Photosensitive organic insulating material composition, insulating film, gate insulating film, transistor, electronic device, and method for manufacturing transistor

Abstract

An objective of the present invention is to provide a photosensitive organic insulating composition having sufficient absorption, even of i-line radiation, as a photosensitive organic insulating composition that has little influence on device reliability and is capable of forming a gate insulating film for transistors. An objective of the present invention is also to provide a gate insulating film and a transistor.　A photosensitive organic insulating composition according to one embodiment of the present invention contains a chalcone compound and polyvinyl cinnamate.

Description

Photosensitive organic insulating material composition, insulating film, gate insulating film, transistor, electronic device, and method for manufacturing transistor

[0001] The present invention relates to a photosensitive organic insulating material composition, an insulating film, a gate insulating film, a transistor, an electronic device, and a method for producing a transistor.

[0002] Photosensitive materials that can be directly patterned are sometimes used as organic insulating film materials for organic electronics, such as organic thin film transistors (OTFTs). For example, Non-Patent Document 1 discloses an OTFT using polyvinyl cinnamate (also known as poly(vinyl cinnamate), hereinafter sometimes referred to as PVCi) as a gate insulating film, which is a photosensitive resin material. However, when the light used for exposure is i-line (wavelength 365 nm), PVCi has problems such as very low i-line absorption and requires a very large exposure dose for curing when using a monochromatic i-line light source. In light of this background, there has been a need for a photosensitive organic insulating composition that maintains insulating properties comparable to PVCi, has high i-line absorption, and does not require a large exposure dose for curing even when using a monochromatic i-line light source.

[0003] Feng, L. et al. Unencapsulated Air-stable Organic Field Effect Transistor by All Solution Processes for Low Power Vapor Sensing. Sci. Rep. 6, 20671; doi: 10.1038 / srep20671 (2016).

[0004] A first aspect of the present invention is a photosensitive organic insulating material composition containing a chalcone compound and polyvinyl cinnamate. A second aspect of the present invention is an insulating film that is a photocured product of the photosensitive organic insulating material composition of the first aspect. A third aspect of the present invention is a gate insulating film that is a photocured product of the photosensitive organic insulating material composition of the first aspect. A fourth aspect of the present invention is a transistor having the gate insulating film of the third aspect. A fifth aspect of the present invention is an electronic device having the thin film transistor of the fourth aspect. A sixth aspect of the present invention is a method for producing a gate insulating film, comprising the steps of applying the photosensitive organic insulating material composition of the first aspect to a substrate and curing the photosensitive organic insulating material composition by exposure to light to form a gate insulating film. A seventh aspect of the present invention is a method for producing a transistor, comprising the step of forming a gate insulating film by the gate insulating film production method of the sixth aspect.

[0005] 1A and 1B are diagrams showing the cross-sectional shapes of organic thin-film transistors. (a): bottom-gate-top-contact organic thin-film transistor; (b): bottom-gate-bottom-contact organic thin-film transistor; (c): top-gate-top-contact organic thin-film transistor; (d): top-gate-bottom-contact organic thin-film transistor. A schematic cross-sectional view showing the structure of a bottom-gate-bottom-contact organic thin-film transistor of Example 1. A schematic diagram of a Metal-Insulator-Metal structure prepared to examine the electrical properties of the organic insulating film obtained from the composition prepared in Example 1. A diagram showing the remaining film ratio versus exposure dose for the insulating films obtained in Examples 1, 6, and Comparative Example 1. A diagram showing the remaining film ratio versus exposure dose for the insulating films obtained in Examples 1, 6, and Comparative Example 1. An enlarged view of FIG. 4. A diagram showing the leakage current between the upper electrode and lower electrode of the MIM structure shown in FIG. 3 in Examples 1, 6, and Comparative Example 1. A diagram showing a method for fabricating organic thin-film transistors in Examples 1 and 16. A diagram showing a microscope image of an OTFT completed in Example 1. A diagram showing the transfer characteristics and bias stress test results of the fabricated OTFT. V of the fabricated OTFT ＴＨ11 is a diagram showing the results of the shift amount. FIG. 12 is a diagram showing the remaining film ratio versus exposure dose for the insulating film obtained in Example 16. FIG. 13 is a diagram showing the remaining film ratio versus exposure dose for the insulating film obtained in Example 16. FIG. 14 is an enlarged view of FIG. 11. FIG. 15 is a diagram showing the leakage current between the upper electrode and lower electrode of the MIM structure shown in FIG. 3 in Example 16 and Comparative Example 1. FIG. 16 is a diagram showing a microscope image of the OTFT completed in Example 16. FIG. 17 shows the transfer characteristics and bias stress test results of the OTFT fabricated in Example 16. FIG. 18 shows the transfer characteristics and bias stress test results of the OTFT fabricated in Comparative Example 1.

[0006] (Photosensitive Organic Insulating Material Composition) Hereinafter, the photosensitive organic insulating material composition of the present invention will be described in detail using a first embodiment and a second embodiment.

[0007] [First embodiment] A photosensitive organic insulating material composition of a first embodiment contains a chalcone compound and polyvinyl cinnamate (PVCi).

[0008] <Chalcone Compounds> Chalcone compounds are chalcone derivatives such as (unsubstituted) chalcone and substituted chalcone. Examples of substituted chalcones include chalcones having one or more substituents selected from the group consisting of alkyl groups having 1 to 5 carbon atoms, alkoxy groups having 1 to 5 carbon atoms, polyoxyalkyl groups having 1 to 5 carbon atoms, alkylamino groups having 1 to 5 carbon atoms, thioalkyl groups having 1 to 5 carbon atoms, sulfonyl groups having 1 to 5 carbon atoms, nitro groups, and cyano groups. Among these, chalcones having one or more substituents selected from the group consisting of alkyl groups having 1 to 5 carbon atoms, alkoxy groups having 1 to 5 carbon atoms, and polyoxyalkyl groups having 1 to 5 carbon atoms are preferred. The number of substituents is preferably 1 to 3, and more preferably 1. The substitution position is preferably on the benzene ring on the alkene side of the unsaturated carbonyl, and more preferably at the ortho or para position. From the viewpoint of facilitating the photodimerization reaction and increasing i-line absorption, chalcones in which an alkoxy group having 1 to 5 carbon atoms is substituted at the para-position of the benzene ring on the alkene side of the unsaturated carbonyl are preferred, with an alkoxy group having 1 to 3 carbon atoms being more preferred. Specific examples of chalcone compounds include chalcone and methoxychalcone. Chalcone, 2-methoxychalcone, and 4-methoxychalcone are more preferred. 4-Methoxychalcone (hereinafter sometimes simply referred to as methoxychalcone) is even more preferred. The chalcone compounds according to this embodiment may be used singly or in combination of two or more.

