TWI809030B - Sheet material for workpiece processing and method of manufacturing the processed workpiece - Google Patents

Abstract

A sheet for workpiece processing, which is a sheet for workpiece processing comprising a base material and an adhesive layer laminated on one side of the base material, wherein the adhesive layer is composed of an active energy ray-curable adhesive, and the above-mentioned The surface of the adhesive layer on the opposite side to the base material has an oxygen atomic ratio _R0 measured by X-ray photoelectron spectroscopy analysis of 28 atomic % or less, and is located within the adhesive layer at a distance from the adhesive layer. In the position where the depth of the surface of the agent layer opposite to the substrate is 100 nm, the oxygen atomic ratio R ₁₀₀ measured by X-ray photoelectron spectroscopy is 20 atomic % or more and 29 atomic % or less. Such a workpiece processing sheet can well remove the adhesive originating from the adhesive layer attached to the processed workpiece by flowing water, and can also separate the processed workpiece favorably.

Description

Sheet for workpiece processing and method for manufacturing finished workpiece

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

Semiconductor wafers such as silicon and gallium arsenide, and various package types (hereinafter sometimes collectively referred to as "cut objects") are manufactured in a large-diameter state, and these are cut (diced) into components Chips (hereinafter sometimes referred to as "wafers") are individually separated (pickup) at the same time, and then transferred to the next step of the mounting (mount) process. At this time, the workpiece to be cut such as a semiconductor wafer is cut, cleaned, dried, expanded, picked up, and mounted in a state where a workpiece processing sheet having a base material and an adhesive layer is attached ( mounting) steps.

In the above cutting step, the cutting blade, the object to be cut, and the sheet for workpiece processing are heated due to frictional heat generated between the rotating cutting blade and the object to be cut or the sheet for processing the workpiece. Furthermore, in the dicing process, dicing debris may be generated from the object to be cut or the sheet for workpiece processing, and may adhere to the wafer.

Therefore, when the dicing process is performed, running water is usually supplied to the dicing portion to cool the dicing blade and the like, and at the same time remove the generated dicing debris from the wafer.

For the purpose of promoting the removal of cutting chips by running water, Patent Document 1 discloses a sheet for workpiece processing, in which the surface of the adhesive layer before ultraviolet irradiation is on the opposite side from the substrate, which is in contact with pure water. The angle is 82° to 114°, the contact angle to diiodomethane is 44° to 64°, and the peak of the probe tack test in the adhesive layer before ultraviolet irradiation is 294 to 578kPa. [Prior art literature] [Patent Document]

[Patent Document 1] Japanese Patent No. 5019657

[Problems to be Solved by the Invention]

However, when the cutting process is performed using the conventional workpiece processing sheet disclosed in Patent Document 1, the adhesive originating from the adhesive layer of the workpiece processing sheet cannot be sufficiently removed from the processed workpiece.

Furthermore, in general, when the wafer is separated from the workpiece processing sheet in the pick-up step, it is required to be able to separate without applying excessive force so that defects such as damage to the wafer do not occur.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method capable of removing the adhesive originating from the adhesive layer adhering to the processed workpiece well by flowing water, and at the same time, capable of separating the processed workpiece well. A sheet for processing a workpiece, and a method for manufacturing a processed workpiece using the sheet for processing a workpiece. [Means used to solve the problem]

In order to achieve the above object, first, the present invention provides a sheet for workpiece processing, which is a sheet for workpiece processing comprising a base material and an adhesive layer laminated on one side of the base material, wherein the adhesive layer is composed of an active Consisting of an energy ray curable adhesive, the oxygen atomic ratio _R0 measured by X-ray photoelectron spectroscopy on the surface of the adhesive layer opposite to the base material is 28 atomic % or less, and in the aforementioned At a position within the adhesive layer at a depth of 100 nm from the surface of the adhesive layer opposite to the base material, the oxygen atomic ratio R ₁₀₀ measured by X-ray photoelectron spectroscopy is 20 atoms % or more and 29 atomic % or less (Invention 1).

In the sheet for workpiece processing according to the above invention (Invention 1), the surface of the adhesive layer on the opposite side to the base material (hereinafter sometimes referred to as "adhesive surface"), utilizes X-ray photoelectron spectroscopy The oxygen atomic ratio _R0 measured by analysis is 28 atomic % or less, so that the adhesive surface has moderate hydrophobicity, and the workpiece after processing becomes easy to separate well. In addition, the oxygen atomic ratio R ₁₀₀ measured by X-ray photoelectron spectroscopy at a position within the adhesive layer at a depth of 100 nm from the adhesive surface is 20 atomic % or more and 29 atomic % or less , so that the surface of the adhesive attached to the processed workpiece becomes moderately hydrophilic, and the adhesive attached to the processed workpiece can be removed well by running water.

In the above invention (invention 1), the value of the aforementioned oxygen atomic ratio R ₀ is greater than the value of the aforementioned oxygen atomic ratio R ₁₀₀ , and the reduction rate (%) of the oxygen atomic ratio according to the following formula (1) = {(oxygen atomic ratio R ₀ −oxygen atomic ratio R ₁₀₀ )/oxygen atomic ratio R ₀ }×100 (1) The calculated decrease rate of the oxygen atomic ratio is preferably 0% or more and 15% or less (Invention 2).

In the above inventions (Inventions 1 and 2), it is preferable that the active energy ray-curable adhesive is formed of an adhesive composition containing an active energy ray-polymerizable branched polymer (Invention 3).

In the above inventions (Inventions 1 to 3), the adhesive composition contains an acrylic copolymer having a monomer unit containing a functional group, and an unsaturated group-containing copolymer having a functional group bonded to the functional group. The active energy ray-curable polymer obtained by the reaction of the compound, and the aforementioned acrylic copolymer contains methyl acrylate, 2-methoxyethyl (meth)acrylate, ethyl carbitol (methyl) At least one kind of acrylate and methoxyethylene glycol (meth)acrylate is preferable as the monomer unit constituting the polymer (Invention 4).

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

Second, the present invention provides a method for manufacturing a finished workpiece, which includes: bonding the surface of the adhesive layer of the sheet for workpiece processing (Inventions 1 to 5) on the opposite side to the base material to the workpiece. The bonding step; the processing step of obtaining the processed workpiece laminated on the aforementioned workpiece processing sheet by processing the aforementioned workpiece on the aforementioned workpiece processing sheet; irradiating the aforementioned adhesive agent layer with active energy rays, an irradiation step of curing the adhesive layer so that the adhesive force of the aforementioned workpiece processing sheet to the aforementioned processed workpiece is reduced; and a step of separating the aforementioned processed workpiece from the aforementioned workpiece processing sheet after irradiation with active energy rays Separation step (invention 6). [Effect of the present invention]

According to the workpiece processing sheet of the present invention, the adhesive derived from the adhesive layer adhering to the processed workpiece can be well removed by running water, and the processed workpiece can be separated well. Furthermore, with the manufacturing method of the finished workpiece according to the present invention, it becomes possible to efficiently manufacture the finished workpiece.

Embodiments of the present invention will be described below. [Sheet for workpiece processing] The workpiece processing sheet according to this embodiment includes a base material and an adhesive layer laminated on one side of the base material.

