Kit for forming laminate body including light-to-heat conversion layer, laminate body including light-to-heat conversion layer, and manufacturing method thereof

Abstract

To provide an adhesive kit for forming a laminate body including a light- to-heat conversion layer, which can be rapidly cured at room temperature or by relatively gentle heating without requiring UV irradiation, and which allows long-term storage at room temperature and a long usable life.SOLUTION: Provided is a kit for forming a laminate body including a light-to-heat conversion layer. The kit comprises: a free radical polymerizable liquid adhesive containing at least one free radical polymerizable compound and at least one polyvalent metal compound for polymerizing the at least one free radical polymerizable compound; a light-to-heat conversion layer ink composition containing a thermally decomposable light absorbing agent and a binder or precursor thereof; and a curing accelerator containing a β-dicarbonyl compound or salt thereof.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a kit for forming a laminate including a photothermal conversion layer, the laminate including the photothermal conversion layer, and a method for manufacturing the same. The present disclosure also relates to a method for manufacturing a thinned substrate and a method for manufacturing a semiconductor substrate laminate using the laminate.

Background Art

[0002] In the semiconductor industry, in order to meet the requirements for thinning of packages and high density by chip stacking technology, thinning of semiconductor wafers by so-called back grinding, which grinds the surface opposite to the patterned surface, is being promoted. The conventional technology in which the wafer is supported only by a protective tape during the back grinding and transfer processes is insufficient to meet the requirements of various newly proposed manufacturing processes. Therefore, during back grinding and, if necessary, subsequent processes, the semiconductor wafer is supported via an adhesive on a hard transparent support such as a glass substrate having a light-to-heat conversion (LTHC) layer, and finally, the photothermal conversion layer is destroyed by laser scanning to separate the semiconductor wafer or a semiconductor chip obtained by dicing the semiconductor wafer from the support without stress.

[0003] Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-064040) describes "a laminate including a substrate to be ground, a bonding layer in contact with the substrate to be ground, a photothermal conversion layer including a light absorber and a thermally decomposable resin, and a light-transmissive support, provided that the photothermal conversion layer decomposes when irradiated with radiant energy after grinding the surface of the substrate to be ground on the side opposite to the bonding layer, and separates the ground substrate and the light-transmissive support."

[0004] Patent Document 2 (Japanese Patent Application Laid-Open No. 2013-534721) describes "a laminate including a substrate, a bonding layer adjacent to the substrate, a photothermal conversion layer adjacent to the bonding layer and including a metal absorption layer, and a light-transmissive support adjacent to the photothermal conversion layer."

[0005] Patent Document 3 (Japanese Patent Application Laid-Open No. 2019-189868) describes a method for temporarily bonding a workpiece, comprising: a bonding step of forming a bonding layer on the surface of at least one substrate and / or at least one workpiece; an adhesion step of adhering and bonding the substrate and the workpiece with the bonding layer; a processing step of processing the workpiece; and a peeling step of irradiating the bonding layer with a laser to separate the workpiece from the substrate, wherein the bonding layer is composed of an adhesive containing a polymer and a light-absorbing substance, the solid content of the adhesive contains 50 wt% to 98 wt% of the polymer, the solid content of the adhesive contains 2 wt% to 50 wt% of the light-absorbing substance, the polymer is a polyimide or an (amic acid / imide) copolymer, the backbone of the polymer contains 5 wt% to 45 wt% of hydroxyl-containing units, further contains 5 wt% to 40 wt% of aliphatic ether-containing units or siloxane-containing units, and the cyclization rate of the polymer is 90% or more.

[0006] Patent Document 4 (Japanese Patent Application Laid-Open No. 2015-199794) describes a peeling method, comprising: irradiating an energy ray from the support side to a laminate comprising a support that transmits light and an adherend fixed to the support via an adhesive to separate the support and the adherend, wherein the adhesive contains a condensation resin and carbon particles containing boron, and the adherend contains at least one of an inorganic material and an organic material.

[0007] Patent Document 5 (Japanese Patent Application Laid-Open No. 2012-052031) describes a method for processing a processed layer, comprising in this order: (1) a step of forming an adhesive layer containing a polymer (A) and a photo radical generator (B) on a support, wherein the content of the polymerizable compound in 100 wt% of the adhesive layer is 10 wt% or less; (2) a step of forming a processed layer on the adhesive layer; (3) a step of processing the processed layer; (4) a step of irradiating light from the support side to the adhesive layer; and (5) a step of peeling the processed layer after processing from the support.

[0008] Patent Document 6 (Japanese Patent Application Laid-Open No. 2017-011279) describes "a method for manufacturing a semiconductor device, including a step of separating a wafer from a support of the wafer by swelling, without dissolving, with a solvent, an adhesive layer formed using an adhesive composition containing, as a constituent unit of a main chain, an elastomer containing a styrene unit, the content of the styrene unit being more than 50% by weight and 90% by weight or less, and the weight average molecular weight being 10,000 or more and 200,000 or less."

[0009] Patent Document 7 (Japanese Patent Application Laid-Open No. 2019-119762) describes "an adhesive composition containing an elastomer having a constituent unit (u1) represented by the following general formula (u1-1). [Chemical formula] [In the general formula (u1-1), R α1 represents an alkyl group having 1 to 5 carbon atoms or a hydrogen atom. R 01 represents a group containing an alicyclic group. R 02 represents a halogen atom, an alkyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom, an aryl group having 6 to 12 carbon atoms which may be substituted with a halogen atom, a cyano group, a nitro group, a hydroxyl group, a carboxyl group, a group represented by -OR, and a group represented by -COOR (wherein R is an alkyl group which may be substituted with a halogen atom having 1 to 8 carbon atoms).), and is a group not corresponding to R 01 . m is a natural number of 1 to 5, and n1 is an integer of 0 or more. However, the sum of m and n1 does not exceed 5.]" [Prior Art Documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-064040 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-534721 [Patent Document 3] Japanese Patent Application Laid-Open No. 2019-189868 [Patent Document 4] Japanese Patent Application Laid-Open No. 2015-199794 [Patent Document 5] Japanese Patent Application Laid-Open No. 2012-052031 [Patent Document 6] Japanese Patent Application Laid-Open No. 2017-011279 [Patent Document 7] Japanese Patent Application Laid-Open No. 2019-119762 [Summary of the Invention] [Problems to be Solved by the Invention]

[0011] A UV-curable adhesive used for temporarily fixing a semiconductor wafer on a support having a photothermal conversion layer is applied in a liquid state and cured by UV irradiation. The rapid curing by UV irradiation is a great advantage of using a UV-curable adhesive, but it may require a special device compatible with UV irradiation and the design of a manufacturing line, and the support is required to be transparent to ultraviolet light. In addition, when introducing temporary fixing using a UV-curable adhesive, a bonding device designed for a thermosetting material used in other processes of semiconductor manufacturing may not be available.

[0012] When temporarily fixing a semiconductor wafer using a thermosetting adhesive, it may be necessary to heat a laminate including the semiconductor wafer, the thermosetting adhesive, and the support at a high temperature (e.g., about 200°C) for a relatively long time (e.g., about 60 minutes). Storage of a one-component thermosetting adhesive containing an adhesive component and a curing agent may require refrigeration or freezing. In addition, since a one-component thermosetting adhesive generally has a limited pot life, if the adhesive stays in the device for a long time due to malfunction or failure of the device after loading the adhesive into the device, gelation may occur and the operation of the device may be hindered.

[0013] The present disclosure provides an adhesive kit for forming a laminate including a photothermal conversion layer, which enables rapid curing without requiring UV irradiation at room temperature or with relatively gentle heating, and enables long-term storage at room temperature and a long pot life.

Means for Solving the Problem

[0014] According to one embodiment of the present disclosure, a free-radical polymerizable liquid adhesive comprising at least one free-radical polymerizable compound and at least one polyvalent metal compound for polymerizing the at least one free-radical polymerizable compound; a photothermal conversion layer ink composition comprising a light absorber having thermal decomposability and a binder or a precursor thereof; a β-dicarbonyl compound represented by the following formula or a salt thereof

Chemical formula

Chemical formula

Chemical formula

[0015] According to another embodiment of the present disclosure, A free-radical polymerizable liquid adhesive comprising at least one free-radical polymerizable compound and at least one polyvalent metal compound for polymerizing the at least one free-radical polymerizable compound, A light absorber having thermal decomposability, a binder or a precursor thereof, and a β-dicarbonyl compound represented by the following formula or a salt thereof

Chemical formula

Chemical formula

Chemical formula

[0016] According to yet another embodiment of the present disclosure, A light-transmissive support, A photothermal conversion layer disposed on the light-transmissive support, A curing acceleration layer disposed on the photothermal conversion layer, A laminate comprising, The photothermal conversion layer contains a photoabsorbent having pyrolyzability and a binder. The curing acceleration layer contains a β-dicarbonyl compound represented by the following formula or a salt thereof

Chemical formula

Chemical formula

Chemical formula

[0017] According to still another embodiment of the present disclosure, a light-transmissive support, a photothermal conversion layer disposed on the light-transmissive support, A laminate comprising: The photothermal conversion layer contains a photoabsorbent having pyrolyzability, a binder, and a β-dicarbonyl compound represented by the following formula or a salt thereof

Chemical formula

[0018] According to yet another embodiment of the present disclosure, applying a free-radical polymerizable liquid adhesive to a substrate to form a pre-bonding layer on the substrate, applying a photo-thermal conversion layer ink composition to a light-transmissive support to form a photo-thermal conversion layer on the light-transmissive support, applying a curing accelerator on the photo-thermal conversion layer to form a curing accelerator layer on the photo-thermal conversion layer, and bonding the substrate and the light-transmissive support so that the pre-bonding layer and the curing accelerator layer are in contact with each other, and at least partially curing the pre-bonding layer, thereby forming a bonding layer, A method for manufacturing a laminate including a photo-thermal conversion layer, including wherein the free-radical polymerizable liquid adhesive includes at least one free-radical polymerizable compound and at least one polyvalent metal compound for polymerizing the at least one free-radical polymerizable compound, The above-described photothermal conversion layer ink composition contains a heat-decomposable light absorber and a binder or a precursor thereof. The above-described curing accelerator is a β-dicarbonyl compound represented by the following formula or a salt thereof.

Chemical formula

Chemical formula

Chemical formula

[0019] According to still another embodiment of the present disclosure, applying a free-radical polymerizable liquid adhesive to a substrate to form a bonding precursor layer on the substrate, applying a photothermal conversion layer ink composition to a light-transmissive support to form a photothermal conversion layer on the light-transmissive support, and bonding the substrate and the light-transmissive support so that the bonding precursor layer and the photothermal conversion layer are in contact with each other, and at least partially curing the bonding precursor layer to thereby form a bonding layer. A method for manufacturing a laminate including a photothermal conversion layer, comprising: The free radical polymerizable liquid adhesive includes at least one free radical polymerizable compound and at least one polyvalent metal compound for polymerizing the at least one free radical polymerizable compound; The photothermal conversion layer ink composition includes a photothermal absorber having thermal decomposability, a binder or a precursor thereof, and a β-dicarbonyl compound represented by the following formula or a salt thereof

Chemical formula

Chemical formula

Chemical formula

[0020] According to still another embodiment of the present disclosure, preparing a laminate obtained by the above method, wherein the substrate is a substrate to be ground, grinding the substrate to be ground until the substrate to be ground reaches a desired thickness, Irradiating radiant energy through the light-transmissive support onto the photothermal conversion layer to decompose the photothermal conversion layer, thereby separating the ground substrate having the bonding layer from the light-transmissive support, and optionally removing the bonding layer from the ground substrate A method for manufacturing a thinned substrate is provided, which includes the above steps.

[0021] According to still another embodiment of the present disclosure, preparing a laminate obtained by the above method, wherein the substrate is a semiconductor substrate, and the semiconductor substrate has an insulating layer disposed on the surface of the semiconductor substrate on the side opposite to the bonding layer, and one or more conductive connection portions penetrating the insulating layer and electrically connected to the semiconductor substrate, preparing a second semiconductor substrate having a second insulating layer disposed on the surface of the second semiconductor substrate and one or more second conductive connection portions penetrating the second insulating layer and electrically connected to the second semiconductor substrate, opposing the conductive connection portion of the semiconductor substrate and the second conductive connection portion of the second semiconductor substrate, and thermocompression bonding the semiconductor substrate and the second semiconductor substrate, thereby forming a semiconductor substrate laminate in which the conductive connection portion and the second conductive connection portion are joined and the insulating layer and the second insulating layer are joined, irradiating radiant energy through the light-transmissive support onto the photothermal conversion layer to decompose the photothermal conversion layer, thereby separating the semiconductor substrate laminate having the bonding layer from the light-transmissive support, and optionally removing the bonding layer from the surface of the semiconductor substrate laminate A method for manufacturing a semiconductor substrate laminate is provided, which includes the above steps.

