WO2024189876A1

WO2024189876A1 - Photosensitive organic insulating material composition, insulating film, gate insulating film, transistor, electronic device, and method for manufacturing transistor

Info

Publication number: WO2024189876A1
Application number: PCT/JP2023/010262
Authority: WO
Inventors: 研太郎山田; 雄介川上; 翔平小泉
Original assignee: 株式会社ニコン
Priority date: 2023-03-16
Filing date: 2023-03-16
Publication date: 2024-09-19

Abstract

An objective of the present invention is to provide a photosensitive organic insulating composition having sufficient absorption, even of i-line rays, 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 polymer having a chalcone skeleton.

Description

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

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 manufacturing a transistor.

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 that uses polyvinyl cinnamate (also called poly(vinyl cinnamate), hereafter sometimes referred to as PVCi) which is a photosensitive resin material as a gate insulating film. However, when the light used for exposure is i-line (wavelength 365 nm), PVCi has problems such as very low absorption of i-line and requiring a very large exposure dose for curing when using a monochromatic i-line light source. Against this background, there has been a demand for a photosensitive organic insulating composition that has high i-line absorption while maintaining the same level of insulating properties as PVCi, and does not require a large exposure dose for curing even when using a monochromatic i-line light source.

A first aspect of the present invention is a photosensitive organic insulating material composition comprising a polymer having a chalcone skeleton.
A second aspect of the present invention is an insulating film which 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 which 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 according to the third aspect.
A fifth aspect of the present invention is an electronic device comprising 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 method for producing a gate insulating film according to the sixth aspect.

1 is a diagram showing cross-sectional shapes of organic thin-film transistors: (a) a bottom-gate-top-contact type organic thin-film transistor, (b) a bottom-gate-bottom-contact type organic thin-film transistor, (c) a top-gate-top-contact type organic thin-film transistor, and (d) a top-gate-bottom-contact type organic thin-film transistor. FIG. 1 is a schematic cross-sectional view showing the structure of a bottom-gate-bottom-contact type organic thin-film transistor according to a first embodiment. FIG. 2 is a schematic diagram of a Metal-Insulator-Metal structure produced to examine the electrical properties of the organic insulating film obtained from the composition prepared in Example 1. FIG. 1 is a graph showing the remaining film ratio versus exposure dose for the insulating films obtained in Examples 1 and 6 and Comparative Example 1. 4 is a diagram showing the remaining film ratio versus the exposure dose for the insulating films obtained in Examples 1 and 6 and Comparative Example 1. FIG. FIG. 4 is a diagram showing leakage current between the upper electrode and the lower electrode of the MIM structure shown in FIG. 3 in Examples 1 and 6 and Comparative Example 1. 1A and 1B are diagrams illustrating a method for producing an organic thin film transistor in Examples 1 and 16. FIG. 2 is a microscopic image of the OTFT completed in Example 1. 13 is a diagram showing the transfer characteristics of the fabricated OTFT and the results of a bias stress test. FIG. FIG. 13 is a diagram showing the results of V _TH shift amounts of the fabricated OTFTs. FIG. 13 is a graph showing the remaining film rate versus exposure dose for the insulating film obtained in Example 16. 11 is a graph showing the remaining film ratio versus the exposure dose for the insulating film obtained in Example 16. FIG. FIG. 4 is a diagram showing leakage current between the upper electrode and the lower electrode of the MIM structure shown in FIG. 3 in Example 16 and Comparative Example 1. FIG. 13 is a microscopic image of the OTFT completed in Example 16. The transfer characteristics and bias stress test results of the OTFT fabricated in Example 16 are shown. The transfer characteristics and bias stress test results of the OTFT fabricated in Comparative Example 1 are shown.

(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.

First Embodiment
The photosensitive organic insulating material composition of the first embodiment contains a chalcone compound and polyvinyl cinnamate (PVCi).

