JP2008170515A - Surface treatment material, substrate, and method of treating surface of substrate, thin film transistor, and method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a patterning method of high production efficiency in high precision of an organic semiconductor layer or a thin film such as a conductive film, and to provide an organic TFT of high performance of high mobility and a method of manufacturing the organic TFT of high production efficiency in high precision. <P>SOLUTION: A surface treatment material has a protection group decomposed under existence of acid in a molecule. A method of highly precisely obtaining a pattern of a conductive thin film such as an electrode film with excellent reproducibility by performing formation of the organic semiconductor layer having high carrier mobility with excellent production efficiency at the same time is provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a surface treatment material that provides a patterning method with high production efficiency of a thin film such as an organic semiconductor layer or a conductive film, a substrate treated thereby, and a method of manufacturing a semiconductor device using the same.

  With the widespread use of information terminals, there is an increasing need for flat panel displays as computer displays. In addition, with the progress of computerization, the information that has been provided in paper media has been increasingly digitized. As a mobile display medium that is thin, light, and easy to carry, it has become electronic paper or digital paper. Needs are growing.

  In general, in a flat display device, a display medium is formed using an element utilizing liquid crystal, organic EL, electrophoresis, or the like. In such a display medium, a technique using an active drive element formed of a thin film transistor (TFT) as an image drive element has become mainstream in order to ensure uniformity of screen brightness, screen rewrite speed, and the like.

  Here, the TFT element is usually formed on a glass substrate, mainly a semiconductor thin film such as a-Si (amorphous silicon) or p-Si (polysilicon), or a metal thin film such as a source, drain, or gate electrode on the substrate. Manufactured by sequentially forming. The production of flat panel displays using TFTs usually requires high-precision photolithographic processes in addition to vacuum equipment such as CVD and sputtering and thin film forming processes that require high-temperature processing processes. The load is very large. Furthermore, along with the recent needs for larger display screens, their costs have become enormous.

  In recent years, research and development of organic TFT elements using organic semiconductor materials has been actively promoted as a technique to compensate for the disadvantages of conventional TFT elements. Since this organic TFT element can be manufactured by a low temperature process, a light and hard-to-break resin substrate can be used, and a flexible display using a resin film as a support can be realized. Further, by using an organic semiconductor material that can be manufactured by a wet process such as printing or coating under atmospheric pressure, a display with excellent productivity and a very low cost can be realized.

  In order to produce a high-quality organic TFT with high mobility, it is necessary to form a good interface between the gate insulating film and the organic semiconductor layer, such as octadecyltrichlorosilane (OTS) or hexamethyldisilazane (HMDS). Attempts have been made to modify the surface of the gate insulating film with a treating agent to form a self-assembled monomolecular film (SAM film) (see, for example, Patent Documents 1, 2, and 3).

  However, in these methods, the mobility is still low, and when the surface treatment is applied, the organic semiconductor solution is repelled, the applicability is greatly reduced, and a good organic semiconductor layer cannot be provided. There has been a problem that semiconductor patterns cannot be accurately formed.

  In addition, a photodegradable material is used for the surface treatment layer (SAM film) of the gate insulating film, the exposed portion is hydrophilized, and hydrophilic electrode materials (solution, silver paste, etc.) are supplied, and the organic semiconductor thin film In addition, there is one that forms an electrode or the like (Patent Document 4).

However, even if these methods are used, the photosensitive wavelength is short and the sensitivity is low, so that the exposure and patterning methods are complicated, and the performance of the organic TFT such as carrier mobility is deteriorated.
JP 2004-327857 A International Publication No. 04/114371 Pamphlet JP 2005-158765 A JP 2005-79560 A

  Accordingly, an object of the present invention is to provide a patterning method with high precision and high production efficiency of a thin film such as an organic semiconductor layer or a conductive film. It is another object of the present invention to provide a high-performance organic TFT with high mobility and a method for manufacturing an organic TFT with high accuracy and high production efficiency.

  The above object of the present invention is achieved by the following means.

  1. A surface treatment material having a protecting group in the molecule that decomposes in the presence of an acid.

  2. 2. A substrate comprising a surface to which the surface treatment material according to 1 is bonded or bonded, and a film for supplying an acid to the surface.

  3. 3. The substrate according to 2 above, wherein the acid supplying film generates acid by the action of light or heat.

  4). 4. The substrate according to 3 above, wherein the acid supplying film contains a photoacid generator.

  5. 5. The substrate according to 4 above, wherein the acid supplying film contains a dye having a function of spectrally sensitizing the photoacid generator.

  6). 2. A thin film transistor, wherein the surface treatment material according to 1 is bonded or bonded to a surface of a gate insulating film.

  7. 3. The film for supplying acid in the substrate according to the above item 3, wherein the film for supplying acid is removed after image-wise acid is generated by applying image-wise light or heat to the film for supplying acid. A method for treating a substrate surface.

  8). 8. A method for producing a semiconductor device, comprising: forming a pattern of a semiconductor film or an electrode in a region where an acid is formed in an image-like manner using the substrate surface treatment method according to 7 above.

  The present invention provides a method for forming an organic semiconductor layer having a high carrier mobility with high production efficiency and at the same time obtaining a pattern of a conductive thin film such as an electrode film with high accuracy and good reproducibility.

  The best mode for carrying out the present invention will be described below, but the present invention is not limited thereto.

  First, a surface treatment material having a protecting group in the molecule that decomposes in the presence of an acid according to the present invention will be described.

  In the present invention, the surface treatment material chemically reacts with a film formation surface such as a silica surface to form a bond, thereby forming a so-called self-assembled monomolecular film and changing the surface energy of the film surface.

  Here, the self-assembled film is a film of a compound having a functional group capable of bonding with a constituent atom on the film forming surface (for example, a compound in which the functional group is bonded to a linear molecule) in a gas or liquid state. By coexisting with the formation surface, the functional group is a dense monomolecular film formed by adsorbing or binding to the constituent atoms of the film formation surface and directing the straight-chain molecules outward. This monomolecular film is referred to as a self-assembled film because it is formed by spontaneous chemical adsorption on the film forming surface of the compound.

  Regarding the self-assembled film, A.I. Chapter 3 of "An Introduction to Ultrathin Organic Film from Langmuir-Blodgett to Self-Assembly" by Ulman (Academic Press Inc. Boston, 1991).

  In the present invention, the surface state of the substrate is prepared by forming such a self-assembled film (SAM film). That is, by forming a self-assembled monomolecular film, it is in a state having an affinity for the thin film forming material on the substrate.

  As a surface treatment material that forms a self-assembled monomolecular film (SAM film) by reacting with such a film formation surface, in the present invention, a surface treatment material having a protecting group in the molecule that decomposes in the presence of an acid. Is used.

  In the present invention, the functional group capable of binding to the constituent molecules on the film forming surface is preferably a group such as alkoxysilane or halogenosilane, and the surface treatment material compound is preferably a so-called silane coupling agent.

  The surface treatment material of the present invention is preferably a compound represented by the following general formula.

_{(X) 3 Si- (L 1} ) -Y-R
Here, X represents a group selected from an alkoxy group, a halogen atom, and an isocyanate group, and the alkoxy group is preferably a lower alkoxy group having 1 to 4 carbon atoms. Of the halogen atoms, a chlorine atom is preferred. Here, L ₁ represents a divalent linking group selected from an alkylene group, a cycloalkylene group, an alkenylene group, an alkyne-diyl group, an arylene group, and a group consisting of a combination thereof.