Advantages of the Invention

[0022] According to the present disclosure, an adhesive kit capable of rapid curing without requiring UV irradiation at room temperature or with relatively gentle heating to form a laminate including a photothermal conversion layer, enabling long-term storage at room temperature and a long pot life, can be provided. A laminate including a photothermal conversion layer formed using the adhesive kit can be used in various processes in semiconductor device manufacturing, such as thinning of a substrate, formation of a semiconductor substrate laminate, and the like.

[0023] The above description should not be regarded as disclosing all embodiments of the present invention and all advantages related to the present invention.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0025] Hereinafter, for the purpose of exemplifying representative embodiments of the present invention, a more detailed description will be given with reference to the drawings as necessary, but the present invention is not limited to these embodiments.

[0026] In the present disclosure, “(meth)acrylic” refers to acrylic or methacrylic, and “(meth)acrylate” refers to acrylate or methacrylate.

[0027] In the present disclosure, "hydrocarbyl" refers to a monovalent group derived from a hydrocarbon. Examples of hydrocarbyl include methyl, phenyl, and methylcyclohexyl.

[0028] In the present disclosure, "hydrocarbylene" refers to a divalent group derived from a hydrocarbon. Examples of hydrocarbylene include methylene, phenylene, and 1,3 - propane - diyl.

[0029] In the present disclosure, the "free - radical polymerizable liquid adhesive" is also simply referred to as the "liquid adhesive".

[0030] In the present disclosure, the "solid content" refers to the total mass of the components excluding the solvent from the composition.

[0031] A kit for forming a laminate including a photothermal conversion layer of the first embodiment includes a free - radical polymerizable liquid adhesive including at least one free - radical polymerizable compound and at least one polyvalent metal compound for polymerizing the at least one free - radical polymerizable compound; a photothermal conversion layer ink composition including a photoabsorbent having thermal decomposability, and a binder or a precursor thereof; and a curing accelerator including a β - dicarbonyl compound or a salt thereof.

[0032] A kit for forming a laminate including a photothermal conversion layer of the second embodiment includes a free - radical polymerizable liquid adhesive including at least one free - radical polymerizable compound and at least one polyvalent metal compound for polymerizing the at least one free - radical polymerizable compound; and a photothermal conversion layer ink composition including a photoabsorbent having thermal decomposability, a binder or a precursor thereof, and a β - dicarbonyl compound or a salt thereof.

[0033] The β - dicarbonyl compounds of the first embodiment and the second embodiment are represented by the following formula.

Chemical formula

Chem.

Chem.

[0034] In the first embodiment, the polyvalent metal compound is contained in the liquid adhesive, and the β-dicarbonyl compound or its salt is contained in the curing accelerator. The curing accelerator is applied onto the photothermal conversion layer formed using the photothermal conversion layer ink composition to form a curing accelerator layer. By bringing the liquid adhesive containing the polyvalent metal compound into contact with the curing accelerator layer containing the β-dicarbonyl compound or its salt, a radical reaction proceeds and the liquid adhesive cures. In the first embodiment, since the β-dicarbonyl compound or its salt is present in the curing accelerator layer, that is, the β-dicarbonyl compound or its salt is unevenly present on the photothermal conversion layer, the radical reaction can be effectively advanced with a small amount of the β-dicarbonyl compound.

[0035] In the second embodiment, the polyvalent metal compound is included in the liquid adhesive, and the β-dicarbonyl compound or its salt is included in the photo-thermal conversion layer ink composition. By bringing the liquid adhesive containing the polyvalent metal compound into contact with the photo-thermal conversion layer containing the β-dicarbonyl compound or its salt, a radical reaction proceeds and the liquid adhesive cures. In the second embodiment, since the radical reaction can proceed without providing a separate curing acceleration layer, the manufacturing process of the laminate can be simplified.

[0036] In the present disclosure, a radical reaction known as Bredereck Chemistry represented by the following formula is utilized. In the presence of a polyvalent metal compound, the β-dicarbonyl compound or its salt reacts with oxygen (O2) to generate an active species having an oxyradical, and this active species causes the radical reaction to proceed. By coexisting halogen ions as necessary, uniform curing in the depth direction is promoted. That is, the initiator for Bredereck Chemistry includes the β-dicarbonyl compound or its salt, the polyvalent metal compound, and halogen ions as necessary. The radical reaction using Bredereck Chemistry proceeds rapidly even at room temperature and is further promoted, for example, when heated to 100°C. Although oxygen (O2) is required for the radical reaction to proceed in Bredereck Chemistry, the inventor has unexpectedly found that in the applications envisioned in the present disclosure, such as the temporary fixation of a semiconductor wafer to a support, the radical reaction proceeds sufficiently with the dissolved oxygen contained in the adhesive. Furthermore, the inventor has found that oxygen inhibition, which is a problem in UV curing or thermal curing using peroxides, that is, poor curing at the end of the bonding region in contact with the air atmosphere, can also be prevented or suppressed by using a radical reaction system based on Bredereck Chemistry.

[0037]

Chemical formula

[0038] In the present disclosure, the β-dicarbonyl compound or its salt that is converted into an active species for promoting a radical reaction is included in the curing acceleration layer on the photothermal conversion layer or in the photothermal conversion layer, and the polyvalent metal compound that promotes the generation of the active species is included in the liquid adhesive. The β-dicarbonyl compound or its salt and the polyvalent metal compound are thermally stable by themselves. As long as the curing acceleration layer or the photothermal conversion layer and the adhesive are stored separately, the radical reaction of the liquid adhesive does not occur, so these layers or components can be stored at room temperature for a long period of time and a long pot life can be ensured.

[0039] The free-radical polymerizable liquid adhesives of the first embodiment and the second embodiment include at least one free-radical polymerizable compound and at least one polyvalent metal compound for polymerizing the at least one free-radical polymerizable compound.

[0040] Examples of the at least one free-radical polymerizable compound include (meth)acrylates, (meth)acrylamides, other vinyl compounds, and combinations of two or more of these. The free-radical polymerizable compound may include an ethylenically unsaturated compound having one or more (for example, one, two, three, four, or more) free-radical polymerizable groups.

[0041] The at least one free-radical polymerizable compound preferably includes a free-radical polymerizable (meth)acrylate oligomer. By using such a (meth)acrylate oligomer, the time required for curing the liquid adhesive can be shortened. Examples of the (meth)acrylate oligomer include oligomers having a free-radical polymerizable vinyl group such as urethane acrylate, epoxy acrylate, or polyester acrylate.

[0042] The content of the (meth)acrylate oligomer in the liquid adhesive is not particularly limited, but can be, for example, about 20% by mass or more and about 80% by mass or less based on the total mass of the free-radical polymerizable compounds.

[0043] At least one free-radical polymerizable compound preferably contains a free-radical polymerizable polyfunctional (meth)acrylate. Examples of polyfunctional (meth)acrylates include 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol di(meth)acrylate, ditrimethylolpropane di(meth)acrylate, bisphenol A di(meth)acrylate, ethoxylated bisphenol A diacrylate, propoxylated bisphenol A diacrylate, 2-[5-ethyl-5-[(acryloyloxy)methyl]-1,3-dioxan-2-yl]-2,2-dimethylethyl acrylate, tricyclo[5.2.1.0 2,6 decane dimethanol di(meth)acrylate and other difunctional (meth)acrylates; pentaerythritol tri(meth)acrylate, isocyanuric acid EO-modified tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate and other trifunctional (meth)acrylates; dipentaerythritol tetra(meth)acrylate; and dipentaerythritol penta(meth)acrylate. When the number of polymerizable functional groups increases, even a small amount of addition is likely to affect the storage modulus of the adhesive after curing. Therefore, difunctional (meth)acrylates and trifunctional (meth)acrylates are preferred, and difunctional (meth)acrylates are more preferred. Difunctional (meth)acrylates can be used, for example, for the purpose of introducing a crosslinked structure into the cured product to adjust the storage modulus in its rubbery plateau region.

[0044] The content of polyfunctional (meth)acrylate in the liquid adhesive is not particularly limited. For example, it can be about 70% by mass or more and about 100% by mass or less based on the total mass of the free-radical polymerizable compounds.

[0045] At least one free-radically polymerizable compound may contain a monofunctional (meth)acrylic monomer. The monofunctional (meth)acrylic monomer can adjust the viscosity of the liquid adhesive to an appropriate range according to the application. Examples of the monofunctional (meth)acrylic monomer include alkyl (meth)acrylates such as butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate; alicyclic (meth)acrylates such as cyclohexyl (meth)acrylate; aromatic (meth)acrylates such as phenyl (meth)acrylate, phenylethyl (meth)acrylate; and monofunctional (meth)acrylates having polar functional groups such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl phthalate, 2-(meth)acryloyloxyethyl hexahydrophthalate, 2-(meth)acryloyloxyethyl succinic acid, (meth)acryloyloxypropyltrimethoxysilane.

[0046] The content of the monofunctional (meth)acrylic monomer in the liquid adhesive is not particularly limited, and for example, it can be about 0% by mass or more and about 30% by mass or less based on the total mass of the free-radically polymerizable compounds.

[0047] As at least one polyvalent metal compound for polymerizing at least one free-radically polymerizable compound, a salt, complex, or chelate of an organic anion (for example, a conjugate base of an organic acid having 1 to 18 carbon atoms) and a polyvalent metal ion can be used.

[0048] At least one polyvalent metal compound preferably contains at least one selected from the group consisting of copper (II), vanadium (IV), iron (II), iron (III), cobalt (II), cobalt (III), manganese (II), and manganese (III). These polyvalent metal compounds can more effectively promote radical reactions.

[0049] Examples of polyvalent metal compounds include copper (II) compounds such as copper (II) acetylacetonate, copper (II) naphthenate, copper (II) acetate, copper (II) (meth)acrylate, copper (II) salicylate, and copper thiourea or ethylenediaminetetraacetic acid complex; vanadium (IV) compounds such as vanadyl acetylacetonate; iron (II) compounds such as phenanthroline iron (II); iron (III) compounds such as iron (III) (meth)acrylate and iron (III) acetoacetonate; cobalt (II) and cobalt (III) compounds such as cobalt (II) octoate, cobalt (II) succinate, cobalt (II) naphthenate, cobalt (II) resinate, cobalt (II) linoleate, cobalt acetoacetate ester, dicarboxylic acid semi-ester, and compounds having chelate-bonded copper (for example, cobalt (II) bis(acetylacetonate), cobalt (III) tris(acetylacetonate)), cobalt chelates of 2-acetylcyclopentanone and methyl cyclopentanone-2-carboxylate; manganese (II) compounds such as manganese (II) bis(acetylacetonate); manganese (III) compounds such as manganese (III) tris(acetylacetonate); and cobalt (III) compounds such as cobalt (III) tris(acetylacetonate).

[0050] Other usable polyvalent metal compounds include, for example, chlorides, hydroxides, carbonates, bicarbonates, sulfates, nitrates, and acetates of copper (II), vanadium (IV), iron (II) and iron (III), cobalt (II) and cobalt (III), and manganese (II) and manganese (III).

[0051] The polyvalent metal compound preferably contains at least one selected from the group consisting of copper (II) compounds and vanadium (IV) compounds.

[0052] The liquid adhesive can contain the polyvalent metal compound in an effective amount. The liquid adhesive can contain the polyvalent metal compound in an amount of about 0.05 parts by mass or more, about 0.25 parts by mass or more, or about 0.40 parts by mass or more, and about 2 parts by mass or less, about 1 part by mass or less, or about 0.6 parts by mass or less, based on 100 parts by mass in total of the free radical polymerizable compounds. For example, the liquid adhesive preferably contains the polyvalent metal compound in an amount of about 0.05 parts by mass to about 2 parts by mass, more preferably about 0.25 parts by mass to about 1 part by mass, and still more preferably about 0.4 parts by mass to about 0.6 parts by mass, based on 100 parts by mass in total of the free radical polymerizable compounds.

