TW202100687A - Pressure-sensitive adhesive sheet, method for producing pressure-sensitive adhesive sheet, and method for producing semiconductor device - Google Patents

Abstract

The present invention pertains to a pressure-sensitive adhesive sheet comprising: a substrate (Y); and a pressure-sensitive adhesive layer (X1) containing a polymer of energy ray-polymerizable components and thermally expandable particles, wherein the polymer is obtained by irradiating, with energy rays, a polymerizable composition which contains, as the energy ray-polymerizable components, a monomer (a1) having an energy ray-polymerizable functional group and a prepolymer (a2) having an energy ray-polymerizable functional group.

Description

Adhesive sheet, adhesive sheet manufacturing method and semiconductor device manufacturing method

The present invention relates to an adhesive sheet, an adhesive sheet manufacturing method, and a semiconductor device manufacturing method.

The adhesive sheet is not only used for semi-permanent fixing of components, but also used as a temporary fixation of a component to be processed or inspected when processing or inspecting building materials, interior materials, electronic parts, etc. (hereinafter also referred to as "attached body" ") when the temporary fixing sheet is used. For example, in the manufacturing process of semiconductor devices, temporary fixing sheets are used when processing semiconductor wafers.

In the manufacturing process of the semiconductor device, the semiconductor wafer is processed on the semiconductor wafer through a grinding step of thinning the thickness by grinding, a singulation step of cutting and separating and singulation, etc. At this time, the semiconductor wafer performs a predetermined process on the temporary fixing sheet in a temporarily fixed state. After the semiconductor wafers obtained by the specified processing are separated from the temporary fixing sheet, if necessary, the expansion step of expanding the distance between the semiconductor wafers, the re-arrangement step of arranging a plurality of semiconductor wafers at the expansion interval, and making the semiconductor wafers After the reversal step of the front and back reversal, it is mounted on the substrate. In each of the above steps, temporary fixing sheets suitable for individual applications can be used.

Patent Document 1 discloses a heat-peelable adhesive sheet for temporary fixation of electronic parts when a heat-expandable adhesive layer containing heat-expandable microspheres is provided on at least one side of a substrate. In the same literature, the heat-peelable adhesive sheet can be used for cutting electronic parts. Since it can secure a specified contact area to the object to be adhered, it can prevent chip scattering and other adhesion failures. After use, if the heat-expandable microspheres are heated to expand, the contact area with the object is reduced, and it can be easily peeled off. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 3594853

[The problem to be solved by the invention]

However, when mounting a semiconductor chip on a substrate, a step of attaching the semiconductor chip to the substrate through a thermosetting film-like adhesive called die-bonding film (hereinafter also referred to as "DAF") is adopted. DAF is attached to the semiconductor wafer or the side surface of a plurality of singulated semiconductor chips. It is divided into the same shape as the semiconductor wafer at the same time as the singulation of the semiconductor wafer or after it is attached to the semiconductor wafer. The DAF-attached semiconductor wafer obtained by singulation is adhered (die-bonded) to the substrate from the DAF side, and then the DAF is thermally cured to fix the semiconductor wafer and the substrate. At this time, until the DAF is attached to the substrate, it is necessary to maintain the property of bonding by pressure or heating.

The heat-peelable adhesive sheet disclosed in Patent Document 1 expands heat-expandable microspheres to form irregularities on the adhesive surface and peel off from the adherend. The adhesive sheet can reduce the contact area between the adhesive layer and the semiconductor chip by the formation of unevenness. Therefore, compared with the energy ray irradiation to harden the adhesive layer and reduce the adhesive force, the temporary fixing sheet has less usability. The strength of the force is separated from the body. However, when the semiconductor wafer with DAF is used as the substrate of the heat-peelable adhesive sheet, the heating during expansion of the thermally expandable microspheres results in the hardening of DAF before the die bonding, which reduces the adhesion of DAF to the substrate. Power situation. The decrease in the adhesive force of DAF causes a decrease in the reliability of the bonding between the semiconductor wafer and the substrate, so it is expected to be suppressed. On the other hand, in order to prevent the hardening of DAF before bonding, it is possible to heat and peel at a low temperature. When using a low expansion start temperature as the heat-expandable microspheres of the heat-peelable adhesive sheet, it is used in the manufacture of the adhesive sheet During the process, problems such as unintentional expansion of heat-expandable microspheres sometimes occur. As a result, the performance of the temporary fixing sheet may be impaired, such as a decrease in adhesive force, formation of a space during application (air between the adherend and the adhesive sheet), etc.

In order to suppress accidental expansion during the manufacturing process of the adhesive sheet, it is effective to omit the heating step in the manufacturing process of the adhesive sheet as much as possible. As one of the methods, it is considered to be a method of forming an adhesive layer by irradiating energy rays after forming a coating film using energy-ray polymerizable components to polymerize the energy-ray polymerizable components. The energy ray polymerizable component before polymerization has a low molecular weight and is easy to adjust the viscosity, so there is no need to use a diluent during coating, and the heating and drying step when forming the adhesive layer can be omitted. However, when an energy-ray polymerizable component is used for the formation of the adhesive layer, since its blending composition affects both the formability and performance of the adhesive layer, it is difficult for them to be an excellent overall.

The present invention was completed in view of the above-mentioned problems, to provide an adhesive layer that has good formability of the adhesive layer even when the adhesive layer is formed by an energy ray polymerizable component, and has sufficient adhesive force when temporarily fixed The purpose is an adhesive sheet that has excellent peelability during heat peeling, a method of manufacturing the adhesive sheet, and a method of manufacturing a semiconductor device using the adhesive sheet. [Means to solve the problem]

The present inventors found that by having a base material, and an adhesive layer with a polymer containing energy-ray polymerizable components and thermally expandable particles, the aforementioned polymer is compatible with monomers having energy-ray polymerizable functional groups and energy-ray polymerizable functional groups. The energy ray polymerizable component of the polymerizable functional group prepolymer, and the adhesive sheet of the polymer formed by the energy ray irradiation, can solve the above-mentioned problems. That is, the present invention relates to the following [1] to [15]. [1] An adhesive sheet comprising a substrate (Y), an adhesive layer (X1) with a polymer containing energy ray polymerizable components and thermally expandable particles, The aforementioned polymer as the aforementioned energy-ray polymerizable component is a polymerizable composition containing a monomer (a1) having an energy-ray polymerizable functional group and a prepolymer (a2) having an energy-ray polymerizable functional group, and is irradiated with energy Polymer made of thread. [2] The adhesive sheet as described in [1] above, wherein the component (a2) contains a prepolymer having two energy ray polymerizable functional groups and having the energy ray at both ends Polymerizable functional group. [3] The adhesive sheet as described in [1] or [2] above, wherein the mass average molecular weight (Mw) of the component (a2) is 10,000 to 350,000. [4] The adhesive sheet according to any one of [1] to [3] above, wherein in the polymerizable composition, the content ratio of the component (a2) and the component (a1) [(a2) /(a1)], 10/90～70/30 on the basis of quality. [5] The adhesive sheet according to any one of [1] to [4] above, wherein the polymerizable composition as the component (a1) contains a monomer having 3 or more energy-ray polymerizable functional groups body. [6] The adhesive sheet according to any one of the above [1] to [5], wherein the polymerizable composition as the component (a1) contains a monomer having an energy-ray polymerizable functional group and a hydroxyl group . [7] The adhesive sheet according to any one of the above [1] to [6], wherein the polymerizable composition as the component (a1) contains an energy-ray polymerizable functional group and an alicyclic hydrocarbon group The monomer. [8] The adhesive sheet according to any one of [1] to [7] above, wherein the thickness of the adhesive layer (X1) at 23° C. is 5 to 150 μm. [9] The adhesive sheet according to any one of [1] to [8] above, wherein the expansion start temperature (t) of the thermally expandable particles is 50 to 110°C. [10] The adhesive sheet as described in any one of [1] to [9] above, which has a substrate (Y) and an adhesive layer provided on a surface side of the substrate (Y) ( X1), and an adhesive layer (X2) provided on the other side of the substrate (Y). [11] A method for manufacturing an adhesive sheet, which is the method for manufacturing an adhesive sheet as described in any one of [1] to [10] above, characterized by The method of forming the adhesive layer (X1) includes the step of irradiating the polymerizable composition containing the energy-ray polymerizable component and the thermally expandable particles with energy rays to form the polymer of the energy-ray polymerizable component. [12] A method of manufacturing a semiconductor device, comprising: attaching a work object to the adhesive sheet as described in any one of [1] to [10] above, Perform one or more processing selected from grinding processing and singulation processing on the aforementioned processing object, After performing the aforementioned treatment, the step of heating the aforementioned adhesive sheet to above the aforementioned expansion starting temperature (t) to expand the adhesive layer (X1). [13] A method of manufacturing a semiconductor device, which includes the following steps 1A to 5A, Step 1A: A step of attaching an additional object to the adhesive layer (X2) of the adhesive sheet described in [10] above, and attaching a support to the adhesive layer (X1) of the adhesive sheet described above Step 2A: A step of performing one or more processing selected from grinding processing and singulation processing on the aforementioned processing object Step 3A: A step of attaching a thermosetting film with thermosetting properties to the surface opposite to the adhesive layer (X2) of the object to be processed Step 4A: The step of heating the adhesive sheet to a temperature above the expansion initiation temperature (t) and below 120°C to separate the adhesive layer (X1) from the support Step 5A: A step of separating the adhesive layer (X2) from the aforementioned object to be processed. [14] The method for manufacturing a semiconductor device as described in [13] above, wherein the adhesive layer (X2) is cured by irradiating energy rays to reduce the adhesive force, The aforementioned step 5A is a step of irradiating the adhesive layer (X2) with energy rays to harden the adhesive layer (X2) and separating the adhesive layer (X2) from the aforementioned object to be processed. [15] A method of manufacturing a semiconductor device, which includes the following steps 1B to 4B, Step 1B: A step of attaching an additional object to the adhesive layer (X1) of the adhesive sheet described in [10] above, and attaching a support to the adhesive layer (X2) of the adhesive sheet described above Step 2B: A step of performing one or more processing selected from grinding processing and singulation processing on the aforementioned processing object Step 3B: A step of attaching a thermosetting film with thermosetting properties to the surface opposite to the adhesive layer (X1) of the object to be processed Step 4B: A step of heating the adhesive sheet to a temperature above the expansion initiation temperature (t) and below 120°C to separate the adhesive layer (X1) from the object to be processed. [Invention Effect]

According to the present invention, it is possible to provide an adhesive layer with good formability even when the adhesive layer is formed by an energy ray polymerizable component, and has sufficient adhesive force when temporarily fixed, and can be peeled off by heating Adhesive sheet with excellent releasability in time, a method of manufacturing the adhesive sheet, and a method of manufacturing a semiconductor device using the adhesive sheet.

In this specification, the "active ingredient" refers to the ingredient from which the dilution solvent is removed among the ingredients contained in the target composition. In addition, in this specification, the mass average molecular weight (Mw) is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method, and specifically, is a value measured according to the method described in the examples.

In this specification, for example, "(meth)acrylic acid" means both "acrylic acid" and "methacrylic acid", and other similar terms are also the same. In addition, in this specification, the lower limit and the upper limit described in stages can be combined independently for the preferable numerical range (for example, the range of content, etc.). For example, from the description of "preferably 10 to 90, more preferably 30 to 60", it is also possible to combine "preferred lower limit value (10)" and "better upper limit value (60)" to be defined as " 10～60".

In this specification, the term "energy rays" means those having energy quantum in electromagnetic waves or charged particle rays, and examples thereof include ultraviolet rays, radiation rays, and electron beams. Ultraviolet rays can be irradiated by using, for example, electrodeless lamps, high-pressure mercury lamps, metal halide lamps, UV-LEDs, etc. as the ultraviolet source. The electron beam can be irradiated by an electron beam accelerator or the like. In this specification, the "energy ray polymerizability" means the property of polymerization by irradiation of energy rays.

In this specification, whether "layer" is "non-thermally expandable layer" or "thermally expandable layer" is judged as follows. When the layer to be judged contains heat-expandable particles, the layer is heat-treated at the expansion start temperature (t) of the heat-expandable particles for 3 minutes. When the volume change rate calculated by the following formula is less than 5%, the layer is judged to be a "non-thermally expandable layer", and when it is 5% or more, the layer is judged to be a "thermally expandable layer". Volume change rate (%)={(volume of the aforementioned layer after heat treatment-volume of the aforementioned layer before heat treatment)/volume of the aforementioned layer before heat treatment}×100 The layer that does not contain thermally expandable particles is designated as "non-thermally expandable layer".

In this specification, the "surface" of a semiconductor wafer and a semiconductor chip refers to the surface on which a circuit is formed (hereinafter also referred to as a "circuit surface"), and the "back" of a semiconductor wafer and a semiconductor chip refers to The side where no circuit is formed.

[Adhesive sheet] One aspect of the adhesive sheet of the present invention is an adhesive sheet having a substrate (Y), and an adhesive layer (X1) of a polymer containing energy ray polymerizable components and thermally expandable particles, and the polymer is used as the energy ray polymer The sexual component is the adhesion of the polymerizable composition containing the monomer (a1) with energy ray polymerizable functional group and the prepolymer (a2) with energy ray polymerizable functional group, and the polymer formed by irradiating energy rays Thin slices.

One aspect of the adhesive sheet of the present invention is that the heat-expandable particles contained in the adhesive layer (X1) are heated to a temperature above the expansion start temperature (t) to expand, and the adhesive layer (X1) is adhered The surface is uneven and peeled from the body. The adhesive sheet of one aspect of the present invention can reduce the contact area between the adhesive layer (X1) and the object due to the formation of the above-mentioned unevenness, and can significantly reduce the adhesion between the adhesive sheet and the object. Thereby, the adhesive sheet of one aspect of the present invention does not need to apply a peeling force during heat peeling, and can be peeled from the adhered body by the weight of the adhesive sheet or the adhered body. Specifically, for example, when the adhesive sheet of one aspect of the present invention is heated and peeled from the object to be adhered, the adhesive sheet side is turned downward, and the adhesive sheet is dropped from the object to be adhered by gravity. Peel off. In this specification, instead of applying a peeling force to the adhesive sheet, the state of the adhesive sheet being peeled from the adherend or peeling is referred to as "self-peeling". In addition, it defines such a nature as "self-stripping." As mentioned above, since the adhesive sheet of one aspect of the present invention reduces the contact area between the adhesive layer (X1) and the body during heat peeling, the adhesive layer is hardened by energy ray irradiation. Temporary fixing sheet with reduced adhesive force is excellent in self-peelability.

