Element transfer sheet

Abstract

The purpose of the present invention is to increase the spacing between elements held by a sheet when the sheet for element transfer, which is provided with an adhesive layer having unevenness on the surface, is expanded. This element transfer sheet is provided with a base material and an adhesive layer having recesses and protrusions on the surface. The tensile stress in a first direction when the substrate is 100% elongated is higher than the tensile stress in a second direction orthogonal to the first direction, the tensile stress in the first direction being 12 MPa or more, and the tensile stress in the second direction being 9 MPa or more.

Description

Technical Field

[0001] The present invention relates to a sheet for transferring a component. Background Art

[0002] There is known a sheet for transferring a component. Such a sheet can be used to temporarily hold an object and transfer it to a desired position. In addition, it is also known to expand the sheet while holding the object.

[0003] For example, Patent Document 1 records that a semiconductor wafer attached to a dicing film is diced, and after dicing, the dicing film is expanded to separate the chips, and each chip is picked up and transferred to another substrate. Patent Document 1 discloses the use of a material with a specific density and a specific component as the material of the dicing film to form an equal gap between the chips during the extension process. In addition, Non-Patent Documents 2 and 3 record that a wafer is attached to an adhesive tape, and the wafer is cut along the predetermined cutting portion by irradiating a laser to the predetermined cutting portion and expanding the adhesive tape.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-014557

[0007] Patent Document 1: Japanese Patent Application Publication No. 2023-013022

[0008] Patent Document 1: Japanese Patent Application Publication No. 2023-013023 Summary of the invention

[0009] Problems to be solved by the invention

[0010] The inventors of the present application have studied the method of providing unevenness on the surface of the adhesive layer of the element transfer sheet. According to this structure, by expanding the sheet, the holding force of the sheet on the element can be reduced, and the element can be easily peeled off from the sheet. On the other hand, it is found that even if the sheet is expanded in a state where the element transfer sheet with unevenness holds the element as described above, the intervals between the elements are sometimes not large.

[0011] An object of the present invention is to increase the interval between components held by a component transfer sheet having an adhesive layer with irregularities on its surface when the sheet is expanded.

[0012] Solutions for solving problems

[0013] The inventors of the present invention have repeatedly conducted research and found that by appropriately adjusting the tensile stress of the substrate of the element transfer sheet, the spacing between the elements held by the sheet will be larger when the sheet is expanded. This can solve the above-mentioned problem. The inventors of the present invention have completed the present invention after further repeated research.

[0014] That is, the present invention relates to the following [1] to [9].

[0015] [1] A sheet for transferring a component, comprising a substrate and an adhesive layer having a surface with projections and depressions,

[0016] When the substrate is 100% elongated, the tensile stress in a first direction is higher than the tensile stress in a second direction orthogonal to the first direction. The tensile stress in the first direction is greater than 12 MPa, and the tensile stress in the second direction is greater than 9 MPa.

[0017] [2] The element transfer sheet according to [1], wherein the tensile stress in the first direction is 40 MPa or less, and the tensile stress in the second direction is 30 MPa or less.

[0018] [3] The element transfer sheet according to any one of [1] to [2], wherein the tensile modulus of the substrate is 2500 MPa or less.

[0019] [4] The element transfer sheet according to any one of [1] to [3], wherein the elongation at break of the substrate is 105% or more.

[0020] [5] The element transfer sheet according to any one of [1] to [4], wherein the substrate is a polyolefin-based film or a vinyl chloride copolymer film.

[0021] [6] The element transfer sheet according to any one of [1] to [5], wherein the adhesive layer has a plurality of convex portions separated from each other by boundaries defined by concave portions, and a pitch between the plurality of convex portions is 1 μm to 100 μm.

[0022] [7] The element transfer sheet according to any one of [1] to [6], wherein the adhesive layer has a plurality of protrusions, and the heights of the plurality of protrusions are uniform.

[0023] [8] An element transfer sheet as described in any one of [1] to [7], wherein after a plurality of elements are formed by dicing a wafer substrate fixed to the adhesive layer, the coefficient of variation of the spacing between the plurality of elements when the element transfer sheet is expanded by 180% in the first direction and the second direction is less than 0.2.

[0024] [9] A sheet for element transfer as described in any one of items [1] to [8], wherein after a plurality of elements are formed by dicing a wafer substrate held on the adhesive layer, an average value of the spacing between the plurality of elements when the sheet for element transfer is expanded by 80 mm in the first direction and the second direction is greater than 1 mm.

[0025] Effects of the Invention

[0026] When a component transfer sheet having an adhesive layer having irregularities on its surface is expanded, the interval between components held by the sheet can be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a cross-sectional view of a sheet according to one embodiment.

[0028] Figure 2A This is a cross-sectional view showing an example of the concavities and convexities of the sheet.

[0029] Figure 2B This is a cross-sectional view showing an example of the concavities and convexities of the sheet.

