Underfill material, cured film, and LED display device

Abstract

To provide an underfill material that has photosensitivity, flux functionality, and adhesiveness, and can be patterned to form a film solely on required areas of an array substrate, which enables mass transfer of LED devices and efficient metal bonding.SOLUTION: A thermosetting positive photosensitive adhesive composition contains the following component (A), component (B), component (C) and component (D). Component (A): an alkali-soluble resin that includes a phenolic hydroxy group and has a polymeric glass transition temperature (Tg) of 60°C or lower. Component (B): a crosslinker. Component (C): a photosensitizer with quinonediazide. Component (D): a solvent.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an underfill material for micro LED display elements, an underfill film, a method for manufacturing an underfill film, and a micro LED display element, and in particular to an underfill material used in micro LED display elements, a method for manufacturing an underfill film, an underfill film obtained by the manufacturing method, and a micro LED display element using the underfill film. [Background technology]

[0002] Currently, liquid crystal display elements (LCDs) and organic light-emitting diode display elements (OLEDs) are mainly used for flat panel displays used in mobile phones, monitors, and TVs. LCDs have already been fully mass-produced, and are inexpensive and can be made large. However, they are inferior in form factor and flexibility because they require a backlight for display. OLEDs are also excellent in flexibility, but they have the problem that their lifespan shortens when the brightness of the display element is increased. As a display element that can solve these shortcomings, micro LED display elements have been developed in recent years, which display by arranging inorganic light-emitting diodes on each pixel of an array substrate. Micro LED display elements use micrometer-sized inorganic light-emitting diodes as the light source, so they can achieve higher brightness, higher color purity, and a longer lifespan than LCDs and OLEDs. In addition, because LEDs are arranged for each pixel, each pixel can be made independent, and they are also excellent in flexibility.

[0003] The LED elements that are the light source are supplied as small pieces by epitaxially growing a semiconductor layer on a sapphire substrate, forming electrodes, and then dicing the substrate. Micro LED display elements require LED elements manufactured in this way to be arranged on an array substrate with high precision. Until now, the pick and place method, in which each LED element is installed one by one, has been considered as a method for arranging LED elements on an array substrate. However, this method requires a huge amount of time to install the LEDs, making it unsuitable for mass production.

[0004] In response to this, a stamp method has been proposed in recent years, in which a large number of LED elements are picked up from a sapphire substrate at once using an adhesive base material (stamp), mass-transferred to an array substrate, and then the LED elements are bonded to the electrodes of the array substrate by thermocompression bonding using a bonding head or by metal bonding using laser heating (Non-Patent Documents 1 and 2). Using this method, a large number of LED elements can be arranged on the array substrate at once and bonded to the array substrate, and it is expected to significantly improve throughput compared to the Pick & Place method. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Adv.Optical Mater.2015,3,1313-1335 [Non-Patent Document 2] SID 2017 DIGEST, 257 Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, the mass transfer method using stamps has the potential to significantly improve throughput compared to the pick-and-place method, in which LED elements are arranged one by one on an array substrate. However, this method requires an adhesive film on the array substrate because it is a method of mass-transferring the LED elements from the sapphire substrate to the array substrate, due to the difference in adhesiveness between the array substrate and the LED elements and between the stamp and the LED elements. On the other hand, if a film is formed on the array substrate for mass transfer, there is also the issue that it is difficult to extract the wiring afterwards.

[0007] In addition, when mass-transferred LED elements are metal-bonded to the array substrate by thermocompression or laser heating, if an oxide film is formed on the electrodes of the array substrate or LED elements, metal bonding cannot be achieved and electrical continuity problems occur. For this reason, when joining LED elements, flux treatment to remove the metal oxide film is usually required before bonding.

[0008] Therefore, an object of the present invention is to provide an underfill material that has photosensitivity, flux properties and adhesive properties, and that enables efficient mass transfer and metal bonding of LED elements by forming a film only in necessary locations on an array substrate through patterning.

[0009] Another object of the present invention is to provide an underfill film patterned on an array substrate, which uses the underfill material and enables efficient mass transfer and metal bonding of LED elements.

[0010] It is yet another object of the present invention to provide a method for producing an underfill film using the underfill material, which enables efficient mass transfer and metal bonding of LED elements.

[0011] And, an object of the present invention is to provide a micro LED display element having an underfill film that enables efficient mass transfer and metal bonding of the LED element. [Means for solving the problem]

[0012] The present inventors have conducted intensive research to solve the above problems and have come up with the present invention. 1. A positive photosensitive adhesive composition comprising the following components (A), (B), (C), and (D) a solvent: Component (A): An alkali-soluble resin having a phenolic hydroxyl group and a glass transition temperature (Tg) of 60°C or lower Component (B): Crosslinking agent Component (C): Photosensitizer containing quinone diazide (D) Component: Solvent 2. The positive photosensitive adhesive composition according to 1, wherein the component (A) is a polymer containing a structural unit derived from a monomer (A2) that provides a homopolymer having a Tg of 0° C. or lower. 3. The positive photosensitive adhesive composition according to 2, wherein the component (A) is an acrylic polymer containing, as constituent components, constituent units derived from a monomer (A1) having a phenolic hydroxyl group and a polymerizable unsaturated group, and a monomer (A2) having a homopolymer Tg of 0°C or lower. 4. The positive photosensitive adhesive composition according to 3, wherein the monomer (A1) having a phenolic hydroxyl group and a polymerizable unsaturated group is selected from the group consisting of p-hydroxystyrene, m-hydroxystyrene, α-methyl-p-hydroxystyrene, and compounds represented by the following formula (1): [ka] In formula (1), P represents a (meth)acrylic group, a (meth)acrylamide group, an N-methyl(meth)acrylamide group, or a maleimide group; b1 represents a single bond, or a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, or a combination thereof; c1 represents a single bond, -O-, -COO-, or -OCO-; and d1 represents a substituted or unsubstituted hydroxyphenyl group. 5. The positive photosensitive adhesive composition according to any one of 3 to 4, wherein the monomer (A2) which gives a homopolymer having a Tg of 0° C. or lower is a compound represented by the following formula (2): [ka] In formula (2), R2 represents a hydrogen atom or a methyl group, a2 represents an oxygen atom or a sulfur atom, b2 represents a linear, branched or cyclic alkylene group having 2 to 20 carbon atoms or a combination thereof, and -CH2- in the alkylene group may be replaced with an oxygen atom, provided that they are not adjacent to each other, c2 represents a single bond, -O-, -COO- or -OCO-, and d2 represents a hydrogen atom or a hydroxyl group. 6. The positive photosensitive adhesive composition according to any one of 1 to 5, wherein the component (A) is an acrylic polymer further containing, as a constituent component, a constituent unit derived from a monomer (A3) containing an aromatic hydrocarbon group represented by the following formula (3): [ka] In formula (3), R3 represents a hydrogen atom or a methyl group, a3 represents an oxygen atom, a sulfur atom, -NH-, or -N(CH3)-, b3 represents a single bond, or a linear, branched, or cyclic alkylene group having 1 to 20 carbon atoms, or a combination thereof, in which -CH2- may be replaced with an oxygen atom, provided that they are not adjacent to each other, c3 represents a single bond, -O-, -COO-, -OCO-, -NHCO-, -CONH-, -N(CH3)CO-, or -CON(CH3)-, and d3 represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms. 7. The positive photosensitive adhesive composition according to any one of 1 to 6, wherein the amount of the component (B) is 5 to 60 parts by mass per 100 parts by mass of the component (A). 8. The positive photosensitive adhesive composition according to any one of 1 to 7, wherein the amount of the component (C) is 10 to 100 parts by mass per 100 parts by mass of the component (A). 9. The positive photosensitive adhesive composition according to any one of 1 to 8, further comprising a surfactant as the component (E) in an amount of 0.01 to 1.0 part by mass per 100 parts by mass of the component (A). 10. A cured film obtained by curing the positive photosensitive adhesive composition according to any one of 1 to 9. 11. An LED display element having the cured film according to 10 as an underfill material. Effect of the Invention

