Transfer stamp material, temperature-sensitive adhesive material composition, micro-transfer printing device, and transfer printing method

Abstract

A transfer stamp material according to the present invention contains a polymer (A) having, in a side chain, at least one specific group selected from the group consisting of an alkyl group having at least 10 carbon atoms and a group in which some methylene groups in an alkyl group having at least 10 or more carbon atoms have been substituted with -O-, -S-, -CO-, -COO-, -OCO-, -NR1A-, -CO-NR1A-, -NR1A-CO-, -NR1A-CO-NR1B-, -NR1A-CO-O-, or -O-CO-NR1A-. R1A and R1B are each independently a hydrogen atom or an alkyl group having one to three carbon atoms.

Description

Transfer stamp material, temperature-sensitive adhesive composition, microtransfer printing device, and transfer printing method

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to Japanese Patent Application No. 2024-147840, filed on August 29, 2024, the entire contents of which are incorporated herein by reference. The present disclosure relates to a transfer stamp material, a temperature-sensitive adhesive composition, a micro-transfer printing device, and a transfer printing method.

[0002] Transfer printing is expected to be a hybrid optical integration technology that enables flexible and sophisticated integration of heterogeneous materials. In recent years, development of micro-transfer printing has been promoted, in which various microelements, which are used in optical integrated circuits and have sizes on the order of micrometers to nanometers and are made of heterogeneous materials, are transferred from a source substrate to a target substrate by transfer printing (see, for example, Patent Documents 1 to 3).

[0003] Patent Documents 1 to 3 disclose the use of a viscoelastic elastomer such as polydimethylsiloxane as the material for the transfer stamp. In these Patent Documents 1 to 3, a microelement is adhered to a transfer stamp material formed from the viscoelastic elastomer, the transfer stamp is lifted up from a source substrate to pick up the microelement, the lifted microelement is brought into contact with a target substrate, and then the transfer stamp is separated from the target substrate to release the microelement, thereby transferring the element.

[0004] US Patent Application Publication No. 2024 / 0038570 International Publication No. 2023 / 217637 Special Publication No. 2017-524250

[0005] In the process of transferring microelements from a source substrate to a target substrate by microtransfer printing, existing transfer stamps made of materials such as polydimethylsiloxane have the problem that if a microelement adhered to the transfer stamp material is brought into contact with the target substrate and then the transfer stamp is separated from the target substrate at a fast separation speed, the microelement remains adhered to the transfer stamp material and is pulled up along with the transfer stamp, resulting in poor element transfer. On the other hand, considering the improvement of manufacturing throughput and reduction of manufacturing costs in the mass production of optical integrated circuits, the transfer process using a transfer stamp requires that the transfer stamp exhibit high adhesion to the microelements, quickly pick up the microelements from the source substrate, and quickly release the microelements onto the target substrate.

[0006] Furthermore, from the viewpoint of improving yield, it is necessary to enable the element release operation to be performed quickly, while minimizing contamination caused by residues of the transfer stamp (i.e., adhesive residue) on the surface of the released microelement and target substrate after transferring the microelement onto the target substrate.

[0007] The present disclosure has been made in consideration of the above-mentioned problems, and one of its objectives is to provide a transfer stamp material that can form a transfer stamp that can increase the element pickup and release speeds and suppress the occurrence of contamination by residue after element transfer.

[0008] Another object of the present invention is to provide a transfer stamp, a microtransfer printing device, and a transfer printing method that can increase the element pickup and release speeds and suppress the occurrence of contamination due to residue after element transfer. Still another object of the present invention is to provide a temperature-sensitive adhesive composition that exhibits temperature-dependent adhesiveness, can be easily peeled from an adherend, and can suppress the occurrence of contamination due to residue when peeled from the adherend.

[0009] According to the present disclosure, the following transfer stamp material, temperature-sensitive adhesive composition, microtransfer printing device, and transfer printing method are provided: [1] A transfer stamp material used for microtransfer printing, comprising an alkyl group having 10 or more carbon atoms, and a part of the methylene groups in the alkyl group having 10 or more carbon atoms being -O-, -S-, -CO-, -COO-, -OCO-, -NR １Ａ --CO-NR １Ａ -, -NR １Ａ —CO—, —NR １Ａ -CO-NR １Ｂ -, -NR １Ａ —CO—O— or —O—CO—NR １Ａ -substituted group (wherein R １Ａ and R １Ｂ [2] A transfer stamp material containing a polymer (A) having at least one specific group in a side chain, the specific group being at least one selected from the group consisting of an alkyl group having 10 or more carbon atoms and a methylene group in the alkyl group having 10 or more carbon atoms, and each of the specific groups is independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. １Ａ --CO-NR １Ａ -, -NR １Ａ —CO—, —NR １Ａ -CO-NR １Ｂ -, -NR １Ａ —CO—O— or —O—CO—NR １Ａ -substituted group (wherein R １Ａ and R １Ｂa polymer (A) having, at a side chain, a specific group which is at least one selected from the group consisting of (a) and (b) (wherein each group independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms), and a solvent. [3] A microtransfer printing device equipped with a transfer stamp formed from the transfer stamp material of [1] above. [4] A transfer printing method for transferring an element on a source substrate from the source substrate to a predetermined position on a target substrate using the microtransfer printing device of [3] above, the transfer printing method comprising: a step of bringing the transfer stamp into contact with the element and picking up the element with the transfer stamp; and a step of releasing the element picked up by the transfer stamp from the transfer stamp and placing it at the predetermined position, wherein the temperature of the element at the time of release is higher than the temperature at the time of picking up, and the temperature of the element at the time of release is 60°C or higher.

[0010] According to the present disclosure, it is possible to obtain a transfer stamp material, a transfer stamp, and a microtransfer printing device that can form a transfer stamp that can increase the pickup and release speed of elements and suppress the occurrence of contamination due to residue after element transfer. Also, it is possible to obtain a temperature-sensitive adhesive composition that exhibits temperature-dependent adhesiveness, can be easily peeled from an adherend, and can suppress the occurrence of contamination due to residue when peeled from the adherend.

[0011] Fig. 1 is a schematic diagram of a micro-transfer printing device, and Fig. 2 is an explanatory diagram of a micro-transfer printing method.

[0012] Matters related to the embodiments will be described in detail below. In this specification, a numerical range described using "to" means that the numerical values ​​described before and after "to" are included as the lower and upper limits. Unless otherwise specified, each component may be used alone or in combination with two or more components.

[0013] In this specification, the term "hydrocarbon group" includes chain hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. The term "chain hydrocarbon group" refers to a linear hydrocarbon group or a branched hydrocarbon group that does not contain a cyclic structure and is composed solely of a chain structure. However, the chain hydrocarbon group may be saturated or unsaturated. The term "alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic hydrocarbon structure as a ring structure and does not contain an aromatic ring structure. However, the alicyclic hydrocarbon group does not necessarily have to be composed solely of an alicyclic hydrocarbon structure and may also have a chain structure as part of it. The term "aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as a ring structure. However, the aromatic hydrocarbon group does not necessarily have to be composed solely of an aromatic ring structure and may contain a chain structure or an alicyclic hydrocarbon structure as part of it. The term "aromatic ring" includes aromatic hydrocarbon rings and aromatic heterocycles. The term "(meth)acrylo" encompasses both "acrylo" and "methacrylo." "(Meth)acryloxy" is a term that encompasses "acryloxy" and "methacryloxy".

[0014] The "main chain" of a polymer refers to the "trunk" portion of the polymer, which is the longest chain of atoms. It is acceptable for this "trunk" portion to contain a ring structure. For example, "having a specific structure in the main chain" means that the specific structure constitutes a part of the main chain. A "side chain" refers to a portion branched from the "trunk" portion of the polymer. A "structural unit" is typically a repeating unit composed of one monomer. Furthermore, a structural unit may be obtained by reacting a repeating unit having a reactive group with a compound having a functional group capable of reacting with the reactive group.

[0015] <<Transfer Stamp Material>> The transfer stamp material of the present disclosure is a material for forming a transfer stamp used in microtransfer printing. Microtransfer printing is a technique for transferring microelements used in optical integrated circuits, etc., to predetermined positions on a target substrate by transfer printing. The transfer stamp material of the present disclosure contains a polymer having a specific side chain (hereinafter also referred to as "polymer (A)"). Polymer (A) is a thermosensitive polymer that exhibits temperature-dependent adhesive strength due to the specific side chain.

[0016] <Polymer (A)> The polymer (A) is a polymer in which a part of the methylene groups in an alkyl group having 10 or more carbon atoms and an alkyl group having 10 or more carbon atoms are —O—, —S—, —CO—, —COO—, —OCO—, —NR １Ａ --CO-NR １Ａ -, -NR １Ａ —CO—, —NR １Ａ -CO-NR １Ｂ -, -NR １Ａ —CO—O— or —O—CO—NR １Ａ The side chain has at least one group (hereinafter also referred to as "specific group") selected from the group consisting of groups substituted with -. １Ａ and R １Ｂ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms (the same applies hereinafter).

[0017] Here, the phrase "the polymer (A) has a specific group in its side chain" means that a part of the methylene groups in an alkyl group having 10 or more carbon atoms or an alkyl group having 10 or more carbon atoms is -O-, -S-, -CO-, -COO-, -OCO-, -NR １Ａ --CO-NR １Ａ -, -NR １Ａ —CO—, —NR １Ａ -CO-NR １Ｂ -, -NR １Ａ —CO—O— or —O—CO—NR １Ａ The term "a" refers to a group substituted with a heteroatom-containing group such as -, which is bonded to an atom constituting the main chain of the polymer directly or via a divalent linking group. Examples of the divalent linking group include a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, and a group in which a part of the methylene group is -O-, -S-, -CO-, -COO-, -OCO-, -NR １Ａ --CO-NR １Ａ -, -NR １Ａ —CO—, —NR １Ａ -CO-NR １Ｂ -, -NR １Ａ —CO—O— or —O—CO—NR １Ａ Examples of the substituent include a divalent group substituted with -, and groups in which any hydrogen atom of these groups has been substituted. Examples of the substituent include a halogen atom, a hydroxy group, and a carboxy group.

