Adhesive sheet and peeling method

Abstract

According to the present invention, an object held on an adhesive sheet can be picked up by using a milder operation. An adhesive sheet is provided with a base material and an adhesive layer having irregularities on the surface thereof. The adhesive layer has a base portion and a protruding portion, wherein the base portion is composed of a concave portion with the smallest thickness of the adhesive layer in the thickness direction of the adhesive layer and a portion of a surface opposite to the surface with the concave and convex portions, and the adhesive layer satisfies relational expression (1). The relational expression (1) is 0.25 lt; s / Hlt; (In relational expression (1), S represents the thickness of the base portion, and H represents the height of the protruding portion).

Description

Technical Field

[0001] The invention relates to an adhesive sheet and a peeling method. Background Art

[0002] The adhesive sheet can be used to temporarily hold an object. For example, in order to transfer the object to a desired location, such an adhesive sheet can be used.

[0003] The adhesive sheet has various shapes depending on its use. For example, Patent Document 1 describes providing grooves on the surface of the adhesive layer so that bubbles can be removed after attachment.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-147418 Summary of the invention

[0007] Problems to be solved by the invention

[0008] The object temporarily held on the adhesive sheet needs to be peeled off (picked up) from the adhesive sheet in the subsequent process. In particular, when holding an object that is vulnerable to external forces, such as a semiconductor component, it is ideal that the holding force of the sheet on the object is not too high in order to prevent the object from being damaged during peeling.

[0009] The present invention aims to enable picking up an object held on an adhesive sheet with a gentler operation.

[0010] Solutions for solving problems

[0011] The inventors of the present invention have repeatedly conducted research and have found that by providing projections and depressions on the surface of the adhesive layer of the adhesive sheet, the force required to pick up an object from the adhesive sheet can be reduced, thereby solving the above-mentioned problem. The inventors of the present invention have further conducted various researches and have completed the present invention.

[0012] That is, the present invention relates to the following [1] to

[14] .

[0013] [1] An adhesive sheet comprising a substrate and an adhesive layer having a surface with projections and depressions, wherein the adhesive layer comprises a base portion consisting of a portion extending from a recessed portion where the thickness of the adhesive layer is the smallest to a portion of a surface opposite to the surface having projections and depressions in a thickness direction of the adhesive layer, and a projection provided on the base portion, and the adhesive layer satisfies the following relational expression (1).

[0014] Relation (1): 0.25

[0015] (In the relational expression (1), S represents the thickness of the base portion, and H represents the height of the convex portion.)

[0016] ​[2] The adhesive sheet according to [1], wherein the base portion has a uniform thickness.

[0017] [3] The adhesive sheet described in any one of [1] to [2], wherein the adhesive layer has a plurality of protrusions, and the heights of the plurality of protrusions are uniform.

[0018] [4] The adhesive sheet described in any one of [1] to [3], wherein the height of the protrusion is not less than 1 µm and not less than 15 µm.

[0019] [5] The adhesive sheet described in any one of [1] to [4], wherein the thickness of the base portion is not less than 1 µm and not less than 50 µm.

[0020] [6] The adhesive sheet described in any one of [1] to [5], wherein the base portion and the protrusion are integrally formed.

[0021] [7] An adhesive sheet as described in any one of [1] to [6], characterized in that the adhesive layer has a plurality of convex portions separated from each other by boundaries determined by concave portions, and the pitch between the plurality of convex portions is greater than 1 µm and less than 100 µm.

[0022] [8] The adhesive sheet according to any one of [1] to [7], wherein the shear storage modulus of the adhesive layer is 0.001 MPa to 100 MPa.

[0023] [9] The adhesive sheet described in any one of [1] to [8], wherein the tensile modulus of the substrate is 2500 MPa or less.

[0024]

[10] The adhesive sheet according to any one of [1] to [9], wherein the adhesive sheet is a component fixing sheet.

[0025]

[11] The adhesive sheet according to any one of [1] to [9], wherein the adhesive sheet is a sheet for element transfer.

[0026]

[12] An adhesive sheet as described in any one of [1] to

[11] , characterized in that the adhesive sheet can expand along the surface direction, and the holding force of the object on the adhesive sheet after expansion is lower than that before expansion.

[0027]

[13] A method for peeling a component from an adhesive sheet, the peeling method comprising: an expansion step of expanding the adhesive sheet as described in any one of [1] to

[12] in a surface direction in which the component is fixed in the adhesive layer; and a peeling step of peeling the component from the adhesive layer of the adhesive sheet after expansion in the surface direction.

[0028]

[14] The peeling method as described in

[13] , further comprising the following step before the expansion step: forming a plurality of elements by cutting the element held by the adhesive layer.

[0029] Effects of the Invention

[0030] Objects held on the adhesive sheet can be picked up with a gentler operation. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0032] Figure 2A This is a cross-sectional view showing an example of the concavities and convexities of the sheet.

[0033] Figure 2B This is a cross-sectional view showing an example of the concavities and convexities of the sheet.

[0034] Figure 3A This is a plan view showing an example of the concavities and convexities of the sheet.

[0035] Figure 3B This is a plan view showing an example of the concavities and convexities of the sheet.

[0036] Figure 3C This is a plan view showing an example of the concavities and convexities of the sheet.

[0037] Figure 4A This is a cross-sectional view showing an example of the concavities and convexities of the sheet.

[0038] Figure 4B This is a cross-sectional view showing an example of the concavities and convexities of the sheet.

[0039] Figure 4C This is a cross-sectional view showing an example of the concavities and convexities of the sheet.

[0040] Figure 5A This is a diagram for explaining a method of expanding a sheet.

[0041] Figure 5B This is a diagram for explaining a method of expanding a sheet.

[0042] Figure 6 This is a flowchart of a device peeling method and a transfer method according to one embodiment. DETAILED DESCRIPTION

[0043] Hereinafter, the embodiments are described in detail with reference to the accompanying drawings. It should be noted that the following embodiments do not limit the technical solutions of the claims, and the combination of features described in the embodiments is not necessarily required for the invention. Two or more of the multiple features described in the embodiments can be combined arbitrarily. In addition, the same figure mark is marked for the same or similar structure, and repeated description is omitted.

[0044] (definition)

[0045] In this specification, the mass average molecular weight (Mw) and the number average molecular weight (Mn) are values ​​measured by size exclusion chromatography in terms of standard polystyrene, specifically values ​​measured in accordance with JIS K7252-1: 2016. In addition, in this specification, "(meth)acrylic acid" refers to both "acrylic acid" and "methacrylic acid", and the same applies to other similar terms.

[0046] In this specification, when one or more lower limits and one or more upper limits of a numerical range (such as a range of content, etc.) are recorded, it can be understood that any lower limit and upper limit and combination thereof are recorded. For example, the description of preferably 1 or more, more preferably 2 or more, further preferably 3 or more and preferably 9 or less, more preferably 8 or less, and further preferably 7 or less indicates that the numerical range can be any 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.

[0047] (Composition of the film)

[0048] An adhesive sheet according to one embodiment of the present invention comprises a substrate 120 and an adhesive layer 110 having a concave-convex surface. The adhesive sheet is used to temporarily hold a component and transfer it to a transfer destination. For example, the adhesive sheet can be used to receive a component held on another holding substrate, temporarily hold the component, and transfer the component to a desired position of the transfer destination. The substrate 120 can support the adhesive layer 110. Figure 1 In this specification, the adhesive sheet is sometimes referred to as simply a sheet.

[0049] (Base material)

[0050] The substrate 120 functions as a support body that supports the adhesive layer 110. The substrate 120 is located on the surface of the adhesive layer 110 that is opposite to the surface having the projections and recesses.

[0051] As described later, the sheet of this embodiment can be expanded. From this point of view, a flexible substrate can be used as the substrate 120. Moreover, by using a flexible substrate as the substrate 120, the cushioning property when holding the element can be improved, or the sheets can be easily stacked, or the sheets can be made into a roll shape. As the substrate 120, for example, a resin film can be used. The resin film is a film using a resin-based material as the main material, and can be formed of a resin material or contain additives in addition to the resin material. The resin film may also have laser transmittance.

