JP2003309266A - Method for manufacturing organic thin-film transistor element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an organic thin-film transistor element wherein a leakage current is reduced, and the missing of pixels is few. <P>SOLUTION: In the method for manufacturing the organic thin-film transistor element wherein at least a gate electrode, an insulating layer, a source electrode, a drain electrode and an organic semiconductor layer are installed on a retaining member, after a process is performed wherein the surface of a region which is in contact with the organic semiconductor layer is subjected to plasma treatment previously, a process for arranging the organic semiconductor layer is included. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing an organic thin film transistor element.

[0002]

2. Description of the Related Art With the spread of information terminals, there is an increasing need for FPDs (flat panel displays) as displays for computers. In addition, with the progress of computerization, the opportunity to electronically provide information that was conventionally provided in paper medium is increased, and as a thin, light, and easily portable mobile display medium, electronic paper or The need for digital paper is also increasing.

Generally, in a flat panel display device, a display medium is formed by using elements utilizing liquid crystal, organic EL, electrophoresis or the like. Further, in such a display medium, a technique using an active driving element has become mainstream in order to secure the uniformity of screen brightness and the screen rewriting speed. For example, in a normal computer display, these TFTs (Thin Film Tr
A liquid crystal, organic EL, etc. are sealed.

On the other hand, recently, thin film transistors (TFTs)
Organic materials are being considered for use as active semiconductor layers within. Organic materials are easy to process and generally TF
Since it has a high affinity with the plastic substrate on which T is formed,
It is expected to utilize the active semiconductor layer and sh tie in a thin film device.

Therefore, studies are underway as a low-cost, large-area device, particularly as an active driving element for a display, and techniques such as Japanese Patent Laid-Open Nos. 10-190001 and 2000-307172 are disclosed.

In order for an organic semiconductor to be used as an active semiconductor layer in a thin film TFT, the on / off ratio, leakage current and gate drive voltage of the resulting device must be sufficiently satisfied. .

However, in recent years, the organic semiconductors that have been reported to be successful as TFTs are mainly of the intrinsic type, and the organic semiconductor forming the channel is required to have a very high purity. Even if the material of the organic semiconductor has high purity, there is a problem that the leakage current becomes large due to the inclusion of impurities in the vicinity of the channel during element formation. Further, in the manufacturing process of the TFT sheet, there is a problem that minute dust (particles) adheres to the TFT, which easily causes pixel defects of the display.

There is a demand for improvement in these problems.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to reduce the leak current and prevent pixel defects by preventing impurities from mixing in the vicinity of the channel and adhesion of fine dust (particles) during element formation. It is an object of the present invention to provide a method for manufacturing an organic thin film transistor element with less power consumption.

[0010]

The above objects of the present invention have been achieved by the following constitutions 1 and 2.

1. At least a gate electrode on the support,
In a method for manufacturing an organic thin film transistor element having an insulating layer, a source electrode, a drain electrode, and an organic semiconductor layer, a step of providing the organic semiconductor layer after the step of plasma-treating a surface of a portion in contact with the organic semiconductor layer in advance A method for manufacturing an organic thin film transistor element, comprising:

2. 2. The method for manufacturing an organic thin film transistor element described in 1 above, wherein the plasma treatment is an atmospheric pressure plasma treatment method.

The present invention will be described in detail below. The present inventors have made various studies on the problems described above, and as a result, claim 1
At least a gate electrode on the support,
In a method of manufacturing an organic thin film transistor element having a gate insulating layer, a source electrode, a drain electrode, and an organic semiconductor layer, a step of making a profit of the organic semiconductor layer is provided after a step of plasma-treating a surface of a portion in contact with the organic semiconductor layer in advance. As a result, the inventors have found a method for manufacturing an organic thin film transistor element in which the leak current is reduced and the number of pixel defects is small by preventing the mixing of impurities near the channel and the adhesion of minute dust (particles) at the time of element formation.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

The structure of the organic thin film transistor element according to the present invention will be described with reference to FIGS. 1 (a), 1 (b) and 1 (c).

FIG. 1A is a schematic view showing an example of a top gate type organic thin film transistor element.

In FIG. 1A, the top gate type organic thin film transistor element according to the present invention has a source electrode 2, a drain electrode 3 and the source electrode 2 on a support 7.
And an organic semiconductor layer 4 connecting the drain electrode 3 with the source electrode 2, the drain electrode 3, and the organic semiconductor layer 4.
The insulating layer 6 is provided so as to cover the whole of the above, and the gate electrode 5 is further provided on the insulating layer 6.

FIGS. 1B and 1C are schematic views showing an example of a bottom gate type organic thin film transistor element.