[0018] Regarding the specific group, the alkyl group having 10 or more carbon atoms may be linear or branched. Specific examples of the alkyl group having 10 or more carbon atoms include a decyl group, an undecyl group, a lauryl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a stearyl group, a nonadecyl group, and an eicosyl group. When the specific group is an alkyl group having 10 or more carbon atoms, the number of carbon atoms of the alkyl group is preferably 11 or more, more preferably 12 or more, from the viewpoint that even when the amount of the specific group introduced is reduced, the polymer (A) is less likely to melt when heated during element release, deformation of the transfer stamp material during heating can be suppressed, residue (glue residue) can be suppressed on the element and target substrate after release, and the operation speed during element pickup and release can be increased. Furthermore, the number of carbon atoms of the alkyl group is preferably 30 or less, more preferably 25 or less, from the viewpoint of ease of availability of raw materials.

[0019] The specific group is an alkyl group having 10 or more carbon atoms, and a part of the methylene group is -O-, -S-, -CO-, -COO-, -OCO-, or -NR １Ａ --CO-NR １Ａ -, -NR １Ａ —CO—, —NR １Ａ -CO-NR １Ｂ -, -NR １Ａ —CO—O— or —O—CO—NR １Ａ -substituted group (hereinafter referred to as "group T １ "), the group T １ The heteroatom-containing group is a straight-chain or branched alkyl group having 10 or more carbon atoms, and is preferably a heteroatom-containing group (i.e., -O-, -S-, -CO-, -COO-, -OCO-, -NR １Ａ --CO-NR １Ａ -, -NR １Ａ —CO—, —NR １Ａ -CO-NR １Ｂ -, -NR １Ａ -CO-O-, -O-CO-NR １Ａ -) groups. １ is -O-, -S-, -CO-, -COO-, -OCO-, -NR １Ａ --CO-NR １Ａ-, -NR １Ａ —CO—, —NR １Ａ -CO-NR １Ｂ -, -NR １Ａ —CO—O— or —O—CO—NR １Ａ It is preferable that - substitutes a methylene group in an alkyl group having 10 or more carbon atoms, provided that the - is not adjacent to the methylene group. Of the above, the heteroatom-containing group substituting a part of the methylene group in the alkyl group having 10 or more carbon atoms is preferably -O-. １ is preferably linear.

[0020] Among the above, the specific group is preferably a linear or branched alkyl group having 10 or more carbon atoms, more preferably a linear alkyl group having 10 or more carbon atoms, and even more preferably a linear alkyl group having 10 to 30 carbon atoms, in terms of enabling faster operation speeds at the time of picking up and releasing in transfer printing.

[0021] The amount of the specific group in the polymer (A) is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 25 mol% or more, based on the total amount of structural units contained in the polymer (A), from the viewpoint of enabling an increase in the operation speed during element pickup and release, from the viewpoint of sufficiently suppressing residue during element release, and from the viewpoint of suppressing deformation of the transfer stamp material during heating. Furthermore, the amount of the specific group in the polymer (A) is preferably 90 mol% or less, more preferably 80 mol% or less, and even more preferably 75 mol% or less, based on the total amount of structural units contained in the polymer (A), from the viewpoint of ensuring the adhesive strength of the polymer (A).

[0022] The polymer (A) may further contain an oxiranyl group, an oxetanyl group, or both in addition to the specific group. When the polymer (A) further contains an oxiranyl group, an oxetanyl group, or both, the oxiranyl group or the oxetanyl group can be used as a reactive site to crosslink the polymer (A), thereby increasing the film strength of the transfer stamp material. This further increases the operation speed during element release and enables the production of a transfer stamp material with further reduced adhesive residue. Hereinafter, the oxiranyl group and the oxetanyl group are collectively referred to as "epoxy groups."

[0023] When the polymer (A) has epoxy groups, the amount of epoxy groups in the polymer (A) is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, relative to the total amount of structural units contained in the polymer (A), from the viewpoint of being able to sufficiently enhance the effect of improving the operation speed when releasing the element and being able to enhance the effect of suppressing adhesive residue. Also, from the viewpoint of ensuring the adhesive strength of the polymer (A), the amount of epoxy groups in the polymer (A) is preferably 90 mol% or less, more preferably 80 mol% or less, and even more preferably 75 mol% or less, relative to the total amount of structural units contained in the polymer (A).

[0024] The polymer (A) may further contain a hydroxy group. The polymer (A) further contains a hydroxy group, which allows adjustment of adhesive strength and improves film-forming and moldability when producing a transfer stamp material. Furthermore, by using the hydroxy group as a reactive site to form a crosslinked structure, the film strength of the transfer stamp material can be increased. This allows for a transfer stamp material with a higher operation speed during element release and reduced adhesive residue. It is particularly preferable that the polymer (A) further contains a hydroxy group in addition to the specific group, an oxiranyl group, an oxetanyl group, or both, and a hydroxy group, since this allows for a transfer stamp material with excellent performance (specifically, improved operation speed during element pickup and release, reduced residue during element release, and improved positional accuracy due to reduced deformation of the transfer stamp material).

[0025] When the polymer (A) has hydroxy groups, the amount of the hydroxy groups in the polymer (A) is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, based on the total amount of structural units contained in the polymer (A). The amount of the hydroxy groups in the polymer (A) is preferably 90 mol% or less, more preferably 80 mol% or less, and even more preferably 75 mol% or less, based on the total amount of structural units contained in the polymer (A).

[0026] The polymer (A) preferably has at least one selected from the group consisting of a partial structure represented by the following formula (1-1) and a partial structure represented by the following formula (1-2) in its side chain, from the viewpoints that the polymer (A) having a specific group, an epoxy group, and a hydroxy group in its side chain can be obtained by a simple operation and that the introduction efficiency of the specific group is high. (In formula (1-1) and formula (1-2), X １ and X ２ are each independently —O—, —S—, or —NR ４ -, -CO-, -COO-, -OCO-, -CO-NR ４ -or-NR ４ -CO-. ４ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ２ and R ３ are each independently the above-mentioned specific group. "*" represents a bond.)

[0027] The main chain of the polymer (A) is not particularly limited. In terms of exhibiting good adhesive performance, the polymer (A) is preferably at least one selected from the group consisting of polyorganosiloxanes and addition polymers. Among these, polyorganosiloxanes have a siloxane skeleton in the main chain, which provides excellent thermal decomposition resistance and chemical resistance, high process resistance during the production of the transfer stamp, and excellent durability during repeated use of the transfer stamp.

[0028] (Polyorganosiloxane) When the polymer (A) is a polyorganosiloxane, the specific group is bonded to the atom (preferably silicon atom) constituting the main chain of the polyorganosiloxane directly or via a divalent linking group. As a method for synthesizing a polyorganosiloxane having a specific group in a side chain (hereinafter also referred to as "polyorganosiloxane (A)"), the following method [1a] and method [2a] can be mentioned.

[0029] [1a] A hydrolyzable silane compound (ms-1) having an epoxy group, or a mixture of the silane compound (ms-1) and other silane compounds is hydrolyzed and condensed to synthesize an epoxy group-containing polyorganosiloxane, and then the resulting epoxy group-containing polyorganosiloxane is reacted with a functional group (hereinafter also referred to as "reactive group") and a compound having a specific group (hereinafter also referred to as "reactive compound") [2a] A method of hydrolyzing and condensing a hydrolyzable silane compound (ms-2) having a specific group, or a mixture of the silane compound (ms-2) and other silane compounds. Of these, method [1a] is simple and is preferable in that it can increase the introduction rate of the specific group in the polyorganosiloxane (A). Further, according to method [1a], polyorganosiloxane (A) having epoxy groups and hydroxy groups in the side chain can be obtained by a simple method.

[0030] Specific examples of the silane compound (ms-1) include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-glycidoxyethyltrimethoxysilane, 2-glycidoxyethylmethyldimethoxysilane, 2-glycidoxyethyldimethylmethoxysilane, 2-glycidoxyethyldimethylethoxysilane, 4-glycidoxypropyltrimethoxysilane, 4-glycidoxypropyltriethoxy ... Examples thereof include 4-glycidoxybutyltrimethoxysilane, 4-glycidoxybutylmethyldimethoxysilane, 4-glycidoxybutylmethyldiethoxysilane, 4-glycidoxybutyldimethylmethoxysilane, 4-glycidoxybutyldimethylethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, and 3-(3,4-epoxycyclohexyl)propyltrimethoxysilane.

[0031] Examples of the silane compound (ms-2) include alkoxysilane compounds having the groups exemplified in the description of the specific group. Specific examples of the silane compound (ms-2) include compounds represented by the following formulas (ms-2-1) to (ms-2-6). (In formulas (ms-2-1) to (ms-2-6), R is each independently a methyl group or an ethyl group. The three Rs in the formulas may be the same or different.)

[0032] The other silane compounds used in the synthesis of Method [1a] and Method [2a] are not particularly limited as long as they are hydrolyzable silane compounds. Specific examples thereof include alkoxysilanes such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, and dimethyldiethoxysilane; nitrogen- and sulfur-containing alkoxysilanes such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, mercaptomethyltrimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(3-cyclohexylamino)propyltrimethoxysilane, and N-2-(aminoethyl)-3-aminopropyltrimethoxysilane; Examples of suitable alkoxysilanes include unsaturated hydrocarbon-containing alkoxysilanes such as 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 6-(meth)acryloyloxyhexyltrimethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, and p-styryltrimethoxysilane; and acid anhydride group-containing alkoxysilanes such as trimethoxysilylpropylsuccinic anhydride and triethoxysilylpropylsuccinic anhydride. In addition, in the method [2a], a polyorganosiloxane (A) having an epoxy group on the side chain can be obtained by using a silane compound (ms-1) as the other silane compound.

[0033] The hydrolysis and condensation reaction of silane compounds can be carried out by reacting one or more of the above silane compounds with water, preferably in the presence of a suitable catalyst and organic solvent. The proportion of water used in the reaction is preferably 1 to 30 moles per mole of the total amount of silane compounds. Examples of catalysts include acids, alkali metal compounds, organic bases, titanium compounds, and zirconium compounds. The amount of catalyst used varies depending on the type of catalyst, reaction conditions such as temperature, and can be set appropriately. The amount of catalyst used is preferably 0.01 to 3 moles per total amount of silane compounds. Examples of organic solvents used include hydrocarbons, ketones, esters, ethers, and alcohols. Of these, it is preferable to use a water-insoluble or slightly water-soluble organic solvent. The proportion of organic solvent used is preferably 10 to 10,000 parts by mass per 100 parts by mass of the total amount of silane compounds used in the reaction.

[0034] The hydrolysis and condensation reaction is preferably carried out by heating, for example, in an oil bath. The heating temperature is preferably 130°C or less, and the heating time is preferably 0.5 to 12 hours. After the reaction is complete, the organic solvent layer separated from the reaction solution is dried with a desiccant, if necessary, and then the solvent is removed to obtain the desired polyorganosiloxane. The synthesis method for polyorganosiloxane is not limited to the hydrolysis and condensation reaction described above, and may also be carried out, for example, by reacting a hydrolyzable silane compound in the presence of oxalic acid and alcohol.