In addition, the polymer of the energy ray polymerizable component contained in the adhesive layer (X1) of the adhesive sheet of one aspect of the present invention is based on a monomer (a1) having an energy ray polymerizable functional group and The polymerizable composition of the energy-ray polymerizable functional group prepolymer (a2) is a polymer formed by irradiating energy rays. Since the energy-ray polymerizable component can become polymerizable after the coating film is formed, it is not necessary to use a high molecular weight adhesive resin and a solvent as the diluent when forming the coating film. As a result, when the adhesive layer (X1) is formed using the polymerizable composition, heating and drying to remove the solvent can be omitted, and unexpected expansion of the heat-expandable particles during heating and drying can be suppressed. In addition, the adhesive sheet of one aspect of the present invention uses at least two kinds of compounds having a monomer (a1) having an energy ray polymerizable functional group and a prepolymer (a2) having an energy ray polymerizable functional group In the formation of the adhesive layer, excellent formation of the adhesive layer is obtained, and sufficient adhesive force and excellent self-peelability are obtained. It is considered that the polymerizable composition with the above composition has a viscosity suitable for coating film formation, and the polymer formed by energy ray irradiation has a moderate cohesive force, thereby improving the balance between adhesive force and self-peelability.

Although the structure of the adhesive sheet of one aspect of the present invention may have a base material (Y) and an adhesive layer (X1), it may have a base material (Y) and an adhesive layer (X1) due to the application. ). For example, when the adhesive sheet of one aspect of the present invention is used in the processing of an adhered body, from the viewpoint of improving the processability of the adhered body, it is preferable to have the following configuration (that is, the structure of the double-sided adhesive sheet) , This structure has a substrate (Y), an adhesive layer (X1) provided on one side of the substrate (Y), and an adhesive layer provided on the other side of the substrate (Y) Agent layer (X2). By having this structure, the body can be attached to the adhesive layer on either side of the adhesive layer (X1) or the adhesive layer (X2), and it can be attached and supported on the other adhesive layer of either body. The object is fixed to the support through the adhesive sheet, and when the object is processed, the vibration of the object, the position shift, and the damage of the fragile object can be suppressed, and the processing accuracy and processing can be improved. speed. In the following description, unless otherwise stated, the so-called "double-sided adhesive sheet" means having a substrate (Y) and an adhesive layer (X1) provided on one side of the substrate (Y) , Adhesive sheet with the adhesive layer (X2) provided on the other side of the substrate (Y).

The adhesive sheet of one aspect of the present invention may have a release material on the adhesive surface of the adhesive layer (X1). In addition, when the adhesive sheet of one aspect of the present invention has a double-sided adhesive sheet configuration, it may have a release material on the adhesive surface of at least one of the adhesive layer (X1) and the adhesive layer (X2).

Next, referring to the drawings, the structure of the adhesive sheet of one aspect of the present invention will be described in more detail.

[Composition of adhesive sheet] As an adhesive sheet of one aspect of the present invention, an adhesive sheet 1a having an adhesive layer (X1) on a substrate (Y) as shown in FIG. 1(a) can be cited. Furthermore, the adhesive sheet of one aspect of the present invention, such as the adhesive sheet 1b shown in FIG. 1(b), can be placed on the adhesive surface of the adhesive layer (X1), and further constituted with the release material 10.

As another aspect of the adhesive sheet of the present invention, a structure having the above-mentioned double-sided adhesive sheet can be cited. As an adhesive sheet having such a structure, for example, a double-sided adhesive sheet having a structure in which a base material (Y) is sandwiched by an adhesive layer (X1) and an adhesive layer (X2) as shown in FIG. 2(a) 2a. In addition, the double-sided adhesive sheet 2b shown in Figure 2(b) can be further provided with a release material 10a on the adhesive surface of the adhesive layer (X1), and a release material on the adhesive surface of the adhesive layer (X2) The composition of 10b.

Furthermore, in the double-sided adhesive sheet 2b shown in Figure 2(b), the peeling force when the peeling material 10a is peeled from the adhesive layer (X1) and the peeling force when the peeling material 10b is peeled from the adhesive layer (X2) When it is the same degree, when both of the release materials are to be stretched and peeled to the outside, the adhesive layer may be broken with the two release materials, and peeling may occur. From the viewpoint of suppressing such a phenomenon, it is preferable to use two types of peeling materials designed so that the peeling force from the adhesive layer to which the two peeling materials 10a, 10b are stuck to each other is different.

As another type of adhesive sheet, it can be a double-sided adhesive sheet, which is attached to the double-sided adhesive sheet 2a shown in Figure 2(a), on the adhesive surface on one side of the adhesive layer (X1) and the adhesive layer (X2) It has a structure in which a release material laminated on both sides and subjected to a release treatment is wound into a roll.

The adhesive sheet of one aspect of the present invention may have other layers between the substrate (Y) and the adhesive layer (X1), or may not have other layers. In addition, when the adhesive sheet of one aspect of the present invention is the above-mentioned double-sided adhesive sheet, in addition to the above, it may have other layers between the base material (Y) and the adhesive layer (X2), or may not have other layers. However, it is preferable to directly laminate a layer on the side opposite to the adhesive surface of the adhesive layer (X1) to suppress swelling on this surface, and it is more preferable to directly laminate the substrate (Y).

＜Substrate (Y)＞ As a material for forming the substrate (Y), for example, resin, metal, paper, etc. can be cited, and it can be appropriately selected according to the application of the adhesive sheet of one aspect of the present invention.

Examples of resins include polyolefin resins such as polyethylene and polypropylene; vinyl-based resins such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, and ethylene-vinyl alcohol copolymer. Resins; Polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.; polystyrene; acrylonitrile-butadiene-styrene copolymer; Cellulose triacetate; polycarbonate; urethane resins such as polyurethane and acrylic modified polyurethane; polymethylpentene; polysulfite; polyether ether ketone; polyether Polyphenylene sulfide; polyimide resins such as polyetherimide and polyimide; polyimide resin; acrylic resin; fluorine resin, etc. Examples of metals include aluminum, tin, chromium, titanium, and the like. Examples of paper materials include thin leaf paper, medium-quality paper, high-quality paper, impregnated paper, coated paper, art paper, sulfuric acid paper, and transparent paper. Among these, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate are preferred.

These forming materials may be composed of one type, or two or more types may be used in combination. Examples of the substrate (Y) using two or more forming materials in combination include those in which paper materials are laminated with thermoplastic resins such as polyethylene, and those in which a metal layer is formed on the surface of a resin film or sheet containing resin. As a method of forming the metal layer, for example, a method of vapor-depositing a metal by a PVD method such as vacuum vapor deposition, sputtering, or ion plating, a method of attaching a metal foil with a general adhesive, and the like can be cited.

From the viewpoint of improving the interlayer adhesion between the base material (Y) and the other layers of the laminate, the surface of the base material (Y) can be subjected to surface treatment by oxidation, embossing, etc., and easy bonding treatment , Primer treatment, etc. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromic acid treatment (wet), hot air treatment, ozone irradiation treatment, ultraviolet irradiation treatment, and the like. Moreover, as a roughening method, a sandblasting method, a solvent processing method, etc. are mentioned, for example.

The base material (Y) is used as an additive for the base material together with the above resin, and may contain, for example, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, slip aids, anti-blocking agents, colorants, and the like. These additives for substrates may be used alone, or two or more of them may be used in combination. When the substrate (Y) contains the additive for the substrate together with the above-mentioned resin, the content of the individual additive for the substrate is preferably 0.0001-20 parts by mass, more preferably 0.001-10 parts by mass relative to 100 parts by mass of the above-mentioned resin.

The base material (Y) is preferably a non-thermally expandable layer. When the substrate (Y) is a non-thermally expandable layer, the volume change rate (%) of the substrate (Y) calculated from the above formula is less than 5%, preferably less than 2%, more preferably less than 1 %, more preferably less than 0.1%, and still more preferably less than 0.01%.

The base material (Y) may contain thermally expandable particles within a range that does not violate the purpose of the present invention, but preferably does not contain thermally expandable particles. When the substrate (Y) contains heat-expandable particles, the content should be as small as possible. Relative to the total mass (100% by mass) of the substrate (Y), it is preferably less than 3% by mass, more preferably less than 1 The mass% is more preferably less than 0.1 mass%, still more preferably less than 0.01 mass%, and still more preferably less than 0.001 mass%.

(Storage elastic modulus E'(23) of substrate (Y) at 23°C) Storage elastic modulus E'(23) of substrate (Y) at 23°C, preferably 5.0×10 ⁷ to 5.0×10 ⁹ Pa , More preferably 5.0×10 ⁸ to 4.5×10 ⁹ Pa, still more preferably 1.0×10 ⁹ to 4.0×10 ⁹ Pa. If the storage elastic modulus E'(23) of the base material (Y) is 5.0×10 ⁷ Pa or more, the expansion of the base material (Y) side of the adhesive layer (X1) can be effectively suppressed, and the adhesion can be improved Deformation resistance of the sheet. On the other hand, if the storage elastic modulus E'(23) of the base material (Y) is 5.0×10 ⁹ Pa or less, the workability of the adhesive sheet can be improved. In this specification, the storage elastic modulus E'(23) of the base material (Y) means the value measured by the method described in the examples.

(Storage elastic modulus E'(t) of the base material (Y) at the initial expansion temperature (t)) Storage elastic modulus E'(t) of the thermally expandable particles of the base material (Y) at the initial expansion temperature (t) , Preferably 5.0×10 ⁶ ～4.0×10 ⁹ Pa, more preferably 2.0×10 ⁸ ～3.0×10 ⁹ Pa, still more preferably 5.0×10 ⁸ ～2.5×10 ⁹ Pa. If the storage elastic modulus E'(t) of the base material (Y) is 5.0×10 ⁶ Pa or more, the expansion of the base material (Y) side of the adhesive layer (X1) can be effectively suppressed, and the adhesion can be improved Deformation resistance of the sheet. On the other hand, if the storage elastic modulus E'(t) of the base material (Y) is 4.0×10 ⁹ Pa or less, the workability of the adhesive sheet can be improved. In this specification, the storage elastic modulus E'(t) of the base material (Y) means the value measured by the method described in the examples.

(Thickness of base material (Y)) The thickness of the substrate (Y) is preferably 5 to 500 μm, more preferably 15 to 300 μm, and still more preferably 20 to 200 μm. If the thickness of the substrate (Y) is 5 μm or more, the deformation resistance of the adhesive sheet can be improved. On the other hand, if the thickness of the substrate (Y) is 500 μm or less, the handling of the adhesive sheet can be improved. In this specification, the thickness of the base material (Y) means the value measured by the method described in the examples.

＜Adhesive layer (X1)＞ The adhesive layer (X1) is a polymer containing energy ray polymerizable components and thermally expandable particles. The above-mentioned polymer, as the energy-ray polymerizable component, is prepolymerized with a monomer (a1) having an energy-ray polymerizable functional group (hereinafter also referred to as "(a1) component") and an energy-ray polymerizable functional group (A2) (hereinafter also referred to as "(a2) component") polymerizable composition (hereinafter also referred to as "polymerizable composition (x-1)"), polymer obtained by irradiating energy rays. In this specification, the term "prepolymer" refers to a compound formed by polymerizing monomers, and a compound that can form a polymer by further polymerization.

(Polymerizable composition (x-1)) The energy-ray polymerizable component contained in the polymerizable composition (x-1) is a component polymerized by irradiation of energy rays, and has an energy-ray polymerizable functional group. As the energy ray polymerizable functional group, for example, those having a carbon-carbon double bond such as (meth)acryloyl, vinyl, and allyl groups can be cited. Still, in this specification, such as (meth)acrylic acid group, allyl group, etc., a part of the vinyl group or functional group containing substituted vinyl group, and vinyl group or substituted vinyl group itself are collectively referred to as "vinyl group". Contains base". Hereinafter, each component contained in the polymerizable composition (x-1) will be described.

[Monomer with energy-ray polymerizable functional group (a1)] As the monomer (a1) having an energy ray polymerizable functional group, any monomer having an energy ray polymerizable functional group may have a hydrocarbon group or an energy ray polymerizable functional group in addition to the energy ray polymerizable functional group. Functional groups other than groups.

As the hydrocarbon group possessed by the component (a1), for example, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a combination of these, and the like can be cited. The aliphatic hydrocarbon group may be a linear or branched aliphatic hydrocarbon group, or an alicyclic hydrocarbon group. Examples of linear or branched aliphatic hydrocarbon groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, sec-butyl, and n-pentyl. Base, n-hexyl, 2-ethylhexyl, n-octyl, isooctyl, n-decyl, n-dodecyl, n-myristyl, n-palmityl, n-stearyl, etc. The aliphatic hydrocarbon group with 1-20 carbons. Examples of the alicyclic hydrocarbon group include alicyclic hydrocarbon groups having 3 to 20 carbon atoms such as cyclopentyl, cyclohexyl, and isobornyl. As an aromatic hydrocarbon group, a phenyl group can be mentioned, for example. Examples of the group combining an aliphatic hydrocarbon group and an aromatic hydrocarbon group include phenoxyethyl and benzyl. Among them, the component (a1) is preferably one containing an energy-ray polymerizable functional group and a linear or branched aliphatic hydrocarbon group from the viewpoint of further enhancing the adhesive force of the adhesive layer (X1) Monomer (a1-1) (hereinafter also referred to as "(a1-1) component"), monomer (a1-2) having energy ray polymerizable functional group and alicyclic hydrocarbon group (hereinafter also referred to as "(a1) -2) Ingredients") etc.

When the component (a1) contains the component (a1-1), the content is preferably 20 to 80% by mass, more preferably 40 to 70% by mass, and still more preferably, relative to the total (100% by mass) of the components (a1) It is 50-60% by mass. When the component (a1) contains the component (a1-2), the content is preferably 5-60% by mass, more preferably 10-40% by mass, and still more preferably, relative to the total (100% by mass) of the components (a1) It is 20-30% by mass.

As a monomer having an energy ray polymerizable functional group and a functional group other than the energy ray polymerizable functional group, as a functional group other than the energy ray polymerizable functional group, for example, having a hydroxyl group, a carboxyl group, a thiol group, 1 or Monomers such as secondary amino groups. Among them, the component (a1) preferably contains a monomer (a1-3) having an energy-ray polymerizable functional group and a hydroxyl group (hereinafter also referred to as “a1-3”) from the viewpoint of further improving the formability of the adhesive layer (X1) As "(a1-3) ingredients"). When the component (a1) contains the component (a1-3), its content is preferably from 1 to 60% by mass, more preferably from 5 to 30% by mass, and still more preferably with respect to the total (100% by mass) of the components (a1) It is 10-20% by mass.

(a1) The number of energy-beam polymerizable functional groups possessed by the component may be one or two or more. In addition, from the viewpoint of further enhancing the self-peelability of the adhesive layer (X1), the component (a1) preferably contains a monomer (a1-4) having 3 or more energy-ray polymerizable functional groups (hereinafter also referred to as As "(a1-4) ingredients"). When the component (a1) contains the component (a1-4), the content is preferably from 1 to 20% by mass, more preferably from 2 to 15% by mass, and still more preferably with respect to the total (100% by mass) of the components (a1) It is 3-10% by mass.

As a monomer having one energy-ray polymerizable functional group, a monomer having one vinyl group-containing group (hereinafter also referred to as "polymerizable vinyl monomer") is preferred. As a monomer having two or more energy ray polymerizable functional groups, a monomer having two or more (meth)acrylic groups is preferred (hereinafter also referred to as "multifunctional (meth)acrylate monomer") . When the component (a1) contains the above-mentioned compound, the cohesive force of the adhesive obtained by polymerization is increased, and the adhesive layer (X1) with less contamination by the adherend after peeling can be formed.