[0009] <Polyvinyl cinnamate (PVCi)> Polyvinyl cinnamate, also known as poly(vinyl cinnamate), is available from, for example, Sigma-Aldrich Japan LLC.

[0010] <Solvent> The photosensitive organic insulating material composition of this embodiment may further contain a solvent. Examples of the solvent include alcohol-based solvents, ester-based solvents, hydrocarbon-based aromatic solvents, amide-based solvents, ketone-based solvents, glycol ether-based solvents, and ether-based solvents. From the viewpoints of solubility and film-forming properties, the solvent contained is preferably an ester-based or ketone-based solvent, and among these, propylene glycol 1-monomethyl ether 2-acetate (PGMEA) and cyclopentanone are preferred.

[0011] <Other Components> Known antioxidants, light stabilizers, and ultraviolet absorbers may be added to improve weather resistance and light resistance. Known adhesion promoters may be added to improve adhesion. Known surface modifiers may be added to improve leveling properties, surface wettability, or hydrophobicity.

[0012] <Composition Ratio of Composition> The photosensitive organic insulating material composition of this embodiment may contain the chalcone compound and polyvinyl cinnamate in the following mass ratio. The ratio of the total mass of the chalcone compounds to the mass of the polyvinyl cinnamate is 0.01 to 1, preferably 0.01 to 0.3, more preferably 0.03 to 0.3, and even more preferably 0.05 to 0.1. In the photosensitive organic insulating material composition of this embodiment, the total amount of the chalcone compound and polyvinyl cinnamate is preferably 10% by mass to 30% by mass, and more preferably 10% by mass to 15% by mass, relative to 100% by mass of the total composition. In the photosensitive organic insulating material composition of this embodiment, the total amount of the chalcone compounds is preferably 0.1% by mass to 15% by mass, and more preferably 0.1% by mass to 3% by mass, relative to 100% by mass of the total composition.

[0013] <i-Line Sensitivity of Composition> The photosensitive organic insulating material composition of this embodiment preferably has a peak absorption spectrum in the wavelength range of 300 to 370 nm, more preferably in the wavelength range of 320 to 370 nm, even more preferably in the wavelength range of 340 to 370 nm, and most preferably at i-line (365 nm). The photosensitive organic insulating material composition of this embodiment contains a chalcone compound in addition to polyvinyl cinnamate, and therefore exhibits greater i-line absorption than a composition containing only polyvinyl cinnamate. As a result, the time required for photocuring is shortened when using an i-line exposure machine with the same light intensity. This significantly improves productivity. The i-line absorption intensity of the photosensitive organic insulating material composition of this embodiment can be adjusted by the type of chalcone compound, the content of the chalcone compound, etc. For example, when the chalcone compound is an unsubstituted chalcone, it is preferably present in an amount of 10 to 50% by mass relative to 100% by mass of the components (solid content) excluding the solvent of the photosensitive organic insulating material composition, and when the chalcone compound is a methoxychalcone, it is preferably present in an amount of 5 to 25% by mass.

[0014] Second Embodiment A photosensitive organic insulating material composition of a second embodiment contains a polymer having a chalcone skeleton.

[0015] <Polymer Having a Chalcone Skeleton> The chalcone skeleton contained in the polymer according to this embodiment is a structure derived from the various chalcone compounds contained in the photosensitive organic insulating material composition according to the first embodiment. The chalcone compounds according to this embodiment have the same meaning as the chalcone compounds according to the first embodiment, and preferred examples thereof are also the same. The chalcone skeleton contained in the polymer according to this embodiment is preferably a structure contained in a side chain linked to the main chain of the polymer. The main chain of the polymer according to this embodiment is preferably a vinyl polymer chain produced by the polymerization reaction of a monomer having an ethylenically unsaturated bond. The polymer having a chalcone skeleton according to this embodiment preferably has a vinyl polymer main chain and a side chain containing a chalcone skeleton.

[0016] The polymer having a chalcone skeleton according to this embodiment includes a vinyl polymer main chain and a side chain containing a chalcone skeleton, and may also include a side chain that does not contain a chalcone skeleton. The polymer having a chalcone skeleton according to this embodiment preferably includes a vinyl polymer main chain and a side chain containing a chalcone skeleton, and does not include any other side chains.

[0017] The polymer having a chalcone skeleton according to this embodiment is preferably a polymer or copolymer of a monomer containing a substituted chalcone compound having an ethylenically unsaturated group. The substituted chalcone compound having an ethylenically unsaturated group is preferably at least one selected from the group consisting of chalcones having an ethylenically unsaturated group and chalcones having an ethylenically unsaturated group and a methoxy group. Specific examples of the polymer having a chalcone skeleton according to this embodiment include polymers represented by the following formulas (1) to (3).

[0018] (In formula (1), n1 is an integer of 1 to 1000.)

[0019] (In formula (2), n2 is an integer of 1 to 1000.)

[0020] (In formula (3), n3 is an integer of 1 to 1000.)

[0021] The weight-average molecular weight of the polymer having a chalcone skeleton according to this embodiment is preferably 5,000 to 100,000, more preferably 10,000 to 80,000, and even more preferably 20,000 to 50,000. The weight-average molecular weight can be measured by gel permeation chromatography (GPC).

[0022] In the polymer having a chalcone skeleton according to this embodiment, the content of the chalcone skeleton (a structure derived from a chalcone compound, for example, the structure of Compound 3 in the following scheme excluding the —OH group) is preferably 20% by mass to 97% by mass, and more preferably 50% by mass to 80% by mass, relative to 100% by mass of the polymer.

[0023] <Method for producing a polymer having a chalcone skeleton> The method for producing a polymer having a chalcone skeleton according to this embodiment will be described in detail below using the polymer of formula (2) as an example. The method for producing a polymer according to this embodiment includes a step of synthesizing an ethylenically unsaturated compound having a chalcone skeleton and a polymerization step of polymerizing the ethylenically unsaturated compound to form a vinyl polymer main chain.

[0024] The above-mentioned ethylenically unsaturated compound having a chalcone skeleton can be produced by a known method of reacting a compound having a hydroxy group and a chalcone skeleton with an acid chloride having an ethylenically unsaturated group in a solvent. For example, as shown in Scheme 1 below, compound 3 is synthesized by the method described in Non-Patent Document 2. Compound 5 can be synthesized by reacting the obtained phenol derivative compound 3 (or 4'-hydroxy-4-methoxychalcone manufactured by Biosynth) with compound 4.

[0025]

[0026] (Non-patent document 2: X. Yang et. al. with greater cytotoxic effects in leukemia cells, Bioorganic & Medicinal Chemistry Letters, Volume 19, Issue 15, (2009), Pages 4385-4388.

