Method for peeling an object from an adhesive sheet and method for manufacturing an article

Abstract

The present application enables picking up an object held on an adhesive sheet having an adhesive layer with a surface having unevenness with a milder operation. A method of peeling an object from an adhesive sheet having a substrate and an energy-reactive adhesive layer with a surface having unevenness, and an object held on the adhesive layer. Energy is imparted to the adhesive sheet. The adhesive sheet is extended in a plane direction. After the energy imparting and the extension in the plane direction are performed, the object is peeled from the adhesive layer of the adhesive sheet.

Description

Technical Field

[0001] This invention relates to a method for peeling an object from an adhesive sheet and a method for manufacturing an article. Background Technology

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

[0003] On the other hand, in order to improve production efficiency, it is also required that the object be easily peeled off from the adhesive film. For example, Patent Document 1 discloses a configuration in which, with the electronic component adhered to a smooth first adhesive film, the adhesive force of the film is reduced by irradiating the film with ultraviolet light. 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.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-61529 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] The inventors of this application have studied the creation of uneven surfaces on the adhesive layer of an adhesive sheet. This configuration reduces the holding force of the sheet on the object, making it easier to pick up the object from the sheet for transfer printing. On the other hand, to minimize damage to the object during pickup, a gentler handling technique is required.

[0009] One embodiment of the invention enables the picking up of objects held on an adhesive sheet having an adhesive layer with an uneven surface with gentler operation.

[0010] Solution for solving the problem

[0011] Through repeated and in-depth research, the inventors discovered that when an object is peeled off from the adhesive layer of the adhesive sheet, by applying energy to the adhesive layer and expanding the adhesive sheet in the planar direction, the adhesive force of the adhesive layer is reduced, thereby making it easier to pick up the object. This solves the aforementioned technical problem. After further repeated research, the inventors completed this invention.

[0012] That is, the embodiments of the present invention relate to the following [1] to

[14] .

[0013] [1] A peeling method for peeling an object from an adhesive sheet having a substrate and an energy-reactive adhesive layer having an uneven surface, and holding the object in the adhesive layer, the peeling method comprising: a processing step of applying energy to the adhesive sheet; an expansion step of expanding the adhesive sheet in a planar direction; and a peeling step of peeling the object from the adhesive layer of the adhesive sheet after applying the energy and expanding in the planar direction.

[0014] [2] According to the peeling method described in [1], wherein the adhesive layer is energy ray reactive, and in the processing step, the adhesive sheet is irradiated with energy rays.

[0015] [3] According to the peeling method described in [2], in the processing step, the energy rays are irradiated in an amount that reduces the adhesive force of the adhesive layer to less than 70 mN / 25 mm.

[0016] [4] The peeling method according to any one of [1] to [3], wherein the thickness of the object is less than 50 μm.

[0017] [5] The peeling method according to any one of [1] to [4], wherein, in the expansion step, the adhesive sheet is expanded by more than 1% in the surface direction.

[0018] [6] According to any one of [1] to [5], the content of the polymer having energy-curable groups is 70 to 100 by mass relative to the total amount of the components constituting the adhesive layer.

[0019] [7] The peeling method according to any one of [1] to [6], wherein the adhesive layer has an acrylic resin having energy-curable groups and is crosslinked by an isocyanate-based crosslinking agent.

[0020] [8] The peeling method according to any one of [1] to [7], wherein the tensile modulus of the substrate is 2500 MPa or less.

[0021] [9] The peeling method according to any one of [1] to [8], 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.

[0022]

[10] The peeling method according to any one of [1] to [9], wherein the adhesive layer has a plurality of protrusions and the height of the plurality of protrusions is uniform.

[0023]

[11] The peeling method according to any one of [1] to

[10] , wherein, in the peeling step, an adsorption member is used to peel the object from the adhesive layer of the adhesive sheet.

[0024]

[12] According to the peeling method of

[11] , in the peeling process, the object is peeled from the adhesive layer of the adhesive sheet without applying physical stimulation from the opposite side of the adhesive layer of the adhesive sheet.

[0025]

[13] The peeling method according to any one of

[11] or

[12] , wherein, in the peeling process, the object is peeled from the adhesive layer of the adhesive sheet while applying physical stimulation from the opposite side of the adhesive layer of the adhesive sheet.

[0026]

[14] A method for manufacturing an article, the method comprising: a step of peeling the object from the adhesive sheet according to any one of [1] to

[13] ; and a step of manufacturing the article by post-processing the object.

[0027] Invention Effects

[0028] One embodiment of the invention enables the picking up of objects held on an adhesive sheet having an adhesive layer with an uneven surface with gentler operation.

[0029] Other features and advantages of the present 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

[0030] The accompanying drawings, which are included in and form a part of this specification, illustrate embodiments of the invention and, together with the description therein, serve to explain the principles of the invention.

[0031] Figure 1 This is a cross-sectional view of an adhesive sheet according to one embodiment.

[0032] Figure 2A This is a cross-sectional view showing an example of the unevenness of the adhesive layer before expansion.

[0033] Figure 2B This is a cross-sectional view showing an example of the unevenness of the adhesive layer after expansion.

[0034] Figure 3A This is a top view showing an example of the unevenness of the adhesive layer before expansion.

[0035] Figure 3B This is a top view showing an example of the unevenness of the adhesive layer after expansion.

[0036] Figure 3C This is a top view showing another example of the unevenness of the adhesive layer.

[0037] Figure 4A This is a cross-sectional view showing an example of the unevenness of the adhesive layer.

[0038] Figure 4B This is a cross-sectional view showing an example of the unevenness of the adhesive layer.

[0039] Figure 4C This is a cross-sectional view showing an example of the unevenness of the adhesive layer.

[0040] Figure 5A This is a diagram illustrating the method of spreading adhesive sheets.

[0041] Figure 5B This is a diagram illustrating the method of spreading adhesive sheets.

[0042] Figure 6 This is a flowchart of a method for manufacturing an adhesive sheet according to one embodiment.

[0043] Figure 7 This is a flowchart of a stripping method for one implementation. Detailed Implementation

[0044] 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.

[0045] (definition)

[0046] In this specification, the mass-average molecular weight (Mw) and number-average molecular weight (Mn) are values ​​converted from standard polystyrene determined by size exclusion chromatography, specifically 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.

[0047] 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 statement "preferably 1 or more, more preferably 2 or more, further preferably 3 or more, preferably 9 or less, more preferably 8 or less, further preferably 7 or less" clearly means that the numerical range can be any range among 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 refer to the proportion based on the mass of the solid component.

[0048] (Composition of adhesive sheet)

[0049] 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 on 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, reference will be made to a schematic diagram of an adhesive sheet as one embodiment. Figure 1 Explain the composition of such an adhesive sheet.