"Polymerizable vinyl monomer" As a polymerizable vinyl monomer, if it has a vinyl group-containing group, it will not specifically limit, Conventionally well-known thing can be used suitably. The polymerizable vinyl monomer may be used alone or in combination of two or more kinds.

Examples of polymerizable vinyl monomers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and pentyl (meth)acrylate ( Meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, dodecyl ( Compounds corresponding to the above-mentioned (a1-1) component such as meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, etc.; cyclohexyl (Meth)acrylate, isobornyl (meth)acrylate and other compounds corresponding to the above component (a1-2); phenoxyethyl (meth)acrylate, benzyl (meth)acrylate , Polyoxyalkylene-modified (meth)acrylate, etc., in the molecule does not have a functional group other than vinyl-containing group (meth)acrylate, etc. Among these, 2-ethylhexyl acrylate and isobornyl acrylate are preferred.

The polymerizable vinyl monomer further has a functional group other than the vinyl-containing group in the molecule. As this functional group, a hydroxyl group, a carboxyl group, a thiol group, a primary or secondary amino group, etc. are mentioned, for example. Among these, a polymerizable vinyl monomer having a hydroxyl group corresponding to the above-mentioned component (a1-3) is preferred. As a polymerizable vinyl monomer having a hydroxyl group, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, Hydroxyalkyl (meth)acrylate such as 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc.; N-hydroxy Hydroxyl-containing acrylamides such as methacrylamide and N-methylolmethacrylamide. In addition, examples of the polymerizable vinyl monomer having a carboxyl group include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. Among these, 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are preferable.

Also, as other polymerizable vinyl monomers, for example, vinyl esters such as vinyl acetate and vinyl propionate; olefins such as ethylene, propylene, and isobutylene; halogenated olefins such as chlorinated vinyl and vinylidene chloride Class; Styrenic monomers such as styrene and α-methylstyrene; Diene monomers such as butadiene, isoprene, and chloroprene; Nitriles such as acrylonitrile and methacrylonitrile Monomer; acrylamide, methacrylamide, N-methacrylamide, N-methylmethacrylamide, N,N-dimethyl (meth)acrylamide, N,N -Diethyl (meth)acrylamide, N-vinylpyrrolidone and other amide monomers; (meth)acrylic acid N,N-diethylaminoethyl, N-(meth)acrylic acid Monomorpholine and other monomers containing tertiary amine groups.

"Multifunctional (meth)acrylate monomer" As a polyfunctional (meth)acrylate monomer, if it is a monomer which has 2 or more (meth)acryl groups in one molecule, it will not specifically limit, Conventionally well-known thing can be used suitably. A polyfunctional (meth)acrylate monomer may be used individually by 1 type, and may use 2 or more types together.

Examples of polyfunctional (meth)acrylate monomers include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and neopentyl glycol di(meth)acrylate. (Meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, Dicyclopentyl (pentanyl) di(meth)acrylate, caprolactone modified dicyclopentenyl di(meth)acrylate, ethylene oxide modified phosphoric acid di(meth)acrylate, di(acrylic acid) 2-functional (meth)acrylate monomers such as oxyethyl) isocyanurate, allylated cyclohexyl di(meth)acrylate, and ethylene oxide modified diacrylate isocyanurate; three Hydroxymethyl propane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide modified three Methylolpropane tri(meth)acrylate, ginseng (acryloxyethyl) isocyanurate, bis(acryloxyethyl) hydroxyethyl isocyanurate, isocyanuric acid oxidation Ethylene modified triacrylate, ε-caprolactone modified ginseng (acryloxyethyl) isocyanurate, diglycerol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, propionic acid Modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, caprolactone modified dipentaerythritol hexa(meth)acrylate, etc. are polyfunctional equivalent to the above (a1-4) component (Meth)acrylate monomers, etc.

"(A1) Content of ingredients" In the polymerizable composition (x-1), the total content of polymerizable vinyl monomers is preferably 10 to 80 relative to the total amount (100% by mass) of the active ingredients of the polymerizable composition (x-1) % By mass, more preferably 30 to 75% by mass, still more preferably 50 to 70% by mass. The total content of the polyfunctional (meth)acrylate monomers in the polymerizable composition (x-1) is preferably relative to the total amount (100% by mass) of the active ingredients of the polymerizable composition (x-1) It is 0.5 to 15% by mass, more preferably 1 to 10% by mass, and still more preferably 2 to 5% by mass. The total content of the component (a1) in the polymerizable composition (x-1) is preferably 15 to 90% by mass relative to the total amount (100% by mass) of the active ingredients of the polymerizable composition (x-1) , More preferably 35 to 80% by mass, still more preferably 55 to 75% by mass.

[Prepolymer with energy-ray polymerizable functional group (a2)] As the prepolymer (a2) having an energy ray polymerizable functional group, a prepolymer having one energy ray polymerizable functional group, a prepolymer having two or more energy ray polymerizable functional groups, and the like can be mentioned. Among them, the component (a2) preferably contains a prepolymer having two or more energy-ray polymerizable functional groups from the viewpoint of forming an adhesive layer with excellent self-peelability and less contamination by the adherend after peeling. , More preferably contains a prepolymer having two energy ray polymerizable functional groups, still more preferably contains a prepolymer having two energy ray polymerizable functional groups and having the energy ray polymerizable functional groups at both ends .

As the component (a2), it is preferable to contain a prepolymer having two or more (meth)acrylic groups (hereinafter also referred to as "multifunctional (meth)acrylate prepolymer") as an energy ray polymerizable function base. When the component (a2) contains the above-mentioned compound, the cohesive force of the adhesive obtained by polymerization is increased, and an adhesive layer (X1) with excellent self-peelability and less contamination by the adherend after peeling can be formed.

"Multifunctional (meth)acrylate prepolymer" As a polyfunctional (meth)acrylate prepolymer, if it is a prepolymer which has 2 or more (meth)acryl groups in one molecule, it will not specifically limit, Conventionally well-known thing can be used suitably. A polyfunctional (meth)acrylate prepolymer may be used individually by 1 type, and may use 2 or more types together.

Examples of multifunctional (meth)acrylate prepolymers include urethane acrylate prepolymers, polyester acrylate prepolymers, epoxy acrylate prepolymers, and polyether acrylates. Prepolymers, polybutadiene acrylate prepolymers, polysiloxane acrylate prepolymers, polypropylene acrylate prepolymers, etc.

Urethane acrylate prepolymers, such as polyalkylene polyols, polyether polyols, polyester polyols, hydrogenated isoprene with hydroxyl end, and hydrogenated butadiene with hydroxyl end Such compounds, and the polyurethane prepolymer obtained by the reaction with polyisocyanate are obtained by esterification with (meth)acrylic acid or (meth)acrylic acid derivatives.

As the polyalkylene polyol used in the production of the urethane acrylate-based prepolymer, for example, polypropylene glycol, polyethylene glycol, polybutylene glycol, polyhexylene glycol, etc. can be cited. Among them, Preferably it is polypropylene glycol. Furthermore, when the number of functional groups of the resulting urethane acrylate prepolymer is set to 3 or more, for example, glycerin, trimethylolpropane, triethanolamine, pentaerythritol, ethylenediamine, diethylenetriamine, Sorbitol, sucrose, etc. are sufficient.

As the polyisocyanate used in the production of urethane acrylate prepolymers, for example, aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylene diisocyanate; phenylmethylene diisocyanate, diisocyanate, etc. Aromatic diisocyanates such as tolyl diisocyanate and diphenyl diisocyanate; alicyclic diisocyanates such as dicyclohexylmethane diisocyanate and isophorone diisocyanate. Among these, aliphatic diisocyanates are preferred. The isocyanate is more preferably hexamethylene diisocyanate. However, the polyisocyanate is not limited to bifunctional, and trifunctional or more can also be used.

Examples of (meth)acrylic acid derivatives used in the production of urethane acrylate prepolymers include 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, and other hydroxyalkyl (meth)acrylic acid derivatives. Group) acrylate; 2-isocyanate ethyl acrylate, 2-isocyanate ethyl methacrylate, 1,1-bis (acryloyloxymethyl) ethyl isocyanate, etc., among these, 2- Isocyanate ethyl acrylate.

As other methods for producing urethane acrylate prepolymers, polyalkylene polyols, polyether polyols, polyester polyols, hydrogenated isoprene with hydroxyl end, and hydroxyl end A method of reacting the hydroxyl group of the hydrogenated butadiene and other compounds with the -N=C=O part of the isocyanate alkyl (meth)acrylate. In this case, as the isocyanate alkyl (meth)acrylate, for example, the above-mentioned 2-isocyanate ethyl acrylate, 2-isocyanate ethyl methacrylate, 1,1-bis(acryloyloxymethyl) can be used. Group) ethyl isocyanate and the like.

The polyester acrylate-based prepolymer can be obtained, for example, by esterifying the hydroxyl groups of a polyester prepolymer having hydroxyl groups at both ends obtained by the condensation of a polycarboxylic acid and a polyol with (meth)acrylic acid . In addition, it can also be obtained by esterifying the terminal hydroxyl group of a prepolymer obtained by adding an alkylene oxide to a polycarboxylic acid with (meth)acrylic acid.

Epoxy acrylate-based prepolymers, for example, can be obtained by reacting (meth)acrylic acid due to the relatively low molecular weight bisphenol-type epoxy resin, novolak-type epoxy resin, and other oxirane (Oxirane) rings. Obtained by esterification. In addition, epoxy acrylate prepolymers of the carboxyl group-modified type in which the epoxy acrylate prepolymer is partially modified with dibasic carboxylic anhydride can also be used.

The polyether acrylate prepolymer can be obtained, for example, by esterifying the hydroxyl group of a polyether polyol with (meth)acrylic acid.

The polypropylene acrylate-based prepolymer may have an acryl group on the side chain, or may have an acryl group at both ends or one end. The polypropylene acrylate prepolymer having an acryl group in the side chain is obtained, for example, by adding glycidyl methacrylate to the carboxyl group of polyacrylic acid. In addition, the polypropylene acrylate prepolymer having acryl groups at both ends can be constructed by using, for example, a polyacrylate prepolymer synthesized by the ATRP (Atom Transfer Radical Polymerization) method. It is obtained by introducing acryloyl groups at both ends.

(a2) The mass average molecular weight (Mw) of the component is preferably 10,000 to 350,000, more preferably 15,000 to 200,000, and still more preferably 20,000 to 50,000.

"(A2) Content of ingredients" The total content of the polyfunctional (meth)acrylate prepolymer in the polymerizable composition (x-1) is higher than the total amount (100% by mass) of the active ingredients of the polymerizable composition (x-1) It is preferably 10 to 60% by mass, more preferably 15 to 55% by mass, and still more preferably 20 to 30% by mass. The total content of the component (a2) in the polymerizable composition (x-1) is preferably 10-60% by mass relative to the total amount (100% by mass) of the active ingredients of the polymerizable composition (x-1) , More preferably 15 to 55% by mass, still more preferably 20 to 30% by mass.

The content ratio of (a2) component and (a1) component in the polymerizable composition (x-1) [(a2)/(a1)] is preferably 10/90 to 70/30 on a mass basis, more preferably It is 20/80-50/50, more preferably 25/75-40/60.

Among the above-mentioned energy ray polymerizable components, it is preferable that the polymerizable composition (x-1) contains a polymerizable vinyl monomer, a polyfunctional (meth)acrylate monomer and a polyfunctional (meth)acrylate prepolymer Things. Polymerizable vinyl monomers, polyfunctional (meth)acrylate monomers, and polyfunctional (meth)acrylate prepolymers among the energy-ray polymerizable components contained in the polymerizable composition (x-1) The total content is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and still more preferably 99% by mass relative to the total amount (100% by mass) of the energy ray polymerizable components % Or more and may be 100% by mass.

The total content of the energy ray polymerizable components in the polymerizable composition (x-1) is preferably 70-98 mass relative to the total amount (100% by mass) of the active ingredients of the polymerizable composition (x-1) %, more preferably 75 to 97% by mass, still more preferably 80 to 96% by mass, still more preferably 82 to 95% by mass.

The polymerizable composition (x-1) of one aspect of the present invention may preferably contain thermally expandable particles in addition to the energy-ray polymerizable component. That is, it is preferable to irradiate the polymerizable composition (x-1) containing the energy-ray polymerizable component and heat-expandable particles with the adhesive layer (X1) to form the polymer of the energy-ray polymerizable component Steps of method formation.

[Thermally expandable particles] The heat-expandable particles may be particles that expand by heating. The expansion start temperature (t) of the heat-expandable particles can be appropriately adjusted within the above range according to the application of the adhesive sheet. For example, from the viewpoint of suppressing the expansion of the heat-expandable particles due to temperature rise when grinding the object to be ground, etc. In view of this, it is preferably 50°C or higher, more preferably 55°C or higher, still more preferably 60°C or higher, and still more preferably 70°C or higher, from the viewpoint of suppressing the thermal change of the adherend during heat peeling, It is preferably 110°C or lower, more preferably 105°C or lower, still more preferably 100°C or lower, and still more preferably 95°C or lower. In this specification, the expansion start temperature (t) of the thermally expandable particles means the value measured according to the following method. [Measuring method of expansion start temperature (t) of thermally expandable particles] An aluminum cup with a diameter of 6.0 mm (inner diameter of 5.65 mm) and a depth of 4.8 mm was made, 0.5 mg of thermally expandable particles as the measurement object was added, and a sample of aluminum cap (diameter 5.6 mm, thickness 0.1 mm) was attached to it. Use a dynamic viscoelasticity measuring device, and measure the height of the sample from the upper part of the aluminum cover with a force of 0.01N by the pressurizer. Furthermore, by heating the pressure bar with a force of 0.01N from 20°C to 300°C at a temperature increase rate of 10°C/min, the displacement amount of the pressure bar in the vertical direction is measured, and it is aligned with the positive direction. The starting temperature of displacement is defined as the starting temperature of expansion (t).

The thermally expandable particles are preferably microencapsulated foaming agents, which are composed of an outer shell made of a thermoplastic resin and an inner packaging component, which is enclosed in the outer shell and heated to a specified temperature gasification. The thermoplastic resin constituting the outer shell of the microencapsulated foaming agent is not particularly limited, and at the expansion start temperature (t) of the thermally expandable particles, a material and composition capable of causing state changes such as melting, dissolution, and cracking may be appropriately selected. Examples of the above-mentioned thermoplastic resins include vinylidene chloride-acrylonitrile copolymers, polyvinyl alcohol, polyvinyl butyral, polymethmethacrylate, polyacrylonitrile, polyvinylidene chloride, and polyvinylidene chloride. Wait. These thermoplastic resins may be used alone or in combination of two or more.

As the component encapsulated in the outer shell of the microencapsulated foaming agent, that is, the encapsulated component, if it expands at the expansion start temperature (t) of the thermally expandable particles, for example, propane, propylene, butene, n -Butane, isobutane, isopentane, neopentane, n-pentane, n-hexane, isohexane, n-heptane, n-octane, cyclopropane, cyclobutane, petroleum ether, etc. Low boiling point liquid. These internal components may be used alone or in combination of two or more. The expansion start temperature (t) of the thermally expandable particles can be adjusted by appropriately selecting the type of the inner component.