  -Y-R represents a group that can be decomposed and removed by an acid, and Y may be any group as long as it is hydrolyzable, but is preferably an oxycarbonyloxy group, an acetal (ketal) bonding group, or a siloxane bonding group Etc.

The acetal (ketal) linking group is a group represented by the following structure,
—O—C (R ₁ ) (R ₂ ) —O—
R ₁ and R ₂ each represent a hydrogen atom, an alkyl group (preferably having 1 to 6 carbon atoms), an alkylene group (preferably having 1 to 6 carbon atoms), an aryl group, preferably a phenyl group, and each having a substituent. You may have. R ₁ and R ₂ may be bonded to each other to form a 4- to 7-membered carbon ring such as a cyclohexane ring or cyclopentane.

A siloxane bond is a group represented by the following structure:
—O—Si (R ₁ ) (R ₂ ) —O—
Here, R ₁ and R ₂ each represents an alkyl group (preferably having 1 to 6 carbon atoms).

  In the compound represented by the above general formula, R is an alkyl, alkenyl, alkynyl group, alkenyl group, or aryl group having 1 to 22 carbon atoms bonded through the decomposable group Y. Further, these groups may be substituted with each other. These alkyl, alkenyl, and alkynyl groups are preferably alkyl, alkenyl, alkynyl, and alkenyl groups having 4 to 22 carbon atoms, and the aryl group is preferably a phenyl group or a naphthyl group. These groups may be further substituted with a group such as an alkoxy group or an aryloxy group, or a fluorine atom.

  These surface treatment materials have a hydrolyzable group (Y), and the -Y-R group is removed (in the presence) by contact with an acid, and a hydroxy group is generated at the terminal instead.

  Examples of these surface treatment materials are given below.

  A typical synthesis example of these surface treatment materials is shown below. Other compounds can also be synthesized by similar known methods known in the synthesis of silane coupling agents.

  (Synthesis of Surface Treatment Material Illustrative Compound 7)

  1,1-dimethoxycyclohexane (0.5 mol), phenylcellosolve (0.5 mol) and 80 mg of p-toluenesulfonic acid (TsOH) were reacted at 100 ° C. for 1 hour with stirring, and then gradually increased to 150 ° C. The temperature was raised and the reaction was further continued at 150 ° C. for 4 hours. Methanol produced by the reaction was distilled off during this time. After cooling, further 5-hexen-1-ol (0.5 mol) was added and reacted again at 100 ° C. for 1 hour, then the temperature was gradually raised to 150 ° C. and further reacted at 150 ° C. for 4 hours. . After cooling, 500 ml of tetrahydrofuran (THF) and 2.5 g of anhydrous potassium carbonate were added and stirred and filtered. The solvent was distilled off from the filtrate under reduced pressure to obtain a viscous oily intermediate.

  Next, the intermediate (0.2 mol), trimethoxysilane (0.3 mol), THF (tetrahydrofuran) 250 ml, and tetrakis (triphenylphosphine) platinum (0.2 mol) were mixed under nitrogen. And reacted at 50 ° C. for 8 hours. After cooling, THF is distilled off under reduced pressure, and then diluted again with hexane, filtered through Celite to remove (tetrakistriphenylphosphine) platinum, and hexane is distilled off again under reduced pressure. Exemplified compound 7 was obtained as a viscous oily substance.

  In these surface treatment materials, it is considered that alkoxysilane or trichlorosilane reacts with a film-forming surface having a hydroxyl group such as silicon oxide and chemically bonds as shown below. The self-assembled monolayer (SAM film) formed in this way has a group in the molecule that the surface treatment material itself can be decomposed by an acid. A self-assembled monolayer having a hydroxy group is obtained.

  As a result, the surface energy of the substrate (film formation surface) undergoes a large change. For example, when forming an organic semiconductor layer or an electrode by a solution process such as coating or ink jetting, the affinity greatly changes, so that the position accuracy is high. High formation is possible.

  In order to form, for example, a gate insulating layer or a self-assembled monolayer on the substrate surface using the surface treatment material of the present invention, these surface treatment material solutions are prepared by spin coating, screen printing, ink jet, It can form by apply | coating using various solution processes, such as application | coating using various coaters, a dipping method, a spray method, and washing | cleaning and drying. Moreover, when it can vaporize, it can also be made to react by heating vaporization contact.

  Surface treatment with the surface treatment material of the present invention having a highly hydrophobic group such as an alkyl group via a hydrolyzable protecting group greatly reduces the surface energy of the substrate surface.

  By incorporating a mechanism for generating an acid in a predetermined region, the self-assembled monolayer on the surface of the substrate in contact with the acid generated in the predetermined region is hydrolyzed and the hydrophobic group is deprotected and removed. Thus, a self-assembled monolayer having a hydroxy group at the terminal is formed.

  As a result, the surface energy is increased in the acid generation region, and the affinity for the semiconductor solution and the electrode material is improved.

  Therefore, by performing acid generation according to a pattern, for example, when forming an organic semiconductor layer by a solution process or forming an electrode layer by applying an electrode material, this can be performed with high accuracy and good reproducibility. Moreover, since the orientation of the organic semiconductor material of the organic semiconductor layer is improved because the organic semiconductor layer is formed using the self-assembled monomolecular film (SAM film), an excellent semiconductor thin film with high mobility can be obtained.

  The acid may be any method according to a method of supplying the acid in a desired pattern on the substrate on which the self-assembled monolayer is formed by the surface treatment material. For example, the acid may be supplied by an ink jet method or a printing method.

  In order to cope with positional accuracy and liquid repellency, it is desirable to use an impregnated layer containing a compound that generates an acid by heat or light. A thin film containing a compound that generates acid by heat or light is formed on a substrate, and a thin film that generates acid by heat or light is irradiated with a heat or light pattern to generate an acid in the irradiated portion. That's fine.

  As a compound that generates an acid by light or heat, a material that can generate a proton acid is used, but as a material that can generate a proton acid, a layer containing an acid component such as carboxylic acid, sulfonic acid, phosphoric acid, There are materials that can generate an acid by heat or light, such as a photoacid generator and a thermal acid generator. A layer containing these materials is formed in contact with the SAM film formed on the substrate, and, for example, a function of supplying proton acid to a layer containing materials capable of generating the proton acid by heating is imparted.

  From the viewpoint of film formability, the acid generator may be a known resin containing a protonic acid such as a novolak, a resol, a phenol resin such as a vinylphenol polymer, an acrylic resin containing an acrylic acid component, or polystyrene sulfonic acid. It is preferable to use various resin layers such as a phenol resin, an acrylic resin, and an epoxy resin containing a photoacid generator.

  In the present invention, it is preferable to use a photoacid generator. Examples of the photoacid generator include onium salts such as diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, triazines having a halogen-substituted alkyl group, and halogen-substituted compounds. Organic halogen compounds capable of forming hydrohalic acids known as photoinitiators such as oxadiazoles having an alkyl group, orthoquinone-diazide compounds such as o-naphthoquinonediazito-4-sulfonic acid halides and their derivatives, etc. Various known compounds and mixtures may be mentioned, and s-triazines and oxadiazoles having a halogen-substituted alkyl group are particularly preferable. Specific examples thereof include the following 2-halomethyl-1,3,4-oxadiazole compounds and 2-halomethyl-1,3,4-oxadiazole compounds.