[0050] (Substrate)

[0051] The substrate 120 functions as a support for the adhesive layer 110. The substrate 120 is located on the opposite side of the surface of the adhesive layer 110 that has uneven surfaces.

[0052] In one embodiment, the adhesive sheet is capable of extending in the planar direction. From this perspective, a flexible substrate can be used as the substrate 120. Furthermore, by using a flexible substrate as the substrate 120, the cushioning when holding an object can be improved, making the lamination of the adhesive sheet easier, or allowing 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 composed of resin material or may contain additives in addition to the resin material. The resin film can be laser-transmissive.

[0053] 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.

[0054] From the viewpoint of facilitating the expansion of the adhesive sheet, the substrate 120 is preferably a polyolefin-based film or a vinyl chloride copolymer film. Examples of polyolefin-based 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 such copolymers is not particularly limited and can be any of block copolymers, random copolymers, alternating copolymers, and graft copolymers. It should be noted that these films may also contain other resin components or additives.

[0055] The thickness of the substrate 120 is not particularly limited, but from the viewpoint of balancing support and winding properties, it is preferably 10 μm or more, more preferably 25 μm or more, and even more preferably 40 μm or more. On the other hand, it is preferably 500 μm or less, more preferably 200 μm or less, even more preferably 150 μm or less, even more preferably 150 μm or less, even more preferably 120 μm or less, and particularly preferably 90 μm or less.

[0056] 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.

[0057] 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.

[0058] (Adhesive layer)

[0059] 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 also have two or more adhesive layers 110. For example, the adhesive sheet may be a laminate of one or more adhesive layers 110.

[0060] In one embodiment, the adhesive layer 110 is energy-reactive. In this specification, energy reactivity refers to an increase in the elastic modulus by imparting energy. For example, the adhesive layer 110 may be energy-ray reactive or thermally reactive. The type of energy ray is not particularly limited; examples include ultraviolet light, electron beams, or ionizing radiation. Ultraviolet light is preferred as the energy ray; that is, the adhesive layer 110 preferably has ultraviolet reactivity.

[0061] The composition of adhesive layer 110 will now be described as an example. However, the composition of adhesive layer 110 is not limited to the example shown below.

[0062] (Resin)

[0063] 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-based resins such as polyisobutylene resins, polybutadiene resins, and styrene-butadiene resins, acrylic resins, polyurethane 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.

[0064] The resin included 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 below a predetermined value, it is preferably 2,000,000 or less, 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 below a predetermined value, it is preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,200,000 or less. It should be noted that, as described later, when the adhesive layer 110 includes a resin derived from an energy-reactive resin, the mass-average molecular weight (Mw) and number-average molecular weight (Mn) refer to the mass-average molecular weight (Mw) and number-average molecular weight (Mn) before the crosslinking reaction caused by energy impartation.

[0065] 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. In this case, the Tg of the monomer used to derive the structural unit can be the value recorded in a polymer datasheet or adhesive manual.

[0066] 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. However, it is preferably 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, and even more preferably 99.50% by mass or less.

[0067] From the viewpoint of morphological stability of the unevenness of the adhesive layer surface, the storage modulus of the adhesive layer 110 is preferably 0.001 MPa or more, more preferably 0.01 MPa or more, even more preferably 0.03 MPa or more, and even more preferably 0.07 MPa or more. On the other hand, a low storage modulus of the adhesive layer 110 is preferable in that it can suppress positional displacement when holding the object. From this viewpoint, the storage modulus of the adhesive layer 110 is preferably 100 MPa or less, more preferably 50 MPa or less, even more preferably 20 MPa or less, and particularly preferably 5 MPa or less. In this specification, the storage modulus is measured according to JIS K7244-1:1998. Specifically, a cylindrical sample with a thickness of 3 mm and a diameter of 8 mm can be prepared, and the storage modulus of the sample can be measured by torsional shear method at 1 Hz and 23 °C using a viscoelastic measuring device, thereby determining the storage modulus of the adhesive layer 110.

[0068] In one embodiment, the resin contained in the adhesive layer 110 may include a thermoplastic resin. That is, the adhesive layer 110 may be formed of a thermoplastic resin. When using a thermoplastic resin, heating softens the resin, making it easy to form unevenness in the adhesive layer 110, and cooling easily maintains the formed uneven shape. Examples of thermoplastic resins include rubber-based resins, acrylic resins, urethane resins, and olefin-based resins. Examples include polybutadiene-based thermoplastic elastomers using butadiene as a monomer, styrene-based thermoplastic elastomers using styrene as a monomer, and acrylic thermoplastic elastomers using (meth)acrylic acid or (meth)acrylate as monomers.

[0069] (Energy-reactive components)

[0070] As described above, the adhesive layer 110 can be energy-reactive. Therefore, the adhesive layer 110 can contain an energy-reactive component. The energy-reactive component can be a compound incorporating polymerizable functional groups. Polymerizable functional groups are functional groups that crosslink by imparting energy. 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 groups. The crosslinking of such polymerizable functional groups occurs in the presence of a suitable polymerization initiator or crosslinking agent.

[0071] The energy-reactive component can be a difunctional or polyfunctional monomer that incorporates 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.

[0072] (Energy-reactive resin (A))

[0073] In one embodiment, the resin contained in the adhesive layer 110 is energy-reactive. That is, as described above, the adhesive layer 110 may contain an energy-reactive resin. Examples of energy-reactive resins include energy-ray-reactive resins and heat-reactive resins. The energy-reactive resin may be an energy-ray-curable resin. Furthermore, the heat-reactive resin may be a thermosetting resin. It should be noted that, in this specification, an energy-reactive resin refers to a resin whose elastic modulus increases by applying energy. On the other hand, resins whose elastic modulus has already increased due to applying energy, and whose elastic modulus will not increase even if further energy is applied (e.g., UV-curable resins after curing) are not included in the energy-reactive resins of this specification.

[0074] Thus, by using an energy-reactive resin in the adhesive layer 110, the elastic modulus of the adhesive layer 110 is more easily increased when energy is applied. Furthermore, it is easier to simultaneously achieve both the holding force of the adhesive layer 110 on the object before energy is applied and the ease with which the object can be peeled off the adhesive layer 110 after energy is applied. Moreover, by using an energy-reactive resin in the adhesive layer 110, while improving the retention of the uneven shape of the adhesive layer 110, it is also easier to maintain a high adhesive force before energy is applied.

[0075] In one embodiment, the adhesive layer 110 comprises an energy-reactive resin, which is a polymer having energy-curable groups. This polymer may also be a copolymer. Furthermore, the polymer may 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. In one embodiment, the energy-curable group is an ultraviolet-curable group. When the adhesive layer 110 comprises a polymer with ultraviolet-curable groups, the energy-curable groups of the polymer can be cross-linked by irradiating the adhesive layer 110 with ultraviolet light.