[0013] The positive-type photosensitive adhesive composition of the present invention has photosensitivity, flux properties and adhesive properties, and by forming a film only in necessary areas on an array substrate by patterning, it is possible to form an underfill material that enables efficient mass transfer and metal bonding of LED elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The positive-type photosensitive adhesive composition of the present invention is a positive-type photosensitive adhesive composition containing the following components (A), (B), (C), and (D) a solvent. Component (A): An alkali-soluble resin having a phenolic hydroxyl group and a glass transition temperature (Tg) of 60°C or lower Component (B): Crosslinking agent Component (C): Photosensitizer containing quinone diazide (D) Component: Solvent Each component will be described in detail below.

[0015] <Component (A)> The component (A) is an alkali-soluble resin that has a phenolic hydroxyl group and has a glass transition temperature (Tg) of not more than 60° C. The alkali-soluble resin is preferably an acrylic polymer.

[0016] In the present invention, the acrylic polymer refers to a polymer obtained by using a monomer having a polymerizable unsaturated group such as an acrylic acid ester, a methacrylic acid ester, styrene, or maleimide, that is, a polymerizable group containing a carbon-carbon double bond in the structure. The alkali-soluble resin of the component (A) is preferably an alkali-soluble acrylic polymer, and there are no particular limitations on the type of main chain skeleton and side chains of the polymer constituting the acrylic polymer.

[0017] If the weight-average molecular weight of the alkali-soluble resin of component (A) is too small, less than 20,000, the alkali resistance decreases in the alkali development step of lithography, and the desired pattern may not be formed, whereas if the weight-average molecular weight is too large, more than 150,000, residues may remain during development. From the viewpoint of these patterning properties, the weight-average molecular weight of the alkali-soluble resin is preferably in the range of 20,000 to 150,000, and more preferably in the range of 30,000 to 100,000.

[0018] The alkali-soluble resin of component (A) can be synthesized simply by copolymerizing a monomer mixture containing monomer (A1) having a phenolic hydroxyl group and a polymerizable unsaturated group, and monomer (A2) having a homopolymer Tg of 0° C. or less. Here, the homopolymer refers to a polymer of monomer (A2) alone, and is a polymer having a weight average molecular weight of 3000 or more obtained by polymerization reaction at a temperature of 50 to 110° C. in a solvent optionally containing a polymerization initiator, etc., or by polymerization reaction by irradiation with ultraviolet light in the presence of monomer (A2) and a photoradical generator, etc.

[0019] The constituent monomers of component (A) are described in detail below. Monomer (A1) is a monomer having a phenolic hydroxyl group and a polymerizable unsaturated group, and is preferably at least one monomer selected from p-hydroxystyrene, m-hydroxystyrene, α-methyl-p-hydroxystyrene, and a compound represented by the following formula (1). [ka] In formula (1), P represents a (meth)acrylic group, a (meth)acrylamide group, an N-methyl(meth)acrylamide group, or a maleimide group, and is preferably a (meth)acrylic group. b1 represents a single bond, or a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, or a combination thereof, and is preferably a single bond or a linear alkylene group having 1 to 6 carbon atoms. c1 represents a single bond, -O-, -COO-, or -OCO-, and is preferably a single bond or -O-. d1 represents a substituted or unsubstituted hydroxyphenyl group, and is preferably a p-hydroxyphenyl group. Examples of the substituent on the hydroxyphenyl group include a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a fluoroalkenyl group having 2 to 3 carbon atoms, a fluoroalkoxy group having 1 to 3 carbon atoms, an alkyloxycarbonyl group having 2 to 3 carbon atoms, a cyano group, a nitro group, etc. By having such a hydroxyphenyl group, component (A) becomes alkali-soluble and also exhibits fluxing properties.

[0020] Examples of the monomer (A1) include p-hydroxystyrene, α-methyl-p-hydroxystyrene, N-(p-hydroxyphenyl)maleimide, N-(p-hydroxyphenyl)acrylamide, N-(p-hydroxyphenyl)methacrylamide, p-hydroxyphenylacrylate, p-hydroxyphenylmethacrylate, etc., which can be used alone or in combination of two or more. Among them, the monomer selected from p-hydroxyphenylacrylate and p-hydroxyphenylmethacrylate is preferred.

[0021] The monomer (A2) is a monomer that gives a homopolymer having a Tg of 0° C. or lower, and is preferably a compound represented by the following formula (2). [ka] In formula (2), R2 represents a hydrogen atom or a methyl group. a2 represents an oxygen atom or a sulfur atom, preferably an oxygen atom. It represents a linear, branched, or cyclic alkylene group having 2 to 20 carbon atoms, or a combination thereof, preferably a linear, branched, or cyclic alkylene group having 2 to 12 carbon atoms, or a combination thereof, more preferably a linear or branched alkylene group having 2 to 12 carbon atoms. In addition, -CH2- in the alkylene group of b2 may be replaced with an oxygen atom, provided that they are not adjacent to each other. c2 represents a single bond, -O-, -COO-, or -OCO-, preferably a single bond or -O-. d2 represents a hydrogen atom or a hydroxyl group.