  In the present invention, in order to constitute an acid generation source, these photoacid generators are in contact with the SAM film in a mixed state (dissolved or dispersed) with various resins such as phenol resin, acrylic resin, and epoxy resin. To form a thin film. The organic binder is not particularly limited as long as it has a good film forming property and is an inert resin. For example, acrylic (methacrylic) resin such as polymethyl methacrylate, vinyl resin such as polyvinyl chloride, vinyl acetate resin, polyvinyl butyral resin, etc. In addition, water-soluble resins such as polyvinyl alcohol and gelatin are also used. Phenol resins such as novolak, resol, vinylphenol polymers, acrylic resins containing an acrylic acid component, and the like are also preferably used.

  The content of the photoacid generator in the acid generator thin film can vary widely depending on its chemical properties and the composition or physical properties of the acid generator layer of the present invention. A range of about 0.1 to about 20% by mass is appropriate, and a range of 0.2 to 10% by mass is preferable.

  As an exposure means for decomposing the photoacid generator, any method such as a xenon lamp, a mercury lamp, a fluorescent lamp, and various lasers can be used.

  Various sensitizing dyes may be added to the layer containing the photoacid generator to cause spectral sensitization. The efficiency of acid generation can be improved. Such sensitizing dyes include cyanine dyes, squalium dyes, merocyanine dyes, croconium dyes, azurenium dyes, phthalocyanine dyes, naphthalocyanine dyes, polymethine dyes, naphthoquinone dyes, thiopyrylium dyes, dithiols. Examples thereof include metal complex dyes, anthraquino dyes, indoaniline metal complex dyes, and intermolecular CT dyes. For example, by using an infrared absorbing dye having absorption at a wavelength of 700 nm or more, for example, the following cyanine dye (separate paper) and irradiating with a semiconductor laser, an acid can be selectively generated in an arbitrary region.

  Preferred examples of the dye having absorption in the infrared include the following.

  Further, infrared absorbing dyes described in JP-A-9-171254 and the like can also be mentioned. These layers may contain a photothermal conversion agent such as carbon black or magnetic powder. Further, a thermal acid generator may be included.

  A method of generating an acid thermally can be used by irradiating such a film that supplies an acid to the film surface with any high-density energy light suitable for the absorption wavelength of the photothermal conversion agent. For example, using an infrared absorber having an absorption peak of 700 or more, acid is generated by performing flash exposure with a xenon lamp, a halogen lamp, a mercury lamp, or the like through a photomask or irradiating a semiconductor laser beam or the like. be able to.

  By using such a method, in the present invention, the organic semiconductor material and the electrode material can be arranged with high positional accuracy on the substrate on which the self-assembled monolayer is formed.

  Hereinafter, a process of forming an organic semiconductor layer and an electrode on a substrate on which a self-assembled monomolecular film (SAM film) is formed will be described.

  In FIGS. 1 (1) to 1 (7), as an example, a silicon oxide layer is formed on a polyethersulfone resin film (200 μm) that has been subjected to corona discharge treatment, silicon oxide film or the like by CVD. A method for forming an organic semiconductor layer pattern on a substrate using the substrate 1 will be described.

  First, a surface treatment with the surface treatment material according to the present invention is performed on the entire surface of the silicon oxide layer of the substrate 1 to form a self-assembled monomolecular film (SAM film) 2 on the surface (FIG. 1 (1)). . Next, a novolak resin layer containing, for example, a photoacid generator (for example, the exemplified compound (23)) is coated on the surface to provide the photosensitive layer 3 (FIG. 1 (2)).

  Thereafter, the semiconductor channel forming region is exposed by mask exposure or laser exposure (FIG. 1 (3)). In the exposure region 3 ′ of the photosensitive layer, acid is released from the photoacid generator and supplied to the SAM film 2, and the decomposable group in the surface treatment material forming the SAM film is decomposed by the acid in the corresponding region, and is terminated. It becomes a hydroxy group and the hydrophilic region 2 ′ is formed. For example, by dissolving and removing the photosensitive layer together with the binder, only the exposed region becomes the hydrophilic region 2 'and the substrate surface is exposed (FIG. 1 (4)). Since the surface energy of the hydrophilic region 2 ′ is different from the surrounding region, the surface energy increases. Therefore, when an organic semiconductor solution such as a toluene solution is supplied to the periphery including the hydrophilic region, for example, by an inkjet method, the surface energy changes. The organic semiconductor solution gathers in the hydrophilic region (FIGS. 1 (5) to (6)), and after drying, the organic semiconductor layer 4 is formed only in the hydrophilic region on the self-assembled monolayer (FIG. 1 (7)). ). As a result, an organic semiconductor thin film having high carrier mobility can be formed with high accuracy and good reproducibility.

  Although the acid may be supplied by a printing method such as IJ, it is desirable to use an impregnated layer in order to cope with positional accuracy and liquid repellency.

  An example of an organic thin film transistor formed by the method of the present invention is shown in FIG.

  The gate electrode G and the gate insulating layer I are formed on the substrate 1, the organic semiconductor layer 4 is formed on the gate insulating layer G using the above process, and then the source electrode S and the drain electrode D are formed by patterning, for example, After forming a resist by photolithography, gold is evaporated through a mask, thereby forming a source electrode S and a drain electrode D, and the thin film transistor shown in FIG. 2A is formed. Reference numeral 2 denotes a SAM film formed on the gate insulating layer I using the surface treatment material according to the present invention, and 2 'denotes a hydrophilic region decomposed by an acid.

  The method using the surface treatment material according to the present invention can also be applied to the formation of wiring circuits such as electrodes or bus lines. For example, conductive materials such as metal nanoparticles, metal powder pastes, or dispersions in electrode materials described later can be used. In the case of using a solution process such as a conductive polymer solution, for example, if an electrode material solution or dispersion is applied to the hydrophilic region in the SAM film formed according to FIG. .

  For example, FIG. 2B shows an example of a thin film transistor in which the source electrode and the drain electrode are formed by the method using the SAM film of the present invention, and the substrate 1 has a silicon oxide layer as the gate electrode G and the gate insulating layer I. Using the substrate, the source electrode S, the drain electrode D, the wiring circuit, and the like are formed on the substrate using the metal nanoparticles by the inkjet method. Further, a top contact type organic thin film transistor is formed by forming the organic semiconductor layer 4 in the semiconductor channel region between the source electrode S and the drain electrode D, for example, by vapor deposition or by forming an organic semiconductor material solution by a solution process such as a printing method. The

  It is preferable that the contact angle (20 ° C.) of water on the substrate surface before decomposition with the acid surface-treated with the surface treatment material according to the present invention is 70 degrees or more. It is preferable that the contact angle of toluene in this region is larger than the contact angle of toluene in the region decomposed by the acid in order to enable highly accurate patterning. Further, in the organic thin film transistor, higher field effect mobility is obtained. It is preferable in obtaining.

  Although there are influences such as the surface roughness of the substrate, the contact angle of toluene in the region subjected to decomposition is 3 to 20 degrees, more preferably 5 to 15 degrees. The contact angle (20 ° C.) of toluene on the substrate surface before decomposition is preferably 15 to 100 degrees, and more preferably 20 to 90 degrees.