[0030] Figure 3A This is a plan view showing an example of the concavities and convexities of the sheet.

[0031] Figure 3B This is a plan view showing an example of the concavities and convexities of the sheet.

[0032] Figure 3C This is a plan view showing an example of the concavities and convexities of the sheet.

[0033] Figure 4A This is a cross-sectional view showing an example of the concavities and convexities of the sheet.

[0034] Figure 4B This is a cross-sectional view showing an example of the concavities and convexities of the sheet.

[0035] Figure 4C This is a cross-sectional view showing an example of the concavities and convexities of the sheet.

[0036] Figure 5A This is a diagram for explaining a method of expanding a sheet.

[0037] Figure 5B This is a diagram for explaining a method of expanding a sheet.

[0038] Figure 6 This is a flowchart of a component transfer method according to one embodiment. DETAILED DESCRIPTION

[0039] 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.

[0040] (definition)

[0041] 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.

[0042] In this specification, when more than one lower limit and more than one upper limit 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, 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 records indicate 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.

[0043] (Sheet composition)

[0044] The element transfer sheet of one embodiment of the present invention comprises a substrate 120 and an adhesive layer 110 having a concavoconvex surface. The element transfer sheet is used to temporarily hold an element and transfer it to a transfer destination. For example, the element transfer sheet can be used to receive an element held by another holding substrate, temporarily hold the element, and transfer the element to a desired position of the transfer destination. The substrate 120 can support the adhesive layer 110. Figure 1 , while explaining the structure of such a sheet. In this specification, the element transfer sheet is sometimes simply referred to as a sheet.

[0045] (Base material)

[0046] 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.

[0047] As described later, the sheet material 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 stacking of the sheet material can be easily performed, or the sheet material 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.

[0048] In this embodiment, the tensile stress in the first direction when the substrate 120 is 100% elongated is higher than the tensile stress in the second direction orthogonal to the first direction. Moreover, in this embodiment, the tensile stress in the first direction and the second direction when the substrate 120 is 100% elongated is sufficiently high. The tensile stress in the first direction when the substrate 120 is 100% elongated is 12MPa or more, preferably 14MPa or more, more preferably 18MPa or more, and further preferably 22MPa or more. In addition, the tensile stress in the second direction when the substrate 120 is 100% elongated is 9MPa or more, preferably 12MPa or more, and more preferably 15MPa or more. By using a substrate 120 having such a tensile stress, when the sheet is expanded, the intervals between the multiple elements held by the sheet are easily enlarged. Moreover, by using a substrate 120 having such a tensile stress, when the sheet is expanded, the deviation of the intervals between the multiple elements held by the sheet is easily reduced. By using such a sheet of this embodiment, it is easy to selectively transfer the elements held on the sheet.

[0049] On the other hand, the tensile stress in the first direction when the substrate 120 is 100% elongated is preferably 40 MPa or less, more preferably 30 MPa or less, and further preferably 25 MPa or less. In addition, the tensile stress in the second direction when the substrate 120 is 100% elongated is preferably 30 MPa or less, more preferably 25 MPa or less, and further preferably 20 MPa or less. As described above, by not making the tensile stress of the substrate 120 too high, it is easy to expand the sheet uniformly.

[0050] Furthermore, from the viewpoint of increasing the intervals between the multiple elements held by the sheet when the sheet is expanded and reducing the variation of the intervals, the tensile stress in the first direction when the substrate 120 is 100% elongated is preferably 12 MPa or more, more preferably 14 MPa or more, and on the other hand, it is preferably 40 MPa or less, and more preferably 16 MPa or less. From the same viewpoint, the tensile stress in the second direction when the substrate 120 is 100% elongated is preferably 9 MPa or more, more preferably 10 MPa or more, and further preferably 10.5 MPa or more, and on the other hand, it is preferably 30 MPa or less, more preferably 15 MPa or less, and further preferably 12 MPa or less.

[0051] It should be noted that the first direction may be the direction with the highest tensile stress. Moreover, the first direction may be the MD direction. The MD in the MD direction is the abbreviation of Machine Direction, for example, the MD direction of the substrate refers to the length direction when the substrate is manufactured. On the other hand, the second direction may be the direction with the lowest tensile stress. Moreover, the second direction may be the TD direction. The TD in the TD direction is the abbreviation of Transverse Direction, for example, the TD direction of the substrate refers to the width direction when the substrate is manufactured. As described above, the MD direction and the TD direction are orthogonal to each other. In addition, in this specification, the tensile stress is measured in the manner shown in the embodiments.

[0052] The inventors of the present application have found that by increasing the tensile stress of the substrate 120 in the above manner, the force on the element when the sheet is expanded will increase, resulting in an increase in the spacing between the elements and a decrease in the deviation of the spacing. It should be noted that the tensile stress of the substrate 120 can be adjusted by, for example, selecting a resin material or a combination of resin materials constituting the substrate 120, or mixing additives. In addition, when a copolymer is used as the material of the substrate 120, the tensile stress of the substrate 120 can be adjusted by selecting a combination or ratio of structural units.

