Adhesive sheet and method for peeling an object from an adhesive sheet

Abstract

The present application can pick up an object held by an adhesive sheet having an adhesive layer with unevenness on the surface with a milder operation. An adhesive sheet having a substrate and an adhesive layer with unevenness on the surface. The adhesive layer has energy ray reactivity, and the value of (tan δ at 50°C) / (tan δ at 30°C) of the adhesive layer after energy ray irradiation is 1.30 or more.

Description

Technical Field

[0001] This invention relates to an adhesive sheet and a method for peeling an object from the adhesive sheet, and more particularly to the manufacture of a semiconductor chip. Background Technology

[0002] Adhesive sheets can be used to temporarily hold objects. For example, they can be used to transfer an object to a desired location.

[0003] On the other hand, to improve production efficiency, it is also required that the object be easily peeled off from the adhesive sheet. For example, Patent Document 1 discloses a method that reduces the adhesive strength of a smooth first adhesive film by irradiating it with ultraviolet light when an electronic component is attached to it. In the method described in Patent Document 1, the electronic component is further pressed onto a second adhesive film, and then the first adhesive film is peeled off, thereby transferring the electronic component from the first adhesive film to the second adhesive film. Furthermore, Patent Document 2 discloses an adhesive sheet configured to facilitate easy peeling of the object, capable of extending along the surface direction, and having an adhesive layer with an uneven surface.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-61529

[0007] Patent Document 2: International Publication No. 2024 / 063124 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] The adhesive sheets described in Patent Documents 1 and 2 are intended to possess both the object-holding force of an adhesive sheet and the ease of peeling an object from the adhesive sheet. Especially when handling fragile objects such as thin semiconductor chips, there is a need to further reduce the force applied to pick up the object. The adhesive sheets disclosed in Patent Documents 1 and 2 still have room for improvement in terms of ease of peeling.

[0010] One embodiment of the present invention enables the picking up of objects held by adhesive sheets having an adhesive layer having an uneven surface with gentler operation.

[0011] Solution for solving the problem

[0012] Through repeated and in-depth research, the inventors discovered that by appropriately designing the adhesive layer of the adhesive sheet, it is easier to pick up objects from the adhesive sheet, thereby solving the above-mentioned technical problems. After further repeated research, the inventors completed this invention.

[0013] That is, the embodiments of the present invention relate to the following [1] to

[10] .

[0014] [1] An adhesive sheet having a substrate and an adhesive layer having an uneven surface, the adhesive layer being energy ray reactive, and the value of (loss tangent (tanδ) at 50°C) / (tanδ at 30°C) of the adhesive layer after irradiation by energy rays being 1.30 or more.

[0015] [2] According to the adhesive sheet described in [1], in the adhesive layer after being irradiated by energy rays, the temperature at which the rise of tanδ stops when heated from 0°C is greater than 55°C.

[0016] [3] An adhesive sheet according to any one of [1] to [2], wherein the adhesive layer contains an acrylate copolymer having energy-curable groups.

[0017] [4] According to the adhesive sheet described in [3], the acrylate copolymer has a monomer containing an energy-curable group as a (meth)acrylate monomer, and a (meth)acrylate monomer crosslinked with other (meth)acrylate monomers.

[0018] [5] An adhesive sheet according to any one of [1] to [4], wherein the adhesive sheet is capable of extending along the surface direction.

[0019] [6] The adhesive sheet according to any one of [1] to [5], wherein the height of the protrusion of the adhesive layer is 1µm or more.

[0020] [7] An adhesive sheet according to any one of [1] to [6], wherein the adhesive layer has a plurality of protrusions, the plurality of protrusions being defined by recesses and separated from each other, and the spacing between the plurality of protrusions being more than 1 µm and less than 100 µm.

[0021] [8] An adhesive sheet according to any one of [1] to [7], wherein the adhesive layer has a plurality of protrusions of uniform height.

[0022] [9] An adhesive sheet according to any one of [1] to [8], wherein it further comprises a release layer having a surface with ...

[0023]

[10] A peeling method, the peeling method being a method of peeling an object from an adhesive sheet, the adhesive sheet being an adhesive sheet according to any one of [1] to [9] in which the object is held in an adhesive layer, the peeling method comprising: an irradiation step of irradiating the adhesive layer with energy rays; an expansion step of expanding the adhesive sheet in a surface direction; and a peeling step of peeling the object from the adhesive layer of the adhesive sheet.

[0024] Invention Effects

[0025] One embodiment of the present invention enables the picking up of objects held by adhesive sheets having an adhesive layer having an uneven surface with gentler operation.

[0026] Other features and advantages of the invention will become apparent from the following description with reference to the accompanying drawings. It should be noted that, in the drawings, the same or identical components are labeled with the same reference numerals. Attached Figure Description

[0027] The accompanying drawings, which are included in and form a part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0028] Figure 1 This is a cross-sectional view of an adhesive sheet according to one embodiment.

[0029] Figure 2A This is a cross-sectional view showing an example of the unevenness of the adhesive layer before expansion.

[0030] Figure 2B This is a cross-sectional view showing an example of the unevenness of the extended adhesive layer.

[0031] Figure 3A This is a top view showing an example of the unevenness of the adhesive layer before expansion.

[0032] Figure 3B This is a top view showing an example of the unevenness of the extended adhesive layer.

[0033] Figure 3C This is a top view showing another example of the unevenness of the adhesive layer.

[0034] Figure 4A This is a cross-sectional view showing an example of the unevenness or roughness of the adhesive layer.

[0035] Figure 4B This is a cross-sectional view showing an example of the unevenness or roughness of the adhesive layer.

[0036] Figure 4C This is a cross-sectional view showing an example of the unevenness or roughness of the adhesive layer.

[0037] Figure 5A This is a diagram illustrating the method of spreading adhesive sheets.

[0038] Figure 5B This is a diagram illustrating the method of spreading adhesive sheets.

[0039] Figure 6 This is a flowchart of a method for manufacturing an adhesive sheet according to one embodiment.

[0040] Figure 7This is a flowchart of a stripping method for one implementation. Detailed Implementation

[0041] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments are not intended to limit the invention as defined in the claims. Furthermore, not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more features from the plurality of features described in the embodiments can be combined arbitrarily. In addition, identical or identical components are labeled with the same reference numerals, and repeated descriptions are omitted.

[0042] (definition)

[0043] In this specification, the mass-average molecular weight (Mw) and number-average molecular weight (Mn) are values ​​converted from standard polystyrene determined using size exclusion chromatography, specifically values ​​based on JIS K7252-1:2016. Furthermore, in this specification, "(meth)acrylic acid" refers to both "acrylic acid" and "methacrylic acid," as do other similar terms.

[0044] In this specification, when one or more lower limits and one or more upper limits are specified for a numerical range (e.g., a range of content), it can be understood that any combination of the lower and upper limits is specified. For example, the specification that "preferably 1 or more, more preferably 2 or more, further preferably 3 or more, preferably 9 or less, more preferably 8 or less, and further preferably 7 or less" indicates that the numerical range can be any one of 1 or more and 9 or less, 1 or more and 8 or less, 1 or more and 7 or less, 2 or more and 9 or less, 2 or more and 8 or less, 2 or more and 7 or less, 3 or more and 9 or less, 3 or more and 8 or less, and 3 or more and 7 or less. Furthermore, in this specification, unless otherwise specified, parts by mass and percentage by mass represent ratios based on the mass of the solid components.

[0045] (Composition of adhesive sheet)

[0046] An adhesive sheet according to one embodiment of the present invention includes a substrate 120 and an adhesive layer 110 having an uneven surface. The adhesive sheet can be used as a transfer sheet for temporarily holding an object and transferring it to a transfer target. For example, the adhesive sheet can be used to receive an object held by another holding substrate, temporarily hold the object, and transfer the object to a desired position at the transfer target. The substrate 120 can support the adhesive layer 110. Hereinafter, a schematic diagram of an adhesive sheet as one embodiment will be referred to. Figure 1 Explain the composition of this adhesive sheet.

[0047] (Substrate)

[0048] The substrate 120 functions as a support for the adhesive layer 110. The substrate 120 is located on the side of the adhesive layer 110 opposite to the side with the uneven surface.

[0049] In one embodiment, the adhesive sheet can extend along the surface direction. From this perspective, a flexible substrate can be used as the substrate 120. Furthermore, using a flexible substrate as the substrate 120 improves cushioning when holding an object, facilitates the lamination of the adhesive sheet, or allows the adhesive sheet to be rolled up. For example, a resin film can be used as the substrate 120. A resin film is a film using a resin-based material as the main material; it can be formed from a resin material or may contain additives in addition to a resin material. The resin film can also be laser-transmissive.

[0050] Specific examples of resin membranes include polyethylene membranes such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE); polypropylene membranes, polybutene membranes, polybutadiene membranes, poly(4-methyl-1-pentene) membranes, ethylene-norbornene copolymer membranes, and norbornene resin membranes; ethylene copolymer membranes such as ethylene-vinyl acetate copolymer membranes, ethylene-(meth)acrylic acid copolymer membranes, and ethylene-(meth)acrylic acid copolymer membranes; polyvinyl chloride membranes and vinyl chloride copolymer membranes; polyester membranes such as polyethylene terephthalate membranes and polybutylene terephthalate membranes; polyurethane membranes; polyimide membranes; polystyrene membranes; polycarbonate membranes; and fluoropolymer membranes. Furthermore, membranes containing mixtures of two or more materials, cross-linked membranes formed by cross-linking the resins that form these membranes, and modified membranes such as ionomer membranes can also be used. In addition, the substrate 120 can also be a laminated film made of two or more resin films.