1. Physical properties of workpiece processing sheet According to the workpiece processing sheet according to this embodiment, the oxygen concentration measured by X-ray photoelectron spectroscopy is measured on the surface (adhesive surface) of the adhesive layer opposite to the base material. The atomic ratio R ₀ is 28 atomic % or less. When the oxygen atomic ratio R ₀ is 28 atomic % or less, the adhesive surface becomes moderately hydrophobic, and it is possible to suppress the adhesive force of the workpiece processing sheet from becoming too high to the processed workpiece. Thereby, it becomes possible to satisfactorily separate the processed workpiece from the workpiece processing sheet. In particular, in the case of using a silicon wafer as a workpiece, there are many relatively hydrophilic groups on the surface of the silicon wafer, and the surface can be processed by contacting it with an adhesive surface having moderate hydrophobicity. After the workpiece becomes easy to separate. In addition, the details of the measurement method of the above-mentioned oxygen atomic ratio R ₀ are as described in the test example described later.

When the above-mentioned oxygen atomic ratio R ₀ exceeds 28 atomic %, the adhesive surface becomes relatively highly hydrophilic, and the adhesive force of the workpiece processing sheet to the processed workpiece becomes too high. In this case, excessive force is required to separate the processed workpiece from the workpiece processing sheet, and there is a possibility that the processed workpiece may be damaged. From the viewpoint of avoiding these problems, the above-mentioned oxygen atomic ratio R ₀ is preferably 27 atomic % or less.

Furthermore, the above-mentioned oxygen atomic ratio R ₀ is preferably at least 20 atomic %, particularly preferably at least 22 atomic %. When the above-mentioned oxygen atomic ratio R ₀ is 20 atomic % or more, the adhesive surface becomes moderately hydrophilic, and the sheet for workpiece processing tends to exhibit good adhesion to the workpiece. Thereby, when the workpiece is processed or transported in a state where the workpiece or the processed workpiece is stacked on the workpiece processing sheet, it becomes possible to effectively suppress undesired occurrence of workpieces before and after processing. peel off.

According to the workpiece processing sheet of the present embodiment, at a position within the adhesive layer at a depth of 100 nm from the adhesive surface, the oxygen atomic ratio R ₁₀₀ measured by X-ray photoelectron spectroscopy is 20 atoms. % or more and 29 atomic % or less. Thereby, the adhesive in the adhesive layer becomes moderately hydrophilic.

Generally, when cutting with a cutting blade, a rotating cutting blade contacts an object to be cut while flowing water is supplied to the cutting portion, and cuts the object to be cut. At this time, the rotating cutting blade may contact not only the object to be cut but also the adhesive layer. In such a contact portion, cutting of the adhesive layer occurs, the adhesive constituting the adhesive layer is rolled up by the cutting blade, and as a result, small pieces of adhesive are formed. Such small pieces adhere to the object to be cut, the formed wafer, etc., adversely affect the subsequent processing of the wafer, and become a cause of poor quality of the wafer or a product on which the wafer is mounted. Here, since the adhesive of the small pieces is formed as described above, most of these small pieces exist inside the adhesive layer when the adhesive layer is formed.

According to the workpiece processing sheet of this embodiment, the adhesive inside the adhesive layer is moderately hydrophilic as described above, so even if it is an adhesive that produces small pieces as described above during processing, this When a small piece is attached to a processed workpiece (wafer, etc.), the surface of the small piece also becomes moderately hydrophilic. Therefore, with the sheet for workpiece processing according to the present embodiment, the adhesive adhering thereto can be favorably removed from the processed workpiece by supplying flowing water during processing.

On the other hand, when the oxygen atomic ratio R ₁₀₀ is less than 20 atomic %, the adhesive inside the adhesive layer does not have sufficient affinity for water, and it becomes impossible to remove small pieces of the adhesive from the processed workpiece. fully removed. From the viewpoint of avoiding these problems, the above-mentioned oxygen atomic ratio R ₁₀₀ is preferably 21 atomic % or more.

Furthermore, when the above-mentioned oxygen atomic ratio R ₁₀₀ exceeds 29 atomic %, the adhesive inside the adhesive layer becomes to exhibit excessive affinity for water, and as a result, the surface of the adhesive layer also becomes Has a high affinity for water. Therefore, infiltration of water cannot be suppressed, and problems such as wafer scattering and wafer chipping occur during dicing. From the viewpoint of avoiding these problems, the above-mentioned oxygen atomic ratio R ₁₀₀ is preferably 27 atomic % or less. In addition, the detail of the measuring method of the said oxygen atomic ratio _R100 is as described in the test example mentioned later.

According to the workpiece processing sheet of this embodiment, as long as the oxygen atomic ratio R ₀ and the oxygen atomic ratio R ₁₀₀ are each within the aforementioned range, the value of the oxygen atomic ratio R ₁₀₀ may be greater than the value of the oxygen atomic ratio R ₀ , Alternatively, the value of the oxygen atomic ratio R ₀ may be greater than the value of the oxygen atomic ratio R ₁₀₀ . Alternatively, the oxygen atomic ratio R ₀ and the oxygen atomic ratio R ₁₀₀ may be the same value. In the case where the value of the oxygen atomic ratio R ₀ is larger than the value of the oxygen atomic ratio R ₁₀₀ , according to the following formula (1) the reduction rate of the oxygen atomic ratio (%) = {(oxygen atomic ratio R ₀ - oxygen atomic ratio R ₁₀₀ )/Oxygen atomic ratio R ₀ }×100 (1) The calculated reduction rate of the oxygen atomic ratio is preferably 0% or more, particularly preferably 1% or more, and more preferably 2% or more. In addition, the said reduction rate is preferably 15% or less, especially preferably 12% or less, and further more preferably 10% or less. When the reduction rate of the oxygen atomic ratio is within the above range, it becomes easy to simultaneously satisfy the objectives of good removal of the adhesive by running water and good separation of the processed workpiece from the workpiece processing sheet.

According to the workpiece processing sheet of this embodiment, the adhesion of the workpiece processing sheet to the silicon wafer is preferably 1000mN/25mm or more, particularly preferably 1200mN/25mm or more, and more preferably 1500mN/25mm or more. . The adhesive force here refers to the adhesive force in a state in which the sheet for workpiece processing is not irradiated with active energy rays and the adhesive layer is not yet cured. In addition, throughout this specification, the "adhesive force" described herein means that the sheet for workpiece processing has not been irradiated with active energy rays and the adhesive layer has not yet been cured, even if it does not mention whether or not active energy rays have been irradiated. state of adhesion. When the above-mentioned adhesive force is 1000mN/25mm or more, it becomes easy to hold the workpiece to be processed on the workpiece processing sheet well, and during processing, the workpiece or the processed workpiece is laminated on the workpiece processing sheet In the case of conveying in the upper state, etc., peeling of the workpiece before or after processing can be suppressed favorably. In particular, when the processed workpiece is a wafer, scattering of the wafer from the workpiece processing sheet can be favorably suppressed.

Furthermore, the adhesion force of the workpiece processing sheet to the silicon wafer is preferably below 5000mN/25mm, particularly preferably below 4500mN/25mm, and even more preferably below 3000mN/25mm. When the above-mentioned adhesive force is 5000 mN/25 mm or less, it becomes easy to adjust the adhesive force after irradiation with active energy rays to fall within the range described later. In addition, the details of the method of measuring the adhesion of the workpiece processing sheet to the silicon wafer are described in the test examples described later.