[0053] It should be noted that by increasing the tensile stress of the substrate 120 as in the present embodiment, even when there is a difference between the tensile stress in the first direction and the tensile stress in the second direction of the substrate 120, the deviation of the intervals of the plurality of elements held by the sheet can be reduced. In addition, it is believed that the presence of the concave and convex of the adhesive layer 110 on the substrate 120 in the present embodiment also helps to reduce the deviation of the intervals in such a case. From this point of view, the absolute value of the difference between the tensile stress in the first direction and the tensile stress in the second direction when the substrate 120 is 100% elongated can be 2.0 MPa or more, 3.0 MPa or more, or 4.0 MPa or more.

[0054] As specific examples of resin films, there can be cited: polyethylene films such as low-density polyethylene (LDPE) films, linear low-density polyethylene (LLDPE) films, and high-density polyethylene (HDPE) films, 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-(methyl)acrylic acid copolymer films, and ethylene-(methyl)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, etc. 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.

[0055] From the viewpoint of easily expanding the sheet, the substrate 120 is preferably a polyolefin film or a vinyl chloride copolymer film. As a polyolefin film, for example, copolymers containing unsubstituted olefins such as ethylene or propylene as structural units such as polyethylene film, polypropylene film, and ethylene copolymers including ethylene-methacrylic acid copolymer (EMAA) can be exemplified. As a vinyl chloride copolymer film, for example, vinyl chloride-vinylidene chloride copolymer film, vinyl chloride-vinyl acetate copolymer film, and vinyl chloride-ethylene copolymer film can be exemplified. The form of this copolymer is not particularly limited, and can be any of a block copolymer, a random copolymer, an alternating copolymer, and a graft copolymer. It should be noted that other resin components or additives may also be contained in these films.

[0056] 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 10 μm, more preferably greater than 25 μm, and further preferably greater than 40 μm. On the other hand, it is preferably less than 500 μm, more preferably less than 200 μm, further preferably less than 150 μm, further preferably less than 150 μm, further preferably less than 120 μm, and particularly preferably less than 90 μm.

[0057] In order to make the sheet easily expand evenly, 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.

[0058] Similarly, in order to facilitate expansion of the sheet, the elongation at break of the substrate 120 is preferably 105% or more, more preferably 150% or more, and even more preferably 200% or more. In this specification, the elongation at break is measured in accordance with JIS K 7127:1999.

[0059] (Adhesive layer)

[0060] 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.

[0061] (Composition of adhesive layer)

[0062] 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.

[0063] 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 to 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 to 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 contains 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.

[0064] 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.

[0065] From the viewpoint of the morphological stability of the concavo-convex shape on the surface of the adhesive layer, the 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 storage modulus of the adhesive layer 110 is low. From this viewpoint, the 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 storage modulus is measured in accordance with JIS K7244-1:1998. Specifically, the 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 storage modulus of the sample by a torsional shear method at 1 Hz and 23°C.

[0066] 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 can be formed by a thermoplastic resin. In the case of using a thermoplastic resin, the resin is softened by heating, and it is easy to form concave-convex shapes in the adhesive layer 110, and it is easy to maintain the concave-convex shape formed by cooling. As examples of thermoplastic resins, rubber resins, acrylic resins, urethane resins, and olefin resins can be cited. 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.

[0067] 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.

[0068] (Acrylic resin (A))

[0069] 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) acrylate 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.

[0070] 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.

[0071] 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 here is derived can be the value described in the polymer data handbook or the adhesive handbook.

[0072] Examples of the (meth)acrylates 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. 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 hydroxyl group-containing (meth)acrylates; substituted amino group-containing (meth)acrylates such as N-methylaminoethyl (meth)acrylate, and the like. 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.

[0073] 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.

[0074] The monomers constituting the acrylic resin may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio of the monomers may be arbitrarily selected.

[0075] 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, headed by 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).

[0076] 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, further preferably 60 mass % or less.

[0077] (Energy-Reactive Resin (B))

[0078] 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 imparting 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 imparting energy to polymerize the energy-reactive monomer.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] As such energy-reactive resins, polymers into which polymerizable functional groups are introduced can be used. The polymerizable functional groups are functional groups that are crosslinked by the imparting of energy (e.g., irradiation with energy rays). Examples of such polymerizable functional groups include alkenyl groups such as vinyl and allyl, (meth)acryloyl, oxetanyl, and epoxy groups.