[0035] In method [1a], the epoxy group-containing polyorganosiloxane obtained by the above reaction is then reacted with a reactive compound. As a result, the epoxy group of the epoxy group-containing polyorganosiloxane reacts with the reactive group of the reactive compound to obtain a polyorganosiloxane (A) having a specific group and a hydroxy group on the side chain. In addition, by adjusting the amount of epoxy groups in the epoxy group-containing polyorganosiloxane and the amount of the compound having a reactive group, a polyorganosiloxane (A) having an epoxy group on the side chain can be obtained.

[0036] The epoxy group-containing polyorganosiloxane used in the method [1a] preferably has one or both of a cage structure and an incomplete cage structure. When the epoxy group-containing polyorganosiloxane has both a cage structure and an incomplete cage structure, the epoxy group-containing polyorganosiloxane typically has a structure in which the cage structure and the incomplete cage structure are mixed. Specifically, the epoxy group-containing polyorganosiloxane is preferably a polyorganosiloxane containing a structural unit represented by the following formula (S-1): (In formula (S-1), R ６ is a monovalent group having an oxetanyl group or an oxiranyl group.

[0037] In the above formula (S-1), R ６ Examples of the monovalent group represented by the formula (I) include groups having a glycidyl group or a 3,4-epoxycyclohexyl group. Specific examples include a glycidyloxymethyl group, a 2-glycidyloxyethyl group, a 3-glycidyloxypropyl group, a 4-glycidyloxybutyl group, a 2-(3,4-epoxycyclohexyl)ethyl group, a 3-(3,4-epoxycyclohexyl)propyl group, and a 4-(3,4-epoxycyclohexyl)butyl group.

[0038] As the reactive compound, a compound having a carboxy group, a hydroxyl group, an amino group, or a thiol group as a reactive group can be preferably used. From the viewpoint of good reactivity with an epoxy group, among the above, a compound having a specific group and a carboxy group (hereinafter also referred to as "specific carboxylic acid") can be preferably used as the reactive compound.

[0039] Examples of the specific carboxylic acid include carboxylic acids having the groups exemplified in the description of the specific group. Monocarboxylic acids can be preferably used as the specific carboxylic acid. Specific examples of the specific carboxylic acid include saturated fatty acids such as lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecanoic acid, stearic acid, nonadecylic acid, arachidic acid, behenic acid, and lignoceric acid; and carboxylic acids in which a portion of the methylene groups in the alkyl group of these saturated fatty acids are replaced with heteroatom-containing groups. Among these, saturated fatty acids are preferred as the specific carboxylic acid in that they can increase the operation speed during pick-up and release in transfer printing.

[0040] The amount of specific groups in one molecule of polyorganosiloxane (A) is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 25 mol% or more, relative to the silicon atoms of polyorganosiloxane (A), from the viewpoint of sufficiently obtaining the effect of improving the operation speed when picking up and releasing the element, and the effect of suppressing residue and improving positional accuracy when releasing the element. Also, the amount of specific groups in polyorganosiloxane (A) is preferably 90 mol% or less, more preferably 80 mol% or less, and even more preferably 75 mol% or less, relative to the silicon atoms of polyorganosiloxane (A), from the viewpoint of ensuring the adhesive strength of polyorganosiloxane (A).

[0041] When synthesizing polyorganosiloxane (A) by method [1a], the compound having a reactive group used in the reaction with the epoxy group-containing polyorganosiloxane may be only a compound having a specific group, or a compound without a specific group (hereinafter also referred to as "other compound") may be used in combination. The other compound may be any compound that does not have a specific group and has a reactive group, and is not particularly limited. For example, compounds that can be used in combination with the specific carboxylic acid include (meth)acrylic acid, propionic acid, hydroxypropionic acid, etc.

[0042] The amount of other compounds used can be appropriately set within the range that does not impair the effects of the present invention.Specifically, the amount of other compounds used is preferably 20 mol% or less, more preferably 10 mol% or less, and even more preferably 5 mol% or less, based on the total amount of the compounds having reactive groups used in the reaction with epoxy group-containing polyorganosiloxane.

[0043] The reaction between the epoxy group-containing polyorganosiloxane and the reactive compound can be carried out according to standard organic chemistry methods. For example, the reaction between the epoxy group-containing polyorganosiloxane and the carboxylic acid can be preferably carried out in the presence of a catalyst and an organic solvent. Examples of the catalyst used include organic bases and compounds known as curing accelerators that promote the reaction of epoxy compounds (e.g., tertiary organic amines, quaternary organic amines, quaternary ammonium salts, etc.). The amount of catalyst used is preferably 100 parts by mass or less, more preferably 0.1 to 20 parts by mass, per 100 parts by mass of the epoxy group-containing polyorganosiloxane.

[0044] Examples of organic solvents used in the reaction between epoxy group-containing polyorganosiloxane and carboxylic acid include hydrocarbons, ethers, esters, ketones, amides, and alcohols. The organic solvent is preferably used in a proportion such that the solids concentration (the total mass of all components other than the solvent in the reaction solution relative to the total weight of the solution) is 0.1% by mass or greater, more preferably 5 to 50% by mass. In the above reaction, the reaction temperature is preferably 0 to 200°C, more preferably 50 to 150°C. The reaction time is preferably 0.1 to 50 hours, more preferably 0.5 to 20 hours. After completion of the reaction, it is preferable to wash the organic solvent layer separated from the reaction solution with water. After washing with water, the organic solvent layer is dried with an appropriate desiccant, if necessary, and the solvent is then removed to obtain the target polyorganosiloxane (A).

[0045] When the polymer (A) is a polyorganosiloxane, the polymer (A) is preferably a reaction product of a polymer containing a structural unit represented by the above formula (S-1) with a specific carboxylic acid. By reacting a polymer containing a structural unit represented by the above formula (S-1) with a specific carboxylic acid, a polyorganosiloxane (A) having one or both of a cage structure and an incomplete cage structure can be obtained.

[0046] When the polyorganosiloxane (A) is prepared into a 10% by mass solution, it preferably has a solution viscosity of 1 to 500 mPa s, more preferably 3 to 200 mPa s. The polystyrene-equivalent weight average molecular weight (Mw) of the polyorganosiloxane (A) measured by gel permeation chromatography (GPC) is preferably 1,000 to 200,000, more preferably 2,000 to 50,000, and even more preferably 3,000 to 20,000.

[0047] (Addition Polymer) When the polymer (A) is an addition polymer, examples of the addition polymer having a specific group on a side chain (hereinafter also referred to as "addition polymer (A)") include (meth)acrylic polymers, styrene polymers, maleimide polymers, (meth)acrylic-styrene copolymers, (meth)acrylic-maleimide copolymers, (meth)acrylic-styrene-maleimide copolymers, and styrene-maleimide copolymers. In terms of being able to obtain a polymer with higher adhesive strength, the addition polymer (A) preferably contains a structural unit derived from a (meth)acrylic compound.

[0048] The amount of structural units derived from a (meth)acrylic compound in the addition polymer (A) is preferably 50 mol % or more, more preferably 70 mol % or more, and even more preferably 85 mol % or more, based on the total amount of structural units contained in the addition polymer (A).

[0049] In terms of facilitating the introduction of a specific group into the side chain, the addition polymer (A) preferably contains a structural unit derived from a monomer having a specific group (hereinafter also referred to as a "specific monomer"). As the specific monomer, a (meth)acrylic compound can be preferably used from the viewpoint of ensuring adhesive strength while increasing the peeling speed when releasing the element. Specific examples of such a specific monomer include (meth)acrylic acid alkyl esters having an alkyl group having 10 or more carbon atoms, and compounds in which some of the methylene groups in the alkyl group in these (meth)acrylic acid alkyl esters are replaced with heteroatom-containing groups.

[0050] Specific examples of (meth)acrylic acid alkyl esters having an alkyl group having 10 or more carbon atoms include n-decyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, stearyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, behenyl (meth)acrylate, etc. The alkyl group in these (meth)acrylic acid alkyl esters may be linear or branched.

[0051] Examples of compounds in which a part of the methylene groups in the alkyl group in the (meth)acrylic acid alkyl ester is replaced by a heteroatom-containing group include (meth)acrylates such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, n-propoxyethyl (meth)acrylate, n-butoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, n-propoxypropyl (meth)acrylate, n-butoxypropyl (meth)acrylate, methoxybutyl (meth)acrylate, ethoxybutyl (meth)acrylate, n-propoxybutyl (meth)acrylate, and n-butoxybutyl (meth)acrylate. acrylate alkoxyalkyl esters; amino group-containing (meth)acrylic compounds such as dimethylaminomethyl (meth)acrylate, diethylaminomethyl (meth)acrylate, 2-dimethylaminoethyl (meth)acrylate, 2-diethylaminoethyl (meth)acrylate, 2-(di-n-propylamino)ethyl (meth)acrylate, 2-dimethylaminopropyl (meth)acrylate, 2-diethylaminopropyl (meth)acrylate, 2-(di-n-propylamino)propyl (meth)acrylate, 3-dimethylaminopropyl (meth)acrylate, 3-diethylaminopropyl (meth)acrylate, and 3-(di-n-propylamino)propyl (meth)acrylate; etc. Furthermore, as the specific monomer, an amide group-containing vinyl compound can also be used, and specific examples thereof include N,N-dimethyl(meth)acrylamide and N,N-dimethylaminopropyl(meth)acrylamide.

[0052] Among the above-mentioned specific monomers, in terms of enabling faster operation speeds at the time of picking up and releasing in transfer printing, the specific monomer is preferably a (meth)acrylic acid alkyl ester having an alkyl group having 10 or more carbon atoms, more preferably a (meth)acrylic acid alkyl ester having an alkyl group having 10 to 30 carbon atoms, and even more preferably a (meth)acrylic acid alkyl ester having an alkyl group having 10 to 25 carbon atoms.

[0053] When synthesizing the addition polymer (A), a monomer having no specific group (hereinafter also referred to as "other monomer") may be used together with the specific monomer. The other monomer may be any monomer having no specific group and capable of copolymerizing with the specific monomer. Examples of the other monomer include (meth)acrylic compounds, styrene compounds, conjugated diene compounds, and maleimide compounds.