[0051] From the viewpoint of facilitating the expansion of the adhesive sheet, the substrate 120 is preferably a polyolefin film or a vinyl chloride copolymer film. Examples of polyolefin films include polyethylene films, polypropylene films, and copolymers containing unsubstituted olefins such as ethylene or propylene as structural units, such as ethylene-methacrylic acid copolymers (EMAA). Examples of vinyl chloride copolymer films include vinyl chloride-vinylidene chloride copolymer films, vinyl chloride-vinyl acetate copolymer films, and vinyl chloride-ethylene copolymer films. The form of this copolymer is not particularly limited and can be any of a block copolymer, random copolymer, alternating copolymer, or graft copolymer. It should be noted that these films may also contain other resin components or additives.

[0052] The thickness of the substrate 120 is not particularly limited, but from the viewpoint of balancing support and winding, it is preferably 10µm or more, more preferably 25µm or more, even more preferably 40µm or more, and on the other hand, it is preferably 500µm or less, more preferably 200µm or less, even more preferably 150µm or less, even more preferably 120µm or less, and particularly preferably 90µm or less.

[0053] To facilitate uniform expansion of the adhesive sheet, the tensile modulus of the substrate 120 is preferably 50 MPa or more, more preferably 80 MPa or more, even more preferably 120 MPa or more, preferably 2500 MPa or less, more preferably 1000 MPa or less, and even more preferably 500 MPa or less. In this specification, the tensile modulus is measured according to JIS K7161-1:2014.

[0054] Similarly, in order to facilitate the expansion of the adhesive sheet, the elongation at break of the substrate 120 is preferably 105% or more, more preferably 110% or more, and even more preferably 115% or more. In this specification, the elongation at break is measured according to JIS K 7127:1999.

[0055] (Adhesive layer)

[0056] The adhesive layer 110 is an adhesive layer. As described above, the adhesive layer 110 has uneven surfaces. It should be noted that the adhesive sheet may have two or more adhesive layers 110. For example, the adhesive sheet may be a laminate of one or more adhesive layers 110.

[0057] The composition of adhesive layer 110 will be described below. However, the composition of adhesive layer 110 is not limited to what is shown below.

[0058] (Resin)

[0059] The adhesive layer 110 may contain a resin. The adhesive layer 110 may contain one type of resin or two or more types of resin. Examples of resins contained in the adhesive layer 110 include rubber resins such as polyisobutylene resins, polybutadiene resins, and styrene-butadiene resins, acrylic resins, urethane resins, polyester resins, olefin resins, silicone resins, and polyvinyl ether resins. The adhesive layer may be heat-resistant; examples of materials for such a heat-resistant adhesive layer 110 include polyimide resins and silicone resins. The adhesive layer 110 may contain copolymers having two or more structural units. The form of such copolymers is not particularly limited; they may be any of block copolymers, random copolymers, alternating copolymers, and graft copolymers.

[0060] The resin contained in the adhesive layer 110 is preferably an adhesive resin that has adhesive properties on its own. In one embodiment, the resin is a polymer having a mass-average molecular weight (Mw) of 10,000 or more. From the viewpoint of improving holding power, the mass-average molecular weight (Mw) of the resin is preferably 10,000 or more, more preferably 70,000 or more, and even more preferably 140,000 or more. Furthermore, from the viewpoint of suppressing the storage modulus to a predetermined value or less, it is preferably 2,000,000 or less, and even more preferably 1,200,000 or less. Furthermore, from the viewpoint of improving holding power, the number-average molecular weight (Mn) of the resin is preferably 10,000 or more, more preferably 50,000 or more, and even more preferably 100,000 or more. Furthermore, from the viewpoint of suppressing the storage modulus to a predetermined value or less, it is preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,200,000 or less. In this specification, the mass-average molecular weight (Mw) and number-average molecular weight (Mn) of the adhesive layer 110 containing the energy-ray reactive resin refer to the mass-average molecular weight (Mw) and number-average molecular weight (Mn) before the crosslinking reaction by energy-ray irradiation, unless otherwise specified.

[0061] Furthermore, from the viewpoint of improving the holding power of the adhesive layer 110, the glass transition temperature (Tg) of the resin is preferably -75°C or higher, more preferably -70°C or higher, preferably 5°C or lower, and more preferably -20°C or lower. When the resin has two or more structural units, the glass transition temperature (Tg) of the resin can be calculated using the Fox formula. The Tg of the monomer that derives the structural unit used in this case can be the value recorded in a polymer datasheet or adhesive manual.

[0062] The amount of resin contained in the adhesive layer 110 can be appropriately set according to the required adhesive strength of the adhesive layer 110, relative to the total amount of the components constituting the adhesive layer 110. Preferably, it is 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, preferably 99.99% by mass or less, more preferably 99.95% by mass or less, even more preferably 99.90% by mass or less, even more preferably 99.80% by mass or less, even more preferably 99.50% by mass or less.

[0063] In one embodiment, the resin contained in the adhesive layer 110 may contain a thermoplastic resin. When a thermoplastic resin is used, heating softens the resin, making it easy to form unevenness in the adhesive layer 110, and furthermore, it is easy to maintain the unevenness formed by cooling. Examples of thermoplastic resins include rubber-based resins, acrylic resins, urethane resins, and olefin resins. Examples include polybutadiene thermoplastic elastomers using butadiene as a monomer, styrene thermoplastic elastomers using styrene as a monomer, and acrylic thermoplastic elastomers using (meth)acrylic acid or (meth)acrylate as monomers.

[0064] In one embodiment, the adhesive layer 110 is energy-reactive. For example, in addition to resin, the adhesive layer 110 may also contain energy-reactive components. Alternatively, the adhesive layer 110 may also contain an energy-reactive resin. In this specification, the energy-reactive nature of the adhesive layer 110 means that the storage modulus of the adhesive layer 110 is increased by irradiation with energy rays. The type of energy ray is not particularly limited; examples include ultraviolet light, electron beams, or ionizing radiation. As an energy ray, ultraviolet light is preferred, meaning that the adhesive layer 110 is preferably ultraviolet-reactive.

[0065] The reactive component of energy rays can be a compound with polymerizable functional groups. These polymerizable functional groups are cross-linked functional groups formed by irradiation with energy rays. Examples of such polymerizable functional groups include groups containing multiple bonds, oxobutyl groups, and epoxy groups. Furthermore, examples of groups containing multiple bonds include alkenyl groups such as vinyl and allyl, and groups containing double bonds such as (meth)acryloyl. This cross-linking of polymerizable functional groups occurs in the presence of a suitable polymerization initiator or cross-linking agent.

[0066] The component reactive to energy rays can be a difunctional or polyfunctional monomer having polymerizable functional groups as described above. Examples of such monomers include poly(meth)acrylates such as difunctional (meth)acrylates. Specific examples of poly(meth)acrylates include cycloalkyl di(meth)acrylates such as tricyclodecanediethanol diacrylate.

[0067] Energy-reactive resins refer to resins whose storage modulus is increased by irradiation with energy rays. Energy-reactive resins can be energy-curable resins. It should be noted that in this specification, resins whose storage modulus has already been increased by irradiation with energy rays, and whose storage modulus will not increase even with further irradiation with energy rays (e.g., UV-curable resins after curing) are not included in energy-reactive resins.

[0068] Energy-reactive resins are, for example, polymers having energy-curable groups. This polymer can be a copolymer. Furthermore, the polymer can have side chains with energy-curable groups. Examples of energy-curable groups include the aforementioned groups containing multiple bonds, oxobutyl groups, and epoxy groups. Preferred examples of energy-curable groups include alkenyl groups such as vinyl and allyl, and groups containing carbon-carbon double bonds such as (meth)acryloyl. By irradiating such an energy-reactive resin with energy rays, the energy-curable groups of the polymer can be cross-linked. In one embodiment, the energy-curable group is an ultraviolet-curable group.

[0069] Thus, when the adhesive layer 110 contains an energy-reactive resin, compared to the case where the adhesive layer 110 contains a combination of resin and energy-reactive components, the storage modulus of the adhesive layer 110 is more easily increased when irradiated with energy rays. Furthermore, it is easier to simultaneously achieve both the holding force of the adhesive layer 110 on the object before energy ray irradiation and the ease with which the object can be peeled off the adhesive layer 110 after energy ray irradiation. Moreover, by using an energy-reactive resin in the adhesive layer 110, it is easier to maintain a high adhesive force before energy ray irradiation while simultaneously improving the retention of the adhesive layer 110's uneven shape.

[0070] In one embodiment, the main component of the adhesive layer 110 is an energy-reactive resin. From the viewpoint of reducing the adhesive strength after curing, the content of the polymer having energy-reactive groups is preferably 70% by mass or more, more preferably 80% by mass, and even more preferably 90% by mass or more, and on the other hand, 100% by mass or less, more preferably 99% by mass or more, and even more preferably 98% by mass or less, relative to the total amount of the components constituting the adhesive layer 110.

[0071] (Acrylic copolymers with energy-ray reactivity)

[0072] In one embodiment, the adhesive layer 110 comprises an acrylate copolymer. An acrylate copolymer is a copolymer having (meth)acrylate as a structural unit. This acrylate copolymer may be radioactive.