In addition, according to the workpiece processing sheet of this embodiment, after the workpiece processing sheet is irradiated with active energy rays, the adhesive force of the workpiece processing sheet to the silicon wafer is preferably 65 mN/25 mm or less. Since the adhesive force is 65 mN/25 mm or less, it becomes easier to separate the processed workpiece from the workpiece processing sheet by irradiating the workpiece processing sheet with active energy rays after the processing of the workpiece is completed.

2. Components of sheets for workpiece processing (1) Substrate According to the base material of the workpiece processing sheet according to this embodiment, as long as it can exhibit the desired function during the use of the workpiece processing sheet, as long as it exhibits good performance against the active energy rays irradiated for curing the adhesive, Transmittance is sufficient, and it is not specifically limited.

For example, the base material is preferably a resin film whose main component is a resin material. As its specific example, an ethylene-vinyl acetate copolymer film; an ethylene-(meth)acrylic acid copolymer film, ethylene-( Ethylene-based copolymer films such as meth)methyl acrylate copolymer films and other ethylene-(meth)acrylate copolymer films; polyethylene films, polypropylene films, polybutene films, polybutadiene films, Polyolefin-based films such as polymethylpentene films, ethylene-norcamhene copolymer films, and norbornene resin films; polyvinyl chloride-based films such as polyvinyl chloride films and vinyl chloride copolymer films; polyparaphenylene Polyester-based films such as ethylene diformate film, polybutylene terephthalate film, and polyethylene naphthalate film; (meth)acrylate copolymer film; polyurethane film; polyamide film Amine film; polystyrene film; polycarbonate film; fluororesin film, etc. Examples of polyethylene films include low-density polyethylene (LDPE) films, linear low-density polyethylene (LLDPE) films, high-density polyethylene (HDPE) films, and the like. Furthermore, a modified film such as a cross-linked film of the above-mentioned materials or an ionomer film (Ionomer film) can also be used. In addition, the base material may be a laminated film obtained by laminating a plurality of the above-mentioned films. In such a laminated film, the materials constituting each layer may be of the same type or different types. Among the above-mentioned films, it is preferable to use an ethylene-methyl methacrylate copolymer film as a base material from the viewpoint of excellent flexibility. In addition, in this specification, "(meth)acrylic acid" means both acrylic acid and methacrylic acid. The same applies to other similar terms as well.

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

Surface treatments such as primer treatment, corona treatment, and plasma treatment may be applied to the surface of the laminated adhesive layer of the base material in order to improve the adhesiveness with the adhesive layer.

The thickness of the base material can be appropriately set according to the method of using the workpiece processing sheet, but it is usually preferably 20 μm or more, and particularly preferably 25 μm or more. Furthermore, the thickness is generally preferably not more than 450 μm, and is particularly preferably not more than 300 μm.

(2) Adhesive layer The adhesive layer of the workpiece processing sheet according to the present embodiment can exhibit a required adhesive force as long as it is composed of an active energy ray-curable adhesive, and at the same time, the aforementioned oxygen atomic ratio R ₀ and the oxygen atomic ratio R ₁₀₀ are only required to be within the aforementioned ranges, and are not particularly limited.

According to the workpiece processing sheet of this embodiment, since the adhesive layer is composed of an active energy ray-curable adhesive, the processed workpiece attached to the adhesive surface of the adhesive layer is separated from the adhesive surface. In this case, the adhesive layer can be cured by irradiating active energy rays, so that the adhesive force of the workpiece processing sheet to the processed workpiece can be reduced. Thereby, it becomes easy to separate the adhesive surface of the adhesive layer from the workpiece after processing.

The adhesive layer in this embodiment may be formed of an adhesive composition containing an active energy ray curable polymer, or may be formed of an active energy ray non-curable polymer (not curable by active energy ray). polymer) and an adhesive composition of a monomer and/or oligomer having at least one active energy ray curable group.

First, the case where the adhesive layer in this embodiment is formed of an adhesive composition containing an active energy ray-curable polymer will be described below.

Active energy ray curable polymer (meth)acrylate (co)polymer (A) (hereinafter referred to as It is preferably called "active energy ray-curable polymer (A)"). The active energy ray-curable polymer (A) is an acrylic copolymer (a1) having a functional group-containing monomer unit and an unsaturated group-containing compound having a functional group capable of bonding to the above-mentioned functional group. (a2) The polymer obtained by carrying out the reaction is preferable.

In the acrylic copolymer (a1), a monomer for adjusting the hydrophilicity of the acrylic copolymer (a1) (hereinafter sometimes referred to as "hydrophilicity adjusting monomer") is contained as a monomer unit constituting the polymer. ) is preferred, especially, as its specific example, to contain methyl acrylate, 2-methoxyethyl (meth)acrylate, ethyl carbitol (meth)acrylate (ethoxy At least one of ethoxyethyl (meth)acrylate) and methoxyethylene glycol (meth)acrylate is preferable.

Since the acrylic copolymer (a1) in the adhesive sheet according to this embodiment uses the above-mentioned hydrophilicity adjusting monomer, it becomes easy to adjust the oxygen atomic ratio R ₁₀₀ to fall within the aforementioned range. It can be considered that the reason is that most of the above-mentioned hydrophilicity adjusting monomers have relatively many oxygen atoms, and by using the acrylic copolymer (a1) composed of these monomers, the absolute amount of oxygen atoms in the adhesive layer also increases, so it becomes easy to adjust the oxygen atomic ratio R ₁₀₀ to fall within the aforementioned range. However, it is not limited to the above reasons.

In addition, from the viewpoint that the aforementioned oxygen atomic ratio R ₁₀₀ can be easily adjusted to fall within the aforementioned range, in the acrylic copolymer (a1), as a monomer unit constituting the polymer, among the aforementioned monomers , preferably containing at least one of methyl acrylate, 2-methoxyethyl acrylate and methoxyethylene glycol acrylate.

When the acrylic copolymer (a1) contains methyl acrylate as a monomer unit constituting the polymer, the content of methyl acrylate is preferably at least 10% by mass, particularly preferably at least 20% by mass, and preferably at least 30% by mass. The above is better. Furthermore, the content of methyl acrylate is preferably 85% by mass or less. When the content is as described above, it becomes easy to adjust the aforementioned oxygen atomic ratio R ₁₀₀ to the aforementioned range in the formed adhesive layer. In addition, in this specification, content (mass %) of the said methyl acrylate means content with respect to all the monomers which comprise an acrylic-type copolymer (a1). In addition, the content (mass %) of other monomers described later also means the content with respect to all the monomers which comprise acrylic copolymer (a1).

Furthermore, when the acrylic copolymer (a1) contains 2-methoxyethyl acrylate as a monomer unit constituting the polymer, the content of 2-methoxyethyl acrylate is preferably 10% by mass or more, It is particularly preferably at least 20% by mass, and more preferably at least 30% by mass. Furthermore, the content of 2-methoxyethyl acrylate is preferably not more than 85% by mass, particularly preferably not more than 80% by mass, and more preferably not more than 70% by mass. When the content is as described above, it becomes easy to adjust the aforementioned oxygen atomic ratio R ₁₀₀ to the aforementioned range in the formed adhesive layer.

