with respect to an adhesive layer is laminated|stacked, the adhesive layer before this layer is laminated|stacked. With respect to it, what is necessary is just to satisfy the adhesive force mentioned above.

3. Manufacturing method of sheet for workpiece processing

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

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 transcribe|transfer the adhesive layer formed on the peeling sheet to the single side|surface side of a base material. In this case, the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer and, if desired, a coating solution further containing a solvent or a dispersion medium are prepared, and on the peeling-treated side of the release sheet (hereinafter referred to as “peelable side”). , a die coater, a curtain coater, a spray coater, a slit coater, a knife coater, or the like to form a coating film by applying the coating solution, and drying the coating film to form an adhesive layer. The coating liquid will not specifically limit the property as long as it can apply|coat, The component for forming an adhesive layer may be contained as a solute, and may contain it as a dispersoid. The release sheet in this laminate may peel as a process material, and you may use it in order to protect the adhesive surface of an adhesive layer until the sheet|seat for a work process is affixed to a work.

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

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

4. How to use the sheet for workpiece processing

The sheet for workpiece processing according to the present embodiment can be used for processing a workpiece. That is, after affixing the adhesive surface of the sheet|seat for a workpiece|work which concerns on this embodiment to a workpiece|work, a workpiece|work can be processed on the sheet|seat for a 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, a dicing sheet, an expansion sheet, a pickup sheet, or the like. Here, as an example of a workpiece|work, glass members, such as semiconductor members, such as a semiconductor wafer and a semiconductor package, and a glass plate, are mentioned.

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

When the processing of the workpiece is completed on the sheet for processing the workpiece according to the present embodiment and the workpiece after processing is separated from the sheet for processing the workpiece, the pressure-sensitive adhesive layer of the sheet for processing the workpiece is preferably irradiated with an active energy ray before the separation. . For this reason, an adhesive layer hardens|cures, the adhesive force of the sheet|seat for work processing with respect to the workpiece|work after a process falls favorably, and isolation|separation of the workpiece|work after a process becomes easy.

As the above-mentioned active energy rays, for example, those having energy protons among electromagnetic waves or charged particle beams can be used, and specifically, ultraviolet rays, electron beams, and the like can be used. In particular, an easy-to-handle ultraviolet ray is preferable. Irradiation of ultraviolet rays can be performed by a high-pressure mercury lamp, a xenon lamp, LED, etc., and it is preferable that the irradiation amount of ultraviolet-ray is 50 mW/cm<2> or more and 1000 mW/cm<2> or less of illumination intensity. The amount of light is preferably 50 mJ/cm 2 or more, particularly preferably 80 mJ/cm 2 or more, and more preferably 200 mJ/cm 2 or more. The amount of light is preferably 10000 mJ/cm 2 or less, particularly preferably 5000 mJ/cm 2 or less, and more preferably 2000 mJ/cm 2 or less. On the other hand, irradiation of an electron beam can be performed by an electron beam accelerator etc., and, as for the irradiation amount of an electron beam, 10 krad or more and 1000 krad or less are preferable.

In the sheet for work processing according to the present embodiment, when the adhesive force F0 falls within the above-described range, sufficient adhesive force is exhibited with respect to the work during processing of the work, and defects such as movement or dropout of the work or the work after machining are satisfactory. can be suppressed. In addition, when the adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive and the adhesive force ratio F2/F0 falls within the above-mentioned range, even when the sheet for processing a workpiece is heated in a state in which the workpiece after processing is affixed, thereafter, active energy ray By irradiating , the adhesive force to the workpiece after processing can be sufficiently reduced, whereby the workpiece after processing can be picked up favorably. For this reason, the sheet|seat for work processing which concerns on this embodiment can be used suitably with respect to the use in which the sheet|seat for work processing is exposed to a high-temperature environment in the state in which the workpiece|work or the workpiece|work after processing was stuck on the sheet|seat for work processing. In particular, the sheet for work processing according to the present embodiment is suitable for use in applications in which dicing of a silicon wafer or the like is performed on the sheet for work processing, and heat treatment is performed on the obtained chip on the sheet for work processing.

When the sheet for work processing according to the present embodiment is used as a dicing sheet and used for a heat treatment in which a chip is affixed on a sheet for work processing after dicing, the heating conditions are, for example, , the heating temperature is preferably 40°C or higher, particularly preferably 80°C or higher, and more preferably 100°C or higher. Moreover, it is preferable that the said heating temperature shall be 150 degrees C or less, It is especially preferable to set it as 130 degrees C or less, Furthermore, it is preferable to set it as 120 degrees C or less. Further, the heating time is preferably set to, for example, 3 minutes or longer, particularly preferably 10 minutes or longer, and more preferably 30 minutes or longer. Moreover, it is preferable to make the said heating time into 60 minutes or less, It is especially preferable to set it as 50 minutes or less, Furthermore, it is preferable to set it as 40 minutes or less. Even when the sheet for work processing which concerns on this embodiment is heated under the conditions as mentioned above, a chip|tip can be isolate|separated favorably.