[0054] Specific examples of other monomers include (meth)acrylic compounds such as unsaturated carboxylic acids such as (meth)acrylic acid; (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; epoxy group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, 3,4-epoxycyclohexylmethyl (meth)acrylate, and (3-ethyloxetan-3-yl)methyl (meth)acrylate; (meth)acrylic acid hydroxyalkyl esters such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; and (meth)acrylic acid cycloalkyl esters such as cycloalkyl (meth)acrylate. (meth)acrylic acid aromatic esters such as benzyl (meth)acrylate; silyl group-containing (meth)acrylic acid esters such as trimethoxysilylpropyl (meth)acrylate, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 6-(meth)acryloyloxyhexyltrimethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, and 3-(meth)acryloxypropylmethyldiethoxysilane; (meth)acrylonitrile; and the like.

[0055] Examples of styrene compounds include styrene, methylstyrene, divinylbenzene, 4-hydroxymethylstyrene, p-styryltrimethoxysilane, 4-(glycidyloxymethyl)styrene, and vinylbenzoic acid. Examples of conjugated diene compounds include 1,3-butadiene and 2-methyl-1,3-butadiene. Examples of maleimide compounds include N-methylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-(4-glycidyloxyphenyl)maleimide, N-(4-glycidyloxymethylphenyl)maleimide, N-glycidylmaleimide, N-(4-carboxyphenyl)maleimide, and N-(4-tert-butoxycarbonylphenyl)maleimide.

[0056] The amount of the structural units derived from the specific monomer in the addition polymer (A) is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 25 mol% or more, relative to the total amount of structural units contained in the addition polymer (A), from the viewpoints of sufficiently increasing the operation speed during element pickup and release, suppressing residue (glue residue) after element release, and suppressing deformation of the transfer stamp material due to heating to improve positional accuracy during element release. Furthermore, the amount of the structural units derived from the specific monomer in the addition polymer (A) is preferably 90 mol% or less, more preferably 80 mol% or less, and even more preferably 70 mol% or less, relative to the total amount of structural units contained in the addition polymer (A), from the viewpoint of ensuring the adhesive strength of the addition polymer (A).

[0057] When the addition polymer (A) further contains epoxy groups, the epoxy groups are used as reactive sites to increase film strength, thereby further increasing the operation speed during element release and further suppressing residue after element release, which is preferable. When the addition polymer (A) contains epoxy groups, the amount of epoxy groups in the addition polymer (A) is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, based on the total amount of structural units contained in the addition polymer (A), from the viewpoint of sufficiently achieving the effects of increasing the operation speed during element release and suppressing residue. Furthermore, the amount of epoxy groups in the addition polymer (A) is preferably 60 mol% or less, more preferably 40 mol% or less, and even more preferably 30 mol% or less, based on the total amount of structural units contained in the addition polymer (A), from the viewpoint of ensuring the adhesive strength of the addition polymer (A).

[0058] When the addition polymer (A) further contains hydroxy groups, the adhesive strength can be adjusted, thereby improving the film-forming and moldability when producing a transfer stamp material. Furthermore, by using hydroxy groups as reaction sites, the film strength of the transfer stamp material can be further increased. This further increases the operation speed when releasing the element, and enables the production of a transfer stamp material with further reduced adhesive residue. When the addition polymer (A) contains hydroxy groups, the amount of hydroxy groups in the addition polymer (A) is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, relative to the total amount of structural units contained in the addition polymer (A). Furthermore, the amount of hydroxy groups in the addition polymer (A) is preferably 40 mol% or less, more preferably 30 mol% or less, and even more preferably 20 mol% or less, relative to the total amount of structural units contained in the addition polymer (A).

[0059] The addition polymer (A) can be obtained, for example, by polymerizing the monomers in the presence of a polymerization initiator. The polymerization initiator used is preferably an azo compound such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), or 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile). The proportion of the polymerization initiator used is preferably 0.01 to 30 parts by mass per 100 parts by mass of all the monomers used in the reaction.

[0060] The polymerization reaction is preferably carried out in an organic solvent. Examples of organic solvents used in the reaction include alcohols, ethers, ketones, amides, esters, and hydrocarbons. Ethers such as diethylene glycol ethyl methyl ether and esters such as propylene glycol monomethyl ether acetate are preferred. The reaction temperature is preferably 30 to 120°C, and the reaction time is preferably 1 to 36 hours. The amount of organic solvent used is preferably such that the total amount of monomers used in the reaction is 0.1 to 60% by mass relative to the total amount of the reaction solution. The addition polymer (A) can also be obtained by synthesizing an addition polymer having an epoxy group in the side chain, and then reacting the resulting epoxy-group-containing addition polymer with a specific carboxylic acid.

[0061] The polystyrene-equivalent weight average molecular weight (Mw) of the addition polymer (A) measured by GPC is preferably 250 to 500,000, and more preferably 500 to 100,000. The molecular weight distribution (Mw / Mn), which is expressed as the ratio of Mw to the polystyrene-equivalent number average molecular weight (Mn) measured by GPC, is preferably 8 or less, and more preferably 6 or less.

[0062] <Other Components> The transfer stamp material of the present disclosure may consist solely of polymer (A), or may further contain, together with polymer (A), a component (other component) different from polymer (A). The other components are not particularly limited as long as they do not impair the effects of the present invention. Examples of other components include a polymer having no specific group (hereinafter also referred to as "polymer (B)"), an antioxidant, a metal chelate compound, a surfactant, a filler, a dispersant, a colorant, a softener, a plasticizer, an adhesive aid, and an ultraviolet absorber. The content of the other components in the transfer stamp material can be appropriately selected depending on each compound, as long as the effects of the present invention are not impaired.

[0063] (Polymer (B)) The polymer (B) need not have a specific group, and its main chain is not particularly limited. Examples of the polymer (B) include polyamic acid, polyimide, polyamic acid ester, polyamide, polyurea, polyorganosiloxane, polyester, cellulose derivative, polyacetal, addition polymer, polyether, polyurethane, etc. Examples of the addition polymer include (meth)acrylic polymer, styrene polymer, maleimide polymer, (meth)acrylic-styrene copolymer, (meth)acrylic-maleimide copolymer, (meth)acrylic-styrene-maleimide copolymer, and styrene-maleimide copolymer, etc.

[0064] Among these, polymers (B) having a different type of main chain skeleton from polymer (A) can be preferably used. Specifically, polymer (B) is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyamide, and addition polymer, more preferably at least one selected from the group consisting of polyamic acid, polyimide, and addition polymer. For example, when polymer (A) is polyorganosiloxane (A), polymer (B) is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyamide, and addition polymer, more preferably at least one selected from the group consisting of polyamic acid, polyimide, and addition polymer. When polymer (A) is addition polymer (A), polymer (B) is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, and polyamide, more preferably at least one selected from the group consisting of polyamic acid and polyimide. Known monomers can be used as appropriate as the monomer constituting polymer (B).

[0065] As the polymer (B), a polymer having a carboxy group can be preferably used. When the polymer (B) has a carboxy group, the operation speed during element release can be increased. Furthermore, by using the carboxy group as a reactive site, the generation of residue during element release can be further suppressed and the positional accuracy of transfer can be further improved. From the viewpoint of fully obtaining these effects, it is more preferable that the polymer (B) contains a structural unit having a carboxy group.

[0066] In the polymer (B), the content of the structural unit having a carboxy group is preferably 2 mol % or more, more preferably 5 mol % or more, and even more preferably 10 mol % or more, based on the total amount of structural units contained in the polymer (B).

[0067] When the polymer (B) is contained in the transfer stamp material, the content of the polymer (B) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the total amount of the polymer (A) and the polymer (B). The content of the polymer (B) is preferably 90 parts by mass or less, more preferably 85 parts by mass or less, per 100 parts by mass of the total amount of the polymer (A) and the polymer (B).

[0068] The transfer stamp material of the present disclosure may be a film or a sheet. A known method for forming a thin film can be appropriately adopted as a method for producing a film- or sheet-shaped transfer stamp material. The film- or sheet-shaped transfer stamp material can be produced, for example, by applying a liquid composition in which the polymer (A) is dissolved or dispersed in a solvent onto a substrate and removing the solvent from the liquid composition on the substrate. A liquid composition in which the polymer (A) is dissolved or dispersed in a solvent is preferred because it allows for the easy formation of a thin film with a uniform thickness.

[0069] Examples of substrates that can be used include glass substrates such as float glass and soda glass; and substrates made of resins such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, poly(alicyclic olefin), polyimide, and triacetyl cellulose. The liquid composition can be applied to the substrate surface by any suitable application method. Examples of suitable methods include roll coating, spin coating, inkjet printing, offset printing, flexographic printing, bar coating, extrusion die, direct gravure coating, chamber doctor coating, offset gravure coating, single-roll kiss coating, reverse kiss coating using a small-diameter gravure roll, three-roll reverse coating, four-roll reverse coating, slot die coating, air doctor coating, forward rotation roll coating, blade coating, knife coating, impregnation coating, MB coating, and MB reverse coating.

[0070] After applying the liquid composition to the substrate surface, the applied surface may be heated (baked) to form a coating film. Preheating (pre-baking) is preferably performed to prevent dripping of the applied liquid composition. The pre-baking temperature is preferably 30 to 150°C, and the pre-baking time is preferably 0.25 to 10 minutes. A baking (post-baking) step is then performed to thoroughly remove the solvent from the applied liquid composition. The baking temperature (post-baking temperature) is preferably 80 to 270°C, more preferably 80 to 250°C. The post-baking time is preferably 5 to 200 minutes. The thickness of the film thus formed is preferably 0.05 to 50 μm.

[0071] Here, in microtransfer printing, the transfer stamp material preferably has temperature-dependent and moving-speed-dependent adhesive strength. Regarding the temperature-dependent adhesive strength, the main material (polymer) of the transfer stamp material is preferably one that exhibits sufficiently high adhesive strength at temperatures below the softening point (thermal relaxation of the polymer) of the polymer and exhibits fluidity at temperatures above the softening point, thereby decreasing adhesive strength. In other words, it is desirable to select a material whose adhesive strength changes significantly before and after the softening point of the polymer. Adjusting the adhesive strength of the material can be achieved, for example, by adjusting one or more of the following: the type of resin in the surface layer of the transfer stamp material, the structure of the resin side chain, the composition and blending ratio of components other than the resin, etc. Furthermore, adhesive strength generally depends on peeling conditions (peel angle, moving speed), and therefore, in order to control adhesive strength, it is considered important to design adhesive strength at an appropriate moving speed. In order to increase the throughput of microtransfer printing, it is generally preferable to design a material that exhibits adhesiveness that allows the microelements to be picked up at a pickup speed of, for example, 1000 μm / s or more in the pickup process, and to design a material that allows the microelements to be released at a release speed of 10 μm / s or more (more preferably 100 μm / s or more) in the release process.