<Chalcone compounds>
The 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 an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a polyoxyalkyl group having 1 to 5 carbon atoms, an alkylamino group having 1 to 5 carbon atoms, a thioalkyl group having 1 to 5 carbon atoms, a sulfonyl group having 1 to 5 carbon atoms, a nitro group, and a cyano group. Among them, chalcones having one or more substituents selected from the group consisting of an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and a polyoxyalkyl group 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 in the benzene ring on the alkene side of the unsaturated carbonyl, and more preferably substituted at the ortho or para position. From the viewpoint of facilitating the photodimerization reaction and increasing the 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, and an alkoxy group having 1 to 3 carbon atoms is 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 the present embodiment may be used alone or in combination of two or more.

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

<Solvent>
The photosensitive organic insulating material composition of the present 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 preferable.

<Other ingredients>
To improve weather resistance and light resistance, known antioxidants, light stabilizers, and ultraviolet absorbers may be added. To improve adhesion, known adhesion promoters may be added. To improve leveling properties, surface wettability, or hydrophobicity, known surface modifiers may be added.

<Composition ratio of composition>
The photosensitive organic insulating material composition of the present embodiment may contain the above chalcone compound and polyvinyl cinnamate in the following mass ratio: The ratio of the total mass of the chalcone compound to the mass of 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 the present embodiment, the total amount of the chalcone compound and the 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 amount of the composition.
In the photosensitive organic insulating material composition of the present 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 amount of the composition.

<i-line sensitivity of composition>
The photosensitive organic insulating material composition of this embodiment preferably has an absorption spectrum peak in the wavelength range of 300 to 370 nm, more preferably has an absorption spectrum peak in the wavelength range of 320 to 370 nm, even more preferably has an absorption spectrum peak in the wavelength range of 340 to 370 nm, and most preferably has an absorption spectrum peak at i-line (365 nm). The photosensitive organic insulating material composition of this embodiment contains a chalcone compound in addition to polyvinyl cinnamate, so that the absorption at i-line is greater than when only polyvinyl cinnamate is contained. As a result, when an i-line exposure machine with the same light intensity is used, the time required for photocuring is shorter. The productivity can be greatly improved.
The light absorption intensity at i-line 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, the content is preferably 10% by mass to 50% by mass in 100% by mass of the components (solid content) excluding the solvent of the photosensitive organic insulating material composition. When the chalcone compound is methoxychalcone, the content is preferably 5% by mass to 25% by mass.

Second Embodiment
The photosensitive organic insulating material composition of the second embodiment contains a polymer having a chalcone skeleton.

<Polymers having chalcone skeleton>
The chalcone skeleton in the polymer according to this embodiment is a structure derived from 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 the preferred examples thereof are also the same. The chalcone skeleton 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 a 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.

The polymer having a chalcone skeleton according to this embodiment includes a vinyl polymer main chain and a side chain that includes a chalcone skeleton, and may also include a side chain that does not include a chalcone skeleton. It is preferable that the polymer having a chalcone skeleton according to this embodiment includes a vinyl polymer main chain and a side chain that includes a chalcone skeleton, and does not include any other side chains.

The polymer having a chalcone skeleton according to the present 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).

(In formula (1), n1 is an integer from 1 to 1000.)

(In formula (2), n2 is an integer from 1 to 1000.)

(In formula (3), n3 is an integer from 1 to 1000.)

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).

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 excluding the -OH group of compound 3 in the scheme below) 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.

<Method of producing polymer having 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 the above 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.

The above ethylenically unsaturated compound having a chalcone skeleton can be produced by a known method in which a compound having a hydroxy group and a chalcone skeleton is reacted with an acid chloride having an ethylenically unsaturated group in a solvent. For example, as shown in the following scheme 1, compound 3 is synthesized by the method described in Non-Patent Document 2. One method is to react the obtained phenol derivative compound 3 (or use 4'-hydroxy-4-methoxychalcone manufactured by Biosynth) with compound 4 to synthesize compound 5.

(Non-patent document 2: X. Yang et. al. Synthesis of a series of novel dihydroartemisinin derivatives containing a Substituted chalcone with greater cytotoxic effects in leukemia cells, Bioorganic & Medicinal Che mistry Letters, Volume 19, Issue 15, (2009), Pages 4385-4388.)