[0053] The liquid adhesive preferably further contains a quaternary ammonium halide. The quaternary ammonium halide is preferably at least partially soluble in the liquid adhesive. By using the quaternary ammonium halide, a relatively thickly applied liquid adhesive can be cured to the inside. Without being bound by any theory, it is considered that the halide ions of the quaternary ammonium halide promote the generation of active species and accelerate the radical reaction, and the generated relatively inactive halide radicals diffuse to allow the radical reaction to proceed even inside the liquid adhesive.

[0054] Suitable quaternary ammonium halides include those having four hydrocarbyl groups (e.g., alkyl, alkenyl, cycloalkyl, aralkyl, alkaryl, aryl, or combinations thereof). Each hydrocarbyl group is independently selected preferably from hydrocarbyl groups having 1 to 18 carbon atoms, more preferably 1 to 12 carbon atoms, and even more preferably 1 to 4 carbon atoms. Suitable hydrocarbyl groups include, for example, methyl, ethyl, propyl, butyl, hexyl, octyl, dodecyl, hexadecyl, octadecyl, benzyl, phenyl, tolyl, cyclohexyl, and methylcyclohexyl. Suitable quaternary ammonium compounds include, for example, tetramethylammonium halide, tetraethylammonium halide, tetrapropylammonium halide, tetrabutylammonium halide, ethyltrimethylammonium halide, diethyldimethylammonium halide, butyltrimethylammonium halide, methyltrioctylammonium halide, and benzyltributylammonium halide. Any halide (e.g., F, Cl, Br, I) ion may be used for the quaternary ammonium halide. The halide ion is preferably Cl - or Br - and more preferably Cl - is.

[0055] When using a quaternary ammonium halide, its amount is not particularly limited, but the liquid adhesive can contain the quaternary ammonium halide in an amount of about 0.03 parts by mass or more, about 0.1 parts by mass or more, or about 0.2 parts by mass or more, and about 1 part by mass or less, about 0.6 parts by mass or less, or about 0.4 parts by mass or less, based on 100 parts by mass in total of the free radical polymerizable compounds. For example, the liquid adhesive can contain the quaternary ammonium halide in an amount of preferably about 0.03 parts by mass to about 1 part by mass, more preferably about 0.1 parts by mass to about 0.6 parts by mass, and even more preferably about 0.2 parts by mass to about 0.4 parts by mass, based on 100 parts by mass in total of the free radical polymerizable compounds.

[0056] The liquid adhesive may contain a solvent. Examples of the solvent include ketones such as acetone, methyl ethyl ketone, and cyclohexanone; esters such as ethyl acetate and butyl acetate; and alcohols such as ethanol and butanol.

[0057] In one embodiment, the liquid adhesive is solvent-free. The solvent-free liquid adhesive can be suitably used for applications where the liquid adhesive is cured in a sealed space.

[0058] The liquid adhesive may further contain, as optional additives, a thickener, a plasticizer, a dispersant, a filler, a flame retardant, or an anti-thermal aging agent.

[0059] The liquid adhesive can be produced by mixing the above components. Components that do not flow at room temperature may be heated and then mixed with other components.

[0060] In one embodiment, the viscosity of the liquid adhesive is about 100 mPa·s or more and about 10,000 mPa·s or less at 25°C. When the liquid adhesive is applied by spin coating, by setting the viscosity of the liquid adhesive to about 1,000 mPa·s or more, or about 2,000 mPa·s or more and about 8,000 mPa·s or less, or about 5,000 mPa·s or less at 25°C, the liquid adhesive can be uniformly applied onto the wafer with a desired thickness. The viscosity is a value read at 30 seconds after the start of measurement after waiting for 60 seconds after setting the liquid adhesive between the cone and the plate under the conditions of a temperature of 25°C, a cone diameter of 35 mm, a cone angle of 1 degree, and a rotation speed of 1 degree / minute using a cone and plate viscometer (HAAKE (trademark) rheometer, Thermo Fisher Scientific K.K., Minato-ku, Tokyo, Japan).

[0061] The photo-thermal conversion layer ink compositions of the first embodiment and the second embodiment both contain a photoabsorbent having thermal decomposability and a binder or a precursor thereof. The photo-thermal conversion layer ink composition of the second embodiment further contains a β-dicarbonyl compound or a salt thereof, which will be described in detail later.

[0062] A light absorber having thermal decomposability (hereinafter also simply referred to as "light absorber") is a substance that absorbs radiant energy such as laser irradiation and converts it into heat, and itself thermally decomposes. For example, in the case of carbon black particles which are one of the light absorbers having thermal decomposability, when it becomes high temperature due to light absorption, combustion (in the presence of oxygen) or graphitization occurs, and it decomposes while generating gas and loses the shape of the particles. As a result, voids are generated in the photothermal conversion layer, and the photothermal conversion layer is decomposed and separated into two layers. Thereby, the support and the base material on both sides of the photothermal conversion layer can be easily separated without applying unnecessary stress.

[0063] As the light absorber, one that absorbs the radiant energy of the wavelength to be used can be selected. As the radiant energy, laser light having a wavelength of usually 150 to 2000 nm, preferably 300 to 1100 nm can be used. Specifically, a YAG laser that generates light having a wavelength of 1064 nm, a second harmonic YAG laser having a wavelength of 532 nm, a semiconductor laser having a wavelength of 780 to 1300 nm, a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength 193 nm), an F2 excimer laser (wavelength 157 nm), a XeCl laser (wavelength 308 nm), a XeF laser (wavelength 351 nm), and a solid UV laser (wavelength 355 nm) can be mentioned. As the radiant energy, ultraviolet rays generated from a high-pressure mercury lamp (wavelength 254 nm or more and 436 nm or less), for example, g-line (wavelength 436 nm), h-line (wavelength 405 nm), or i-line (wavelength 365 nm) can also be used.

[0064] Examples of the light absorber include black pigments such as carbon black, graphite powder, and black titanium oxide; inorganic materials that specifically absorb laser wavelengths such as cesium-doped tungsten oxide (CWO); black dyes, red dyes, or purple dyes such as aromatic diamine-based metal complexes, aliphatic diamine-based metal complexes, aromatic dithiol-based metal complexes, mercaptophenol-based metal complexes, squarylium-based compounds, cyanine-based dyes, methine-based dyes, naphthoquinone-based dyes, and anthraquinone-based dyes; and UV-absorbing compounds such as octyl methoxycinnamate, octyl dimethoxybenzylidene dioxoimidazolidine propionate, hexyl diethylamino hydroxybenzoyl benzoate, t-butyl methoxydibenzoylmethane, octyl triazone, 2-ethylhexyl paramethoxycinnamate, and dihydroxybenzophenone.

[0065] The light absorber is preferably in particulate form in the photo-thermal conversion layer ink composition. In other words, the particulate light absorber preferably has low compatibility with the binder and its precursor, or the solvent of the photo-thermal conversion layer ink composition, and is dispersed without being dissolved in the photo-thermal conversion layer ink composition. When the particulate light absorber absorbs light and converts it into heat and reaches a high temperature, changes such as oxidation, decomposition, and phase change gradually progress from the particle surface toward the particle interior. Therefore, the particle interior can maintain its light absorption ability for a while. Therefore, when the particulate light absorber is viewed in terms of particles, photo-thermal conversion can occur continuously for a longer time at the position where the particulate light absorber exists inside the photo-thermal conversion layer, and voids can be effectively generated inside the photo-thermal conversion layer. From this perspective, the particulate light absorber is preferably a black pigment.

[0066] The average primary particle size of the particulate light absorber is preferably about 10 nm or more, or about 20 nm or more, about 400 nm or less, or about 300 nm or less. In the present disclosure, the average primary particle size of a particulate substance is the value obtained by measuring the particle diameters (equivalent circular diameters) of 1000 or more primary particles randomly in an image taken at a magnification of 50,000 to 200,000 using a transmission electron microscope after aggregating the aggregates into primary particles using an ultrasonic disperser in a solvent in which the substance is insoluble.

[0067] In one embodiment, the light absorber contains carbon black particles. Examples of the carbon black particles include thermal black particles, acetylene black particles, gas furnace black particles, oil furnace black particles, and channel black particles. The carbon black particles can significantly reduce the force required for separating the substrate and the light-transmissive support after irradiation with radiant energy.

[0068] The content of the carbon black particles in the light absorber can be about 40% by mass or more, about 50% by mass or more, or about 60% by mass or more based on the mass of the light absorber. In one embodiment, the light absorber is carbon black particles.

[0069] The average primary particle size of the carbon black particles is preferably about 10 nm or more, or about 20 nm or more, about 400 nm or less, or about 300 nm or less.

[0070] The carbon black particles preferably include hydrophilic carbon black particles. The hydrophilic carbon black particles have hydrophilic functional groups, such as carboxyl groups, on their surfaces. Therefore, the hydrophilic carbon black particles can exhibit self-dispersibility in the photothermal conversion layer ink composition and can be highly dispersed. By using the hydrophilic carbon black particles, it is also possible to avoid the use of a dispersant that may gel the binder or its precursor in the photothermal conversion layer ink composition and improve the storage stability of the photothermal conversion layer ink composition.

[0071] A dye that selectively absorbs the wavelength of radiant energy and transmits other wavelength regions may be used in combination with the carbon black particles. This is useful when forming a photothermal conversion layer that selectively transmits alignment light in the dicing process.

[0072] The content of the light absorber in the photo-thermal conversion layer ink composition varies depending on the type, particle morphology, and dispersibility of the light absorber. However, based on the volume of the solid content, it can be about 5% by volume or more, about 10% by volume or more, or about 15% by volume or more, and about 60% by volume or less, about 45% by volume or less, or about 35% by volume or less. By setting the content of the light absorber to about 5% by volume or more, voids can be more effectively generated inside the photo-thermal conversion layer, and the substrate and the light-transmissive support can be separated with low stress. By setting the content of the light absorber to about 60% by volume or less, the film-forming property of the photo-thermal conversion layer and the adhesiveness to the adjacent layer can be ensured.

[0073] The content of the light absorber in the photo-thermal conversion layer ink composition varies depending on the type, particle morphology, and dispersibility of the light absorber. However, based on the mass of the solid content, it can be about 10% by mass or more, about 15% by mass or more, or about 18% by mass or more, and about 65% by mass or less, about 55% by mass or less, or about 45% by mass or less. By setting the content of the light absorber to about 10% by mass or more, voids can be more effectively generated inside the photo-thermal conversion layer, and the substrate and the light-transmissive support can be separated with low stress. By setting the content of the light absorber to about 65% by mass or less, the film-forming property of the photo-thermal conversion layer and the adhesiveness to the adjacent layer can be ensured.

[0074] As the binder or its precursor, a thermally decomposable resin can be used. Examples of the thermally decomposable resin include cellulose esters such as gelatin, cellulose, cellulose acetate, and nitrocellulose; polyphenols; polyvinyl butyral; polyvinyl acetal; polycarbonate; polyurethane; polyester; polyorthoester; polyacetal; polyvinyl alcohol; polyvinyl pyrrolidone; copolymers of vinylidene chloride and acrylonitrile; poly(meth)acrylate; polyvinyl chloride; silicone resin; and block copolymers containing polyurethane units. The thermally decomposable resin can be used alone or as a mixture of two or more. In order to form a void layer by thermal decomposition of the thermally decomposable resin and prevent the separated photothermal conversion layer from re-adhering, the glass transition temperature (Tg) of the thermally decomposable resin is preferably 20°C or higher, more preferably 100°C or higher. When the light-transmissive support is glass, a thermally decomposable resin having a polar group (e.g., -COOH, -OH, etc.) capable of forming a hydrogen bond with the silanol group on the glass surface in the molecule can be used to enhance the adhesion between the glass and the photothermal conversion layer. In applications using chemical solutions such as wet etching, a thermally decomposable resin having a functional group capable of self-crosslinking by heat treatment, or a thermally decomposable resin or its precursor capable of crosslinking with ultraviolet light or visible light can be used to impart chemical resistance to the photothermal conversion layer.

[0075] The total content of the binder and its precursor in the photothermal conversion layer ink composition can be about 30% by volume or more, about 40% by volume or more, or about 45% by volume or more, and about 95% by volume or less, about 80% by volume or less, or about 65% by volume or less, based on the volume of the solid content. By setting the total content to about 30% by volume or more, the film-forming property of the photothermal conversion layer and the adhesion to the adjacent layer can be ensured, and the chemical resistance of the photothermal conversion layer can be enhanced. By setting the total content to about 95% by volume or less, voids can be more effectively generated inside the photothermal conversion layer, and the substrate and the light-transmissive support can be separated with low stress.