Furthermore, when the acrylic copolymer (a1) contains both methyl acrylate and 2-methoxyethyl acrylate as monomer units constituting the polymer, methyl acrylate and 2-methoxyethyl acrylate The total value of the content is preferably at least 10% by mass, particularly preferably at least 30% by mass, and more preferably at least 50% by mass. In addition, the said total value is preferably 90 mass % or less, and is especially preferably 85 mass % or less. When the said total value exists in these ranges, in the adhesive layer formed, it becomes easy to adjust the said oxygen atomic ratio _R100 to the said range.

Furthermore, when the acrylic copolymer (a1) contains methoxyethylene glycol acrylate as a monomer unit constituting the polymer, the content of methoxyethylene glycol acrylate is 10% by mass or more. Preferably, more than 30% by mass is especially preferred. Furthermore, the content of methoxyethylene glycol acrylate is preferably at most 90% by mass, and particularly preferably at most 85% by mass. When the content is as described above, it becomes easy to adjust the aforementioned oxygen atomic ratio R ₁₀₀ to the aforementioned range in the formed adhesive layer.

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

Examples of functional group-containing monomers that are constituent units of the acrylic copolymer (a1) include polymerizable double bonds in the molecule, and functional groups such as hydroxyl, carboxyl, amino, substituted amino, and epoxy groups. Among them, at least one of hydroxyl group-containing monomers, amino group-containing monomers and substituted amino group-containing monomers is preferred.

As examples of the above hydroxyl-containing monomers, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (meth)acrylate, base) 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc., and these materials may be used alone or in combination of two or more.

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

In addition, as examples of the above-mentioned carboxyl group-containing monomers, for example, ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid, etc. can be listed, and the above-mentioned materials can be They can be used alone or in combination of two or more. However, the acrylic copolymer (a1) preferably does not contain a carboxyl group-containing monomer. Since the acrylic copolymer (a1) does not contain a carboxyl group-containing monomer, the adjustment of the water contact angle becomes easier.

In the acrylic copolymer (a1), the content of the structural unit derived from the above-mentioned functional group-containing monomer is preferably at least 1% by mass, particularly preferably at least 5% by mass, and at least 10% by mass. for better. Furthermore, in the acrylic copolymer (a1), the content of the structural unit derived from the functional group-containing monomer is preferably at most 35% by mass, particularly preferably at most 30% by mass.

As the (meth)acrylate monomer constituting the acrylic copolymer (a1), in addition to alkyl (meth)acrylates having 1 to 20 carbon atoms in the alkyl group, for example, those having Monomers of alicyclic structure (monomers containing alicyclic structure) are preferred.

As the alkyl (meth)acrylate, especially an alkyl (meth)acrylate having an alkyl group having 1 to 18 carbon atoms, for example, methyl methacrylate, ethyl (meth)acrylate, Propyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc. are preferable. The above materials may be used alone or in combination of two or more.

As the alicyclic structure-containing monomer, for example, cyclohexyl (meth)acrylate, dicyclopentyl (meth)acrylate, adamantyl (meth)acrylate, isocamphene (meth)acrylate ester, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, etc. are preferred. The above materials may be used alone or in combination of two or more.

Furthermore, the content of structural units derived from (meth)acrylate monomers or derivatives thereof in the acrylic copolymer (a1) is preferably at least 50% by mass, and preferably at least 60% by mass. It is especially preferable, and it is more preferable to contain 70 mass % or more. Furthermore, the content of the structural unit derived from the (meth)acrylate monomer or its derivatives in the acrylic copolymer (a1) is preferably 99% by mass or less, particularly preferably 95% by mass, It is more preferable to contain 90 mass % or less.

The acrylic copolymer (a1) can preferably be obtained by copolymerizing the above-mentioned hydrophilicity adjusting monomer, functional group-containing monomer, and (meth)acrylate monomer or its derivatives by a common method, but Dimethacrylamide, vinyl formate, vinyl acetate, styrene, etc. other than these monomers may also be copolymerized.

Active energy can be obtained by reacting the acrylic copolymer (a1) having the above-mentioned functional group-containing monomer unit with an unsaturated group-containing compound (a2) having a functional group that can be bonded to the above-mentioned functional group Radiation curable polymer (A).

The functional group which the unsaturated group containing compound (a2) has can be selected suitably according to the kind of the functional group of the functional group containing monomeric unit which acrylic-type copolymer (a1) has. For example, when the functional group of the acrylic copolymer (a1) is a hydroxyl group, an amino group, or a substituted amino group, as the functional group of the unsaturated group-containing compound (a2), an isocyanate group or a ring An oxygen group is preferable, and when the functional group possessed by the acrylic copolymer (a1) is an epoxy group, as the functional group possessed by the unsaturated group-containing compound (a2), an amino group, a carboxyl group or Aziridinyl is preferred.

Furthermore, in the above-mentioned unsaturated group-containing compound (a2), the active energy ray polymerizable carbon-carbon double bond contains at least 1 in 1 molecule, preferably 1 to 6, and contains 1 to 4 is better. Specific examples of such unsaturated group-containing compounds (a2) include 2-methacryloxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate, methyl Acryl isocyanate, allyl isocyanate, 1,1-(bisacryloxymethyl)ethyl isocyanate; propylene obtained by reacting a diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth)acrylate Acyl monoisocyanate compound; Acryl monoisocyanate compound obtained by reacting a diisocyanate compound or polyisocyanate compound with a polyol compound and hydroxyethyl (meth)acrylate; glycidyl (meth)acrylate; (form base) acrylic acid, 2-(1-aziridinyl)ethyl (meth)acrylate, 2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline, etc.

Relative to the number of moles of the functional group-containing monomer of the above-mentioned acrylic copolymer (a1), the ratio of the above-mentioned unsaturated group-containing compound (a2) used is preferably 50 mole % or more, and 60 mole % % or more is particularly good, and more than 70 mol% is better. Furthermore, relative to the number of moles of the functional group-containing monomer of the above-mentioned acrylic copolymer (a1), the ratio of the above-mentioned unsaturated group-containing compound (a2) used is preferably 95 mole % or less, and Less than 93 mol% is particularly preferred, and less than 90 mol% is more preferred.

The reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2) can be determined according to the functional groups of the acrylic copolymer (a1) and the unsaturated group-containing compound (a2). The combination of the functional groups, the reaction temperature, pressure, solvent, time, whether to use a catalyst, and the type of catalyst are appropriately selected. Thereby, the functional group present in the acrylic copolymer (a1) reacts with the functional group in the unsaturated group-containing compound (a2), and the unsaturated group is introduced into the side of the acrylic copolymer (a1). chain to obtain an active energy ray-curable polymer (A).

The weight average molecular weight (Mw) of the active energy ray-curable polymer (A) thus obtained is preferably at least 10,000, particularly preferably at least 150,000, and more preferably at least 200,000. In addition, this weight average molecular weight (Mw) is preferably 1,500,000 or less, and particularly preferably 1,000,000 or less. In addition, in this specification, a weight average molecular weight (Mw) is a standard polystyrene conversion value measured by gel permeation chromatography (GPC).