[0076] 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, relative to the total amount of the components constituting the adhesive layer 110. On the other hand, it is 100% by mass or less, more preferably 99% by mass or more, and even more preferably 98% by mass or less.

[0077] The number of energy-ray-reactive groups in the energy-ray-reactive resin can be appropriately set according to the application of the adhesive sheet. In one embodiment, from the viewpoint of reducing the adhesive strength after curing, the proportion of structural units having energy-ray-reactive groups in the structural units constituting the polymer as an energy-ray-reactive resin is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more. Furthermore, from the viewpoint of maintaining the adhesiveness after curing, the proportion of structural units having energy-ray-reactive groups in the structural units constituting the polymer as an energy-ray-reactive resin is preferably 50 mol% or less, more preferably 40 mol% or less, and even more preferably 30 mol% or less.

[0078] On the other hand, as described above, the adhesive layer 110 has an uneven surface. Therefore, it is desirable that the adhesive layer 110 has an elastic force capable of maintaining the unevenness of the surface even before energy is applied. From this viewpoint, in one embodiment, the adhesive layer 110 has a cross-linked polymer. Furthermore, the main component of the adhesive layer 110 may also be a cross-linked polymer. For example, from the viewpoint of maintaining the unevenness of the surface, the content of the cross-linked polymer relative to the total amount of the components constituting the adhesive layer 110 is preferably 70% by mass or more, more preferably 80% by mass, further preferably 90% by mass or more, on the other hand, 100% by mass or less, more preferably 99% by mass or more, and further preferably 98% by mass or less. The type of cross-linking is not particularly limited. For example, functional groups such as hydroxyl, vinyl, (meth)acryloyl, amino, carboxyl, or isocyanate groups present in the polymer can be cross-linked via a cross-linking agent (B) described later, or can be cross-linked directly without cross-linking agent (B). For example, the polymer may have urethane cross-linking. Urethane cross-linking refers to cross-linking via urethane bonds.

[0079] The crosslinked polymer in the adhesive layer 110 can also be a polymer having the aforementioned energy-curable groups. That is, the polymer in the adhesive layer 110 having energy-curable groups can be crosslinked. For example, the polymer having energy-curable groups can have both side chains with energy-curable groups and crosslinked side chains. Such a polymer can be manufactured, for example, by preparing a polymer with side chains having energy-curable groups and thermally reactive side chains, and using a crosslinking agent to crosslink the thermally reactive side chains. The specific crosslinking method is not particularly limited. For example, isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, or metal chelate-based crosslinking agents can be used as crosslinking agents. Specifically, the thermally reactive side chains can have hydroxyl groups; in such cases, by using an isocyanate-based crosslinking agent, the thermally reactive side chains can be crosslinked to form urethane crosslinks.

[0080] The number of crosslinks in the energy-ray reactive resin can be appropriately set according to the application of the adhesive sheet. In one embodiment, from the viewpoint of maintaining the surface texture, the proportion of crosslinked structural units in the structural units constituting the polymer as an energy-ray reactive resin is preferably 0.5 mol% or more, more preferably 1 mol% or more, and even more preferably 1.5 mol% or more. Furthermore, from the viewpoint of improving adhesion, the proportion of structural units having energy-ray curable groups in the structural units constituting the polymer as an energy-ray reactive resin is preferably 20 mol% or less, more preferably 10 mol% or less, and even more preferably 5 mol% or less.

[0081] As a more specific example, a polymer having energy-curable groups can be manufactured by modifying a polymer (including copolymers) having a first type of structural unit. This first type of structural unit of the polymer, for example, has hydroxyl groups. Then, in the polymer having energy-curable groups, a portion of the hydroxyl groups of the first type of structural unit is modified to have a carbon-carbon double bond via a urethane bond. Furthermore, another portion of the hydroxyl groups of the first type of structural unit is modified to form urethane crosslinks.

[0082] Such polymers can be prepared, for example, by the following method. First, a compound containing carbon-carbon double bonds and having isocyanate groups can be used to modify a portion of the hydroxyl groups of the first type of structural unit, in an amount less than the hydroxyl groups of the first type of structural unit of the polymer. Furthermore, an isocyanate-based crosslinking agent, such as a polyisocyanate compound, can be used to crosslink the hydroxyl groups of the other portion of the first type of structural unit with each other using urethane. In this case, from the viewpoint of maintaining the surface texture while reducing the adhesion after curing, the amount of the compound containing carbon-carbon double bonds and having isocyanate groups used relative to the hydroxyl groups of the first type of structural unit of the polymer is preferably 25% equivalent or more, more preferably 50% equivalent or more, further preferably 80% equivalent or more, and on the other hand, preferably 99% equivalent or less, more preferably 98% equivalent or less, and further preferably 95% equivalent or less. In addition, the amount of the isocyanate-based crosslinking agent used may also be excessive relative to the hydroxyl groups of the first type of structural unit of the polymer.

[0083] (Acrylic resin with energy beam curing properties)

[0084] In one embodiment, the polymer of the adhesive layer 110 is an acrylic resin. The adhesive layer 110 may contain an acrylic resin as an energy-reactive resin. The acrylic resin is a resin containing (meth)acrylic acid or (meth)acrylate as monomers.

[0085] Examples of (meth)acrylates constituting acrylic resins 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... Alkyl methacrylates with a chain structure having 1 to 18 carbon atoms; cycloalkyl methacrylates such as isobornyl 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 an amino group are replaced by a group other than hydrogen atoms.

[0086] Acrylic resins can be, for example, resins obtained by copolymerizing one or more monomers selected from itaconic acid, vinyl acetate, acrylonitrile, styrene, and N-hydroxymethylacrylamide, in addition to (meth)acrylate or (meth)acrylic acid.

[0087] Acrylic resins can be homopolymers or copolymers. That is, the monomers constituting acrylic resins can be only one type or two or more types. In the case of two or more types, their combination and ratio can be arbitrarily chosen.

[0088] As described above, acrylic resins can be energy-reactive. For example, acrylic resins can have energy-curable groups. Specifically, acrylic resins can have side chains with energy-curable groups. Such acrylic resins can be obtained by polymerization using monomers with energy-curable groups. Furthermore, such acrylic resins can be obtained by modifying the polymer to introduce energy-curable groups. For example, acrylic resins can contain hydroxyl-containing (meth)acrylates as structural units. Energy-curable groups can be introduced by reacting the hydroxyl groups of such acrylic resins with compounds such as ethyl 2-isocyanate methacrylate, which have isocyanate groups and energy-curable groups.