[0083] For example, as an energy-reactive resin, a diene rubber composed of a polymer having a polymerizable functional group at the main chain end and / or a 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 a diene rubber, a polymer using butadiene or isoprene as a monomer (i.e., having butene diyl or pentene diyl as a structural unit) can be exemplified. As an energy-reactive resin, polybutadiene resin (PB resin), styrene-butadiene-styrene block copolymer (SBS resin) and styrene-isoprene-styrene block copolymer are preferably used. These resins can be used as ultraviolet reactive resins.

[0084] 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.

[0085] The adhesive layer 110 may include one resin or more than two resins. The adhesive layer 110 of one embodiment may include 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 imparted. In addition, a resin derived from an energy-reactive monomer is a resin obtained by imparting energy to polymerize an energy-reactive monomer. 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.

[0086] 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.

[0087] 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, the film of the mixture of the acrylic resin (A) and the energy-reactive liquid resin or the energy-reactive monomer is formed into a concave-convex shape and then energy is imparted (for example, irradiated with energy rays), so that the energy-reactive liquid resin or the energy-reactive monomer is polymerized, thereby making it easy to maintain the formed concave-convex shape.

[0088] As examples of energy-reactive monomers, bifunctional or polyfunctional compounds into which polymerizable functional groups such as vinyl and allyl groups, (meth)acryloyl groups, oxetane groups, and epoxy groups are introduced can be cited. As preferred examples of energy-reactive monomers, poly(meth)acrylates such as bifunctional (meth)acrylates can be cited. As described above, the adhesive layer 110 can contain an energy-ray-curable resin containing poly(meth)acrylates as structural units. As specific examples of poly(meth)acrylates, cycloalkyl di(meth)acrylates such as tricyclodecane dimethanol diacrylate can be cited.

[0089] 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.

[0090] 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 holding property 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, for example, a resin derived from an energy-ray curable monomer. Here, parts by mass is a mass reference of the solid matter, and the following is also a mass reference unless otherwise specified in advance.

[0091] (Other ingredients of adhesive layer)

[0092] 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.

[0093] 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.

[0094] Among these crosslinking agents, isocyanate crosslinking agents are preferred from the viewpoints of improving cohesion to improve adhesion, ease of acquisition, 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.

[0095] 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.

[0096] 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.

[0097] The photopolymerization initiator (D) initiates a crosslinking reaction by applying energy (e.g., irradiation with energy rays). When the adhesive composition includes an energy-reactive resin (B), the adhesive layer 110 further includes a photopolymerization initiator (D), so that the crosslinking reaction proceeds even when a relatively low energy is applied.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] (Shape of adhesive layer)

[0103] The adhesive layer 110 of this embodiment has a surface with projections and depressions. In one embodiment, the adhesive layer 110 has a plurality of projections on the surface that are separated from each other by depressions. Each of the plurality of projections may be separated by a depression that is continuous across the entire adhesive layer 110 .

[0104] FIG. 2A to FIG. 2B 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. FIG. 2A to FIG. 2B FIG. 1 shows a component 140 held by the protrusion 111 of the adhesive layer 110, and FIG. FIG. 3A to FIG. 3C The element 140 held by the protrusion 111 is omitted.

[0105] 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 center 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.

[0106] Figure 3C FIG. 1 is a top view showing another shape of the adhesive layer 110. Figure 3CAs 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.

[0107] In this embodiment, the sheet is expanded. Figure 2A and Figure 3A The adhesive layer 110 is deformed as shown 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, compared with the adhesive layer 110, the adhesive layer 110' has a lower force for holding the component 140 by the protrusions 111.

[0108] From the viewpoint of adjusting the holding force, the pitch P of the protrusions 111 before expansion is preferably greater than 1 μm, more preferably greater than 5 μm, further preferably greater than 10 μm, and further preferably greater than 15 μm. 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 100 μm, more preferably less than 75 μm, further preferably less than 50 μm, further preferably less than 35 μm, and further preferably less than 25 μm. 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.

[0109] 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.

[0110] 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 4AThe 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.

[0111] like Figure 4A As shown, the surface of the adhesive layer 110 may have a flat concave portion and a convex portion 111 protruding from the concave portion. As described above, the adhesive layer 110 may have a plurality of convex portions 111 spaced apart from each other with their boundaries determined by the concave portion.

[0112] 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.

[0113] From the viewpoint of maintaining the holding force of the element, 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, further preferably 10 μm 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 100 μm or less, more preferably 50 μm or less, further preferably 30 μm or less, further preferably 20 μm or less. Here, the width and diameter of the protrusion 111 refer to the minimum distance and maximum distance ( Figure 4A Indicated by D).

[0114] In addition, from the viewpoint of maintaining the holding force of the element, the area of ​​each protrusion 111 is preferably 10 μm 2 More preferably, 20 μm 2 More preferably, 30 μm 2 On the other hand, from the viewpoint of improving the ease of peeling of the element, 2000 μm is preferred. 2 Below, more preferably 1000 μm 2 Below, more preferably 500 μm 2 Here, the area of ​​the convex portion 111 refers to the area of ​​the portion protruding from the surface of the concave portion ( Figure 4A In the case of , it is the area of ​​a circle with diameter D).