The embodiment described above is described in order to facilitate the understanding of the present invention, and is not described in order to limit the present invention. Accordingly, 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 a base material and an adhesive layer, or in the surface on the opposite side to the adhesive layer in a base material.

Example

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

[Example 1]

(1) Preparation of pressure-sensitive adhesive composition

90 parts by mole of the acrylic copolymer obtained by copolymerizing 70 parts by mass of 2-ethylhexyl acrylate, 10 parts by mass of acryloyl morpholine, and 20 parts by mass of 2-hydroxyethyl acrylate, and 2-hydroxyethyl acrylate in the acrylic copolymer Molar% of methacryloyloxyethyl isocyanate (MOI) was made to react, and the active energy ray-curable polymer was obtained. Although the weight average molecular weight (Mw) of this active energy ray-curable polymer was measured by the method mentioned later, it was 830,000.

Photopolymerization with 100 parts by mass of the obtained active energy ray-curable polymer (in terms of solid content, hereinafter the same) and 1.2 parts by mass of an aliphatic isocyanate (Nippon Polyurethane Industry Co., Ltd., product name "Coronate HX") having hexamethylene diisocyanate as a crosslinking agent As an initiator 2-hydroxy-1-b4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl--2-methyl-propan-1-one (manufactured by BASF, product name " Omnirad 127", 5% weight loss temperature: 220 degreeC) 1.2 mass parts were mixed in a solvent, and the adhesive composition was obtained. In addition, the 5% weight loss temperature of the photoinitiator is measured by heating at a temperature increase rate of 5 °C/min from room temperature to 300 °C using a differential thermal and thermogravimetric simultaneous measurement apparatus (manufactured by SHIMADZU, product name "DTG-60"). did it

(2) Formation of the pressure-sensitive adhesive layer

To the release surface of a release sheet (manufactured by LINTEC Corporation, product name "SP-PET381031") in which a silicone-based release agent layer is formed on one surface of a 38 µm-thick polyethylene terephthalate film, the pressure-sensitive adhesive composition is applied and heated After drying, the adhesive layer with a thickness of 5 micrometers was formed on the release sheet by curing for 7 days under 23 degreeC and 50 %RH conditions.

(3) Fabrication of sheet for workpiece processing

By bonding the side opposite to the release sheet of the pressure-sensitive adhesive layer formed in the step (2) and one side of a polyester film having a heat resistance of 75 μm in thickness as a substrate (manufactured by KURABO, product name “Torcena”), A sheet for work processing was obtained.

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

[Examples 2 to 8 and Comparative Examples 1 to 4]

A sheet for work processing was prepared in the same manner as in Example 1 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 pressure-sensitive adhesive composition was changed as shown in Table 2.

[Test Example 1] (Measurement of the glass transition temperature of the adhesive)

By laminating a plurality of pressure-sensitive adhesive layers of the sheet for work processing produced in Examples and Comparative Examples, a laminate of 800 µm-thick pressure-sensitive adhesive layers was produced. Then, the sample for a measurement was obtained by piercing|piercing the laminated body of this adhesive layer circularly with a diameter of 10 mm. For the sample for measurement, using a dynamic viscoelasticity measuring device (manufactured by TA Instruments, product name “ARES”), tan δ was measured under the conditions of a frequency of 1 Hz, a measurement temperature range of -50 to 150° C., and a temperature increase rate of 3° C./min. and the temperature of the peak top was set to Tg. A result is shown in Table 3.

[Test Example 2] (Measurement of adhesive force)

The sheet for work processing manufactured in the Example and the comparative example was cut into the strip shape of 25 mm width. With respect to the above-mentioned mirror surface of a silicon wafer obtained by peeling the release sheet from the obtained strip-shaped work-processing sheet and mirror-finishing the exposed adhesive surface of the pressure-sensitive adhesive layer, under an environment of a temperature of 23°C and a relative humidity of 50%, 2 kg rubber It was bonded together using a roller, and it left still for 20 minutes, and it was set as the sample for a measurement.

For the obtained measurement sample, the workpiece was removed from the silicon wafer using a universal tensile tester (manufactured by ORIENTEC Co., Ltd., product name "Tensiron UTM-4-100") at a peeling rate of 300 mm/min and a peeling angle of 180°. The sheet for processing was peeled, and the adhesive force (mN/25 mm) with respect to a silicon wafer was measured according to the 180 degree peeling method according to JIS Z0237:2009. The adhesive force obtained by this is shown in Table 3 as adhesive force F0.