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 a known method such as solution polymerization, emulsion polymerization, suspension polymerization, or bulk polymerization.
The solvent used in the solution polymerization is not limited in any way as long as it dissolves the above-mentioned monomers and the polymer of the present invention. Examples of the solvent include toluene, xylene, diethyl ether, tetrahydrofuran, 1,4-dioxane, dimethylformamide, dimethyl sulfoxide, and the like. These solvents can also be used in combination.

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 limited in any way and is set according to the half-life of the initiator used, but from an economical standpoint, 4 to 30 hours is preferable.

For example, as shown in the following scheme 2, compound 6 is synthesized by polymerizing compound 5 obtained above.
The synthesis reaction conditions will be described in detail in the Examples, and the evaluation results of Compound 6 will also be described in the Examples.

In the above polymerization step, the ethylenically unsaturated monomers that are the raw materials for the polymerization reaction may contain, in addition to ethylenically unsaturated compounds having a chalcone skeleton such as compound 5 in Scheme 2 above, ethylenically unsaturated compounds not having a chalcone skeleton. When an ethylenically unsaturated compound not having a chalcone skeleton is contained, the side chains of the resulting polymer contain, in addition to side chains having a chalcone skeleton, side chains not having a chalcone skeleton. In that 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 parts by mass, relative to 100 parts by mass of the total mass of the ethylenically unsaturated compounds having a chalcone skeleton.

<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 preferable. In addition, the solvent used in the polymerization reaction may be used as it is as a part of the solvent of the composition.

<Composition ratio of composition>
In the photosensitive organic insulating material composition of the present embodiment, 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, based on 100% by mass of the components (solid content) excluding the solvent. The chalcone compound and polyvinyl cinnamate may be contained in the following mass ratio.
In the photosensitive organic insulating material composition of the present 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.

<i-line sensitivity of composition>
The photosensitive organic insulating material composition of this embodiment preferably has an absorption spectrum peak in the wavelength range of 300 to 370 nm, more preferably has an absorption spectrum peak in the wavelength range of 320 to 370 nm, even more preferably has an absorption spectrum peak in the wavelength range of 340 to 370 nm, and most preferably has an absorption spectrum peak at i-line (365 nm). Since the photosensitive organic insulating material composition of this embodiment contains a polymer having a chalcone skeleton, it has a higher absorption at i-line than the conventional technique containing only polyvinyl cinnamate. As a result, when using an i-line exposure machine with the same light intensity, the time required for photocuring is shorter. Productivity can be greatly improved.
The light absorption intensity of the photosensitive organic insulating material composition of this embodiment at i-line can be adjusted by the type of chalcone compound relative to the chalcone skeleton, the content of the chalcone skeleton in the polymer, etc. For example, when the chalcone compound is methoxychalcone, that is, when there is a polymer having a methoxychalcone skeleton, it is preferably 50 to 90 parts by mass. When the i-line absorption is large, the deep part curing property is reduced, and photocuring in a thick film and edge drawing property are reduced. The content can be adjusted arbitrarily to obtain excellent photocuring property at a desired film thickness.

(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 does not dissolve materials such as organic semiconductors used in the manufacture of devices such as organic thin film transistors, without any limitations. 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 iso-butanol; and 1-nitropropane, carbon disulfide, and limonene, and these solvents can be used in combination as necessary. It is preferable that the organic solvent is the same as the organic solvent for synthesis described above, and more preferable are propylene glycol 1-monomethyl ether 2-acetate (PGMEA), cyclopentanone, and the like.

There are no limitations on the coating or printing method, 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.