The average particle diameter of the heat-expandable particles at 23°C before thermal expansion is preferably 1-30 μm, more preferably 4-25 μm, still more preferably 6-20 μm, and still more preferably 10-15 μm. Furthermore, the average particle diameter (D ₅₀ ) of the thermally expandable particles is the volume median particle diameter (D ₅₀ ), which means that a laser diffraction particle size distribution measuring device (for example, manufactured by Malvern, product name "Master Sizer 3000") measured the particle distribution of thermally expandable particles before expansion. The cumulative volume frequency calculated from the smaller particle diameter corresponds to 50% of the particle diameter.

The 90% particle diameter (D ₉₀ ) of the thermally expandable particles at 23° C. before thermal expansion is preferably 2-60 μm, more preferably 8-50 μm, still more preferably 12-40 μm, and still more preferably 20-30 μm. Furthermore, the 90% particle diameter (D ₉₀ ) of thermally expandable particles means the particle distribution of thermally expandable particles before expansion as measured by the above-mentioned laser diffraction particle size distribution measuring device. The calculated particle diameter is smaller The cumulative volume frequency calculated by the author is equivalent to 90% of the particle diameter.

The maximum volume expansion rate when the heat-expandable particles are heated to a temperature higher than the expansion start temperature (t) is preferably 1.5 to 200 times, more preferably 2 to 150 times, still more preferably 2.5 to 120 times, and More preferably, it is 3 to 100 times.

The content of the thermally expandable particles is preferably 1-30% by mass relative to the total amount (100% by mass) of the active ingredient of the polymerizable composition (x-1) or the total mass (100% by mass) of the adhesive layer (X1) , More preferably 2-25% by mass, still more preferably 3-20% by mass. If the content of the thermally expandable particles is 1% by mass or more, there is a tendency to improve the peelability during heat peeling. In addition, if the content of the thermally expandable particles is 30% by mass or less, the adhesive strength of the adhesive layer (X1) becomes good, and curling of the adhesive sheet during heat peeling is suppressed, and the workability tends to be improved.

[Other ingredients] The polymerizable composition (x-1) may contain components other than energy-ray polymerizable components and thermally expandable particles. Examples of the above-mentioned other components include photopolymerization initiators, tackifiers, and tackifier additives used for general tackifiers other than the above-mentioned components. Among these, it is preferable that the polymerizable composition (x-1) contains a photopolymerization initiator.

"Photopolymerization initiator" When the polymerizable composition (x-1) contains a photopolymerization initiator, the energy-beam polymerizable component can be polymerized more efficiently.

Examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, and dimethylamine. Acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1- Phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-propane-1-one, 4- (2-Hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone Ketone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethyl Thioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal , P-dimethylaminobenzoate, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]acetone], 2,4,6-trimethyl Benzyl-diphenyl-phosphine oxide and the like. One type of photopolymerization initiator may be used alone, or two or more types may be used in combination.

When the polymerizable composition (x-1) contains a photopolymerization initiator, its content is preferably 0.1-10 parts by mass, more preferably 0.2-5 parts by mass, and still more with respect to 100 parts by mass of energy-ray polymerizable components. Preferably, it is 0.3 to 1 part by mass. If the content of the photopolymerization initiator is 0.1 parts by mass or more, the polymerization of the energy ray polymerizable component can be performed more efficiently. On the other hand, if the content is 10 parts by mass or less, it becomes possible to disappear or reduce the photopolymerization initiator remaining unreacted directly, and it becomes easy to adjust the resulting adhesive layer (X1) to desired physical properties.

"Adhesive Agent" Adhesion imparting agent is an ingredient that aims to increase the adhesion more, and is used if necessary. In this specification, the "adhesive imparting agent" refers to those having a mass average molecular weight (Mw) of less than 10,000, which is different from the adhesive resin described later. The mass average molecular weight (Mw) of the adhesion imparting agent is less than 10,000, preferably 400 to 9,000, more preferably 500 to 8,000, and still more preferably 800 to 5,000.

Examples of adhesion-imparting agents include rosin-based resins, terpene-based resins, styrene-based resins, pentene produced by the thermal decomposition of naphtha, isoprene, piperine, 1,3-pentadiene, etc. C5 petroleum resin obtained by copolymerizing C5 distillate, C9 petroleum resin obtained by copolymerizing C9 distillate, such as indene and vinyl toluene produced by thermal decomposition of naphtha, and hydrogenated resin such as hydrogenation.

The softening point of the adhesion imparting agent is preferably 60 to 170°C, more preferably 65 to 160°C, and still more preferably 70 to 150°C. In this specification, the "softening point" of the adhesion imparting agent means a value measured in accordance with JIS K 2531. One type of adhesion imparting agent may be used alone, or two or more types with different softening points and structures may be used in combination. When two or more types of adhesion-imparting agents are used, it is preferable that the weighted average of the softening points of the plurality of adhesion-imparting agents falls within the above-mentioned range.

When the polymerizable composition (x-1) contains an adhesion-imparting agent, its content relative to the total amount (100% by mass) of the active ingredients of the polymerizable composition (x-1) is preferably 0.01 to 65% by mass, more preferably It is 0.1 to 50% by mass, still more preferably 1 to 40% by mass, and still more preferably 2 to 30% by mass.

"Additives for Adhesives" Examples of additives for adhesives include silane coupling agents, antioxidants, softeners (plasticizers), rust inhibitors, pigments, dyes, retarders, reaction accelerators (catalysts), and ultraviolet absorbers. These adhesive additives may be used alone, or two or more of them may be used in combination.

When the polymerizable composition (x-1) contains adhesive additives, the content of the individual adhesive additives is preferably 0.0001-20 parts by weight, more preferably 0.001-10 parts by weight relative to 100 parts by weight of the energy ray polymerizable component Mass parts.

In addition, the polymerizable composition (x-1) may contain a solvent such as a diluent within a range that does not violate the purpose of the present invention, but preferably does not contain a solvent. That is, the polymerizable composition (x-1) is preferably a solvent-free polymerizable composition. Since the polymerizable composition (x-1) is a solvent-free polymerizable composition, when the adhesive layer (X1) is formed, the heating and drying of the solvent can be omitted, so that the thermally expandable particles during the heating and drying can be suppressed Swell. In addition, when a solvent is used, the heat-expandable particles are concentrated on one surface side as the volume decreases during drying, and the adhesion to the base material (Y) or the adhesion to the adhesive surface may be reduced. On the other hand, since the solvent-free polymerizable composition is contained in the energy ray polymerizable component and directly polymerizes in a state where the thermally expandable particles are uniformly dispersed to form the adhesive layer (X1), it is difficult to cause the above-mentioned problems. When the polymerizable composition (x-1) contains a solvent, the smaller the content, the better. The total amount (100% by mass) of the active ingredients of the polymerizable composition (x-1) is preferably 10% by mass or less, It is more preferably 1% by mass or less, still more preferably 0.1% by mass or less, and still more preferably 0.01% by mass or less.

The polymerizable composition (x-1) can be produced by mixing energy-ray polymerizable components, thermally expandable particles, and other components contained if necessary. Since the obtained polymerizable composition (x-1) is high molecular weight by the subsequent energy ray polymerization, when the layer is formed, the low molecular weight energy ray polymerizable component can be adjusted to an appropriate viscosity. Therefore, it is not necessary to add a solvent such as a diluent to the polymerizable composition, but it can be used as a coating solution directly for the formation of the adhesive layer (X1). Moreover, in the adhesive layer (X1) formed by irradiating the polymerizable composition (x-1) with energy rays, although it contains a variety of polymers that polymerize the energy ray polymerizable components, and dispersed in the polymer However, it is impossible or almost impractical to directly specify these thermally expandable particles in terms of structure and physical properties.

(Adhesive force of adhesive layer (X1) at 23℃ before thermal expansion) The adhesive force of the adhesive layer (X1) at 23°C before thermal expansion is preferably 0.1～12.0N/25mm, more preferably 0.5～9.0N/25mm, still more preferably 1.0～8.0N/25mm, and more Preferably it is 1.2～7.5N/25mm. If the adhesive force of the adhesive layer (X1) at 23°C before thermal expansion is 0.1N/25mm or more, it can be more effective to suppress unintentional peeling and position shift of the object during temporary fixation Wait. On the other hand, if the adhesive force is 12.0N/25mm or less, the peelability during heat peeling can be further improved. In this specification, the adhesive force of the adhesive layer means the adhesive force to the mirror surface of the silicon mirror wafer. In addition, in this specification, the adhesive force of the adhesive layer (X1) at 23°C before thermal expansion specifically means the value measured by the method described in the examples.

(Adhesive strength at 23℃ after thermal expansion of adhesive layer (X1)) The adhesive strength of the adhesive layer (X1) at 23°C after thermal expansion is preferably 1.5N/25mm or less, more preferably 0.05N/25mm or less, still more preferably 0.01N/25mm or less, and still more preferably 0N /25mm. Still, the so-called adhesive force is 0N/25mm, and the method of measuring the adhesive force at 23°C after thermal expansion described later refers to the measurement of the adhesive force below the limit. For the purpose of measurement, when fixing the adhesive sheet, it also includes that the adhesive force is too small and unintentionally In the case of peeling. In this specification, the adhesive force at 23°C after thermal expansion of the adhesive layer (X1) specifically means the value measured by the method described in the examples.

(Shear storage elastic modulus G'(23) of the adhesive layer (X1) at 23°C) Shear storage elastic modulus G'(23) of the adhesive layer (X1) at 23°C, preferably 1.0×10 ⁴ ~5.0×10 ⁷ Pa, more preferably 5.0×10 ⁴ to 1.0×10 ⁷ Pa, still more preferably 1.0×10 ⁵ to 5.0×10 ⁶ Pa. If the shear storage elastic modulus G'(23) of the adhesive layer (X1) is 1.0×10 ⁴ Pa or more, the positional deviation of the object during temporary fixation can be suppressed, and the adhesive layer ( X1) excessive sinking, etc. On the other hand, if the shear storage elastic modulus G'(23) is 5.0×10 ⁷ Pa or less, due to the expansion of the thermally expandable particles, unevenness is easily formed on the surface of the adhesive layer (X1), which improves heat peeling The tendency of time to peel off. In this specification, the shear storage elastic modulus G'(23) of the adhesive layer (X1) at 23°C means the value measured by the method described in the examples.

The adhesive layer (X1) is a layer containing heat-expandable particles, and the shear storage elastic modulus G'of the adhesive layer (X1) can be affected by the heat-expandable particles. From the standpoint of measuring the shear storage elastic modulus G'that excludes the influence of thermally expandable particles, it is possible to prepare an adhesive layer having the same composition as the adhesive layer (X1) (hereinafter also referred to as Is the "non-expandable adhesive layer (X1')") to measure the shear storage elastic modulus G'of the adhesive layer.

(Shear storage elastic modulus of non-expandable adhesive layer (X1') at 23°C G'(23)) Non-expandable adhesive layer (X1') storage elastic modulus of shear at 23°C G'(23) , Preferably 1.0×10 ⁴ to 5.0×10 ⁷ Pa, more preferably 5.0×10 ⁴ to 1.0×10 ⁷ Pa, still more preferably 1.0×10 ⁵ to 5.0×10 ⁶ Pa. If the shear storage elastic modulus G'(23) of the non-expandable adhesive layer (X1') is 1.0×10 ⁴ Pa or more, it can suppress the positional deviation and adhesion to the object during temporary fixation Excessive sinking of the agent layer (X1), etc. On the other hand, if the shear storage elastic modulus G'(23) is 5.0×10 ⁷ Pa or less, due to the expansion of the thermally expandable particles, unevenness is easily formed on the surface of the adhesive layer (X1), which improves heat peeling The tendency of time to peel off.

(The shear storage elastic modulus G'(t) of the non-expandable adhesive layer (X1') at the expansion start temperature (t)) The non-expandable adhesive layer (X1') at the beginning of the expansion of the aforementioned thermally expandable particles Shear storage elastic modulus G'(t) at temperature (t) is preferably 5.0×10 ³ ～1.0×10 ⁷ Pa, more preferably 1.0×10 ⁴ ～5.0×10 ⁶ Pa, still more preferably 5.0× 10 ⁴ ～1.0×10 ⁶ Pa. If the shear storage elastic modulus G'(t) of the non-expandable adhesive layer (X1') is 5.0×10 ³ Pa or more, it can suppress the positional deviation and adhesion to the object during temporary fixation. Excessive sinking of the agent layer (X1), etc., while suppressing curling of the adhesive sheet during heat peeling, tends to improve workability. On the other hand, if the shear storage elastic modulus G'(t) is 1.0×10 ⁷ Pa or less, due to the expansion of the thermally expandable particles, unevenness is easily formed on the surface of the adhesive layer (X1), which improves heat peeling The tendency of time to peel off. In this specification, the shear storage elastic modulus G'of the non-expandable adhesive layer (X1') at a specified temperature means the value measured by the method described in the examples.

(The thickness of the adhesive layer (X1) at 23°C) The thickness of the adhesive layer (X1) at 23°C is preferably 5 to 150 μm, more preferably 10 to 100 μm, and still more preferably 20 to 80 μm. If the thickness of the adhesive layer (X1) at 23°C is 5μm or more, it becomes easy to obtain sufficient adhesive force, which can prevent unintentional peeling from the object during temporary fixation, position shift of the object, etc. tendency. On the other hand, if the thickness of the adhesive layer (X1) at 23° C. is 150 μm or less, the peelability during heat peeling is improved, and curling of the adhesive sheet during heat peeling is suppressed, which tends to improve handleability. In this specification, the thickness of the adhesive layer means the value measured by the method described in the examples. In addition, the thickness of the adhesive layer (X1) is the value before the expansion of the thermally expandable particles.

＜Adhesive layer (X2)＞ The adhesive layer (X2) is a layer arbitrarily provided on the other surface side of the base material (Y). The adhesive layer (X2) may be a thermally expandable layer or a non-thermally expandable layer, but it is preferably a non-thermally expandable layer. In the adhesive layer (X1) and the adhesive layer (X2), by making the mechanism for reducing the adhesive force of the adhesive layer different, when performing treatment to reduce the adhesive force of either the adhesive layer, Suppress the unintentional decrease in the adhesive force of the adhesive layer of the other.

When the adhesive layer (X2) is a non-thermally expandable layer, the volume change rate (%) of the adhesive layer (X2) calculated from the above formula is less than 5%, preferably less than 2%, and more preferably less than 1%, more preferably less than 0.1%, and still more preferably less than 0.01%. Although the adhesive layer (X2) preferably does not contain thermally expandable particles, it may contain thermally expandable particles within a range that does not violate the purpose of the present invention. When the adhesive layer (X2) contains thermally expandable particles, the smaller the content, the better. Relative to the total mass (100% by mass) of the adhesive layer (X2), it is preferably less than 3% by mass, more preferably less than 1% by mass, still more preferably less than 0.1% by mass, still more preferably less than 0.01% by mass, and still more preferably less than 0.001% by mass.

The adhesive layer (X2) is preferably formed of an adhesive composition (x-2) containing an adhesive resin. Hereinafter, each component contained in the adhesive composition (x-2) will be described.