[0022] Specific examples of the monomer (A2) include ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, tert-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, n-hexyl methacrylate, n-heptyl acrylate, n-heptyl methacrylate, n-octyl acrylate, n-octyl methacrylate, nonyl acrylate, nonyl methacrylate, isononyl acrylate, isononyl methacrylate, lauryl acrylate, lauryl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl acrylate, 3-hydroxypropyl ... Examples of the acrylates include propyl acrylate, 4-hydroxybutyl acrylate, ethyl carbitol acrylate, glycidyl acrylate, methoxytriethylene glycol acrylate, methoxytriethylene glycol methacrylate, 2-methoxyethyl acrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl acrylate, 2-ethoxyethyl methacrylate, tetrahydrofurfuryl acrylate, 3-methoxybutyl acrylate, 3-methoxybutyl methacrylate, diethylene glycol monoacrylate, and diethylene glycol monomethacrylate, which may be used alone or in combination of two or more, but are not limited to these.

[0023] From the viewpoint of suitably obtaining the effects of the present invention, the constituent units derived from monomer (A1) in component (A) preferably account for 10 to 50 mass% of the total of the constituent units derived from monomer (A1) and the constituent units derived from monomer (A2), and the constituent units derived from monomer (A2) in component (A) preferably account for 50 to 90 mass% of the total of the constituent units derived from monomer (A1) and the constituent units derived from monomer (A2).

[0024] In the present invention, when obtaining the acrylic polymer of the component (A), it is preferable to contain a monomer (A3) containing an aromatic hydrocarbon group represented by the following formula (3). [ka] In formula (3), R3 represents a hydrogen atom or a methyl group. a3 represents an oxygen atom, a sulfur atom, -NH-, or -N(CH3)-, preferably an oxygen atom or -NH-, and more preferably an oxygen atom. b3 represents a single bond, or an alkylene group having 1 to 20 carbon atoms, which may be linear, branched, or cyclic, or a combination thereof, and is preferably an alkylene group having 2 to 12 carbon atoms, which may be linear, branched, or cyclic, or a combination thereof, and is more preferably a linear alkylene group having 2 to 8 carbon atoms. In addition, non-adjacent -CH2- in the alkylene group of b3 may be replaced with an oxygen atom, provided that they are not adjacent to each other. c3 represents a single bond, -O-, -COO-, -OCO-, -NHCO-, -CONH-, -N(CH3)CO-, or -CON(CH3)-, and is preferably a single bond, -O-, -COO-, or -OCO-, and more preferably a single bond or -O-. d3 represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, and is preferably a substituted or unsubstituted phenyl group. Examples of the substituent on the aromatic hydrocarbon group include a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a fluoroalkenyl group having 2 to 3 carbon atoms, a fluoroalkoxy group having 1 to 3 carbon atoms, an alkyloxycarbonyl group having 2 to 3 carbon atoms, a cyano group, and a nitro group. When component (A) contains a structural unit derived from a monomer having an aromatic hydrocarbon group represented by formula (3) as a structural component, the alkali resistance of the unexposed area is improved in the development step after exposure, and the contrast ratio when patterned can be improved.

[0025] Specific examples of monomer (A3) include 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, phenyl acrylate, phenyl methacrylate, 4-methylphenyl acrylate, 4-methylphenyl methacrylate, 3-phenoxypropyl acrylate, 3-phenoxypropyl methacrylate, 4-phenoxybutyl acrylate, 4-phenoxybutyl methacrylate, 6-phenoxyhexyl acrylate, 8-phenoxyoctyl acrylate, 2-phenoxypropyl 2-methyl-2-propenoate, 2-(1-methyl-2-phenoxyethoxy)ethyl 2-methyl-2-propenoate, benzyl acrylate, benzyl methacrylate, 4-ethoxybenzyl methacrylate, naphthyl acrylate, and naphthyl methacrylate, which may be used alone or in combination of two or more, but are not limited thereto. Of these, 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, phenyl acrylate, phenyl methacrylate, 4-methylphenyl acrylate, 3-phenoxypropyl acrylate, 3-phenoxypropyl methacrylate, 4-phenoxybutyl acrylate, 4-phenoxybutyl methacrylate, and benzyl methacrylate are preferred.

[0026] When component (A) contains a structural unit derived from monomer (A3), from the viewpoint of obtaining the effects of the present invention favorably, the total of the structural units derived from monomer (A1) and the structural units derived from monomer (A2) in component (A) is preferably 40 to 100 mass%, more preferably 40 to 80 mass%, and even more preferably 50 to 70 mass%, based on the total of the structural units derived from monomer (A1), the structural units derived from monomer (A2), and the structural units derived from monomer (A3). The structural units derived from monomer (A3) in component (A) is preferably 0 to 60 mass%, more preferably 20 to 60 mass%, and even more preferably 30 to 50 mass%, based on the total of the structural units derived from monomer (A1), the structural units derived from monomer (A2), and the structural units derived from monomer (A3).

[0027] In the present invention, when obtaining the acrylic polymer of the component (A), other monomers copolymerizable with the monomers (A1) to (A3) can be used in combination. Specific examples of the other monomers include acrylic acid ester compounds, methacrylic acid ester compounds, maleimides, acrylamide compounds, acrylonitrile, styrene compounds, and vinyl compounds. Specific examples of the other monomers are listed below, but are not limited thereto.

[0028] Examples of the acrylic acid ester compound include methyl acrylate, cyclohexyl acrylate, isobornyl acrylate, 2-methyl-2-adamantyl acrylate, anthryl acrylate, anthryl methyl acrylate, 2,2,2-trifluoroethyl acrylate, 2-aminoethyl acrylate, 2-propyl-2-adamantyl acrylate, caprolactone 2-(acryloyloxy)ethyl ester, and poly(ethylene glycol) ethyl ether acrylate.

[0029] Examples of the methacrylic acid ester compound include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, anthryl methacrylate, anthryl methyl methacrylate, 2,2,2-trifluoroethyl methacrylate, 2-aminomethyl methacrylate, γ-butyrolactone methacrylate, 2-propyl-2-adamantyl methacrylate, caprolactone 2-(methacryloyloxy)ethyl ester, and poly(ethylene glycol) ethyl ether methacrylate.

[0030] Examples of the acrylamide compound include N-methylacrylamide, N-methylmethacrylamide, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N-methoxymethylacrylamide, N-methoxymethylmethacrylamide, N-butoxymethylacrylamide, and N-butoxymethylmethacrylamide.