[0076] The total content of the binder and its precursor in the photothermal conversion layer ink composition can be about 25% by mass or more, about 35% by mass or more, or about 40% by mass or more, and about 80% by mass or less, about 70% by mass or less, or about 60% by mass or less, based on the mass of the solid content. By setting the total content to about 25% by mass or more, the film-forming property of the photothermal conversion layer and the adhesiveness to the adjacent layer can be ensured, and the chemical resistance of the photothermal conversion layer can be enhanced. By setting the total content to about 80% by mass or less, voids can be more effectively generated inside the photothermal conversion layer, and the substrate and the light-transmissive support can be separated with low stress.

[0077] The photothermal conversion layer ink composition of one embodiment further includes a transparent filler. The transparent filler acts so that the photothermal conversion layer separated by the generation of voids due to thermal decomposition of the light absorber does not re-adhere. Examples of the transparent filler include silica, talc, and barium sulfate. The transparent filler can enhance the peelability between the substrate and the light-transmissive support after irradiation with radiant energy.

[0078] The average primary particle size of the transparent filler can be about 7 nm or more, about 10 nm or more, or about 15 nm or more, and about 40 nm or less, about 30 nm or less, or about 25 nm or less.

[0079] The total content of the light absorber and the optional transparent filler in the photothermal conversion layer ink composition is preferably about 5% by volume or more, about 20% by volume or more, or about 35% by volume or more, and about 70% by volume or less, about 60% by volume or less, or about 55% by volume or less, based on the volume of the solid content. By setting the total content to about 5% by volume or more, voids can be more effectively generated inside the photothermal conversion layer, and the substrate and the light-transmissive support can be separated with low stress. By setting the total content to about 70% by volume or less, the film-forming property of the photothermal conversion layer and the adhesiveness to the adjacent layer can be ensured, and the chemical resistance of the photothermal conversion layer can be enhanced.

[0080] The total content of the light absorber and the optional transparent filler in the photothermal conversion layer ink composition is preferably about 10% by mass or more, about 25% by mass or more, or about 40% by mass or more, and about 75% by mass or less, about 65% by mass or less, or about 60% by mass or less, based on the mass of the solid content. By setting the total content to about 10% by mass or more, voids can be more effectively generated inside the photothermal conversion layer, and the substrate and the light-transmissive support can be separated with low stress. By setting the total content to about 75% by mass or less, the film-forming property of the photothermal conversion layer and the adhesion to the adjacent layer can be ensured, and the chemical resistance of the photothermal conversion layer can be enhanced.

[0081] The photothermal conversion layer ink composition may contain other additives as required. Examples of other additives include leveling agents, silane coupling agents, foaming agents, sublimating agents, thickeners, and viscosity modifiers.

[0082] The photothermal conversion layer ink composition may contain a solvent for dissolving or dispersing other components. Examples of the solvent include alcohols such as water, methanol, ethanol, and isopropanol; ketones such as acetone and methyl ethyl ketone; and esters such as ethyl acetate and butyl acetate. The solvent is preferably water, alcohol, or a mixed solvent of water and alcohol.

[0083] The solid content of the photothermal conversion layer ink composition can be appropriately determined in consideration of the coating property, drying property or curability of the photothermal conversion layer ink composition, and the thickness of the photothermal conversion layer to be formed. The solid content of the photothermal conversion layer ink composition in one embodiment is about 3% by mass or more, about 5% by mass or more, or about 10% by mass or more, and about 30% by mass or less, about 25% by mass or less, or about 20% by mass or less.

[0084] The viscosity of the photothermal conversion layer ink composition can be appropriately determined in consideration of the coatability, drying property or curability of the photothermal conversion layer ink composition, and the thickness of the photothermal conversion layer to be formed. The viscosity of the photothermal conversion layer ink composition of one embodiment is about 3 mPa·s or more, about 5 mPa·s or more, or about 10 mPa·s or more, and about 200 mPa·s or less, about 100 mPa·s or less, or about 50 mPa·s or less. The photothermal conversion layer ink composition having a viscosity of about 10 mPa·s or more and about 50 mPa·s or less can be suitably used for spin coating. The viscosity is measured using a rheometer (RotoVisco 1 manufactured by HAAKE) at a temperature of 25°C and a shear rate of 100 sec -1 and is the value measured under these conditions.

[0085] The curing accelerator of the first embodiment and the photothermal conversion layer ink composition of the second embodiment contain a β-dicarbonyl compound or a salt thereof. The β-dicarbonyl compound is represented by the following formula. [Chemical formula]

[0086] R 1 and R 2 each independently represent a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms. R 1 and R 2 each preferably have 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, and still more preferably 1 to 4 carbon atoms. R 1 and R 2Examples include methyl, ethyl, isopropyl, n-propyl, butyl, pentyl, hexyl, octyl, decyl, dodecyl, hexadecyl, and octadecyl. Generally, the nature of the substituent in a substituted hydrocarbyl group (which may be mono- or polysubstituted) is not particularly important, except when it is desirable to avoid, to the extent possible, the use of substituents that interfere with free radical polymerization. Examples of substituted hydrocarbyl groups include hydroxyhydrocarbyl groups (e.g., hydroxyethyl and hydroxypropyl), alkoxyhydrocarbyl groups (e.g., methoxyethyl and methoxyethoxy), alkanoylhydrocarbyl groups (e.g., acetylethyl and benzoylethyl), haloalkyl groups (e.g., chloroethyl and dichloropropyl), and dialkylaminohydrocarbyl groups (e.g., dimethylaminopropyl and diethylaminoethyl).

[0087] In some embodiments, R 1 、R 2 、and R 3 Any two of which may combine together to form a 5- or 6-membered ring. In these embodiments, for example, R 1 、R 2 and R 3 Two of which combine together to form

Chemical formula

Chemical formula

Chemical formula

[0088] R 3 represents hydrogen or a hydrocarbyl group or substituted hydrocarbyl group having 1 to 18 carbon atoms. Examples of R 3 include, for example, methyl, ethyl, isopropyl, n-propyl, butyl, pentyl, hexyl, octyl, decyl, dodecyl, hexadecyl, phenyl, cyclohexyl, methylcyclohexyl, and octadecyl. Examples of the substituted hydrocarbyl include, for example, -CH2C(=O)OR 4 . In the formula, R 4 is as defined above, that is, it represents H or a hydrocarbyl group having 1 to 18 carbon atoms. For example, R 4 may be H, methyl, ethyl, dodecyl or octadecyl.

[0089] X1 and X 2 are, independently, a covalent bond, O, S,

Chem.

Chem.

[0090] In some embodiments, the β-dicarbonyl compound is barbituric acid (i.e., R 3 = H, and both X 1 and X 2 are

Chem.

[0091] Useful salts of the β-dicarbonyl compound include, for example, alkali metal (e.g., lithium, sodium, potassium, or cesium) salts, NH4 +Salts, and primary, secondary, tertiary or quaternary organic ammonium salts are included. The organic ammonium salt preferably has 1 to 24 carbon atoms. Examples of the organic ammonium salt include tetrabutylammonium salt, dibenzyldimethylammonium salt, benzyltributylammonium salt, and tetraethylammonium salt.

[0092] The content of the β-dicarbonyl compound or its salt in the curing accelerator of the first embodiment is not particularly limited, but can be about 1% by mass or more, about 2% by mass or more, or about 5% by mass or more, and about 20% by mass or less, about 17% by mass or less, or about 15% by mass or less. For example, the curing accelerator preferably contains the β-dicarbonyl compound or its salt in an amount of about 1% by mass to about 20% by mass, more preferably about 2% by mass to about 17% by mass, and still more preferably about 5% by mass to about 15% by mass.

[0093] The content of the β-dicarbonyl compound or its salt in the photothermal conversion layer ink composition of the second embodiment is not particularly limited, but based on the mass of the solid content, it can be about 5% by mass or more, about 10% by mass or more, or about 15% by mass or more, and about 50% by mass or less, about 40% by mass or less, or about 30% by mass or less. For example, the photothermal conversion layer ink composition preferably contains the β-dicarbonyl compound or its salt in an amount of about 5% by mass to about 50% by mass, more preferably about 10% by mass to about 40% by mass, and still more preferably about 15% by mass to about 30% by mass.

[0094] The curing accelerator of the first embodiment may contain a solvent. As the solvent, those that can dissolve the β-dicarbonyl compound are preferred, and examples include ketones such as acetone, methyl ethyl ketone, and cyclohexanone; esters such as ethyl acetate and butyl acetate; and alcohols such as ethanol and butanol.

[0095] The kit of one embodiment essentially does not contain an organic peroxide and a photopolymerization initiator. For example, the total content of the organic peroxide and the photopolymerization initiator in the kit can be less than 1% by mass, less than 0.1% by mass, or less than 0.01% by mass.

[0096] The laminate (Laminate A) of the third embodiment includes a light-transmissive support, a photothermal conversion layer disposed on the light-transmissive support, and a curing acceleration layer disposed on the photothermal conversion layer. The photothermal conversion layer includes the above-described light absorber having thermal decomposability and a binder. The curing acceleration layer includes the above-described β-dicarbonyl compound or a salt thereof.

[0097] FIG. 1 shows a schematic cross-sectional view of the laminate (Laminate A) of the third embodiment. The laminate 10 includes a light-transmissive support 12, a photothermal conversion layer 14, and a curing acceleration layer 16.

[0098] The laminate (Laminate B) of the fourth embodiment includes a light-transmissive support and a photothermal conversion layer disposed on the light-transmissive support. The photothermal conversion layer includes the above-described light absorber having thermal decomposability, a binder, and a β-dicarbonyl compound or a salt thereof.

[0099] FIG. 2 shows a schematic cross-sectional view of the laminate (Laminate B) of the fourth embodiment. The laminate 10 includes a light-transmissive support 12 and a photothermal conversion layer 14.

[0100] The light-transmissive support is formed of a material that can transmit radiant energy such as laser light. The light-transmissive support is desirably a material that maintains the substrate (for example, a semiconductor wafer) in a flat state and does not break during processes such as back grinding and conveyance. The transmittance of the light-transmissive support is desirably, for example, about 50% or more for the target radiant energy.

[0101] Examples of the light-transmissive support include glass and acrylic resin. In order to enhance the adhesive force with an adjacent layer such as the photothermal conversion layer, the light-transmissive support may be surface-treated with a silane coupling agent or the like as necessary. Examples of the shape of the light-transmissive support include a circle and a rectangle. The light-transmissive support may be plate-shaped.

[0102] In one embodiment, the light-transmissive support is glass. Examples of the glass include fused silica glass, sapphire glass, and borosilicate glass.

[0103] The light-transmissive support desirably has sufficient rigidity to prevent warping of the substrate (e.g., semiconductor wafer). The light-transmissive support preferably has a Young's modulus of 1 to 10 MPa and a thickness of 500 μm or more.

[0104] The light-transmissive support may be exposed to high temperatures due to heat generated in the photo-thermal conversion layer during irradiation with radiant energy, frictional heat during back grinding, etc. Alternatively, before peeling the semiconductor chip from the light-transmissive support, processes such as etching such as CMP, resin molding, wet etching, dry etching, PVD such as evaporation and sputtering, CVD, plating such as electrolytic plating and electroless plating, pattern formation by photolithography, and high-temperature treatment for forming an oxide film on the surface of the silicon wafer may be added. Depending on these processes, a light-transmissive support having heat resistance, chemical resistance, or a low expansion rate can be selected. Examples of the light-transmissive support having heat resistance, chemical resistance, and a low expansion rate include glasses such as fused silica glass, borosilicate glass, and sapphire glass, specifically, Pyrex (registered trademark), Corning #1737 and #7059 (Corning Inc.), and Tempax (Schott AG).