[0115] In one embodiment, from the viewpoint of improving the ease of peeling of the element, the height of each protrusion 111 is preferably 1 μm or more, more preferably 3 μm or more, and further preferably 5 μm or more. On the other hand, from the viewpoint of improving the morphological stability, the height of each protrusion 111 is preferably 20 μm or less, more preferably 15 μm or less, and further preferably 10 μm or less. This can change the holding force of the element. Here, the height of the protrusion 111 is Figure 4A In the figure, H is used to represent the height of the plurality of protrusions of the adhesive layer 110. In addition, in one embodiment, the heights of the plurality of protrusions of the adhesive layer 110 are uniform. In another embodiment, the adhesive layer 110 may have a plurality of first protrusions having a first uniform height and a plurality of second protrusions having different heights. Here, the plurality of second protrusions may also have a second uniform height. For example, the protrusion 111 may also be composed of such a first protrusion and a second protrusion. In yet another embodiment, the adhesive layer 110 may also have a plurality of protrusions of random heights.

[0116] 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.

[0117] 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 one element relative to the area of ​​one element is preferably 1% or more, more preferably 2% or more, further preferably 3% or more, further preferably 4% or more, further preferably 5% or more, further preferably 7% or more, further preferably 10% or more, relative to 100% of the area of ​​one element. 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 one element relative to the area of ​​one element is preferably 95% or less, more preferably 70% or less, further preferably 50% or less, further 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.

[0118] (Peel Sheet)

[0119] In addition, if Figure 1As shown, the element transfer sheet of the present 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 explanation, the adhesive layer 110 and the release sheet 150 are shown separated from each other.

[0120] 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.

[0121] 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.

[0122] (Other layers)

[0123] The sheet material 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 material 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.

[0124] (Characteristics of Component Transfer Sheet)

[0125] From the viewpoint of suppressing positional deviation when holding the element, the adhesion of the element transfer sheet is preferably 1mN / 50mm or more, more preferably 5mN / 50mm or more, further preferably 10mN / 50mm or more, further preferably 15mN / 50mm or more, further preferably 20mN / 50mm or more, and from the viewpoint of peeling the held element from the adhesive layer 110 without damage, the adhesion of the element transfer sheet is preferably 1000mN / 50mm or less, more preferably 500mN / 50mm or less, further preferably 100mN / 50mm or less, further preferably 50mN / 50mm or less. In this specification, the adhesion is measured as follows. That is, after cutting the element transfer sheet into a size of 200mm long × 50mm wide, a laminator is used to press the surface of the adhesive layer onto the mirror surface of the mirror silicon wafer. After the crimping, the samples were left to stand for 1 hour at 23°C and 50% RH (relative humidity) to prepare the adhesive strength test specimens. For the adhesive strength test specimens prepared in the above manner, the adhesive strength was measured in accordance with JIS Z0237:2000 using a tensile tester (manufactured by A&D Co., Ltd., product name "Tensilon (registered trademark)") at 23°C and 50% RH (relative humidity) with a peeling angle of 180° and a tensile speed of 300 mm / min, except for the above measurement conditions.

[0126] (Expansion of Component Transfer Sheet)

[0127] The following is an explanation of the expansion of the element transfer sheet. As described above, the sheet can be expanded in the surface direction while the element transfer sheet is holding the element. The expansion method of the sheet is not particularly limited. For example, the sheet can be expanded in one direction, in two directions, or in multiple directions.

[0128] The expansion rate of the element transfer sheet is not particularly limited. By increasing the amount of expansion, there is a tendency for the spacing between the expanded elements to become larger. For example, the expansion rate of the sheet in one direction may be 50% or more, 100% or more, 150% or more, or 250% or more. In addition, the expansion rate of the sheet in two mutually orthogonal directions may be 50% or more, at least 100% or more, 150% or more, or 250% or more.

[0129] 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 represent the states of the sheet holding elements 140a to 140d. Figure 5AAs 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.

[0130] Then, the base 310 is brought into contact with the sheet material 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. Moreover, as the sheet expands, the intervals between the elements 140a to 140d held by the sheet expand. It should be noted that the structure of the base 310 is not particularly limited, and for example, it may have a cylindrical shape or a rectangular parallelepiped shape. In addition, the base 310 may also be in a mesh or ring shape. The frame 320 may 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, the displacement amount of the frame 320, that is, the pull-down amount, may be, for example, more than 20 mm, or more than 50 mm.