The composition according to the present embodiment has a photocrosslinking group having photodimerization reactivity, and radiation is preferably used for the photocrosslinking, and 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 preferable, and i-line monochromatic light source is more preferable. The radiation dose is appropriately changed depending on the composition of the polymer, and examples include 100 to 300 mJ/cm ² , and in order to prevent a decrease in the degree of crosslinking and improve the economy by shortening the process time, it is preferably 50 to 200 mJ/cm ^2. The environment when irradiating ultraviolet and visible light is not particularly limited, and it can be performed in the air, in an inert gas, or under a constant amount of inert gas flow. If necessary, a photosensitizer can be added to the composition to promote the photocrosslinking reaction. There is no limitation on the photosensitizer used, and examples include benzophenone compounds, anthraquinone compounds, thioxanthone compounds, and nitrophenyl compounds. In addition, the sensitizer can be used in combination of two or more types as necessary. In addition, from the viewpoint of enhancing the electrical properties of the organic insulating film of this embodiment, it is preferable that the composition does not substantially contain a photosensitizer. Here, the photosensitizer is a substance that plays a role in assisting the process of photocrosslinking reaction by transferring the energy obtained by absorbing light to another substance. Examples of the photosensitizer 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 amount is so small that no photosensitizing effect is observed. For example, in the composition according to the present embodiment, the amount is preferably in the range of 0 mass % to 0.05 mass %, more preferably in the range of 0 mass % to 0.01 mass %, even more preferably in the range of 0 mass % to 0.05 mass %, and even more preferably 0 mass %.

In addition, 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 using i-rays, it is preferable to set the light irradiation time to 2 minutes or less. In addition, since this is suitable for controlling the crosslinking time, for example, when using i-rays, it is even more preferable to set the light irradiation time to 1 minute or less.

The organic insulating film of this embodiment can be suitably used as an insulating film for various devices such as organic thin-film transistors. The organic insulating film of this embodiment can be suitably used as a gate insulating film for organic thin-film transistors, which will be described later.

(Organic thin-film transistor)

The organic thin-film transistor of this embodiment may have any of the device structures shown in FIG. 1, namely 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 applicable to devices of the types (A) and (B). In the examples, a device of the type (B) was used. Here, 1 is the organic semiconductor layer, 2 is the substrate, 3 is the gate electrode, 4 is the gate insulating layer, 5 is the source electrode, and 6 is the drain electrode.

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 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, aluminum, etc.; ceramics; coated paper; surface-coated nonwoven fabric, etc. Composite materials made of these materials or materials made by multilayering these materials may also be used. Furthermore, the surfaces of these materials can be coated to adjust the surface tension.

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. Two or more of the above plastics can also be laminated and used as the substrate.

Examples of the gate electrode, source electrode, or drain electrode that can be used in this embodiment include conductive materials such as gold, silver, aluminum, copper, titanium, platinum, chromium, polysilicon, silicide, indium tin oxide (ITO), and tin oxide. In addition, multiple layers of these conductive materials can be used.

In addition, in the case of bottom gate-top contact type (A) elements and bottom gate-bottom contact type (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. Methods such as solution spin coating, drop casting, dip coating, doctor blade, die coating, pad printing, roll coating, gravure printing, flexographic printing, screen printing, inkjet printing, and letterpress reverse printing can also be used using an ink in which nanoparticles of the conductive material are dissolved in water or an organic solvent. In addition, a treatment for adsorbing fluoroalkylthiol, fluoroarylthiol, or the like onto the electrode may be performed as necessary.

There are no limitations on the organic semiconductors that can be used in the organic thin-film transistor of this embodiment, and both N-type and P-type organic semiconductors can be used, and it can also be used as a bipolar transistor combining N-type and P-type. For example, polypyrroles, polythiophenes, polyanilines, polyallylamines, fluorenes, polycarbazoles, polyindoles, poly(p-phenylenevinylenes), etc. can be used. In addition, low molecular weight substances that are soluble in organic solvents, such as polycyclic aromatic derivatives such as pentacene, phthalocyanine derivatives, perylene derivatives, tetrathiafulvalene derivatives, tetracyanoquinodimethane derivatives, fullerenes, carbon nanotubes, etc. can be used. Specifically, examples include condensates of 9,9-di-n-octylfluorene-2,7-di(ethyleneboronate) and 5,5'-dibromo-2,2'-bithiophene.