[0073] Examples of (meth)acrylates include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate, n-octyl methacrylate, n-nonyl methacrylate, isononyl methacrylate, decyl methacrylate, undecyl methacrylate, lauryl methacrylate, tridecyl methacrylate, myristyl methacrylate, pentadecyl methacrylate, palmitate methacrylate, heptadecanyl methacrylate, stearyl methacrylate, etc., where the alkyl group of the alkyl ester is a carbon atom. Alkyl methacrylates with chain structures of 1 to 18; cycloalkyl methacrylates such as isoborneol methacrylate and dicyclopentyl methacrylate; aralkyl methacrylates such as benzyl methacrylate; cycloalkenyl methacrylates such as dicyclopentenyl methacrylate; cycloalkenyl methacrylates such as dicyclopentenoxyethyl methacrylate; cycloalkenoxyalkyl methacrylates such as imide methacrylates; glycidyl methacrylates and other methacrylates containing glycidyl groups; hydroxyl-containing methacrylates such as methyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 3-hydroxybutyl methacrylate, 4-hydroxybutyl methacrylate; and methacrylates containing substituted amino groups such as N-methylaminoethyl methacrylate. Here, "substituted amino" refers to a group having a structure in which one or two hydrogen atoms of the amino group are replaced by a group other than a hydrogen atom. Acrylic ester copolymers can also be copolymers of acrylates and methacrylates.

[0074] Acrylic copolymers with energy-ray reactive properties can have monomers containing energy-ray curable groups as structural units. For example, acrylate copolymers can have side chains with energy-ray curable groups as described above. Examples of monomers containing energy-ray curable groups include (meth)acrylate monomers. Examples of (meth)acrylate monomers with energy-ray curable groups include (meth)acrylate monomers with energy-ray curable groups such as groups having carbon-carbon double bonds in the side chain via hydroxyl groups. For example, acrylate copolymers can also be copolymers of acrylates with energy-ray curable groups, acrylates without energy-ray curable groups, and methacrylates without energy-ray curable groups.

[0075] The acrylate copolymer can also be a cross-linked polymer. As described above, the surface of the adhesive layer 110 has an unevenness. Therefore, the adhesive layer 110 ideally has a storage modulus that can maintain the unevenness of the surface even before irradiation by energy rays. By using a cross-linked polymer as the acrylate copolymer, it is easy to maintain the unevenness of the surface of the adhesive layer 110.

[0076] For example, acrylate copolymers can have monomers crosslinked with other monomers as structural units. As a specific example, (meth)acrylate monomers can be crosslinked with other (meth)acrylate monomers via hydroxyl groups. Furthermore, the two (meth)acrylate monomers in an acrylate copolymer can also be crosslinked with each other using urethane. Thus, in addition to having monomers containing energy-curable groups as (meth)acrylate monomers, acrylate copolymers can also have (meth)acrylate monomers crosslinked with other (meth)acrylate monomers. Preferred examples of acrylate copolymers include copolymers of acrylates having energy-curable groups, acrylates crosslinked with other acrylate monomers, and copolymers of (meth)acrylate alkyl esters.

[0077] Acrylic copolymers may also contain (meth)acrylate monomers other than monomers containing energy-curable groups and monomers crosslinked with other monomers. Furthermore, acrylate copolymers may also contain monomers other than (meth)acrylates. For example, in addition to (meth)acrylates, acrylate copolymers may also have one or more monomers selected from itaconic acid, vinyl acetate, acrylonitrile, styrene, and N-hydroxymethylacrylamide as structural units. The combination and ratio of monomers constituting the acrylate copolymer can be selected according to the properties of the required adhesive layer 110.

[0078] Energy-reactive acrylate copolymers can be prepared by polymerization using monomers containing energy-reactive groups. Furthermore, energy-reactive acrylate copolymers can also be prepared by modifying acrylate copolymers to introduce energy-reactive groups.

[0079] For example, as the modified material, an acrylate copolymer having a monomer with an energy-curable group can be used. The (meth)acrylate monomer with an energy-curable group can be, for example, a (meth)acrylate monomer having a specific functional group such as a hydroxyl group. In one embodiment, the modified acrylate copolymer comprises a hydroxyl-containing acrylate as a structural unit.

[0080] By reacting this acrylate copolymer with an energy-curing group introducer, energy-curing groups can be introduced into the (meth)acrylate monomer. As the energy-curing group introducer, a compound having a functional group that bonds to a specific functional group and an energy-curing group can be used. For example, the energy-curing group introducer can be a compound having an isocyanate group and an energy-curing group, such as ethyl 2-isocyanate methacrylate. By using such a compound, energy-curing groups can be introduced into the (meth)acrylate monomer via the hydroxyl group present in the (meth)acrylate monomer.

[0081] Here, the copolymerization rate of monomers in the acrylate copolymer that can introduce energy-curable groups is set as R. A %. Here, copolymerization rate represents the molar ratio of the monomer that can introduce energy-curable groups to the total number of monomers present in the acrylate copolymer. Furthermore, the equivalent of the energy-curable group introducer relative to the monomer that can introduce energy-curable groups is set as R. B %. Here, equivalence represents the molar ratio of the added energy-curable group introducer to the substituents in the acrylate copolymer that react with the energy-curable group introducer. When the monomer capable of introducing the energy-curable group has a hydroxyl group that reacts with the energy-curable group introducer, R B The percentage (%) indicates the molar ratio of the added energy-curable group introducer to the hydroxyl-containing monomers in the acrylate copolymer. However, in this specification, R... B The upper limit is set at 100%. That is, when an excessive amount of energy-curable group introducer is used on a monomer that can introduce energy-curable groups, R B Defined as 100%.

[0082] R A % and R B The product of % represents the copolymerization rate of monomers with introduced energy-curable groups in the acrylate copolymer when the monomers with introduced energy-curable groups react completely with the energy-curable group introducer. In one embodiment, from the viewpoint of sufficiently reducing the object-holding force of the adhesive layer 110 after energy-curable group irradiation, R A % and R B The product of % is 23.0% or more, more preferably 24.0% or more, and even more preferably 25.0% or more. On the other hand, in one embodiment, from the viewpoint of suppressing the positional shift of the object in the adhesive layer 110 after energy ray irradiation, R A % and R BThe product of % is 50.0% or less, more preferably 40.0% or less, even more preferably 30.0% or less, and particularly preferably 27.0% or less.

[0083] Here, from the viewpoint of sufficiently reducing the object-holding force of the adhesive layer 110 after irradiation by energy rays, R A The percentage is preferably 10% or more, more preferably 15% or more, further preferably 20% or more, and particularly preferably 25% or more. On the other hand, from the viewpoint of sufficiently improving the object-holding force of the adhesive layer 110 before irradiation by energy rays, R... A The percentage is preferably 50% or less, more preferably 40% or less, and even more preferably 30% or less.

[0084] Furthermore, from the viewpoint of sufficiently reducing the object-holding force of the adhesive layer 110 after irradiation by energy rays, R B The percentage is preferably 50% or more, more preferably 65% ​​or more, and even more preferably 75% or more. On the other hand, R... B % is below 100%.

[0085] Furthermore, crosslinked acrylate copolymers can be obtained by modifying the monomers of the acrylate copolymer to crosslink with each other. For example, an acrylate copolymer having monomers that can react with a crosslinking agent can be used as the modified material. The monomers that can react with the crosslinking agent can be, for example, (meth)acrylate monomers having specific functional groups such as hydroxyl groups. By reacting such an acrylate copolymer with a crosslinking agent, the (meth)acrylate monomers can be crosslinked with each other.

[0086] As crosslinking agents, compounds having two or more functional groups that bond with specific functional groups can be used. Examples of crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, and metal chelating crosslinking agents. Thermal crosslinking agents, which initiate the crosslinking reaction through heat treatment, can also be used. These crosslinking agents can be used alone or in combination of two or more.

[0087] Among these crosslinking agents, isocyanate-based crosslinking agents are preferred from the viewpoints of improving cohesion and maintaining the uneven shape, as well as from the viewpoints of availability. By using isocyanate-based crosslinking agents, the hydroxyl groups of (meth)acrylate monomers can be crosslinked with each other. Examples of isocyanate crosslinking agents include aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and phenyl dimethylene diisocyanate; alicyclic polyisocyanates such as dicyclohexylmethane-4,4'-diisocyanate, bicycloheptanane triisocyanate, cyclopentyl diisocyanate, cyclohexyl diisocyanate, methylcyclohexyl diisocyanate, methylene bis(cyclohexyl isocyanate), 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, and hydrogenated phenyl dimethylene diisocyanate; noncyclic aliphatic polyisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate; and other polyisocyanate compounds. In addition, as isocyanate crosslinking agents, examples include trimethylolpropane adduct-type modifiers of the polyisocyanate compound, biuret-type modifiers formed by reacting with water, and isocyanurate-type modifiers containing isocyanurate rings such as hexamethylene diisocyanate.

[0088] The amount of crosslinking agent used at this time is not particularly limited; for example, it can be in excess relative to the monomers in the copolymer before modification that can react with the crosslinking agent. In one embodiment, from the viewpoint of maintaining the unevenness of the surface of the adhesive layer 110, the amount of isocyanate crosslinking agent is preferably 1.5 parts by mass or more, more preferably 2 parts by mass or more, and even more preferably 2.5 parts by mass or more, relative to 100 parts by mass of the copolymer before modification. Furthermore, from the viewpoint of improving the object-holding strength of the adhesive layer 110, it is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less.

[0089] Furthermore, ray-reactive and crosslinked acrylate copolymers can be prepared by modifying acrylate copolymers having monomers with ray-reactive curable groups and monomers that can react with a crosslinking agent. Additionally, ray-reactive and crosslinked acrylate copolymers can also be prepared by modifying acrylate copolymers having monomers with ray-reactive curable groups and monomers that can react with a crosslinking agent. In this case, firstly, by modifying a portion of the monomers in the unmodified copolymer to introduce ray-reactive curable groups, an acrylate copolymer having monomers with ray-reactive curable groups and monomers that can react with a crosslinking agent can be prepared. Furthermore, by modifying this acrylate copolymer to crosslink another portion of the monomers, a ray-reactive and crosslinked acrylate copolymer can be prepared.