[0105] After the back grinding process and before dicing, wet etching of the semiconductor wafer surface with a chemical solution may be performed as an intermediate process. This process is performed to remove the damage layer on the back surface of the semiconductor wafer generated by grinding and increase the flexural strength of the wafer. Alternatively, as the final stage of the semiconductor wafer thinning process, wet etching may be used to remove a thickness of several tens of micrometers. When the semiconductor wafer is a silicon (Si) single crystal, a mixed acid containing hydrogen fluoride is generally used as the etching chemical solution. At this time, when the light transmissive support is glass (excluding sapphire glass), the end portion of the light transmissive support is also etched by the chemical solution. Therefore, when the light transmissive support is reused, the glass can be protected from corrosion by hydrogen fluoride by previously providing an acid-resistant (etching chemical solution-resistant) protective film on the glass. As the protective film, an acid-resistant resin can be used. It is desirable that the acid-resistant resin can be dissolved in an organic solvent, applied in solution form, and fixed on the glass by drying. Further, it is desirable that the acid-resistant resin transmits a sufficient amount of light having a laser wavelength irradiated for separating the glass from the semiconductor wafer. From such a viewpoint, suitable acid-resistant resins include, for example, amorphous polyolefins, cyclic olefin copolymers, and polyvinyl chloride that do not contain a condensed bond in the molecule.

[0106] It is desirable that the thickness of the light transmissive support is uniform. For example, in order to thin a silicon wafer to 50 μm or less and make its uniformity ±10% or less, it is desirable that the variation in the thickness of the light transmissive support is ±2 μm or less. When the light transmissive support is repeatedly used, it is desirable that the light transmissive support has scratch resistance. When the light transmissive support is repeatedly used, it is desirable to select the material of the light transmissive support in consideration of the wavelength of the radiation energy so as to suppress damage to the light transmissive support by the radiation energy. For example, when using Pyrex (registered trademark) glass as the light transmissive support and irradiating it with a third harmonic YAG laser (355 nm), it is possible to separate the light transmissive support from the semiconductor wafer or semiconductor chip, but there are cases where the light transmissive support absorbs the radiation energy and suffers thermal damage, making it impossible to reuse it.

[0107] The radiant energy irradiated in the form of laser light or the like onto the photothermal conversion layer of the laminate is absorbed by the light absorber and converted into thermal energy. The generated thermal energy rapidly raises the temperature of the photothermal conversion layer, and at that temperature, the light absorber itself thermally decomposes. Depending on the types of the light absorber and the binder, gas may be generated during the thermal decomposition of the light absorber. As a result, voids are formed in the photothermal conversion layer, and the photothermal conversion layer is decomposed and separated into two layers. Thereby, the support and the base material on both sides of the photothermal conversion layer can be easily separated without applying unnecessary stress.

[0108] The photothermal conversion layer of laminate A can be formed on a light-transmissive support using the photothermal conversion layer ink composition of the first embodiment.

[0109] The photothermal conversion layer of laminate B can be formed on a light-transmissive support using the photothermal conversion layer ink composition of the second embodiment. Thereby, laminate B can be obtained.

[0110] The photothermal conversion layer ink composition is applied onto the light-transmissive support by spin coating, bar coating, roll coating, cast coating, spraying, etc., and heated, for example, to about 100°C to about 250°C, and the binder precursor is converted into a binder as necessary, whereby the photothermal conversion layer can be formed.

[0111] The thickness of the photothermal conversion layer can be about 0.1 μm or more, about 0.3 μm or more, or about 0.5 μm or more, and about 5 μm or less, about 3 μm or less, or about 2 μm or less. By setting the thickness of the photothermal conversion layer to about 0.1 μm or more, the film formability and adhesiveness of the photothermal conversion layer can be maintained. By setting the thickness of the photothermal conversion layer to about 5 μm or less, the residue on the support can be reduced after decomposing the photothermal conversion layer.

[0112] The curing accelerator layer of laminate A is formed by applying the curing accelerator of the first embodiment onto the photothermal conversion layer of laminate A by spin coating, bar coating, roll coating, cast coating, spraying, etc., and heating it to, for example, about 40°C to about 150°C, and volatilizing the solvent as necessary. Thereby, laminate A can be obtained.

[0113] The curing accelerator layer of laminate A is preferably formed thinly, and it is often difficult to determine the thickness. The areal concentration of the β-dicarbonyl compound or its salt in the curing accelerator layer of laminate A is about 2 ng / cm 2 or more, about 5 ng / cm 2 or more, or about 8 ng / cm 2 or more, about 30 ng / cm 2 or less, about 20 ng / cm 2 or less, or about 15 ng / cm 2 or less. For example, the areal concentration of the β-dicarbonyl compound or its salt in the curing accelerator layer of laminate A is preferably about 2 ng / cm 2 to about 30 ng / cm 2 , more preferably about 5 ng / cm 2 to about 20 ng / cm 2 , still more preferably about 8 ng / cm 2 to about 15 ng / cm 2 . The areal concentration is determined by washing and removing the curing accelerator layer with a solvent such as acetone and quantifying the washing solution using GC-MS.

[0114] The content of the β-dicarbonyl compound or its salt in the photothermal conversion layer of laminate B can be about 5% by mass or more, about 10% by mass or more, or about 15% by mass or more, about 50% by mass or less, about 40% by mass or less, or about 30% by mass or less. For example, the photothermal conversion layer of laminate B preferably contains the β-dicarbonyl compound or its salt in an amount of about 5% by mass to about 50% by mass, more preferably about 10% by mass to about 40% by mass, and still more preferably about 15% by mass to about 30% by mass.

[0115] The laminate (laminate C) of the fifth embodiment includes a light-transmissive support, a photothermal conversion layer, a bonding layer disposed on the photothermal conversion layer, and a substrate disposed on the bonding layer, and the photothermal conversion layer and the substrate are bonded by the bonding layer. The photothermal conversion layer can be decomposed by irradiation with radiant energy such as laser light and separated into two, and separated from the light-transmissive support without damaging the substrate.

[0116] FIG. 3 shows a schematic cross-sectional view of the laminate (laminate C) of the fifth embodiment. The laminate 20 includes a light-transmissive support 12, a photothermal conversion layer 14, a bonding layer 22 disposed on the photothermal conversion layer 14, and a substrate 24 disposed on the bonding layer 22, and the photothermal conversion layer 14 and the substrate 24 are bonded via the bonding layer 22.

[0117] The laminate C can be manufactured by the following method using the kit of the first embodiment. The method includes applying a free-radical polymerizable liquid adhesive to the substrate to form a precursor bonding layer on the substrate; applying a photothermal conversion layer ink composition to the light-transmissive support to form a photothermal conversion layer on the light-transmissive support; applying a curing accelerator on the photothermal conversion layer to form a curing acceleration layer on the photothermal conversion layer; and laminating the substrate and the light-transmissive support so that the precursor bonding layer and the curing acceleration layer are in contact with each other, and at least partially curing the precursor bonding layer, thereby forming a bonding layer.

[0118] The precursor bonding layer can be formed by applying a liquid adhesive onto the substrate by spin coating, bar coating, roll coating, cast coating, spraying, etc., and volatilizing the solvent as necessary.

[0119] The formation of the photothermal conversion layer and the formation of the curing acceleration layer are as described for laminate A. Therefore, instead of performing these formation steps, a previously prepared laminate A can also be used.

[0120] The formation of the bonding layer is performed by laminating the substrate and the light-transmissive support so that the bonding precursor layer and the curing accelerator layer are in contact with each other, and at least partially curing the bonding precursor layer. The polyvalent metal compound contained in the bonding precursor layer and the β-dicarbonyl compound or its salt contained in the curing accelerator layer are mixed in the vicinity of the interface between these layers to initiate a radical reaction, and the polymerization of the free radical polymerizable compound contained in the bonding precursor layer proceeds by the generated active species. As a result, a bonding layer in which the bonding precursor layer is at least partially cured is formed, and a laminate C in which the substrate and the light-transmissive support are bonded via the bonding layer is obtained. The formation of the laminate C is preferably performed under vacuum in order to prevent the incorporation of air between the layers.

[0121] When forming the bonding layer, the laminate may be left at room temperature or heated. When heating the laminate, for example, it can be heated at a temperature of about 40 °C or higher, or about 60 °C or higher, about 250 °C or lower, or about 150 °C or lower.

[0122] The formation time of the bonding layer can be, for example, about 1 hour to about 24 hours at room temperature. When heating the laminate, for example, it can be about 3 minutes to about 3 hours.

[0123] The laminate C can also be produced by the following method using the kit of the second embodiment. The method includes applying a free radical polymerizable liquid adhesive to a substrate to form a bonding precursor layer on the substrate; applying a photothermal conversion layer ink composition to a light-transmissive support to form a photothermal conversion layer on the light-transmissive support; and laminating the substrate and the light-transmissive support so that the bonding precursor layer and the photothermal conversion layer are in contact with each other, and at least partially curing the bonding precursor layer, thereby forming a bonding layer.

[0124] The formation of the bonding precursor layer is as described above. The formation of the photothermal conversion layer is as described for the laminate B. Therefore, instead of performing the step of forming the photothermal conversion layer, a previously prepared laminate B can also be used.

[0125] The formation of the bonding layer is carried out by laminating the substrate and the light-transmissive support so that the bonding precursor layer and the photothermal conversion layer are in contact with each other, and at least partially curing the bonding precursor layer. The polyvalent metal compound contained in the bonding precursor layer and the β-dicarbonyl compound or its salt contained in the photothermal conversion layer are mixed in the vicinity of the interface between these layers to initiate a radical reaction, and the polymerization of the free radical polymerizable compound contained in the bonding precursor layer proceeds by the generated active species. As a result, a bonding layer in which the bonding precursor layer is at least partially cured is formed, and a laminate C in which the substrate and the light-transmissive support are bonded via the bonding layer is obtained. The formation of the laminate C is preferably carried out under vacuum in order to prevent the incorporation of air between the layers.

[0126] When forming the bonding layer, the laminate may be left at room temperature or heated. In order to promote the diffusion of the β-dicarbonyl compound or its salt contained in the photothermal conversion layer and increase the reaction opportunity with the polyvalent metal compound contained in the bonding precursor layer, it is preferable to heat the laminate. The heating temperature of the laminate can be, for example, about 40 °C or higher, or about 60 °C or higher, about 250 °C or lower, or about 150 °C or lower.

[0127] The formation time of the bonding layer can be, for example, about 1 hour to about 24 hours at room temperature. When the laminate is heated, it can be, for example, about 3 minutes to about 3 hours.

[0128] When the substrate is separated from the light-transmissive support, generally, the substrate is obtained with the bonding layer attached. Therefore, it is desirable that the bonding layer can be easily peeled off from the substrate. The bonding layer preferably has sufficient adhesive strength (holding force) to fix the substrate to the light-transmissive support, but has a low adhesive strength that can be peeled off after heat treatment.

[0129] The thickness of the bonding layer preferably ensures absorption of surface irregularities of the substrate, uniformity regarding the thickness required for processes such as back grinding, and tear strength required when peeling off the bonding layer. When removing the bonding layer using a chemical solution, tear strength is not particularly required for the bonding layer. In one embodiment, the thickness of the bonding layer is about 3 μm or more, or about 10 μm or more, about 150 μm or less, or about 100 μm or less.

[0130] Examples of the substrate include those containing III-V compound semiconductors such as silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbide (SiC), gallium arsenide (GaAs), or II-VI compound semiconductors such as zinc sulfide (ZnS). The substrate may be in the shape of a semiconductor wafer, and a structure such as a circuit pattern may be formed on the surface in contact with the bonding layer. In one embodiment, the substrate is intended to be thinned by back grinding in a laminated state. Other examples of the substrate include a quartz wafer, sapphire, glass, and quartz.

[0131] When the substrate is a semiconductor wafer having a circuit pattern, the circuit may be damaged by radiant energy such as laser light that passes through the light-transmissive support, the photothermal conversion layer, and the bonding layer and reaches the semiconductor wafer. To avoid such damage, a dye that absorbs light of the wavelength of the radiant energy or a pigment that reflects it may be included in any of the layers forming the laminate, or a layer containing such a dye or pigment may be further provided between the photothermal conversion layer and the semiconductor wafer. Examples of the dye that absorbs laser light include phthalocyanine-based dyes and cyanine-based dyes having an absorption peak near the wavelength of the laser light used. Examples of the pigment that reflects laser light include inorganic white pigments such as titanium oxide.

[0132] A method for manufacturing a thinned substrate according to an embodiment includes preparing a laminate C in which the substrate is a substrate to be ground, grinding the substrate to be ground until it reaches a desired thickness, irradiating radiant energy through a light-transmissive support onto a photothermal conversion layer to decompose the photothermal conversion layer, thereby separating the ground substrate having an adhesive layer from the light-transmissive support, and, if necessary, removing the adhesive layer from the ground substrate.