  As the surface treatment method using a silane coupling agent, a known method as disclosed in JP-A Nos. 2004-327857, 2005-32774, and 2005-158765 is applied. can do. For example, vapor phase methods such as CVD (Chemical Vapor Deposition) method, liquid phase methods such as spin coating method and dip coating method, and further printing methods such as screen printing method, micromold method, micro contact method, ink jet method, etc. Etc. can be applied.

  Among them, the method preferably used in the present invention is preferably a wet method in which a substrate is immersed in a solution of a surface treatment agent or a solution of a surface treatment agent is applied to a substrate and dried.

(Wet method)
In the wet method, for example, the substrate is dipped in a 1% by weight toluene solution of a surface treatment agent for 10 minutes and then dried, or this solution is applied onto the substrate and dried.

(Plasma CVD method, atmospheric pressure plasma CVD method)
A thermal CVD method in which a reactive gas containing a surface treatment agent (also referred to as a raw material for a thin film forming material in the plasma CVD method) is supplied onto a substrate heated in a range of 50 ° C. to 500 ° C., and a thin film is formed by a thermal reaction; A general plasma CVD method performed under a reduced pressure of 0.01 Pa to 100 Pa using the aforementioned atmospheric pressure plasma method apparatus, discharge gas, and reactive gas may be used. The atmospheric pressure plasma method is preferable from the viewpoints of performance, thin film formation speed, and efficient production in a non-vacuum system.

  Next, details of each component of the thin film transistor according to the present invention will be sequentially described.

<Organic semiconductor layer>
The organic semiconductor layer according to the present invention will be described.

(Organic semiconductor materials)
The organic semiconductor material according to the present invention constituting the organic semiconductor channel may be any organic compound as long as it functions as a semiconductor. Examples of organic semiconductor materials include acenes such as pentacene and tetracene disclosed in JP-A-5-55568, phthalocyanines including lead phthalocyanine disclosed in JP-A-4-167561, and the like. Disclosure in porphyrins such as benzoporphyrin disclosed in Kaikai 2004-319982 and other low molecular weight compounds such as perylene, its tetracarboxylic acid derivatives, and tetrathiafulvalene, and in JP-A-8-264805 Aromatic oligomers typically represented by thiophene hexamers called α-thienyl or sexithiophene, and conjugated polymers such as polythiophene, polythienylene vinylene and poly-p-phenylene vinylene (many of these are “advanced” ·material (Advanced Material) Journal 2002, are described in No. 2 page 99) it is generally known. Among these, when a low molecular weight compound is used as the organic semiconductor material, the effect of the present invention is more exhibited. In particular, when a low molecular weight organic semiconductor material having a weight average molecular weight of 5000 or less is used, the organic thin film transistor is driven with high mobility. It is more preferable in obtaining.

  Among the organic semiconductor materials described above, examples of low molecular weight compounds include condensed polycyclic compounds represented by pyrene, coronene, obalen and the like, derivatives thereof, anthracene, pentacene and the like and derivatives thereof (acenes), rubrene and the derivatives thereof, and the like. Preferred examples include condensed polycyclic aromatic compounds containing a hetero atom typified by hydrocarbons, benzodithiophene, anthradithiophene and the like and derivatives thereof, and thiophene oligomers. Examples of pentacenes include substituents described in International Publication No. 03/16599, International Publication No. 03/28125, US Pat. No. 6,690,029, Japanese Patent Application Laid-Open No. 2004-107216, and the like. A pentacene derivative described in U.S. Patent Application Publication No. 2003/136964 and the like; Amer. Chem. Soc. , Vol127. Examples include acenes and derivatives thereof described in No. 14.4986 and the like.

  Among these, J. et al. Amer. Chem. Soc. , Vol127. Condensed polycyclic aromatic compounds having an ethynyl substituent as described in No. 14.4986 and the like are preferably used.

  Examples of these include the following organic semiconductor compounds, but the present invention is not limited thereto.

  In the present invention, for example, a material having a functional group such as acrylic acid, acetamide, dimethylamino group, cyano group, carboxyl group, nitro group, benzoquinone derivative, Materials such as tetracyanoethylene and tetracyanoquinodimethane and their derivatives that accept electrons and functional groups such as amino groups, triphenyl groups, alkyl groups, hydroxyl groups, alkoxy groups, and phenyl groups A donor having an electron donor such as a substituted amine such as phenylenediamine, anthracene, benzoanthracene, substituted benzoanthracene, pyrene, substituted pyrene, carbazole and derivatives thereof, tetrathiafulvalene and derivatives thereof, and the like So-called doping treatment It may be subjected to.

  The doping means introducing an electron-donating molecule (acceptor) or an electron-donating molecule (donor) into the thin film as a dopant. Accordingly, the doped thin film is a thin film containing the condensed polycyclic aromatic compound and the dopant. A well-known thing can be employ | adopted as a dopant used for this invention.

<< Molecular weight of organic semiconductor materials (also called organic semiconductor molecules) >>
As the organic semiconductor material according to the present invention, any organic compound may be selected as long as it functions as a semiconductor, but a molecular weight of 100 to 5000 is preferable.

  Here, the molecular weight is measured using a mass spectrometer known to those skilled in the art. The molecular weight of a compound (oligomer, polymer, etc.) showing a molecular weight distribution (in this application, the molecular weight of the oligomer or polymer is the weight average molecular weight). Mw is used), and the molecular weight distribution is measured using a commercially available GPC (gel permeation chromatograph) method or the like.

(Measurement of weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn))
The molecular weight of the organic semiconductor material according to the present invention is preferably in the range of 100 to 5000 as described above. Furthermore, when the organic semiconductor material has a molecular weight distribution (Mw / Mn) such as an oligomer or a polymer, the ratio (molecular weight distribution) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) is: It is preferable that it is 3 or less.

  The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the organic semiconductor material according to the present invention are measured by GPC (gel permeation chromatography) using THF (tetrahydrofuran) as a column solvent. Can do.

  The measurement of the weight average molecular weight (Mw) of the organic semiconductor material according to the present invention will be described.

  Specifically, 1 ml of THF (using a degassed sample) is added to 1 mg of a measurement sample, and the sample is stirred using a magnetic stirrer at room temperature to be sufficiently dissolved. Subsequently, after processing with a membrane filter having a pore size of 0.45 μm to 0.50 μm, it is injected into a GPC (gel permeation chromatograph) apparatus.

  GPC measurement conditions are measured by stabilizing the column at 40 ° C., flowing THF (tetrahydrofuran) at a flow rate of 1 ml / min, and injecting about 100 μl of a sample having a concentration of 1 mg / ml.

  As the column, it is preferable to use a combination of commercially available polystyrene gel columns. For example, Shodex GPC KF-801, 802, 803, 804, 805, 806, 807 manufactured by Showa Denko KK, TSKgel G1000H, G2000H, G3000H, G4000H, G5000H, G6000H, G7000H, TSK guard, etc. manufactured by Tosoh Corporation A combination of these is preferred.

  As the detector, a refractive index detector (RI detector) or a UV detector is preferably used. In the measurement of the molecular weight of a sample, the molecular weight distribution of the sample is calculated using a calibration curve created using monodisperse polystyrene standard particles. About 10 points are preferably used as polystyrene for preparing a calibration curve.

  In the present invention, the molecular weight was measured under the following measurement conditions.