[0090] For example, such acrylate copolymers can be prepared by modifying acrylate copolymers with monomers containing hydroxyl groups. First, a portion of the hydroxyl groups can be modified using an isocyanate compound having a carbon-carbon double bond group in an amount less than the amount of hydroxyl groups in the copolymer before modification. Furthermore, another portion of the hydroxyl groups can be crosslinked with a urethane using an isocyanate crosslinking agent such as a polyisocyanate compound. In this case, in the modified copolymer, a portion of the hydroxyl groups in the monomer are modified to have carbon-carbon double bonds via urethane bonds. Additionally, in the modified copolymer, another portion of the hydroxyl groups in the monomer are modified to form urethane crosslinks.

[0091] In this case, from the viewpoint of sufficiently reducing the object retention force of the adhesive layer 110 after energy ray irradiation, the equivalent R of the energy ray curable group introducer relative to the monomer that can introduce the energy ray curable group is... B The percentage is preferably 50% or more, more preferably 65% ​​or more, and even more preferably 75% or more. On the other hand, from the viewpoint of easily maintaining the uneven shape of the adhesive layer 110 before energy ray irradiation, it is preferably 99% or less, more preferably 96% or less, and even more preferably 93% or less.

[0092] As described above, in one embodiment, the adhesive layer 110 comprises an acrylate copolymer. In the acrylate copolymer of one embodiment, the copolymerization rate of the monomers containing energy-curable groups is 23.0% or more and 50.0% or less. In this specification, the copolymerization rate of the monomers containing energy-curable groups in the acrylate copolymer is defined based on the raw material composition, specifically by the aforementioned R... A % and R B The product is expressed as a percentage. In acrylate copolymers, the preferred range for the copolymerization rate of monomers containing energy-curable groups is as described above: R. A % and R B The preferred range of the product of %.

[0093] It should be noted that the reaction between the monomer with the energy-curable group and the energy-curable group introducer may not be complete, and the unreacted energy-curable group introducer may be contained in the adhesive layer 110. In one embodiment, the actual copolymerization rate of the monomer containing the energy-curable group in the acrylate copolymer is 23.0% or more and 50.0% or less. In one embodiment, from the viewpoint of sufficiently reducing the object retention force of the adhesive layer 110 after energy irradiation, the actual copolymerization rate is more preferably 24.0% or more, and even more preferably 25.0% or more. On the other hand, from the viewpoint of suppressing the positional displacement of the object in the adhesive layer 110 after energy irradiation, the actual copolymerization rate is more preferably 40.0% or less, even more preferably 30.0% or less, and particularly preferably 27.0% or less. Here, in the acrylate copolymer, the actual copolymerization rate of the monomer containing the energy-curable group represents the molar ratio of the monomer having the energy-curable group to all the monomers present in the acrylate copolymer. This actual copolymerization rate can be determined by methods such as NMR (Nuclear Magnetic Resonance Spectroscopy) or thermal decomposition GC / MS.

[0094] From the viewpoint of improving holding power, the mass-average molecular weight (Mw) of the acrylate copolymer is preferably 10,000 or more, more preferably 70,000 or more, and even more preferably 140,000 or more. Furthermore, from the viewpoint of suppressing the storage modulus to a predetermined value or less, it is preferably 2,000,000 or less, and even more preferably 1,200,000 or less. Furthermore, from the viewpoint of improving holding power, the number-average molecular weight (Mn) of the resin is preferably 10,000 or more, more preferably 50,000 or more, and even more preferably 100,000 or more. Furthermore, from the viewpoint of suppressing the storage modulus to a predetermined value or less, it is preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,200,000 or less.

[0095] From the viewpoint of sufficiently reducing the object-holding force of the adhesive layer 110 after irradiation by energy rays, the content of the acrylate copolymer relative to the total amount of components constituting the adhesive layer 110 is preferably 70% by mass or more, more preferably 80% by mass, and even more preferably 90% by mass or more. On the other hand, the content of the acrylate copolymer relative to the total amount of components constituting the adhesive layer 110 is 100% by mass or less, or it may be 99% by mass or more, or it may be 98% by mass or less.

[0096] (Other components of the adhesive layer)

[0097] The adhesive layer 110 may also contain components other than resin. For example, the adhesive layer 110 may also contain one or more of a crosslinking agent, a photopolymerization initiator, an antioxidant, and other additives.

[0098] Examples of crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, and metal chelating crosslinking agents. These crosslinking agents can be used alone or in combination of two or more. The crosslinking agent can be selected based on the resin contained in the adhesive layer 110. The crosslinking agent can be a crosslinking agent for the resin contained in the adhesive layer 110. For example, the crosslinking agent can be a crosslinking agent for acrylic resin. It should be noted that the crosslinking agent referred to here refers to unreacted crosslinking agents contained in the adhesive layer 110. The substances described above can be used as crosslinking agents, for example.

[0099] The adhesive layer 110 may contain one crosslinking agent or two or more crosslinking agents. From the viewpoint of properly carrying out the crosslinking reaction, the content of the crosslinking agent in the adhesive layer 110 is preferably 1% by mass or more, more preferably 1.5% by mass or more, even more preferably 2% by mass or more, preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0100] Photopolymerization initiators initiate crosslinking reactions upon exposure to energy rays. In cases where the adhesive layer 110 contains an energy-reactive resin, further incorporating a photopolymerization initiator into the adhesive layer 110 allows the crosslinking reaction to proceed even with relatively low energy input.

[0101] Examples of photopolymerization initiators include 1-hydroxycyclohexylphenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzylphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, bibenzyl, biacetyl, 8-chloroanthraquinone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0102] The adhesive layer 110 may contain one polymerization initiator or two or more polymerization initiators. The content of the photopolymerization initiator in the adhesive layer 110 is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 2% by mass or less.

[0103] Examples of antioxidants include phenols such as hindered phenolic compounds, aromatic amines, sulfur compounds, and phosphorus compounds such as phosphate esters.

[0104] There are no particular limitations on other additives that the adhesive layer 110 may contain. Examples include UV absorbers such as benzotriazole compounds, oxazolamide compounds, or benzophenone compounds; light stabilizers such as hindered amines, benzophenones, or benzotriazoles; resin stabilizers such as imidazole resin stabilizers, dithiocarbamate resin stabilizers, phosphorus resin stabilizers, or thioester resin stabilizers; fillers, pigments, extenders, and softeners.

[0105] When the adhesive layer 110 contains these additives, the content of the additives in the adhesive layer 110 is preferably 0.0001% by mass or more, more preferably 0.01% by mass or more, particularly preferably 0.1% by mass or more, further preferably 1% by mass or more, preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0106] (Shape of the adhesive layer)

[0107] The adhesive layer 110 of this embodiment has an uneven surface. In one embodiment, the adhesive layer 110 has a plurality of protrusions on its surface, the plurality of protrusions being defined by recesses and separated from each other. The plurality of protrusions can be separated by recesses that span the entire continuous portion of the adhesive layer 110.

[0108] Figures 2A-2B This is a side view showing the shape of the adhesive layer 110. Figures 3A-3C This is a top view showing the shape of the adhesive layer 110. Figure 2A and Figure 3A An example of the adhesive layer 110 before expansion is shown. Figure 2B and Figure 3B An example of the expanded adhesive layer 110' is shown. Furthermore, Figures 2A-2B The image depicts an object 140 held by the protrusions 111 of the adhesive layer 110. On the other hand... Figures 3A-3C The object 140 held by the protrusion 111 is omitted.

[0109] like Figure 2A and Figure 3A As shown, the surface of the adhesive layer 110 may have protrusions 111 arranged regularly. Regular arrangement of protrusions means that the protrusions are arranged in a straight line at regular intervals. Alternatively, the protrusions 111 may be arranged in a way that varies regularly in interval. For example, the interval between protrusions in the center of the adhesive sheet may be short, while the interval between protrusions in the periphery of the adhesive sheet may be long. Furthermore, the protrusions may also be arranged irregularly.

[0110] Figure 3C This is a top view showing another shape of the adhesive layer 110. (Example) Figure 3C As shown, linear protrusions 111 may be provided on the surface of the adhesive layer 110. Figure 3C In the design, linear protrusions 111 of a certain width are arranged at certain intervals. The width or interval of the linear protrusions 111 can vary regularly, or the linear protrusions 111 can be arranged irregularly.

[0111] From the viewpoint of adjusting the holding force, the spacing P of the protrusions 111 before expansion is preferably 1µm or more, more preferably 5µm or more, further preferably 10µm or more, and even more preferably 15µm or more. On the other hand, from the viewpoint of increasing the contact area between the adhesive layer 110 and the object to improve the holding force, this spacing P is preferably 100µm or less, more preferably 75µm or less, even more preferably 50µm or less, even more preferably 35µm or less, and even more preferably 25µm or less. Here, the spacing P of the protrusions 111 refers to the distance between the center point of any chosen protrusion 111 and the center point of the other protrusion 111 closest to that protrusion 111. For example, in Figure 2A In the case where the protrusions 111 are arranged at regular intervals, the spacing P represents the distance between the center point of the protrusions 111 on a straight line and the center point of the protrusion 111 closest to that protrusion 111. When the protrusions 111 are arranged on multiple straight lines, the spacing P represents the distance between the center points of the protrusions on the straight line with the shortest spacing. In this specification, the interval between protrusions 111 refers to the interval between the centers of the protrusions.

[0112] The specific shape of the protrusion 111 is not particularly limited. For example, the protrusion 111 can have a pillar shape. As specific examples, the protrusion 111 can have a cylindrical shape, a prism shape, a conical shape, a pyramidal shape, a sphere shape, or a hemispherical shape. Furthermore, as mentioned above, the protrusion 111 can extend in a linear shape or in a wavy or other curved shape. Moreover, these protrusions 111 can be provided with a taper or a reverse taper.