[0027] In the polymerization step of polymerizing an ethylenically unsaturated compound, for example, when the ethylenically unsaturated compound is radically copolymerized, the radical copolymerization can be performed using known methods such as solution polymerization, emulsion polymerization, suspension polymerization, bulk polymerization, etc. The solvent used in the solution polymerization is not particularly limited as long as it dissolves the above-mentioned monomers and the polymer of the present invention, and examples thereof include toluene, xylene, diethyl ether, tetrahydrofuran, 1,4-dioxane, dimethylformamide, dimethyl sulfoxide, etc., and these solvents can also be used in combination.

[0028] The polymerization temperature is selected depending on the initiator used, but is not particularly limited. The initiator is not particularly limited, and examples include azo-based initiators such as azoisobutyronitrile; and peroxide-based initiators such as benzoyl peroxide and di(t-butyl) peroxide. A specific example is 2,2'-azobis(isobutyronitrile) (AIBN). The reaction time is not particularly limited and is set according to the half-life of the initiator used, but is preferably 4 to 30 hours from an economical standpoint.

[0029] For example, as shown in Scheme 2 below, the compound 5 obtained above is polymerized to synthesize compound 6. The synthesis reaction conditions will be described in detail in the Examples. The evaluation results of compound 6 will also be described in the Examples.

[0030]

[0031] In the polymerization step, the ethylenically unsaturated monomers used as raw materials for the polymerization reaction may contain an ethylenically unsaturated compound not having a chalcone skeleton, in addition to an ethylenically unsaturated compound having a chalcone skeleton, such as Compound 5 in Scheme 2. When an ethylenically unsaturated compound not having a chalcone skeleton is contained, the side chains of the resulting polymer will contain side chains not having a chalcone skeleton in addition to side chains having a chalcone skeleton. In this case, the total mass of the ethylenically unsaturated compounds not having a chalcone skeleton is preferably 0 to 50 parts by mass, more preferably 0 to 30 parts by mass, and even more preferably 0 part by mass, relative to 100 parts by mass of the total mass of the ethylenically unsaturated compounds having a chalcone skeleton.

[0032] <Solvent> The photosensitive organic insulating material composition of this embodiment may further contain a solvent. Examples of the solvent include alcohol-based, ester-based, and ketone-based solvents. Among these, propylene glycol 1-monomethyl ether 2-acetate (PGMEA) and cyclopentanone are preferred. Furthermore, the solvent used in the polymerization reaction may be used as is as part of the solvent for the composition.

[0033] <Other Components> Known antioxidants, light stabilizers, and ultraviolet absorbers may be added to improve weather resistance and light resistance. Known adhesion promoters may be added to improve adhesion. Known surface modifiers may be added to improve leveling properties, surface wettability, or hydrophobicity.

[0034] <Composition Ratio of Composition> The polymer having a chalcone skeleton is preferably 50% by mass to 100% by mass, more preferably 75% by mass to 100% by mass, and even more preferably 100% by mass, of 100% by mass of the components (solid content) excluding the solvent of the photosensitive organic insulating material composition of this embodiment. The chalcone compound and polyvinyl cinnamate may be contained in the following mass ratios. In the photosensitive organic insulating material composition of this embodiment, the total amount of the polymer having a chalcone skeleton is preferably 10% by mass to 30% by mass, and more preferably 10% by mass to 15% by mass, relative to 100% by mass of the total amount of the composition.

[0035] <i-Line Sensitivity of Composition> The photosensitive organic insulating material composition of this embodiment preferably has a peak absorption spectrum in the wavelength range of 300 to 370 nm, more preferably in the wavelength range of 320 to 370 nm, even more preferably in the wavelength range of 340 to 370 nm, and most preferably at i-line (365 nm). Because the photosensitive organic insulating material composition of this embodiment contains a polymer having a chalcone skeleton, it exhibits greater i-line absorption than conventional compositions containing only polyvinyl cinnamate. As a result, the time required for photocuring is reduced when using an i-line exposure machine with the same light intensity. This significantly improves productivity. The i-line absorption intensity of the photosensitive organic insulating material composition of this embodiment can be adjusted by the type of chalcone compound relative to the chalcone skeleton, the content of the chalcone skeleton in the polymer, and other factors. For example, when the chalcone compound is methoxychalcone, i.e., when a polymer having a methoxychalcone skeleton is used, the content is preferably 50 to 90 parts by mass. If the i-line absorption is large, the deep curing property will be reduced, resulting in a decrease in photocuring in a thick film and in edge patternability. The content can be adjusted as desired to obtain excellent photocuring property at a desired film thickness.

[0036] (Organic insulating film) An organic insulating film according to one embodiment of the present invention (hereinafter referred to as the organic insulating film according to this embodiment) is obtained by forming a film of one or more types selected from the group consisting of the photosensitive organic insulating material compositions according to the first and second embodiments described above (hereinafter sometimes referred to as the composition according to this embodiment) on a substrate and photocuring the film (photocured product). The composition according to this embodiment can be printed on various substrates. The organic solvent used can be any solvent that dissolves the compounds contained in the composition and, at the same time, does not dissolve materials such as organic semiconductors used in the production of devices such as organic thin-film transistors. Examples of the organic solvent include aromatic hydrocarbon solvents such as cyclohexane, benzene, toluene, xylene, ethylbenzene, isopropylbenzene, N-hexylbenzene, tetralin, decalin, isopropylbenzene, and chlorobenzene; chlorinated aliphatic hydrocarbon compounds such as methylene chloride and 1,1,2-trichloroethylene; aliphatic cyclic ether compounds such as tetrahydrofuran, tetrahydropyran, and dioxane; ketone compounds such as methyl ethyl ketone, cyclopentanone, and cyclohexanone; ester compounds such as ethyl acetate, dimethyl phthalate, methyl salicylate, amyl acetate, and propylene glycol 1-monomethyl ether 2-acetate (PGMEA); alcohols such as n-butanol, ethanol, and isobutanol; and 1-nitropropane, carbon disulfide, and limonene. These solvents can be used in combination as needed. The organic solvent is preferably the same as the organic solvent for synthesis described above, and more preferably propylene glycol 1-monomethyl ether 2-acetate (PGMEA), cyclopentanone, or the like.

[0037] The coating or printing method is not particularly limited, and printing can be performed using, for example, spin coating, drop casting, dip coating, doctor blade coating, pad printing, squeegee coating, roll coating, rod bar coating, air knife coating, wire bar coating, flow coating, gravure printing, flexographic printing, screen printing, inkjet printing, letterpress reverse printing, etc.