(Measurement condition)
Equipment: Tosoh High Speed GPC Equipment HLC-8220GPC
Column: TOSOH TSKgel Super HM-M
Detector: RI and / or UV
Eluent flow rate: 0.6 ml / min Sample concentration: 0.1% by mass
Sample volume: 100 μl
Calibration curve: prepared with standard polystyrene: standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) Mw = 100000 to 500-500 calibration curves (also referred to as calibration curves) were used to calculate the molecular weight. . It is preferable that the 13 samples are substantially equally spaced.

<Method for forming organic semiconductor layer>
A method for forming an organic semiconductor layer according to the present invention will be described.

  The organic semiconductor layer can be formed by a known method, for example, vacuum deposition, MBE (Molecular Beam Epitaxy), ion cluster beam method, low energy ion beam method, ion plating method, sputtering method. , CVD, laser deposition, electron beam deposition, electrodeposition, spin coating, dip coating, bar coating method, die coating method, spray coating method, LB method, etc., and screen printing, inkjet printing, blade coating, etc. Can do.

  Among these, it is preferable to form the organic semiconductor layer by coating from the viewpoint of productivity. As the coating method, a spin coating method, a blade coating method, a dip coating method, a roll coating method, a bar coating method, a die coating method, an ink jet printing, or the like that can easily and precisely form a thin film using an organic semiconductor solution is preferred. .

In addition, as described in Advanced Material 1999 No. 6, pages 480 to 483, those in which a precursor such as pentacene is soluble in a solvent is obtained by heat-treating the precursor film formed by coating. A thin film of material may be formed.
(Organic solvent used for coating)
The organic solvent used in preparing the organic semiconductor droplet is preferably an aromatic hydrocarbon, an aromatic halogenated hydrocarbon, an aliphatic hydrocarbon or an aliphatic halogenated hydrocarbon, and the aromatic hydrocarbon or aromatic halogen More preferred are hydrocarbons or aliphatic hydrocarbons.

  Examples of the aromatic hydrocarbon organic solvent include toluene, xylene, mesitylene, and methylnaphthalene, but the present invention is not limited thereto.

  Examples of the organic solvent for the aromatic halogenated hydrocarbon include chlorobenzene, bromobenzene, iodobenzene, o-dichlorobenzene, m-dichlorobenzene, o-dibromobenzene, m-dibromobenzene, o-diiodobenzene, m- Diiodobenzene, chlorotoluene, bromotoluene, iodotoluene, dichlorotoluene, dibromotoluene, difluorotoluene, chloroxylene, bromoxylene, iodoxylene, chloroethylbenzene, bromoethylbenzene, iodoethylbenzene, dichloroethylbenzene, dibromoethylbenzene, chlorocyclopentadiene, Although chlorocyclopentadiene etc. can be mentioned, this invention is not limited to these.

  Examples of the aliphatic hydrocarbon organic solvent include octane, 4-methylheptane, 2-methylheptane, 3-methylheptane, 2,2-dimethylhexane, 2,3-dimethylhexane, 2,4-dimethylhexane, 2,5-dimethylhexane, 3,3-dimethylhexane, 3,4-dimethylhexane, 3-ethylhexane, 2,2,3-trimethylpentane, 2,2,4-trimethylpentane, 2,3,3- Trimethylpentane, 2,3,4-trimethylpentane, 2-methyl-3-ethylpentane, 3-methyl-3-ethylpentane, decane, 2,2,3,3-tetramethylhexane, 2,2,5, 5-tetramethylhexane, 3,3,5-trimethylheptane, nonane, 2,2,5-trimethylhexane, 4-ethylheptane, 2,3-di Tilheptane, 2-methyloctane, dodecane, hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, heptane, 2-methylhexane, 3-methylhexane, 2,2 -Chain aliphatic hydrocarbons such as dimethylpentane, 2,3-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethylpentane, 3-ethylpentane, 2,2,3-trimethylbutane, cyclohexane, cyclo Examples include cycloaliphatic hydrocarbons such as pentane, methylcyclohexane, methylcyclopentane, p-menthane, decalin, and cyclohexylbenzene, but the present invention is not limited thereto. The aliphatic hydrocarbon used in the present invention is preferably a cyclic aliphatic hydrocarbon.

  Examples of the organic solvent for the aliphatic halogenated hydrocarbon include chloroform, bromoform, dichloromethane, dichloroethane, trichloroethane, difluoroethane, fluorochloroethane, chloropropane, dichloropropane, chloropentane, and chlorohexane. It is not limited to these.

  These organic solvents used in the present invention may be used alone or in combination of two or more. The organic solvent preferably has a boiling point of 50 ° C to 250 ° C.

(Thickness of organic semiconductor layer)
The film thickness of these organic semiconductor layers is not particularly limited, but the characteristics of the obtained transistor are often greatly influenced by the film thickness of the organic semiconductor layer, and the film thickness varies depending on the organic semiconductor, but is generally 1 μm. Hereinafter, 10 to 300 nm is particularly preferable.

《Insulating layer》
Various insulating films can be used as the insulating layer of the gate electrode of the organic thin film transistor of the present invention, and an inorganic oxide film having a high relative dielectric constant is particularly preferable. Inorganic oxides include silicon oxide, aluminum oxide, tantalum oxide, titanium oxide, tin oxide, vanadium oxide, barium strontium titanate, barium zirconate titanate, lead zirconate titanate, lead lanthanum titanate, strontium titanate, Examples thereof include barium titanate, barium magnesium fluoride, bismuth titanate, strontium bismuth titanate, strontium bismuth tantalate, bismuth tantalate niobate, and trioxide yttrium. Of these, silicon oxide, aluminum oxide, tantalum oxide, and titanium oxide are preferable. Inorganic nitrides such as silicon nitride and aluminum nitride can also be suitably used.

  Examples of the method for forming the film include a vacuum process, a molecular beam epitaxial growth method, an ion cluster beam method, a low energy ion beam method, an ion plating method, a CVD method, a sputtering method, an atmospheric pressure plasma method and the like, spraying Examples include a wet process such as a coating method, a spin coating method, a blade coating method, a dip coating method, a casting method, a roll coating method, a bar coating method, a coating method such as a die coating method, and a patterning method such as printing or inkjet. Can be used depending on the material.

  The wet process is a method of applying and drying a liquid in which fine particles of inorganic oxide are dispersed in an arbitrary organic solvent or water using a dispersion aid such as a surfactant as required, or an oxide precursor, for example, A so-called sol-gel method in which an alkoxide solution is applied and dried is used.

  Among these, the atmospheric pressure plasma CVD method described above is preferable.

  It is also preferable that the insulating layer is composed of an anodized film or the anodized film and an insulating film. The anodized film is preferably sealed. The anodized film is formed by anodizing a metal that can be anodized by a known method.

Examples of the metal that can be anodized include aluminum and tantalum, and the anodizing method is not particularly limited, and a known method can be used. An oxide film is formed by anodizing. Any electrolyte solution that can form a porous oxide film can be used as an anodizing treatment. Generally, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, boric acid, sulfamic acid, benzenesulfonic acid are used. Or a mixed acid or a salt thereof in which two or more of these are combined. The treatment conditions for anodization vary depending on the electrolyte used, and thus cannot be specified in general. In general, the concentration of the electrolyte is 1 to 80% by mass, the temperature of the electrolyte is 5 to 70 ° C., and the current density is 0. Suitable ranges are 5 to 60 A / dm ² , voltage 1 to 100 volts, and electrolysis time 10 seconds to 5 minutes. A preferred anodizing treatment is a method in which an aqueous solution of sulfuric acid, phosphoric acid or boric acid is used as an electrolytic solution and the treatment is performed with a direct current, but an alternating current can also be used. The concentration of these acids is preferably 5 to 45% by mass, and the electrolytic treatment is preferably performed for ²⁰ to 250 seconds at an electrolyte temperature of 20 to 50 ° C. and a current density of 0.5 to 20 A / dm ² .