[0052] Specific examples of resin films include polyethylene films such as low-density polyethylene (LDPE) films, linear low-density polyethylene (LLDPE) films, and high-density polyethylene (HDPE) films, polyolefin films such as polypropylene films, polybutylene films, polybutadiene films, poly(4-methyl-1-pentene) films, ethylene-norbornene copolymer films, and norbornene resin films; ethylene copolymer films such as ethylene-vinyl acetate copolymer films, ethylene-(meth)acrylic acid copolymer films, and ethylene-(meth)acrylic acid ester copolymer films; polyvinyl chloride films such as polyvinyl chloride films and vinyl chloride copolymer films; polyester films such as polyethylene terephthalate films and polybutylene terephthalate films; polyurethane films; polyimide films; polystyrene films; polycarbonate films; and fluororesin films. In addition, films containing a mixture of two or more materials, crosslinked films formed by crosslinking the resins forming these films, and modified films such as ionomer films can also be used. Alternatively, the substrate 120 may be a laminated film in which two or more resin films are laminated.

[0053] From the viewpoint of facilitating the expansion of the sheet, the substrate 120 is preferably a polyolefin film or a vinyl chloride copolymer film. As polyolefin films, for example, copolymers containing unsubstituted olefins such as ethylene or propylene as structural units, such as polyethylene films, polypropylene films, and ethylene copolymers including ethylene-methacrylic acid copolymers (EMAA), etc. As vinyl chloride copolymer films, for example, vinyl chloride-vinylidene chloride copolymer films, vinyl chloride-vinyl acetate copolymer films, and vinyl chloride-ethylene copolymer films, etc., can be exemplified. The form of such copolymers is not particularly limited, and may 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.

[0054] The thickness of the substrate 120 is not particularly limited. From the viewpoint of achieving both support and roll windability, it is preferably greater than 10µm, more preferably greater than 25µm, and further preferably greater than 40µm. On the other hand, it is preferably less than 500µm, more preferably less than 200µm, further preferably less than 150µm, further preferably less than 150µm, further preferably less than 120µm, and particularly preferably less than 90µm.

[0055] In order to make the sheet easily and uniformly expand, the tensile modulus of the substrate 120 is preferably 50 MPa or more, more preferably 80 MPa or more, and further preferably 120 MPa or more, and preferably 2500 MPa or less, more preferably 1000 MPa or less, and further preferably 500 MPa or less. In this specification, the tensile modulus is measured in accordance with JIS K7161-1:2014.

[0056] Similarly, in order to facilitate sheet expansion, the elongation at break of the substrate 120 is preferably 105% or more, more preferably 150% or more, and even more preferably 250% or more. In this specification, the elongation at break is measured in accordance with JIS K 7127:1999.

[0057] (Adhesive layer)

[0058] The adhesive layer 110 is an adhesive layer and may contain a resin. As described above, the surface of the adhesive layer 110 has concavities and convexities. It should be noted that the sheet may have two or more adhesive layers 110. For example, the sheet may have a laminate of one or more adhesive layers 110.

[0059] (Composition of adhesive layer)

[0060] Examples of resins contained in the adhesive layer 110 include: polyisobutylene resins, polybutadiene resins, and rubber resins such as styrene-butadiene resins, acrylic resins, urethane resins, polyester resins, olefin resins, silicone resins, and polyvinyl ether resins. The adhesive layer may have heat resistance, and polyimide resins and silicone resins may be used as materials for the heat-resistant adhesive layer 110. The adhesive layer 110 may include a copolymer having two or more structural units. The form of the copolymer is not particularly limited, and may be any of a block copolymer, a random copolymer, an alternating copolymer, and a graft copolymer.

[0061] The resin contained in the adhesive layer 110 is preferably an adhesive resin that has adhesiveness alone. In addition, the resin is preferably a polymer having a mass average molecular weight (Mw) of 10,000 or more. From the viewpoint of improving the holding property, the mass average molecular weight (Mw) of the resin is preferably 10,000 or more, more preferably 70,000 or more, and further preferably 140,000 or more. In addition, from the viewpoint of suppressing the storage modulus below a specified value, the Mw is preferably 2 million or less, and more preferably 1.2 million or less. In addition, from the viewpoint of improving the holding property, the number average molecular weight (Mn) of the resin is preferably 10,000 or more, more preferably 50,000 or more, and further preferably 100,000 or more. In addition, from the viewpoint of suppressing the storage modulus below a specified value, the Mn is preferably 2 million or less, more preferably 1.5 million or less, and further preferably 1.2 million or less. It should be noted that, as described later, when the adhesive layer 110 includes a resin derived from an energy-reactive resin, its 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 cross-linking reaction is performed by energy imparting. In addition, the glass transition temperature (Tg) of the resin is preferably above -75°C, more preferably above -70°C, and preferably below 5°C, more preferably below -20°C. By making Tg within this range, it is easy to make the retention and storage modulus of the obtained adhesive layer 110 within the range described later.

[0062] The amount of resin contained in the adhesive layer 110 relative to the total amount of components constituting the adhesive layer 110 can be appropriately set according to the required holding power and storage modulus of the adhesive layer 110, and is preferably 30 mass % or more, more preferably 50 mass % or more, further preferably 70 mass % or more, further preferably 80 mass % or more, further preferably 90 mass % or more, and preferably 99.99 mass % or less, more preferably 99.95 mass % or less, further preferably 99.90 mass % or less, further preferably 99.80 mass % or less, and further preferably 99.50 mass % or less.

[0063] From the viewpoint of the morphological stability of the concavo-convex shape on the surface of the adhesive layer, the shear storage modulus of the adhesive layer 110 is preferably 0.001 MPa or more, more preferably 0.01 MPa or more, further preferably 0.03 MPa or more, and further preferably 0.07 MPa or more. On the other hand, from the viewpoint of suppressing positional deviation when holding the element, it is preferred that the shear storage modulus of the adhesive layer 110 is low. From this viewpoint, the shear storage modulus of the adhesive layer 110 is preferably 100 MPa or less, more preferably 50 MPa or less, further preferably 20 MPa or less, and particularly preferably 5 MPa or less. In this specification, the shear storage modulus is measured in accordance with JIS K7244-1:1998. Specifically, the shear storage modulus of the adhesive layer 110 can be measured by preparing a cylindrical sample with a thickness of 3 mm and a diameter of 8 mm, using a viscoelasticity measuring device, and measuring the shear storage modulus of the sample by a torsional shear method at 1 Hz and 23°C.

[0064] In one embodiment, the resin contained in the adhesive composition forming the adhesive layer 110 may include a thermoplastic resin. That is, the adhesive layer 110 may be formed of a thermoplastic resin. In the case of using a thermoplastic resin, the resin is softened by heating, and it is easy to form concave and convex shapes on the adhesive layer 110, and it is easy to maintain the concave and convex shapes formed by cooling. Examples of thermoplastic resins include rubber resins, acrylic resins, urethane resins, and olefin resins. As an example, 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 a monomer.

[0065] Hereinafter, a composition example of the adhesive layer 110 will be described. However, the composition of the adhesive layer 110 is not limited to the following.

[0066] (Acrylic resin (A))

[0067] In one embodiment, the adhesive composition forming the adhesive layer 110 includes an acrylic resin. The acrylic resin is a resin containing (meth) acrylic acid or (meth) acrylic acid ester as a monomer. From the perspective of improving adhesion, the mass average molecular weight (Mw) of the acrylic resin is preferably 10,000 or more, more preferably 100,000 or more, and further preferably 500,000 or more. In addition, from the perspective of suppressing the storage modulus to a specified value or less, the Mw is preferably 2 million or less, more preferably 1.5 million or less, and further preferably 1.2 million or less.