[0038] The composition according to this embodiment has a photocrosslinking group having photodimerization reactivity, and radiation is preferably used for the photocrosslinking. Examples of the radiation include ultraviolet and visible light having a wavelength of 245 to 450 nm. From the viewpoint of maximizing the effects of the present invention, radiation near i-line is preferred, and i-line monochromatic light sources are more preferred. The radiation dose can be appropriately changed depending on the composition of the polymer, but is preferably 100 to 300 mJ / cm. ２ In order to prevent a decrease in the degree of crosslinking and improve economic efficiency by shortening the process time, the dose is preferably 50 to 200 mJ / cm ２ The environment for irradiating ultraviolet and visible light is not particularly limited, and irradiation can be performed in the atmosphere, in an inert gas, or under a constant flow of inert gas. If necessary, a photosensitizer can be added to the composition to promote the photocrosslinking reaction. There are no limitations on the photosensitizer used, and examples include benzophenone compounds, anthraquinone compounds, thioxanthone compounds, and nitrophenyl compounds. Two or more types of sensitizers can be used in combination as needed. Furthermore, from the viewpoint of improving the electrical properties of the organic insulating film of this embodiment, it is preferable that the composition is substantially free of photosensitizers. Here, a photosensitizer is a substance that absorbs light and transfers the energy it gains to another substance, thereby assisting the photocrosslinking reaction process. Examples include benzophenone compounds, anthraquinone compounds, thioxanthone compounds, and nitrophenyl compounds. The chalcone compounds contained in the photosensitive organic insulating material composition of the first embodiment described above are not photosensitizers because they absorb light and participate in the photocrosslinking reaction. The term "substantially free" means that the content is so small that no photosensitizing effect is observed. For example, in the composition according to the present embodiment, the content is preferably in the range of 0% by mass to 0.05% by mass, more preferably in the range of 0% by mass to 0.01% by mass, even more preferably in the range of 0% by mass to 0.05% by mass, and even more preferably 0% by mass.

[0039] Furthermore, the photosensitive organic insulating material composition used in the organic insulating film of this embodiment can be photocrosslinked efficiently in a short time. In order to achieve photocrosslinking efficiently in a shorter time, for example, when i-rays are used, it is preferable to set the light irradiation time to 2 minutes or less. Note that, since this is suitable for controlling the crosslinking time, it is even more preferable to set the light irradiation time to 1 minute or less when i-rays are used.

[0040] The organic insulating film of this embodiment can be suitably used as an insulating film for various devices such as an organic thin film transistor, etc. The organic insulating film of this embodiment can be suitably used particularly as a gate insulating film for an organic thin film transistor described below.

[0041] (organic thin film transistor)

[0042] The organic thin-film transistor of this embodiment may have any of the device structures shown in FIG. 1 : bottom gate-top contact type (A), bottom gate-bottom contact type (B), top gate-top contact type (C), and top gate-bottom contact type (D). The polymer of this embodiment is particularly highly applicable to devices of type (A) and (B). In the examples, devices of type (B) were used. Here, 1 represents an organic semiconductor layer, 2 a substrate, 3 a gate electrode, 4 a gate insulating layer, 5 a source electrode, and 6 a drain electrode.

[0043] In the organic thin film transistor, the base material (substrate) that can be used is not particularly limited as long as it can ensure sufficient flatness for fabricating an element, and examples thereof include inorganic material substrates such as glass, quartz, aluminum oxide, highly doped silicon, silicon oxide, tantalum dioxide, tantalum pentoxide, indium tin oxide, etc.; plastics; metals such as gold, copper, chromium, titanium, and aluminum; ceramics; coated paper; surface-coated nonwoven fabric, etc., and may also be composite materials made of these materials or materials in which these materials are multilayered. Furthermore, the surface of these materials can also be coated to adjust the surface tension.

[0044] Examples of plastics that can be used as the substrate include polyethylene terephthalate, polyethylene naphthalate, triacetyl cellulose, polycarbonate, polymethyl acrylate, polymethyl methacrylate, polyvinyl chloride, polyethylene, ethylene-vinyl acetate copolymer, polymethylpentene-1, polypropylene, cyclic polyolefins, fluorinated cyclic polyolefins, polystyrene, polyimide, polyvinylphenol, polyvinyl alcohol, poly(diisopropyl fumarate), poly(diethyl fumarate), poly(diisopropyl maleate), polyethersulfone, polyphenylene sulfide, polyphenylene ether, polyester elastomers, polyurethane elastomers, polyolefin elastomers, polyamide elastomers, styrene block copolymers, etc. Furthermore, two or more of the above plastics can be laminated and used as the substrate.

[0045] Examples of conductive materials that can be used for the gate electrode, source electrode, or drain electrode in this embodiment include gold, silver, aluminum, copper, titanium, platinum, chromium, polysilicon, silicide, indium tin oxide (ITO), tin oxide, etc. Furthermore, a plurality of these conductive materials can be stacked and used.

[0046] In bottom-gate-top-contact (A) elements and bottom-gate-bottom-contact (B) elements, an electrode is formed on the organic semiconductor layer or on the gate insulating film. In this case, the method for forming the electrode is not particularly limited, and examples thereof include vapor deposition, high-frequency sputtering, and electron beam sputtering. Alternatively, methods such as solution spin coating, drop casting, dip coating, doctor blade coating, die coating, pad printing, roll coating, gravure printing, flexographic printing, screen printing, inkjet printing, and letterpress reverse printing can also be employed using an ink in which nanoparticles of the conductive material are dissolved in water or an organic solvent. Furthermore, if necessary, a treatment for adsorbing a fluoroalkylthiol, a fluoroallylthiol, or the like onto the electrode may be performed.

[0047] There are no limitations on the organic semiconductors that can be used in the organic thin-film transistor of this embodiment; either N-type or P-type organic semiconductors can be used, and a bipolar transistor combining N-type and P-type organic semiconductors can also be used. Examples of suitable organic semiconductors include polypyrroles, polythiophenes, polyanilines, polyallylamines, fluorenes, polycarbazoles, polyindoles, and poly(p-phenylene vinylenes). Also suitable organic solvent-soluble low-molecular-weight substances include polycyclic aromatic derivatives such as pentacene, phthalocyanine derivatives, perylene derivatives, tetrathiafulvalene derivatives, tetracyanoquinodimethane derivatives, fullerenes, and carbon nanotubes. Specific examples include condensates of 9,9-di-n-octylfluorene-2,7-di(ethylene boronate) and 5,5'-dibromo-2,2'-bithiophene.