[0089] Furthermore, as described above, the acrylic resin can also be a cross-linked polymer. For example, the acrylic resin can be cross-linked by an isocyanate-based cross-linking agent. Such an acrylic resin can be obtained through a cross-linking reaction of the polymer. As described above, the acrylic resin can contain hydroxyl-containing (meth)acrylates as structural units. By reacting such an acrylic resin with an isocyanate-based cross-linking agent such as a polyisocyanate compound, the hydroxyl groups of the acrylic resin can be cross-linked with each other to form urethane. The amount of the isocyanate-based cross-linking agent used is not particularly limited; for example, an excess of cross-linking agent can be used relative to the hydroxyl groups of the acrylic resin. In one embodiment, from the viewpoint of maintaining the unevenness of the surface of the adhesive layer 110, the amount of the isocyanate-based cross-linking agent is preferably 1.5 parts by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, relative to 100 parts by mass of the polymer. From the viewpoint of improving the holding power of the adhesive layer 110 to the object, the amount of the isocyanate-based cross-linking agent 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, relative to 100 parts by mass of the polymer.

[0090] As described above, the adhesive layer 110 may be an acrylic resin having energy-curable groups and crosslinked by an isocyanate-based crosslinking agent. One embodiment of the acrylic resin comprises hydroxyl-containing (meth)acrylates as structural units, a portion of which has hydroxyl groups modified to have carbon-carbon double bonds via urethane bonds. Furthermore, another portion of which has hydroxyl groups is modified to form urethane crosslinks.

[0091] (Other components of the adhesive layer)

[0092] The adhesive layer 110 may contain components other than resin. For example, the adhesive layer 110 may contain one or more of a crosslinking agent (B), a photopolymerization initiator (C), an antioxidant, and other additives.

[0093] Examples of crosslinking agents (B) include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, and metal chelate-based 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 of the resin contained in the adhesive layer 110. For example, the crosslinking agent can also be a crosslinking agent of acrylic resin.

[0094] Among these crosslinking agents, isocyanate-based crosslinking agents are preferred from the viewpoints of improving cohesive strength to maintain the uneven shape and being readily available. Examples of isocyanate-based crosslinking agents include aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and phenyldimethyl diisocyanate; alicyclic polyisocyanates such as dicyclohexylmethane-4,4'-diisocyanate, dicycloheptan triisocyanate, cyclopentyl diisocyanate, cyclohexyl diisocyanate, methylcyclohexyl diisocyanate, methylene bis(cyclohexyl isocyanate), 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, and hydrogenated phenyldimethyl diisocyanate; noncyclic aliphatic polyisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate; and other polyisocyanate compounds. In addition, as isocyanate-based crosslinking agents, examples include trimethylolpropane adduct-type modifiers of the polyisocyanate compound, biuret-type modifiers formed by reaction with water, and isocyanurate-type modifiers containing isocyanurate rings.

[0095] The adhesive layer 110 may contain one crosslinking agent or two or more crosslinking agents. From the viewpoint of suitable 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. Here, the content of the crosslinking agent in the adhesive layer 110 includes not only the amount of unreacted crosslinking agent but also the amount of crosslinking agent that forms crosslinks.

[0096] The photopolymerization initiator (C) initiates a crosslinking reaction in response to the application of energy (e.g., irradiation by an energy ray such as ultraviolet light). When the adhesive layer 110 contains an energy-reactive resin (A), the crosslinking reaction proceeds even with a relatively low energy application by further including the photopolymerization initiator (C) in the adhesive layer 110.

[0097] Examples of photopolymerization initiators (C) 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.

[0098] 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.

[0099] Examples of antioxidants include hindered phenolic compounds, aromatic amine compounds, sulfur compounds, and phosphorus compounds such as phosphate esters.

[0100] Other additives that may be included in the adhesive layer 110 are not particularly limited, such as ultraviolet 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.

[0101] 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.

[0102] (Shape of the adhesive layer)

[0103] 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. Each of the plurality of protrusions can be separated by recesses that are continuous throughout the adhesive layer 110.

[0104] 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 2Band Figure 3B An example of the expanded adhesive layer 110 is shown. Furthermore, in Figures 2A-2B The image depicts an object 140 held by the protrusions 111 of the adhesive layer 110; on the other hand, in Figures 3A-3C In the text, the object 140 held by the protrusion 111 is omitted.

[0105] like Figure 2A and Figure 3A As shown, protrusions 111 can be regularly arranged on the surface of the adhesive layer 110. Regular arrangement of the protrusions means that they are arranged in a straight line at regular intervals. Alternatively, the protrusions 111 can be arranged with varying intervals. For example, the intervals between protrusions in the center of the adhesive sheet can be short, while the intervals between protrusions in the periphery of the adhesive sheet can be long. Furthermore, the protrusions can also be irregularly arranged.

[0106] Figure 3C This is a top view showing another shape of the adhesive layer 110. (See attached image.) Figure 3C As shown, striped 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.

[0107] From the viewpoint of adjusting the holding force, the spacing P of the protrusions 111 before expansion is preferably 1 μm or more, more preferably 5 μm or more, further preferably 10 μm or more, and even more preferably 15 μm 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 100 μm or less, more preferably 75 μm or less, even more preferably 50 μm or less, even more preferably 35 μm or less, and even more preferably 25 μm or less. Here, the spacing P of the protrusions 111 means the distance between the center point of any chosen protrusion 111 and the center point of the nearest other 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 nearest other 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 means the interval between the centers of the protrusions.

[0108] 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 an inverted taper.

[0109] Figure 4A A cross-sectional view of an adhesive layer 110 according to one embodiment is shown, perpendicular to the surface of the adhesive layer 110 through the protrusion 111. 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.

[0110] 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 protrusions 111 of the adhesive layer 110, which are separated from each other, can be defined by the recesses.

[0111] As another example, a protrusion can be like... Figure 4B As shown, it is hemispherical or part of a sphere. Furthermore, the protrusion 111 can be as follows: Figure 4C As shown, it is T-shaped. As further examples, the protrusion 111 can be in the shape of multiple particles aggregated, mushroom-shaped, lotus leaf-like, or needle-shaped. As further examples, the surface of the adhesive layer 110 can be rough or fibrous, such a surface may also be described as having irregularities.

[0112] From the viewpoint of maintaining the holding force of the object, the width or diameter of each protrusion 111 is preferably 1 μm or more, more preferably 2 μm or more, further preferably 5 μm or more, and even more preferably 10 μm or more. On the other hand, from the viewpoint of improving the ease of peeling off the object, it is preferably 100 μm or less, more preferably 50 μm or less, even more preferably 30 μm or less, and even more preferably 20 μm or less. Here, the width and diameter of the protrusion 111 refer to the minimum distance and maximum distance (in the case of the concave surface) between two parallel lines tangent to both sides of the protrusion 111. Figure 4A (represented by W in Chinese).