In this embodiment, the method of forming the organic semiconductor layer is preferably a method of dissolving an organic semiconductor in an organic solvent and coating or printing the solution, but there are no limitations as long as a thin film of the organic semiconductor layer can be formed. The solution concentration 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 thickness of the layer, it is preferably 0.5 to 5% by weight. 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 of the organic solvent include hexane, heptane, octane, decane, dodecane, tetradecane, decalin, indane, 1-methylnaphthalene, 2-ethylnaphthalene, 1,4-dimethylnaphthalene, a mixture of dimethylnaphthalene isomers, 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, and γ-butyrolactone. , 1,3-butylene glycol, ethylene glycol, benzyl alcohol, glycerin, cyclohexanol acetate, 3-methoxybutyl acetate, ethylene 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-dichloro Examples include ethane, 1,1,2,2-tetrachloroethane, chloroform, dichloromethane, tetrahydrofuran, 1,2-dimethoxyethane, dioxane, cyclohexanone, acetone, methyl ethyl ketone, diethyl ketone, diisopropyl ketone, acetophenone, N,N-dimethylformamide, N-methyl-2-pyrrolidone, and limonene. In order to obtain a crystal film with preferred properties, a solvent that has 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 in which two or more of the above-mentioned solvents are mixed in an appropriate ratio can also be used.

Various organic and inorganic polymers or oligomers, or organic and inorganic nanoparticles can be added to the organic semiconductor layer as a solid or as a dispersion liquid in which nanoparticles are dispersed in water or an organic solvent, as required, and a protective film can be formed by applying the polymer solution onto the polymer dielectric layer. Furthermore, various types of moisture-proof coatings, light-resistant coatings, etc. can be applied to this protective film as required.

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 for use. In addition, in order to increase the carrier injection efficiency, surface treatment can be performed on these electrodes using a surface treatment agent. Examples of such surface treatment agents include benzenethiol and pentafluorobenzenethiol.

In addition, there are no particular limitations on the method for forming an electrode on the substrate, insulating layer, or organic semiconductor layer, and examples of the method 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, 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.

The organic thin-film transistor of this embodiment can be, for example, a bottom-gate-bottom-contact type element used in the examples. FIG. 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 therebetween, and an organic semiconductor layer 1 formed on the electrodes.

From the viewpoint of practicality of an organic thin film transistor element, the organic thin film transistor of this embodiment preferably has a mobility of 0.20 cm ² /Vs or more.

From the viewpoint of practicality of the organic thin-film transistor element, it is preferable that the threshold voltage of the organic thin-film transistor of this embodiment is -10.0 V or more and less than 0 V.

From the viewpoint of practicality of the organic thin film transistor element, the organic thin film transistor of this embodiment preferably has a leakage current density of 10 ⁻⁹ A/cm ² or less.

(Electronic devices including organic thin film transistors)
The electronic device of the present embodiment includes the organic thin film transistor of the present embodiment. Examples of the electronic device of the present embodiment include an organic electroluminescence element, an organic photoelectric conversion element, and a display.

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

The following describes the raw materials, equipment, etc. used in the examples of the present invention.

(Raw materials)
Chalcon: 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 1Ωcm 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)

(Device)
Film forming device: Spin coater (MS-A150, manufactured by Mikasa Co., Ltd.)
i-line exposure machine: Multilight (manufactured by Ushio Inc.)
Photolithography Weight average molecular weight: GPC (TOSO: GPC-8020)
Remaining film rate: Stylus profiler (KLA-Tencor: P16)
Evaluation of electrical characteristics: Semiconductor parameter analyzer (Keithley Instruments: 4200A-SCS model)

(Evaluation Method)
Average molecular weight: Calculated by GPC (TOSO: GPC-8020) Content of chalcone skeleton: Calculated from the ratio of synthetic raw materials used 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 using a Negative Bias Stress (NBS) test that applies a constant voltage (VGS = -20V) 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.