(Adhesive composition (x-2)) Adhesive composition (x-2) contains adhesive resin, if necessary, it may also contain crosslinking agent, adhesive imparting agent, polymerizable compound, polymerization initiator, and general adhesives other than the above components. Additives for adhesives, etc.

[Adhesive Resin] As the adhesive resin, it is sufficient if the resin alone has adhesiveness and has a mass average molecular weight (Mw) of 10,000 or more. The mass average molecular weight (Mw) of the adhesive resin, from the viewpoint of further enhancing the adhesive force of the adhesive layer (X2), is preferably 10,000 to 2 million, more preferably 20,000 to 1.5 million, and still more preferably 3 Ten thousand to one million.

Examples of adhesive resins include acrylic resins, urethane resins, polyisobutylene resins, and other rubber resins, polyester resins, olefin resins, silicone resins, and polyvinyl ether resins. Resin etc. These adhesive resins can be used singly or in combination of two or more. In addition, when these adhesive resins are copolymers having two or more structural units, the form of the copolymer may be any of block copolymers, random copolymers, and graft copolymers.

The adhesive composition (x-2) containing an adhesive resin is preferably cured by irradiation of energy rays from the viewpoint of different mechanisms for reducing the adhesive force of the adhesive layer (X1) The adhesive composition is more preferably a resin having an energy ray polymerizable functional group in the side chain of the above-mentioned adhesive resin. By being formed from the adhesive composition, the adhesive layer (X2) can be cured by energy ray irradiation to become an adhesive layer with reduced adhesive force. As the energy ray polymerizable functional group, for example, those having a carbon-carbon double bond such as (meth)acryloyl, vinyl, and allyl groups can be cited. As the energy beam, among the above, ultraviolet rays which are easy to handle are preferred. In addition, the adhesive composition (x-2) may be combined with an adhesive resin having an energy ray polymerizable functional group, or may replace an adhesive resin having an energy ray polymerizable functional group, and may contain a monomer having an energy ray polymerizable functional group. Body or prepolymer. Examples of the monomer or prepolymer having an energy-ray polymerizable functional group include the same energy-ray polymerizable components contained in the above-mentioned polymerizable composition (x-1).

When the adhesive composition (x-2) is an adhesive composition hardened by irradiation with energy rays, it is preferable that the adhesive composition further contains a photopolymerization initiator. By containing the photopolymerization initiator, the polymerization of the energy ray polymerizable component can be performed more efficiently. As the photopolymerization initiator, the same ones as the photopolymerization initiator which may contain the polymerizable composition (x-1) can be mentioned. The content of the photopolymerization initiator is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass relative to 100 parts by mass of the total amount of the adhesive resin, monomer and prepolymer having energy-ray polymerizable functional groups Parts, more preferably 0.05-2 parts by mass.

The adhesive resin preferably contains an acrylic resin from the viewpoint of expressing excellent adhesive force. The content of the acrylic resin in the adhesive composition (x-2) is preferably 30-100 mass relative to the total amount (100% by mass) of the adhesive resin contained in the adhesive composition (x-2) %, more preferably 50-100% by mass, still more preferably 70-100% by mass, and still more preferably 85-100% by mass.

The content of the adhesive resin in the adhesive composition (x-2) is preferably 35-100% by mass relative to the total amount (100% by mass) of the active ingredients of the adhesive composition (x-2), and more It is preferably from 50 to 100% by mass, still more preferably from 60 to 98% by mass, and still more preferably from 70 to 95% by mass.

[Crosslinking agent] In one aspect of the present invention, when the adhesive composition (x-2) contains an adhesive resin having a functional group, it is preferable that the adhesive composition (x-2) further contains a crosslinking agent. The crosslinking agent reacts with an adhesive resin having a functional group, and the functional group is used as a crosslinking starting point to crosslink the adhesive resins.

As a crosslinking agent, an isocyanate type crosslinking agent, an epoxy type crosslinking agent, an aziridine type crosslinking agent, a metal chelating agent type crosslinking agent, etc. are mentioned, for example. A crosslinking agent may be used individually by 1 type, and may use 2 or more types together. Among these crosslinking agents, an isocyanate-based crosslinking agent is preferred from the viewpoints of improving cohesive force and improving adhesive strength and the viewpoints of easy acquisition.

Although the content of the crosslinking agent is appropriately adjusted by the number of functional groups possessed by the adhesive resin, it is preferably 0.01-10 parts by mass, and more preferably 0.03 with respect to 100 parts by mass of the adhesive resin having functional groups. ~7 parts by mass, more preferably 0.05-5 parts by mass.

[Adhesion imparting agent] In one aspect of the present invention, the adhesive composition (x-2) may further contain an adhesive imparting agent from the viewpoint of further enhancing the adhesive force. As the adhesive imparting agent that can contain the adhesive composition (x-2), one equivalent to the adhesive imparting agent that can contain the polymerizable composition (x-1) can be used.

[Additives for Adhesives] As the additive for adhesives, the same ones as the additive for adhesives that can contain the polymerizable composition (x-1) can be mentioned. However, when the adhesive composition (x-2) does not contain heat-expandable particles, it is not necessary to avoid heating and drying above the expansion start temperature (t) of the heat-expandable particles, so the adhesive composition (x-2) is It may contain a solvent if necessary.

The adhesive composition (x-2) can be manufactured by mixing an adhesive resin, a crosslinking agent, an adhesive imparting agent, an adhesive additive, etc. if necessary.

[Adhesive strength of the adhesive layer (X2)] The adhesive force of the adhesive layer (X2) on the adhesive surface is preferably 0.1～10.0N/25mm, more preferably 0.2～8.0N/25mm, still more preferably 0.4～6.0N/25mm, and still more preferably 0.5 ～4.0N/25mm. If the adhesive force of the adhesive layer (X2) on the adhesive surface is 0.1N/25mm or more, it can more effectively suppress unintentional peeling and position shift of the adhered object during temporary fixation. On the other hand, if the adhesive force is 10.0N/25mm or less, no damage or the like is given to the adherend, and peeling becomes easy.

[Shear storage elastic modulus G'(23) of the adhesive layer (X2) at 23°C] Shear storage elastic modulus G'(23) of the adhesive layer (X2) at 23°C, preferably 5.0×10 ³ ~1.0×10 ⁷ Pa, more preferably 1.0×10 ⁴ to 5.0×10 ⁶ Pa, still more preferably 5.0×10 ⁴ to 1.0×10 ⁶ Pa. If the shear storage elastic modulus G'(23) of the adhesive layer (X2) is 5.0×10 ³ Pa or more, there is an adhesive layer that can suppress the positional deviation of the adhered body during temporary fixation. (X2) The tendency of excessive sinking. On the other hand, if the shear storage elastic modulus G'(23) is 1.0×10 ⁷ Pa or less, there is a tendency for the adhesion to the object to be improved. In this specification, the shear storage elastic modulus G'(23) of the adhesive layer (X2) at 23°C can be obtained by the same method as the shear storage elastic modulus G'of the adhesive layer (X1) at 23°C Determination.

[The thickness of the adhesive layer (X2) at 23°C] The thickness of the adhesive layer (X2) at 23°C is preferably 5 to 150 μm, more preferably 8 to 100 μm, still more preferably 12 to 70 μm, and still more preferably 15 to 50 μm. If the thickness of the adhesive layer (X2) at 23°C is 5μm or more, it becomes easy to obtain sufficient adhesive force, and it is possible to suppress unintentional peeling from the object during temporary fixation, position shift of the object, etc. tendency. On the other hand, if the thickness of the adhesive layer (X2) at 23°C is 150 μm or less, the handling of the adhesive sheet tends to become easy.

＜Peeling material＞ As the release material, a release sheet subjected to a double-sided release treatment, a release sheet subjected to a single-side release treatment, etc., and a substrate for the release material is coated with a release agent. As the base material for the release material, for example, plastic film, paper, etc. can be cited. Examples of plastic films include polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin; polypropylene resin, polyethylene resin, etc. The olefin resin film, etc., as papers, for example, high-quality paper, transparent paper, kraft paper, etc. can be cited.

Examples of release agents include rubber elastomers such as silicone resins, olefin resins, isoprene resins, and butadiene resins; long-chain alkyl resins, alkyd resins, and fluorine resins. Resin etc. A release agent may be used individually by 1 type, and may use 2 or more types together.

The thickness of the release material is preferably 10 to 200 μm, more preferably 20 to 150 μm, and still more preferably 35 to 80 μm.

[Method of manufacturing adhesive sheet] The method of manufacturing an adhesive sheet according to one aspect of the present invention is a method of manufacturing an adhesive sheet, which is a method of forming an adhesive layer (X1), including polymerizing the energy-ray polymerizable component and the thermally expandable particles. The step of irradiating the composition (x-1) with energy rays to form a polymer of the aforementioned energy-ray polymerizable component. The method of forming the adhesive layer (X1) preferably includes the following steps I and II. Step I: A step of forming a polymerizable composition layer including the polymerizable composition (x-1) on the surface side of one side of the substrate (Y) Step II: A step of forming a polymer of the energy-ray polymerizable component by irradiating the polymerizable composition layer with energy rays, and forming an adhesive layer (X1) containing the polymer and the thermally expandable particles

<Step I> If step I is a step of forming a polymerizable composition layer on one surface side of the substrate (Y), although it is not particularly limited, it preferably includes the following steps I-1 to I-3. Step I-1: The step of coating the polymerizable composition (x-1) on the peeling treatment surface of the release material to form a polymerizable composition layer Step I-2: A step of irradiating the polymerizable composition layer with the first energy ray to prepare the energy ray polymerizable component in the polymerizable composition layer Step I-3: Step of attaching the substrate (Y) to the polymerizable composition layer after the first energy ray irradiation

(Step I-1) Step I-1 is a step of coating the polymerizable composition (x-1) on the release-treated surface of the release material to form a polymerizable composition layer. As a method of applying the polymerizable composition (x-1) to the release material in step I-1, for example, spin coating, spray coating, bar coating, knife coating, roll coating, and knife coating Method, die coating method, gravure coating method, etc.

The polymerizable composition (x-1) is as described above, and is preferably a solvent-free polymerizable composition. When the polymerizable composition (x-1) is a solvent-free polymerizable composition, the heating and drying step of the solvent may not be performed in this step. On the other hand, when the polymerizable composition (x-1) contains a solvent in a range that does not violate the purpose of the present invention, after coating the polymerizable composition (x-1), it can be heated and dried, but heating in this case The temperature becomes less than the expansion start temperature (t) of the thermally expandable particles.

(Step I-2) Step I-2 is a step of irradiating the polymerizable composition layer formed in step I-1 with the first energy ray to prepare the energy ray polymerizable component in the polymerizable composition layer. The first energy ray irradiation is performed for the purpose of increasing the viscosity of the polymerizable composition by preparing polymerizable energy ray polymerizable components to improve the shape maintenance of the polymerizable composition layer. In the first energy ray irradiation, the energy ray polymerizable components are not completely polymerized, and remain in the preliminary polymerization. Thereby, the adhesion between the polymerizable composition layer and the substrate (Y) in step I-3 can be improved.

As the energy ray used for the first energy ray irradiation in step I-2, among the above, ultraviolet rays that are easy to handle are preferred. UV irradiation of the first energy ray illuminance is preferably 70 ~ 250mW / cm ^2, more preferably 100 ~ 200mW / cm ^2, and still more preferably 130 ~ 170mW / cm ^2. In addition, the amount of ultraviolet light irradiated on the first energy line is preferably 40 to 200 mJ/cm ² , more preferably 60 to 150 mJ/cm ² , and still more preferably 80 to 120 mJ/cm ² . The first energy ray irradiation can be performed once or divided into multiple times. In addition, in order to suppress the temperature rise of the polymerizable composition layer due to the heat of polymerization or the like, it may be performed while cooling the polymerizable composition layer.

(Step I-3) Step I-3 is a step of attaching the polymerizable composition layer to the substrate (Y) after the first energy ray irradiation. The method of attaching the base material (Y) to the polymerizable composition layer is not particularly limited. For example, a method of laminating the base material (Y) on the exposed surface of the polymerizable composition layer can be mentioned. The lamination may be performed while heating or without heating, but from the viewpoint of suppressing the expansion of thermally expandable particles, it is preferably performed without heating. At this time, the polymerizable composition layer prepared for polymerization is irradiated with the first energy ray and has good adhesion to the substrate (Y) even if it is not heated.

<Step II> Step II is a step of irradiating the polymerizable composition layer formed in Step I with energy rays to form a polymer of energy-ray polymerizable components, and forming an adhesive layer (X1) containing the polymer and thermally expandable particles.

Here, when the first energy ray irradiation is performed in step I, the energy ray irradiation in step II becomes the second energy ray irradiation performed on the polymerizable composition layer after preliminary polymerization. The energy ray irradiation in step II is preferably different from the first energy ray irradiation, and furthermore, even if the energy ray is irradiated, the energy ray polymerizable component can not be polymerized substantially. By the energy ray irradiation of step II, polymerization of the energy ray polymerizable component is performed to form a polymer of the energy ray polymerizable component constituting the adhesive layer (X1).

As the energy ray used for the energy ray irradiation in step II, among the above, ultraviolet rays that are easy to handle are preferred. The illuminance of the ultraviolet rays irradiated by the energy rays in step II is preferably 100-350 mW/cm ² , more preferably 150-300 mW/cm ² , and still more preferably 180-250 mW/cm ² . The quantity of ultraviolet light irradiating step II of the energy ray, preferably 500 ~ 4,000mJ / cm ^2, more preferably 1,000 ~ 3,000mJ / cm ^2, and still more preferably 1,500 ~ 2,500mJ / cm ^2. The energy ray irradiation in step II can be performed once or divided into multiple times. In addition, in order to suppress the temperature rise of the polymerizable composition layer due to the heat of polymerization or the like, it may be performed while cooling the polymerizable composition layer.

Furthermore, when step I includes the above steps I-1 to I-3, the polymerizable composition layer is obtained as an intermediate layer of a laminate laminated in this order of the release material, the polymerizable composition layer, and the substrate (Y). At this time, the second energy ray irradiation can be performed on the laminate having this configuration. In this case, from the viewpoint that it is possible to irradiate sufficient energy rays to the polymerizable composition layer existing as the intermediate layer of the laminate, it is preferable that one or more selected from the release material and the base material (Y) are Those with energy line penetration.

In any of the steps included in the above-mentioned steps I and II, from the viewpoint of suppressing the expansion of the thermally expandable particles, it is preferable that the step not including the step of heating the polymerizable composition is not included. Here, the term "heating" here means, for example, deliberate heating during drying, lamination, etc., and does not include the heat imparted to the polymerizable composition by energy ray irradiation, and the polymerizability by energy ray The temperature rise caused by the polymerization heat generated by the polymerization of the composition. If it is necessary to include the step of heating the polymerizable composition, the heating temperature is preferably "a temperature lower than the expansion initiation temperature (t)", and more preferably the "expansion initiation temperature (t)-5°C" Hereinafter, it is more preferably "expansion initiation temperature (t)-10°C" or less, and still more preferably "expansion initiation temperature (t)-15°C" or less. Moreover, when the temperature of the polymerizable composition increases unintentionally, it is preferable that the temperature of the polymerizable composition be cooled so as to fall within the above-mentioned temperature range.