Moreover, the sample for a measurement obtained similarly to the above was heated at 150 degreeC for 1 hour using oven. About the sample for measurement after the said heating, the adhesive force (mN/25 mm) with respect to a silicon wafer was measured similarly to the above. The adhesive force obtained by this is shown in Table 3 as adhesive force F1.

Moreover, the sample for a measurement obtained similarly to the above was heated at 150 degreeC for 1 hour using oven. Moreover, with respect to the adhesive layer, ultraviolet irradiation was performed through the base material on condition of the following. About this measurement sample, the adhesive force (mN/25 mm) with respect to a silicon wafer was measured similarly to the above. The adhesive force obtained by this is shown in Table 3 as adhesive force F2.

<Ultraviolet irradiation conditions>

・Use of high pressure mercury lamp

Illuminance 230 mW/cm2, light intensity 190 mJ/cm2

・UV illuminance and light meter use "UVPF-A1" manufactured by iGrafx

In addition, the ratio of the adhesive force F2 to the adhesive force F0 (F2/F0) and the ratio of the adhesive force F0 to the adhesive force F1 (F0/F1) were calculated from the three kinds of adhesive forces obtained as described above, respectively. These results are shown in Table 3.

[Test Example 3] (Measurement of Young's Modulus of Adhesive)

A plurality of laminates of the pressure-sensitive adhesive layer and release sheet produced in the same manner as in the step (2) of Example 1 were prepared for each of Examples and Comparative Examples. And the adhesive layer sample for a measurement which consists of a 200-micrometer-thick adhesive layer by laminating|stacking a predetermined number of the adhesive layers in the said laminated body was produced.

The obtained pressure-sensitive adhesive layer sample for measurement was pulled using a universal tensile tester (manufactured by Shimadzu Corporation, product name “Autograph AG-IS”) at 23° C., a distance between chucks of 30 mm, and a speed of 200 mm/min, and the resulting stress- The Young's modulus (MPa) was determined by the strain curve. The result obtained by this is shown in Table 3 as Young's modulus E0.

Moreover, the adhesive layer sample for a measurement obtained similarly to the above was heated at 150 degreeC for 1 hour using oven. About the adhesive layer sample for a measurement after the said heating, the Young's modulus (MPa) was calculated|required similarly to the above. The result obtained by this is shown in Table 3 as Young's modulus E1.

Moreover, the adhesive layer sample for a measurement obtained similarly to the above was heated at 150 degreeC for 1 hour using oven. Moreover, ultraviolet irradiation was performed on the following conditions about the adhesive layer sample for a measurement after the said heating. About this adhesive layer sample for a measurement, the Young's modulus (MPa) was calculated|required similarly to the above. The result obtained by this is shown in Table 3 as Young's modulus E2.

<Ultraviolet irradiation conditions>

・Use of high pressure mercury lamp

Illuminance 230 mW/cm2, light intensity 580 mJ/cm2

・UV illuminance and light meter use "UVPF-A1" manufactured by iGrafx

Further, the ratio of the Young's modulus E1 to the Young's modulus E0 (E1/E0) and the ratio of the Young's modulus E2 to the Young's modulus E1 (E2/E1) were calculated from the three types of Young's modulus obtained as described above, respectively. These results are shown in Table 3.

[Test Example 4] (Evaluation of initial adhesiveness)

The release sheet was peeled from the sheet for work processing produced in Examples and Comparative Examples, and a tape mounter (manufactured by LINTEC Corporation, product name "Adwill RAD2500m/12") was used on the exposed surface of the exposed pressure-sensitive adhesive layer, and #2000 was polished. A polished surface of a 6-inch silicon wafer (thickness: 350 µm) was affixed. Then, using a dicing apparatus (manufactured by DISCO Corporation, product name "DFD-6362"), dicing was performed to cut from the 6-inch silicon wafer side while supplying water flowing to the cut portion under the following dicing conditions.

<Dicing conditions>

・Dicing device: DFD-6362 manufactured by DISCO Corporation

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

・Blade width　　：0.025 ~ 0.030mm

・Knife tip protrusion 　　：0.640 ~ 0.760mm

・Blade rotation speed: 50000rpm

・Cutting speed　　　: 20mm/sec

・Notch depth 　: 20 μm with respect to the substrate from the surface on the adhesive layer side of the sheet for work processing

・Flowing water supply 　　: 1.0L/min

・Flowing water temperature　　　: Room temperature

・Cut size　：2mm×2mm

Thereafter, the sheet for work processing to which the chips obtained by the dicing process are adhered is visually observed, and the number of chips dropped from the sheet for work processing during the dicing process is counted, and the number is divided by the number of divisions in the dicing process By dividing, the chip scattering rate (unit: %) was calculated|required. Based on this calculation result, initial stage adhesiveness was evaluated on the basis of the following. Table 3 shows the evaluation results.