[0031] Examples of the vinyl compound include methyl vinyl ether, benzyl vinyl ether, cyclohexyl vinyl ether, vinyl naphthalene, vinyl anthracene, vinyl carbazole, allyl glycidyl ether, 3-ethenyl-7-oxabicyclo[4.1.0]heptane, 1,2-epoxy-5-hexene, and 1,7-octadiene monoepoxide.

[0032] Examples of the styrene compound include styrenes having no hydroxy group, such as styrene, α-methylstyrene, chlorostyrene, and bromostyrene.

[0033] The method for obtaining the alkali-soluble resin used in the present invention is not particularly limited, but for example, it can be obtained by polymerization reaction at a temperature of 50 to 110°C in a solvent in which monomer (A1) and monomer (A2), optionally monomer (A3) and the above other monomers, and optionally a polymerization initiator, etc. are coexistent. At that time, the solvent used is not particularly limited as long as it dissolves the monomers constituting the alkali-soluble resin and the alkali-soluble resin. Specific examples include the solvents described in the (D) solvent described later.

[0034] The alkali-soluble resin (hereinafter, also referred to as the specific copolymer) thus obtained is usually in the state of a solution dissolved in a solvent.

[0035] The solution of the specific copolymer obtained as described above can be reprecipitated by adding diethyl ether or water under stirring, and the resulting precipitate can be filtered and washed, and then dried at room temperature or by heating under normal or reduced pressure to obtain a powder of the specific copolymer. By such an operation, the polymerization initiator and unreacted monomers coexisting with the specific copolymer can be removed, and as a result, a powder of the purified specific copolymer can be obtained. If the specific copolymer cannot be sufficiently purified by a single operation, the obtained powder can be redissolved in a solvent and the above operation can be repeated. In the present invention, the powder of the specific copolymer may be used as it is, or the powder may be redissolved in, for example, the solvent (D) described below and used in the form of a solution. In the present invention, the alkali-soluble resin of the component (A) may be a mixture of multiple types of specific copolymers.

[0036] <(B) component> The (B) component is a crosslinking agent, and more specifically, it is a compound having a structure capable of forming a crosslinked structure by thermal reaction with the (A) component. Specific examples are given below, but are not limited to these. The thermal crosslinking agent is preferably selected from, for example, (B1) a crosslinkable compound represented by formula (4) or formula (5) described below, and (B2) a crosslinking agent having an isocyanurate skeleton. These crosslinking agents can be used alone or in combination of two or more kinds.

[0037] The component (B1) may contain a crosslinkable compound represented by formula (4) or formula (5). [ka] In formula (4), k is an integer of 2 to 10, m is an integer of 0 to 4, and X4 represents an organic group having a valence of k. Multiple m's may be the same or different. [ka] In formula (5), k is an integer of 2 to 10, and X5 represents an organic group having a valence of k.

[0038] The component (B1) is not particularly limited as long as it is a compound having a cycloalkene oxide structure represented by formula (4) or a compound having a glycidyl structure represented by formula (5). Specific examples thereof include the following formulas E-2-1 and E-2-2, and the following commercially available products. [ka] [ka]

[0039] Commercially available products include Epolead GT-401, GT-403, GT-301, GT-302, Celloxide 2021, and Celloxide 3000 (trade names, manufactured by Daicel Corporation), alicyclic epoxy resins Denacol EX-252 (trade name, manufactured by Nagase Chemtex Corporation), CY175, CY177, and CY179 (all trade names, manufactured by CIBA-GEIGY AG), Araldite CY-182, CY-192, and CY-184 (all trade names, manufactured by CIBA-GEIGY AG), Epiclon 200 and 400 (all trade names, manufactured by DIC Corporation), Epicoat (all trade names, manufactured by Yuka Shell Epoxy Co., Ltd.), ED-5661, ED-5662 (all trade names, manufactured by Celanese Coatings Co., Ltd.) Examples of such crosslinkable compounds include Epocalic DE-102 and DE-103 (all manufactured by ENEOS Corporation), jER152, jER871 and jER872 (manufactured by Mitsubishi Chemical Corporation), and OGSOL-CG500 (manufactured by Osaka Gas Chemicals Co., Ltd.). These crosslinkable compounds may be used alone or in combination of two or more kinds.

[0040] Among these, from the viewpoints of process resistance, such as heat resistance, solvent resistance, and long-term baking resistance, and transparency, the compounds having a cyclohexene oxide structure and represented by the above formulas E-2-1 and E-2-2, Epolead GT-401, GT-403, GT-301, GT-302, Celloxide 2021, Celloxide 3000, Epocalic DE-102, and Epocalic DE-103 are preferred.

[0041] When the component (B1) is selected as the crosslinking agent, the content is 10 to 60 parts by mass, preferably 10 to 50 parts by mass, and more preferably 20 to 40 parts by mass, per 100 parts by mass of the component (A).

[0042] The positive photosensitive adhesive composition of the present invention may contain a compound having an isocyanurate skeleton as the component (B2). Examples of the compound having an isocyanurate skeleton and two or more polymerizable unsaturated double bonds include compounds having an isocyanurate skeleton and two or more polymerizable unsaturated double bonds, such as trimethallyl isocyanurate, tris(2-acryloyloxyethyl)isocyanurate, and tris(2-methacryloyloxyethyl)isocyanurate, and compounds having an isocyanurate skeleton and two or more epoxy moieties, such as triglycidyl isocyanurate, TEPIC-FL, and TEPIC-VL (all manufactured by Nissan Chemical Industries, Ltd.). When the compound having an isocyanurate skeleton is contained in the positive photosensitive adhesive composition of the present invention, the adhesiveness of the mass-transferred LED chip is improved, and therefore, there is a possibility that the process failure in the mass transfer process can be reduced.

[0043] These compounds may be used alone or in combination of two or more.

[0044] The content of the component (B2) in the positive photosensitive adhesive composition of the present invention is preferably 5 to 60 parts by mass, and more preferably 10 to 50 parts by mass, per 100 parts by mass of the component (A).

[0045] <(C) component> The component (C) is a photosensitizer having quinone diazide, preferably a photosensitizer having 1,2-naphthoquinone diazide. The quinone diazide compound is a compound having either a hydroxyl group or an amino group, or both a hydroxyl group and an amino group, in which preferably 10 to 100 mol %, particularly preferably 20 to 95 mol %, of these hydroxyl groups or amino groups (when both a hydroxyl group and an amino group are present, the total amount of the groups) is esterified or amidated with quinone diazide sulfonic acid.