[0068] The glass transition temperature (Tg) of the acrylic resin is preferably -75°C or higher, more preferably -70°C or higher, and preferably 5°C or lower, more preferably -20°C or lower. When Tg is within this range, it is easy to obtain the adhesive layer 110 having the above storage modulus.

[0069] When the acrylic resin has two or more structural units, the glass transition temperature (Tg) of the acrylic resin can be calculated using the Fox equation. The Tg of the monomer from which the structural unit used in this case is derived can be the value described in the polymer data handbook or the adhesive handbook.

[0070] Examples of the (meth)acrylate ester constituting the acrylic resin include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, amyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, myristyl (meth)acrylate, pentadecyl (meth)acrylate, palmityl (meth)acrylate, heptadecyl (meth)acrylate, and stearyl (meth)acrylate. Examples of the (meth)acrylate ester constituting the acrylic resin include alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, amyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, myristyl (meth)acrylate, pentadecyl (meth)acrylate, palmityl (meth)acrylate, heptadecyl (meth)acrylate, and stearyl (meth)acrylate. Alkyl (meth)acrylates having a chain structure in which the alkyl group has 1 to 18 carbon atoms; cycloalkyl (meth)acrylates such as isoborneol (meth)acrylate and dicyclopentanyl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate; cycloalkenyl (meth)acrylates such as dicyclopentenyl (meth)acrylate; cycloalkenyloxyalkyl (meth)acrylates such as dicyclopentenyloxyethyl (meth)acrylate; imide (meth)acrylates; glycidyl (meth)acrylate and other (meth)acrylates containing a glycidyl group; hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate and other (meth)acrylates containing a hydroxyl group; N-methylaminoethyl (meth)acrylate and other (meth)acrylates containing a substituted amino group. Here, the "substituted amino group" refers to a group having a structure in which one or two hydrogen atoms of an amino group are substituted with a group other than a hydrogen atom.

[0071] The acrylic resin may be, for example, a resin obtained by copolymerizing, in addition to (meth)acrylate or (meth)acrylic acid, one or two or more monomers selected from itaconic acid, vinyl acetate, acrylonitrile, styrene, and N-methylol acrylamide.

[0072] The monomers constituting the acrylic resin may be one kind or two or more kinds. When there are two or more kinds, the combination and ratio of the monomers may be arbitrarily selected.

[0073] In one embodiment, the acrylic resin contains a monomer having a hydroxyl group as a structural unit. In addition to the hydroxyl group, the acrylic resin may also have a functional group that can be bonded to other compounds, such as a vinyl group, a (meth)acryloyl group, an amino group, a carboxyl group, and an isocyanate group. These functional groups, including the hydroxyl group of the acrylic resin, may be bonded to other compounds via a crosslinking agent (C) described later, or may be directly bonded to other compounds without the crosslinking agent (C).

[0074] The amount of acrylic resin in the total amount of resin in the adhesive composition can be appropriately set according to the required adhesion and storage modulus of the adhesive layer 110, and is preferably 0 mass % or more, more preferably 10 mass % or more, further preferably 20 mass % or more, further preferably 50 mass % or more, and preferably 100 mass % or less, more preferably 95 mass % or less, further preferably 80 mass % or less, and further preferably 60 mass % or less.

[0075] (Energy-responsive resin (B))

[0076] In one embodiment, the adhesive composition forming the adhesive layer 110 includes an energy-reactive resin (B). The energy-reactive resin (B) refers to a resin whose elastic modulus is increased by applying energy. It should be noted that the energy-reactive resin may be a resin derived from an energy-reactive monomer. In this case, the energy-reactive resin is a resin obtained by applying energy to polymerize the energy-reactive monomer.

[0077] As energy-reactive resins, energy-ray reactive resins and heat-reactive resins can be exemplified. Energy-ray reactive resins refer to resins whose elastic modulus is increased by irradiation with energy rays. For example, the energy-reactive resin can be an energy-ray curable resin. In addition, a heat-reactive resin refers to a resin whose elastic modulus is increased by heating. The resin contained in the adhesive layer 110 is more preferably an energy-reactive resin derived from a thermoplastic, and more preferably an energy-ray reactive resin derived from a thermoplastic. The type of energy ray is not particularly limited, and for example, ultraviolet rays, electron beams, or ionizing radiation can be exemplified. The energy ray is preferably ultraviolet rays, that is, the resin is preferably an ultraviolet reactive resin.

[0078] Thermoplastic energy-reactive resin refers to an energy-reactive resin that has thermoplasticity at least before energy is applied. In addition, a resin derived from an energy-reactive resin means that the resin is obtained from an energy-reactive resin. For example, a resin derived from an energy-reactive resin is a cross-linked energy-reactive resin.

[0079] When such an energy-reactive resin is used, the formed concavo-convex shape can be easily maintained by applying energy (for example, irradiating with energy rays) after the concavo-convex shape is formed on the resin.

[0080] As such an energy-reactive resin, a polymer having a polymerizable functional group introduced therein can be used. The polymerizable functional group is a functional group that undergoes crosslinking by imparting energy (e.g., irradiation with energy rays). Examples of the polymerizable functional group include alkenyl groups such as vinyl and allyl, (meth)acryloyl, oxetanyl, and epoxy groups.

[0081] For example, as the energy-reactive resin, a diene rubber composed of a polymer having a polymerizable functional group at the main chain end and / or side chain can be used. Diene rubber refers to a rubber-like polymer having a double bond in the polymer main chain. As a specific example of diene rubber, a polymer using butadiene or isoprene as a monomer (i.e., having a butene diyl or a pentene diyl as a structural unit) can be exemplified. As the energy-reactive resin, polybutadiene resin (PB resin), styrene-butadiene-styrene block copolymer (SBS resin), and styrene-isoprene-styrene block copolymer are preferred. These resins can be used as ultraviolet reactive resins.

[0082] From the viewpoint of facilitating the maintenance of the concavo-convex shape of the adhesive layer 110, the average value of the number of polymerizable functional groups per molecule in these energy-reactive resins is preferably 1.5 or more, more preferably 2 or more. On the other hand, from the viewpoint of improving the adhesion and flexibility of the adhesive layer 110, the average value is preferably 20 or less, more preferably 15 or less, and further preferably 10 or less.

[0083] The adhesive layer 110 may include one resin or two or more resins. The adhesive layer 110 of one embodiment includes a liquid resin, a resin derived from an energy-reactive liquid resin, or a resin derived from an energy-reactive monomer, in addition to a thermoplastic resin or a resin derived from a thermoplastic energy-reactive resin. A liquid resin refers to a resin that is a liquid at room temperature (25°C) before mixing. In addition, an energy-reactive liquid resin refers to an energy-reactive resin that is a liquid at room temperature (25°C) before mixing and before energy is applied. In addition, a resin derived from an energy-reactive monomer is a resin obtained by polymerizing an energy-reactive monomer by applying energy. By adding a liquid resin or a monomer as described above, it is easy to control the holding power and storage modulus of the adhesive layer 110.

[0084] In order to easily maintain the concavo-convex shape of the adhesive layer 110, it is preferred that the adhesive layer 110 of one embodiment contains a resin derived from an energy-reactive liquid resin. Examples of such liquid resins include diene rubbers, and as a specific example, polybutadiene resins using butadiene as a monomer may be used.

[0085] The adhesive layer 110 of another embodiment includes a combination of any resin and a resin derived from an energy-reactive liquid resin or an energy-reactive monomer. For example, the adhesive layer 110 may include an acrylic resin (A) and a resin derived from an energy-reactive liquid resin or an energy-reactive monomer. According to this combination, after forming the concavoconvexity of the film of the mixture of the acrylic resin (A) and the energy-reactive liquid resin or the energy-reactive monomer, energy is applied (for example, irradiated with energy rays) to polymerize the energy-reactive liquid resin or the energy-reactive monomer, thereby making it easy to maintain the formed concavoconvex shape.