[0131] As described above, according to the present embodiment, if the element transfer sheet is expanded under the state of holding multiple elements, the intervals between the elements will be spaced larger. In one embodiment, multiple elements are formed by cutting the wafer substrate held in the adhesive layer 110. Afterwards, the element transfer sheet is expanded by 80mm in the first and second directions orthogonal to each other, and the average value of the intervals between the multiple elements at this time is preferably more than 2.5mm, more preferably more than 3.0mm, further preferably more than 3.5mm, further preferably more than 4.0mm, and particularly preferably more than 5.0mm. Here, the interval between multiple elements refers to the distance between adjacent elements. In addition, the average value of the intervals between multiple elements is equivalent to the average value associated with the following data group, which includes the intervals associated with the group of all elements adjacent to the first direction, and the intervals associated with the group of all elements adjacent to the second direction.

[0132] As a specific example, the element transfer sheet can be expanded by 80 mm in the first and second directions orthogonal to each other by pulling the frame 320 down by 80 mm relative to the base 310. It should be noted that, for such measurement, a ring frame with an inner diameter of 194 mm can be used as the frame 320. Moreover, a cylindrical member having a diameter slightly smaller than the inner diameter of the frame 320 can be used as the base 310. As described above, the transfer sheet can be expanded by 80 mm in the first and second directions orthogonal to each other by pulling such a frame 320 down by 80 mm relative to the base 310. It should be noted that, in this case, the element transfer sheet can be expanded by about 180% ((194+80+80) / 194=about 180%).

[0133] In addition, according to the present embodiment, if the element transfer sheet is expanded in a state where a plurality of elements are held, the spacing between the elements is more uniform. In one embodiment, a plurality of elements are formed by dicing a wafer substrate held in an adhesive layer 110. Afterwards, the element transfer sheet is expanded by 180% in a first direction and a second direction orthogonal to each other, and the coefficient of variation of the spacing between the plurality of elements at this time is preferably less than 0.20, and more preferably less than 0.15. Here, the coefficient of variation is represented by the mean value / standard deviation. The mean value of the spacing between the plurality of elements is defined as described above. In addition, the standard deviation of the spacing between the plurality of elements is equivalent to the standard deviation associated with the following data group, which includes the spacing associated with the group of all adjacent elements in the first direction, and the spacing associated with the group of all adjacent elements in the second direction. In this measurement, as described above, the frame 320 with an inner diameter of 194 mm can be pulled down 80 mm relative to the base 310 to perform an expansion of about 180%.

[0134] (Method for producing adhesive layer and sheet)

[0135] There is no particular limitation on the manufacturing method of 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.

[0136] 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 (e.g., screen printing and inkjet).

[0137] 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 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 heating the adhesive layer, 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 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 base material. In addition, as mold, it is possible to use the peeling sheet 150 having the peeling layer 160 with concavoconvex as mentioned above.

[0138] 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.

[0139] (How to use the component transfer sheet)

[0140] The sheet of this embodiment can be used for a transfer element. As a specific example, the sheet of this embodiment can be used to transfer a semiconductor chip obtained by dicing to a desired position. Figure 6 The flowchart of FIG. 1 illustrates a component transfer method using the sheet of the present embodiment.

[0141] (S10: Holding of components)

[0142] In S10, the adhesive layer of the element transfer sheet in the present embodiment holds the element. It should be noted that the type of element is not particularly limited. The element 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 element 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 element may be a monolithic object such as a wafer, a panel, or a substrate. For example, the element 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 element is not necessarily limited to a monolithic object, and may also be various wafers or various substrates that are not monolithic.

[0143] 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 preferably 500 μm 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.

[0144] As a wafer, 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, preferably 6 inches (about 150 mm in diameter) or more, and more preferably 12 inches (about 300 mm in diameter) or more. It should be noted that the shape of the wafer is not limited to a circle, for example, it can be a square or a rectangle.

[0145] 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.

[0146] Examples of the substrate include a glass substrate, a sapphire substrate, and a compound semiconductor substrate.

[0147] In one embodiment, a component is transferred from a holding substrate to a sheet for element transfer, and the element transfer 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 sheet for element transfer. Afterwards, by applying external stimulation 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 the sheet for semiconductor transfer. 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 sheet for element transfer using the same method.

[0148] 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 sheet for element transfer. 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 bumps and depressions, the pressure generated between the element and the adhesive layer 110 is alleviated, so that it is easier to capture the element at the desired position of the sheet.

[0149] In another embodiment, a semiconductor wafer is attached to the adhesive layer 110 of the device transfer sheet. Then, devices are formed by dicing the semiconductor wafer on the adhesive layer 110. In this way, the device transfer sheet can also hold the device.

[0150] (S20: Expansion of Component Transfer Sheet)

[0151] In S20, the element transfer sheet is expanded in the surface direction. By expanding the sheet, the interval between the elements becomes larger. Therefore, the handling of the elements in the next process becomes easier. It should be noted that, in one embodiment, by expanding the sheet, the holding force of the element is reduced, so it is easy to peel the element in the next process. The specific expansion method of the sheet is as described above.