When the adhesive sheet of one aspect of the present invention has the structure of the two-sided adhesive sheet, the manufacturing method of the adhesive sheet of one aspect of the present invention preferably further includes the following step III.

<Step III> Step III: Step of forming an adhesive layer (X2) on the other side of the substrate (Y)

The method of forming the adhesive layer (X2) may be appropriately determined according to the type of composition constituting the adhesive layer (X2). For example, when the adhesive composition (x-2) is used to form the adhesive layer (X2), step III preferably includes the following steps III-1 and III-2. Step III-1: Coating the adhesive composition (x-2) on one side of the release material to form the adhesive layer (X2) Step III-2: A step of attaching the adhesive layer (X2) formed in Step III-1 to the other side of the substrate (Y)

As the method of applying the adhesive composition (x-2) in step III-1, the same methods as those listed as the method of applying the polymerizable composition (x-1) in step I-1 can be cited method. Furthermore, when the adhesive layer (X2) contains a solvent, it may include a step of drying the coating film after applying the adhesive composition (x-2). Still, as described above, the peeling material used in step III-1 and the peeling material used in step I-1 are preferably used from the viewpoint of suppressing peeling of the adhesive layer due to the separation of the two peeling materials Become a designer with a different way of peeling force.

As the method of attaching the adhesive layer (X2) to the substrate (Y) in step III-2, the same method as the method of attaching the substrate (Y) to the polymerizable composition layer in step I-3 can be cited The method is preferably the same.

[Purpose and method of use of adhesive sheet] Although the adhesive sheet of one aspect of the present invention has sufficient adhesive force when temporarily fixed, it can also be heated and peeled at a low temperature and can be applied to various applications. Specifically, for example, suitable for dicing wafers used when cutting semiconductor wafers and other implants, back grinding wafers used in the step of grinding the implants, semiconductor wafers singulated by dicing, etc. Expansion tape used to expand the distance between the objects to be adhered, transfer tape used for reversing the front and back of the object to be adhered, such as semiconductor chips, and temporary fixation used for temporary fixation of inspection objects Use thin slices and so on.

The body of the adhesive sheet of one aspect of the present invention is not particularly limited, but examples include semiconductor wafers, semiconductor wafers, compound semiconductors, semiconductor packages, electronic parts, sapphire substrates, displays, and panel substrates. . Since the adhesive sheet of one aspect of the present invention can be peeled off by heating at a low temperature, it is suitable for temporarily fixing a heat-sensitive substrate such as a semiconductor chip with DAF attached.

The heating temperature when the adhesive sheet of one aspect of the present invention is heated and peeled from the adherend is higher than the expansion start temperature (t) of the heat-expandable particles, preferably higher than the expansion start temperature (t) "The temperature" is more preferably "expansion initiation temperature (t) + 2°C" or more, still more preferably "expansion initiation temperature (t) + 4°C" or more, and still more preferably "expansion initiation temperature ( t)+5℃" or more. In addition, from the viewpoint of energy saving and suppression of the thermal change of the object during heat peeling, it is preferably "expansion initiation temperature (t) + 50°C" or less, and more preferably "expansion initiation temperature ( t)+40°C” or less, and more preferably “expansion initiation temperature (t)+20°C” or less. In addition, the heating temperature at the time of heating and peeling, from the viewpoint of suppressing the thermal change of the adherend, is within the range of the expansion initiation temperature (t) or higher, preferably 120°C or lower, more preferably 115°C or lower, and still more It is preferably 110°C or lower, and still more preferably 105°C or lower.

The heating method is not particularly limited as long as it can be heated to a temperature higher than the temperature at which the thermally expandable particles expand. For example, electric heaters; dielectric heating; magnetic heating; near infrared, mid-infrared, far infrared, etc. The infrared rays are heated by electromagnetic waves. Furthermore, the heating method can be any of contact heating methods such as heating rollers and heating stamping, and non-contact heating methods such as environmental heating devices and infrared radiation.

[Method of Manufacturing Semiconductor Device] The present invention also provides a method for manufacturing a semiconductor device using the adhesive sheet of one aspect of the present invention. As an aspect of the manufacturing method of the semiconductor device of the present invention, an aspect in which the adhesive sheet of one aspect of the present invention is used as a temporary fixing sheet for processing an object to be attached (hereinafter also referred to as "first The manufacturing method of the state-of-the-art semiconductor device").

<The manufacturing method of the semiconductor device of the first aspect> As a more specific aspect of the method of manufacturing a semiconductor device of the first aspect, a method of manufacturing a semiconductor device can be cited, which is included in the adhesive sheet of one aspect of the present invention to attach a work object to the processing object The material is subjected to one or more treatments selected from grinding treatment and singulation treatment (hereinafter also referred to as "processing treatment"). After this treatment, the adhesive sheet is heated to the expansion starting temperature (t) or higher , Below 120℃, the step of expanding the adhesive layer (X1). In this specification, the term "semiconductor device" refers to a device that can perform functions by utilizing semiconductor characteristics. Examples include wafers with integrated circuits, thinned wafers with integrated circuits, chips with integrated circuits, thinned chips with integrated circuits, electronic parts including these chips, and electronic components with Parts of electronic equipment, etc.

In the method of manufacturing a semiconductor device of the first aspect, the adhesive layer of the adhesive sheet for attaching the object to be processed may be the adhesive layer (X1), and when the adhesive sheet is a double-sided adhesive sheet, it may be the adhesive layer (X2). When the adhesive sheet is a double-sided adhesive sheet, it is preferable to attach the additional object to the adhesive layer on one side and attach the support to the adhesive layer on the other side. The object to be processed is fixed to the support through the adhesive sheet. During processing, the vibration, position shift, and damage of the fragile object can be suppressed, and the processing accuracy and processing speed can be improved. At this time, the support may be attached to the adhesive layer (X1) and the object to be processed may be attached to the adhesive layer (X2), or the object may be attached to the adhesive layer (X1 ), the support is attached to the adhesive layer (X2). When the support is attached to the adhesive layer (X1) and the object to be processed is attached to the adhesive layer (X2), the support is attached to an adhesive with excellent peelability after heat treatment For the layer (X1), even if the support is made of a hard material, it can be peeled off by heating without bending the adhesive sheet and the support. In addition, the adhesive layer (X2) may be appropriately composed according to the type of object to be processed. For example, when the adhesive layer (X2) is irradiated with energy rays to become an adhesive layer that reduces the adhesive force, the source Residues of self-heating expandable particles can be peeled off without contaminating the object to be processed. On the other hand, when the object to be processed is attached to the adhesive layer (X1) and the support is attached to the adhesive layer (X2), the object is attached to the heat treatment and peeled off The adhesive layer (X1) with excellent properties can peel the object from the adhesive sheet by self-peeling when it is heated and peeled after processing, so the damage to the object can be reduced.

As the adhesive sheet of one aspect of the present invention, when a double-sided adhesive sheet is used, the manufacturing method of the semiconductor device of the first aspect is preferably a manufacturing method including the following steps 1A to 5A (hereinafter also referred to as "manufacturing method A" ). Step 1A: A step of attaching an additional object to the adhesive layer (X2) of the adhesive sheet, and attaching a support to the adhesive layer (X1) Step 2A: A step of performing one or more processing selected from grinding processing and singulation processing on the aforementioned processing object Step 3A: A step of attaching a thermosetting film on the side opposite to the adhesive layer (X2) of the object to be processed. Step 4A: The step of heating the adhesive sheet to a temperature above the expansion initiation temperature (t) and below 120°C to separate the adhesive layer (X1) from the support Step 5A: Step of separating the adhesive layer (X2) from the object to be processed

Hereinafter, the method of manufacturing a semiconductor device including steps 1A to 5A will be described with reference to the drawings. In the following description, although an example in the case of using a semiconductor wafer as an object to be processed will be mainly described, the same applies to other objects to be processed.

(Step 1A) Step 1A is a step of attaching the additional object to the adhesive layer (X2) of the adhesive sheet, and attaching the support to the adhesive layer (X1). 3 is a cross-sectional view illustrating the steps of attaching the adhesive layer (X2) of the adhesive sheet 2b, attaching the semiconductor wafer W, and attaching the support 3 to the adhesive layer (X1). The semiconductor wafer W is attached so that the circuit surface, that is, the surface W1, becomes the adhesive layer (X2) side. The semiconductor wafer W may be a silicon wafer, or a wafer of gallium arsenide, silicon carbide, sapphire, lithium tantalate, lithium niobate, gallium nitride, indium phosphide, etc., or a glass wafer. The thickness of the semiconductor wafer W before grinding is usually 500-1000 μm. The circuits on the surface W1 of the semiconductor wafer W can be formed by conventional methods such as etching and lift-off.

The material of the support 3 may be appropriately selected in consideration of the required characteristics such as mechanical strength, heat resistance, etc., in accordance with the type and processing content of the object to be processed. As the material of the support 3, for example, metal materials such as SUS; non-metallic inorganic materials such as glass and silicon wafers; epoxy resin, ABS resin, acrylic resin, engineering plastic, super engineering plastic, polyimide resin , Polyamide imide resin and other resin materials; composite materials such as glass epoxy resin, etc. Among them, SUS, glass, silicon wafers are preferred. As said engineering plastics, nylon, polycarbonate (PC), polyethylene terephthalate (PET), etc. are mentioned, for example. Examples of the above-mentioned super engineering plastics include polyphenylene sulfide (PPS), polyether sulfide (PES), polyether ether ketone (PEEK), and the like.

The support 3 is preferably attached to the entire surface of the adhesive layer (X1). Therefore, the area of the surface of the support 3 attached to the adhesive surface side of the adhesive layer (X1) is preferably greater than the area of the adhesive surface of the adhesive layer (X1). In addition, it is preferable that the surface of the support 3 attached to the adhesive surface side of the adhesive layer (X1) is flat. Although the shape of the support 3 is not particularly limited, it is preferably a plate shape. Although the thickness of the support 3 may be appropriately selected in consideration of the required characteristics, it is preferably 20 μm or more and 50 mm or less, and more preferably 60 μm or more and 20 mm or less.

(Step 2A) Step 2A is a step of performing one or more processes selected from a grinding process and a singulation process on the object to be processed. As one or more processing selected from grinding processing and singulation processing, for example, grinding processing using a grinder or the like can be mentioned; by blade cutting method, laser cutting method, stealth cutting (registered trademark) method, and cutting edge Single chip processing such as method, invisible tip cutting method, etc. Among them, it is suitable for the singulation processing by the invisible cutting method, the grinding processing and the singulation processing by the knife-point cutting method, the grinding processing and the singulation processing by the invisible tip cutting method, and it is more suitable for Grinding processing and singulation processing by the knife-point cutting method, grinding processing and singulation processing by the invisible tip cutting method.

The stealth dicing method is a method of singulating the semiconductor wafer by forming a modified region inside the semiconductor wafer by the irradiation of laser light, and using the modified region as a starting point for dividing. The modified region formed by the semiconductor wafer is the part that is embrittled by multiphoton absorption, and the semiconductor wafer is expanded by applying stress to the direction parallel to the wafer surface and the direction of wafer expansion. As the starting point, the qualitative region is split into a semiconductor wafer by cracking and stretching toward the surface and back of the semiconductor wafer. That is, the modified region is formed along the dividing line when singulated. The modified region is inside the semiconductor wafer, and is formed inside the semiconductor wafer by the irradiation of laser light that matches the focus. The incident surface of the laser light can be the surface of the semiconductor wafer or the back surface. In addition, the laser light incident surface may be a surface where the adhesive sheet is attached. In this case, the laser light is irradiated on the semiconductor wafer through the adhesive sheet.

The tip cutting method is also known as the DBG method (Dicing Before Grinding). The knife-edge dicing method is to form a groove in the semiconductor wafer with a depth shallower than its thickness in advance along a predetermined dividing line, and then grind the back of the semiconductor wafer to at least reach the groove on the grinding surface to make it thin And monolithic method. The groove reaching the grinding surface becomes a notch penetrating the semiconductor wafer, and the semiconductor wafer is divided into a semiconductor wafer by the notch. The pre-formed groove is usually provided on the surface (circuit surface) of the semiconductor wafer, and can be formed by, for example, dicing using a wafer dicing device equipped with a conventionally known dicing blade.

The invisible tip cutting method is also known as the SDBG method (Stealth Dicing Before Grinding). The invisible tip dicing method is the same as the invisible dicing method. Although it is a method of singulating the semiconductor wafer by forming a modified region inside the semiconductor wafer by the irradiation of laser light, and using the modified region as the starting point for dividing the semiconductor wafer One type, but the point system for grinding the semiconductor wafer to thin the semiconductor wafer and singulate the semiconductor wafer is different from the stealth dicing method. Specifically, a semiconductor wafer with a modified region is ground on the back side and thinned. At this time, pressure is applied to the semiconductor wafer, and the modified region is used as a starting point, toward the bonding with the adhesive layer of the semiconductor wafer. Attach the surface and extend the cracks, and the semiconductor wafers are singulated into semiconductor wafers. Still, although the thickness of the grinding after forming the modified area can be the thickness that reaches the modified area, even if it cannot be rigorously ground to reach the modified area, it can be ground to a position close to the modified area and cut by the processing pressure of grinding stones, etc. .

When the semiconductor wafer W is singulated by the knife-edge dicing method, it is preferable to attach the surface W1 of the semiconductor wafer W to the adhesive layer (X2) in step 1A to form a groove in advance. On the other hand, when the semiconductor wafer W is singulated by the stealth tip dicing method, the semiconductor wafer W attached to the adhesive layer (X2) in step 1A can be irradiated with laser light to form a modified region in advance. The semiconductor wafer W attached to the adhesive layer (X2) can be irradiated with laser light to form a modified region.

4 is a cross-sectional view illustrating a step of forming a plurality of modified regions 5 by using the laser light irradiation device 4 for the semiconductor wafer W attached to the adhesive layer (X2). The laser light is irradiated from the back side W2 of the semiconductor wafer W, and a plurality of modified regions 5 are formed inside the semiconductor wafer W at approximately equal intervals.

5 is a diagram illustrating that the back surface W2 of the semiconductor wafer W forming the modified region 5 is ground by a grinder 6, and the modified region 5 is cut as a starting point to thin the semiconductor wafer W and singulate it into plural pieces. A cross-sectional view of the steps of a semiconductor wafer CP. For the semiconductor wafer W forming the modified region 5, for example, the support 3 supporting the semiconductor wafer W is fixed on a fixed table such as a chuck base, and the back surface W2 of the semiconductor wafer W is ground.

The thickness of the semiconductor wafer CP after grinding is preferably 5 to 100 μm, more preferably 10 to 45 μm. In addition, when the grinding process and the singulation process are performed by the invisible tip dicing method, it is easier to set the thickness of the semiconductor wafer CP obtained by grinding to 50 μm or less, more preferably 10 to 45 μm. The size of the semiconductor chip CP after grinding in a plan view is preferably less than 600 mm ² , more preferably less than 400 mm ² , and still more preferably less than 300 mm ² . Still, the so-called plan view refers to viewing along the thickness direction. The shape of the singulated semiconductor chip CP in plan view may be a square or a rectangular shape or other elongated shape.