Even when the adhesive composition in this embodiment contains an active energy ray-curable polymer called an active energy ray-curable polymer (A), the adhesive composition may further contain an active energy ray-curable polymer (A). Energy ray curable monomer and/or oligomer (B).

As the active energy ray-curable monomer and/or oligomer (B), for example, polyhydric alcohols, esters of (meth)acrylic acid, and the like 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, neopentylthritol tri(meth)acrylate, neopentylthritol tetra(meth)acrylate, dipenteoerythritol hexa(meth)acrylate ester, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dimethylol tricyclo Multifunctional acrylates such as decane di(meth)acrylate, polyester oligo(meth)acrylate, urethane oligo(meth)acrylate, etc.

When the active energy ray-curable monomer and/or oligomer (B) and the active energy ray-curable polymer (A) are formulated simultaneously, the active energy ray-curable polymer (A) ), and the content of the active energy ray-curable monomer and/or oligomer (B) in the adhesive composition is preferably more than 0 parts by mass, particularly preferably 60 parts by mass or more. In addition, the said content is preferably 250 mass parts or less with respect to 100 mass parts of active energy ray-curable polymer (A), and it is especially preferable to be 200 mass parts or less.

Here, when ultraviolet rays are used as the active energy rays for curing the active energy ray-curable adhesive, the adhesive composition in the present embodiment preferably contains a photopolymerization initiator (C). By using this photopolymerization initiator (C), polymerization hardening time and light exposure amount can be reduced.

Specific examples of the photopolymerization initiator (C) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin Inin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone (2,4-diethylthioxanthone), 1-hydroxyl ring Hexyl phenyl ketone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzil, dibenzyl, diacetyl, β-chloroanthracene Quinone, (2,4,6-trimethylbenzyldiphenyl)phosphine oxide, 2-benzothiazole-N,N-diethyldithiocarbamate, oligo{2-hydroxy- 2-methyl-1-[4-(1-propenyl)phenyl]acetone}, 2,2-dimethoxy-1,2-diphenylethan-1-one, etc. These materials may be used alone or in combination of two or more.

With respect to 100 parts by mass of the active energy ray-curable polymer (A) (when the active energy ray-curable monomer and/or oligomer (B) is formulated, the active energy ray-curable polymer ( The total amount of A) and the active energy ray-curable monomer and/or oligomer (B) is 100 parts by mass), and the content of the photopolymerization initiator (C) in the adhesive composition is 0.1 part by mass or more Preferably, more than 0.5 parts by mass is particularly preferred. Furthermore, with respect to 100 parts by mass of the active energy ray-curable polymer (A) (in the case of preparing an active energy ray-curable monomer and/or oligomer (B), the active energy ray-curable The total amount of the polymer (A) and the active energy ray-curable monomer and/or oligomer (B) is 100 parts by mass), the above-mentioned content is preferably 10 parts by mass or less, and particularly preferably 6 parts by mass or less .

The adhesive composition according to the present embodiment preferably contains an additive (D) for adjusting the ratio of oxygen atoms in the adhesive layer. Examples of such additives include active energy ray-polymerizable branched polymers, branched polymers, and epoxy resins, among which the ratio of oxygen atoms in the adhesive layer can be easily adjusted to a desired range. From an internal point of view, it is preferable to use an active energy ray polymerizable branched polymer.

The active energy ray polymerizable branched polymer is a kind of active energy ray polymerizable compound, and means a polymer having an active energy ray polymerizable group and a branched structure. Since the adhesive layer in this embodiment is formed of an adhesive composition containing an active energy ray-polymerizable branched polymer, it becomes easy to analyze the oxygen atomic ratio measured by X-ray photoelectron spectroscopy on the adhesive surface. R ₀ is adjusted to be 28 atomic % or less. The reason for this is considered to be as described below, but is not limited thereto. When an adhesive layer is formed using an adhesive composition containing an active energy ray polymerizable branched polymer, the active energy ray polymerizable branched polymer tends to be biased toward the surface side of the adhesive layer. Therefore, in the formed pressure-sensitive adhesive layer, the content of the active energy ray-polymerizable branched polymer increases in the portion closer to the surface than the inside. Here, since the active energy ray-polymerizable branched polymer itself is a component having a relatively small ratio of oxygen atoms, the more adhesive surfaces of the active energy ray-polymerizable branched polymer exist, the easier it becomes to achieve a concentration of 28 atomic % or less. Oxygen atomic ratio.

Furthermore, since the active energy ray-polymerizable branched polymer has an active energy ray-polymerizable group, when the sheet for workpiece processing is irradiated with active energy rays, the active energy ray-polymerizable branched polymers may interact with each other or with active energy. The polymerization reaction between the radiation-polymerizable branched polymer and the component having the active energy ray-polymerizable group can be carried out, thereby, the migration of the active energy ray-polymerizable branched polymer to the processed workpiece can be suppressed, and after the active energy ray irradiation The final adhesive layer is more cured, and it becomes easy and effective to separate the processed workpiece from the workpiece processing sheet.

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

The weight average molecular weight of the active energy ray polymerizable branched polymer is preferably at least 1,000, particularly preferably at least 3,000. Furthermore, the weight average molecular weight is preferably at most 100,000, and particularly preferably at most 30,000. With the weight average molecular weight within the above range, it becomes easy to adjust the oxygen atomic ratio R ₀ measured by X-ray photoelectron spectroscopy on the adhesive surface to 28 atomic % or less.

With respect to 100 parts by mass of the active energy ray-curable polymer (A) (when the active energy ray-curable monomer and/or oligomer (B) is formulated, the active energy ray-curable polymer ( The total amount of A) and the active energy ray-curable monomer and/or oligomer (B) is 100 parts by mass), and the content of the additive (D) in the adhesive composition is preferably 0.05 parts by mass or more. 0.1 part by mass or more is particularly preferred. Furthermore, with respect to 100 parts by mass of the active energy ray-curable polymer (A) (in the case of preparing an active energy ray-curable monomer and/or oligomer (B), the active energy ray-curable The total amount of the polymer (A) and the active energy ray-curable monomer and/or oligomer (B) is 100 parts by mass), and the above-mentioned content is preferably at most 1 part by mass, particularly preferably at most 0.5 part by mass. When the content of the additive (D) is within the above range, it becomes easy to adjust the oxygen atomic ratio in the adhesive layer to be within a desired range.

The adhesive composition of this embodiment can also mix|blend other components suitably besides the components demonstrated above. As other components, an active energy ray non-curable polymer component or an oligomer component (E), a crosslinking agent (F), etc. are mentioned, for example.

Examples of the active energy ray non-curable polymer component or oligomer component (E) include polyacrylate, polyvinyl ester, polyurethane, polycarbonate, polyolefin, etc., and the weight average molecular weight (Mw) It is better to be 30-2.5 million polymers or oligomers. By blending this component (E) in the active energy ray-curable adhesive, the adhesiveness and peelability before curing, the strength after curing, the adhesiveness with other layers, the storage stability, and the like can be improved. The compounding quantity of this component (E) is not specifically limited, It can set suitably within the range which exceeds 0 mass parts and is 50 mass parts or less with respect to 100 mass parts of active energy ray-curable polymer (A). .