  In addition, as an organic compound film, polyimide, polyamide, polyester, polyacrylate, photo radical polymerization type, photo cation polymerization type photo curable resin, or a copolymer containing an acrylonitrile component, polyvinyl phenol, polyvinyl alcohol, novolac resin, Also, cyanoethyl pullulan or the like can be used.

  As the method for forming the organic compound film, the wet process is preferable.

  An inorganic oxide film and an organic oxide film can be laminated and used together. The thickness of these insulating films is generally 50 nm to 3 μm, preferably 100 nm to 1 μm.

  When these organic and inorganic coatings are subjected to a surface treatment with the surface treatment agent, the coating surface is also capable of reacting with a group such as alkoxysilane or halogenosilane in a silane coupling agent, such as a hydroxyl group or an amino group. It is preferable to have this reactive group.

  The same applies to the support and substrate described later. For example, in the case of a silicon substrate, a thermal oxide film is formed on the surface, or the surface does not have a reactive group for the silane coupling agent. A material layer having a hydroxy group such as a silicon oxide layer is preferably formed on the substrate.

<Support>
Various materials can be used as the base material constituting the support, for example, glass, quartz, aluminum oxide, sapphire, silicon nitride, silicon carbide and other ceramic bases, silicon, germanium, gallium arsenide, gallium phosphide. Further, a semiconductor substrate such as gallium nitrogen, paper, nonwoven fabric, or the like can be used.

  Especially, it is preferable that the board | substrate which concerns on this invention consists of resin, for example, a plastic film sheet can be used. Examples of the plastic film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), Examples include films made of cellulose triacetate (TAC), cellulose acetate propionate (CAP), and the like.

  By using a plastic film, the weight can be reduced as compared with the case of using a glass substrate, and the portability can be improved and the resistance to impact can be improved.

<Electrode material>
In the organic thin film transistor of the present invention, the electrode material for forming the source electrode or the drain electrode is not particularly limited as long as it is a conductive material, and is formed of a known electrode material.

  The electrode material is not particularly limited as long as it is a conductive material. Platinum, gold, silver, nickel, chromium, copper, iron, tin, antimony lead, tantalum, indium, palladium, tellurium, rhenium, iridium, aluminum, ruthenium, Germanium, molybdenum, tungsten, tin oxide / antimony, indium tin oxide (ITO), fluorine-doped zinc oxide, zinc, carbon, graphite, glassy carbon, silver paste and carbon paste, lithium, beryllium, sodium, magnesium, potassium, calcium , Scandium, titanium, manganese, zirconium, gallium, niobium, sodium, sodium-potassium alloy, magnesium, lithium, aluminum, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum Miniumu mixture, a magnesium / indium mixture, aluminum / aluminum oxide mixture, a lithium / aluminum mixture, or the like is used.

  In addition, known conductive polymers whose conductivity is improved by doping or the like, for example, conductive polyaniline, conductive polypyrrole, conductive polythiophene (polyethylenedioxythiophene and polystyrenesulfonic acid complex, etc.) are also preferably used.

  As the material for forming the source electrode or the drain electrode, among the materials listed above, those having low electric resistance at the contact surface with the semiconductor layer are preferable. In the case of a p-type semiconductor, platinum, gold, silver, ITO, conductive polymer are particularly preferable. And carbon are preferred.

  When the source electrode or the drain electrode is used, the electrode is formed using a fluid electrode material such as a solution, paste, ink, or dispersion containing the above-described conductive material, particularly a conductive polymer, or platinum, gold, silver, A fluid electrode material containing metal fine particles containing copper is preferable because an electrode pattern can be formed by coating or printing.

  In addition, the solvent or dispersion medium is preferably a solvent or dispersion medium containing 60% or more, preferably 90% or more of water in order to suppress damage to the organic semiconductor.

  As the fluid electrode material containing metal fine particles, for example, a known conductive paste or the like may be used. Preferably, metal fine particles having a particle diameter of 1 nm to 50 nm, preferably 1 nm to 10 nm are dispersed as required. A material dispersed in a dispersion medium that is water or any organic solvent using a stabilizer.

  Materials for metal fine particles include platinum, gold, silver, nickel, chromium, copper, iron, tin, antimony lead, tantalum, indium, palladium, tellurium, rhenium, iridium, aluminum, ruthenium, germanium, molybdenum, tungsten, zinc, etc. Can be used.

  As a method for producing such a dispersion of fine metal particles, metal ions are reduced in a liquid phase, such as a physical generation method such as gas evaporation method, sputtering method, metal vapor synthesis method, colloid method, coprecipitation method, etc. Examples of the chemical production method for producing metal fine particles include those described in JP-A-11-76800, JP-A-11-80647, JP-A-11-319538, JP-A-2000-239853, and the like. In the gas described in JP-A-2001-254185, 2001-53028, 2001-35255, 2000-124157, 2000-123634, etc. It is a dispersion of fine metal particles produced by an evaporation method.

  After forming an electrode using these metal fine particle dispersions and drying the solvent, the metal fine particles are obtained by heating in a shape within a range of 100 to 300 ° C., preferably 150 to 200 ° C. as necessary. An electrode pattern having a target shape is formed by heat fusion.

  As a method for forming a conductive pattern such as an electrode or wiring, the conductive thin film can be formed by using a method such as vapor deposition or sputtering using the above as a raw material. An electrode may be formed by using a known photolithography method or a lift-off method, and there is a method in which a resist is formed and etched on a metal foil such as aluminum or copper by thermal transfer or ink jet. Alternatively, a conductive polymer solution or dispersion, a dispersion containing metal fine particles, or the like may be directly patterned by an ink jet method, or may be formed from a coating film by lithography, laser ablation, or the like.

  Furthermore, a method of patterning a conductive ink or conductive paste containing a conductive polymer or metal fine particles by a printing method such as relief printing, intaglio printing, lithographic printing, or screen printing can also be used.

  Moreover, the electrode formation method by the electroless plating method is to contact the plating agent after arranging a catalyst that acts on the plating agent to cause electroless plating in the portion where the electrode is provided.

  As a result, the catalyst and the plating agent come into contact with each other, and electroless plating is applied to the portion to form an electrode. A method using electroless plating for electrode formation can form a low-resistance electrode easily and at low cost without complicated steps.

  The conductive patterns such as electrodes and wiring according to the present invention are preferably formed by a solution process using a fluid material.

《Protective layer》
It is also possible to provide a protective layer on the organic thin film transistor of the present invention. Examples of the protective layer include the inorganic oxides and inorganic nitrides described above, and the protective layer is preferably formed by the atmospheric pressure plasma method. This improves the durability of the organic thin film transistor.

<< Manufacture of organic thin-film transistor elements >>
The organic thin film transistor has a source electrode and a drain electrode connected by an organic semiconductor layer on a substrate, a top gate type having a gate electrode on an insulating layer thereon, and a gate electrode on a substrate first, It is roughly classified into a bottom gate type having a source electrode and a drain electrode connected by an organic semiconductor film through an insulating layer. The organic thin film transistor of the present invention may be either a top gate type or a bottom gate type.