[0072] In this regard, transfer stamp materials containing polymer (A) exhibit temperature dependence of adhesive strength (specifically, temperature dependence due to the softening point of the transfer stamp material containing polymer (A)) and movement speed dependence (specifically, movement speed dependence due to dynamic viscoelasticity). More specifically, with regard to the temperature dependence of adhesive strength, transfer stamp materials formed from polymer (A) or a temperature-sensitive adhesive composition containing polymer (A) have a softening point due to thermal relaxation of the polymer, and exhibit sufficiently high adhesive strength at temperatures below the softening point, while exhibiting fluidity at temperatures above the softening point, thereby decreasing adhesive strength. With regard to the movement speed dependence of adhesive strength, due to the dynamic viscoelasticity of the transfer stamp material, when the transfer stamp material is quickly separated from the adhesive interface with the element, the adhesive strength of the transfer stamp material becomes sufficiently large to pick up the element from the source substrate. Conversely, when the transfer stamp material is slowly separated from the adhesive interface with the element, the adhesive strength of the transfer stamp material becomes sufficiently small to release the element. As described above, the transfer stamp material of the present disclosure adheres to a transfer target element at or below a first temperature, and picks up the element when the transfer stamp is moved at or above a first moving speed. Furthermore, the element is released by moving the transfer stamp at or above a second temperature higher than the first temperature at a second moving speed equal to or lower than the first moving speed. Note that the above mechanism of action is merely speculation and does not limit the present invention in any way.

[0073] In particular, the transfer stamp material disclosed herein has a small temperature difference ΔT between the first temperature and the second temperature, e.g., 50°C or less. A transfer stamp formed from a transfer stamp material exhibiting such unique temperature sensitivity can switch between an adhesive state and a non-adhesive state with respect to a transfer target with a relatively small temperature change. This improves workability when mass-producing optical integrated circuits by picking up and releasing the transfer target using a transfer printing method, and also enables faster transfer integration. Transfer targets can be various elements (e.g., semiconductor lasers, amplifiers, optical switches, optical modulators, photodetectors, resistors, capacitors, transistors, and other functional elements, as well as micro-LEDs) that are sized on the order of millimeters to nanometers and are used to construct optical integrated circuits and semiconductor chips.

[0074] When transferring elements using the transfer stamp material of the present disclosure, it is preferable to set the second temperature (i.e., the temperature when releasing the microelement) higher than the first temperature (i.e., the temperature when picking up the microelement). From the viewpoint of improving productivity during the manufacture of optical integrated circuits and protecting the elements, the first temperature (i.e., the temperature when picking up the microelement) is preferably 60°C or lower, more preferably less than 60°C, even more preferably 50°C or lower, and even more preferably 40°C or lower. Furthermore, the second temperature (i.e., the temperature when releasing the microelement) is preferably 60°C or higher, more preferably 65 to 100°C, and even more preferably 65 to 90°C.

[0075] <Micro Transfer Printing Apparatus and Transfer Printing Method> The micro transfer printing apparatus of the present disclosure includes a transfer stamp formed from the transfer stamp material of the present disclosure. Figure 1 shows a schematic configuration of the micro transfer printing apparatus of the present disclosure. As shown in Figure 1, the micro transfer printing apparatus 10 includes a transfer stamp 11 provided at the bottom of the apparatus and a control unit 12 that controls the operation of the transfer stamp 11.

[0076] The transfer stamp 11 includes a support portion 13 and a stamp portion 14. The support portion 13 is made of glass or resin and supports the stamp portion 14. The stamp portion 14 is disposed on the underside of the support portion 13. Specifically, the stamp portion 14 includes a fixed portion 14A disposed adjacent to the support portion 13 at the upper portion of the stamp portion 14, and an adhesive portion 14B disposed adjacent to the fixed portion 14A at the lower portion of the stamp portion 14. The fixed portion 14A is a member that supports and fixes the adhesive portion 14B, and is, for example, double-sided tape, adhesive, or adhesive film. The adhesive portion 14B is formed from a transfer stamp material containing a polymer (A). The details of the transfer stamp material are as described above. The size and shape of the underside of the adhesive portion 14B correspond to the size and shape of the microelement 20 (see FIG. 2), which is the transfer target. Note that the adhesive portion 14B may be formed directly on the underside of the support portion 13 without providing the fixed portion 14A.

[0077] When the microelement 20 on the source substrate 21 is transferred to a target position on the target substrate 22 using the micro transfer printing device 10, the method includes the following pick-up step and release step. Pick-up step: The transfer stamp 11 is brought into contact with the microelement 20 on the source substrate 21, and the microelement 20 is picked up by the transfer stamp 11. Release step: The microelement 20 picked up by the transfer stamp 11 is released from the transfer stamp 11 and placed at the target position on the target substrate 22.

[0078] (Pickup Process) In the pickup process, first, the control unit 12 moves the transfer stamp 11 to a position facing the microelement 20 on the source substrate 21, and moves the transfer stamp 11 downward (see FIGS. 1 and 2(a)). This brings the lower surface of the stamp portion 14 (more specifically, the lower surface of the adhesive portion 14B) into contact with the upper surface of the microelement 20, bonding the lower surface of the stamp portion 14 to the upper surface of the microelement 20 (see FIG. 2(b)). After contacting the stamp portion 14 with the microelement 20, the control unit 12 moves the transfer stamp 11 upward, and the microelement 20 is picked up (see FIG. 2(c)). The temperature (e.g., the temperature of the source substrate 21) when picking up the microelement 20 is preferably 60°C or lower. A temperature control unit 23 for heating the source substrate 21 is provided below the source substrate 21 (see FIG. 2(a)). The temperature control unit 23 is, for example, a hot plate. When heating the source substrate 21 to a temperature above room temperature, the temperature can be adjusted by the temperature control unit 23. As a mode for controlling the temperature during element pickup, a temperature control means may be provided in one or both of the control unit 12 and the support unit 13, instead of or together with the temperature control unit 23, and the pickup temperature may be controlled by the temperature control means. As the source substrate 21, for example, a silicon wafer, a GaAs wafer, or a thin film containing an inorganic semiconductor material (e.g., silicon, InAlP, InP, GaAs, InGaAs, AlGaAs, etc.) may be used.

[0079] (Release Process) In the subsequent release process, the transfer stamp 11, with the microelement 20 adhered to the underside of the stamp portion 14, is moved by the control portion 12 to a position facing the target position on the target substrate 22, and the transfer stamp 11 is moved downward to place the microelement 20 at the target position on the target substrate 22 (see FIG. 2(d)). Below the target substrate 22, a temperature control portion 24 is provided to heat the target substrate 22. The temperature control portion 24 is, for example, a hot plate.

[0080] In the release process, the target substrate 22 is heated by the temperature control unit 24 at one or more timings before, during, and after the placement of the microelement 20 on the target substrate 22 (see FIG. 2(d)). When the stamp unit 14 is heated by a heat treatment performed by the temperature control unit 24 while the microelement 20 is adhered to the underside of the stamp unit 14, the adhesion at the interface between the stamp unit 14 and the microelement 20 decreases. Furthermore, the transfer stamp 11 is moved upward by the control unit 12, releasing the microelement 20 from the stamp unit 14 (see FIG. 2(e)). This transfers the microelement 20 to the target position on the target substrate 22 (see FIGS. 2(e) and 2(f)). In the transfer stamp 11 of this embodiment, the adhesive portion 14B is formed from a transfer stamp material containing the polymer (A), and therefore the adhesive portion 14B is less likely to deform when heated during release. This allows the microelement 20 to be transferred to the target position with high positional accuracy. As in the case of element pickup, a mode of controlling the temperature during element release may be such that a temperature control means is provided in one or both of the control unit 12 and the support unit 13 in place of or together with the temperature control unit 24, and the release temperature is controlled by the temperature control means. Also, the temperature control units 23 and 24 may be the same.

[0081] The temperature when releasing the microelement 20 (e.g., the temperature of the target substrate 22) is preferably 60°C or higher. The target substrate 22 may be, for example, an optical circuit substrate (a substrate made of silicon, SOI, GaAs, InP, SiN, SiC, AlN, LN, or the like). The operation speed (release speed) of the transfer stamp 11 when separating the transfer stamp 11 from the target substrate 22 to release the microelement 20 may be the same as or different from the operation speed (pickup speed) of the transfer stamp 11 when separating the transfer stamp 11 from the source substrate 21 to pick up the microelement 20. From the viewpoint of optimally picking up and releasing the microelement 20, it is preferable to set the pickup speed to the first movement speed and the release speed to a second movement speed that is the same as or slower than the first movement speed.

[0082] According to the transfer stamp 11 in which the stamp portion 14 is formed using a transfer stamp material containing polymer (A), the operation speed when picking up the microelement 20 (pickup speed) and the operation speed when releasing it (release speed) are fast, contamination due to glue residue on the target substrate 22 after the microelement 20 is transferred is suppressed, and high positional accuracy can be ensured when transferring the microelement 20 onto the target substrate 22.

[0083] <<Thermosensitive Adhesive Composition>> Next, the thermosensitive adhesive composition of the present disclosure will be described. The thermosensitive adhesive composition of the present disclosure is a polymer composition for forming an adhesive layer whose adhesive strength changes depending on temperature. The thermosensitive adhesive composition of the present disclosure contains the above-mentioned polymer (A) and a solvent. Details of specific examples and preferred examples of the polymer (A) and the solvent are the same as those described for the transfer stamp material.

[0084] The thermosensitive adhesive composition of the present disclosure may further contain components (other components) other than the polymer (A) and the solvent. The other components can be appropriately selected depending on the application of the adhesive layer formed from the thermosensitive adhesive composition of the present disclosure. Examples of the other components include the polymer (B), a crosslinking agent, a thermal polymerization initiator, a photopolymerization initiator, an antioxidant, a metal chelate compound, a curing accelerator, a surfactant, a filler, a dispersant, a photosensitizer, a colorant, a softener, a plasticizer, an adhesive aid, and an ultraviolet absorber. The content of the other components can be appropriately selected depending on each compound as long as the effects of the present invention are not impaired.