(circle): The chip|tip scattering rate is less than 10 %.

x: The chip scattering rate is 10 % or more.

[Test Example 5] (Evaluation of pickup aptitude)

Dicing was performed in the same manner as in Test Example 4 using the sheet for work processing produced in Examples and Comparative Examples, except that the cut size was changed to 10 mm x 10 mm.

After completion of dicing, the sheet|seat for work processing in the state in which the chip|tip was mounted was put into oven, and it heated at 150 degreeC for 1 hour. Then, with respect to the adhesive layer in the sheet|seat for a work process, ultraviolet irradiation was performed through the base material on the following conditions.

<Ultraviolet irradiation conditions>

・Use of high pressure mercury lamp

Illuminance 230 mW/cm2, light intensity 190 mJ/cm2

・UV illuminance and light meter use "UVPF-A1" manufactured by iGrafx

100 chips were picked up from the sheet|seat for work processing after ultraviolet irradiation, and pick-up aptitude was evaluated based on the following criteria. A result is shown in Table 3.

(double-circle): The number of chips which could be picked up favorably among 100 pieces was 95 or more.

(circle): The number of chips which could be picked up favorably among 100 pieces was 80 or more less than 95 pieces.

x: The number of chips which could be picked up favorably among 100 pieces was less than 80 pieces.

In addition, details, such as the abbreviation of Table 1 and Table 2, are as follows.

[Composition of active energy ray-curable polymer]

2EHA: Acrylic acid 2-ethylhexyl

BA: butyl acrylate

ACMO: acryloyl morpholine (SP value: 10.1, glass transition temperature: 145°C)

MMA: methyl methacrylate (SP value: 9.5, glass transition temperature: 105°C)

IBXA: isobornyl acrylate (SP value: 10.2, glass transition temperature: 94°C)

HEA: Acrylic acid 2-hydroxyethyl

MOI: methacryloyloxyethyl isocyanate

[Photoinitiator]

Omnirad 127: 2-hydroxy-1-b4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenylb-2-methyl-propan-1-one (manufactured by BASF, product name) 「Omnirad 127」, 5% weight reduction temperature：220℃)

Omnirad TPO: 2, 4, 6-trimethylbenzoyl diphenyl phosphine oxide (manufactured by BASF, product name "Omnirad TPO", 5% weight loss temperature: 225°C)

As can be seen from Table 3, the sheet for work processing obtained in Examples was excellent in initial adhesiveness and was able to hold the work satisfactorily on the sheet during processing of the work. Moreover, it was suggested that the sheet|seat for work processing obtained in the Example was excellent in pick-up aptitude, ie, at the time of pick-up, that the adhesive force with respect to the workpiece|work after a process is falling favorably.

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

Claims (6)

A sheet for work processing comprising a substrate and an adhesive layer laminated on one side of the substrate,
The pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive,
Let the adhesive force of the sheet for work processing to a silicon wafer be F0,
After the laminate formed by bonding the sheet for work processing to a silicon wafer is heated at 150° C. for 1 hour, the pressure-sensitive adhesive layer constituting the laminate is further irradiated with active energy rays, and then the sheet for work processing on the silicon wafer. When the adhesive force is set to F2,
The adhesive force F0 is 600 mN/25 mm or more and 20000 mN/25 mm or less,
The ratio of the adhesive force F2 to the adhesive force F0 (F2/F0) is 0.66 or less, the sheet for work processing. According to claim 1,
After heating the sheet for work processing at 150°C for 1 hour, the Young's modulus at 23°C of the pressure-sensitive adhesive layer is E1,
After heating the sheet for work processing at 150° C. for 1 hour, after further irradiating an active energy ray with respect to the pressure-sensitive adhesive layer constituting the sheet for work processing, the Young's modulus at 23° C. of the pressure-sensitive adhesive layer is E2,
The ratio (E2/E1) of the Young's modulus E2 to the Young's modulus E1 is 13 or more. 3. The method of claim 1 or 2,
In the sheet for work processing, the Young's modulus at 23° C. of the pressure-sensitive adhesive layer is E0,
After heating the sheet for work processing at 150° C. for 1 hour, when the Young’s modulus at 23° C. of the pressure-sensitive adhesive layer is E1,
The ratio (E1/E0) of the Young's modulus E1 to the Young's modulus E0 is 2.0 or more. 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 glass transition temperature of the active energy ray-curable pressure-sensitive adhesive is -50°C or more and 10°C or less,
The active energy ray-curable pressure-sensitive adhesive comprises an acrylic copolymer comprising a monomer having a polar group as a constituent monomer, the sheet for work processing. 5. The method of claim 4,
The acrylic copolymer is a sheet for work processing, characterized in that a functional group having active energy ray curability is introduced into the side chain. 6. The method according to any one of claims 1 to 5,
A sheet for work processing, characterized in that it is a dicing sheet.