(Synthesis Example 1)
"Synthesis of a compound having a hydroxy group and a methoxychalcone skeleton (compound 3 in the above 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% NaOH aqueous solution (2.7 L) was added dropwise over 60 minutes while maintaining the internal temperature at 15°C or less 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, 1N HCl aqueous solution (approximately 35 L) was poured in little by little. If 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 separated by suction filtration, washed with a mixed solution of methanol and distilled water (2/1, 3 L), and the obtained solid was dried under reduced pressure at 50° C. for 24 hours to obtain 544.6 g of a pale yellow solid. Recrystallization was performed 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)

(Synthesis Example 2)
"Synthesis of an ethylenically unsaturated compound having a methoxychalcone skeleton (compound 5 in the above 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 added to a 2L four-neck flask under argon and dissolved. Triethylamine (FUJIFILM Wako Pure Chemical Industries, Ltd., 15.5 g) was added thereto, and after cooling with ice water, methacryloyl chloride (FUJIFILM Wako Pure Chemical Industries, Ltd., 14.8 g) was added dropwise, and then stirred overnight. Water (600 mL) was poured into the reactor, and then transferred to a separatory funnel and extracted with ethyl acetate (FUJIFILM Wako Pure Chemical Industries, Ltd., 1.2 L). Next, the ethyl acetate layer was washed twice with 5% sodium bicarbonate water (600 mL) and three times with water (600 mL), and then dried with 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, and 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 desired 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)

(Synthesis Example 3)
"Synthesis of 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 is synthesized by polymerizing compound 5 obtained in Synthesis Example 2.
In a 3 L four-neck flask, (E)-4-(3-(4-methoxyphenyl)acryloyl)phenyl methacrylate and degassed DMF were added under argon and stirred. AIBN (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 3.82 g) was added thereto, and the temperature was raised to 60° C. and the mixture was heated 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 obtained solid was dried under reduced pressure (50° C./<1 mmHg) to obtain 135 g of the target PMC.
The results of 1H-NMR measurement of PMC are shown below.
1H-NMR (CDCl 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, the content of the chalcone skeleton, the 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
Content of chalcone skeleton: 74 parts by mass

Example 1
[Preparation of Composition]
The composition of this example was prepared by dissolving 3% by mass of chalcone and 10% by mass of polyvinyl cinnamate in cyclopentanone.

[Creation and evaluation of organic insulating films]
FIG. 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. FIG. 4 and FIG. 5 (an enlarged view of FIG. 4) show the remaining film ratio versus exposure dose. As shown in FIG. 5, the remaining film ratio reached almost 1 at 2400 mJ/ ^cm2 .
FIG. 6 shows the leakage current between the upper electrode and the lower electrode of the MIM structure shown in FIG.
It is apparent from FIG. 6 that the organic insulating film of Example 1 has 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.

[Fabrication and evaluation of organic thin-film transistors]
Fig. 7 shows a method for producing an organic thin film transistor according to this embodiment, and Fig. 2 is a schematic diagram of a laminated structure of the produced organic thin film transistor.
First, a gate electrode was formed in the process of FIG. 7(1). A 50 nm thick aluminum (Al) film was formed on a soda lime wafer, which is an insulating substrate, by a resistance heating vacuum deposition method. 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 pre-baked at 105°C for 10 minutes to remove the solvent from the resist film. Next, the gate electrode pattern was exposed to light with an i-line dose of 270 mJ/cm2 using a photomask, and post-exposure baking (PEB) was performed at 105°C for 10 minutes. After that, the exposed resist was removed by immersing the substrate in tetramethylammonium hydroxide (TMAH) at room temperature of 25°C for 1 minute. After washing the substrate with pure water, _N2 gas was sprayed on the substrate to dry it, and post-baked at 105°C for 10 minutes. Next, the Al layer was processed. _The substrate was immersed in a heated mixed acid solution ( _H3PO4 : _CH3COOH : _HNO3 : _H2O = 10:1:1:2 weight ratio) to etch the exposed Al. The resist on the substrate was removed with acetone, washed with pure water, and then dried by blowing _N2 gas onto the substrate.
Next, a gate insulating film was formed in the process of FIG. 7(2). The composition obtained in this example was spin-coated at 2000 rpm for 60 seconds, and pre-baked at 80° C. for 20 minutes. Next, a photomask was used to harden the film with an i-ray dose of 2400 mJ/cm ^2. After that, the film was immersed in PGMEA as a developer at room temperature of 25° C., and only the pad portion of the gate electrode was opened. Then, the film was post-baked at 150° C. for 1 hour.
Next, source/drain electrodes were formed in the process of Fig. 7 (3). A gold (Au) film was formed to a thickness of 50 nm on the gate insulating film (layer) by resistance heating vacuum deposition. Next, electrodes were processed. Resist and etching processes were carried out in the same manner as in the process of Fig. 7 (1).
Finally, the semiconductor layer was formed in the process of FIG. 7(4). After the substrate on which the source/drain electrodes were formed was UV-treated, a thiol-based self-assembled monolayer (SAM) was formed on the surface of the Au electrode by immersion. Then, a semiconductor solution in which 0.5% by mass of organic semiconductor and 0.2% by mass of polystyrene were dissolved in xylene was heated to 150° C., and a film was formed by spin-coating at 1000 rpm for 30 seconds, and post-baked at 120° C. for 5 minutes. Finally, the semiconductor layer was patterned by wiping each electrode pad. A microscope image of the completed OTFT is shown in FIG. 8.
Fig. 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 was performed by applying a bias voltage Vg = -20 V between the source/gate, and obtaining the characteristic changes after 1 second, 10 seconds, 100 seconds, and 1000 seconds of application. Fig. 10 shows the shift in threshold voltage versus application time. In the gate insulating film of this example, a threshold voltage shift of 0.5 V was confirmed after 1000 seconds of application.