As the crosslinking agent (F), a polyfunctional compound having reactivity with a functional group contained in components such as the active energy ray-curable polymer (A) 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, and metal chelate compounds. , metal salts, ammonium salts, reactive phenolic resins, etc.

The compounded amount of the crosslinking agent (F) is preferably at least 0.01 parts by mass, particularly preferably at least 3 parts by mass, based on 100 parts by mass of the active energy ray-curable polymer (A). In addition, the compounding quantity of a crosslinking agent (F) is preferably 20 mass parts or less with respect to 100 mass parts of active energy ray-curable polymer (A), and is especially preferably 17 mass parts or less.

Next, in the following, the adhesive layer in this embodiment is composed of an adhesive including an active energy ray non-curable polymer component and a monomer and/or oligomer having at least one active energy ray curable group Describe the situation in which things are formed.

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

As the monomer and/or oligomer having at least one active energy ray-curable group, the same thing as the above-mentioned component (B) can be selected. Regarding the compounding ratio of the active energy ray non-curable polymer component and the monomer and/or oligomer having at least one active energy ray curable group, relative to 100 parts by mass of the active energy ray non-curable polymerization As a material component, monomers and/or oligomers having at least one active energy ray-curable group are preferably at least 1 part by mass, particularly preferably at least 60 parts by mass. Furthermore, with regard to this compounding ratio, 200 parts by mass of monomers and/or oligomers having at least one active energy ray-curable group are used with respect to 100 parts by mass of the active energy ray non-curable polymer component. The following is preferable, and 160 mass parts or less is especially preferable.

In this case, a photopolymerization initiator (C), an additive (D), a crosslinking agent (F), and the like can be appropriately prepared in the same manner as described above.

The adhesive layer is preferably at least 1 μm, particularly preferably at least 5 μm. Furthermore, the thickness is preferably 50 μm or less, and particularly preferably 40 μm or less. With the thickness of the adhesive layer within the above range, it becomes easy to achieve the required adhesion to the workpiece.

(3) Peeling sheet According to the workpiece processing sheet of this embodiment, until the adhesive surface in the adhesive layer is attached to the workpiece, in order to protect the surface, a release sheet may be laminated on the surface. The structure of the peeling sheet is optional, and for example, a plastic film (plastic film) is peeled with a peeling agent or the like. Specific examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polypropylene, polyethylene, etc. and other polyolefin films. As the release agent, polysiloxanes, fluorines, long-chain alkanes, etc. can be used, and among them, polysiloxanes that are cheap and can obtain stable performance are preferable. The thickness of the release sheet is not particularly limited, but is usually not less than 20 μm and not more than 250 μm.

(4) Other components According to the workpiece processing sheet of this embodiment, the adhesive layer may be laminated on the adhesive surface in the adhesive layer. In this case, since the workpiece processing sheet according to the present embodiment includes the adhesive layer as described above, it can be used as a dicing/die bonding sheet. In this workpiece processing sheet, the workpiece is attached to the surface of the adhesive layer opposite to the adhesive layer, and by cutting the workpiece together with the adhesive layer, it is possible to obtain laminated and divided adhesives. layers of wafers. With the divided adhesive layer, the chip can be easily fixed on the object on which the chip will be installed. As the material constituting the adhesive layer, it is preferable to use a material containing a thermoplastic resin and a low molecular weight thermosetting adhesive component, a material containing a B-stage (semi-cured) thermosetting adhesive component, or the like.

Furthermore, according to the workpiece processing sheet of this embodiment, the protective film forming layer may be laminated on the adhesive surface in the adhesive layer. In this case, according to the sheet for workpiece processing of this embodiment, it can be used as a sheet|seat for protective film formation and dicing. In this workpiece processing sheet, the workpiece is attached to the surface of the protective film forming layer on the opposite side to the adhesive layer, and by cutting the workpiece together with the protective film forming layer, it is possible to obtain laminated and divided sheets. Wafer with protective film forming layer. As the workpiece, a workpiece having a circuit formed on one surface is preferably used, and in this case, the protective film forming layer is usually laminated on the surface opposite to the surface on which the circuit is formed. The divided protective film forming layer can form a protective film having sufficient durability on a wafer by curing for a predetermined time. The protective film forming layer is preferably composed of an uncured curable adhesive.

In addition, the workpiece processing sheet according to the embodiment of the present application is a workpiece processing sheet in which the oxygen atomic ratio R ₀ and the oxygen atomic ratio R ₁₀₀ are each within the aforementioned range, and the above-mentioned adhesive layer is laminated on the adhesive layer. Or in the case of a protective film forming layer, the oxygen atomic ratio R ₀ and the oxygen atomic ratio R ₁₀₀ may be within the aforementioned ranges for the adhesive layer before laminating these layers.

3. Manufacturing method of sheet for workpiece processing The manufacturing method of the workpiece processing sheet according to this embodiment is not particularly limited, but the workpiece processing sheet according to this embodiment is preferably manufactured by laminating an adhesive layer on one side of a base material.

A known method can be used for laminating the adhesive layer on one side of the substrate. For example, it is preferable to transfer the pressure-sensitive adhesive layer formed on the release sheet to one side of the substrate. In this case, a coating solution containing the adhesive composition constituting the adhesive layer and, if necessary, a solvent or a dispersion medium can be prepared and coated with a die coater or curtain machine, spray (spray) coater, slit (slit) coater, knife (knife) coater, etc., to coat the peeled surface of the release sheet (hereinafter sometimes referred to as "peeled surface") The above coating solution is used to form a coating film, and by drying the coating film, an adhesive layer is formed. The properties of the coating solution are not particularly limited as long as it can be applied, and may contain components for forming the adhesive layer as solutes or as dispersoids. The release sheet in this laminate can also be peeled off as a process material, or can also be used to protect the adhesive surface of the adhesive layer until the workpiece is attached to the workpiece processing sheet.

In the case where the coating solution used to form the adhesive layer contains a crosslinking agent, by changing the above-mentioned drying conditions (temperature, time, etc.), or by additionally applying heat treatment, the active energy ray curability in the coating film can be improved. The crosslinking reaction between the polymer (A) or the active energy ray non-curable polymer and the crosslinking agent is carried out, and then a crosslinked structure is formed in the adhesive layer according to a desired density. In order to fully carry out this crosslinking reaction, after the adhesive is laminated on the base material by the above method, etc., it can also be carried out on the obtained workpiece processing sheet, for example, at 23°C and a relative humidity of 50%. Let stand in the environment for several days and so on.

Instead of transferring the adhesive layer formed on the release sheet to one side of the substrate as described above, the adhesive layer may be directly formed on the substrate. In this case, the coating solution for forming the aforementioned adhesive layer is applied on one side of the substrate to form a coating film, and by drying this coating film, the adhesive layer is formed.

4. How to use the sheet for workpiece processing According to the sheet for workpiece processing of this embodiment, it can be used for the processing of a workpiece. That is, after the workpiece is attached to the adhesive surface of the workpiece processing sheet according to the present embodiment, the workpiece can be processed on the workpiece processing sheet. Corresponding to the above processing, the workpiece processing sheet according to this embodiment can be used as a back ground sheet, a dicing sheet, an expanded sheet, a pickup sheet, and the like. Here, examples of the workpiece include semiconductor components such as a semiconductor wafer and a semiconductor package, and glass components such as a glass plate.