[0046] Examples of the compound having a hydroxyl group include phenol, o-cresol, m-cresol, p-cresol, hydroquinone, resorcinol, catechol, methyl gallate, ethyl gallate, 1,3,3-tris(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 4,4'-dihydroxyphenylsulfone, 4,4-hexafluoroisopropylidenediphenol, 1,1,1-tris(4-hydroxyphenyl)ethane, 4,4'-[1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bisphenol, 2,4-dihydroxybenzene, 1,2,3,4-tris(4-hydroxyphenyl)ethane ... Examples of the isopropyl alcohol include phenol compounds such as 2,3,4-trihydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,2',3,4,4'-pentahydroxybenzophenone, and 2,5-bis(2-hydroxy-5-methylbenzyl)benzene, and aliphatic alcohols such as ethanol, 2-propanol, 4-butanol, cyclohexanol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 2-methoxyethanol, 2-butoxyethanol, 2-methoxypropanol, 2-butoxypropanol, ethyl lactate, and butyl lactate.

[0047] Examples of the compound containing an amino group include anilines such as aniline, o-toluidine, m-toluidine, p-toluidine, 4-aminodiphenylmethane, 4-aminodiphenyl, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylmethane, and 4,4'-diaminodiphenyl ether, and aminocyclohexane.

[0048] Furthermore, examples of compounds containing both a hydroxyl group and an amino group include aminophenols such as o-aminophenol, m-aminophenol, p-aminophenol, 4-aminoresorcinol, 2,3-diaminophenol, 2,4-diaminophenol, 4,4'-diamino-4''-hydroxytriphenylmethane, 4-amino-4',4''-dihydroxytriphenylmethane, bis(4-amino-3-carboxy-5-hydroxyphenyl)ether, bis(4-amino-3-carboxy-5-hydroxyphenyl)methane, 2,2-bis(4-amino-3-carboxy-5-hydroxyphenyl)propane, and 2,2-bis(4-amino-3-carboxy-5-hydroxyphenyl)hexafluoropropane; and alkanolamines such as 2-aminoethanol, 3-aminopropanol, and 4-aminocyclohexanol.

[0049] These quinone diazide compounds can be used alone or in combination of two or more kinds.

[0050] The content of the (C) component in the positive photosensitive adhesive composition of the present invention is preferably 10 to 100 parts by mass, more preferably 15 to 50 parts by mass, and even more preferably 20 to 40 parts by mass, relative to 100 parts by mass of the (A) component. If it is less than 10 parts by mass, the difference in dissolution rate between the exposed and unexposed parts of the positive photosensitive adhesive composition in the developer may become small, making patterning by development difficult. If it exceeds 100 parts by mass, the quinone diazide compound may not be sufficiently decomposed by short-term exposure to light, resulting in a decrease in sensitivity, or the (C) component may absorb light, resulting in a decrease in transparency of the cured film.

[0051] <(D) Solvent> The (D) solvent used in the present invention dissolves the (A), (B), and (C) components, and also dissolves the (E) component, which is added as desired, and there are no particular limitations on the type or structure of the solvent, so long as it is a solvent having such dissolving ability.

[0052] Examples of such (D) solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-butanone, 3-methyl-2-pentanone, 2 ... Examples of the alkyl ester include pentanone, 2-heptanone, γ-butyrolactone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone.

[0053] These solvents may be used alone or in combination of two or more. Among these (D) solvents, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, 2-heptanone, propylene glycol propyl ether, propylene glycol propyl ether acetate, ethyl lactate, butyl lactate, etc. are preferred from the viewpoint of good film-forming properties and high safety. These solvents are generally used as solvents for photoresist materials.

[0054] <(E) component> The component (E) is a surfactant. The positive photosensitive adhesive composition of the present invention may further contain a surfactant for the purpose of improving the coating property of the composition, as long as the effect of the present invention is not impaired.

[0055] The surfactant of component (E) is not particularly limited, but examples thereof include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants. As this type of surfactant, for example, commercially available products manufactured by 3M Japan Co., Ltd., DIC Corporation, AGC Seimi Chemical Co., Ltd., etc. can be used. These commercially available products are convenient because they are easily available. Specific examples thereof include Polyfox PF-136A, 151, 156A, 154N, 159, 636, 6320, 656, 6520 (manufactured by Omnova), Megafac R30, R08, R40, R41, R43, F251, F477, F552, F553, F554, F555, F556, F557, F558, F559, F560, F56 1, F562, F563, F565, F567, F570 (DIC Corporation), FC4430, FC4432 (3M Japan Ltd.), Asahiguard AG710, Surflon S-386, S-611, S-651, (AGC Seimi Chemical Co., Ltd.), Futergent FTX-218, DFX-18, 220P, 251, 212M, 215M Fluorosurfactants such as BYK-300, 302, 306, 307, 310, 313, 315, 320, 322, 323, 325, 330, 331, 333, 342, 345, 346, 347, 348, 349, 370, 377, 378, 3455 (manufactured by BYK Japan Co., Ltd.), SH3746, SH3749, SH377 1, SH8400, SH8410, SH8700, SF8428 (manufactured by Dow Corning Toray Silicones Co., Ltd.), KF-351, KF-352, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-618, KF-6011, KF-6015 (manufactured by Shin-Etsu Chemical Co., Ltd.), and other silicone surfactants. The surfactant of component (E) can use either a single type alone or a combination of two or more types.

[0056] When a surfactant is used, its content is usually 0.01 to 1.0 part by mass, and preferably 0.02 to 0.8 part by mass, based on 100 parts by mass of the component (A).

[0057] <Other additives> Furthermore, the positive photosensitive resin composition of the present invention may contain, as necessary, a rheology adjuster, a pigment, a dye, a storage stabilizer, an antifoaming agent, or a dissolution promoter such as a polyhydric phenol or a polyvalent carboxylic acid, as long as the effect of the present invention is not impaired. The positive photosensitive adhesive composition of the present invention may further contain a fluxing agent for the purpose of supporting the fluxing effect of the component (A), as long as the effect of the present invention is not impaired. Examples of the fluxing agent include nitrogen-containing compounds having unshared electron pairs (imidazoles, amines, etc.), carboxylic acids, phenols, alcohols, etc. Specific examples include carboxylic acids such as 8-quinolinol, malonic acid, succinic acid, maleic acid, glutaric acid, suberic acid, adipic acid, and sebacic acid, ethylenediamine, 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, alkylbenzimidazole (Tough Ace F2 series: manufactured by Shikoku Kasei), diphenylguanidine hydrobromide, cyclohexylamine hydrobromide, diethylamine hydrochloride, triethanolamine hydrobromide, and monoethanolamine hydrobromide.