[0152] (S30: Peeling off of Components)

[0153] In S30, the element is peeled off from the adhesive layer 110 of the element transfer sheet. In the present embodiment, the element is peeled off from the adhesive layer 110 of the element transfer sheet after expansion in the surface direction. The element peeling method is not particularly limited. For example, the above method can be used as a method for transferring the element attached to the holding substrate to the element transfer sheet. Specifically, by bringing the substrate or sheet of the transfer destination close to the surface of the element, 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 physical stimulation from the opposite side of the adhesive layer 110 of the sheet. Furthermore, the element held on the element transfer sheet can be brought into close contact with the substrate or sheet at the transfer destination, and the adhesion between the element transfer 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 element transfer sheet to the transfer destination. In this case, by expanding the element transfer sheet, the relative arrangement of the plurality of elements before the sheet expansion and the relative arrangement of the plurality of elements at the transfer destination will change.

[0154] According to this process, the component can be transferred to any transfer destination using the component transfer sheet. In addition, this transfer method can be used to manufacture electronic components or semiconductor devices having components. It should be noted that the component held by the component transfer sheet can also be processed or processed.

[0155] Example

[0156] 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.

[0157] The following compounds were used in Examples and Comparative Examples.

[0158] <Component (A): Acrylic Resin>

[0159] 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.

[0160] <Component (B): Energy Reactive Resin>

[0161] As the energy-reactive resin, tricyclodecane dimethanol diacrylate was used.

[0162] <Component (C): Crosslinking Agent>

[0163] As the crosslinking agent, isocyanurate-type polyisocyanate derived from hexamethylene diisocyanate is used.

[0164] <Component (D): Photopolymerization Initiator>

[0165] As a photopolymerization initiator, 2,4,6-trimethylbenzoyldiphenylphosphine oxide was used.

[0166] <Evaluation of tensile stress of substrate>

[0167] The tensile stress of the substrate used in each example is evaluated as follows. As a test sample, a substrate cut into 150 mm in the MD direction × 15 mm in the TD direction is used. For this test sample, the tensile stress in an environment of 23°C and 50% RH (relative humidity) is measured in accordance with JIS K 7161-1: 2014 and JIS K7127: 1999. In the measurement, a tensile tester (manufactured by Shimadzu Corporation, product name "Autograph (registered trademark) AG-IS 500N") is used. Specifically, after setting the distance between the chucks to 100 mm, the above test sample is subjected to a tensile test at a speed of 200 mm / min to measure the tensile stress (MPa) in the MD direction when the support is 100% elongated. In addition, the same test is performed by using a substrate cut into 150 mm in the TD direction × 15 mm in the MD direction as a test sample, and the tensile stress (MPa) in the TD direction when the support is 100% elongated is measured.

[0168] <Expansion test>

[0169] The expansion test of the sheet obtained in each example was conducted 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.

[0170] Next, fix the wafer substrate (mirror silicon wafer, 6 inches, thickness 150μm) to a dicing tape prepared separately. Then, cut the wafer substrate 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 pasted to the adhesive layer of the sheet in the central part of the inner side of the above-mentioned annular frame in the form of mirror-pasted adhesive layers. The pasting is performed by lamination at room temperature (23°C). Then, the dicing tape is peeled off to transfer the plurality of components from the dicing tape to the sheet. In this way, a sheet carrying a plurality of components and supported by an annular frame is obtained as an evaluation sample.

[0171] The obtained evaluation samples were placed in Figure 5A The stretching device shown. While the element is supported by the base 310 across the sheet, the frame 320 serving as an annular frame is pressed down at a speed of 1mm / sec and a pull-down amount of 80mm. After pressing down, the intervals (longitudinal and transverse) of each chip are measured using a digital microscope. Here, the interval of each chip refers to the distance between adjacent chips. Moreover, based on the intervals of each chip measured in this way, the average value and coefficient of variation of the intervals of each chip are calculated. The average value and coefficient of variation of the intervals of multiple chips are equivalent to the average value and coefficient of variation associated with the following data group, which includes the intervals associated with the group of all chips adjacent in the first direction, and the intervals associated with the group of all chips adjacent in the second direction.

[0172] (Example 1)

[0173] The adhesive composition is 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 is 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, with a thickness of 38 μm), and the obtained coating is dried at 100° C. for 2 minutes to form an adhesive layer with a thickness of 25 μm. The storage modulus of the obtained adhesive layer is 2.04 MPa.

[0174] On this adhesive layer, a PVC film (containing 35 parts by mass of di(2-ethylhexyl)phthalate as a plasticizer relative to 100 parts by mass of the vinyl chloride copolymer, with a thickness of 80 μm) as a substrate was bonded. The tensile modulus and elongation at break (TD direction and MD direction) of the substrate are shown in FIG. Figure 1 .