  The organic thin film transistor (TFT) of the present invention may be a thin film transistor element sheet in which a plurality of organic thin film transistors are arranged.

  The thin film transistor element sheet has a large number of organic thin film transistors arranged in a matrix. A gate bus line of a gate electrode of each organic thin film transistor, a source bus line connected to a source electrode of each organic thin film transistor, and the like. A drain electrode of each organic thin film transistor is connected to an output element such as a liquid crystal or an electrophoretic element. Constitutes the pixel. In addition, a vertical drive circuit and a horizontal drive circuit are arranged for driving this. The method according to the present invention can be used for producing a thin film transistor element sheet.

  When the support is a plastic film, the organic thin film transistor of the present invention preferably has at least one of an undercoat layer containing a compound selected from inorganic oxides and inorganic nitrides, and an undercoat layer containing a polymer.

  Examples of the inorganic oxide contained in the undercoat layer include silicon oxide, aluminum oxide, tantalum oxide, titanium oxide, tin oxide, vanadium oxide, barium strontium titanate, barium zirconate titanate, lead zirconate titanate, titanate Examples include lead lanthanum, strontium titanate, barium titanate, barium magnesium fluoride, bismuth titanate, strontium bismuth titanate, strontium bismuth tantalate, bismuth tantalate niobate, and yttrium trioxide. Examples of the inorganic nitride include silicon nitride and aluminum nitride.

  Of these, silicon oxide, aluminum oxide, tantalum oxide, titanium oxide, and silicon nitride are preferable.

  In the present invention, the undercoat layer containing a compound selected from inorganic oxides and inorganic nitrides is preferably formed by the atmospheric pressure plasma method described above.

  Polymers used for the undercoat layer containing polymer include polyester resin, polycarbonate resin, cellulose resin, acrylic resin, polyurethane resin, polyethylene resin, polypropylene resin, polystyrene resin, phenoxy resin, norbornene resin, epoxy resin, vinyl chloride-vinyl acetate Copolymer, vinyl chloride resin, vinyl acetate resin, copolymer of vinyl acetate and vinyl alcohol, partially hydrolyzed vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer Polymer, ethylene-vinyl alcohol copolymer, polyvinyl alcohol, chlorinated polyvinyl chloride, ethylene-vinyl chloride copolymer, vinyl polymers such as ethylene-vinyl acetate copolymer, polyamide resin, ethylene-butadiene resin, Tajien - rubber-based resin such as acrylonitrile resin, silicone resin, and fluorine resins.

(Preferred embodiment)
Hereinafter, the present invention will be specifically described with reference to preferred embodiments of the present invention. The present invention is not limited to these.

(Embodiment 1)
A preferred embodiment and each step in the production of an organic thin film transistor (TFT) using the surface treatment material according to the present invention will be described.

  FIG. 3 is a schematic cross-sectional view showing each step of TFT fabrication for forming an organic semiconductor layer using a SAM film.

First, a resin support; a polyethersulfone resin film (200 μm) was used as the substrate 1, and a corona discharge treatment was first performed on the substrate 1 under the condition of 50 W / m ² / min. Thereafter, an undercoat layer was formed in order to improve adhesion as follows.

(Formation of undercoat layer)
A coating solution having the following composition was applied to a dry film thickness of 2 μm, dried at 90 ° C. for 5 minutes, and then cured for 4 seconds from a distance of 10 cm under a 60 W / cm high-pressure mercury lamp.

Dipentaerythritol hexaacrylate monomer 60g
Dipentaerythritol hexaacrylate dimer 20g
Dipentaerythritol hexaacrylate trimer or higher component 20g
Diethoxybenzophenone UV initiator 2g
Silicone surfactant 1g
75g of methyl ethyl ketone
Methyl propylene glycol 75g
Furthermore, a silicon oxide film having a thickness of 50 nm was formed on the layer by continuous atmospheric pressure plasma treatment under the following conditions, and these layers were used as the undercoat layer 1a (FIG. 3 (1)). As the atmospheric pressure plasma processing apparatus, an apparatus according to FIG. 6 described in JP-A No. 2003-303520 was used.

(Used gas)
Inert gas: helium 98.25% by volume
Reactive gas: oxygen gas 1.5 volume%
Reactive gas: Tetraethoxysilane vapor (bubbled with helium gas) 0.25% by volume
(Discharge conditions)
Discharge output: 10 W / cm ²
(Electrode condition)
Here, discharge was performed at a frequency of 13.56 MHz using a high-frequency power source manufactured by Pearl Industries.

  The electrode is coated with 1 mm of alumina by ceramic spraying on a stainless steel jacket roll base material having cooling means with cooling water, and then a solution obtained by diluting tetramethoxysilane with ethyl acetate is applied and dried, and then sealed by ultraviolet irradiation. This is a roll electrode having a dielectric (relative dielectric constant of 10) having a pore surface, smoothed surface and having a maximum surface roughness (Rmax) defined by JIS B 0601 of 5 μm (relative dielectric constant 10). On the other hand, as the application electrode, a hollow rectangular stainless steel pipe was coated with the same dielectric as described above under the same conditions.

<Formation of gate bus line and gate electrode>
Next, a gate bus line and a gate electrode G are formed.

That is, after the photosensitive resin composition liquid 1 having the following composition is applied on the undercoat layer 1a and dried at 100 ° C. for 1 minute, a photosensitive resin layer having a thickness of 2 μm is formed. The pattern of the gate bus line and the gate electrode was exposed with a semiconductor laser having an oscillation wavelength of 830 nm and an output of 100 mW at an energy density of 200 mJ / cm ² and developed with an alkaline aqueous solution to obtain a resist image. Furthermore, after forming an aluminum film having a thickness of 300 nm on the entire surface by sputtering, the remaining part of the photosensitive resin layer is removed by MEK, thereby producing the gate bus line and the gate electrode G. (FIG. 3 (2)).

(Photosensitive resin composition liquid 1)
Dye A 7 parts novolak resin (novolak resin co-condensed with phenol and m-, p-mixed cresol and formaldehyde (Mw = 4000, molar ratio of phenol / m-cresol / p-cresol is 5/57/38, respectively)) 90 parts Crystal violet 3 parts Propylene glycol monomethyl ether 1000 parts

  In addition, the pattern of the gate bus line and the gate electrode is formed by the electroless plating method by using the method of the present invention based on the combination of the electrostatic suction type inkjet apparatus and the electroless plating method, not the patterning by resist formation using the photosensitive resin. It may be formed.

  Next, an anodic oxide film was formed on the gate electrode as an auxiliary insulating film for smoothing and improving the insulating properties by the following anodic oxide film forming step (not shown in the figure).

(Anodized film forming process)
After forming the gate electrode, the substrate is washed thoroughly, and the thickness of the anodic oxide film reaches 120 nm using a direct current supplied from a low-voltage power supply of 30 V in a 10 mass% ammonium phosphate aqueous solution for 2 minutes. Anodized. After thoroughly washing, steam sealing treatment was performed in a saturated steam chamber at 1 atm and 100 ° C. In this way, a gate electrode having an anodized film was produced on a polyether sulfone resin film subjected to a subbing treatment.