[0058] <Positive-type photosensitive adhesive composition> The positive photosensitive resin composition of the present invention is a composition in which a copolymer obtained by copolymerizing (A) component (A1) to (A2) and, if desired, (A3), a crosslinking agent (B), and a 1,2-quinonediazide compound (C) are dissolved in a solvent (D), and may further contain, if desired, one or more of a surfactant (E) and other additives.

[0059] The proportion of solid content in the positive photosensitive adhesive composition of the present invention is not particularly limited as long as each component is uniformly dissolved in the solvent, but is, for example, 1 to 80 mass %, or, for example, 5 to 60 mass %, or 10 to 50 mass %. Here, the solid content refers to all components of the positive photosensitive adhesive composition excluding the solvent (D).

[0060] The method for preparing the positive-type photosensitive adhesive composition of the present invention is not particularly limited, but examples of the preparation method include a method in which component (A) (alkali-soluble resin) is dissolved in solvent (D), and this solution is mixed with component (B) of a crosslinking agent and component (C) of a 1,2-quinone diazide compound in a predetermined ratio to obtain a homogeneous solution, or a method in which component (E) (surfactant) and other additives are further added and mixed at an appropriate stage of this preparation method, if necessary.

[0061] In preparing the positive-type photosensitive adhesive composition of the present invention, the solution of the copolymer obtained by the polymerization reaction in the (D) solvent can be used as it is, and in this case, when the (B) component, the (C) component, etc. are added to the (A) component solution as described above to prepare a uniform solution, the (D) solvent may be further added for the purpose of adjusting the concentration. In this case, the (D) solvent used in the process of forming the specific copolymer and the (D) solvent used for adjusting the concentration in preparing the positive-type photosensitive adhesive composition may be the same or different.

[0062] The prepared solution of the positive photosensitive adhesive composition is preferably used after being filtered using a filter having a pore size of about 0.2 to 5.0 μm.

[0063] <Coating film and cured film> The positive photosensitive adhesive composition of the present invention can be applied onto a semiconductor substrate (e.g., a silicon / silicon dioxide-coated substrate, a silicon nitride substrate, a substrate coated with a metal such as aluminum, molybdenum, or chromium, a glass substrate, a quartz substrate, an ITO substrate, or the like) by spin coating, flow coating, roll coating, slit coating, spin coating followed by slit coating, inkjet coating, or the like, and then pre-dried on a hot plate or in an oven, or the like, to form a coating film. The coating film is then heat-treated to form a positive photosensitive adhesive film.

[0064] The conditions for this heat treatment are, for example, a heating temperature and a heating time appropriately selected from the ranges of 70 to 160° C. and 0.3 to 60 minutes, respectively. The heating temperature and heating time are preferably 80 to 140° C. and 0.5 to 10 minutes.

[0065] The film thickness of the positive-type photosensitive adhesive film formed from the positive-type photosensitive adhesive composition is, for example, 0.1 to 30 μm, or, for example, 1.0 to 10 μm, or, for example, 2.0 to 8 μm.

[0066] A mask having a predetermined pattern is attached to the coating film obtained above, and the film is irradiated with light such as ultraviolet light and developed with an alkaline developer, whereby the exposed areas are washed out and a sharp pattern is obtained at the end faces.

[0067] Examples of the alkaline developer that can be used include aqueous solutions of alkali metal hydroxides such as potassium carbonate, sodium carbonate, potassium hydroxide, and sodium hydroxide, aqueous solutions of quaternary ammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and choline, and aqueous solutions of amines such as ethanolamine, propylamine, and ethylenediamine. Furthermore, surfactants and the like can be added to these developers.

[0068] Among the above, an aqueous solution of 0.1 to 2.38 mass % tetraethylammonium hydroxide is generally used as a developer for photoresists, and the photosensitive adhesive composition of the present invention can also be developed satisfactorily using this alkaline developer without causing problems such as swelling.

[0069] As the developing method, any of the puddle method, dipping method, and swing immersion method can be used. The developing time is usually 15 to 180 seconds.

[0070] After development, the positive photosensitive adhesive film is washed with running water for, for example, 20 to 120 seconds, and then air-dried with compressed air or compressed nitrogen or by spinning to remove moisture on the substrate and obtain a patterned film.

[0071] Subsequently, the pattern-forming film is post-baked for thermal curing, specifically by heating using a hot plate, oven, or the like, to obtain a film having excellent heat resistance, transparency, flattening properties, low water absorption, chemical resistance, and the like, and having a good pattern.

[0072] The post-bake is generally performed at a heating temperature selected from the range of 140 to 270° C. for 5 to 30 minutes on a hot plate or for 30 to 90 minutes in an oven.

[0073] Thus, by such post-baking, a cured film having a desired good pattern shape can be obtained.

[0074] As described above, the film obtained from the positive photosensitive adhesive composition of the present invention has photosensitivity, flux property and adhesive property, and can be suitably used for applications such as an underfill material that enables efficient mass transfer and metal bonding of LED elements by forming a film only in necessary places on an array substrate by patterning. EXAMPLES

[0075] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The abbreviations of the compounds used and the methods for measuring the respective physical properties are as follows. (monomer) HQMA: p-hydroxyphenyl methacrylate PEA: 2-phenoxyethyl acrylate NOAA: n-Octyl acrylate 2EHA: 2-Ethyl-n-hexyl acrylate BA: n-butyl acrylate AA: Acrylic acid MAA: Methacrylic acid MMA: Methyl methacrylate HEMA: 2-hydroxyethyl methacrylate NHPMA: N-(4-hydroxyphenyl)methacrylamide CHMI: N-cyclohexylmaleimide Among the above monomers, HQMA, PEA, and NHPMA correspond to monomer (A1), NOAA, 2EHA, and BA correspond to monomer (A2), and AA, MAA, MMA, HEMA, and CHMI correspond to other monomers. (Radical polymerization initiator) AIBN: α,α'-azobisisobutyronitrile (Photosensitizer) QD: Ester of 4,4'-[1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bisphenol and 6-diazo-5,6-dihydro-5-oxo-1-naphthalenesulfonic acid (manufactured by Toyo Synthetic Co., Ltd.) (Crosslinkable compound) T1: Epolead GT-401 (butanetetracarboxylic acid tetra(3,4-epoxycyclohexylmethyl) modified ε-caprolactone, manufactured by Daicel Corporation) T2: Epochalic DE-102 (manufactured by ENEOS Corporation) T3: TEPIC-FL (Nissan Chemical Co., Ltd.) (solvent) PGME: Propylene glycol monomethyl ether