[0113] Figure 4A This is a cross-sectional view of the adhesive layer 110 through the protrusion 111 and perpendicular to the surface of the adhesive layer 110 in one embodiment. Figure 4A The convex portion 111 shown has a taper, meaning that the convex portion 111 has a shape that tapers towards the front end. Furthermore, as... Figure 4B As shown, the front end of the protrusion 111 can be curved. This configuration further mitigates the impact when the object is held in place by the adhesive layer 110, thus allowing the adhesive layer 110 to easily hold the object without shifting. Alternatively, the front end of the protrusion can also be flat.

[0114] like Figure 4A As shown, the surface of the adhesive layer 110 may have flat recesses and protrusions 111 protruding from the recesses. Thus, the plurality of mutually separated protrusions 111 of the adhesive layer 110 may be defined by the recesses.

[0115] As another example, a protrusion can be like... Figure 4B The image shown is a hemispherical shape or part of a sphere. Furthermore, the protrusion 111 can be as follows: Figure 4C The image shows a T-shape. As another example, the protrusion 111 can be in the shape of an aggregation of multiple particles, a mushroom shape, a lotus leaf surface shape, or a needle shape. As yet another example, the surface of the adhesive layer 110 can be rough or fibrous; such a surface can also be described as having irregularities.

[0116] From the viewpoint of maintaining the holding force of the object, the width or diameter of each protrusion 111 is preferably 1µm or more, more preferably 2µm or more, further preferably 5µm or more, and even more preferably 10µm or more. On the other hand, from the viewpoint of improving the ease of peeling off the object, it is preferably 100µm or less, more preferably 50µm or less, even more preferably 30µm or less, and even more preferably 20µm or less. Here, the width and diameter of the protrusion 111 refer to the minimum distance and maximum distance, respectively, between two parallel lines tangent to both sides of the protrusion 111 on the surface of the recess. Figure 4A (represented by W in Chinese).

[0117] Furthermore, from the viewpoint of maintaining the holding force of the object, the area of ​​each protrusion 111 is preferably 10µm. 2 The above, more preferably 20µm 2 The above is further preferred to be 30µm. 2 That's all. On the other hand, from the viewpoint of improving the ease of peeling off the object, 2000µm is preferred. 2 Hereinafter, 1000µm is more preferred. 2 Hereinafter, 500µm is further preferred. 2 Below. Here, the area of ​​the convex portion 111 refers to the area of ​​the portion protruding from the surface of the concave portion ( Figure 4A In the case of a circle with diameter W, the area is...

[0118] In one embodiment, from the viewpoint of improving the ease of peeling off the object, the height of each protrusion 111 is preferably 1µm or more, more preferably 3µm or more, and even more preferably 5µm or more. On the other hand, from the viewpoint of improving the holding force of the object, the height of each protrusion 111 is preferably 20µm or less, more preferably 15µm or less, and even more preferably 10µm or less. This allows for variation in the holding force of the object. Here, the height of the protrusion 111 is... Figure 4AThe protrusions are denoted by H. Furthermore, in one embodiment, the adhesive layer 110 has a plurality of protrusions with uniform height. In another embodiment, the adhesive layer 110 may have: a first plurality of protrusions having a first uniform height and a second plurality of protrusions having different heights. Here, the second plurality of protrusions may have a second uniform height. For example, protrusion 111 may be composed of such first and second protrusions. In yet another embodiment, the adhesive layer 110 may have a plurality of protrusions with random heights.

[0119] Furthermore, from the viewpoint of maintaining the holding force of the object, the total area of ​​the protrusions 111 relative to the area of ​​the adhesive layer 110 is preferably 1% or more, more preferably 5% or more, even more preferably 10% or more, even more preferably 18% or more, and even more preferably 40% or more. On the other hand, from the viewpoint of improving the ease of peeling off the object, the total area of ​​the protrusions relative to the area of ​​the adhesive layer 110 is preferably 95% or less, more preferably 75% or less, and even more preferably 60% or less.

[0120] (Characteristics of the adhesive layer)

[0121] As described above, in one embodiment, the adhesive layer 110 is energy-ray reactive. Therefore, by irradiating the adhesive layer 110 with energy rays, the storage modulus of the adhesive layer 110 increases. Furthermore, by irradiating the adhesive layer 110 with energy rays, the adhesive force of the adhesive layer 110 decreases.

[0122] In one embodiment, after irradiation with energy rays, the temperature at which the rise of tanδ in the adhesive layer 110 stops when heated from 0°C is greater than 55°C. Preferably, the temperature at which the rise of tanδ stops is greater than 57°C, more preferably greater than 59°C. tanδ, also known as the loss tangent, is represented by tanδ = G'' / G'. Here, G' is the storage modulus. Furthermore, G'' is the loss modulus. The storage modulus and loss modulus of the adhesive layer 110 are determined by the torsional vibration method according to JIS K7244-7:2007. Specifically, a sample of the same material as the adhesive layer 110, having a cylindrical shape with a thickness of 1 mm and a diameter of 8 mm, is prepared. Using a dynamic viscoelasticity measuring device, vibration at 10 Hz is applied, and the measurement is performed while the sample temperature is raised from -30°C to 120°C, thereby determining the storage modulus and loss modulus of the sample. Thus, the storage modulus and loss modulus of the adhesive layer 110 can be determined. It should be noted that, in this specification, the adhesive layer 110 after energy ray irradiation refers to the adhesive layer 110 after irradiation with an amount of energy ray that completes the crosslinking reaction. Considering that the measured value of tanδ may contain noise, in this specification, when tanδ is measured at intervals of 0.2℃ or finer, the smallest X (where X is a positive integer) above the average value of tanδ between X-2.5℃ and X+2.5℃ is defined as the temperature at which the rise of tanδ stops.

[0123] The inventors of this application have discovered that by using an adhesive layer 110 whose tanδ rise stops at a temperature greater than 55°C, it is easier to pick up objects (especially thin objects) from the adhesive sheet. While not intended to limit the invention, the inventors believe the reasons are as follows: Generally, the increase in tanδ accompanying a rise in temperature reflects a decrease in the storage modulus. Therefore, since the temperature at which the rise in tanδ stops is greater than 55°C, it is expected that the storage modulus will remain stably high near normal conditions, i.e., room temperature. Therefore, it is believed that when picking up an object, the protrusions of the adhesive layer 110 are less likely to follow the object, thus making it easier to pick up the object from the adhesive sheet. Furthermore, it is believed that when picking up an object after the adhesive sheet has been expanded following energy ray irradiation, the shear stress between the protrusions of the adhesive layer 110 and the object will be greater during the expansion of the adhesive sheet, making it easier for the object to peel off from the adhesive layer 110. This is also believed to contribute to the effect of easily picking up objects from the adhesive sheet. Moreover, by maintaining a stably high storage modulus near room temperature, it is expected that even if the temperature of the adhesive layer 110 rises due to energy ray irradiation, it will still be easy to pick up the object from the adhesive sheet. Alternatively, when the temperature of the adhesive layer 110 rises significantly due to energy ray irradiation, the cooling time of the adhesive layer 110 can be shortened, thus potentially increasing productivity.

[0124] In one embodiment, after irradiation by energy rays, the value of (tanδ at 50°C) / (tanδ at 30°C) in the adhesive layer 110 is 1.30 or more. The value of (tanδ at 50°C) / (tanδ at 30°C) is preferably 1.40 or more, more preferably 1.50 or more, and even more preferably 1.60 or more.

[0125] The inventors of this application have discovered that by using an adhesive layer 110 with a value of (tanδ at 50°C) / (tanδ at 30°C) of 1.30 or higher, it is easy to pick up objects (especially thin objects) from the adhesive sheet. While not intended to limit the invention, the inventors believe the reason for this is as follows: Generally, an increase in tanδ with increasing temperature reflects a decrease in the storage modulus. Therefore, in cases where tanδ increases sharply with increasing temperature, it is expected that the storage modulus will remain stably high in normal conditions, i.e., near room temperature. Therefore, as described above, it is believed that the holding force of the adhesive layer 110 on the object decreases after irradiation with energy rays, making it easier to pick up the object from the adhesive sheet.

[0126] In one embodiment, the tanδ value of the adhesive layer 110 at 23°C after irradiation by energy rays is 0.25 or less. Preferably, the tanδ value at 23°C is 0.22 or less, and more preferably 0.18 or less.

[0127] The inventors of this application have discovered that by using an adhesive layer 110 with a tanδ value of 0.25 or less at 23°C, it is easy to pick up objects (especially thin objects) from the adhesive sheet. While not intended to limit the invention, the inventors believe the reason is as follows: In a normal environment, i.e., near room temperature, when the tanδ value is sufficiently low, it is expected that the storage modulus will remain stably high near that temperature. Therefore, as described above, it is believed that after irradiation with energy rays, the holding force of the adhesive layer 110 on the object decreases, making it easier to pick up the object from the adhesive sheet.

[0128] From the viewpoint of facilitating the pickup of objects (especially thin objects) from the adhesive sheet, the storage modulus of the adhesive layer 110 at 23°C after irradiation by energy rays is preferably 0.80 GPa or more, more preferably 1.0 GPa or more, even more preferably 1.2 GPa or more, and even more preferably 1.5 GPa or more. On the other hand, from the viewpoint of suppressing positional displacement of the object after irradiation by energy rays, the storage modulus of the adhesive layer 110 at 23°C after irradiation by energy rays is preferably 10 GPa or less, more preferably 7.0 GPa or more, even more preferably 5.0 GPa or less, and even more preferably 3.0 GPa or more.