  Next, at a film temperature of 200 ° C., a silicon oxide layer having a thickness of 30 nm was provided using the gas used in the atmospheric pressure plasma method described above, and the gate insulating layer I was formed by combining the anodic oxide film (alumina film). (3) in FIG.

(Used gas)
Inert gas: helium 98.25% by volume
Reactive gas: oxygen gas 1.5 volume%
Reactive gas: Tetraethoxysilane vapor (bubbled with helium gas) 0.25% by volume
(Discharge conditions)
Discharge output: 10 W / cm ²
Next, the substrate provided with the gate insulating layer in a 1% by mass toluene solution of the surface treatment material (Exemplified Compound 2) was immersed for 10 minutes, and then pulled up and dried (50 ° C.) for 30 minutes. Next, the substrate was washed with toluene and further dried. As a result, the hydroxyl group on the surface of the gate insulating layer I and the surface treatment material reacted to form a bond, and the SAM film 2 was formed on the entire surface of the gate insulating layer I (FIG. 3 (4)).

Next, the following photosensitive layer coating solution was applied at 100 ° C. using a spin coater so that the film thickness after drying was 1.5 g / m ² and dried for 10 minutes to form photosensitive layer 3 (FIG. 3). (5)).

(Photosensitive layer coating solution)
Binder B 60 parts Photoacid generator A (2-trichloromethyl-5- [β- (2-benzofuryl) vinyl] -1,3,4-oxadiazole) 5 parts Infrared absorber IR18 2 parts propylene glycol monomethyl ether 1000 parts Nonionic activator (polyethylene glycol molecular weight 2000) 0.5 parts Binder B is a co-condensation compound of phenol, m-, p-mixed cresol and formaldehyde (Mn = 500, Mw = 2500, phenol: m- It is a novolak resin in which the molar ratio of cresol: p-cresol is 20:48:32)

Next, the surface of the photosensitive layer was exposed with a semiconductor laser (wavelength 830 nm, output 500 mW). The laser beam diameter was 13 μm at 1 / e ² of the intensity at the peak. The resolution was 2000 DPI in both the scanning direction and the sub-scanning direction (1 inch = number of dots per 2.5 cm), and the semiconductor channel region on the substrate was exposed (FIG. 3 (6)). Acid was generated in the light irradiation region 3 ′ of the photosensitive layer, and a hydrophilic region 2 ′ was formed in the corresponding region on the SAM film 2.

  Next, the photosensitive layer was removed by washing with propylene glycol monomethyl ether to expose the SAM film on the gate insulating layer (FIG. 7).

  In the light irradiation region, a hydrophilic region was formed by decomposition by the acid generated by the SAM film.

  Next, an organic semiconductor layer was formed on the surface-treated gate insulating layer using the organic semiconductor 1 as a semiconductor material. That is, a toluene solution (0.5% by mass) of the organic semiconductor 1 is prepared and ejected to a substantial region where a channel is to be formed by using a piezo ink jet method (FIG. 3 (8)). And dried at 50 ° C. for 3 minutes. According to drying, that is, evaporation of the solvent, droplets gather in the second region, and the organic semiconductor layer 4 having a film thickness of 20 nm is formed only in the second region in contact with the first region on the substrate (FIG. 3). (9)).

  Next, the source electrode S and the drain electrode D were formed by vapor-depositing gold through a mask, and the thin film transistor shown in FIG. 3 (10) was formed.

  As described above, the preferred embodiments of the method for manufacturing the organic semiconductor element and the TFT sheet of the present invention have been shown. Thus, according to the present invention, the organic semiconductor thin film having high orientation can be stably stabilized at a predetermined position on the substrate. Therefore, it is possible to obtain an organic thin film transistor and a TFT sheet having high carrier mobility.

(Embodiment 2)
Next, an example of manufacturing an electrode using a SAM film according to the present invention which is a preferred embodiment will be described.

  A gate electrode, a gate insulating layer, and a SAM film were prepared in the same manner as in Embodiment 1, and a photosensitive layer was formed in the same manner (FIG. 3 (5)).

  Next, using the same semiconductor laser, the source electrode, the drain electrode, and the source bus line region on the substrate were exposed in a pattern.

  A hydrophilic region 2 ′ is formed in the SAM film 2 by the acid generated in the exposed region (FIG. 4 (1)).

  After exposure, the photosensitive layer was removed with propylene glycol monomethyl ether for 5 minutes, and the electrode formation region in the SAM film 2 on the gate insulating layer was hydrophilized (FIG. 4 (2)).

  Next, gold nanoparticle ink was deposited on the source electrode and drain electrode regions by an inkjet method, and then dried by heating at 100 ° C. for 10 minutes (FIGS. 4 (3) to (4)). With drying, the gold nanoparticle ink gathered in the hydrophilized region, and the source electrode S and drain electrode D were formed on the hydrophilized region with high positional accuracy (thickness 100 nm).

  A pentacene vapor-deposited film (thickness 25 nm) was further formed from above using a vacuum vapor deposition machine to form an organic semiconductor layer (FIG. 4 (5)). A bottom gate bottom contact type thin film transistor was formed.

(Evaluation of organic thin film transistor)
With respect to the organic thin film transistors fabricated in Embodiments 1 and 2, the carrier mobility was obtained from the saturation region of the IV characteristics. As a result, the mobility was 0.4 cm ² / Vs or more, and the p-channel enhancement type FET was operated well. did.

  Also, it was found that the position accuracy is good and the reproducibility of the characteristics is good also in the coating formation of the organic semiconductor thin film and the electrode.

  In the method according to the present invention, a self-assembled monomolecular film (SAM film) is arranged on the surface of a substrate, and surface energy is changed by acid generated in a pattern, thereby reproducibility and reproduction of electrodes or semiconductor channels. In addition, in the formation of the organic semiconductor layer, a semiconductor layer with higher orientation and higher mobility can be formed using a self-assembled monolayer.

It is a figure explaining the process of forming an organic-semiconductor material layer on the board | substrate with which the SAM film was formed. It is a figure which shows the example of the organic thin-film transistor formed by the method of this invention. It is a schematic sectional drawing which shows each process of TFT preparation which forms an organic-semiconductor layer using a SAM film. It is a schematic sectional drawing of each process of TFT preparation which manufactures an electrode using a SAM film.

Explanation of symbols

1 Substrate 2 Self-assembled monolayer (SAM film)
3 Photosensitive layer 4 Organic semiconductor layer G Gate electrode I Gate insulating layer S Source electrode D Drain electrode

Claims (8)

A surface treatment material having a protecting group in the molecule that decomposes in the presence of an acid. A substrate comprising a surface to which the surface treatment material according to claim 1 is bonded or bonded, and a film for supplying an acid to the surface. The substrate according to claim 2, wherein the acid supplying film generates an acid by the action of light or heat. 4. The substrate according to claim 3, wherein the acid supplying film contains a photoacid generator. The substrate according to claim 4, wherein the acid supplying film contains a dye having a function of spectrally sensitizing the photoacid generator. A thin film transistor, wherein the surface treatment material according to claim 1 is bonded or bonded to a surface of a gate insulating film. The film for supplying acid in the substrate according to claim 3 is subjected to image-wise light or heat to generate an image-like acid, and then the film for supplying acid is removed. A method for treating a substrate surface, which is characterized. A method for manufacturing a semiconductor device, wherein a pattern of a semiconductor film or an electrode is formed in a region where an acid is formed imagewise using the substrate surface processing method according to claim 7.

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