[0113] Furthermore, regarding the area of ​​each protrusion 111, from the viewpoint of maintaining the holding force of the object, it is preferably 10 μm. 2 The above, more preferably 20μm2 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, 2000 μm is preferred. 2 Below, 1000 μm is more preferred. 2 Hereinafter, 500 μm is further preferred. 2 Below. Here, the area of ​​the protrusion 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...

[0114] In one embodiment, from the viewpoint of improving the ease of peeling off the object, the height of each protrusion 111 is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm 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 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. This allows for a change in the holding force of the object. Here, the height of the protrusion 111 is... Figure 4A The protrusions are denoted by H. Furthermore, in one embodiment, the height of the plurality of protrusions in the adhesive layer 110 is uniform. 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 a first protrusion and a second protrusion. In a further embodiment, the adhesive layer 110 may have a plurality of protrusions with random heights.

[0115] 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.

[0116] (Characteristics of the adhesive layer)

[0117] As described above, in one embodiment, the adhesive layer 110 is energy-reactive. Therefore, by applying energy to the adhesive layer 110 (e.g., by irradiating it with energy rays), the elastic modulus of the adhesive layer 110 increases. Furthermore, by applying energy to the adhesive layer 110, the adhesive force of the adhesive layer 110 decreases.

[0118] In one embodiment, from the viewpoint of improving the retention force of the object, the adhesive force of the adhesive layer before being energized (e.g., before irradiation by energy rays) is preferably 2000 mN / 25 mm or more, more preferably 2200 mN / 25 mm or more, and even more preferably 2500 mN / 25 mm or more; on the other hand, it may be 6000 mN / 25 mm or less. Furthermore, from the viewpoint of making the object easier to peel off, the adhesive force of the adhesive layer after being energized (e.g., after irradiation by energy rays) is preferably 100 mN / 25 mm or less, more preferably 70 mN / 25 mm or less, and even more preferably 50 mN / 25 mm or less; on the other hand, it may be 25 mN / 25 mm or more.

[0119] It should be noted that the adhesive strength of the adhesive layer 110 can be measured using a tensile testing machine at 23°C and 50% RH (relative humidity) according to JIS Z0237:2000. This adhesive strength can be adjusted by controlling the composition of the adhesive layer 110. For example, by increasing the amount of crosslinking agent (B) used in the adhesive layer 110, a tendency to decrease the adhesive strength before and after energy application can be observed. Furthermore, to reduce the adhesive strength after energy application, the number of energy-curable groups contained in the adhesive layer 110 can be increased.

[0120] Furthermore, in one embodiment, from the viewpoint of easily picking up the object from the adhesive sheet, when the adhesive sheet is attached to the object, the proportion of the area of ​​the adhesive sheet attached to the object is preferably 60% or less, more preferably 30% or less, even more preferably 15% or less, and particularly preferably 10% or less. Furthermore, from the viewpoint of improving the object's holding power, this proportion of the attached area is preferably 4% or more, even more preferably 5% or more.

[0121] The attachment area ratio refers to the ratio of the area of ​​the contact surface between the adhesive sheet and the object to the area of ​​the adhesive sheet. This attachment area ratio can be calculated as follows: after pressing the adhesive sheet onto a silicon wafer using a laminator and allowing it to stand for 10 minutes, the resulting sample is observed under a microscope to evaluate the area of ​​the contact surface between the adhesive sheet and the silicon wafer, and the ratio is calculated based on this area. This attachment area ratio is a value evaluated before applying energy to the adhesive layer 110. This attachment area ratio can be adjusted by controlling the composition of the adhesive layer 110. For example, by increasing the amount of crosslinking agent (B) used in the adhesive layer 110, a tendency to decrease the attachment area ratio can be observed. Furthermore, to reduce the attachment area ratio, a resin with a lower elastic modulus can be used as the material for the adhesive layer 110.

[0122] Furthermore, in one embodiment, from the viewpoint of easily maintaining the uneven shape of the adhesive layer 110, the gel fraction of the adhesive layer 110 is preferably 90% or more, more preferably 92% or more, and even more preferably 94% or more. Moreover, the gel fraction of the adhesive layer 110 is 100% or less; from the viewpoint of improving the holding power of the object, it is preferably 98% or less, more preferably 96% or less. This gel fraction refers to a value evaluated before energy is imparted to the adhesive layer 110.

[0123] The gel fraction is evaluated based on the mass before and after solvent impregnation and drying treatments. Specifically, the gel fraction represents the ratio of the mass after treatment to the mass before treatment. In the impregnation treatment, the test sample was impregnated in toluene at room temperature (23°C) for 168 hours. Furthermore, in the drying treatment, drying was performed at 100°C for 2 hours. Such a gel fraction can be adjusted by controlling the composition of the adhesive layer 110. For example, by increasing the amount of crosslinking agent (B) used in the adhesive layer 110, a tendency to increase the gel fraction can be observed.

[0124] Furthermore, the adhesive sheet in one embodiment can be extended in 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', in adhesive layer 110', the spacing P of each protrusion 111 increases due to expansion, and the number of protrusions 111 holding one object 140 decreases. As a result, in adhesive layer 110', the force used to hold the object 140 by the protrusions 111 is reduced compared to adhesive layer 110. Furthermore, due to the expansion of the adhesive sheet, shear stress acts between the protrusions 111 and the object 140. The inventors of this application have observed that this is also related to the 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% or more in the planar direction (e.g., one direction or two orthogonal directions), or by more than 5%.

[0125] (Peeling layer)

[0126] Furthermore, the adhesive sheet of this embodiment is as follows: Figure 1 As shown, a release tab 150 may be present 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.

[0127] The release tab 150 has a release layer 160. The release layer 160 is a layer that is easily peeled off 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, it is not necessary for the recess 161 to have a shape complementary to the convex portion 111.

[0128] 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 need not 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.

[0129] (Other layers)

[0130] The sheet described above may have layers other than the substrate 120 and the adhesive layer 110. For example, a further adhesive layer may be provided on the surface of the substrate 120 opposite to the adhesive layer 110. The sheet can be attached to other objects via such an adhesive layer. The type of the further adhesive layer is not particularly limited; for example, a general adhesive can be used to form the further adhesive layer.

[0131] (Manufacturing method of adhesive sheet)

[0132] There are no particular limitations on the manufacturing method of the adhesive sheet and adhesive layer 110. See below for reference. Figure 6 This is an example illustrating the manufacturing method of adhesive sheets.

[0133] In S610, a material layer comprising the material of the adhesive layer 110 is formed on the substrate 120. First, an adhesive composition is prepared by adding an organic solvent to a raw material composition comprising the components of the adhesive layer 110. Then, the solution is coated onto the substrate 120 to form a film, and then dried, thereby forming a material layer on the substrate 120.