[0129] Furthermore, from the viewpoint of improving the object's holding power, the energy storage modulus of the adhesive layer 110 before energy ray irradiation is preferably 100 MPa or less, more preferably 50 MPa or less, even more preferably 20 MPa or less, and particularly preferably 5.0 MPa or less.

[0130] Furthermore, in one embodiment, the adhesive sheet can be extended along the surface direction. Figure 2A and Figure 3A The adhesive layer 110 shown is deformed by extending the adhesive sheet to become Figure 2B and Figure 3B The adhesive layer 110' is shown. When comparing adhesive layer 110 and adhesive layer 110', the spacing P of each protrusion 111 in adhesive layer 110' increases due to expansion, and the number of protrusions 111 holding an object 140 decreases. As a result, the force holding the object 140 by the protrusions 111 in adhesive layer 110' is reduced compared to adhesive layer 110. Furthermore, by expanding the adhesive sheet, shear stress acts between the protrusions 111 and the object 140. The inventors of this application believe that this also leads to a reduction in the holding force of the protrusions 111 on the object 140. From the viewpoint of sufficiently reducing the holding force of the object, the adhesive sheet of one embodiment can be expanded by more than 1% in the surface direction (e.g., one direction or two orthogonal directions), and can also be expanded by more than 5%.

[0131] (Peeling layer)

[0132] Furthermore, the adhesive sheet of this embodiment can be as follows: Figure 1 As shown, a release tab 150 is in contact with the adhesive layer 110. Figure 1 For illustrative purposes, the adhesive layer 110 is shown separated from the release tab 150. (See diagram below.) Figure 1 As shown, the release tab 150 has a surface that is complementary to the surface of the adhesive layer 110.

[0133] The release tab 150 has a release layer 160. The release layer 160 is a layer that is easily peelable from the adhesive layer 110. The release layer 160 may have a surface that is complementary to the surface of the adhesive layer 110. That is, the release layer 160 has a recess 161, which has a shape complementary to the convex portion 111. However, the recess 161 does not necessarily have to have a shape complementary to the convex portion 111.

[0134] The release tab 150 may have a substrate 170 on a surface that does not contact the adhesive layer 110. This substrate 170 may be designed similarly to the substrate 120, but does not need to have the same composition or structure. Furthermore, the release tab 150 may have an undercoat (not shown) between the release layer 160 and the substrate 170.

[0135] (Other layers)

[0136] The sheet described above may also have layers other than the substrate 120 and the adhesive layer 110. For example, an adhesive layer may be further provided on the surface of the substrate 120 opposite to the adhesive layer 110. The sheet can be adhered to other objects via this adhesive layer. There is no particular limitation on the type of the further provided adhesive layer; for example, a common adhesive can be used to form the further provided adhesive layer.

[0137] (Manufacturing method of adhesive sheet)

[0138] There are no particular limitations on the manufacturing method of the adhesive sheet and adhesive layer 110. Referring hereafter... Figure 6 An example of a method for manufacturing adhesive sheets will be provided.

[0139] In S610, an adhesive composition is prepared as the material for the adhesive layer 110. The adhesive composition is prepared by adding an organic solvent to a raw material composition containing each component of the adhesive layer 110. The adhesive composition may, for example, contain the aforementioned ray-reactive acrylate copolymer. As explained above, an ray-reactive acrylate copolymer can be reacted with an ray-reactive group introducer to introduce ray-reactive groups into the monomer. The process of preparing the adhesive composition may include the process of preparing the ray-reactive acrylate copolymer as described above. In this case, the copolymerization rate R of the monomers in the acrylate copolymer that can introduce ray-reactive groups is... A %, and the equivalent R of the energy of the reaction, the curing group of the introducing agent. B As explained above.

[0140] Furthermore, the adhesive composition may comprise the aforementioned acrylate copolymer having monomers with energy-curable groups and monomers capable of reacting with a crosslinking agent. Additionally, the adhesive composition may comprise a crosslinking agent for crosslinking the monomers of the acrylate copolymer with each other.

[0141] Examples of organic solvents used in the preparation of adhesive compositions include toluene, ethyl acetate, and methyl ethyl ketone. Examples of solution coating methods include spin coating, spray coating, bar coating, doctor blade coating, roller coating, roller-knife coating, doctor blade coating, mold coating, gravure coating, and printing methods (e.g., screen printing and inkjet printing).

[0142] In S620 and S630, an adhesive layer with an uneven surface is formed on the substrate 120 using the adhesive composition prepared in S610. First, in S620, a layer of the adhesive composition is formed on the substrate 120. For example, the adhesive composition is coated onto the substrate 120 to form a coating film, and then dried, thereby forming a layer of the adhesive composition on the substrate 120.

[0143] In S630, unevenness is formed on the surface of the adhesive composition layer thus formed. There are no particular limitations on the process of creating the unevenness. For example, an embossing method can be used to create the unevenness on the surface of the layer. In the embossing method, a mold having uneven surfaces complementary to the desired unevenness can be used. Thus, an adhesive layer 110 with uneven surface is formed. Specifically, the adhesive composition layer can be pressed with a mold, the layer heated and maintained for a predetermined time, and then the material layer cooled and the mold removed. During heating, for example, the material layer can be heated to a temperature higher than the softening point of the adhesive composition layer. As a specific method for heating the material layer while pressing it with a mold, a method of vacuum laminating the adhesive composition layer provided on the substrate 120 with a mold can be listed. Furthermore, as the mold, a release sheet 150 having a release layer 160 with unevenness can be used as described above.

[0144] On the other hand, to improve the maintenance of the uneven shape, a crosslinking reaction can be carried out on the resin contained in the adhesive composition during or after the unevenness is formed on the surface of the adhesive composition layer. As explained above, in one embodiment where the adhesive composition contains an acrylate copolymer having monomers that can react with a crosslinking agent, the monomers can be crosslinked together by reacting the acrylate copolymer with the crosslinking agent. By carrying out the curing reaction of the adhesive composition layer, the storage modulus of the adhesive layer 110 can be increased, thus improving the maintenance of the uneven shape. As a specific example, the adhesive composition layer is cured while in contact with a mold having uneven surfaces that are complementary to the unevenness, thereby forming an adhesive layer 110 with an uneven surface. In the case where the adhesive composition layer contains a copolymer before crosslinking and a thermal crosslinking agent, the crosslinking reaction is carried out by pressing the material layer with a mold while heating, forming an adhesive layer 110 containing the crosslinked copolymer. By using the crosslinking reaction caused by heating, unreacted energy-curable groups can remain in the adhesive layer 110.

[0145] As another method, an adhesive layer 110 with a rough surface can be formed by spraying the adhesive composition. Furthermore, fillers can be added to the adhesive composition, and an adhesive layer 110 with a rough or fibrous surface can be formed by coating such a solution. As yet another method, a printing method such as inkjet printing can be used to coat the adhesive composition according to a desired pattern, thereby directly forming an adhesive layer 110 with an uneven shape on the substrate 120.

[0146] As another method, an adhesive layer 110 with an uneven surface can also be formed on the release sheet 150. As described above, the surface of the release sheet 150 can have an uneven surface that is complementary to the uneven surface of the adhesive layer 110. In this case, by providing a layer of adhesive composition on the uneven surface of the release sheet 150, an adhesive layer with an uneven surface (i.e., the interface between the adhesive layer 110 and the release sheet 150) can be formed. Moreover, the substrate 120 can be adhered to the surface of the adhesive layer 110 opposite to the uneven surface. In this way, the adhesive layer 110 can also be formed on the substrate 120.

[0147] (How to use adhesive sheets)

[0148] The adhesive sheet of this embodiment can be used to process objects. For example, the adhesive sheet of this embodiment can be used to temporarily hold an object. Furthermore, the adhesive sheet of this embodiment can be used to transfer objects. As a specific example, the adhesive sheet of this embodiment can be used to transfer a semiconductor chip obtained by cutting to a desired location.

[0149] Regarding the method for treating an object using the adhesive sheet of this embodiment, please refer to... Figure 7 The flowchart is explained.

[0150] (S710: Object retention)

[0151] In S710, the object is held on the adhesive layer of the adhesive sheet in this embodiment. It should be noted that the type of object is not particularly limited. The object can be, for example, a component. Examples of components include semiconductor chips such as LED chips, semiconductor chips with protective films, and semiconductor chips with die-attach film (DAF). Furthermore, the component can be a miniature light-emitting diode, a power device, a MEMS (Micro Electromechanical Systems) chip, or a controller chip, or a component thereof. Furthermore, the component can be a monolithic assembly of a wafer, panel, or substrate. For example, the component can have a circuit surface on which an integrated circuit with circuit objects such as transistors, resistors, and capacitors is formed. Furthermore, the component is not necessarily limited to a monolithic assembly; it can also be various non-monolithic wafers or various substrates.

[0152] Furthermore, there are no particular limitations on the size of the object. For example, a preferred size is 100 µm. 2 The above, more preferably 500µm 2 The above is further preferred to be 1000µm. 2 That's all. On the other hand, the preferred size of the object is 100mm. 2 The following is more preferably 25mm 2 Hereinafter, 1mm is further preferred. 2 the following.

[0153] Examples of wafers include silicon wafers, silicon carbide (SiC) wafers, and compound semiconductor wafers (such as gallium phosphide (GaP) wafers, gallium arsenide (GaAs) wafers, indium phosphide (InP) wafers, and gallium nitride (GaN) wafers). The size of the wafer is not particularly limited, but is preferably 6 inches (approximately 150 mm in diameter) or larger, more preferably 12 inches (approximately 300 mm in diameter) or larger. It should be noted that the shape of the wafer is not limited to a circle; for example, it can also be a square or rectangle.