[0085] (Crosslinking Agent) The thermosensitive adhesive composition of the present disclosure may further contain a crosslinking agent. When the thermosensitive adhesive composition contains a crosslinking agent together with the polymer (A), the operation speed during element release can be further increased. Furthermore, when the thermosensitive adhesive composition further contains a crosslinking agent, residue during element release can be further suppressed and the positional accuracy of transfer can be further improved. In particular, when the polymer (A) has one or both of an epoxy group and a hydroxy group, this is preferable in that the operation speed during element release can be further increased and residue can be further suppressed.

[0086] The crosslinking agent preferably has two or more crosslinkable groups per molecule that can react with the reactive groups in the polymer (A) to form a covalent bond. As the crosslinking agent, a compound having two or more crosslinkable groups per molecule, each of which is at least one type of crosslinkable group selected from the group consisting of an oxiranyl group, an oxetanyl group, a cyclic carbonate group, a hydroxy group, a protected hydroxy group, a carboxy group, a protected carboxy group, a mercapto group, a protected mercapto group, an amino group, a protected amino group, an isocyanate group, a protected isocyanate group, and a polymerizable carbon-carbon unsaturated bond group, can be preferably used.

[0087] From the viewpoints of increasing the operation speed at the time of device release, suppressing the formation of residues, and sufficiently increasing the positional accuracy, the number of crosslinkable groups that the crosslinking agent has in one molecule is preferably 2 to 10, and more preferably 2 to 6. The molecular weight of the crosslinking agent is preferably 100 to 1,000, more preferably 100 to 800, and even more preferably 100 to 600.

[0088] Specific examples of crosslinking agents include compounds having an oxiranyl group or an oxetanyl group, such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, triglycidyl isocyanurate, glycerol polyglycidyl ether, pentaerythritol tetraglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, N,N,N',N'-tetraglycidyl glycoluril, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, and 2,2-dibromoneo. Examples thereof include pentyl glycol diglycidyl ether, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N-diglycidyl-benzylamine, N,N-diglycidyl-aminomethylcyclohexane, N,N-diglycidyl-cyclohexylamine, 1,3-bis(oxiran-2-ylmethoxy)-2,2-bis[(oxiran-2-ylmethoxy)methyl]propane, and epoxidation reaction products of 2,2'-diallylbisphenol A diallyl ether with hydrogen peroxide.

[0089] Examples of the compound having a cyclic carbonate group include compounds represented by the following formulas (d1-1) and (d1-2).

[0090] As the compound having a hydroxy group or a protected hydroxy group, a compound having a methylol group, a protected methylol group, a hydroxyalkylamide group, or a protected hydroxyalkylamide group can be preferably used. Specific examples of these include compounds represented by the following formulas (d2-1) to (d2-6) and (d3-1) to (d3-8).

[0091] Examples of compounds having a carboxy group or a protected carboxy group include maleic acid, itaconic acid, trimellitic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, cis-1,2,3,4-tetrahydrophthalic acid, 2-carboxylato-2-hydroxy-1,3-propanedicarboxylic acid, ethylene glycol bistrimellitate, propylene glycol bistrimellitate, and 4,4'-oxydiphthalic acid.

[0092] Examples of compounds having a mercapto group or a protected mercapto group include 1,2-ethanedithiol, 1,3-propanedithiol, 1,3,4-thiadiazole-2,5-dithiol, 1,10-decanedithiol, pentaerythritol tetrakis(3-mercaptobutyrate), and 1,3,5-tris(2-(3-sulfanylbutanoyloxy)ethyl)-1,3,5-triazinane-2,4,6-trione.

[0093] Examples of the compound having an amino group or a protected amino group include compounds represented by the following formulas (d4-1) to (d4-5).

[0094] Examples of compounds having an isocyanate group include tolylene diisocyanate, xylylene diisocyanate, chlorophenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, etc. Examples of compounds having a protected isocyanate group include compounds in which the isocyanate group in a compound having an isocyanate group is protected with 3,6-dimethylpyrazole, methyl ethyl ketoxime, diethyl malonate, or ε-caprolactam, and compounds represented by the following formula (d5-1):

[0095] Examples of the compound having a group having a polymerizable carbon-carbon bond include compounds having a (meth)acryloyl group, a maleimide group, an alkenyl group, a vinylphenyl group, a vinyl ether group, or a 3-methylenetetrahydrofuran-2(3H)-one-5-yl group. Specific examples of these include ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, pentaerythritol tri(meth)acrylate, and compounds represented by the following formulas (d6-1) to (d6-8).

[0096] (In formula (d2-5), Ac is an acetyl group.)

[0097] Among the above crosslinking agents, a compound having two or more crosslinkable groups in one molecule, each of which is at least one type selected from the group consisting of an oxiranyl group, an oxetanyl group, a carboxy group, a protected carboxy group, an amino group, a protected amino group, and a protected isocyanate group, is preferred, and a compound having two or more crosslinkable groups in one molecule, each of which is at least one type selected from the group consisting of a carboxy group, a protected carboxy group, an amino group, and a protected amino group, is more preferred, in terms of being able to increase the operation speed during element release, and further improve the effect of suppressing residues and positional accuracy.

[0098] As the crosslinking agent, a compound without an aromatic ring (hereinafter also referred to as an "aliphatic crosslinking agent") can be preferably used, since it can clearly show the change in adhesive strength with respect to temperature change while maintaining the adhesiveness of the transfer stamp material. The aliphatic crosslinking agent may be a compound having a chain structure or may have a cyclic structure. Specific examples of the aliphatic crosslinking agent include the compounds exemplified above that do not have an aromatic ring.

[0099] When the thermosensitive adhesive composition contains a crosslinking agent, the content of the crosslinking agent is preferably 0.1 parts by mass or more relative to 100 parts by mass of the total amount of polymer components contained in the thermosensitive adhesive composition (i.e., the total amount of polymer (A) and polymer (B)), from the viewpoint of sufficiently achieving the effect of increasing the operation speed when releasing the element. The content of the crosslinking agent is more preferably 0.5 parts by mass or more, and even more preferably 1 part by mass or more, relative to 100 parts by mass of the total amount of polymer components. Furthermore, from the viewpoint of ensuring the adhesiveness of the transfer stamp material, the content of the crosslinking agent is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, relative to 100 parts by mass of the total amount of polymer components.

[0100] (Solvent) The heat-sensitive adhesive composition of the present disclosure may be provided as a liquid composition in which the polymer (A) is dissolved or dispersed in a solvent. As the solvent, a solvent capable of dissolving or dispersing the polymer (A) can be appropriately used. Specific examples of the solvent include water, an organic solvent, and a mixed solvent thereof.

[0101] Examples of the organic solvent to be used include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, phenol, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol, 1-hexanol, 2-hexanol, propane-1,2-diol, 3-methoxy-1-butanol, ethylene glycol monomethyl ether, methyl lactate, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl acetoacetate, ethyl acetoacetate, ethyl propionate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, and ethylene glycol-i-propyl ether. Examples of the alkyl ether include diethyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate, propylene carbonate, propylene glycol monomethyl ether (PGME), diethylene glycol diethyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol diacetate, cyclopentanone, and cyclohexanone.

[0102] The solids concentration of the thermosensitive adhesive composition of the present disclosure (the proportion of the total mass of components other than the solvent to the total mass of the composition) can be appropriately selected taking into consideration the viscosity of the composition, the volatility of the solvent, the intended use of the composition, etc. The solids concentration of the thermosensitive adhesive composition of the present disclosure is, for example, 3 to 60 mass % from the viewpoint of forming an adhesive layer with sufficiently high adhesive strength. The temperature during preparation of the composition is, for example, 0 to 60°C.

[0103] When forming an adhesive layer using the temperature-sensitive adhesive composition of the present disclosure, the adhesive layer can be formed according to a known method. For example, an adhesive layer of a desired thickness can be formed by applying the temperature-sensitive adhesive composition to a substrate and removing the solvent. For details of the method for forming the adhesive layer, the description of the method for forming a thin film as a transfer stamp material can be cited.

[0104] The adhesive layer formed from the temperature-sensitive adhesive composition of the present disclosure exhibits temperature dependence of adhesive strength. Such a composition can be used in various applications. Specifically, the composition is useful as a material for forming an adhesive layer in various applications such as optical applications, display applications, and semiconductor applications.

[0105] According to the present disclosure, there are provided a transfer stamp material, a temperature-sensitive adhesive composition, a microtransfer printing device, and a transfer printing method, each of which has the following specific embodiments: [1] A transfer stamp material used in microtransfer printing, which comprises an alkyl group having 10 or more carbon atoms and a methylene group in the alkyl group having 10 or more carbon atoms, and which is selected from the group consisting of -O-, -S-, -CO-, -COO-, -OCO-, -NR １Ａ --CO-NR １Ａ -, -NR １Ａ —CO—, —NR １Ａ -CO-NR １Ｂ -, -NR １Ａ —CO—O— or —O—CO—NR １Ａ -substituted group (wherein R １Ａ and R １Ｂand each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms). [2] The transfer stamp material according to [1], wherein the polymer (A) further comprises an oxiranyl group, an oxetanyl group, or both of these. [3] The transfer stamp material according to [1] or [2], wherein the polymer (A) further comprises a hydroxy group. [4] The transfer stamp material according to any one of [1] to [3], wherein the polymer (A) further comprises an oxiranyl group, an oxetanyl group, or both of these, and a hydroxy group. [5] The transfer stamp material according to any one of [1] to [4], wherein the polymer (A) is at least one selected from the group consisting of polyorganosiloxanes and addition polymers. [6] The transfer stamp material according to any one of [1] to [5], wherein the polymer (A) is a polyorganosiloxane having one or both of a cage structure and an incomplete cage structure. [7] The transfer stamp material according to any one of [1] to [6], wherein the polymer (A) has at least one selected from the group consisting of the partial structure represented by the above formula (1-1) and the partial structure represented by the above formula (1-2) in its side chain. [8] The transfer stamp material according to any one of [1] to [7], wherein the polymer (A) is a reaction product of a polymer containing a structural unit represented by the above formula (S-1) and a carboxylic acid having the specific group. [9] The transfer stamp material according to any one of [1] to [8], wherein the polymer (A) is crosslinked.

[10] The transfer stamp material according to any one of [1] to [9], further comprising a polymer (B) having no specific group.

[11] The transfer stamp material according to

[10] , wherein the polymer (B) has a carboxy group.

[12] The transfer stamp material according to

[10] or

[11] , wherein the polymer (A) and the polymer (B) have different main chain skeletons.