[0048] In this embodiment, a method of dissolving an organic semiconductor in an organic solvent and applying or printing the solution is preferably used as a method for forming the organic semiconductor layer, but there are no limitations as long as a thin film of the organic semiconductor layer can be formed. The concentration of the solution when printing the solution in which the organic semiconductor layer is dissolved in an organic solvent varies depending on the structure of the organic semiconductor and the solvent used, but from the viewpoint of forming a more uniform semiconductor layer and reducing the layer thickness, it is preferably 0.5 to 5 wt %. The organic solvent used in this case is not limited as long as it dissolves the organic semiconductor at a certain concentration that allows film formation, and examples thereof include hexane, heptane, octane, decane, dodecane, tetradecane, decalin, indane, 1-methylnaphthalene, 2-ethylnaphthalene, 1,4-dimethylnaphthalene, a dimethylnaphthalene isomer mixture, toluene, xylene, ethylbenzene, 1,2,4-trimethylbenzene, mesitylene, isopropylbenzene, pentylbenzene, hexylbenzene, tetralin, octylbenzene, cyclohexylbenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, trichlorobenzene, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, γ-butyrolactone, 1,3-butylene glycol, ethylene glycol, benzyl alcohol, glycerin, cyclohexanol acetate, 3-methoxybutyl acetate, ethylene glycol, dipropylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, anisole, cyclohexanone, mesitylene, 3-methoxybutyl acetate, cyclohexanol acetate, dipropylene glycol diacetate, dipropylene glycol methyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, 1,6-hexanediol diacetate, 1,3-butylene glycol diacetate, 1,4-butanediol diacetate, ethyl acetate, phenyl acetate, dipropylene glycol dimethyl ether, dipropylene glycol methyl-N-propyl ether, tetradecahydrophenanthrene, 1,2,3,4,5,6,7,8-octahydrophenanthrene, decahydro-2-naphthol, 1,2,3,4-tetrahydro-1-naphthol, α-terpineol, isophorone triacetin decahydro-2-naphthol, dipropylene glycol dimethyl ether, 2,6-dimethylanisole, 1,2-dimethylanisole, 2,3-dimethylanisole, 3,4-dimethylanisole, 1-benzothiophene, 3-methylbenzothiophene, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, chloroform, dichloromethane, tetrahydrofuran, 1,2-dimethoxyethane, dioxane, cyclohexanone, acetonitrile Examples of suitable solvents include ethanol, methyl ethyl ketone, diethyl ketone, diisopropyl ketone, acetophenone, N,N-dimethylformamide, N-methyl-2-pyrrolidone, and limonene. However, to obtain a crystal film with desirable properties, a solvent with a high dissolving power for organic semiconductors and a boiling point of 100°C or higher is suitable, and xylene, isopropylbenzene, anisole, cyclohexanone, mesitylene, 1,2-dichlorobenzene, 3,4-dimethylanisole, pentylbenzene, tetralin, cyclohexylbenzene, and decahydro-2-naphthol are preferred. Mixed solvents prepared by mixing two or more of the above-mentioned solvents in appropriate ratios can also be used.

[0049] Various organic and inorganic polymers or oligomers, or organic and inorganic nanoparticles, can be added to the organic semiconductor layer as needed, either as a solid or as a dispersion of nanoparticles in water or an organic solvent, and a protective film can be formed by coating the polymer solution on the polymer dielectric layer. Furthermore, various moisture-proof coatings, light-resistant coatings, etc. can be applied to this protective film as needed.

[0050] Examples of the gate electrode, source electrode, or drain electrode that can be used in the organic thin-film transistor of this embodiment include inorganic electrodes such as aluminum, gold, silver, copper, highly doped silicon, polysilicon, silicide, tin oxide, indium oxide, indium tin oxide, chromium, platinum, titanium, tantalum, graphene, and carbon nanotubes, and organic electrodes such as doped conductive polymers (e.g., PEDOT-PSS). A plurality of these conductive materials can also be stacked and used. Furthermore, in order to increase the carrier injection efficiency, these electrodes can be surface-treated using a surface treatment agent. Examples of such surface treatment agents include benzenethiol and pentafluorobenzenethiol.

[0051] Furthermore, there are no particular limitations on the method for forming an electrode on the substrate, insulating layer, or organic semiconductor layer, and examples thereof include vapor deposition, high-frequency sputtering, and electron beam sputtering. It is also possible to employ methods such as solution spin coating, drop casting, dip coating, doctor blade coating, die coating, pad printing, roll coating, gravure printing, flexographic printing, screen printing, inkjet printing, and letterpress reverse printing using an ink in which nanoparticles of the conductive material are dissolved in water or an organic solvent.

[0052] The organic thin-film transistor of this embodiment can be, for example, a bottom-gate-bottom-contact type element used in the examples. Figure 2 is a schematic cross-sectional view showing the structure of a bottom-gate-bottom-contact type organic thin-film transistor, which is an example of this embodiment. This organic thin-film transistor includes a substrate 2, a gate electrode 3 formed on the substrate 2, a gate insulating layer 4 formed on the gate electrode 3, a source electrode 5 and a drain electrode 6 formed on the gate insulating layer 4 with a channel portion sandwiched therebetween, and an organic semiconductor layer 1 formed on the electrodes.

[0053] From the viewpoint of practicality of the organic thin film transistor element, the organic thin film transistor of this embodiment has a mobility of 0.20 cm ２ It is preferable that the voltage Vs is equal to or higher than / Vs.

[0054] In the organic thin film transistor of this embodiment, the threshold voltage is preferably −10.0 V or more and less than 0 V, from the viewpoint of practicality of the organic thin film transistor element.

[0055] From the viewpoint of practicality of the organic thin film transistor element, the organic thin film transistor of this embodiment has a leakage current density of 10 －９ A / cm ２ It is preferable that:

[0056] (Electronic Device Including Organic Thin Film Transistor) The electronic device of this embodiment includes the organic thin film transistor of this embodiment. Examples of the electronic device of this embodiment include an organic electroluminescence element, an organic photoelectric conversion element, and a display.

[0057] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0058] The raw materials, apparatus, etc. used in the examples of the present invention will be described below.

[0059] (Raw Materials) Chalcone: Tokyo Chemical Industry Co., Ltd., product code C0071, purity (test method): >98.0% (GC) Methoxychalcone: Tokyo Chemical Industry Co., Ltd., product code M1409, purity (test method): >98.0% (GC) Polyvinyl cinnamate (PVCi): Sigma-Aldrich, product code 182648 Cyclopentanone: Fujifilm Wako Pure Chemical Industries, Ltd., product code 039-09716, purity (test method): >95.0% (GC) PGMEA: Tokyo Chemical Industry Co., Ltd., product code P1171, purity (test method): >98.0% (GC) Silicon wafer: Shonan Electronic Materials Research Institute, P-type resistivity 1 Ωcm or less Glass substrate: Shonan Electronic Materials Research Institute, soda lime Organic semiconductor layer raw material: 2-decyl-7-phenyl[1]benzothieno[3,2-b][1]benzothiophene, Tokyo Chemical Industry Co., Ltd., product code D5491, purity (test method): >99.5% (HPLC). Organic semiconductor layer additive raw material: polystyrene, Sigma-Aldrich, product code 182427, average Mw ~280,000 (GPC).