[0154] Examples of panels include fan-out semiconductor packages (such as FOWLP or FOPLP). That is, the object being processed can be a semiconductor package before or after monolithization in fan-out semiconductor packaging manufacturing technology. The size of the panel is not particularly limited, but it can be, for example, a rectangular substrate of about 300 to 700 mm.

[0155] Examples of substrates include glass substrates, sapphire substrates, and compound semiconductor substrates.

[0156] In one embodiment, components are transferred from a holding substrate to an adhesive sheet, which holds the transferred components. For example, a semiconductor wafer can be bonded to a wafer substrate and then further diced. The components on the diced wafer substrate can then be bonded to the adhesive layer 110 of the adhesive sheet. Then, by applying external stimulation such as a laser, the adhesion between the wafer substrate and the components can be reduced. Through this process, components can be transferred from the wafer substrate to the adhesive sheet. Alternatively, components obtained by dicing a semiconductor wafer can be transferred to a holding substrate, thereby obtaining a holding substrate with components bonded to it. The components bonded to the holding substrate can then be transferred to the adhesive layer 110 of the adhesive sheet using the same method.

[0157] In another embodiment, an external stimulus can be used to detach an element from a retaining substrate. Specifically, the element is positioned relatively far away from the retaining substrate, while being relatively close to the adhesive sheet. Then, by contacting the element with the adhesive layer 110 of the adhesive sheet, the element detaches from the retaining substrate and is captured by the adhesive sheet. The type of external stimulus is not particularly limited; examples include energy application, cooling, expansion of the retaining substrate, and physical stimuli (e.g., pressing the back of the retaining substrate using a pin). By using one or more of these external stimuli, the bonding force between the retaining substrate and the element can be reduced, and the element can be separated from the retaining substrate. For example, laser irradiation can be used to separate the element from the retaining substrate (laser peeling). In this embodiment, pressure is generated between the element and the adhesive layer 110 when the separated element approaches the adhesive layer 110. However, because the surface of the adhesive layer 110 has irregularities, the pressure generated between the element and the adhesive layer 110 is mitigated, making it easier to capture the element at the desired location on the adhesive sheet.

[0158] In a further embodiment, the object held on the adhesive layer 110 of the adhesive sheet can be processed. The processing method is not particularly limited. For example, wiring formation, back metal formation, cleaning, plating, monolithization, thin-film forming, and sealing can be performed. For example, a semiconductor wafer can be bonded to the adhesive layer 110 of the adhesive sheet. Then, by dicing the semiconductor wafer on the adhesive layer 110, a device can be formed. In this way, the adhesive sheet can also hold the device.

[0159] (S720: Adhesion reduction treatment)

[0160] In step S720, the adhesive force of the adhesive layer 110 holding the object is reduced. To reduce the adhesive force, a process of irradiating the adhesive layer 110 with energy rays and an expansion process of extending the adhesive sheet along the surface direction can be performed. By irradiating the energy-reactive adhesive layer 110 with energy rays, the storage modulus of the adhesive layer 110 increases, and the adhesive force decreases. Furthermore, by extending the adhesive sheet along the surface direction, the holding force of the adhesive layer 110 on the object is reduced as described above.

[0161] The energy level of the radiation applied during the processing step is set according to the type of adhesive layer 110 and the desired adhesive strength. For example, when irradiating with ultraviolet light, the intensity of the ultraviolet light is preferably 20 mJ / cm², considering the need to sufficiently reduce adhesive strength. 2 The above, more preferably 100 mJ / cm 2 That's all. Furthermore, from the viewpoint of shortening processing time, the optimal UV light intensity is 1000 mJ / cm². 2 Below, 500 mJ / cm is more preferred. 2 the following.

[0162] In the expansion process, the adhesive sheet is expanded along the surface direction. There is no particular limitation on the method of expanding the adhesive sheet. For example, the adhesive sheet can be expanded in one direction, two directions, or multiple directions. There is also no particular limitation on the expansion rate of the adhesive sheet. For example, from the viewpoint of sufficiently reducing the holding force of the object, the expansion rate of the adhesive sheet in one direction can be 1% or more, or 5% or more. Furthermore, from the viewpoint of preventing the adhesive sheet from breaking, the expansion rate of the adhesive sheet in one direction can be 50% or less, or 20% or less. From the same viewpoint, the expansion rate of the adhesive sheet in two mutually orthogonal directions can be 1% or more, or 5% or more, or on the other hand, it can be 50% or less, or 20% or less.

[0163] As a specific example, the adhesive sheet can be expanded by fixing it to the frame and pressing the base against the adhesive sheet within the frame. See [reference needed]. Figures 5A-5B illustrate. Figure 5A This indicates that the adhesive sheet holds the object in a state of 140a to 140d. For example... Figure 5A As shown, the outer periphery of the adhesive sheet can be fixed to the frame 320. The shape of the frame 320 is not particularly limited. For example, the frame 320 can be a circular or rectangular frame member with an opening. In one embodiment, a circular annular frame is used as the frame. By using the annular frame, the adhesive sheet can be extended in all directions.

[0164] Then, by contacting the adhesive sheet fixed to the frame 320 with the base 310, further as... Figure 5B The displacement (pull-down) of the frame 320 towards the base 310 allows the adhesive sheet to expand. It should be noted that the structure of the base 310 is not particularly limited; for example, it can be cylindrical or cuboid. Furthermore, the base 310 can be mesh-like or annular. The frame 320 can be displaced relative to the base 310 at a speed of 0.1 mm / sec or more, or at a speed of 1 mm / sec or more. In this case, from the viewpoint of sufficiently reducing the holding force on the object, the amount of displacement of the frame 320, i.e., the pull-down amount, can be, for example, 1 mm or more, or 5 mm or more. On the other hand, from the viewpoint of suppressing breakage of the adhesive sheet, the amount of displacement of the frame 320 can be 30 mm or less, or 20 mm or less.

[0165] (S730: Peeling off an object)

[0166] After reducing the adhesive force of the adhesive layer 110, in S730, the object is peeled off from the adhesive layer 110 of the adhesive sheet. For example, the object can be peeled off from the adhesive layer 110 of the adhesive sheet after performing the processing step and the expansion step. There is no particular limitation on the method of peeling off the object. For example, the above method can be used as a method for transferring an object pasted on the holding substrate to the adhesive sheet. As an example, an adsorption member such as a vacuum chuck can be used to peel the object off from the adhesive layer 110 of the adhesive sheet. Then, the adsorbed object can be moved to the desired position at the transfer target. As shown in this embodiment, by reducing the holding force of the adhesive layer 110, the object can be peeled off from the adhesive layer 110 of the adhesive sheet without applying physical stimulation such as pressing with a pin from the opposite side of the adhesive layer 110 of the adhesive sheet. However, the object can also be peeled off from the adhesive layer 110 of the adhesive sheet while applying physical stimulation from the opposite side of the adhesive layer 110 of the adhesive sheet.

[0167] It should be noted that, according to the research of the inventors of this application, when attempting to peel an object from the adhesive layer 110, if the adsorption force is increased according to the holding force of the adhesive layer 110, the object, such as a component, is easily damaged. This is especially true when peeling thin objects such as components, where increased adsorption force makes the object more prone to breakage. On the other hand, if the adhesive force of the adhesive layer 110 is reduced, the holding force of the adhesive layer 110 on the object decreases. For example, when transferring a component obtained by cutting from a wafer substrate to the adhesive sheet, if the adhesive force of the adhesive layer 110 is low, a portion of the component may remain on the wafer substrate. In this embodiment, by using a process that reduces the adhesive force, both a high holding force of the adhesive layer 110 when holding the object on the adhesive sheet and a low holding force of the adhesive layer 110 when peeling the object from the adhesive sheet can be achieved simultaneously. From this viewpoint, the processing method and the adhesive sheet of this embodiment are suitable for processing thin objects. For example, the thickness of the object held by the adhesive sheet is preferably 50 µm or less, more preferably 30 µm or less, and even more preferably 10 µm or less.

[0168] By following the steps described above, an object can be transferred to any transfer target using an adhesive sheet. Furthermore, one embodiment of the present invention relates to a method for peeling an object from an adhesive sheet in which the object is held in an adhesive layer. This peeling method may include a step such as S720 to reduce adhesive strength, and a step such as S730 to peel the object off.

[0169] Furthermore, this peeling method can be used to manufacture electronic components or semiconductor devices with elements. For example, a method for manufacturing an article according to one embodiment of the present invention may include a step of peeling an object from an adhesive sheet according to the above-described peeling method, and a step of manufacturing the article by post-processing the object. Figure 7In the example, S740 performs post-processing steps on the object. The types of post-processing are not particularly limited. For example, wiring formation, back metal formation, cleaning, plating, monolithization, thin-film forming, and sealing can be performed.

[0170] Example

[0171] The present invention will now be described in more detail with reference to specific embodiments. However, the present invention is not limited to any of the embodiments described below.

[0172] The following compounds were used in the examples and comparative examples.

[0173] <(A) Ingredient: Acrylate copolymer>

[0174] The following substances are used as acrylate copolymers.

[0175] (A1) A butyl acrylate resin (monomer mass ratio: butyl acrylate / methyl methacrylate / 2-hydroxyethyl acrylate = 52 / 20 / 28) is reacted with 2-isocyanate ethyl methacrylate in a 90% equivalent amount relative to 2-hydroxyethyl acrylate, thereby introducing a substance with energy-curable groups on the polymer side chain via hydroxyl groups (copolymerization rate of monomers containing energy-curable groups: 25.6%, mass-average molecular weight (Mw): 520000, number-average molecular weight (Mn): 155000).