[0086] Examples of energy-reactive monomers include difunctional or polyfunctional compounds into which polymerizable functional groups such as vinyl and allyl groups, (meth)acryloyl groups, oxetane groups, and epoxy groups are introduced. Preferred examples of energy-reactive monomers include poly(meth)acrylates such as difunctional (meth)acrylates. As described above, the adhesive layer 110 may contain an energy-ray-curable resin containing poly(meth)acrylates as structural units. Specific examples of poly(meth)acrylates include cycloalkyl di(meth)acrylates such as tricyclodecane dimethanol diacrylate.

[0087] In addition, the ratio of the energy-responsive resin (B) to the total amount of the components constituting the adhesive layer 110 can be selected according to the required holding property and storage modulus of the adhesive layer 110. For example, the ratio is preferably 1% by mass or more, more preferably 5% by mass or more, further preferably 8% by mass or more, further preferably 10% by mass or more, and preferably 30% by mass or less, more preferably 25% by mass or less.

[0088] In addition, when the adhesive layer 110 includes an acrylic resin (A) and an energy-reactive resin (B), the amount of the energy-reactive resin relative to the acrylic resin can be selected according to the required retention and storage modulus of the adhesive layer 110. For example, the amount of the energy-reactive resin relative to 100 parts by mass of the acrylic resin is preferably 1 part by mass or more, more preferably 5 parts by mass or more, further preferably 8 parts by mass or more, particularly preferably 10 parts by mass or more, and preferably 30 parts by mass or less, more preferably 25 parts by mass or less. In this case, the energy-reactive resin is, for example, an energy-ray curable resin, and is, for example, a resin derived from an energy-ray curable monomer. Here, parts by mass is a mass reference of solid matter, and the following is also a mass reference unless otherwise specified in advance.

[0089] (Other ingredients of adhesive layer)

[0090] The adhesive composition forming the adhesive layer 110 may include components other than the resin. For example, the adhesive composition may include one or more of a crosslinking agent (C), a photopolymerization initiator (D), and other additives.

[0091] Examples of the crosslinking agent (C) include isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, and metal chelate crosslinking agents. These crosslinking agents may be used alone or in combination of two or more.

[0092] Among these crosslinking agents, isocyanate crosslinking agents are preferred from the viewpoints of improving cohesion to improve adhesion, easy availability, etc. As isocyanate crosslinking agents, for example, aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; alicyclic polyisocyanates such as dicyclohexylmethane-4,4'-diisocyanate, dicycloheptane triisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, methylenebis(cyclohexyl isocyanate), 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, and hydrogenated xylylene diisocyanate; non-cyclic aliphatic polyisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate; and polyisocyanate compounds, etc. Examples of the isocyanate crosslinking agent include trimethylolpropane adduct-type modified products of the polyisocyanate compound, biuret-type modified products obtained by reacting with water, and isocyanurate-type modified products containing an isocyanurate ring.

[0093] The adhesive composition may contain one crosslinking agent or two or more crosslinking agents. From the perspective of appropriately performing a crosslinking reaction, the content of the crosslinking agent in the adhesive composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, further preferably 0.5% by mass or more, particularly preferably 0.8% by mass or more, and preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 2% by mass or less.

[0094] For example, the crosslinking agent may be a crosslinking agent for an acrylic resin (A). For example, an isocyanate crosslinking agent of an isocyanurate type modified body may be used as a crosslinking agent for an acrylic resin containing a monomer having a hydroxyl group as a structural unit. In this case, the amount of the crosslinking agent relative to the acrylic resin may be selected in such a way that a crosslinking reaction can be appropriately performed. For example, the amount of the crosslinking agent relative to 100 parts by mass of the acrylic resin is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, further preferably 0.5 parts by mass or more, particularly preferably 1.0 parts by mass or more, and preferably 5 parts by mass or less, more preferably 4 parts by mass or less, further preferably 2 parts by mass or less.

[0095] The photopolymerization initiator (D) initiates a crosslinking reaction by applying energy (e.g., irradiation with energy rays). When the adhesive composition contains the energy-reactive resin (B), the adhesive layer 110 further contains the photopolymerization initiator (D), so that the crosslinking reaction proceeds even when a relatively low energy is applied.

[0096] Examples of the photopolymerization initiator (D) include 1-hydroxycyclohexyl phenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, 8-chloroanthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0097] The adhesive composition may contain one polymerization initiator or two or more polymerization initiators. The content of the photopolymerization initiator in the adhesive composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 2% by mass or less.

[0098] The adhesive layer 110 may include other additives without particular limitation, and examples thereof include: ultraviolet absorbers such as benzotriazole compounds, oxazole acid amide compounds, or benzophenone compounds; light stabilizers such as hindered amine compounds, benzophenone compounds, or benzotriazole compounds; resin stabilizers such as imidazole resin stabilizers, dithiocarbamate resin stabilizers, phosphorus resin stabilizers, or thioester resin stabilizers; antioxidants such as phenolic compounds such as hindered phenol compounds, aromatic amine compounds, sulfur compounds, or phosphorus compounds such as phosphate ester compounds, fillers, pigments, extenders, and softeners.

[0099] When the adhesive layer 110 contains these additives, the content of the additives in the adhesive layer 110 is preferably 0.0001 mass % or more, more preferably 0.01 mass % or more, particularly preferably 0.1 mass % or more, further preferably 1 mass % or more, and preferably 20 mass % or less, more preferably 10 mass % or less, further preferably 5 mass % or less.

[0100] (Shape of adhesive layer)

[0101] The adhesive layer 110 of the present embodiment has a surface with irregularities. More specifically, the adhesive layer 110 has a base portion 113 and convex portions 111 provided on the base portion 113 . Figure 4A FIG. 1 is a cross-sectional view of the adhesive layer 110 according to one embodiment, which passes through the protrusion 111 and is perpendicular to the surface of the adhesive layer 110. Figure 4A As shown, the protrusion 111 and the base portion 113 may be integral. That is, the protrusion 111 and the base portion 113 may be formed of the same material. Furthermore, the protrusion 111 and the base portion 113 may be integrally formed.

[0102] like Figure 4A As shown, the adhesive layer 110 may have a convex portion 111 and a concave portion 112. The concave portion 112 is a portion where the thickness of the adhesive layer 110 is the smallest, for example, a portion where the thickness of the adhesive layer 110 is extremely small. In this case, the base portion 113 may be defined as a portion from the concave portion 112 to the surface opposite to the surface having the concave and convex portions in the thickness direction of the adhesive layer 110 ( Figure 4A In the example, the portion of the substrate 120 is in contact with the substrate 120. Figure 4A As shown, the adhesive layer 110 may have a plurality of protrusions 111 on the surface thereof, which are separated from each other and bounded by a base portion 113. Furthermore, each of the plurality of protrusions 111 may be separated by a base portion 113 which is continuous across the entirety of the adhesive layer 110.

[0103] In the present embodiment, the thickness (S) of the base portion 113 and the height (H) of the protrusion 111 satisfy the following relational expression (1).

[0104] Relation (1): 0.25

[0105] According to the research of the inventors of this case, by forming concave-convex portions on the adhesive layer 110, the picking force required to pick up an object from the adhesive sheet can be reduced. In particular, by forming concave-convex portions on the adhesive layer 110 in a manner that satisfies the relationship (1), the picking force required to pick up an object from the adhesive sheet can be further reduced. The inventors of this case believe that the reason is that the concave portion 112 also helps to hold the object due to the deformation of the surface of the adhesive layer 110, and it is easy to peel the object from the concave portion 112 when the height (H) of the convex portion 111 is relatively large. In addition, the inventors of this case believe that the reason is also that when the thickness (S) of the base portion 113 is relatively small, the surface of the adhesive layer 110 is not easy to deform, so it is easy to peel the object from the concave portion 112.

[0106] As described above, from the perspective of reducing the pickup force required to pick up an object from the adhesive sheet, the value of S / H is less than 4.75, preferably less than 4.25, more preferably less than 3.50, further preferably less than 3.00, further preferably less than 2.50, further preferably less than 2.00, further preferably less than 1.75. On the other hand, from the perspective of improving the holding force, the value of S / H exceeds 0.25, preferably exceeds 0.50, more preferably exceeds 0.75, and further preferably exceeds 1.00.