[0134] When forming an adhesive layer 110 comprising a polymer having energy-curable groups, the adhesive composition may comprise the polymer having energy-curable groups. In this case, a material layer comprising the polymer having energy-curable groups is formed. Furthermore, when the adhesive layer 110 comprises a crosslinked polymer (e.g., a crosslinked polymer having energy-curable groups), the adhesive composition may comprise the uncrosslinked polymer. Moreover, the adhesive composition may comprise a crosslinking agent. In this case, a material layer comprising the uncrosslinked polymer and the crosslinking agent is formed.

[0135] 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).

[0136] In S620, unevenness is formed on the surface of the material layer thus formed. There are no particular limitations on the process of creating unevenness on the surface of the material layer. For example, an embossing method can be used to create unevenness on the surface of the material layer. In the embossing method, a mold having uneven surfaces complementary to the unevenness to be created can be used. Thus, an adhesive layer 110 with unevenness is formed. Specifically, the material layer can be pressed with a mold, heated and maintained for a predetermined time, then the material layer can be cooled and the mold removed. When heating the material layer, for example, the material layer can be heated to a temperature higher than the softening point of the material layer. As a specific method for pressing the material layer with a mold while heating the material layer, a method of vacuum laminating the material layer disposed 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 as described above can be used.

[0137] On the other hand, to improve the maintenance of the uneven shape, energy can be applied to the material layer when the unevenness is formed on the surface of the material layer. By applying energy to cause the curing reaction in the material layer, the elastic modulus of the adhesive layer 110 can be increased, thus improving the maintenance of the uneven shape. Specifically, the material layer can be thermo-cured while a mold having uneven surfaces complementary to the unevenness is in contact with the material layer, thereby forming an adhesive layer 110 with an uneven surface. In one embodiment, a crosslinking reaction is used as the curing reaction. As described above, when the material layer contains a polymer and a crosslinking agent before crosslinking, the material layer is heated while being pressed with a mold, thereby causing a crosslinking reaction and forming an adhesive layer 110 containing a crosslinked polymer. In particular, when the adhesive composition contains a polymer with energy-curable groups before crosslinking, unreacted energy-curable groups can remain in the adhesive layer 110 by using a heated crosslinking reaction.

[0138] As another method, the adhesive layer 110 with a rough surface can be formed by spraying the adhesive composition. Alternatively, the adhesive layer 110 with a rough or fibrous surface can be formed by adding filler to the adhesive composition and applying such a solution. As a further alternative method, the adhesive composition can be applied to the substrate 120 according to a desired pattern using a printing method such as inkjet printing to directly form the adhesive layer 110 with an uneven shape.

[0139] (How to use adhesive sheets)

[0140] 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.

[0141] Regarding the method for processing objects using the adhesive sheet of this embodiment, please refer to... Figure 7 The flowchart is explained.

[0142] (S710: Object retention)

[0143] In S710, the adhesive layer of the adhesive sheet of this embodiment is held in place. 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 chip-on-a-flush (DAF). Furthermore, the component can be a miniature light-emitting diode, a power device, a MEMS (Micro Electro Mechanical Systems) chip, or a controller chip, or a component thereof. Additionally, 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 is formed, the integrated circuit having circuit objects such as transistors, resistors, and capacitors. Furthermore, the component is not necessarily limited to a monolithic assembly; it can also be various non-monolithic wafers or various substrates.

[0144] Furthermore, the size of the object is not particularly limited. 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.

[0145] 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.

[0146] 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; for example, it can be a rectangular substrate of approximately 300 to 700 mm.

[0147] Examples of substrates include glass substrates, sapphire substrates, and compound semiconductor substrates.

[0148] In one embodiment, a component is transferred from a holding substrate to an adhesive sheet, which holds the transferred component. For example, a semiconductor wafer can be attached to a wafer substrate and then diced. The component 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 component can be reduced. Through this process, the component can be transferred from the wafer substrate to the adhesive sheet. Alternatively, the component obtained by dicing a semiconductor wafer can be transferred to a holding substrate, thereby obtaining a holding substrate with the component attached. Then, the component attached to the holding substrate can be transferred to the adhesive layer 110 of the adhesive sheet using the same method.

[0149] In another embodiment, an external stimulus can be used to detach the component attached to the holding substrate from the holding substrate. Specifically, the component is relatively far away from the holding substrate, while relatively close to the adhesive sheet. Then, by contacting the component with the adhesive layer 110 of the adhesive sheet, the component is detached from the holding substrate and captured by the adhesive sheet. The type of external stimulus is not particularly limited, and examples include energy application, cooling, expansion of the holding substrate, and physical stimuli (e.g., pressing the back of the holding substrate using a pin). By using one or more of these external stimuli, the bonding force between the holding substrate and the component can be reduced, and the component can then be detached from the holding substrate. For example, the component can be detached from the holding substrate by laser irradiation (laser peeling). In such an embodiment, when the detached component approaches the adhesive layer 110, pressure is generated between the component and the adhesive layer 110. However, because the surface of the adhesive layer 110 has irregularities, the pressure generated between the component and the adhesive layer 110 is mitigated, making it easier to capture the component at the desired location on the adhesive sheet.

[0150] In a further embodiment, a semiconductor wafer is attached to the adhesive layer 110 of the adhesive sheet. Then, a device is formed by cutting the semiconductor wafer on the adhesive layer 110. In this way, the adhesive sheet can also hold the device.

[0151] (S720: Adhesion reduction treatment)

[0152] In S720, the adhesive force of the adhesive layer 110 holding the object is reduced. To reduce the adhesive force, one or both of the following steps can be performed: a processing step that applies energy to the adhesive sheet, and an expansion step that expands the adhesive sheet in the planar direction. By applying energy to the energy-responsive adhesive layer 110, the elastic modulus of the adhesive layer 110 increases, and the adhesive force decreases. Furthermore, by expanding the adhesive sheet in the planar direction, as described above, the holding force of the adhesive layer 110 on the object is reduced.

[0153] During the processing steps, energy corresponding to the type of adhesive layer 110 can be imparted. For example, if the adhesive layer 110 is energy-reactive, energy rays can be irradiated onto the adhesive sheet during the processing steps.

[0154] The amount of energy applied during the processing can be set according to the type of adhesive layer 110 and the desired adhesive strength. For example, when irradiating with ultraviolet light, from the viewpoint of sufficiently reducing adhesive strength, the intensity of the ultraviolet light is preferably 20 mJ / cm. 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.