Furthermore, when the workpiece processing sheet according to this embodiment includes the adhesive layer, the workpiece processing sheet can be used as a dicing/die bonding sheet. Furthermore, when the workpiece processing sheet according to this embodiment is provided with the aforementioned protective film forming layer, this workpiece processing sheet can be used as a protective film forming and dicing sheet.

According to the workpiece processing sheet according to the present embodiment, the oxygen atomic ratio R measured by X-ray photoelectron spectroscopy is between ₁₀₀ and 100 nm at a position within the adhesive layer at a depth of 100 nm from the adhesive surface. Within the aforementioned range, even when the adhesive constituting the adhesive layer adheres to the workpiece after processing, the adhesive can be removed favorably by running water. Also, with the oxygen atomic ratio _R0 measured by X-ray photoelectron spectroscopy on the adhered surface being within the aforementioned range, it becomes possible to easily separate processed workpieces. Therefore, the workpiece processing sheet according to the present embodiment is suitable for processing using running water, and is particularly suitable for cutting while supplying running water to the cutting portion. That is, the sheet for workpiece processing according to this embodiment is suitable for use as a dicing sheet.

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

[Manufacturing method of processed workpiece] A method of manufacturing a processed workpiece according to an embodiment of the present invention, which includes: a step of bonding the surface of the adhesive layer of the sheet for workpiece processing that is opposite to the base material to the workpiece; by A processing step in which the workpiece is processed on the workpiece processing sheet to obtain a processed workpiece laminated on the workpiece processing sheet; the adhesive layer is irradiated with active energy rays to cure the adhesive layer, and the workpiece processing sheet an irradiating step of reducing the adhesion of the material to the processed workpiece; and a separation step of separating the processed workpiece from the sheet for workpiece processing after irradiation with active energy rays.

In the workpiece processing sheet used in the method of manufacturing a processed workpiece according to the present embodiment, even when the adhesive constituting the adhesive layer is attached to the processed workpiece, it can be adhered to the processed workpiece by flowing water. Adhesives are removed well and the finished workpieces can be separated easily and well. Therefore, according to the method of manufacturing a processed workpiece according to this embodiment, it becomes possible to efficiently manufacture a processed workpiece.

Each step in the manufacturing method of the machined workpiece of this embodiment will be described below.

(1) Fitting step In the bonding step, the workpiece and the sheet for workpiece processing can be bonded by a conventionally known method. In addition, when the workpiece is cut in the subsequent processing step, on the surface of the adhesive layer side of the sheet for processing the workpiece, the area around the outside of the area where the ring frame is attached to the workpiece is defined as good. Furthermore, the workpiece used may be a required workpiece corresponding to the finished workpiece to be manufactured, and the aforementioned workpiece may be used as a specific example.

(2) Processing steps In the processing step, the required processing can be performed on the workpiece, for example, back grinding, cutting, etc. can be performed. These processes can be performed by conventionally known methods.

In addition, in the above processing, when blade cutting is performed using a rotating blade, generally a part of the adhesive layer in the workpiece processing sheet is cut at the same time as the workpiece. At this time, the adhesive constituting the adhesive layer may be rolled up by the blade and adhere to the finished workpiece. However, the sheet for workpiece processing used in the manufacturing method of the processed workpiece of this embodiment can satisfactorily remove the adhering adhesive by running water as described above. From this point of view, the processing steps of the present embodiment are suitable for dicing, especially blade dicing using a rotating blade.

(3) Irradiation steps In the irradiation step, the irradiation conditions of the active energy rays are not limited as long as the adhesion of the workpiece processing sheet to the processed workpiece can be reduced to a desired level, and can be performed based on conventionally known methods. The type of active energy rays to be used includes, for example, ionizing radiation, that is, X-rays, ultraviolet rays, electron beams, etc. Among them, ultraviolet rays that are relatively easy to introduce into irradiation equipment are preferable.

(4) Separation step In the separation step, separation is carried out according to the type of processing and the method corresponding to the obtained processed workpiece. For example, when dicing is performed as processing and wafers formed by dividing the workpiece are obtained by the dicing, the obtained wafers are picked up from the workpiece processing sheet one by one using a conventionally known pick-up device. Furthermore, in order to facilitate picking, the workpiece processing sheet may also be expanded so that the processed workpieces are separated from each other.

(5) Others In the method of manufacturing a processed workpiece according to this embodiment, steps other than the above steps may be provided. For example, after the bonding step, a conveying step of conveying the obtained laminate of the workpiece and workpiece processing sheet to a predetermined position, or a storage step of storing the laminate for a predetermined period may be provided. Furthermore, after the separation step, a mounting step of mounting the obtained processed workpiece on a predetermined base or the like may be provided.

The embodiments described above are described for easy understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above-mentioned embodiments also covers all design changes and equivalents belonging to the technical scope of the present invention.

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

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

[Example 1] (1) Preparation of adhesive composition The acrylic copolymer obtained by copolymerizing 20 parts by mass of methyl acrylate, 60 parts by mass of 2-methoxyethyl acrylate, and 20 parts by mass of 2-hydroxyethyl acrylate, with respect to 100 grams of This acrylic copolymer is reacted with 21.4 g of methacryloxyethyl isocyanate (MOI) (equivalent to 80 mole % relative to the mole number of 2-hydroxyethyl acrylate) to obtain active energy rays curable polymer. The weight average molecular weight (Mw) of this active energy ray-curable polymer was measured by the method described later, and was 600,000.

100 parts by mass of the obtained active energy ray-curable polymer (calculated as solid content, the same applies hereinafter), 3 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name: "IRGACURE 184"), 9.32 parts by mass of toluene diisocyanate (manufactured by Tosoh Corporation, product name "Coronate L") as a crosslinking agent, 0.18 parts by mass of an active energy ray polymerizable branched polymer (Nissan Chemical Industry Co., Ltd. manufactured, product name "OD-007", weight average molecular weight: 14000), and mixed in a solvent to obtain an adhesive composition.

(2) Formation of adhesive layer For a release sheet (manufactured by Lintec, product name "SP-PET") formed by forming a silicone-based release agent layer on one side of a polyethylene terephthalate film with a thickness of 38 μm 381031"), apply the above-mentioned adhesive composition, and dry it by heating, then place it at 23°C and 50%RH for 7 days to mature, and form a 5μm-thick film on the release sheet. Adhesive layer.

(3) Production of sheets for workpiece processing By adhering the surface of the adhesive layer formed in the above step (2) on the opposite side to the release sheet, and one side of an ethylene-methacrylic acid copolymer (EMAA) film with a thickness of 80 μm as a base material, to each other combined to obtain a sheet for workpiece processing.

Here, the aforementioned weight average molecular weight (Mw) is a standard polystyrene-equivalent weight average molecular weight measured using gel permeation chromatography (GPC) (GPC measurement).

[Example 2 and Comparative Examples 1 to 3] A sheet for workpiece processing was produced in the same manner as in Example 1 except that the composition of the acrylic copolymer, the content of the crosslinking agent, and the content of the additives were changed as shown in Table 1.