[0076] <Molecular weight measurement> The molecular weight of the polymer was measured using a room temperature gel permeation chromatography (GPC) apparatus (GPC-101) (Showa Denko KK) and columns (KD-803, KD-805 in series) (Showa Denko KK) as follows. Column temperature: 50℃ Eluent: N,N-dimethylformamide (additives: lithium bromide monohydrate (LiBr·H2O) 30 mmol / L, phosphoric acid anhydrous crystal (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 mL / L) Flow rate: 1.0ml / min Standard samples for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight: approximately 900,000, 150,000, 100,000, and 30,000) (manufactured by Tosoh Corporation) and polyethylene glycol (molecular weight: approximately 12,000, 4,000, and 1,000) (manufactured by Polymer Laboratory Co., Ltd.).

[0077] <Measurement of glass transition temperature (Tg)> The Tg of the polymer obtained in the synthesis examples was measured under the following conditions using a differential scanning calorimeter (DSC) DSC1 (manufactured by METTLER TOREDO). Heating rate: 10℃ / min Measurement temperature: -50℃~150℃ Number of measurements: 2. Tg was calculated from the results of the second heating.

[0078] <Synthesis of acrylic polymer> (Synthesis Example 1) As monomer components constituting the acrylic polymer, HQMA (6.0 g), PEA (6.0 g), and NOAA (8.0 g) were used, and AIBN (0.2 g) was used as a radical polymerization initiator. These were polymerized in a solvent PGME (16.8 g) at a temperature of 60°C to obtain a solution P1 (acrylic polymer concentration: 30.0 mass%) of an alkali-soluble acrylic polymer component (specific copolymer) with Mn (number average molecular weight): 8,100 and Mw (weight average molecular weight): 50,000. The solution of this specific polymer was reprecipitated in water, and then vacuum dried at 50°C to obtain a viscous resin. The Tg of the obtained acrylic polymer was -1°C.

[0079] (Synthesis Example 2) to (Synthesis Example 6) The polymerization reaction was carried out in the same manner as in Synthesis Example 1, except that the ratio (mass ratio) of the monomer components constituting the acrylic polymer and the radical polymerization initiator used was changed as shown in Table 1, to obtain acrylic polymer solutions P2 to P6 (acrylic polymer concentration: 30.0 mass%) having the molecular weight and Tg shown in Table 1.

[0080] (Synthesis Example 7) NHPMA (4.0 g), HEMA (2.0 g), and CHMI (4.0 g) were used as monomer components constituting the acrylic polymer, and AIBN (0.2 g) was used as a radical polymerization initiator. These were polymerized in a solvent PGME (46.5 g) at a temperature of 90°C to obtain a solution P7 (acrylic polymer concentration: 18.0 mass%) of an alkali-soluble acrylic polymer component (specific copolymer) with Mn (number average molecular weight): 5,600 and Mw (weight average molecular weight): 9,300. The obtained acrylic polymer did not show a clear Tg up to 150°C.

[0081] [Table 1]

[0082] <Preparation of Positive Photosensitive Adhesive Composition> (Example 1-1) To prepare a resin solution, a photosensitizer, a crosslinkable compound, and a solvent were added to the acrylic polymer solution (P1) obtained in Synthesis Example 1 above, and the mixture was stirred at room temperature for 2 hours to prepare a positive photosensitive adhesive composition V1 having the composition shown in Table 2.

[0083] (Examples 1-2 to 1-5) and (Comparative Examples 1-1 to 1-3) The resin solution, photosensitizer, crosslinking compound, and solvent types and amounts were changed as shown in Table 2 and then added, followed by stirring at room temperature for 2 hours to prepare positive-type photosensitive adhesive compositions V2 to V5 and RV1 to RV3 having the compositions shown in Table 2.

[0084] [Table 2]

[0085] (Example 2-1) <Adhesion strength evaluation> The positive photosensitive adhesive composition V1 prepared in Example 1-1 was applied to a 5 cm x 5 cm ITO substrate using a spin coater, and then prebaked on a hot plate at a temperature of 100 ° C for 120 seconds to form a prebaked film with a thickness of 3 μm. Thereafter, using a texture analyzer manufactured by Stable Micro Systems, the peel strength of the coating surface was measured at room temperature (23 ° C) using a probe (diameter: 25 mm, material: polypropylene), compression speed: 1 mm / s, tensile speed: 1 mm / s, compression load: 400 g, and compression holding time: 10 s, and 0.3 g or more was marked as ◯, and less than 0.3 g was marked as ×. The results are shown in Table 3.

[0086] <Patterning evaluation> The positive photosensitive adhesive composition V1 prepared in Example 1-1 was applied to a 5 cm x 5 cm ITO substrate using a spin coater, and then prebaked on a hot plate at a temperature of 100°C for 120 seconds to form a prebaked film with a thickness of 3 μm. 2The substrate was irradiated with ultraviolet light through a mask to produce a pattern in which lines / spaces were arranged at intervals of 30 μm / 30 μm. The substrate was then developed by immersing in a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (hereinafter referred to as TMAH) for 60 seconds, and then washed with running ultrapure water for 30 seconds. The substrate was then post-baked at 230° C. for 30 minutes using an ADVANTEC clean oven to form a cured film. The pattern height of the obtained cured film was evaluated as good (◯) when it was less than ±10% of the pre-baked film thickness of 3 μm, and as poor (×) when it was ±10% or more. In addition, the residue in the cutout pattern was evaluated as excellent (◎) when the residue was less than 30 nm, good (◯) when it was 30 nm or more and less than 60 nm, and poor (×) when it was 60 nm or more. The results are shown in Table 3.

[0087] (Examples 2-2 to 2-5 and Comparative Examples 2-1 to 2-3) The positive photosensitive adhesive compositions V2 to V5 and RV1 to RV3 prepared in Examples 1-2 to 1-5 and Comparative Examples 1-1 to 1-3 were used to evaluate the adhesive strength and patterning property in the same manner as in Example 2-1. The results are shown in Table 3.