[0175] After the release sheet was peeled off, the adhesive layer was attached to a stamp mold having 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 with a concavo-convex shape on the surface is produced by irradiating with ultraviolet rays. Figure 2A Similarly, the columns are arranged in a lattice shape. The pitch P between the columns in the sheet is 20 μm. Figure 4AThe height (H) of each column shown is 8 μm, the diameter (T) of the front end is 8 μm, and the diameter (D) of the base is 16 μm. 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 surface of the convex portion) to the area of ​​the sheet is about 12.6%. It should be noted that as the above-mentioned stamp mold, a stamp mold having a surface shape complementary to this concave and convex shape is used.

[0176] The sheet thus obtained was subjected to an expansion test in the above manner. The average values ​​and coefficients of variation of the obtained chip spacing are shown in Table 1. In addition, Table 1 further shows the evaluation results of the expansion test evaluated based on the size of the chip spacing and the deviation of the chip spacing. In Table 1, "A" indicates that the evaluation result is good, and "F" indicates that the evaluation result is poor.

[0177] (Example 2)

[0178] A sheet was prepared in the same manner as in Example 1, except that an EMAA film (ethylene-methacrylic acid copolymer film, acid content 9 mass %, one side surface roughened by embossing, thickness 80 μm) was used as the substrate and the non-embossed surface of the EMAA film was attached to the adhesive layer. The adhesive force of the sheet of Example 2 was 23.5 mN / 50 mm.

[0179] (Example 3)

[0180] A sheet was prepared in the same manner as in Example 1 except that a PO film (ethylene-block-propylene copolymer, thickness 110 μm) was used as the substrate.

[0181] (Comparative Example 1)

[0182] A sheet was prepared in the same manner as in Example 1 except that an LDPE film (amorphous low-density polyethylene, thickness 70 μm) was used as the substrate.

[0183] [Table 1]

[0184]

[0185] According to the comparison between Examples 1 to 3 and Comparative Example 1, when the tensile stress in the first direction (e.g., MD direction) is 12 MPa or more and the tensile stress in the second direction (e.g., TD direction) is 9 MPa or more when the substrate is 100% elongated, the chip spacing becomes larger and the deviation of the chip spacing becomes smaller, and a good evaluation result can be obtained. In particular, when the tensile stress in the first direction is 18 MPa or more and the tensile stress in the second direction is 12 MPa or more as in Example 1, the chip spacing becomes larger and the deviation of the chip spacing becomes particularly small, and a particularly good evaluation result is obtained. In addition, when the tensile stress in the first direction is 12 MPa or more and 16 MPa or less and the tensile stress in the second direction is 9 MPa or more and 12 MPa or less as in Example 3, the chip spacing becomes particularly large and the deviation of the chip spacing becomes smaller, and a particularly good evaluation result is obtained.

[0186] 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.

[0187] 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.

[0188] Description of Reference Numerals

[0189] 110: adhesive layer;

[0190] 120: base material;

[0191] 111: convex part;

[0192] 140: Components;

[0193] 150: peeling sheet;

[0194] 160: peeling layer;

[0195] 161: concave part;

[0196] 170: substrate;

[0197] P: Spacing.

Claims

1. A sheet for transferring an element, comprising a substrate and an adhesive layer having a concavo-convex surface, When the substrate is 100% elongated, the tensile stress in a first direction is higher than the tensile stress in a second direction orthogonal to the first direction. The tensile stress in the first direction is greater than 12 MPa, and the tensile stress in the second direction is greater than 9 MPa. 2 . The element transfer sheet according to claim 1 , wherein the tensile stress in the first direction is 40 MPa or less, and the tensile stress in the second direction is 30 MPa or less. 3 . The element transfer sheet according to claim 1 , wherein the tensile modulus of the base material is 2500 MPa or less. 4 . The element transfer sheet according to claim 1 , wherein the base material has an elongation at break of 105% or more. 5 . The element transfer sheet according to claim 1 , wherein the base material is a polyolefin-based film or a vinyl chloride copolymer film. 6 . The element transfer sheet according to claim 1 , wherein the adhesive layer has a plurality of convex portions which are separated from each other by boundaries defined by concave portions, and a pitch between the plurality of convex portions is 1 μm or more and 100 μm or less. 7 . The element transfer sheet according to claim 1 , wherein the adhesive layer has a plurality of convex portions, and the plurality of convex portions have uniform heights.

8. The element transfer sheet according to claim 1, wherein after a plurality of elements are formed by dicing a wafer substrate held on the adhesive layer, a coefficient of variation of the spacing between the plurality of elements when the element transfer sheet is expanded 180% in the first direction and the second direction is less than 0.

2.

9. The element transfer sheet according to claim 1, wherein after a plurality of elements are formed by dicing a wafer substrate held on the adhesive layer, an average value of the intervals between the plurality of elements when the element transfer sheet is expanded by 80 mm in the first direction and the second direction is greater than 1 mm.

Images