[0107] In one embodiment, from the viewpoint of reducing the pickup force, the height (H) of the protrusion 111 is preferably 1 µm or more, more preferably 2 µm or more, and further preferably 3 µm or more. On the other hand, from the viewpoint of improving the morphological stability, the height (H) of the protrusion 111 is preferably 20 µm or less, more preferably 15 µm or less, and further preferably 10 µm or less.

[0108] In addition, from the perspective of reducing the pickup force, the thickness (S) of the base portion 113 is preferably 50 µm or less, more preferably 40 µm or less, further preferably 30 µm or less, and further preferably 20 µm or less. In addition, from the perspective of improving the holding force, the thickness (S) of the base portion 113 is preferably 1 µm or more, more preferably 3 µm or more, and further preferably 5 µm or more.

[0109] ​In one embodiment, the base portion 113 has a uniform thickness. For example, the thickness of the adhesive layer 110 of each of the plurality of recesses 112 included in the adhesive layer 110 may be uniform. In addition, in one embodiment, the heights of the plurality of protrusions 111 included in the adhesive layer 110 are uniform. On the other hand, the thickness of the base portion 113 does not need to be uniform, and the heights of the protrusions 111 do not need to be uniform. In this case, in at least a portion of the adhesive layer 110, at least half of the adhesive layer 110, or the entire adhesive layer 110, the height (H) of the protrusions 111, the thickness (S) of the base portion 113, or the value of the above S / H are included in the above range.

[0110] As an example, the adhesive layer 110 may include a plurality of first convex portions having a first uniform height and a plurality of second convex portions having different heights. Here, the plurality of second convex portions may have a second uniform height. For example, the convex portion 111 may be composed of such a first convex portion and a second convex portion. As another example, the adhesive layer 110 may have a plurality of convex portions 111 having random heights.

[0111] Figure 2A 2C is a side view showing the shape of the adhesive layer 110, FIG. 3A to FIG. 3C It is a plan 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 1 shows an example of the adhesive layer 110 after expansion. Figure 2A 2C shows the element 140 held by the protrusion 111 of the adhesive layer 110, and FIG. 3A to FIG. 3C The element 140 held by the protrusion 111 is omitted.

[0112] like Figure 2A and Figure 3A As shown, the surface of the adhesive layer 110 may be regularly arranged with protrusions 111. Regular arrangement of protrusions means that the protrusions are arranged on a straight line at fixed intervals. On the other hand, the protrusions 111 may also be arranged in a manner in which the intervals are regularly varied. For example, the intervals between the protrusions in the central portion of the sheet may be shortened, and the intervals between the protrusions in the peripheral portion of the sheet may be lengthened. Furthermore, the protrusions may also be arranged irregularly.

[0113] Figure 3C FIG. 1 is a top view showing another shape of the adhesive layer 110. Figure 3C As shown, stripe-shaped protrusions 111 may be provided on the surface of the adhesive layer 110 . Figure 3C In the embodiment, linear protrusions 111 having a fixed width are arranged at fixed intervals. The width or interval of the linear protrusions 111 may be varied regularly, or the linear protrusions 111 may be arranged irregularly.

[0114] The sheet of this embodiment can be expanded. For example, Figure 2A and Figure 3A The adhesive layer 110 is deformed by expansion. Figure 2B and Figure 3B The adhesive layer 110' is shown. If the adhesive layer 110 is compared with the adhesive layer 110', the pitch P of each protrusion 111 in the adhesive layer 110' is enlarged by expansion, and the number of protrusions 111 holding one component 140 is reduced. Therefore, in the adhesive layer 110', the force of holding the component 140 by the protrusion 111 is reduced compared with the adhesive layer 110.

[0115] From the viewpoint of adjusting the holding force, the pitch P of the protrusions 111 before expansion is preferably greater than 1µm, more preferably greater than 5µm, further preferably greater than 10µm, and further preferably greater than 15µm. On the other hand, from the viewpoint of increasing the contact area between the adhesive layer 110 and the element to improve the holding force, the pitch P is preferably less than 100µm, more preferably less than 75µm, further preferably less than 50µm, further preferably less than 35µm, and further preferably less than 25µm. Here, the pitch P of the protrusions 111 refers to the distance between the center point of an arbitrarily selected protrusion 111 and the center point of another protrusion 111 closest to the protrusion 111. For example, Figure 2A In the case of , the pitch P of the convex portions 111 represents the distance between the center point of the convex portion 111 on the straight line where the convex portions 111 are arranged at a fixed interval and the center point of another convex portion 111 closest to the convex portion 111. In the case where the convex portions 111 are arranged on multiple straight lines, the pitch P represents the distance between the center points of the convex portions on the straight line where the convex portions 111 are arranged at the shortest interval. In this specification, the interval between the convex portions 111 refers to the interval between the centers of the convex portions.

[0116] The specific shape of the convex portion 111 is not particularly limited. For example, the convex portion 111 may also have a pillar shape. As a specific example, the convex portion 111 may have a cylindrical shape or a prism shape. In addition, as described above, the convex portion 111 may extend in a linear shape or in a curved shape such as a wave shape. Moreover, these convex portions 111 may be provided with a slope.

[0117] Figure 4A FIG. 1 is a cross-sectional view of the adhesive layer 110 according to one embodiment, which passes through the protrusion 111 and is perpendicular to the surface of the adhesive layer 110 . Figure 4A The convex portion 111 shown in the figure is provided with an inclination, that is, the front end of the convex portion 111 becomes thinner. Figure 4B As shown, the front end of the protrusion 111 may be a curved surface. According to this structure, the impact when the adhesive layer 110 is used to hold the component is further alleviated, so the adhesive layer 110 can easily hold the component without displacement. On the other hand, the front end of the protrusion may also be a flat surface.

[0118] As another example, the protrusion may be Figure 4B The convex portion 111 may be a hemispherical shape or a part of a sphere. Figure 4C As shown, it is in a T-shape. As another example, the convex portion 111 can be in the shape of a plurality of particle collections, mushroom-shaped, lotus leaf-shaped, or needle-shaped. As yet another example, the surface of the adhesive layer 110 can be rough or fibrous, and such a surface can also be said to have concave-convex.

[0119] From the viewpoint of maintaining the holding force of the element, the width or diameter of each protrusion 111 is preferably 1µm or more, more preferably 2µm or more, further preferably 5µm or more, further preferably 10µm or more. On the other hand, from the viewpoint of improving the ease of peeling of the element, the width or diameter of each protrusion 111 is preferably 100µm or less, more preferably 50µm or less, further preferably 30µm or less, further preferably 20µm or less. Here, the width and diameter of the protrusion 111 refer to the minimum distance and maximum distance (in the surface of the base portion 113) between two parallel lines contacting from both sides of the protrusion 111. Figure 4A Indicated by D in the figure).

[0120] In addition, from the perspective of maintaining the holding force of the element, the area of ​​each protrusion 111 is preferably 10 μm 2 More than 20µm is more preferred 2 More preferably, 30 μm 2 On the other hand, from the perspective of improving the ease of peeling of the element, 2000 μm is preferred. 2 Below, more preferably 1000µm 2 Below, more preferably 500µm 2 Here, the area of ​​the protrusion 111 refers to the area of ​​the portion protruding from the surface of the base portion 113 ( Figure 4A In the case of , it is the area of ​​a circle with diameter D).

[0121] In addition, from the perspective of maintaining the holding force of the element, the total area of ​​the protrusions 111 is preferably 1% or more, more preferably 5% or more, further preferably 10% or more, further preferably 18% or more, further preferably 40% or more relative to the area of ​​the adhesive layer 110. On the other hand, from the perspective of improving the ease of peeling of the element, the total area of ​​the protrusions is preferably 95% or less, more preferably 75% or less, further preferably 60% or less relative to the area of ​​the adhesive layer 110.