[0155] Furthermore, during the processing step, energy rays of an amount that reduce the adhesive force of the adhesive layer 110 can be irradiated. For example, from the viewpoint of making the object easier to peel off, energy rays of an amount that reduces the adhesive force of the adhesive layer 110 to preferably 100 mN / 25 mm or less, more preferably 70 mN / 25 mm or less, and even more preferably 50 mN / 25 mm or less can be irradiated. Moreover, during the processing step, energy rays of an amount that increases the elastic modulus of the adhesive layer 110 can be irradiated.

[0156] In the expansion process, the adhesive sheet expands in the planar direction. The method of expanding the adhesive sheet is not particularly limited. For example, the expansion of the adhesive sheet can be performed in one direction, two directions, or even multiple directions. The expansion rate of the adhesive sheet is also not particularly limited. 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 breakage of the adhesive sheet, 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.

[0157] As a specific example, the adhesive sheet can be expanded by fixing it to the frame and pressing the base onto the adhesive sheet inside the frame. For such an example, see [link to relevant documentation]. Figures 5A-5B Please provide an explanation. Figure 5A This shows the state in which the adhesive sheet holds the object 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 expanded in all directions.

[0158] Then, the adhesive sheet fixed to the frame 320 is brought into contact with the base 310, and then... Figure 5B As shown, the adhesive sheet can be expanded by displacing (pulling down) the frame 320 towards the base 310. 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 also 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 such cases, from the viewpoint of sufficiently reducing the holding force on the object, the amount of displacement of the frame 320, i.e., the pulling 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.

[0159] (S730: Peeling off an object)

[0160] 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 the processing step and the expansion step. The method of peeling off the object is not particularly limited. For example, the above method can be used as a method for transferring an object attached to a holding substrate to the adhesive sheet. As an example, an adsorption member such as a vacuum nozzle 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 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.

[0161] It should be noted that, according to the research of the inventors of this application, when peeling 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. In particular, when peeling thin objects such as components, the object is more likely to break by increasing the adsorption force. 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 is reduced. For example, in the case of 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, it is possible to simultaneously achieve: a high holding force of the adhesive layer 110 when the adhesive sheet holds the object, and a low holding force of the adhesive layer 110 when peeling the object from the adhesive sheet. 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.

[0162] Through the steps described above, an object can be transferred to any transfer target using an adhesive sheet. Furthermore, one embodiment of the invention relates to a method for peeling an object from an adhesive sheet in which the object is held in an adhesive layer. Such a peeling method may include a step of reducing adhesive force, such as S720, and a step of peeling the object, such as S730.

[0163] Furthermore, such a peeling method can be used to manufacture electronic components or semiconductor devices having elements. For example, a method for manufacturing an article according to one embodiment of the present invention may include, in addition to the step of peeling the object from the adhesive sheet according to the above-described peeling method, a step of manufacturing the article by post-processing the object. Figure 7 In the example, post-processing steps for the object are performed in S740. The type of post-processing is not particularly limited. For example, it can include wiring formation, back metal formation, cleaning, plating, monolithization, thin-film forming, and sealing.

[0164] Example

[0165] 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.

[0166] The following compounds were used in the examples and comparative examples.

[0167] <(A) Composition: Acrylic ester copolymer>

[0168] The following substances were used as acrylic ester copolymers.

[0169] (A1) An acrylic copolymer (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 ray-reactive group via hydroxyl groups into the polymer side chain (mass average molecular weight (Mw): 520,000, number average molecular weight (Mn): 155,000).

[0170] <(B) Component: Crosslinking agent>

[0171] As a crosslinking agent, an isocyanurate-type polyisocyanate derived from hexamethylene diisocyanate was used.

[0172] <(C) Component: Photopolymerization initiator>

[0173] The following substances were used as photopolymerization initiators.

[0174] (C1) 1-Hydroxycyclohexylphenyl ketone.

[0175] (Examples 1-4)

[0176] An adhesive composition was prepared by dissolving the amounts of acrylate copolymer (A1), crosslinking agent (B), and photopolymerization initiator (C1) shown in Table 1 in toluene. Table 1 shows the parts by weight of the solid components of each material.

[0177] The adhesive composition was applied to the release surface of a release sheet (micro-embossed release sheet) with a concave shape, and the resulting coating was dried at 100°C for 2 minutes, thereby forming an adhesive layer with a thickness of 25 μm. The concave-convex shape of the formed adhesive layer on the surface is consistent with... Figure 2A Similarly, the columns are arranged in a lattice pattern. The spacing P between the columns in the adhesive sheet is 20 μm. Furthermore, Figure 4A The height (H) of each column shown is 8 μm, the diameter (T) of the front end is 8 μm, and the diameter (W) of the base is 16 μm. It should be noted that the release sheet described above uses a release sheet with a concave shape on its surface that complements this uneven shape.

[0178] On the adhesive layer thus obtained, the unembossed side of the substrate (ethylene methacrylate copolymer (EMAA) film, acid content 9% by mass, one side is embossed to form a textured surface, thickness 80 μm, tensile modulus 160 MPa) is bonded, thereby producing an adhesive sheet.

[0179] (Comparative Example 1)

[0180] In forming the adhesive layer, in addition to heating and drying, an ultraviolet irradiation machine (Heraeste) was used with an irradiation of 130 mW / cm². 2 Light intensity 210 mJ / cm 2 The adhesive composition was prepared in the same manner as in Example 1, except that it was irradiated with ultraviolet light, and an adhesive sheet was made.

[0181] <Adhesion Strength Evaluation>

[0182] The adhesive strength of the adhesive layer used in each embodiment and comparative example was measured as follows. Using the adhesive compositions obtained in each embodiment and comparative example, an adhesive layer with a thickness of 25 μm was formed on the release sheet. The method for forming the adhesive layer, including heating conditions and ultraviolet irradiation conditions, was the same as in each embodiment and comparative example, and the same unevenness was formed on the adhesive layer as in each embodiment and comparative example.

[0183] A 25mm × 200mm sample was cut from the obtained adhesive layer to determine the adhesion strength before UV irradiation. A release sheet was peeled from the adhesive layer, and the exposed adhesive layer surface was pressed onto the Si wafer using a laminator. After pressing, the sample was left to stand at 23°C and 50% RH (relative humidity) for 1 hour, thus preparing the adhesion strength test specimen.

[0184] For the adhesive strength test specimens prepared in this manner, the adhesive strength was measured using a tensile testing machine (manufactured by A&D Corporation, product name "Tensilon (registered trademark)") at an environment of 23°C and 50% RH (relative humidity), based on JIS Z0237:2000, by the 180° peel method at a tensile speed of 300 mm / min. The adhesive strength measured in this way is referred to as the adhesive strength before ultraviolet irradiation.