(Step 3A) Step 3A is a step of attaching a thermosetting film to the surface opposite to the adhesive layer (X2) of the object to be processed. 6 is a cross-sectional view illustrating the step of attaching the thermosetting film 7 provided with the support sheet 8 to the surface of the plurality of semiconductor wafers CP obtained by the aforementioned processing on the opposite side of the adhesive layer (X2).

The thermosetting film 7 is a thermosetting film obtained by forming a resin composition containing at least a thermosetting resin, and is used as an adhesive when the semiconductor chip CP is mounted on a substrate. The thermosetting film 7 may contain a curing agent for the above-mentioned thermosetting resin, a thermoplastic resin, an inorganic filler, a curing accelerator, etc., if necessary. As the thermosetting film 7, for example, thermosetting films generally used as die bonding films, die bonding films, and the like can be used. Although the thickness of the thermosetting film 7 is not particularly limited, it is usually 1 to 200 μm, preferably 3 to 100 μm, and more preferably 5 to 50 μm. The support sheet 8 may be one that can support the thermosetting film 7, and examples thereof include resins, metals, paper materials, and the like as the base material (Y) included in the adhesive sheet of one aspect of the present invention.

As a method of attaching the thermosetting film 7 to a plurality of semiconductor chips CP, for example, a method by lamination can be cited. The lamination can be carried out while heating or without heating. The heating temperature during lamination is preferably "a temperature lower than the expansion initiation temperature (t)" from the viewpoint of suppressing the expansion of thermally expandable particles and the viewpoint of suppressing the thermal change of the object. , More preferably "expansion initiation temperature (t)-5°C" or less, still more preferably "expansion initiation temperature (t) -10°C" or less, and still more preferably "expansion initiation temperature (t)- Below 15°C.

(Step 4A) Step 4A is a step of heating the adhesive sheet to a temperature above the expansion initiation temperature (t) and below 120°C to separate the adhesive layer (X1) from the support. 7 is a cross-sectional view illustrating the step of heating the adhesive sheet 2b to separate the adhesive layer (X1) and the support 3.

The heating temperature in step 4A is above the expansion start temperature (t) of the thermally expandable particles, and is below 120°C, preferably "a higher temperature than the expansion start temperature (t)", more preferably "expansion The initial temperature (t) + 2°C" or higher, more preferably the "swelling initial temperature (t) + 4°C" or higher, and still more preferably the "swelling initial temperature (t) + 5°C" or higher. In addition, the heating temperature in step 4A is preferably "expansion start temperature (t) + 50" in the range of 120°C or less from the standpoint of energy saving and suppression of heat change during heating and peeling. °C" or less, more preferably "expansion initiation temperature (t) + 40 °C" or less, and still more preferably "expansion initiation temperature (t) + 20 °C" or less. The heating temperature in step 4A is from the viewpoint of suppressing the thermal change of the object to be adhered, in the range above the expansion initiation temperature (t), preferably 115°C or lower, more preferably 110°C or lower, and still more preferably Below 105°C.

(Step 5A) Step 5A is a step of separating the adhesive layer (X2) from the aforementioned object to be processed. 8 is a cross-sectional view illustrating the step of separating the adhesive layer (X2) and a plurality of semiconductor chips CP. The method of separating the adhesive layer (X2) and the plurality of semiconductor chips CP may be appropriately selected according to the type of the adhesive layer (X2). For example, when the adhesive layer (X2) is an adhesive layer whose adhesive force is reduced by energy ray irradiation, the adhesive layer (X2) may be irradiated with energy ray to reduce the adhesive force and then separate.

Through the above-mentioned steps 1A to 5A, a plurality of semiconductor wafers CP attached to the thermosetting film 7 are obtained. Next, it is preferable to divide the thermosetting film 7 to which a plurality of semiconductor wafers CP are attached into the same shape as the semiconductor wafer CP to obtain the semiconductor wafer CP with the thermosetting film 7. As a method of dividing the thermosetting film 7, for example, methods such as laser cutting, spreading, and melting by laser light can be applied. FIG. 9 shows a semiconductor wafer CP divided into a thermosetting film 7 having the same shape as the semiconductor wafer CP.

For the semiconductor chip CP with the thermosetting film 7, further, if necessary, an expansion step of expanding the distance between the semiconductor chips CP, a re-arrangement step of arranging a plurality of semiconductor chips CP of the expanded interval, and a plurality of semiconductor chips After the reversal step of reversing the front and back of the CP, the thermosetting film 7 is attached (die bonded) to the substrate. Then, by thermally curing the thermosetting film, the semiconductor wafer and the substrate can be fixed.

The manufacturing method of one aspect of the present invention may be the manufacturing method A, which does not include step 3A. When step 3A is not included, it may replace step 4A and include the following step 4A'. Step 4A': The step of heating the adhesive sheet above the expansion initiation temperature (t) and separating the adhesive layer (X1) from the support

As the adhesive sheet of one aspect of the present invention, when a double-sided adhesive sheet is used, the manufacturing method of the semiconductor device of the first aspect may be a manufacturing method including the following steps 1B to 4B (hereinafter also referred to as "manufacturing method B") . Step 1B: A step of attaching an additional object to the adhesive layer (X1) of the adhesive sheet, and attaching a support to the adhesive layer (X2) of the aforementioned adhesive sheet Step 2B: A step of performing one or more processing selected from grinding processing and singulation processing on the aforementioned processing object Step 3B: A step of attaching a thermosetting film with thermosetting properties to the surface opposite to the adhesive layer (X1) of the object to be processed Step 4B: The step of heating the adhesive sheet to a temperature higher than the expansion initiation temperature (t) and lower than 120°C to separate the adhesive layer (X1) from the object to be processed

Steps 1B to 3B are described by replacing the adhesive layer (X1) described in steps 1A to 3A with the adhesive layer (X2), and the adhesive layer (X2) with the adhesive layer (X1).

Step 4B is a step of heating the adhesive sheet to a temperature above the expansion start temperature (t) and below 120°C to separate the adhesive layer (X1) from the object to be processed. The heating conditions such as the heating temperature of the adhesive sheet in step 4B are the same as those described in step 4A. Through step 4B, a plurality of semiconductor chips attached to the thermosetting film are obtained. Then, in the same manner as in the case of the above-mentioned manufacturing method A, the thermosetting film is divided to obtain a semiconductor wafer with the thermosetting film.

Manufacturing method B may include step 5B of separating the adhesive layer (X2) from the aforementioned support after step 4B. The method of separating the adhesive layer (X2) and the support may be appropriately selected according to the type of the adhesive layer (X2). For example, when the adhesive layer (X2) is an adhesive layer whose adhesive force is reduced by energy ray irradiation, the adhesive layer (X2) may be irradiated with energy ray to reduce the adhesive force and then separate.

The manufacturing method of one aspect of the present invention may be manufacturing method B, which does not include step 3B. When step 3B is not included, it may replace step 4B and include the following step 4B'. Step 4B': The step of heating the adhesive sheet to the expansion initiation temperature (t) or higher to separate the adhesive layer (X1) from the object to be processed

＜Manufacturing method of other aspects of semiconductor device＞ The method of manufacturing a semiconductor device of the present invention is not limited to the method of manufacturing a semiconductor device of the first aspect described above, and may be a method of manufacturing a semiconductor device of another aspect different from the first aspect. As an example of a method of manufacturing a semiconductor device of another aspect, a method of using the adhesive sheet of one aspect of the present invention as one of the manufacturing steps as a temporary fixing sheet for inspecting an inspection object can be cited. Examples of inspections performed on inspection objects include optical microscopes, defect inspections using lasers (for example, garbage inspection, surface flaw inspection, wiring pattern inspection, etc.), and surface inspections by visual inspection. Examples of inspection objects include semiconductor wafers, semiconductor wafers, compound semiconductors, semiconductor packages, electronic parts, LED elements, sapphire substrates, displays, and panel substrates. When the adhesive sheet of one aspect of the present invention is used as a temporary fixing sheet for inspecting an inspection object, inspection can be performed with a plurality of inspection objects attached to the adhesive layer (X1) of the adhesive sheet. After the inspection, for example, a part of the adhesive layer (X1) to which the plurality of inspection objects are attached may be locally heated, and the specific inspection object attached to the part may be selectively heated to peel off. At this time, since the adhesive sheet of one aspect of the present invention can be peeled off by heating at low temperature, even if the workability and energy saving of the heating peeling operation are excellent, and the inspection object is easily changed by heat, it can be suppressed. The heating during peeling causes the thermal change of the inspection object.

As another example of a method of manufacturing a semiconductor device of another aspect, a method of separating a processing object attached to another sheet from the other sheet using the adhesive sheet of one aspect of the present invention can be cited. For example, although a plurality of semiconductor chips with extended intervals on the expansion tape are attached to the adhesive surface of the expansion tape, the operation of selecting these chips one by one is complicated. According to the method for manufacturing a semiconductor device of one aspect of the present invention, the adhesive layer (X1) of the adhesive sheet of one aspect of the present invention is attached to the exposed surfaces of the plurality of semiconductor chips attached to the expansion tape , Then, by peeling off the expansion tape from the plurality of semiconductor wafers, a plurality of semiconductor wafers can be separated from the expansion tape at a time. Through the above-mentioned steps, a plurality of semiconductor chips attached to the adhesive sheet of one aspect of the present invention are obtained. The plurality of semiconductor chips can then be easily separated by heating the adhesive layer (X1) to above the expansion start temperature (t) of the thermally expandable particles. At this time, since the adhesive sheet of one aspect of the present invention can be peeled off by heating at low temperature, even if it is a heat peeling operation, it has excellent workability and energy saving, and it is easy to change due to heat. The heating during peeling results in the thermal change of the body. The separated semiconductor wafers can be transferred to other adhesive sheets, and once separated, they can be used for the re-arrangement step of aligning the semiconductor wafers. [Example]

Although the following examples are described in more detail with respect to the present invention, the present invention is not limited to the following examples. In the following description, the so-called "non-expandable adhesive layer (X1')" means an adhesive layer that does not contain heat-expandable particles, and does not contain the adhesive layer of the adhesive sheet produced in the comparative example described later , And the adhesive layer of thermally expandable particles made for the measurement of shear storage elastic modulus G'is equivalent to the non-expandable adhesive layer (X1'). The physical property values of the following synthesis examples and examples are the values measured by the following methods.

[Mass average molecular weight (Mw)] Using a gel permeation chromatography device (manufactured by Tosoh Co., Ltd., product name "HLC-8020"), it was measured under the following conditions, and the value measured in terms of standard polystyrene was used. (Measurement conditions) ･Column: Connected to "TSK guard column HXL-L", "TSK gel G2500HXL", "TSK gel G2000HXL" and "TSK gel G1000HXL" (all manufactured by Tosoh Corporation) ･Column temperature: 40℃ ･Developing solvent: Tetrahydrofuran ･Flow rate: 1.0mL/min

[Thickness of each layer] The constant pressure thickness tester (model: "PG-02J", standard specification: in accordance with JIS K6783, Z1702, Z1709) manufactured by Teclock Co., Ltd. was used for measurement.

[Average particle diameter (D ₅₀ ) and 90% particle diameter (D ₉₀ ) of thermally expandable particles] A laser diffraction particle size distribution measuring device (for example, manufactured by Malvern, product name "Master Sizer 3000") is used to measure The particle distribution of thermally expandable particles before expansion at 23°C. In addition, the cumulative volume frequency calculated from the smaller particle diameter of the particle distribution is equivalent to 50% and 90% of the particle diameter, respectively, as "average particle diameter (D ₅₀ ) of thermally expandable particles" and "average particle diameter of thermally expandable particles". 90% particle diameter (D ₉₀ )".

[Storage elastic modulus E’ of base material (Y)] A substrate (Y) cut into a length of 5 mm × a width of 30 mm was used as a test sample, and a dynamic viscoelasticity measuring device (manufactured by TA Instruments, product name "DMAQ800") was used to set the test start temperature at 0°C and the test end temperature at 200°C. Measure the storage elastic modulus E'at the specified temperature under the conditions of a heating rate of 3°C/min, a vibration number of 1 Hz, and an amplitude of 20 μm.

[Shear storage elastic modulus G’(23) of adhesive layer (X1) at 23℃] The adhesive layer (X1) with a diameter of 8mm × a thickness of 3mm is used as a test sample, and a viscoelasticity measuring device (manufactured by Anton Paar, device name "MCR300") is used, and the test start temperature is 0°C and the test end temperature is 300°C , The temperature rise rate is 3°C/min, and the number of vibrations is 1 Hz. The shear storage elastic modulus G'(23) at 23°C is measured by the torsion shear method.

[Shear storage elasticity G'of non-expandable adhesive layer (X1')] In order to measure the shear storage elastic modulus G'that excludes the influence of thermally expandable particles, a non-expandable adhesive layer that will have the same composition as the adhesive layer (X1) except that no thermally expandable particles is included in each example (X1') As a sample for measuring the shear storage elastic modulus of the adhesive layer (X1) corresponding to each example, the shear storage elastic modulus G'was measured. In addition, the shear storage elastic modulus G'of the non-expandable adhesive layer (X1') produced in the comparative example was also measured by this evaluation method. The non-expandable adhesive layer (X1') is set to be 8mm in diameter x 3mm in thickness as a test sample, and a viscoelasticity measuring device (manufactured by Anton Paar, device name "MCR300") is used to test the starting temperature at 0°C and the test At the end temperature of 300°C, the heating rate of 3°C/min, and the number of vibrations of 1Hz, the shear storage elastic modulus G'(23) at 23°C was measured by the torsion shear method, and the initial expansion of the thermally expandable particles Shear storage elasticity G'(t) at temperature (t). In addition, the so-called sample for measurement of shear storage elastic modulus, that is, the expansion start temperature (t) of the heat-expandable particles of the non-expandable adhesive layer (X1'), means an example of the sample for measurement of corresponding shear storage elastic modulus The expansion start temperature (t) of the heat-expandable particles contained in the adhesive layer (X1), which will be described later in this embodiment, means 88°C. In addition, since the adhesive sheet produced in the comparative example did not have the expansion initiation temperature (t), the shear storage elastic modulus G'at 88°C was measured in the same manner as in the example.

Synthesis example 1 (Synthesis of urethane acrylate prepolymer) By mixing 100 parts by mass of polypropylene glycol with a mass average molecular weight (Mw) of 3,000 (solid content conversion value; the same below), 4 parts by mass of hexamethylene diisocyanate, and 0.02 parts by mass of dioctyltin dilaurate, in Stir at 80°C for 6 hours to obtain a reactant (hereinafter also referred to as "unmodified prepolymer"). When measuring the IR spectrum of the obtained reactant by infrared spectroscopy, it was confirmed that the isocyanate group almost disappeared. Then, 1 part by mass of 2-isocyanate ethyl acrylate was mixed with respect to the total amount of the obtained reactant, and stirred at 80° C. for 3 hours to obtain a urethane acrylate-based prepolymer. When measuring the IR spectrum of the obtained urethane acrylate prepolymer by infrared spectroscopy, it was confirmed that the isocyanate group almost disappeared. The mass average molecular weight (Mw) of the obtained urethane acrylate prepolymer was 25,000.