[0122] The concavoconvexity of the adhesive layer 110 can also be designed according to the shape of the element held by the sheet. For example, from the viewpoint of maintaining the holding force of the element, the ratio of the bonding area of ​​the adhesive layer 110 to an element relative to the area of ​​an element is preferably 1% or more, more preferably 2% or more, more preferably 3% or more, more preferably 4% or more, more preferably 5% or more, more preferably 7% or more, and more preferably 10% or more. On the other hand, from the viewpoint of improving the ease of peeling of the element, the ratio of the bonding area of ​​the adhesive layer 110 to an element relative to the area of ​​an element is preferably 95% or less, more preferably 70% or less, more preferably 50% or less, and more preferably 30% or less. Figure 4A In the case of, the bonding area is equivalent to the area of ​​a circle with a diameter T. It should be noted that, when the holding position of the element on the sheet is offset, the bonding area may change. In this case, regardless of the position of the processed object, the ratio of the bonding area is preferably within the above range.

[0123] (Peel-off sheet)

[0124] In addition, if Figure 1 As shown, the adhesive sheet of this embodiment may include a release sheet 150 that contacts the adhesive layer 110 and has a concavo-convex surface complementary to the concavo-convex surface of the adhesive layer 110 . Figure 1 In FIG. 1 , for the purpose of illustrating the situation, the adhesive layer 110 and the release sheet 150 are shown separated from each other.

[0125] The release sheet 150 has a release layer 160. The release layer 160 is a layer that is easily releasable from the adhesive layer 110. The release layer 160 may have a concavoconvex surface that is complementary to the concavoconvex surface of the adhesive layer 110. That is, the release layer 160 has a concave portion 161, and the concave portion 161 has a shape that is complementary to the convex portion 111. However, the concave portion 161 does not necessarily have a shape that is complementary to the convex portion 111.

[0126] The release sheet 150 may include a substrate 170 on the surface that is not in contact with the adhesive layer 110. The substrate 170 may be designed in the same manner as the substrate 120, but need not have the same composition or structure as the substrate 120. For example, the material of the substrate 120 is EMAA, and the material of the substrate 170 may be polyethylene terephthalate. In addition, the release sheet 150 may also include a primer layer (not shown) between the release layer 160 and the substrate 170.

[0127] (Other layers)

[0128] The sheet may also have layers other than the substrate and the adhesive layer. For example, a further adhesive layer may be provided on the substrate on the side opposite to the adhesive layer. The sheet may be attached to other objects via this adhesive layer. The type of the further adhesive layer is not particularly limited, and for example, a common adhesive may be used to form the further adhesive layer.

[0129] (Adhesive layer and sheet manufacturing method)

[0130] There is no particular limitation on the method for manufacturing the adhesive layer and the sheet. For example, a sheet having an adhesive layer 110 on a substrate 120 can be made as follows. First, an organic solvent is added to a raw material composition containing the components of the adhesive layer 110 to prepare a solution of the raw material composition. Then, the solution is applied to the substrate 120 to form a coating film and then dried, thereby providing an adhesive layer on the substrate 120. Furthermore, a process of providing a concavo-convex surface on the adhesive layer is performed, thereby forming an adhesive layer 110 having a concavo-convex surface.

[0131] Examples of organic solvents for preparing the solution of the raw material composition include toluene, ethyl acetate, and methyl ethyl ketone. Examples of the method for applying the solution include spin coating, spray coating, rod coating, knife coating, roll coating, roll knife coating, blade coating, die coating, gravure coating, and printing methods (such as screen printing and inkjet).

[0132] There is no particular restriction on the treatment of setting concavoconvex on the surface of the adhesive layer 110. For example, concavoconvex can be set on the surface of the adhesive layer 110 using an embossing method. In the embossing method, a mold having a shape complementary to the concavoconvex to be set can be used on the surface. Specifically, the concavoconvex can be set on the surface of the adhesive layer by heating the adhesive layer while pressing the adhesive layer set on the substrate with a mold. As a more specific method, the adhesive layer can be pressed by a mold, the adhesive layer is heated and maintained for a specified time, and then the adhesive layer is cooled and the mold is removed. When the adhesive layer is heated, for example, the adhesive layer can be heated to a temperature higher than the softening point of the adhesive layer. In addition, the time for maintaining the adhesive layer in a heated state is also not particularly limited, for example, it can be maintained for more than 10 seconds, or it can be maintained for less than 10 minutes. As a specific method for heating the adhesive layer while pressing the adhesive layer with a mold, a method of vacuum laminating the adhesive layer set on the substrate and the mold can be exemplified. It should be noted that, it is also possible to replace the formation of the adhesive layer and the process of the two stages of concavoconvex formation, and utilize the process of one stage that the surface has the concavoconvex adhesive layer to be formed on the substrate. In addition, as a mold, a peeling sheet 150 having a peeling layer 160 with concavoconvex as mentioned above can be used.

[0133] As another method, the adhesive layer 110 having a rough surface can be provided by spraying a solution of the raw material composition. In addition, a filler can be added to the solution of the raw material composition, and the adhesive layer 110 having a rough surface or a fibrous surface can be provided by coating the solution. As another method, the adhesive layer 110 having a concave-convex shape can be directly provided on the substrate 120 by applying the solution of the raw material composition in a desired pattern using a printing method such as an inkjet method.

[0134] (How to use the adhesive sheet)

[0135] The sheet of this embodiment can be used to fix, hold or transfer an object. The type of the object is not particularly limited, and for example, it can be a component described later. For example, the sheet of one embodiment is a sheet for fixing a component, which can be used to fix a component in an adhesive layer. In addition, the sheet of one embodiment is a sheet for transferring a component, which can be used to temporarily hold a component in an adhesive layer and transfer the held component to a desired position. As a specific example, the sheet of this embodiment can be used to transfer a semiconductor chip obtained by dicing to a desired position. Refer to Figure 6 The element peeling method and the transfer method using the sheet of this embodiment are described with reference to the flowchart.

[0136] (S10: Component retention)

[0137] In S10, the adhesive layer of the adhesive sheet of the present embodiment holds the component. It should be noted that the type of component is not particularly limited. The component may be, for example, a semiconductor chip such as an LED chip, a semiconductor chip with a protective film, a semiconductor chip with an adhesive film (DAF), etc. In addition, the component may be a micro-light emitting diode, a sub-millimeter light emitting diode, a power device, a MEMS (Micro Electro Mechanical Systems), or a control chip, or a component thereof. In addition, the component may be a monolithic object such as a wafer, a panel, or a substrate. For example, the component may also have a circuit surface, which is formed with an integrated circuit having circuit elements such as transistors, resistors, and capacitors. In addition, the component is not necessarily limited to a monolithic object, and may also be various wafers or various substrates that are not monolithic.

[0138] In addition, the size of the element is not particularly limited. For example, the size of the element can be preferably 100 μm. 2 More than 500µm 2 More preferably, 1000 μm 2 On the other hand, the size of the element may preferably be 100 mm 2 Below, more preferably 25mm 2 Below, more preferably 1mm 2 the following.

[0139] As wafers, for example, semiconductor wafers such as silicon wafers, silicon carbide (SiC) wafers, compound semiconductor wafers (such as gallium phosphide (GaP) wafers, gallium arsenide (GaAs) wafers, indium phosphide (InP) wafers, and gallium nitride (GaN) wafers) can be cited. The size of the wafer is not particularly limited, but is preferably 6 inches (about 150 mm in diameter) or larger, and more preferably 12 inches (about 300 mm in diameter) or larger. It should be noted that the shape of the wafer is not limited to a circle, and can be, for example, a square or a rectangle.

[0140] As the panel, a fan-out semiconductor package (such as FOWLP or FOPLP) can be exemplified. That is, the processed object can be a semiconductor package before or after singulation in the fan-out semiconductor package manufacturing technology. The size of the panel is not particularly limited, and can be, for example, a square substrate of about 300 to 700 mm.