(Examples 2 to 15)
[Preparation of Composition]
Compositions of Examples 2 to 5 were prepared according to the compositions shown in Tables 1 and 2.

[Creation 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.

[Fabrication and evaluation of organic thin-film transistors]
Organic thin film transistors were produced 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.

(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.

[Creation and evaluation of organic insulating films]
FIG. 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. The film was prebaked at 80°C for 20 minutes, exposed to various i-line exposure doses, and the organic insulating film was developed with cyclopentanone. FIG. 11 and FIG. 12 (an enlarged view of FIG. 11) show the remaining film ratio versus exposure dose. As shown in FIG. 12, the remaining film ratio reached almost 1 at 200 mJ/ ^cm2 .
FIG. 13 shows the leakage current between the upper electrode and the lower electrode of the MIM structure shown in FIG.
It is apparent from FIG. 13 that the organic insulating film of Example 1 has 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.

[Fabrication and evaluation of organic thin-film transistors]
Fig. 7 shows a method for producing an organic thin film transistor according to this embodiment, and Fig. 2 is a schematic diagram of a laminated structure of the produced organic thin film transistor.
First, a gate electrode was formed in the process of FIG. 7(1). A 50 nm thick aluminum (Al) film was formed on a soda lime wafer, which is an insulating substrate, by a resistance heating vacuum deposition method. 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 pre-baked at 105°C for 10 minutes to remove the solvent from the resist film. Next, the gate electrode pattern was exposed to light using a photomask at an i-line dose of 270 mJ/cm2, and post-exposure baked (PEB) was performed at 105°C for 10 minutes. After that, the exposed resist was removed by immersing the substrate in tetramethylammonium hydroxide (TMAH) at room temperature of 25°C for 1 minute. The substrate was washed with pure water, dried by blowing N2 gas, and post-baked at 105°C for 10 minutes. Next, the Al layer was processed. _The substrate was immersed in a heated mixed acid solution ( _H3PO4 : _CH3COOH : _HNO3 : _H2O = 10:1:1:2 weight ratio) to etch the exposed Al. The resist on the substrate was removed with acetone, washed with pure water, and then dried by blowing _N2 gas onto the substrate.
Next, a gate insulating film was formed in the process of FIG. 7(2). The composition obtained in this example was spin-coated at 2000 rpm for 60 seconds, and pre-baked at 80° C. for 20 minutes. Next, a photomask was used to harden the film with an i-ray dose of 2400 mJ/cm ^2. After that, the film was immersed in cyclopentanone as a developer at room temperature of 25° C., and only the pad portion of the gate electrode was opened. Then, the film was post-baked at 150° C. for 1 hour.
Next, source/drain electrodes were formed in the process of Fig. 7 (3). A gold (Au) film was formed to a thickness of 50 nm on the gate insulating film (layer) by resistance heating vacuum deposition. Next, electrodes were processed. Resist and etching processes were carried out in the same manner as in the process of Fig. 7 (1).
Finally, the semiconductor layer was formed in the process of FIG. 7(4). After the substrate on which the source/drain electrodes were formed was UV-treated, a thiol-based self-assembled monolayer (SAM) was formed on the surface of the Au electrode by immersion. Then, a semiconductor solution in which 0.5% by mass of organic semiconductor and 0.2% by mass of polystyrene were dissolved in xylene was heated to 150° C., and a film was formed by spin-coating at 1000 rpm for 30 seconds, and post-baked at 120° C. for 5 minutes. Finally, the semiconductor layer was patterned by wiping each electrode pad. A microscope image of the completed OTFT is shown in FIG. 13.
FIG. 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=-2V. The bias stress test was performed by applying a bias voltage Vg=-20V between the source/gate, and the characteristics were obtained after 1 second, 10 seconds, 100 seconds, and 1000 seconds of application. FIG. 10 shows the shift in threshold voltage versus application time. In the gate insulating film of this example, a threshold voltage shift of 0.67 V was confirmed after 1000 seconds of application.