[Test Example 1] (Measurement of Oxygen Atomic Ratio) The peeling sheet was peeled off from the workpiece processing sheet produced in the examples and comparative examples, and the exposed adhesive was measured using an X-ray photoelectron spectrometer (manufactured by ULVAC‧PHI, product name "PHI Quantera SXM") The oxygen atomic ratio (%) of the exposed surface (adhesive surface) of the layer and the oxygen atomic ratio (%) in the adhesive layer at a depth of 100nm from the exposed surface are defined as "0nm position" respectively. Oxygen atomic ratio (%) and "100nm position" oxygen atomic ratio (%). The results are shown in Table 1.

[Test Example 2] (Measurement of Adhesive Force) The release sheet was peeled off from the workpiece processing sheets produced in Examples and Comparative Examples, and the exposed surface of the exposed adhesive layer was superimposed on the mirror surface of a mirror-polished 6-inch silicon wafer, and a 2 kg roller was used The roller (roller) rolled back and forth once to apply a load to make the two adhere to each other, and then stand still for 20 minutes to obtain a sample for adhesion measurement.

For this sample for adhesion measurement, the workpiece processing sheet was peeled from the silicon wafer at a peel rate of 300mm/min and a peel angle of 180°, and measured by the 180° peel method in accordance with JIS Z0237:2009. Adhesion to silicon wafer (mN/25mm). The results are shown in Table 1 as the adhesive force before ultraviolet irradiation (before UV).

[Test Example 3] (Evaluation of Removability of Adhesive) The release sheet was peeled off from the workpiece processing sheet produced in the examples and comparative examples, and a tape mounter (manufactured by Lintec Corporation, product name "Adwill RAD2500m/12") was used to place the adhesive on the exposed surface. On the exposed surface of the agent layer, attach the polished surface of a #2000-polished 6-inch silicon wafer (thickness: 150 μm). Next, using a dicing device (manufactured by Disco, product name "DFD-6361"), dicing was performed by cutting from the side of the 6-inch silicon wafer while supplying running water to the dicing portion under the following dicing conditions.

＜Cutting conditions＞ ‧Cutting device: DFD-6361 manufactured by Disco ‧Blade: NBC-2H 2050 27HECC made by Disco ‧Blade width: 0.025～0.030mm ‧Infeed amount of blade: 0.640～0.760mm ‧Blade speed: 50000rpm ‧Cutting speed: 20mm/sec ‧Cutting depth: 15μm from the surface of the adhesive layer side in the workpiece processing sheet ‧Flowing water supply: 1.0L/min ‧Flowing water temperature: room temperature ‧Cutting size: 10mm×10mm

Twenty of the wafers obtained by the above dicing were separated from the workpiece processing sheet, and observed with the naked eye to confirm whether or not the adhesive adhered to these wafers. After that, the removability of the adhesive was evaluated based on the following criteria. The results are shown in Table 1. ◯: The number of wafers to which the adhesive was adhered was zero. ╳: One or more wafers adhered to the adhesive.

[Test Example 4] (Evaluation of Separability) Using the workpiece processing sheets produced in the examples and comparative examples, they were cut in the same manner as in Test Example 3. After the cutting is completed, use an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2000") to irradiate the surface of the workpiece processing sheet with ultraviolet rays (UV) (illuminance: 230mW/cm ² , light intensity: 190mJ/cm ² ), to cure the adhesive layer. After that, all the obtained wafers are picked up from the workpiece processing sheet. At this time, use needles to push up from the surface of the workpiece processing sheet opposite to the surface to which the glass wafer is attached (Number of needles: 4, Push up speed: 50mm/sec, Push up height: 0.5mm ). Based on the pickup situation at this time, the separability at the time of separating the wafer from the workpiece processing sheet was evaluated according to the following criteria. The results are shown in Table 1. ○: Can be picked up without any problem. ╳: The wafer cannot be separated, or the wafer may be broken, so the pickup cannot be performed satisfactorily.

In addition, details such as abbreviations described in Table 1 are as follows. BA: butyl acrylate MMA: methyl methacrylate MA: methyl acrylate 2MEA: 2-methoxyethyl acrylate HEA: 2-Hydroxyethyl Acrylate

[Table 1]

As can be seen from Table 1, according to the workpiece processing sheet obtained in the examples, the adhesive can be well removed by running water, and the processed workpiece can be well separated. [industrial availability]

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

none.

none.

Claims (6)

A sheet for workpiece processing, which is a sheet for workpiece 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 The energy ray-curable adhesive is an adhesive formed of an adhesive composition containing an active energy ray-polymerizable branched polymer. On the surface of the adhesive layer opposite to the substrate, X-ray photoelectron spectroscopy The oxygen atomic ratio _R0 measured by analysis is 28 atomic % or less, and at a position within the adhesive layer at a depth of 100 nm from the surface of the adhesive layer opposite to the base material, using The oxygen atomic ratio R ₁₀₀ measured by X-ray photoelectron spectroscopy is 20 atomic % or more and 29 atomic % or less. The workpiece processing sheet as described in claim 1, wherein the value of the aforementioned oxygen atomic ratio R ₀ is greater than the value of the aforementioned oxygen atomic ratio R ₁₀₀ , and the reduction rate of the oxygen atomic ratio is based on the following formula (1) (%)={(oxygen atomic ratio R ₀ −oxygen atomic ratio R ₁₀₀ )/oxygen atomic ratio R ₀ }×100 (1) The calculated decrease rate of the oxygen atomic ratio is 0% or more and 15% or less. The workpiece processing sheet as described in item 1 of the scope of the patent application, wherein the aforementioned active energy ray polymerizable branched polymer is obtained by the following method: a unit having two or more free radical polymerizable double bonds in the molecule A polymer with a branched structure obtained by polymerizing a monomer with an active hydrogen group and a free radical polymerizable double bond in the molecule, and a monomer with a free radical polymerizable double bond in the molecule, and A compound having a functional group capable of reacting with an active hydrogen group to form a bond in the molecule and at least one free radical polymerizable double bond is reacted. The workpiece processing sheet according to claim 1 of the patent claims, wherein the adhesive composition contains an acrylic copolymer having a monomer unit containing a functional group, and an acrylic copolymer having a functional group bonded to the functional group. An active energy ray-curable polymer obtained by reacting a compound containing an unsaturated group, and the aforementioned acrylic copolymer contains At least one kind of alcohol (meth)acrylate and methoxyethylene glycol (meth)acrylate is used as a monomer unit constituting the polymer. The workpiece processing sheet as described in item 1 of the scope of the patent application is a cutting sheet. A method for manufacturing a processed workpiece, which includes: connecting the surface of the adhesive layer on the opposite side to the base material of the workpiece processing sheet described in any one of claims 1 to 5 of the patent application with the workpiece Laminating step of bonding; processing the aforementioned workpiece on the aforementioned workpiece processing sheet to obtain a processed workpiece laminated on the aforementioned workpiece processing sheet; irradiating the aforementioned adhesive agent layer with activity An energy ray irradiating step of curing the adhesive layer so that the adhesion of the sheet for processing the workpiece to the processed workpiece is reduced; and the sheet for processing the workpiece after irradiating the processed workpiece with active energy rays Separation steps for material separation.