[0133] FIG. 4 shows an explanatory diagram of a method for manufacturing a thinned substrate according to an embodiment. In FIG. 4(a), a laminate 20 (laminate C) is shown. As shown in (b), the substrate 24, which is the substrate to be ground, is ground to form a thinned substrate 25. As shown in (c), radiant energy such as laser light (indicated by the upward arrow) is irradiated onto the photothermal conversion layer 14 through the light-transmissive support 12 to decompose the photothermal conversion layer 14. In (c), the photothermal conversion layer 14 separates into two at the position of the dotted line. As shown in (d), the thinned substrate 25 after grinding having an adhesive layer 22 is separated from the light-transmissive support (not shown). As shown in (e), the adhesive layer 22 is removed from the thinned substrate 25 after grinding to obtain the thinned substrate 25.

[0134] The grinding of the substrate to be ground can be performed using a grinding apparatus including a pedestal capable of sucking and fixing the object to be ground, a spindle, and a grinding wheel rotatably attached to the lower end of the spindle. The light-transmissive support side of the laminate C is placed on the pedestal of the grinding apparatus, and the laminate C is sucked and fixed to the pedestal. Then, while supplying a water stream to the laminate C, the rotating grinding wheel is brought into contact to grind the substrate to be ground. The grinding can be performed until the thickness of the substrate to be ground becomes about 150 μm or less, preferably about 50 μm or less, more preferably about 25 μm or less.

[0135] Irradiation with radiant energy can be performed using laser light. Examples of the laser light include a YAG laser (wavelength 1064 nm), a second harmonic YAG laser (wavelength 532 nm), a semiconductor laser (wavelength 780 - 1300 nm), a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength 193 nm), an F2 excimer laser (wavelength 157 nm), a XeCl laser (wavelength 308 nm), a XeF laser (wavelength 351 nm), and a solid UV laser (wavelength 355 nm). Irradiation with radiant energy can also be performed using ultraviolet rays generated from a high-pressure mercury lamp (wavelength 254 nm or more and 436 nm or less), for example, g-line (wavelength 436 nm), h-line (wavelength 405 nm), or i-line (wavelength 365 nm).

[0136] Irradiation with radiant energy can be performed in a state where the ground laminate is suction-fixed to a fixing table with the light-transmissive support on the upper surface. When using laser light, the depth of focus of the laser light is preferably as deep as about 30 μm or more in order to stably separate the base material from the light-transmissive support. The laser output can be 0.3 - 100 W, the scan speed can be 0.1 - 40 m / second, and the beam diameter can be 5 μm - 300 μm. The processing speed may be increased by increasing the laser output and increasing the scan speed. When there is a margin in the laser output, the processing speed may be increased by increasing the beam diameter and reducing the number of scans. The scan of the laser light is desirably performed from the end of the ground laminate and without gaps. For example, the laser light may be linearly reciprocally scanned in a tangential direction of the base material from the end, or may be scanned spirally from the end toward the center.

[0137] After decomposing the photothermal conversion layer by irradiation with radiant energy, the light-transmissive support is separated from the ground base material using a vacuum pickup or the like.

[0138] After separating the light-transmissive support from the ground substrate, if necessary, the bonding layer is removed from the ground substrate. To remove the bonding layer, an adhesive tape for removing the bonding layer that can form an adhesive force higher than the adhesive force between the ground substrate and the bonding layer can be used. The adhesive tape for removing the bonding layer is adhered onto the bonding layer, and the bonding layer can be peeled off from the ground substrate. Alternatively or additionally, the bonding layer may be removed by washing with a solvent. Examples of the solvent include acetone, methyl ethyl ketone, N-methylpyrrolidone, N-ethylpyrrolidone, N-methylsuccinimide, dimethylfuran, toluene, N,N'-dimethylacetamide, tris(dimethylamino)phosphine oxide, dimethyl sulfoxide, and γ-butyrolactone.

[0139] After the grinding process, if necessary, processes such as chemical mechanical polishing (CMP), resin molding, wet etching, dry etching, etc., physical vapor deposition (PVD) such as evaporation and sputtering, chemical vapor deposition (CVD), electroplating, electroless plating, etc., pattern formation by photolithography, and formation of an oxide film on the surface of a silicon wafer may be performed. After the grinding process, before irradiation with radiation energy, or after the bonding layer removal process, dicing may be performed to separate the thinned substrate into a plurality of small pieces. When the thinned substrate is a semiconductor wafer, the small pieces are semiconductor chips. The dicing process can be performed using a dicing tape and a dicing frame, and, if necessary, a die bonding tape.

[0140] The laminate (Laminate D) of the sixth embodiment further includes a light-transmissive support, a photothermal conversion layer, a bonding layer disposed on the photothermal conversion layer, and a semiconductor substrate disposed on the bonding layer. The semiconductor substrate has an insulating layer disposed on the surface of the semiconductor substrate on the side opposite to the bonding layer, and one or a plurality of conductive connection portions that penetrate the insulating layer and are electrically connected to the semiconductor substrate.

[0141] Fig. 5 shows a schematic cross-sectional view of the laminate (laminate D) of this embodiment. The laminate 30 further includes a light-transmissive support 12, a photothermal conversion layer 14, a bonding layer 32 disposed on the photothermal conversion layer 14, and a semiconductor substrate 34 disposed on the bonding layer 32. The semiconductor substrate 34 has an insulating layer 342 disposed on the surface of the semiconductor substrate 34 on the side opposite to the bonding layer 32, and one or a plurality of conductive connection portions 344 penetrating through the insulating layer 342 and electrically connected to the semiconductor substrate 34.

[0142] Examples of the semiconductor substrate include a silicon wafer and an SOI substrate on which a plurality of semiconductor chips are formed. The semiconductor chips include, for example, integrated circuits such as ICs and LSIs, or imaging devices such as CCDs.

[0143] The insulating layer and the conductive connection portion can be formed using known semiconductor process technologies, such as photolithography, physical vapor deposition (PVD) such as evaporation and sputtering, plating such as electrolytic plating and electroless plating, and etching such as wet etching and dry etching. In one embodiment, the insulating layer contains silicon oxide (SiO2) or a polyimide resin. In one embodiment, the conductive connection portion contains copper.

[0144] The laminate D can be manufactured in the same procedure as the laminate C, except that the base material is the semiconductor substrate.

[0145] A method for manufacturing a semiconductor substrate laminate according to an embodiment includes preparing a laminate D in which a base material is a semiconductor substrate; preparing a second semiconductor substrate having a second insulating layer disposed on a surface of the second semiconductor substrate and one or more second conductive connection portions that penetrate the second insulating layer and are electrically connected to the second semiconductor substrate; heating and pressing the semiconductor substrate against the second semiconductor substrate with the conductive connection portion of the semiconductor substrate facing the second conductive connection portion of the second semiconductor substrate, thereby forming a semiconductor substrate laminate in which the conductive connection portion and the second conductive connection portion are joined and the insulating layer and the second insulating layer are joined; irradiating radiant energy to a photothermal conversion layer through a light-transmissive support to decompose the photothermal conversion layer, thereby separating the semiconductor substrate laminate having a bonding layer from the light-transmissive support; and, if necessary, removing the bonding layer from the surface of the semiconductor substrate laminate. This manufacturing method is a type of hybrid bonding.

[0146] FIG. 6 shows an explanatory diagram of the method for manufacturing a semiconductor substrate laminate according to this embodiment. FIG. 6(a) shows a laminate 30 (laminate D) and a second semiconductor substrate 44. The second semiconductor substrate 44 has a second insulating layer 442 disposed on its surface and one or more second conductive connection portions 444 that penetrate the second insulating layer 442 and are electrically connected to the second semiconductor substrate 44. The conductive connection portion 344 of the semiconductor substrate 34 included in the laminate 30 faces the second conductive connection portion 444 of the second semiconductor substrate 44. In (b), the semiconductor substrate 34 and the second semiconductor substrate 44 are heated and pressed together. Thereby, the conductive connection portion 344 and the second conductive connection portion 444 are joined, and the insulating layer 342 and the second insulating layer 442 are joined. As shown in (c), radiant energy such as laser light (indicated by the upward arrow) is irradiated to the photothermal conversion layer 14 through the light-transmissive support 12 to decompose the photothermal conversion layer 14. In (c), the photothermal conversion layer 14 separates into two at the position of the dotted line. As shown in (d), the semiconductor substrate laminate having the bonding layer 14 and the light-transmissive support (not shown) are separated. As shown in (e), the bonding layer 32 is removed from the surface of the semiconductor substrate laminate to obtain a semiconductor substrate laminate 50.

[0147] As the second semiconductor substrate, the same substrate as the semiconductor substrate in the laminate D can be used.

[0148] Thermal compression bonding between the semiconductor substrate and the second semiconductor substrate can be performed under conditions of a temperature of 300°C to 450°C and a pressure of 200 to 400 MPa for 20 minutes to 60 minutes.

[0149] In one embodiment, the insulating layer and the conductive connection portion of the semiconductor substrate, and the second insulating layer and the second conductive connection portion of the second semiconductor substrate are formed by a CMP method (damascene method) using copper for the conductive connection portion and the second conductive connection portion, and using a silicon oxide (SiO2) film for the insulating layer and the second insulating layer. In the CMP process, since the etching rate of copper is higher than the etching rate of silicon oxide, the copper surface after the CMP process is slightly recessed (dishing) compared to the surface of the surrounding silicon oxide insulating layer. Also, the fact that the copper surface is lower than the surface of the surrounding silicon oxide insulating layer acts advantageously on the reliable bonding between the insulating layer and the second insulating layer in the thermal compression bonding process. The thermal expansion coefficient of copper is larger than that of silicon oxide. Therefore, during the thermal compression bonding process, copper expands and the conductive connection portion and the second conductive connection portion come into contact, and mutual diffusion of copper occurs at the contact portion, filling the gap formed by the depression on the copper surface, and penetrating through the oxide film and impurities on the copper surface to electrically connect the conductive connection portion and the second conductive connection portion. Also, due to the progress of the condensation reaction of silicon oxide in the high-temperature environment of the thermal compression bonding process, bonding between the insulating layer and the second insulating layer also occurs simultaneously.

[0150] Irradiation of radiant energy and separation of the semiconductor substrate laminate and the light-transmissive support can be performed in the same manner as the method for manufacturing the thinned substrate described above.

[0151] Removal of the bonding layer from the surface of the semiconductor substrate laminate can be performed in the same manner as the method for manufacturing the thinned substrate described above.

[0152] The kits and laminates of the present disclosure can be used in various applications including temporary fixing applications. Specifically, the kits and laminates can be suitably used for the production of highly densely mounted laminated CSP (Chip Size Package), through-type CSP that requires high functionality and high speed, ultra-thin compound semiconductors (such as GaAs) that require improved heat dissipation efficiency, electrical characteristics, and stability, and semiconductor chips using large wafers such as 16-inch silicon wafers.

Example

[0153] In the following examples, specific embodiments of the present disclosure are illustrated, but the present invention is not limited thereto. All parts and percentages are by mass unless otherwise specified. Numerical values include errors essentially resulting from the measurement principle and measurement apparatus. Numerical values are shown as significant figures with normal rounding.

[0154] The materials, reagents, etc. used in the examples and comparative examples are shown in Table 1.

Table 1

[0155] Examples 1 to 4 and Comparative Examples 1 to 8 1. Preparation of liquid adhesive For the examples and comparative examples other than Comparative Example 8, UV-3300B and Light Acrylate 1.6HX-A were placed in a light-resistant plastic bottle and mixed with a planetary centrifugal mixer for 5 minutes. Then, the remaining components listed in Table 2 were added and mixed with the planetary centrifugal mixer for another 5 minutes to prepare a liquid adhesive.

[0156] For Comparative Example 8, Light Acrylate 1.6HX-A and Omnirad (trademark) 819 were stirred until Omnirad (trademark) 819 was completely dissolved. Then, UV-3300B was placed in a light-resistant plastic bottle and mixed with a planetary centrifugal mixer for 5 minutes to prepare a UV-curable liquid adhesive.

[0157] 2. Preparation of curing accelerator The components listed in Table 2 were mixed to prepare a curing accelerator.

[0158] The formulations of the liquid adhesive and the curing accelerator are shown in Table 2.

[0159]

Table 2

[0160] 3. Formation of the light-to-heat conversion (LTHC) layer Using a bead mill, the components shown in Table 3 were mixed to prepare a light-to-heat conversion layer ink composition. As the light-transmissive support, a disk-shaped glass substrate with a diameter of 154 mm and a thickness of 800 μm was used. The light-to-heat conversion layer ink composition was applied onto the glass substrate using a spin coater, heated at 100 °C for 5 minutes, and then further heated at 200 °C for 1 hour to form the LTHC layer.