[0088] [Table 3]

[0089] As shown in Table 3, all of the positive-type photosensitive adhesive compositions of the examples showed good adhesion and patterning properties. In contrast, the positive-type photosensitive adhesive compositions using acrylic polymers with glass transition temperatures (Tg) of 100°C or higher had insufficient adhesion (Comparative Examples 2-1 and 2-3). In addition, those in which the acidic component in the acrylic polymer was a carboxylic acid had poor alkali resistance and could not obtain a pattern shape (Comparative Examples 2-1 to 2-2).

[0090] (Example 3-1) <Flip chip bonding test> As a mounting sample, a TEG (Test Element Group) chip (5.1 mm x 5.1 mm x 700 μm thick) having 1700 electrodes with an electrode area of ​​20 μm x 20 μm and an electrode height of 5.5 μm (SnAg solder height 2.3 μm, copper post electrode height 3.2 μm) and a TEG substrate (15 mm x 15 mm x 700 μm thick) in which copper electrodes were wired to form a daisy chain with the electrodes of the TEG chip were prepared. The positive photosensitive adhesive composition V1 prepared in Example 1-1 was applied onto the TEG substrate using a spin coater, and then prebaked on a hot plate at a temperature of 100 ° C. for 120 seconds to form a prebaked film with a thickness of 6 μm. Next, using a Panasonic flip chip bonder, the TEG chip was flip chip bonded to the TEG substrate having the pre-baked film at a stage temperature of 60°C, a head temperature of 370°C for 60 seconds, and a head pressure of 150N. Then, post-baking (post-curing) was performed at 230°C for 30 minutes to obtain a bonded body. The bonded body obtained was evaluated for the presence or absence of peeling of the TEG chip (no peeling: ◯, peeling: ×) and the conductive resistance value (less than 100Ω: ◯, 100Ω or more: ×). The results are shown in Table 4.

[0091] (Examples 3-2 to 3-4, Comparative Example 3-1) A flip chip bonding test was carried out in the same manner as in Example 3-1 using the positive photosensitive adhesive compositions V2 to V4 and RV3 prepared in Examples 1-2 to 1-4 and Comparative Example 1-3. The results are shown in Table 4.

[0092] (Comparative Example 3-2) Instead of using a positive photosensitive adhesive composition, the TEG chip and the TEG substrate were washed with a 5% by mass aqueous sulfuric acid solution before flip chip bonding to remove the surface oxide film, and the same procedure was followed to form a bonded body, check whether the TEG chip peeled off, and measure the conductive resistance. The results are shown in Table 4.

[0093] [Table 4]

[0094] As shown in Table 4, in the TEG bonded bodies using the positive photosensitive adhesive compositions of the Examples, the TEG chip did not peel off and the conductive resistance value was good (Examples 3-1 to 3-4). In contrast, in the TEG bonded bodies using the positive photosensitive adhesive compositions of the Comparative Examples, the TEG chip did not peel off but the conductive resistance value was poor, suggesting that the resin composition between the electrodes was not sufficiently expelled during flip chip bonding (Comparative Example 3-1). In addition, when the positive photosensitive adhesive composition was not used, the peeling of the TEG chip significantly increased and the resistance value could not be measured with good reproducibility (Comparative Example 3-2).

Claims

1. An underfill material comprising the following components (A), (B), (C), and (D) a solvent: Component (A): an alkali-soluble resin having a phenolic hydroxyl group and a glass transition temperature (Tg) of 60° C. or lower Component (B): Crosslinking agent Component (C): Photosensitizer containing quinone diazide Component (D): Solvent

2. 2. The underfill material according to claim 1, wherein the component (A) is a polymer containing a structural unit derived from a monomer (A2) that provides a homopolymer having a Tg of 0° C. or lower.

3. 3. The underfill material according to claim 2, wherein the component (A) is an acrylic polymer containing, as constituent components, constituent units derived from a monomer (A1) having a phenolic hydroxyl group and a polymerizable unsaturated group, and a monomer (A2) having a homopolymer Tg of 0°C or lower.

4. 4. The underfill material according to claim 3, wherein the monomer (A1) having a phenolic hydroxyl group and a polymerizable unsaturated group is selected from the group consisting of p-hydroxystyrene, m-hydroxystyrene, α-methyl-p-hydroxystyrene, and a compound represented by the following formula (1): 【Chemistry 1】 In formula (1), P represents a (meth)acrylic group, a (meth)acrylamide group, an N-methyl(meth)acrylamide group, or a maleimide group; b １ represents a single bond, or a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, or a combination thereof; １ represents a single bond, -O-, -COO-, or -OCO-; d １ represents a substituted or unsubstituted hydroxyphenyl group.

5. The underfill material according to claim 3 , wherein the monomer (A2) having a homopolymer Tg of 0° C. or lower is a compound represented by the following formula (2): 【Chemistry 2】 (In formula (2), R ２ represents a hydrogen atom or a methyl group; ２ represents an oxygen atom or a sulfur atom, b ２ represents a linear, branched, or cyclic alkylene group having 2 to 20 carbon atoms, or a combination thereof, and —CH ２ - may be replaced with an oxygen atom, provided that they are not adjacent to each other. ２ represents a single bond, -O-, -COO-, or -OCO-; d ２ represents a hydrogen atom or a hydroxyl group.)

6. 2. The underfill material according to claim 1, wherein the component (A) is an acrylic polymer further comprising, as a constituent component, a constituent unit derived from a monomer (A3) containing an aromatic hydrocarbon group represented by the following formula (3): 【Chemistry 3】 (In formula (3), R ３ represents a hydrogen atom or a methyl group; ３ is an oxygen atom, a sulfur atom, -NH-, or -N(CH ３ )-, b ３ represents a single bond, or a linear, branched, or cyclic alkylene group having 1 to 20 carbon atoms, or a combination thereof, and —CH ２ - may be replaced with an oxygen atom, provided that they are not adjacent to each other. ３ is a single bond, -O-, -COO-, -OCO-, -NHCO-, -CONH-, -N(CH ３ )CO-, or -CON(CH ３ )-, d ３ represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms.

7. 2. The underfill material according to claim 1, wherein the amount of the component (B) is 5 to 60 parts by mass per 100 parts by mass of the component (A).

8. 2. The underfill material according to claim 1, wherein the component (C) is 10 to 100 parts by mass per 100 parts by mass of the component (A).

9. 2. The underfill material according to claim 1, further comprising, as component (E), 0.01 to 1.0 part by mass of a surfactant per 100 parts by mass of component (A).

10. A cured film obtained by curing the underfill material according to any one of claims 1 to 9.

11. An LED display element having the cured film according to claim 10 as an underfill film.

Images