[0141] Examples of the substrate include a glass substrate, a sapphire substrate, and a compound semiconductor substrate.

[0142] In one embodiment, a component is transferred from a holding substrate to an adhesive sheet, and the adhesive sheet holds the transferred component. For example, a semiconductor wafer can be attached to a wafer substrate, and the semiconductor wafer can be further diced. Then, the component on the wafer substrate obtained by dicing can be brought into close contact with the adhesive layer 110 of the adhesive sheet. Afterwards, by applying external stimuli such as 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 a semiconductor transfer sheet. As another method, the component obtained by dicing the 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.

[0143] In another embodiment, the element attached to the holding substrate can also be separated from the holding substrate by external stimulation. Specifically, the element is relatively far away from the holding substrate. Moreover, the element is relatively close to the adhesive sheet. Then, the element is separated from the holding substrate and captured by the sheet by contacting the adhesive layer 110 of the sheet. The type of external stimulation is not particularly limited, and examples include energy imparting, cooling, expansion of the holding substrate, and physical stimulation (for example, using pins to push the back of the holding substrate). By using one or more of these external stimuli, the binding force between the holding substrate and the element can be reduced, and then the element is separated from the holding substrate. For example, the element can be separated from the holding substrate by irradiation of a laser (laser peeling method). In this embodiment, when the separated element approaches the adhesive layer 110, pressure is generated between the element and the adhesive layer 110. However, by making the surface of the adhesive layer 110 have concave and convex, the pressure generated between the element and the adhesive layer 110 is alleviated, so it is easier to capture the element at the desired position of the sheet.

[0144] In another embodiment, a plurality of components can be formed by dicing the components held on the adhesive layer 110 of the adhesive sheet. For example, a semiconductor wafer is attached to the adhesive layer 110. Then, a plurality of components are formed by dicing the semiconductor wafer on the adhesive layer 110. In this way, the adhesive sheet can also hold the components. This dicing process can be performed before the expansion process (S20) of the adhesive sheet described later.

[0145] (S20: Expansion of adhesive sheet)

[0146] After that, the component held on the adhesive layer 110 of the adhesive sheet is peeled off. By using the adhesive sheet of this embodiment, the component can be peeled off from the adhesive layer 110 with less picking force. On the other hand, in order to peel off the component from the adhesive layer 110 with less picking force, the adhesive sheet holding the component on the adhesive layer 110 can be expanded in the surface direction in S20. By expanding the sheet, the holding force of the component is reduced, so it is easy to peel off the component in the next process.

[0147] The method of expanding the sheet is not particularly limited. For example, the sheet may be expanded in one direction, in two directions, or in multiple directions.

[0148] The expansion rate of the adhesive sheet is also not particularly limited. For example, from the perspective of sufficiently reducing the holding force of the object, the expansion rate of the adhesive sheet in one direction can be greater than 1%, or greater than 5%. In addition, from the perspective of preventing the adhesive sheet from breaking, the expansion rate of the adhesive sheet in one direction can be less than 50%, or less than 20%. From the same perspective, the expansion rate of the adhesive sheet in two mutually orthogonal directions can be greater than 1%, or greater than 5%, and on the other hand, can be less than 50%, or less than 20%.

[0149] As a specific example, the sheet can be expanded by fixing the sheet to a frame and pressing the base against the sheet in the frame. FIG. 5A to FIG. 5B This example will be described. Figure 5A 140a to 140d. Figure 5A As shown, the outer periphery of the 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-shaped member with an opening. In one embodiment, a circular ring frame is used as the frame. By using the ring frame, the sheet can be expanded in all directions.

[0150] Then, the base 310 is brought into contact with the sheet fixed to the frame 320, and further Figure 5B As shown, the frame 320 is displaced (pulled down) toward the side of the base 310, thereby expanding the sheet. It should be noted that the structure of the base 310 is not particularly limited, and for example, it can have a cylindrical shape or a rectangular parallelepiped shape. In addition, the base 310 can also be mesh-shaped or ring-shaped. The frame 320 can be displaced relative to the base 310, for example, at a speed of more than 0.1 mm / sec, or at a speed of more than 1 mm / sec. In this case, from the perspective of sufficiently reducing the holding force of the object, the displacement amount of the frame 320, that is, the pull-down amount, can be, for example, more than 1 mm, or more than 5 mm. On the other hand, from the perspective of suppressing damage to the adhesive sheet, the displacement amount of the frame 320 can be less than 30 mm, or less than 20 mm.

[0151] (S30: Peeling off of components)

[0152] In S30, the element is peeled off from the adhesive layer 110 of the adhesive sheet. In the present embodiment, the element is peeled off from the adhesive layer 110 of the adhesive sheet after expansion in the surface direction. The method of peeling off the element is not particularly limited. For example, the above method can be used as a method of transferring the element adhered to the holding substrate to the adhesive sheet. Specifically, by bringing the substrate or sheet of the transfer destination close to the surface of the element, and using a pin or the like to push the surface of the sheet on the opposite side of the element, the element can be moved to the transfer destination. As another method, specifically, an adsorption member such as a vacuum chuck can be used to peel the element from the adhesive layer 110 of the sheet and move it to the desired position of the transfer destination. By expanding the sheet, the holding force of the adhesive layer 110 decreases. In this case, the element can also be peeled off from the adhesive layer 110 of the sheet without applying a physical stimulus from the opposite side of the adhesive layer 110 of the sheet. Furthermore, the element held on the adhesive sheet can be brought into close contact with the substrate or sheet of the transfer destination, and the adhesion between the adhesive sheet and the element can be reduced by applying external stimulation such as laser. In this way, the element can also be moved from the adhesive sheet to the transfer destination. In this case, by expanding the adhesive sheet, the relative configuration of the multiple elements before the sheet expansion and the relative configuration of the multiple elements in the transfer destination will change.

[0153] According to this process, the adhesive sheet can be used to transfer the component to any transfer destination. In addition, this transfer method can be used to manufacture electronic components or semiconductor devices having the component. It should be noted that the component held by the adhesive sheet can also be processed or processed.

[0154] Example

[0155] The present invention is described in more detail below with reference to examples. However, the present invention is not limited to the following examples. Parts and % in each example are based on the mass of solids unless otherwise specified.

[0156] The following compounds were used in Examples and Comparative Examples.

[0157] <(A) Component: Acrylic Resin>

[0158] As the acrylic resin, an acrylic copolymer (monomer mass ratio: 2-ethylhexyl acrylate / 2-hydroxyethyl acrylate / acrylic acid=92.8 / 7.0 / 0.2, mass average molecular weight (Mw): 1.1 million) was used.

[0159] <Component (B): Energy-Reactive Resin>

[0160] As the energy-reactive resin, tricyclodecane dimethanol diacrylate was used.

[0161] <Component (C): Cross-linking agent>

[0162] As the crosslinking agent, isocyanurate-type polyisocyanate derived from hexamethylene diisocyanate is used.

[0163] <Component (D): Photopolymerization Initiator>

[0164] As a photopolymerization initiator, 2,4,6-trimethylbenzoyldiphenylphosphine oxide was used.

[0165] <Thickness measurement>

[0166] The thickness of each layer and each part was measured at 23° C. using a constant pressure thickness tester manufactured by TECLOCK Co., Ltd. (model: “PG-02J”, standard: in accordance with JIS K6783, Z1702, and Z1709).

[0167] <Pick-up force evaluation>

[0168] The pickup force of the sheet obtained in each example was evaluated as follows: First, the adhesive layer of the sheet obtained in each example was attached to a ring frame (stainless steel, inner diameter 194 mm), and the sheet was cut to match the outer diameter of the ring frame.