[0060] (Apparatus) Film formation apparatus: Spin coater (MS-A150, manufactured by Mikasa Co., Ltd.) i-line exposure machine: Multilight (manufactured by Ushio Inc.) Photolithography Weight average molecular weight: GPC (GPC-8020, manufactured by TOSO) Remaining film rate: Stylus profiler (P16, manufactured by KLA-Tencor Corporation) Evaluation of various electrical properties: Semiconductor parameter analyzer (4200A-SCS model, manufactured by Keithley Instruments)

[0061] (Evaluation methods) Average molecular weight: Calculated using GPC (TOSO: GPC-8020) Content of chalcone skeleton: Calculated from the charge ratio of synthetic raw materials Residual film ratio: Ratio of film thickness after exposure and development to film thickness before exposure Leakage current: Obtained by current-voltage (IV) measurement of Metal-Insulator-Metal structure using a semiconductor parameter analyzer Dielectric constant: Calculated from capacitance measurement of Metal-Insulator-Metal structure using a semiconductor parameter analyzer Transfer characteristics: Obtained using a semiconductor parameter analyzer Threshold voltage shift due to bias stress test: Obtained by a Negative Bias Stress (NBS) test in which a constant voltage (VGS = -20V) is applied between the source and gate. The application time was set to 1 second, 10 seconds, 100 seconds, and 1000 seconds, and the transfer characteristics were measured after each application time to calculate the difference in threshold voltage.

[0062] Synthesis Example 1 Synthesis of Compound Having a Hydroxy Group and a Methoxychalcone Skeleton (Compound 3 in Scheme 1) Compound 3: <Substance Name: 4'-Hydroxy-4-methoxychalcone> Under Ar, 4-hydroxyacetophenone (FUJIFILM Wako Pure Chemical Industries, Ltd., 390 g), p-anisaldehyde (FUJIFILM Wako Pure Chemical Industries, Ltd., 390 g), and methanol (FUJIFILM Wako Pure Chemical Industries, Ltd., 5.5 L) were mixed in a 20 L four-neck flask. Next, 50% aqueous NaOH solution (2.7 L) was added dropwise over 60 minutes while maintaining the internal temperature at 15°C or below in an ice bath. The ice bath was then removed, and the mixture was stirred at room temperature for 95 hours. 5.4 L of distilled water was placed in a 90 L container, and the reaction solution was poured into it. Next, 1 N aqueous HCl solution (approximately 35 L) was poured little by little. When the internal temperature was about to exceed 30°C, ice was added to maintain the temperature at about 25°C. The pH was adjusted to about 4, and the precipitated solid was collected by suction filtration. The solid was washed with a mixed solution of methanol and distilled water (2 / 1, 3 L). The resulting solid was dried under reduced pressure at 50°C for 24 hours to obtain 544.6 g of a pale yellow solid. Recrystallization was carried out using ethanol to obtain 520.8 g of the target product as a pale yellow solid (yield 71%). The results of 1H-NMR measurement of 4'-hydroxy-4-methoxychalcone are shown below. 1H-NMR (CDCl ３ ) 3.86 (3H, s), 5.52 (1H, s), 6.93 (4H, m), 7.41 (1H, m), 7.60 (2H, m), 7.81 (1H, m), 8.01 (2H, m)

[0063] Synthesis Example 2 Synthesis of an Ethylenically Unsaturated Compound Having a Methoxychalcone Skeleton (Compound 5 in Scheme 1) Compound 5: <Substance Name: (E)-4-(3-(4-Methoxyphenyl)acryloyl)phenyl methacrylate> 4'-Hydroxy-4-methoxychalcone (30.0 g) and THF (dry) were placed in a 2 L four-neck flask under argon and dissolved. Triethylamine (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd., 15.5 g) was added thereto, and the mixture was cooled with ice water. After that, methacryloyl chloride (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd., 14.8 g) was added dropwise, followed by stirring overnight. Water (600 mL) was poured into a reactor, transferred to a separatory funnel, and extracted with ethyl acetate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd., 1.2 L). Next, the ethyl acetate layer was washed twice with 5% aqueous sodium bicarbonate (600 mL) and three times with water (600 mL), and then dried over anhydrous sodium sulfate. After removing the desiccant, the mixture was concentrated under reduced pressure (40°C / 20 mmHg) to obtain a pale yellow solid. Ethanol (600 mL) was added to the obtained crude product, and the mixture was suspended and stirred for 30 minutes, then filtered to obtain a white solid. This was dried under reduced pressure (40°C / <1 mmHg) to obtain 30.1 g (79.2%) of the target product. The results of 1H-NMR measurement of (E)-4-(3-(4-methoxyphenyl)acryloyl)phenyl methacrylate are shown below. 1H-NMR (CDCl ３ ) 2.09 (3H, s), 3.87 (3H, s), 5.81 (1H, m), 6.39 (1H, m), 6.93 (2H, d), 7.26 (2H, d), 7.38 (1H, m), 7.63 (2H, d), 7.78 (1H, m), 8.08 (2H, d)

[0064] Synthesis Example 3: Synthesis of a polymer having a methoxychalcone skeleton (PMC: Poly(4-Methoxychalcone)) (Compound represented by the above formula (2), Compound 6 in Scheme 2) As shown in Scheme 2 above, Compound 6 was synthesized by polymerizing Compound 5 obtained in Synthesis Example 2. (E)-4-(3-(4-methoxyphenyl)acryloyl)phenyl methacrylate and degassed DMF were added to a 3 L four-neck flask under argon and stirred. AIBN (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 3.82 g) was added thereto, and the mixture was heated to 60°C and stirred for 21 hours. After cooling, the mixture was added dropwise to methanol (30 L). After stirring for 60 minutes, the mixture was filtered under reduced pressure and washed three times with methanol (2 L). The resulting solid was dried under reduced pressure (50°C / <1 mmHg) to obtain 135 g of the desired PMC. The results of the 1H-NMR measurement of PMC are shown below. ３ ) 1.57 (3H, br), 1.94 (1H, br), 3.75 (3H, br), 6.83 (2H, br), 7.31 (6H, m, br), 7.96 (2H, br) The weight average molecular weight, chalcone skeleton content, solid content, etc. of the obtained Compound 6 were evaluated, and the results are shown below. The evaluation method is as described above. Weight average molecular weight: 44131 Chalcone skeleton content: 74 parts by mass

[0065] Example 1 Preparation of Composition 3% by mass of chalcone and 10% by mass of polyvinyl cinnamate were dissolved in cyclopentanone to prepare the composition of this example.