[13] A temperature-sensitive adhesive composition for forming an adhesive layer whose adhesive strength changes depending on temperature, wherein the alkyl group having 10 or more carbon atoms and a part of the methylene groups in the alkyl group having 10 or more carbon atoms are -O-, -S-, -CO-, -COO-, -OCO-, -NR １Ａ --CO-NR １Ａ -, -NR １Ａ —CO—, —NR １Ａ-CO-NR １Ｂ -, -NR １Ａ —CO—O— or —O—CO—NR １Ａ -substituted group (wherein R １Ａ and R １Ｂand each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms), and a solvent.

[14] The temperature-sensitive adhesive composition according to

[13] , wherein the polymer (A) is a polyorganosiloxane.

[15] The temperature-sensitive adhesive composition according to

[14] , wherein the polyorganosiloxane has one or both of a cage structure and an incomplete cage structure.

[16] The temperature-sensitive adhesive composition according to any one of

[13] to

[15] , wherein the polymer (A) further has an oxiranyl group, an oxetanyl group, or both.

[17] The temperature-sensitive adhesive composition according to any one of

[13] to

[16] , wherein the polymer (A) further has a hydroxy group.

[18] The thermosensitive adhesive composition according to any one of

[13] to

[17] , wherein the polymer (A) has at least one selected from the group consisting of the partial structure represented by the above formula (1-1) and the partial structure represented by the above formula (1-2) in a side chain.

[19] The thermosensitive adhesive composition according to any one of

[13] to

[18] , wherein the polymer (A) is a reaction product of a polymer containing a structural unit represented by the above formula (S-1) and a carboxylic acid having the specific group.

[20] The thermosensitive adhesive composition according to any one of

[13] to

[19] , further comprising a crosslinking agent.

[21] The heat-sensitive adhesive composition according to

[20] , wherein the crosslinking agent has, in one molecule, a total of two or more of at least one selected from the group consisting of an oxiranyl group, an oxetanyl group, a cyclic carbonate group, a hydroxy group, a protected hydroxy group, a carboxy group, a protected carboxy group, a mercapto group, a protected mercapto group, an amino group, a protected amino group, an isocyanate group, a protected isocyanate group, and a polymerizable carbon-carbon unsaturated bond group.

[22] The heat-sensitive adhesive composition according to any one of

[13] to

[21] , further comprising a polymer (B) having no specific group.

[23] The heat-sensitive adhesive composition according to

[22] , wherein the polymer (B) has a carboxy group.

[24] The heat-sensitive adhesive composition according to

[22] or

[23] , wherein the main chain skeletons of the polymer (A) and the polymer (B) are different.

[25] A micro-transfer printing device comprising a transfer stamp formed from the transfer stamp material according to any one of [1] to

[12] .

[26] A transfer printing method for transferring an element on a source substrate from the source substrate to a predetermined position on a target substrate using the micro-transfer printing device according to

[25] , the transfer printing method comprising the steps of bringing the transfer stamp into contact with the element and picking up the element with the transfer stamp, and releasing the element picked up by the transfer stamp from the transfer stamp and placing it at the predetermined position, wherein the temperature of the element when picked up is less than 60°C and the temperature of the element when released is 60°C or higher.

[0106] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. In the following examples, "parts" and "%" are by mass unless otherwise specified.

[0107] In the following examples, the weight average molecular weight (Mw) and number average molecular weight (Mn) of a polymer were measured by the following method. <Mw and Mn of Polymer> The weight average molecular weight (Mw) and number average molecular weight (Mn) were measured by gel permeation chromatography (GPC) under the following conditions. Apparatus: "GPC-101" manufactured by Showa Denko K.K. GPC column: "GPC-KF-801", "GPC-KF-802", "GPC-KF-803", and "GPC-KF-804" manufactured by Shimadzu GLC Corporation combined together Mobile phase: tetrahydrofuran (THF) Column temperature: 40°C Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass Sample injection amount: 100 μL Detector: differential refractometer Standard material: monodisperse polystyrene

[0108] The abbreviations of the compounds used in the following examples are shown below. For convenience, hereinafter, a "compound represented by formula (X)" may be simply referred to as "compound (X)."

[0109] (Silane compounds) S-1 to S-4

[0110] (Carboxylic Acid) C-1 to C-4

[0111] (Monomers having unsaturated bonds) A-1 to A-9

[0112] (Crosslinking Agents) AD-1 to AD-3

[0113] 1. Synthesis of Polyorganosiloxane [Synthesis Example 1-1] 100.0 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (compound (S-1)), 500 g of methyl isobutyl ketone, and 10.0 g of triethylamine were charged into a 1,000 mL three-neck flask and mixed at room temperature. Next, 100 g of deionized water was added dropwise from the dropping funnel over 30 minutes, and the mixture was then mixed under reflux at 80 ° C. for 6 hours. After completion of the reaction, the organic layer was removed and washed with a 0.2% by mass aqueous solution of ammonium nitrate until the water after washing was neutral, and then the solvent and water were distilled off under reduced pressure. An appropriate amount of methyl isobutyl ketone was added to obtain a 50% by mass solution of polymer (ESSQ-1), which is a polyorganosiloxane having epoxy groups. In a 500 mL three-necked flask, 50 mol% of compound (C-1) relative to the amount of epoxy groups in the polymer (ESSQ-1), 1.00 g of tetrabutylammonium bromide, 20.0 g of the polymer (ESSQ-1)-containing solution, and 290.0 g of methyl isobutyl ketone were added and stirred at 90 ° C. for 18 hours. After cooling to room temperature, the separation and washing operation with distilled water was repeated 10 times. Thereafter, the organic layer was collected and concentrated using a rotary evaporator and diluted with cyclopentanone twice, and then the solids concentration was adjusted to 30% by mass using cyclopentanone to obtain a cyclopentanone solution of polyorganosiloxane (referred to as polymer (PS-1)). １ H-NMR measurement, ２９ The structure of the polymer (PS-1) was confirmed by Si-NMR measurement, gel permeation chromatography (GPC), and quadrupole time-of-flight mass spectrometry (QTOF-MS), and it was confirmed to be a polyorganosiloxane mainly composed of a mixed structure of a cage structure and an incomplete cage structure. The weight average molecular weight of the polymer (PS-1) was 2,500.

[0114] [Synthesis Examples 1-2 to 1-9] Polymers (PS-2) to (PS-9) were obtained by the same procedure as in Synthesis Example 1-1, except that the types and amounts of compounds used in the synthesis were changed as shown in Table 1. In Table 1, the amount of siloxane monomer represents the amount (molar parts) of each compound used relative to 100 parts by mass of the total amount of siloxane monomer used in the synthesis of polyorganosiloxane having epoxy groups. The amount of carboxylic acid represents the amount (mol%) of each compound used relative to the total amount of epoxy groups possessed by polyorganosiloxane having epoxy groups.

[0115]

[0116] 2. Synthesis of Polyamic Acid [Synthesis Example 2-1] 100 parts by mole of 2,3,5-tricarboxycyclopentylacetic dianhydride as a tetracarboxylic dianhydride and 100 parts by mole of 3,5-diaminobenzoic acid as a diamine compound were dissolved in N-methyl-2-pyrrolidone (NMP), and the mixture was allowed to react at 60°C for 6 hours to obtain a solution containing 20% ​​by mass of polyamic acid (referred to as polymer (PI-1)).

[0117] 3. Synthesis of Addition Polymer [Synthesis Example 3-1] Under nitrogen, a 100 mL three-neck flask was charged with 21 moles of compound (A-1), 21 moles of compound (A-2), 38 moles of compound (A-3), and 20 moles of compound (A-6), relative to a total of 100 moles of polymerization monomers, 0.0150 g of 2,2'-azobis(2,4-dimethylvaleronitrile) as a radical polymerization initiator (1 part by mass relative to 100 parts by mass of the total amount of polymerization monomers), and 13.49 g of cyclopentanone as a solvent (900 parts by mass relative to 100 parts by mass of the total amount of polymerization monomers), and the mixture was stirred at 60 ° C. for 6 hours, and then stirred at 100 ° C. for 1 hour. The reaction solution was added dropwise to methanol to cause reprecipitation, and the precipitate was filtered and dried in vacuo at room temperature for 8 hours to obtain the desired addition polymer (referred to as polymer (PA-1)).

[0118] Polymers (PA-2) to (PA-5) were obtained in the same manner as in Synthesis Example 3-1, except that the types and amounts of compounds used in the synthesis were changed as shown in Table 2. In Table 2, the amount of monomer represents the amount (parts by mole) of each compound used relative to 100 parts by mass of the total amount of polymerization monomers used in the synthesis of the addition polymer.

[0119]

[0120] 4. Production and Evaluation of Transfer Stamp Material [Example 1] (1) Preparation of Thermosensitive Adhesive Composition 100 parts by mass of polymer (PS-1) and 2 parts by mass of crosslinking agent (AD-1) were diluted with cyclopentanone to adjust the total solid content of the polymer and additives to 25% by mass, thereby obtaining a thermosensitive adhesive composition (ST-1).

[0121] (2) Preparation of transfer stamp material (film-formed film) The heat-sensitive adhesive composition (ST-1) prepared in (1) above was applied to a Kapton (registered trademark) film with a film thickness of 25 μm fixed on a glass substrate using a spin coater, and heated for 1 minute on a hot plate at 80° C. Thereafter, the film was heated for 20 minutes in an oven at 230° C. whose interior was replaced with nitrogen, to obtain a film-formed film with an average film thickness of 1 μm as a thin-film transfer stamp material.

[0122] (3) Element Pickup Evaluation: The transfer stamp material prepared in (2) above was cut into 5 mm squares and attached to a glass slide (1.0 mm thick) via double-sided tape to form a transfer stamp. This transfer stamp was fixed to a precision automated stage. A GaAs thin-film element (15 μm square, 0.1 μm thick) prepared on a GaAs source substrate was used as the transfer target, and the source substrate was fixed on a hot plate. Pickup was performed by setting the hot plate temperature to a predetermined temperature, contacting the transfer stamp with the top surface of the thin-film element, waiting for 5 seconds, and then lifting the stage at 1000 μm / s. During operation, optical observation was performed from above the transfer stamp using an epi-illumination optical microscope, and the transfer stamp and thin-film element were aligned. These operations were repeated while increasing the hot plate temperature from room temperature (20°C) in 10°C increments, and the hot plate temperature at which element pickup was successful was recorded as the successful pickup temperature. Note that pickup failures regardless of temperature were evaluated as unsuccessful and indicated as "x" in Table 3. As a result, Example 1, which used the transfer stamp material made of the temperature-sensitive adhesive composition (ST-1), was successful in picking up at 30°C.