[0169] Next, the wafer substrate (mirror silicon wafer, 6 inches, thickness 150µm) is fixed to a dicing tape prepared separately. Then, the wafer substrate is cut into 10mm×10mm squares to obtain a plurality of components (silicon chips, the size of the components is 10mm×10mm×150µm). The plurality of components obtained are adhered to the adhesive layer of the sheet in the central part of the inner side of the above-mentioned ring frame in a manner of mirror-adhering to the adhesive layer. The pasting is performed by laminating at room temperature (23°C). Then, the plurality of components are transferred from the dicing tape to the sheet by peeling off the dicing tape. In this way, a sheet on which a plurality of components are placed and supported by a ring frame is obtained as an evaluation sample. Moreover, for the plurality of components of the obtained evaluation sample, hooks are fixed using an adhesive.

[0170] The evaluation sample with hooks fixed on the component is placed on Figure 5A The stretching device shown. While the component is supported by the base 310 across the sheet, the frame 320 as a ring frame is pressed down at a speed of 1mm / sec. The pressing distance (pull-down amount) is 0mm, 5mm or 10mm. After that, the measuring terminal of the push-pull force gauge (manufactured by Aikoh Engineering Co., Ltd., product name "RX-5") is connected to the hook, and the pick-up force required to pick up the component from the adhesive sheet is measured using the push-pull force gauge.

[0171] (Example 1)

[0172] An adhesive composition was prepared by dissolving 100 solid parts by mass of acrylic resin (A), 25 solid parts by mass of energy-reactive resin (B), 1.25 solid parts by mass of crosslinking agent (C), and 0.75 solid parts by mass of photopolymerization initiator (D) in toluene. The adhesive composition was applied to the release-treated surface of a release sheet (manufactured by Lintec Co., Ltd., trade name: SP-PET382150, formed by laminating a silicone release agent on a polyethylene terephthalate film, thickness 38µm), and the obtained coating was dried at 100°C for 2 minutes to form an adhesive layer with a thickness of 25µm. The shear storage modulus of the obtained adhesive layer was 2.04MPa.

[0173] On the adhesive layer, an EMAA film (ethylene-methacrylic acid copolymer film, acid content 9 mass %, one side surface roughened by embossing, thickness 80 μm) was used as a substrate, and the non-embossed surface of the EMAA film was attached to the adhesive layer.

[0174] After the release sheet was peeled off, the adhesive layer was attached to a stamp mold with a concave shape formed in advance, and vacuum laminated at 60°C for 300 seconds. Next, an ultraviolet irradiator (manufactured by Heraeus) was used at an illumination of 200 mW / cm 2 、Light intensity 800mJ / cm 2 The sheet having a concavo-convex shape on the surface is produced by irradiating with ultraviolet rays. The concavo-convex shape of the adhesive layer of the sheet is similar to Figure 2A Similarly, the columns are arranged in a grid shape. The spacing P between the columns in the sheet is 20 μm. Figure 4A The diameter (T) of the tip of each column is 8µm, and the diameter (D) of the base is 16µm. In addition, the ratio of the area of ​​the adhesive layer and the bonding portion of the element to be captured (i.e., the area of ​​the front end of the protrusion) to the area of ​​the sheet is about 12.6%. Figure 4A The height (H) of each column (convex portion) and the thickness (S) of the base portion are shown in Table 1. In addition, as the above-mentioned stamp mold, a stamp mold having a surface shape complementary to the concavo-convex shape is used.

[0175] The pickup force of the sheet thus obtained was evaluated in the above-mentioned manner. The measured pickup force is shown in Table 1.

[0176] (Examples 2 to 5)

[0177] Sheets were prepared and evaluated in the same manner as in Example 1, except that the adhesive layer was formed so as to have the height (H) of the pillars (projections) and the thickness (S) of the base portion shown in Table 1, respectively.

[0178] (Comparative Examples 1 to 3)

[0179] Sheets were prepared and evaluated in the same manner as in Example 1, except that the adhesive layer was formed to have the height (H) of the pillars (projections) and the thickness (S) of the base portion shown in Table 1. In Comparative Example 1, the adhesive layer had a flat surface and no projections.

[0180]

[0181] According to the comparison between Examples 1 to 5 and Comparative Example 1, it can be seen that by providing the concavoconvex on the surface of the adhesive portion, the effect of reducing the pickup force when the sheet is expanded can be obtained. In addition, according to the comparison between Examples 1 to 5 and Comparative Examples 2 to 3, it can be seen that by making the ratio represented by the thickness of the base portion (S) / the height of the convex portion (H) less than 4.75, the effect of reducing the pickup force can be obtained, and in particular, the pickup force can be further reduced when the sheet is expanded. In particular, according to the comparison between Example 2, Example 3 and Comparative Example 3, the following tendency is generally confirmed: by further reducing the ratio represented by the thickness of the base portion (S) / the height of the convex portion (H), the pickup force will be further reduced.

[0182] The present invention is not limited to the above-described embodiment, and various modifications and changes can be made within the scope of the gist of the invention.

[0183] This application claims priority based on Japanese patent applications No. 2022-151756 filed on September 22, 2022, No. 2022-151757 filed on September 22, 2022, No. 2023-058459 filed on March 31, 2023, No. 2023-058460 filed on March 31, 2023, No. 2023-058462 filed on March 31, 2023, and No. 2023-058463 filed on March 31, 2023, and all the contents recorded therein are incorporated herein by reference.

[0184] Description of Reference Numerals

[0185] 110: adhesive layer;

[0186] 111: convex part;

[0187] 112: concave part;

[0188] 113: basal part;

[0189] 120: base material;

[0190] 140: Components;

[0191] 150: peeling sheet;

[0192] 160: peeling layer;

[0193] 161: concave part;

[0194] 170: substrate;

[0195] P: spacing;

[0196] S: thickness of the base part;

[0197] H: Height of the convex part.

Claims

1. An adhesive sheet comprising a substrate and an adhesive layer having a surface with projections and depressions, characterized in that: The adhesive layer has a base portion consisting of a portion from a concave portion where the thickness of the adhesive layer is the smallest to a surface opposite to the surface having the concave and convex portions in the thickness direction of the adhesive layer, and a convex portion provided on the base portion, and Satisfies the following relationship (1): Relational formula (1): 0.25 In the relational formula (1), S represents the thickness of the base portion, and H represents the height of the convex portion. The base portion has a uniform thickness.

2. The adhesive sheet according to claim 1, characterized in that The adhesive layer has a plurality of protrusions, and the heights of the plurality of protrusions are uniform.

3. The adhesive sheet according to claim 1, characterized in that The height of the protrusion is greater than 1µm and less than 15µm.

4. The adhesive sheet according to claim 1, characterized in that The thickness of the base portion is greater than 1µm and greater than 50µm.

5. The adhesive sheet according to claim 1, characterized in that The base portion is integral with the protrusion.

6. The adhesive sheet according to claim 1, wherein The adhesive layer has a plurality of convex portions which are separated from each other by boundaries determined by concave portions, and a pitch between the plurality of convex portions is not less than 1 μm and not more than 100 μm.

7. The adhesive sheet according to claim 1, wherein The shear storage modulus of the adhesive layer is greater than or equal to 0.001 MPa and less than or equal to 100 MPa.

8. The adhesive sheet according to claim 1, wherein The tensile modulus of the substrate is 2500 MPa or less.

9. The adhesive sheet according to claim 1, wherein The adhesive sheet is a sheet for fixing components.

10. The adhesive sheet according to claim 1, wherein The adhesive sheet is a sheet for transferring components.

11. The adhesive sheet according to claim 1, wherein The adhesive sheet can expand along the surface direction, and the object holding force on the adhesive sheet after expansion is lower than that before expansion.

12. The adhesive sheet according to claim 1, wherein 13. A method for peeling a component from an adhesive sheet, the peeling method comprising: An expansion step of expanding the adhesive sheet according to any one of claims 1 to 12, in which the element is fixed on the adhesive layer, in a surface direction; and The peeling step is to peel the element from the adhesive layer of the adhesive sheet expanded in the surface direction. 14 . The peeling method according to claim 13 , further comprising, before the expansion step, a step of forming a plurality of elements by dicing the element held on the adhesive layer. ​

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