[0066] [Preparation and Evaluation of Organic Insulating Film] Figure 3 is a schematic diagram of a Metal-Insulator-Metal structure prepared to examine the electrical properties of the organic insulating film obtained from the composition prepared in this example. Using the composition prepared in this example, a film was formed on a silicon wafer by spin coating at 2000 rpm for 60 seconds. The film thickness before photolithography was 450 nm. Pre-baking was performed at 80°C for 20 minutes, and the organic insulating film was exposed to various i-line exposure doses, and developed with PGMEA. Figures 4 and 5 (enlarged views of Figure 4) show the remaining film ratio versus exposure dose. As shown in Figure 5, the remaining film thickness was 2400 mJ / cm ２The remaining film ratio reached nearly 1. FIG. 6 shows the leakage current between the upper electrode and the lower electrode of the MIM structure shown in FIG. 3. From FIG. 6, it was found that the organic insulating film of Example 1 had almost the same insulating properties as the organic insulating film of Comparative Example 1 described below. The dielectric constant of the organic insulating film of Example 1 was also evaluated. The evaluation results of the organic insulating film of Example 1 are shown in Table 1.

[0067] [Fabrication and Evaluation of Organic Thin-Film Transistor] FIG. 7 shows a method for fabricating an organic thin-film transistor according to this embodiment. FIG. 2 is a schematic diagram of the laminated structure of the fabricated organic thin-film transistor. First, a gate electrode was formed in the process shown in FIG. 7(1). A 50-nm aluminum (Al) film was formed on a soda-lime wafer, an insulating substrate, by resistance heating vacuum deposition. Next, electrode processing was performed. First, a positive photoresist, Sumiresist PFI-34A (manufactured by Sumitomo Chemical), was spin-coated on the surface of the Al layer at 1500 rpm for 45 seconds, and the resist film was pre-baked at 105°C for 10 minutes to remove the solvent. Next, the gate electrode pattern was exposed to light using a photomask at an i-ray dose of 270 mJ / cm2, followed by post-exposure baking (PEB) at 105°C for 10 minutes. The exposed resist was then removed by immersion in tetramethylammonium hydroxide (TMAH) at room temperature (25°C) for 1 minute. The substrate was then washed with pure water and then pre-baked with N ２ The substrate was dried by blowing gas onto it and post-baked at 105° C. for 10 minutes. Next, the Al layer was processed. ３ P.O. ４ :CH ３ COOH:HNO ３ : H ２ The substrate was immersed in a solution of HCl (weight ratio: 10:1:1:2) and the exposed Al was etched. The resist on the substrate was removed with acetone, washed with pure water, and then immersed in N ２ The resulting film was dried by spraying gas onto it. Next, a gate insulating film was formed in the process shown in FIG. 7(2). The composition obtained in this example was spin-coated at 2000 rpm for 60 seconds to form a film, which was then pre-baked at 80°C for 20 minutes. Next, a photomask was used to apply an i-ray dose of 2400 mJ / cm. ２The substrate was then immersed in PGMEA developer at room temperature (25°C), and only the gate electrode pads were opened. This was followed by post-baking at 150°C for 1 hour. Next, source / drain electrodes were formed in the process shown in Figure 7(3). A 50-nm gold (Au) film was deposited on the gate insulating film (layer) using a resistance heating vacuum deposition method. Next, electrode processing was performed. Resist and etching processes were performed similarly to the process shown in Figure 7(1). Finally, a semiconductor layer was formed in the process shown in Figure 7(4). The substrate on which the source / drain electrodes were fabricated was UV-treated, and a thiol-based self-assembled monolayer (SAM) was formed on the Au electrode surface using a dipping method. Next, a semiconductor solution containing 0.5% by mass of organic semiconductor and 0.2% by mass of polystyrene dissolved in xylene was heated to 150°C, spin-coated at 1000 rpm for 30 seconds, and post-baked at 120°C for 5 minutes. Finally, the electrode pads were wiped to pattern the semiconductor layer. A microscope image of the completed OTFT is shown in Figure 8. Figure 9 shows the transfer characteristics and bias stress test results of the fabricated OTFT (channel length L = 50 μm, channel width W = 500 μm). The transfer characteristics were obtained at a source-drain voltage Vds = -2 V. The bias stress test involved applying a bias voltage Vg = -20 V between the source and gate, and obtaining data after 1 second, 10 seconds, 100 seconds, and 1000 seconds of application to obtain characteristic changes. Figure 10 shows the amount of threshold voltage shift versus application time. A threshold voltage shift of 0.5 V was observed in the gate insulating film of this example after 1000 seconds of application.

[0068] Examples 2 to 15 Preparation of Compositions Compositions of Examples 2 to 5 were prepared according to the formulations shown in Tables 1 and 2.

[0069] [Preparation and Evaluation of Organic Insulating Films] Organic insulating films were prepared and evaluated in the same manner as in Example 1, except that the compositions of Examples 2 to 15 were used instead of the composition of Example 1. The results are shown in Tables 1 and 2.

[0070] [Fabrication and Evaluation of Organic Thin Film Transistors] Organic thin film transistors were fabricated and evaluated in the same manner as in Example 1, except that the compositions of Examples 2 to 15 were used instead of the composition of Example 1. The results are shown in Tables 1 and 2.

[0071] Example 16 [Preparation of Composition] The polymerized methoxychalcone film obtained in Synthesis Example 3 was dissolved in cyclopentanone at 10% by mass to prepare the composition of this example.

[0072] [Preparation and Evaluation of Organic Insulating Film] Figure 3 is a schematic diagram of a Metal-Insulator-Metal structure prepared to examine the electrical properties of the organic insulating film obtained from the composition prepared in this example. Using the composition prepared in this example, a film was formed on a silicon wafer by spin coating at 2000 rpm for 60 seconds. The film thickness before photolithography was 450 nm. Pre-baking was performed at 80°C for 20 minutes, and the organic insulating film was exposed to various i-line exposure doses, and then developed with cyclopentanone. Figures 11 and 12 (enlarged views of Figure 11) show the remaining film ratio versus exposure dose. As shown in Figure 12, the remaining film thickness was 450 nm at 200 mJ / cm ２ The remaining film ratio reached nearly 1. FIG. 13 shows the leakage current between the upper electrode and lower electrode of the MIM structure shown in FIG. 3. From FIG. 13, it was found that the organic insulating film of Example 1 had almost the same insulating properties as the organic insulating film of Comparative Example 1 described below. The dielectric constant of the organic insulating film of Example 16 was also evaluated. The evaluation results of the organic insulating film of Example 16 are shown in Table 2.