[0123] (4) Element Release Evaluation: The thin-film element picked up by the operation (3) above was brought into contact with a predetermined position on a target substrate (a silicon substrate with a thermal oxide film), and after waiting for 5 seconds, the transfer stamp was lifted to release the element. In the element release series of operations, the target substrate was fixed on a hot plate. The transfer stamp was lifted at a speed (release speed) of 10 μm / s. This operation was repeated, raising the temperature by 10°C from the successful pickup temperature, and the temperature at which the element was successfully released was recorded as the successful release temperature. The released thin-film element and target substrate were observed under a microscope for contamination (presence or absence of adhesive residue). A good (○) was evaluated if no contamination was present, and a poor (×) was evaluated if contamination was observed. Furthermore, a good (○) was evaluated if the element was released to the desired position, and a poor (×) was evaluated if it could not be released to the desired position. If the released thin-film element and target substrate were not contaminated, the release speed was changed to 100 μm / s or 1000 μm / s, and the element release evaluation was performed again, and the release speed at which the release was successful was recorded. When the element release was successful at a release speed of 100 μm / s or more, it was evaluated as best (◎); when the element release was not successful at a release speed of 100 μm / s or more but was successful at a release speed of 10 μm / s, it was evaluated as good (◯); and when the element could not be released at a release speed of 10 μm / s, it was evaluated as poor (×). Separately, the same operation as above was performed with the release speed set to less than 10 μm / s, and when the element was released at a release speed of less than 10 μm / s, it was also evaluated as poor (×). As a result, in Example 1, which used a transfer stamp material prepared from the temperature-sensitive adhesive composition (ST-1), the element was successfully released at a release speed of 1000 μm / s at 70° C. without contamination.

[0124] (5) Evaluation of the temperature difference between the successful pickup temperature and the successful release temperature. The temperature difference between the successful pickup temperature obtained in (3) above and the successful release temperature obtained in (4) above was evaluated. The smaller this temperature difference, the faster the element can be picked up and released, and the better the operability can be evaluated. A temperature difference of 50°C or less was evaluated as good (○), and a temperature difference of 50°C or more was evaluated as bad (×). However, if there was any contamination on the thin-film element or target substrate after release in (4) above, it was deemed unevaluable and is indicated by "-" in Table 3. As a result, Example 1, which used a transfer stamp material prepared from the temperature-sensitive adhesive composition (ST-1), had a temperature difference of 40°C and was evaluated as good (○).

[0125] Examples 2 to 12, Comparative Examples 1 to 6: A thermosensitive adhesive composition and a transfer stamp material (film-formed film) were produced in the same manner as in Example 1, except that the types and amounts of polymer and crosslinker were changed as shown in Table 3. The resulting transfer stamp material (film-formed film) was used to produce a transfer stamp, and element pickup evaluation, element release evaluation, and evaluation of the temperature difference between successful pickup and successful release temperatures were performed. In Comparative Example 1, Dow's SYLGARD® 184 Silicone Elastomer Kit was used. This kit is a two-part mixture, so it was diluted with cyclopentanone so that the total solids concentration of the two materials was 25% by mass, yielding a thermosensitive adhesive composition (ST-13). The evaluation results are shown in Table 3.

[0126]

[0127] As shown in Table 3, in Examples 1 to 12, elements could be picked up even when the operation speed of the transfer stamp during element pickup was set to a sufficiently high speed of 1000 μm / s. Furthermore, during element release, elements could be released even when the transfer stamp was pulled up at a high operation speed of 10 μm / s or more. In particular, in Examples 1 to 4 and 6 to 9, elements could be released even when the transfer stamp was pulled up at an operation speed of 100 μm / s or more, which significantly improved throughput. Furthermore, in Examples 1 to 12, there was no contamination on the substrate or element after element release, and the positional accuracy of the element was also good. Furthermore, the temperature difference between the successful pickup temperature and the successful release temperature was small, and operability was also good.

[0128] In contrast, in Comparative Examples 1 to 3, 5, and 6, although the elements could be picked up, when the release speed was set to 10 μm / s, the elements were pulled up together with the transfer stamp during release, making it impossible to release the elements. Furthermore, in Comparative Examples 2 and 3, contamination of the substrate and elements occurred after the elements were released, and the positional accuracy of the elements was low due to the influence of contaminating components (e.g., components melted from the transfer stamp material) and deformation of the transfer stamp material during heating. Furthermore, in Comparative Examples 5 and 6, the temperature difference between the successful pickup temperature and the successful release temperature was large. In Comparative Example 4, when the operation speed of the transfer stamp was set to 1000 μm / s, it was impossible to pick up the elements.

[0129] 10...micro transfer printing device, 11...transfer stamp, 12...controller, 13...support part, 14...stamp part, 14A...fixing part, 14B...adhesive part, 20...microelement, 21...source substrate, 22...target substrate, 23, 24...temperature controller

Claims

1. A transfer stamp material used in microtransfer printing, which is an alkyl group having 10 or more carbon atoms and a part of the methylene group in the alkyl group having 10 or more carbon atoms is -O-, -S-, -CO-, -COO-, -OCO-, -NR １Ａ --CO-NR １Ａ -, -NR １Ａ —CO—, —NR １Ａ -CO-NR １Ｂ -, -NR １Ａ —CO—O— or —O—CO—NR １Ａ -substituted group (wherein R １Ａ and R １Ｂ and each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms).

2. The transfer stamp material according to claim 1, wherein the polymer (A) further comprises an oxiranyl group, an oxetanyl group, or both.

3. The transfer stamp material according to claim 1, wherein the polymer (A) further has a hydroxy group.

4. The transfer stamp material according to claim 1, wherein the polymer (A) further comprises an oxiranyl group, an oxetanyl group, or both, and a hydroxy group.

5. The transfer stamp material according to claim 1, wherein the polymer (A) is at least one selected from the group consisting of polyorganosiloxanes and addition polymers.

6. The transfer stamp material according to claim 1, wherein the polymer (A) is a polyorganosiloxane having one or both of a cage structure and an incomplete cage structure.

7. The transfer stamp material according to claim 1, wherein the polymer (A) has at least one type of partial structure selected from the group consisting of a partial structure represented by the following formula (1-1) and a partial structure represented by the following formula (1-2) in a side chain. (In formula (1-1) and formula (1-2), X １ and X ２ are each independently —O—, —S—, or —NR ４ -, -CO-, -COO-, -OCO-, -CO-NR ４ -or-NR ４ -CO-. ４ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ２ and R ３ are each independently the specific group. "*" represents a bond.

8. The transfer stamp material according to claim 1, wherein the polymer (A) is a reaction product of a polymer containing a structural unit represented by the following formula (S-1) and a carboxylic acid having the specific group: (In formula (S-1), R ６ is a monovalent group having an oxetanyl group or an oxiranyl group.

9. The transfer stamp material according to claim 1, wherein the polymer (A) is crosslinked.

10. The transfer stamp material according to claim 1, further comprising a polymer (B) having no specific group.

11. The transfer stamp material according to claim 10, wherein the polymer (B) has a carboxy group.

12. The transfer stamp material according to claim 10, wherein the polymer (A) and the polymer (B) have different main chain skeletons.

13. A thermosensitive adhesive composition for forming an adhesive layer whose adhesive strength changes depending on the temperature, comprising an alkyl group having 10 or more carbon atoms and a methylene group in the alkyl group having 10 or more carbon atoms, wherein the alkyl group is -O-, -S-, -CO-, -COO-, -OCO-, or -NR １Ａ --CO-NR １Ａ -, -NR １Ａ —CO—, —NR １Ａ -CO-NR １Ｂ -, -NR １Ａ —CO—O— or —O—CO—NR １Ａ -substituted group (wherein R １Ａ and R １Ｂ and each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms), and a solvent.

14. The heat-sensitive adhesive composition according to claim 13, wherein the polymer (A) is a polyorganosiloxane.

15. The temperature-sensitive adhesive composition according to claim 14, wherein the polyorganosiloxane has one or both of a cage structure and an incomplete cage structure.

16. The heat-sensitive adhesive composition according to claim 13, wherein the polymer (A) further has at least one of an oxiranyl group, an oxetanyl group, or both of them.

17. The heat-sensitive adhesive composition according to claim 13, wherein the polymer (A) further has a hydroxy group.

18. The heat-sensitive adhesive composition according to claim 13, wherein the polymer (A) has at least one type of partial structure selected from the group consisting of a partial structure represented by the following formula (1-1) and a partial structure represented by the following formula (1-2) in a side chain: (In formula (1-1) and formula (1-2), X １ and X ２ are each independently —O—, —S—, or —NR ４ -, -CO-, -COO-, -OCO-, -CO-NR ４ -or-NR ４ -CO-. ４ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ２ and R ３ are each independently the specific group. "*" represents a bond.

19. The heat-sensitive adhesive composition according to claim 13, wherein the polymer (A) is a reaction product of a polymer containing a structural unit represented by the following formula (S-1) and a carboxylic acid having the specific group: (In formula (S-1), R ６ is a monovalent group having an oxetanyl group or an oxiranyl group.

20. The heat-sensitive adhesive composition according to claim 13, further comprising a crosslinking agent.

21. The heat-sensitive adhesive composition according to claim 20, wherein the crosslinking agent has, in one molecule, a total of two or more of at least one type selected from the group consisting of an oxiranyl group, an oxetanyl group, a cyclic carbonate group, a hydroxy group, a protected hydroxy group, a carboxy group, a protected carboxy group, a mercapto group, a protected mercapto group, an amino group, a protected amino group, an isocyanate group, a protected isocyanate group, and a polymerizable carbon-carbon unsaturated bond group.

22. The heat-sensitive adhesive composition according to claim 13, further comprising a polymer (B) having no specific group.

23. The heat-sensitive adhesive composition according to claim 22, wherein the polymer (B) has a carboxy group.

24. The heat-sensitive adhesive composition according to claim 22, wherein the main chain skeletons of the polymer (A) and the polymer (B) are different.

25. A micro-transfer printing device comprising a transfer stamp formed from the transfer stamp material of any one of claims 1 to 12.

26. A transfer printing method for transferring an element on a source substrate from the source substrate to a predetermined position on a target substrate using the microtransfer printing device described in claim 25, comprising the steps of bringing the transfer stamp into contact with the element and picking up the element with the transfer stamp, and releasing the element picked up by the transfer stamp from the transfer stamp and placing it at the predetermined position, wherein the temperature of the element when released is higher than the temperature when picked up, and the temperature of the element when released is 60°C or higher.

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