Examples 1-22 (Production of polymerizable composition) The components described in Table 1 were mixed with the blending composition described in Table 1 to obtain solvent-free polymerizable compositions. The details of each component described in Table 1 are as follows. [Polymerizable vinyl monomer] 2EHA: 2-ethylhexyl acrylate ((a1-1) component) IBXA: Isobornyl acrylate ((a1-2) component) HEA: 2-hydroxyethyl acrylate ( (a1-3) component) 4HBA: 4-hydroxybutyl acrylate ((a1-3) component) [Multifunctional (meth)acrylate monomer] Trifunctional monomer: Isocyanurate ethylene oxide modified three Acrylate (component (a1-4)) [Multifunctional (meth)acrylate prepolymer] Urethane acrylate prepolymer: Prepared in Synthesis Example 1 (component (a2)) Polypropylene resin Acrylate-based prepolymer: "KANEKA XMAP (registered trademark) RC100C" (manufactured by Zhongyuan Chemical Industry Co., Ltd., polyacrylic acid-based prepolymer with acrylic groups at both ends, mass average molecular weight (Mw): 21,500 ) (Component (a2)) [Photopolymerization initiator] 1-Hydroxycyclohexyl phenyl ketone [Thermally expandable particles] AkzoNobel, product name "Expancel (registered trademark) 031-40" (DU type), expanded Starting temperature (t) = 88℃, average particle diameter (D ₅₀ ) = 12.6 μm, 90% particle diameter (D ₉₀ ) = 26.2 μm, as shown in Table 1 "Adhesive layer (X1) or non-expandable adhesive The "-" in "the composition of the layer (X1')" means that the component is not blended.

(Production of Adhesive Sheet) Using the solvent-free polymerizable composition used in the above-mentioned production, an adhesive sheet was produced in the following procedure. The solvent-free polymerizable composition is coated on the peeling treatment surface of a polyethylene terephthalate (PET)-based release film (manufactured by LINTEC Co., Ltd., product name "SP-PET381031", thickness: 38μm), The polymerizable composition layer is formed. The polymerizable composition layer was irradiated with ultraviolet rays under the conditions of an illuminance of 150 mW/cm ² and a light quantity of 100 mJ/cm ² to perform preliminary polymerization. The thickness of the polymerizable composition layer was adjusted so that the thickness of the resulting adhesive layer (X1) became the thickness described in Table 1. Next, on the exposed surface of the polymerizable composition layer, a polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., COMOSHINE (registered trademark), article number "A4300" as a base material (Y) is attached , Thickness: 50 μm), to obtain a laminate in which the release film, the polymerizable composition layer, and the substrate (Y) are laminated in this order. Furthermore, the storage elastic modulus E'(23) of the base material (Y) at 23°C is 3.0×10 ⁹ Pa, and the storage elastic modulus E'( of the thermally expandable particles of the base material (Y) at the expansion start temperature (t) t) is 2.4×10 ⁹ Pa. The laminate obtained above was irradiated with ultraviolet rays under the conditions of 200 mW/cm ² illuminance and 2,000 mJ/cm ² (irradiated 4 times 500 mJ/cm ² ) from the side of the release film to form an adhesive layer (X1). The film, the adhesive layer (X1) and the substrate (Y) are laminated in this order. Note that the above-mentioned illuminance and light intensity during ultraviolet irradiation are values measured using an illuminance/light meter (manufactured by EIT, product name "UV Power Puck II").

Comparative examples 1 to 5 Except that the composition of the adhesive layer (X1) in Example 1 was changed to the composition described in Table 1, the rest was carried out in the same manner as in Example 1, to obtain a release film and a non-expandable adhesive layer (X1') Adhesive sheet laminated in sequence with substrate (Y).

Comparative example 6 Except that in Example 5, the urethane acrylate-based prepolymer was not blended into the adhesive main agent, the same procedure was performed as in Example 5 to prepare a solvent-free polymerizable composition. Next, the solvent-free polymerizable composition was applied to a polyethylene terephthalate (PET) release film (manufactured by LINTEC Co., Ltd., product name "SP-PET381031", thickness: 38μm). On the treated surface, but the viscosity is too low to form the desired thickness of the coating film.

Comparative example 7 Except that in Example 5, 2-ethylhexyl acrylate and isobornyl acrylate were not blended in the adhesive main agent, and trifunctional monomers were not blended in the solvent-free polymerizable composition, the others are the same as the examples 5 In the same manner, a solvent-free polymerizable composition is prepared. Next, the solvent-free polymerizable composition was applied to a polyethylene terephthalate (PET) release film (manufactured by LINTEC Co., Ltd., product name "SP-PET381031", thickness: 38μm). The surface is treated, but the viscosity is too high to form a coating film.

Comparative example 8 Except in Example 5, the urethane acrylate prepolymer blended in the adhesive main agent was substituted, and the unmodified prepolymer prepared in Synthesis Example 1, other than In Example 5, the same was performed to produce an adhesive sheet. The resulting adhesive sheet has low cohesive force, and in the evaluation of self-peelability, there is no self-peeling. When peeling force is applied to make it peel off, the cohesion is broken and a paste remains.

For the adhesive sheets produced in the following examples, the following evaluations were performed. The evaluation results are shown in Table 2.

[Measurement of the adhesive force of the adhesive layer (X1) at 23℃ before thermal expansion] Remove the peeling film from the adhesive layer (X1) which is cut into 25mm×250mm adhesive sheets. The exposed surface of the adhesive layer (X1) is the mirror surface of the silicon mirror wafer. According to JIS Z0237: 2000, 2kg The rubber roller is attached, and then it is left to stand for 20 minutes in an environment of 23°C and 50%RH (relative humidity). After standing under the above conditions, use a tensile tester (manufactured by A&D Co., Ltd., product name "Tensilon (registered trademark)") at 23°C and 50%RH (relative humidity), according to JIS Z0237: 2000 , Measure the adhesion force by 180° peeling method at a tensile speed of 300mm/min.

[Measurement of adhesive force at 23℃ after thermal expansion of adhesive layer (X1)] In addition, the above-mentioned test sample was placed on the hot plate so that the silicon mirror wafer was in contact with the hot plate, and the adhesive sheet side was the side not in contact with the hot plate. Heat for 1 minute at ℃, and after standing for 60 minutes in a standard environment (23℃, 50%RH (relative humidity)), the adhesive layer is measured by 180° peeling method according to JIS Z0237: 2000 at a tensile speed of 300 mm/min. (X1) Adhesion. However, in order to determine that the adhesive force is too small when the adhesive sheet is fixed, it will be unintentionally peeled off, and when it is difficult to measure the adhesive force, the adhesive force is set to 0N/25mm.

[Assessment of self-detachability] Remove the peeling film from the adhesive layer (X1) cut into 50mm×50mm adhesive sheets. The exposed adhesive layer (X1) is the mirror surface of the silicon mirror wafer. According to JIS Z0237: 2000, 2kg The rubber rollers were bonded together and then left to stand for 20 minutes in an environment of 23°C and 50%RH (relative humidity) as a test sample. Next, the test sample is placed on the hot plate so that the silicon mirror wafer is in contact with the hot plate, and the adhesive sheet side is the side not in contact with the hot plate, and is 100°C or higher than the expansion start temperature of the thermally expandable particles. The maximum heating time is 60 seconds. The ratio (%) of the peeled area of the adhesive sheet at the time of heating for 60 seconds (peeled area×100/area of the entire adhesive sheet) was calculated and evaluated based on the following criteria. A: The adhesive sheet is completely peeled off within 60 seconds. B: Heating for 60 seconds, and the peeled area is 30% or more and less than 100%. C: Heating for 60 seconds, and the peeled area is less than 30%. In addition, for the person who evaluated "A", the time (seconds) required to fully peel off was measured.

[Measurement method of adhesive force and self-peeling property of non-expandable adhesive layer (X1') at 23°C] Regarding the adhesive force and self-peelability of the non-expandable adhesive layer (X1') made in Comparative Examples 1 to 5 at 23°C, the adhesive force of the above-mentioned adhesive layer (X1) at 23°C is In the description of the method for measuring peelability, the adhesive layer (X1) is replaced with a non-expandable adhesive layer (X1'). However, the so-called "adhesive force at 23°C of the non-expandable adhesive layer (X1')" in Table 2 "before thermal expansion" and "after thermal expansion" mean that in Comparative Examples 1 to 5, "equivalent to implementation Before the heat treatment of the thermal expansion treatment of the example" and "after the heat treatment equivalent to the thermal expansion treatment of the embodiment", the so-called "heating treatment equivalent to the thermal expansion treatment of the embodiment" means [thermal expansion of the adhesive layer (X1) Then heat treatment described in the measurement of adhesion at 23°C].

From Table 2, it is understood that the adhesive sheets of Examples 1-22, even when the adhesive layer is formed with energy-ray polymerizable components, can form the adhesive layer well, and it has sufficient properties before peeling by heating. It is effective, but it can also obtain sufficient self-peeling performance during thermal peeling. In addition, it is understood that these adhesive sheets can adjust the adhesive force and self-peelability by adjusting the composition of the polymerizable composition and the thickness of the adhesive layer (X1). On the other hand, none of the adhesive sheets of Comparative Examples 1 to 5 could be peeled off by heating.

1a, 1b, 2a, 2b: adhesive sheet 10, 10a, 10b: peeling material 3: Support 4: Laser light irradiation device 5: Modified area 6: Grinder 7: Thermosetting film 8: Support flakes W: semiconductor wafer W1: Semiconductor wafer and circuit surface of semiconductor wafer W2: Semiconductor wafer and the back side of semiconductor wafer CP: Semiconductor wafer

[Figure 1] is a cross-sectional view showing an example of the structure of the adhesive sheet of the present invention. [Fig. 2] A cross-sectional view showing an example of the structure of the adhesive sheet of the present invention. Fig. 3 is a cross-sectional view illustrating an example of the steps of the method of manufacturing the semiconductor device of the present invention. Fig. 4 is a cross-sectional view illustrating an example of the steps of the manufacturing method of the semiconductor device of the present invention. Fig. 5 is a cross-sectional view illustrating an example of the steps of the manufacturing method of the semiconductor device of the present invention. Fig. 6 is a cross-sectional view illustrating an example of the steps of the method of manufacturing the semiconductor device of the present invention. Fig. 7 is a cross-sectional view illustrating an example of the steps of the manufacturing method of the semiconductor device of the present invention. Fig. 8 is a cross-sectional view illustrating an example of the steps of the method of manufacturing the semiconductor device of the present invention. Fig. 9 is a cross-sectional view illustrating an example of the steps of the method of manufacturing the semiconductor device of the present invention.

1a, 1b: Adhesive sheet

10: Stripping material

X1: Adhesive layer

Y: substrate

Claims (15)

An adhesive sheet comprising a base material (Y), an adhesive layer (X1) of a polymer containing energy ray polymerizable components and thermally expandable particles, The aforementioned polymer as the aforementioned energy-ray polymerizable component is a polymerizable composition containing a monomer (a1) having an energy-ray polymerizable functional group and a prepolymer (a2) having an energy-ray polymerizable functional group, and is irradiated with energy Polymer made of thread. The adhesive sheet according to claim 1, wherein the component (a2) contains a prepolymer having two energy ray polymerizable functional groups and the energy ray polymerizable functional groups at both ends . The adhesive sheet according to claim 1 or 2, wherein the mass average molecular weight (Mw) of the component (a2) is 10,000 to 350,000. The adhesive sheet according to any one of claims 1 to 3, wherein, in the polymerizable composition, the content ratio of the (a2) component and the (a1) component [(a2)/(a1)], The quality standard is 10/90～70/30. The adhesive sheet according to any one of claims 1 to 4, wherein the polymerizable composition contains, as the component (a1), a monomer having three or more energy ray polymerizable functional groups. The adhesive sheet according to any one of claims 1 to 5, wherein the polymerizable composition contains a monomer having an energy ray polymerizable functional group and a hydroxyl group as the component (a1). The adhesive sheet according to any one of claims 1 to 6, wherein the polymerizable composition contains a monomer having an energy ray polymerizable functional group and an alicyclic hydrocarbon group as the component (a1). The adhesive sheet according to any one of claims 1 to 7, wherein the thickness of the adhesive layer (X1) at 23°C is 5 to 150 μm. The adhesive sheet according to any one of claims 1 to 8, wherein the expansion start temperature (t) of the thermally expandable particles is 50 to 110°C. The adhesive sheet as described in any one of claims 1 to 9, which has a substrate (Y), and an adhesive layer (X1) provided on one side of the substrate (Y), and The adhesive layer (X2) on the other side of the base material (Y). A method for manufacturing an adhesive sheet, which is a method for manufacturing an adhesive sheet as described in any one of claims 1 to 10, characterized by The method of forming the adhesive layer (X1) includes the step of irradiating the polymerizable composition containing the energy-ray polymerizable component and the thermally expandable particles with energy rays to form the polymer of the energy-ray polymerizable component. A method of manufacturing a semiconductor device, comprising: attaching an object of work to an adhesive sheet as described in any one of claims 1 to 10, Perform one or more processing selected from grinding processing and singulation processing on the aforementioned processing object, After performing the aforementioned treatment, the step of heating the aforementioned adhesive sheet to above the aforementioned expansion starting temperature (t) to expand the adhesive layer (X1). A method of manufacturing a semiconductor device, which includes the following steps 1A to 5A, Step 1A: A step of attaching an additional object to the adhesive layer (X2) of the adhesive sheet as described in claim 10, and attaching a support to the adhesive layer (X1) of the aforementioned adhesive sheet Step 2A: A step of performing one or more processing selected from grinding processing and singulation processing on the aforementioned processing object Step 3A: A step of attaching a thermosetting film with thermosetting properties to the surface opposite to the adhesive layer (X2) of the object to be processed Step 4A: The step of heating the adhesive sheet to a temperature above the expansion initiation temperature (t) and below 120°C to separate the adhesive layer (X1) from the support Step 5A: A step of separating the adhesive layer (X2) from the aforementioned object to be processed. The method of manufacturing a semiconductor device according to claim 13, wherein the adhesive layer (X2) is cured by irradiation of energy rays to reduce the adhesive force, The aforementioned step 5A is a step of irradiating the adhesive layer (X2) with energy rays to harden the adhesive layer (X2) and separating the adhesive layer (X2) from the aforementioned object to be processed. A method of manufacturing a semiconductor device, which includes the following steps 1B to 4B, Step 1B: A step of attaching an additional object to the adhesive layer (X1) of the adhesive sheet as described in claim 10, and attaching the support to the adhesive layer (X2) of the adhesive sheet Step 2B: A step of performing one or more processing selected from grinding processing and singulation processing on the aforementioned processing object Step 3B: A step of attaching a thermosetting film with thermosetting properties to the surface opposite to the adhesive layer (X1) of the object to be processed Step 4B: A step of heating the adhesive sheet to a temperature above the expansion initiation temperature (t) and below 120°C to separate the adhesive layer (X1) from the object to be processed.

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