[0073] [Fabrication and Evaluation of Organic Thin-Film Transistor] FIG. 7 illustrates a method for fabricating an organic thin-film transistor according to this embodiment. FIG. 2 is a schematic diagram of the laminate structure of the fabricated organic thin-film transistor. First, a gate electrode was formed in the process shown in FIG. 7(1). A 50-nm aluminum (Al) film was formed on a soda-lime wafer, an insulating substrate, by resistance heating vacuum deposition. Next, electrode processing was performed. First, a positive photoresist, Sumiresist PFI-34A (manufactured by Sumitomo Chemical), was spin-coated onto the surface of the Al layer at 1500 rpm for 45 seconds, and the resist film was prebaked at 105°C for 10 minutes to remove the solvent. Next, the gate electrode pattern was exposed to light using a photomask at an i-line dose of 270 mJ / cm2, followed by post-exposure baking (PEB) at 105°C for 10 minutes. The exposed resist was then removed by immersion in tetramethylammonium hydroxide (TMAH) at room temperature (25°C) for 1 minute. After washing the substrate with pure water, it was dried by blowing N2 gas and post-baked at 105°C for 10 minutes. Next, the Al layer was processed. ３ P.O. ４ :CH ３ COOH:HNO ３ : H ２ The substrate was immersed in a solution of HCl (weight ratio: 10:1:1:2) and the exposed Al was etched. The resist on the substrate was removed with acetone, washed with pure water, and then immersed in N ２ The resulting film was dried by spraying gas onto it. Next, a gate insulating film was formed in the process shown in FIG. 7(2). The composition obtained in this example was spin-coated at 2000 rpm for 60 seconds to form a film, which was then pre-baked at 80°C for 20 minutes. Next, a photomask was used to apply an i-ray dose of 2400 mJ / cm. ２The substrate was then immersed in cyclopentanone as a developer at room temperature (25°C), and only the gate electrode pads were opened. This was followed by post-baking at 150°C for 1 hour. Next, source / drain electrodes were formed in the process shown in Figure 7(3). A 50-nm gold (Au) film was formed on the gate insulating film (layer) using a resistance heating vacuum deposition method. Next, electrode processing was performed. Resist and etching processes were performed similarly to the process shown in Figure 7(1). Finally, a semiconductor layer was formed in the process shown in Figure 7(4). The substrate on which the source / drain electrodes were formed was UV-treated, and a thiol-based self-assembled monolayer (SAM) was formed on the Au electrode surface using a dipping method. Next, a semiconductor solution containing 0.5% by mass of organic semiconductor and 0.2% by mass of polystyrene dissolved in xylene was heated to 150°C, spin-coated at 1000 rpm for 30 seconds, and post-baked at 120°C for 5 minutes. Finally, the electrode pads were wiped to pattern the semiconductor layer. A microscope image of the completed OTFT is shown in Figure 13. Figure 15 shows the transfer characteristics and bias stress test results of the fabricated OTFT (channel length L = 50 μm, channel width W = 500 μm). The transfer characteristics were obtained at a source-drain voltage Vds = -2 V. The bias stress test involved applying a bias voltage Vg = -20 V between the source and gate, and obtaining data after 1 second, 10 seconds, 100 seconds, and 1000 seconds of application to obtain characteristic changes. Figure 10 shows the threshold voltage shift versus application time. A threshold voltage shift of 0.67 V was observed in the gate insulating film of this example after 1000 seconds of application.

[0074] Comparative Example 1 PVCi was dissolved in cyclopentanone at 10% by mass to prepare a composition of this comparative example.

[0075] [Preparation and Evaluation of Organic Insulating Film] An organic insulating film was prepared and evaluated in the same manner as in Example 1, except that the composition of this comparative example was used instead of the composition of Example 1 and the obtained organic insulating film was developed with PGMEA. The results are shown in Table 1.

[0076] [Fabrication and Evaluation of Organic Thin-Film Transistors] In Comparative Example 1, the gate insulating film was PVCi in the OTFT fabrication process described in Example 1. PVCi was dissolved in cyclopentanone at 10% by mass, and a film was formed by spin-coating at 2000 rpm for 60 seconds. The film was then pre-baked at 80°C for 20 minutes. The film was then fully cured using a low-pressure mercury lamp with a photomask. The film was then immersed in cyclopentanone at room temperature (25°C), and only the gate electrode pad portion was opened. The film was then post-baked at 150°C for 1 hour. Figure 16 shows the transfer characteristics and bias stress test results of the fabricated OTFT (channel length L = 50 μm, channel width W = 500 μm). The transfer characteristics were obtained at a source-drain voltage Vds = -2V. In the bias stress test, a bias voltage Vg of -20 V was applied between the source and gate, and data was collected after 1 second, 10 seconds, 100 seconds, and 1000 seconds to obtain characteristic changes. Figure 9 shows the amount of threshold voltage shift versus application time. For PVCi, a threshold voltage shift of 0.74 V was observed after 1000 seconds of application.

[0077]

[0078]

[0079] The symbols in the table have the following meanings: PVCi: polyvinyl cinnamate CH: chalcone MC: methoxychalcone PMC: poly(4-methoxychalcone) CPN: cyclopentanone PGMEA: propylene glycol 1-monomethyl ether 2-acetate

[0080] 1, 11: organic semiconductor layer 2, 12, 22: substrate 3, 13, 33: gate electrode 4, 14: gate insulating layer 5, 15, 35: source electrode 6, 16, 36: drain electrode 22: substrate 23: electrode 24: insulating layer

Claims

1. a chalcone compound; Polyvinyl cinnamate, A photosensitive organic insulating material composition comprising:

2. 2. The photosensitive organic insulating material composition according to claim 1, wherein the chalcone compound is at least one selected from the group consisting of chalcone and methoxychalcone.

3. 3. The photosensitive organic insulating material composition according to claim 1, wherein the ratio of the total mass of said chalcone compounds to the mass of said polyvinyl cinnamate is 0.01 to 1.

4. 3. The photosensitive organic insulating material composition according to claim 1, wherein a total amount of the chalcone compound and the polyvinyl cinnamate is 10% by mass to 30% by mass relative to 100% by mass of the total amount of the photosensitive organic insulating material composition.

5. 3. The photosensitive organic insulating material composition according to claim 1, wherein the total amount of the chalcone compounds is 0.1% by mass to 15% by mass with respect to 100% by mass of the total amount of the photosensitive organic insulating material composition.

6. 3. The photosensitive organic insulating material composition according to claim 1, which has an absorption spectrum peak in the wavelength range of 300 to 370 nm.

7. An insulating film which is a photocured product of the photosensitive organic insulating material composition according to claim 1 or 2.

8. A gate insulating film which is a photocured product of the photosensitive organic insulating material composition according to claim 1 or 2.

9. A transistor comprising the gate insulating film according to claim 8 .

10. An electronic device comprising the transistor of claim 9.

11. A step of applying the photosensitive organic insulating material composition according to claim 1 or 2 to a substrate; and curing the photosensitive organic insulating material composition by exposure to light to form a gate insulating film.

12. A method for manufacturing a transistor having a gate insulating film, comprising: A method for manufacturing a transistor, comprising the step of forming the gate insulating film by the method for manufacturing a gate insulating film according to claim 11.