[0161]

Table 3

[0162] 4. Formation of the curing acceleration layer In the examples and comparative examples other than Comparative Examples 1 to 3 and Comparative Example 8, using a spin coater, the curing accelerator was applied onto the LTHC layer at a rotation speed of 700 rpm for 10 seconds, and then dried in a drying oven set at 40 °C for 3 minutes to form the curing acceleration layer. After forming the curing acceleration layer, the curing acceleration layer was stored under the conditions described in the "Storage state of the curing acceleration layer" column of Table 4, and then used for the formation of the laminate.

[0163] The amount of the initiator applied onto the glass substrate was quantified by washing and removing the curing acceleration layer with acetone and measuring the washing solution using GC-MS.

[0164] 5. Formation of the laminate As a semiconductor device wafer model, a silicon wafer with a diameter of 152 mm and a thickness of 750 μm was used. A liquid adhesive was applied onto the silicon wafer using a spin coater. A glass substrate having an LTHC layer and the silicon wafer coated with the adhesive were bonded using a coating and laminating apparatus WSS8101M (manufactured by Tatsumo Co., Ltd., Okayama City, Okayama Prefecture, Japan). After bonding, the laminate was heat-treated under the conditions described in Table 4 to cure the liquid adhesive. Only in Comparative Example 8, the liquid adhesive was cured by irradiating ultraviolet light from the glass substrate side of the laminate. The laminate had a structure of glass substrate / LTHC layer / bonding layer / silicon wafer, the thickness of the LTHC layer was 0.9 μm, and the thickness of the bonding layer was 50 μm.

[0165] 6. Laser separation A dicing tape and a dicing frame were placed on the silicon wafer of the laminate, and the laminate was transferred onto the stage of a support peeling apparatus TWS (manufactured by Tatsumo Co., Ltd., Okayama City, Okayama Prefecture, Japan). The pressure was reduced from the lower side by a vacuum device to adsorb and fix the laminate on the stage. Laser irradiation was performed from the glass substrate side of the laminate using a YAG laser (wavelength 1064 nm) under the conditions of a laser output of 6.0 W, a beam diameter of 100 μm, a scanning pitch of 100 μm, and a laser scanning speed of 1.0 m / s. The laser beam was linearly reciprocated in the tangential direction from the edge portion of the laminate to irradiate the entire surface of the laminate. A suction device was attached to the glass substrate of the laser-irradiated laminate, and it was checked by hand whether the glass substrate and the silicon wafer were easily separated.

[0166] 7. Evaluation of the curing performance of the adhesive Twenty hours after forming the laminate, the glass substrate was removed from the laminate, and the bonding layer was peeled from the silicon wafer. Next, the peeled bonding layer was cut into an appropriate size to obtain a sample, and the mass of the sample was weighed using an analytical balance. During the measurement, the sample was exposed to ionized air to ensure that the measurement was not affected by static electricity. Then, the sample was immersed in methyl ethyl ketone and held for 12 hours. The sample taken out from methyl ethyl ketone was dried in a drying oven set at 60 °C for 3 hours, and then the mass of the sample was weighed in the same manner as before immersion. The mass retention rate was calculated from the following formula. Mass retention rate (%, gel fraction) = mass after immersion (g) / mass before immersion (g)

[0167] Table 4 shows the mass retention rates of the examples and comparative examples, the observation results of the cured bonding layer, and the evaluation results of laser separation. Table 4 also shows the storage state of the curing acceleration layer, the storage state of the liquid adhesive before coating, and the heat treatment conditions of the laminate.

[0168]

Table 4

[0169] Example 1 showed a high mass retention rate regardless of the presence or absence of heat treatment during the curing of the liquid adhesive. No change in the reactivity of the liquid adhesive was observed even after storage at room temperature for 3 months. Since there was no change in the mass retention rate even after leaving the curing acceleration layer at 100°C for 7 days, it was shown that 1-benzyl-5-phenylbarbituric acid contained in the curing acceleration layer is very stable. Storage at 100°C for 7 days is equivalent to storage at room temperature for more than 2 years. Examples 2 to 4 also showed the same high mass retention rate as Example 1.

[0170] In Comparative Example 1, 1-benzyl-5-phenylbarbituric acid was blended into the adhesive. The liquid adhesive of Comparative Example 1 reacted and gelled in 1 month even when stored at low temperature. The liquid adhesive of Comparative Example 2 required refrigerated storage below 5°C. The liquid adhesive of Comparative Example 3 required high-temperature curing at 200°C.

[0171] In Comparative Examples 4 and 5, a method of applying a peroxide that can cleave and react even at room temperature in the presence of a metal catalyst onto the LTHC layer was attempted. However, the mass retention rate decreased when stored at room temperature for several days (3 days to 5 days). Furthermore, at the end of the laminate, that is, where the liquid adhesive was in contact with the atmosphere, the liquid adhesive did not cure.

[0172] In Comparative Example 6 and Comparative Example 7, a method of applying a peroxide that promotes a cleavage reaction by heating to a temperature exceeding 100°C onto the LTHC layer was attempted. However, the reaction was insufficient at 100°C, and the adhesive was uncured at the ends of the laminate.

[0173] The mass retention rate of Comparative Example 8 using ultraviolet curing was at the same level as that of Examples 1 to 4.

[0174] Examples 5 and 6 1. Formation of the photothermal conversion (LTHC) layer Using a bead mill, the components shown in Table 5 were mixed to prepare a photothermal conversion layer ink composition. As the light-transmissive support, a disk-shaped glass substrate with a diameter of 154 mm and a thickness of 800 μm was used. The photothermal conversion layer ink composition was applied onto the glass substrate using a spin coater, heated at 100°C for 5 minutes, and then further heated at 180°C for 1 hour to form the LTHC layer. The LTHC layer contained 1-benzyl-5-phenylbarbituric acid as the β-dicarbonyl compound.

[0175] [Table 5]

[0176] 2. Formation of the laminate, laser separation, and evaluation of the curing performance of the adhesive A laminate was formed in the same procedure as in Example 1, except that a glass substrate having an LTHC layer containing 1-benzyl-5-phenylbarbituric acid was used. Laser separation of the laminate and evaluation of the curing performance of the adhesive were performed in the same procedure as in Example 1.

[0177] The mass retention rates and the observation results of the cured bonding layers of Examples 5 and 6 are shown in Table 6. Table 6 also shows the content of the β-dicarbonyl compound in the LTHC layer, the storage state of the liquid adhesive before coating, and the heat treatment conditions of the laminate.

[0178] [Table 6]

[0179] In Example 5, the adhesive hardened up to the end by heat treatment at 100°C. When the LTHC layer was left at room temperature for two months, the mass retention rate improved. In Example 6, regardless of the presence or absence of heat treatment, the adhesive hardened up to the end and showed a relatively high mass retention rate.

[0180] It is obvious to those skilled in the art that various improvements and changes of the present invention can be made without departing from the scope and spirit of the present invention. Some embodiments of the present disclosure are described below. [Aspect 1] A free-radical polymerizable liquid adhesive containing at least one free-radical polymerizable compound and at least one polyvalent metal compound for polymerizing the at least one free-radical polymerizable compound, and A photothermal conversion layer ink composition containing a light absorber having thermodegradability and a binder or its precursor, and A β-dicarbonyl compound represented by the following formula or a salt thereof [Chemical formula] (In the formula, X 1 and X 2 each independently represents a covalent bond, O, S, [Chemical formula] or [Chemical formula] represents, R 4 each independently represents H or a hydrocarbyl group having 1 to 18 carbon atoms, R 1 and R 2 each independently represents a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, R 3 represents hydrogen, or a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, or R 1 , R 2 , or R 3Any two of them combine to form a 5-membered or 6-membered ring.) A curing accelerator, and A kit for forming a laminate including a photothermal conversion layer, comprising [Aspect 2] A free radical polymerizable liquid adhesive including at least one free radical polymerizable compound and at least one polyvalent metal compound for polymerizing the at least one free radical polymerizable compound, and A light absorber having thermal decomposability, a binder or a precursor thereof, and a β-dicarbonyl compound represented by the following formula or a salt thereof [Chemical formula] (In the formula, X 1 and X 2 are independently a covalent bond, O, S, [Chemical formula] or [Chemical formula] represents, R 4 each independently represents H or a hydrocarbyl group having 1 to 18 carbon atoms, R 1 and R 2 independently represent a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, R 3 represents hydrogen, or a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, or R 1 , R 2 , or R 3 Any two of them combine to form a 5-membered or 6-membered ring.) A photothermal conversion layer ink composition, and A kit for forming a laminate including a photothermal conversion layer, comprising [Aspect 3] The kit according to aspect 1 or 2, wherein the at least one polyvalent metal compound contains at least one selected from the group consisting of copper (II), vanadium (IV), iron (II), iron (III), cobalt (II), cobalt (III), manganese (II), and manganese (III). [Aspect 4] The kit according to any one of aspects 1 to 3, wherein the free radical polymerizable liquid adhesive further contains a quaternary ammonium halide. [Aspect 5] The kit according to any one of aspects 1 to 4, wherein the β-dicarbonyl compound is barbituric acid or a derivative thereof. [Aspect 6] The kit according to any one of aspects 1 to 5, wherein the at least one free radical polymerizable compound contains a free radical polymerizable (meth)acrylate oligomer. [Aspect 7] The kit according to any one of aspects 1 to 6, wherein the at least one free radical polymerizable compound contains a free radical polymerizable polyfunctional (meth)acrylate. [Aspect 8] The kit according to any one of aspects 1 to 7, which essentially does not contain an organic peroxide and a photoinitiator. [Aspect 9] A light-transmissive support, A photothermal conversion layer disposed on the light-transmissive support, A curing acceleration layer disposed on the photothermal conversion layer, A laminate comprising: The photothermal conversion layer contains a light absorber having pyrolytic properties and a binder, The curing acceleration layer is a β-dicarbonyl compound represented by the following formula or a salt thereof [Chemical formula] (In the formula, X 1 and X 2 are independently a covalent bond, O, S, [Chemical formula] or [Chemical formula] represents, and R 4 each independently represents H or a hydrocarbyl group having 1 to 18 carbon atoms, R 1 and R 2 each independently represents a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, R 3 represents hydrogen, or a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, or R 1 , R 2 , or R 3 any two of which combine to form a 5-membered or 6-membered ring.) A laminate comprising [Aspect 10] A light-transmissive support, and a photothermal conversion layer disposed on the light-transmissive support, and a laminate comprising, wherein the photothermal conversion layer comprises a light absorber having thermal decomposability, a binder, and a β-dicarbonyl compound represented by the following formula or a salt thereof [Chemical formula] (In the formula, X 1 and X 2 each independently represents a covalent bond, O, S, [Chemical formula] or [Chemical formula] represents, and R 4 each independently represents H or a hydrocarbyl group having 1 to 18 carbon atoms, R 1 and R 2 each independently represents a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, R 3 represents hydrogen, a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, or R 1 , R 2 , or R 3 any two of which combine together to form a 5 - or 6 - membered ring.) A laminate comprising . [Aspect 11] The laminate according to Aspect 9 or 10, wherein the light - transmissive support is glass. [Aspect 12] Applying a free - radical polymerizable liquid adhesive to a substrate to form a pre - bonding precursor layer on the substrate, Applying a photo - thermal conversion layer ink composition to a light - transmissive support to form a photo - thermal conversion layer on the light - transmissive support, Applying a curing accelerator on the photo - thermal conversion layer to form a curing accelerator layer on the photo - thermal conversion layer, and Bonding the substrate and the light - transmissive support so that the pre - bonding precursor layer and the curing accelerator layer are in contact, and at least partially curing the pre - bonding precursor layer to thereby form a bonding layer. A method for manufacturing a laminate including a photo - thermal conversion layer, comprising wherein the free - radical polymerizable liquid adhesive contains at least one free - radical polymerizable compound and at least one polyvalent metal compound for polymerizing the at least one free - radical polymerizable compound, the photo - thermal conversion layer ink composition contains a photo - absorber having thermal decomposability and a binder or a precursor thereof, the curing accelerator is a β - dicarbonyl compound represented by the following formula or a salt thereof [Chemical formula] (In the formula, X 1 and X 2 are independently a covalent bond, O, S, [Chemical formula] or [Chemical formula] represents, and R 4 each independently represents H or a hydrocarbyl group having 1 to 18 carbon atoms, R 1 and R 2 each independently represents a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, R 3 represents hydrogen, or a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, or R 1 R 2 or R 3 any two of which combine together to form a 5-membered or 6-membered ring.) A method comprising . [Aspect 13] Applying a free-radical polymerizable liquid adhesive to a substrate to form a pre-bonding precursor layer on the substrate, Applying a photo-thermal conversion layer ink composition to a light-transmissive support to form a photo-thermal conversion layer on the light-transmissive support, and Bonding the substrate and the light-transmissive support so that the pre-bonding precursor layer and the photo-thermal conversion layer are in contact, and at least partially curing the pre-bonding precursor layer to thereby form a bonding layer, A method for manufacturing a laminate including a photo-thermal conversion layer, comprising wherein the free-radical polymerizable liquid adhesive includes at least one free-radical polymerizable compound and at least one polyvalent metal compound for polymerizing the at least one free-radical polymerizable compound, wherein the photo-thermal conversion layer ink composition includes a photoabsorbent having thermal decomposability, a binder or a precursor thereof, and a β-dicarbonyl compound or a salt thereof represented by the following formula [Chemical formula] (In the formula, X 1 and X 2 each independently represents a covalent bond, O, S, [Chemical formula] or [Chemical formula] represents, R 4 each independently represents H or a hydrocarbyl group having 1 to 18 carbon atoms, R 1 and R 2 each independently represents a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, R 3 represents hydrogen, or a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, or R 1 , R 2 , or R 3 any two of which combine together to form a 5-membered or 6-membered ring.) A method comprising [Aspect 14] The method according to Aspect 12 or 13, wherein the light-transmissive support is glass. [Aspect 15] Preparing a laminate obtained by the method according to any one of Aspects 12 to 14, wherein the substrate is a substrate to be ground, Grinding the substrate to be ground until it reaches a desired thickness, Irradiating radiant energy through the light-transmissive support onto the photothermal conversion layer to decompose the photothermal conversion layer, thereby separating the ground substrate having the bonding layer from the light-transmissive support, and Optionally, removing the bonding layer from the ground substrate A method for manufacturing a thinned substrate, comprising [Aspect 16] Preparing a laminate obtained by the method according to any one of Aspects 12 to 14, wherein the base material is a semiconductor substrate, and the semiconductor substrate has an insulating layer disposed on the surface of the semiconductor substrate on the side opposite to the bonding layer, and one or more conductive connection portions that penetrate the insulating layer and are electrically connected to the semiconductor substrate. Preparing a second semiconductor substrate having a second insulating layer disposed on the surface of the second semiconductor substrate, and one or more second conductive connection portions that penetrate the second insulating layer and are electrically connected to the second semiconductor substrate. Opposing the conductive connection portion of the semiconductor substrate and the second conductive connection portion of the second semiconductor substrate, and thermocompression bonding the semiconductor substrate and the second semiconductor substrate, whereby the conductive connection portion and the second conductive connection portion are joined, and the insulating layer and the second insulating layer are joined to form a semiconductor substrate laminate. Irradiating radiant energy to the photothermal conversion layer through the light-transmissive support to decompose the photothermal conversion layer, thereby separating the semiconductor substrate laminate having the bonding layer from the light-transmissive support, and Optionally, removing the bonding layer from the surface of the semiconductor substrate laminate. A method for manufacturing a semiconductor substrate laminate, including the above steps.