[0185] Furthermore, after preparing the adhesive strength test specimens using the same method, the specimens were subjected to ultraviolet irradiation using a Heraeus UV irradiation machine (manufactured by Heraeus) at an illuminance of 130 mW / cm². 2 Light intensity 210 mJ / cm 2 The material was then irradiated with ultraviolet light. The adhesive strength was then measured using the same method. This measured adhesive strength is referred to as the adhesive strength after ultraviolet irradiation.

[0186] <Pick-up rating>

[0187] The retrievalability of the objects held by the adhesive sheets obtained in each embodiment and comparative example was evaluated as follows. First, the adhesive layer of the adhesive sheet obtained in each embodiment and comparative example was attached to an annular frame (made of stainless steel, with an inner diameter of 194 mm), and the adhesive sheet was cut to fit the outer diameter of the annular frame.

[0188] Next, a wafer substrate (a polished silicon wafer, 6 inches, 50 μm thick) was fixed to a separately prepared dicing tape. Then, multiple components (silicon chips, 8 mm × 8 mm × 50 μm in size) were obtained by dicing the wafer substrate into 8 mm × 8 mm squares. The obtained components were attached to the adhesive layer on the inner center of the aforementioned annular frame, with the polished surface attached to the adhesive layer. Attachment was performed by lamination at room temperature (23°C). Then, the components were transferred from the dicing tape to the adhesive sheet by peeling off the dicing tape. Thus, an adhesive sheet containing multiple components and supported by an annular frame was obtained as an evaluation sample.

[0189] 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.

[0190] Evaluation samples irradiated with ultraviolet light were placed on a pickup device (manufactured by Canon Machinery Co., Ltd., product name "BESTEM-D510"). After the adhesive sheet was expanded, the component was picked up using a vacuum suction nozzle. It should be noted that the expansion of the adhesive sheet was as follows... Figures 5A-5B The process is as shown. That is, with the component supported by the stage 310 across the adhesive sheet, the adhesive sheet is expanded by pulling the frame 320, which serves as a ring frame, down 10 mm relative to the stage 310. Furthermore, this evaluation assesses whether the component can be picked up without using a pin to push against the side of the adhesive sheet opposite to the component to be adhered to (substrate). If the component can be picked up without damage, it is evaluated as "picking up is possible" (A). If the component is damaged during picking, cannot be picked up, or fails to transfer from the wafer substrate to the adhesive sheet, it is evaluated as "not picking up" (F).

[0191] These evaluation results are shown in Table 1.

[0192] [Table 1]

[0193]

[0194] As shown in Table 1, the adhesive layers of the adhesive sheets in Examples 1-4 possess sufficiently high adhesive strength to maintain the components before ultraviolet irradiation. Furthermore, the adhesive strength of the adhesive layers decreased significantly upon ultraviolet irradiation. One reason for this effect is speculated to be the increase in elasticity of the adhesive layer through energy-reactive treatment. Moreover, for both before and after ultraviolet irradiation, a tendency to decrease adhesive strength by increasing the amount of crosslinking agent (B) can be observed.

[0195] Furthermore, through the evaluation of the pick-up performance of the adhesive sheets in Examples 1 to 4, it was confirmed that the adhesive sheets could hold the components before ultraviolet irradiation and could pick up the components from the adhesive sheets after ultraviolet irradiation.

[0196] On the other hand, as in Comparative Example 1, when an adhesive sheet is used after energy is applied to form an uneven surface on the adhesive layer and the cross-linking reaction is carried out, the adhesive force is low, so the component cannot be completely transferred from the cut tape to the adhesive sheet.

[0197] It should be noted that, for the adhesive sheet of Example 1, the above-mentioned pickup performance evaluation was performed without ultraviolet irradiation, and the result was that the component could not be picked up. It is believed that in order to pick up easily broken objects (e.g., thin components) used in the above-mentioned pickup performance evaluation, the adhesive strength of the adhesive layer needs to be reduced.

[0198] As described above, by using a method that applies energy to an adhesive sheet holding an object and then peels the object off, both the holding force and ease of peeling can be achieved. Furthermore, by using a process that expands the adhesive sheet in the planar direction, the ease of peeling can be further improved. This method is particularly suitable for peeling easily breakable objects from adhesive sheets.

[0199] The invention is not limited to the above-described embodiments. Within the scope of the invention's intent, various modifications and alterations are possible.

[0200] This application claims priority based on the following patent applications: Japanese Patent Application No. 2024-046979, No. 2024-046980, No. 2024-046981, No. 2024-046982, No. 2024-170363, and No. 2024-170369, all of which are incorporated herein by reference.

Claims

1. A peeling method, said peeling method being a method of peeling an object from an adhesive sheet, said adhesive sheet having a substrate and an energy-reactive adhesive layer having an uneven surface, and said object being held in said adhesive layer. The stripping method includes: A process for applying energy to the adhesive sheet; An expansion process that extends the adhesive sheet in the planar direction; as well as After the energy is applied and extended in the direction of the surface, a peeling process is performed to detach the object from the adhesive layer of the adhesive sheet.

2. The peeling method according to claim 1, wherein, The adhesive layer is reactive to energy rays. In the processing step, the adhesive sheet is irradiated with energy rays.

3. The peeling method according to claim 2, wherein, In the processing step, the adhesive layer is irradiated with energy rays of an amount that reduces the adhesive force to less than 70 mN / 25 mm.

4. The peeling method according to claim 1, wherein, The thickness of the object is less than 50 μm.

5. The peeling method according to claim 1, wherein, In the expansion process, the adhesive sheet is expanded by more than 1% in the surface direction.

6. The peeling method according to claim 1, wherein, The content of the polymer having energy-curable groups is 70 to 100% by mass relative to the total amount of the components constituting the adhesive layer.

7. The peeling method according to claim 1, wherein, The adhesive layer has an acrylic resin having energy-curable groups and is cross-linked by an isocyanate-based cross-linking agent.

8. The peeling method according to claim 1, wherein, The tensile modulus of elasticity of the substrate is below 2500 MPa.

9. The peeling method 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 1 μm and less than 100 μm.

10. The peeling method according to claim 1, wherein, The adhesive layer has multiple protrusions, and the height of the multiple protrusions is uniform.

11. The peeling method according to claim 1, wherein, In the peeling process, an adsorption member is used to peel the object from the adhesive layer of the adhesive sheet.

12. The peeling method according to claim 11, wherein, In the peeling process, the object is peeled off from the adhesive layer of the adhesive sheet without applying physical stimulation to the opposite side of the adhesive layer.

13. The peeling method according to claim 11, wherein, In the peeling process, the object is peeled off from the adhesive layer of the adhesive sheet while physical stimulation is applied from the opposite side of the adhesive layer.

14. A method for manufacturing an article, the method comprising: The process of peeling the object from the adhesive sheet according to the peeling method according to claim 1; as well as The process of manufacturing articles by post-processing the object.

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