[0176] (A2) A butyl acrylate resin (monomer mass ratio: butyl acrylate / methyl methacrylate / 2-hydroxyethyl acrylate = 62 / 10 / 28) is reacted with 2-isocyanate ethyl methacrylate in an 80% equivalent amount relative to 2-hydroxyethyl acrylate, thereby introducing a substance with energy-curable groups on the polymer side chain via hydroxyl groups (copolymerization rate of monomers containing energy-curable groups: 23.4%, mass-average molecular weight (Mw): 715000, number-average molecular weight (Mn): 139000).

[0177] (A3) React 2-ethylhexyl acrylate resin (monomer mass ratio: 2-ethylhexyl acrylate / 2-hydroxyethyl acrylate = 80 / 20) with 2-isocyanate methyl methacrylate in an 80% equivalent amount relative to 2-hydroxyethyl acrylate, thereby introducing a substance with energy-curable groups on the polymer side chain via hydroxyl groups (copolymerization rate of monomers containing energy-curable groups: 22.7%, number average molecular weight (Mn): 86400).

[0178] <(B) Component: Crosslinking agent>

[0179] As a crosslinking agent, an isocyanurate-type polyisocyanate derived from hexamethylene diisocyanate is used.

[0180] (Examples 1-5)

[0181] An adhesive composition was prepared by dissolving the amounts of acrylate copolymer (A1) or (A2) and crosslinking agent (B) shown in Table 1 in toluene. The solid components of each material are shown in parts by weight in Table 1.

[0182] The adhesive composition was applied to the release surface of a release substrate (micro-embossed release sheet) with a concave shape. The resulting coating was dried at 100°C for 2 minutes, thereby forming an adhesive layer with a thickness of 25µm. The surface of the formed adhesive layer has a concave-convex shape similar to... Figure 2A The same shape features pillars arranged in a grid pattern. The spacing P between the pillars in the adhesive sheet is 20µm. Furthermore, as... Figure 4A As shown, the height (H) of each column is 8µm, the diameter at the front end (T) is 8µm, and the diameter at the base (W) is 16µm. It should be noted that, as the aforementioned release strip, a release strip with a concave shape on its surface that complements this uneven shape is used.

[0183] On the adhesive layer thus obtained, a substrate (ethylene-methacrylic acid copolymer (EMAA) film with an acid content of 9% by mass, one side of which is embossed to have a textured surface, a thickness of 80µm, and a tensile modulus of 160MPa) is bonded together to produce an adhesive sheet.

[0184] (Comparative Examples 1-2)

[0185] The amount of acrylate copolymer (A3) and crosslinking agent (B) shown in Table 1 was dissolved in toluene to prepare an adhesive composition. Otherwise, the adhesive composition was prepared in the same manner as in Example 1, and an adhesive sheet was made.

[0186] (Method for determining the elastic modulus of the adhesive layer)

[0187] The storage modulus and tanδ of the adhesive layers in each embodiment and comparative example were determined as follows. Specifically, the adhesive composition used in each embodiment was applied, and the resulting coating was dried at 100°C for 2 minutes to form an adhesive layer with a thickness of 25 µm. The adhesive layers thus formed were then stacked to a thickness of 1 mm. Then, an ultraviolet irradiation machine (Heraevier) was used with an irradiation of 130 mW / cm². 2 Light intensity 210 mJ / cm 2 The laminate was irradiated with ultraviolet light, thereby causing the energy-curable groups of the adhesive layer to crosslink. The resulting adhesive layer was then punched into a cylindrical shape with a diameter of 8 mm, thereby preparing a sample for dynamic viscoelasticity measurement.

[0188] The obtained samples were subjected to dynamic viscoelasticity determination using the torsional vibration method according to JIS K7244-7:2007. Specifically, a viscoelasticity measuring apparatus (manufactured by Rheometrics, named "DYNAMIC ANALYZERRDAII") was used, with vibrations of 10 Hz applied while the sample temperature was simultaneously increased from -30°C to 120°C. The storage modulus E' and loss modulus E'' at each temperature were then determined. The loss tangent tanδ at each temperature is represented by E'' / E'.

[0189] (Pick-up evaluation)

[0190] The pick-up performance of the objects held by the adhesive sheets obtained in each embodiment and comparative example was evaluated as follows. As shown below, silicon chips with a thickness of 150µm and 50µm were used as objects, respectively.

[0191] First, the adhesive sheets obtained in the various embodiments and comparative examples were adhered to an annular frame (made of stainless steel, with an inner diameter of 194 mm), and the adhesive sheets were cut to the corresponding outer diameter of the annular frame. Next, a wafer substrate (a polished silicon wafer, 6 inches, with a thickness of 150 µm or 50 µm) was fixed to a separately prepared dicing tape. Then, multiple components (silicon chips, with component sizes of 8 mm × 8 mm × 50 µm or 150 µm) were obtained by cutting the wafer substrate into 8 mm × 8 mm squares. The obtained components were adhered to the adhesive layer of the adhesive sheet in the central portion inside the annular frame, with the polished surface adhered to the uneven surface of the adhesive layer. Adhesion was completed by lamination at room temperature (23 °C). Then, the dicing tape was peeled off, thereby transferring the multiple components from the dicing tape to the adhesive sheet. Thus, as an evaluation sample, an adhesive sheet containing multiple components and supported by an annular frame was obtained.

[0192] The obtained evaluation samples were irradiated using an ultraviolet irradiation machine (Heraeste) at an illuminance of 130 mW / cm². 2 Light intensity 210 mJ / cm 2 Irradiation with ultraviolet light.

[0193] The evaluation sample, after UV irradiation, was placed in the pickup device (manufactured by Canon Machinery Co., Ltd., product name "BESTEM-D510"). After expanding the adhesive sheet, the element was picked up using a vacuum suction cup. It should be noted that the expansion of the adhesive sheet is as follows... Figures 5A-5BThe process is as shown. That is, with the component supported by the stage 310 via the adhesive sheet, the frame 320, which serves as a ring-shaped frame, is pulled down 10 mm towards the stage 310, thereby expanding the adhesive sheet. Furthermore, this evaluation assesses whether the component can be picked up from the side (substrate) opposite to the component to be adhered, without using the adhesive sheet. If the component can be picked up without damage, it is evaluated as "able to pick up" (A). If the component breaks during pickup, cannot be picked up, or fails to transfer from the wafer substrate to the adhesive sheet, it is evaluated as "unable to pick up" (F).

[0194] These evaluation results are shown in Table 1.

[0195] [Table 1]

[0196]

[0197] As shown in Table 1, fragile thin components with a thickness of 50µm can be picked up from the adhesive sheets of Examples 1-5 without the use of needles. Furthermore, it was confirmed that all components were transferred from the cutting tape to the adhesive sheets of Examples 1-5, and the adhesive sheets of Examples 1-5 possessed sufficient adhesive strength. In addition, components could not be picked up from the adhesive sheets of Comparative Examples 1-2 without breakage. This is believed to be because the adhesive sheets of Comparative Examples 1-2 also exhibited high adhesive strength after UV irradiation, thus requiring a large adsorption force for pickup.

[0198] As described above, it was confirmed that by using an adhesive layer with a value of (tanδ at 50°C) / (tanδ at 30°C) of 1.30 or higher, the adhesive force induced by ultraviolet radiation decreases, making it easier to pick up objects from the adhesive sheet. Furthermore, it was confirmed that by using an adhesive layer whose tanδ rise stops at a temperature greater than 55°C when heated from 0°C (tanδ rise termination temperature in Table 1), it becomes easier to pick up objects from the adhesive sheet.

[0199] The invention is not limited to the above-described embodiments, and various modifications and alterations can be made within the scope of the inventive intent.

[0200] This application claims priority based on Japanese Patent Application No. 2024-046979, No. 2024-046980, No. 2024-046981, No. 2024-046982, No. 2024-170363, and No. 2024-170369, filed on March 22, 2024, and the entire contents of which are incorporated herein by reference.

Claims

1. An adhesive sheet, the adhesive sheet comprising a substrate and an adhesive layer having an uneven surface, The adhesive layer is reactive to energy rays, and The value of the adhesive layer after irradiation by energy rays is greater than 1.30 (the loss tangent at 50°C, i.e., tanδ) / (tanδ at 30°C).

2. The adhesive sheet according to claim 1, wherein, In the adhesive layer after irradiation by energy rays, the temperature at which the increase of tanδ stops when heated from 0°C is greater than 55°C.

3. The adhesive sheet according to claim 1, wherein, The adhesive layer contains an acrylate copolymer with energy-curable groups.

4. The adhesive sheet according to claim 3, wherein, The acrylate copolymer has a monomer containing an energy-curable group as a (meth)acrylate monomer, and a (meth)acrylate monomer crosslinked with other (meth)acrylate monomers.

5. The adhesive sheet according to claim 1, wherein, The adhesive sheet can expand along the surface direction.

6. The adhesive sheet according to claim 1, wherein, The adhesive layer has protrusions with a height of 1µm or more.

7. The adhesive sheet according to claim 1, wherein, The adhesive layer has a plurality of protrusions, the plurality of protrusions being defined by recesses and separated from each other, and the spacing between the plurality of protrusions being greater than 1µm and less than 100µm.

8. The adhesive sheet according to claim 1, wherein, The adhesive layer has multiple protrusions, and the height of the multiple protrusions is uniform.

9. The adhesive sheet according to claim 1, wherein, It also has a release layer with a surface that is complementary to the surface of the adhesive layer.

10. A peeling method, the peeling method being a method of peeling an object from an adhesive sheet, the adhesive sheet being an adhesive sheet for holding the object in an adhesive layer according to any one of claims 1 to 9, the peeling method comprising: The irradiation process involves irradiating the adhesive layer with energy rays. The extension process involves extending the adhesive sheet along its surface direction. and The peeling process involves peeling the object off the adhesive layer of the adhesive sheet.

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