Description of Reference Numerals

[0181] 10, 20, 30 Laminate 12 Light-transmissive support 14 Photothermal conversion layer 16 Curing acceleration layer 22 Bonding layer 24 Base material 25 Thinned base material 32 Bonding layer 34 Semiconductor substrate 342 Insulating layer 344 Conductive connection portion 44 Second semiconductor substrate 442 Second insulating layer 444 Second conductive connection portion 50 Semiconductor substrate laminate

Claims

1. A free-radical polymerizable liquid adhesive comprising at least one free-radical polymerizable compound and at least one polyvalent metal compound for polymerizing the at least one free-radical polymerizable compound, and A photothermal conversion layer ink composition comprising a photothermal decomposable light absorber and a binder or a precursor thereof, and A β-dicarbonyl compound represented by the following formula or a salt thereof 【Chemical 1】 (wherein, X １ and X ２ are independently a covalent bond, O, S, [Chemical 2] or 【Chemical 3】 represents, and R ４ each independently represents H or a hydrocarbyl group having 1 to 18 carbon atoms, R １ and R ２ each independently represents a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, R ３ represents hydrogen, a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, or R １ 、 R ２ 、 or R ３ Any two of them combine to form a 5-membered or 6-membered ring. A curing accelerator comprising, and A kit for forming a laminate comprising a photothermal conversion layer.

2. A free-radical polymerizable liquid adhesive comprising at least one free-radical polymerizable compound and at least one polyvalent metal compound for polymerizing the at least one free-radical polymerizable compound, and A photothermal conversion layer ink composition comprising a photothermal decomposable light absorber, a binder or a precursor thereof, and a β-dicarbonyl compound represented by the following formula or a salt thereof 【Chemical Formula 4】 (wherein, X １ and X ２ are independently a covalent bond, O, S, 【Chemical Formula 5】 or [Chemical Formula 6] represents, and R ４ each independently represents H or a hydrocarbyl group having 1 to 18 carbon atoms, R １ and R ２ each independently represents a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, R ３ represents hydrogen, a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, or R １ , R ２ , or R ３ where any two of them combine to form a 5- or 6-membered ring.) A kit for forming a laminate comprising a photothermal conversion layer.

3. The kit according to claim 1 or 2, wherein the at least one polyvalent metal compound comprises at least one selected from the group consisting of copper (II), vanadium (IV), iron (II), iron (III), cobalt (II), cobalt (III), manganese (II), and manganese (III).

4. The kit according to claim 1 or 2, wherein the free-radical polymerizable liquid adhesive further comprises a quaternary ammonium halide.

5. The kit according to claim 1 or 2, wherein the β-dicarbonyl compound is barbituric acid or a derivative thereof.

6. The kit according to claim 1 or 2, wherein the at least one free-radical polymerizable compound comprises a free-radical polymerizable (meth)acrylate oligomer.

7. The kit according to claim 1 or 2, wherein the at least one free-radical polymerizable compound comprises a free-radical polymerizable polyfunctional (meth)acrylate.

8. The kit according to claim 1 or 2, wherein the kit essentially does not contain an organic peroxide and a photoinitiator.

9. A light-transmissive support, A photothermal conversion layer disposed on the light-transmissive support, A curing acceleration layer disposed on the photothermal conversion layer, A laminate comprising, The photothermal conversion layer comprises a photothermal decomposable light absorber and a binder, The curing acceleration layer is a β-dicarbonyl compound represented by the following formula or a salt thereof 【Chemical Formula 7】 (wherein X １ and X ２ are each independently a covalent bond, O, S, 【Chemical Formula 8】 or 【Chemical Formula 9】 represents R ４ each independently represents H or a hydrocarbyl group having 1 to 18 carbon atoms, R １ and R ２ each independently represents a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, R ３ represents hydrogen, a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, or R １ , R ２ , or R ３ Any two of them combine to form a 5-membered or 6-membered ring.) A laminate comprising

10. A light-transmissive support, A photothermal conversion layer disposed on the light-transmissive support, A laminate comprising The photothermal conversion layer contains a light absorber having thermal decomposability, a binder, and a β-dicarbonyl compound represented by the following formula or a salt thereof 【Chemical 10】 (wherein, X １ and X ２ are independently a covalent bond, O, S, 【Chemical Formula 11】 Or 【Chemical 12】 represents, and R ４ each independently represents H or a hydrocarbyl group having 1 to 18 carbon atoms, R １ and R ２ each independently represents a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, R ３ represents hydrogen, a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, or R １ , R ２ , or R ３ Any two of them combine to form a 5-membered or 6-membered ring.) A laminate comprising

11. The laminate according to claim 9 or 10, wherein the light-transmissive support is glass.

12. Applying a free-radical polymerizable liquid adhesive to a substrate to form a bonding precursor layer on the substrate, Applying a photothermal conversion layer ink composition to a light-transmissive support to form a photothermal conversion layer on the light-transmissive support, Applying a curing accelerator on the photothermal conversion layer to form a curing accelerator layer on the photothermal conversion layer, and Bonding the substrate and the light-transmissive support so that the bonding precursor layer and the curing accelerator layer are in contact, and at least partially curing the bonding precursor layer, thereby forming a bonding layer. A method for manufacturing a laminate including a photothermal conversion layer, comprising The free-radical polymerizable liquid adhesive contains at least one free-radical polymerizable compound and at least one polyvalent metal compound for polymerizing the at least one free-radical polymerizable compound, The photothermal conversion layer ink composition contains a light absorber having thermal decomposability and a binder or a precursor thereof, The curing accelerator contains a β-dicarbonyl compound represented by the following formula or a salt thereof 【Chemical 13】 (wherein X １ and X ２ are independently a covalent bond, O, S, 【Chemical 14】 Or 【Chemical Formula 15】 represents, and R ４ each independently represents H or a hydrocarbyl group having 1 to 18 carbon atoms, R １ and R ２ each independently represents a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, R ３ represents hydrogen, a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, or R １ , R ２ , or R ３ Any two of them combine to form a 5-membered or 6-membered ring.) A method comprising

13. Applying a free-radical polymerizable liquid adhesive to a substrate to form a bonding precursor layer on the substrate, Applying a photothermal conversion layer ink composition to a light-transmissive support to form a photothermal conversion layer on the light-transmissive support, and Bonding the substrate and the light-transmissive support so that the bonding precursor layer and the photothermal conversion layer are in contact, and at least partially curing the bonding precursor layer, thereby forming a bonding layer. A method for manufacturing a laminate including a photothermal conversion layer, comprising The free-radical polymerizable liquid adhesive contains at least one free-radical polymerizable compound and at least one polyvalent metal compound for polymerizing the at least one free-radical polymerizable compound, The photothermal conversion layer ink composition contains a light absorber having thermal decomposability, a binder or a precursor thereof, and a β-dicarbonyl compound represented by the following formula or a salt thereof 【Chemical 16】 (wherein, X １ and X ２ are each independently a covalent bond, O, S, 【Chemical 17】 Or 【Chemical 18】 represents R ４ each independently represents H or a hydrocarbyl group having 1 to 18 carbon atoms, R １ and R ２ each independently represents a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, R ３ represents hydrogen, a hydrocarbyl group or a substituted hydrocarbyl group having 1 to 18 carbon atoms, or R １ , R ２ , or R ３ where any two of them combine to form a 5-membered or 6-membered ring.) A method comprising

14. The method according to claim 12 or 13, wherein the light-transmissive support is glass.

15. Preparing a laminate obtained by the method according to claim 12 or 13, wherein the substrate is a substrate to be ground, Grinding the substrate to be ground until the substrate to be ground reaches a desired thickness, Irradiating radiant energy to the photothermal conversion layer through the light-transmissive support to decompose the photothermal conversion layer, thereby separating the ground substrate having the bonding layer from the light-transmissive support, and Removing the bonding layer from the ground substrate, if necessary A method for manufacturing a thinned substrate, comprising.

16. Preparing a laminate obtained by the method according to claim 12 or 13, wherein the substrate is a semiconductor substrate, and the semiconductor substrate has an insulating layer disposed on a surface of the semiconductor substrate on a side opposite to the bonding layer, and one or more conductive connection portions penetrating the insulating layer and electrically connected to the semiconductor substrate, Preparing a second semiconductor substrate having a second insulating layer disposed on a surface of the second semiconductor substrate, and one or more second conductive connection portions penetrating the second insulating layer and electrically connected to the second semiconductor substrate, Opposing the conductive connection portion of the semiconductor substrate and the second conductive connection portion of the second semiconductor substrate, and thermocompression bonding the semiconductor substrate and the second semiconductor substrate to form a semiconductor substrate laminate in which the conductive connection portion and the second conductive connection portion are joined and the insulating layer and the second insulating layer are joined, Irradiating radiant energy to the photothermal conversion layer through the light-transmissive support to decompose the photothermal conversion layer, thereby separating the semiconductor substrate laminate having the bonding layer from the light-transmissive support, and Removing the bonding layer from the surface of the semiconductor substrate laminate, if necessary A method for manufacturing a semiconductor substrate laminate, comprising.

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