(Comparative Example 1)
PVCi was dissolved in cyclopentanone at 10% by mass to prepare the composition of this comparative example.

[Creation and evaluation of organic insulating films]
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.

[Fabrication and evaluation of organic thin-film transistors]
As Comparative Example 1, in the OTFT manufacturing process of Example 1, the gate insulating film was PVCi. PVCi was dissolved in cyclopentanone at 10 mass %, and a film was formed by spin coating at 2000 rpm for 60 seconds, and pre-baked at 80°C for 20 minutes. Next, the film was sufficiently cured with a low-pressure mercury lamp using a photomask. After that, the film was immersed in cyclopentanone at room temperature of 25°C, and only the pad portion of the gate electrode was opened. Then, the film was 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. The bias stress test was performed by applying a bias voltage Vg = -20V between the source/gate, and the characteristics were obtained after 1 second, 10 seconds, 100 seconds, and 1000 seconds of application. Figure 9 shows the shift in threshold voltage versus application time. For PVCi, a threshold voltage shift of 0.74V was confirmed after 1000 seconds of application.

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

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

A photosensitive organic insulating material composition comprising a polymer having a chalcone skeleton.
The photosensitive organic insulating material composition according to claim 1, wherein the polymer having a chalcone skeleton is a polymer or copolymer of a monomer containing a substituted chalcone compound having an ethylenically unsaturated group.
The photosensitive organic insulating material composition according to claim 2, wherein the substituted chalcone compound having an ethylenically unsaturated group is 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.
2. The photosensitive organic insulating material composition according to claim 1, wherein the polymer having a chalcone skeleton is any one of compounds represented by the following general formulas (1) to (3):

(In formula (1), n1 is an integer from 1 to 1000. In formula (2), n2 is an integer from 1 to 1000. In formula (3), n3 is an integer from 1 to 1000.)
The photosensitive organic insulating material composition according to any one of claims 1 to 4, having a weight average molecular weight of 5,000 to 100,000.
The photosensitive organic insulating material composition according to any one of claims 1 to 5, having an absorption spectrum peak in the wavelength range of 300 to 370 nm.
An organic insulating film that is a photocured product of the photosensitive organic insulating material composition according to any one of claims 1 to 6.
A gate insulating film that is a photocured product of the photosensitive organic insulating material composition according to any one of claims 1 to 6.
A transistor having the gate insulating film according to claim 8.
An electronic device having the transistor according to claim 9.
A step of applying the photosensitive organic insulating material composition according to any one of claims 1 to 6 onto a substrate;
and curing the photosensitive organic insulating material composition by exposure to light to form a gate insulating film.
A method for manufacturing a transistor having a gate insulating film, comprising the steps of:
A method for manufacturing a transistor, comprising the step of forming the gate insulating film by the method for manufacturing the gate insulating film according to claim 11.