In FIG. 1B, in the bottom gate type organic thin film transistor element according to the present invention, the gate electrode 5 is provided on the support 7, and the insulating layer 6 is formed so as to cover the entire gate electrode 5. A source electrode 2 and a drain electrode 3 are provided on the insulating layer 6, and an organic semiconductor layer 4 is further provided so as to connect the source electrode 2 and the drain electrode 3.

In FIG. 1C, in the bottom gate type organic thin film transistor element according to the present invention, a gate electrode is provided on a support 7, and an insulating layer 6 is formed so as to cover the entire gate electrode 5, and then the gate electrode 5. After disposing the organic semiconductor layer 4 on the insulating layer 6, the source electrode 2 and the drain electrode 3 are provided.

1 (a) to 1 (c), each material constituting the organic transistor element 1 according to the present invention will be described.

<< Organic Semiconductor Layer >> The organic semiconductor layer according to the present invention has a function of connecting a source electrode and a drain electrode in an organic semiconductor element, but as an organic semiconductor material forming the organic semiconductor layer, a π-conjugated system is used. Materials are preferably used.

Examples of the π-conjugated material include polypyrroles such as polypyrrole, poly (N-substituted pyrrole), poly (3-substituted pyrrole), poly (3,4-disubstituted pyrrole), polythiophene and poly (3). -Substituted thiophene), poly (3,4-disubstituted thiophene), polythiophenes such as polybenzothiophene, polyisothianaphthenes such as polyisothianaphthene, polythienylenevinylenes such as polythienylenevinylene, poly ( poly (p-phenylene vinylene) such as p-phenylene vinylene), polyaniline, poly (N-substituted aniline), poly (3-substituted aniline), polyaniline such as poly (2,3-substituted aniline), polyacetylene, etc. Polyacetylenes, polydiacetylenes and other polydiacetylenes, polyazulenes , Polypyrenes such as polypyrene, polycarbazoles such as polycarbazole and poly (N-substituted carbazole), polyselenophenes such as polyselenophene, polyfurans such as polyfuran and polybenzofuran, and poly (p-phenylene) ) Etc., polyindoles such as polyindole, polypyridazines such as polypyridazine, naphthacene, pentacene, hexacene, heptacene, dibenzopentacene, tetrabenzopentacene, pyrene, dibenzopyrene, chrysene, perylene. , Coronene, terylene, ovalene, quaterrylene, circumanthracene, and other polyacenes, and derivatives of polyacene in which some of the carbon atoms are replaced with atoms such as N, S, O, and functional groups such as carbonyl groups (triphenodiene). Oxazine,
Polymers such as triphenodithiazine, hexacene-6,15-quinone), polyvinylcarbazole, polyphenylene sulfide, and polyvinylene sulfide, and polycyclic condensates described in JP-A No. 11-195790 can be used. . In addition, α-, which is, for example, a thiophene hexamer having the same repeating unit as those polymers,
Oligomers such as sexithiophene, α, ω-dihexyl-α-sexithiophene, α, ω-dihexyl-α-kinkethiophene, α, ω-bis (3-butoxypropyl) -α-sexithiophene, and styrylbenzene derivatives are also suitable. Can be used for. Further, metal phthalocyanines such as copper phthalocyanine and fluorine-substituted copper phthalocyanine described in JP-A No. 11-251601, naphthalene 1,4,5,8-tetracarboxylic acid diimide, N,
N'-bis (4-trifluoromethylbenzyl) naphthalene-1,4,5,8-tetracarboxylic acid diimide together with N, N'-bis (1H, 1H-perfluorooctyl), N, N'-bis ( 1H, 1H-perfluorobutyl) and N, N′-dioctylnaphthalene-1,4
Naphthalenetetracarboxylic acid diimides such as 5,8-tetracarboxylic acid diimide derivative and naphthalene-2,3,6,7-tetracarboxylic acid diimide, and anthracene-2,3,6,7-tetracarboxylic acid diimide Condensed ring tetracarboxylic acid diimides such as anthracene tetracarboxylic acid diimides, C ₆₀ , C ₇₀ , C ₇₆ , C
_Examples include fullerenes such as ₇₈ and C ₈₄ , carbon nanotubes such as SWNT, and dyes such as merocyanine dyes and hemicyanine dyes.

Among these π-conjugated materials, thiophene, vinylene, thienylenevinylene, phenylenevinylene, p-phenylene, their substitution products or two or more of these repeating units are used as repeating units, and the number of repeating units is n. Is 4 to 10 or the number of repeating units n
Is preferably 20 or more, at least one selected from the group consisting of condensed polycyclic aromatic compounds such as pentacene, fullerenes, condensed ring tetracarboxylic acid diimides, and metal phthalocyanines.

As other organic semiconductor materials,
Tetrathiafulvalene (TTF) -Tetracyanoquinodimethane (TCNQ) complex, Bisethylenetetrathiafulvalene (BEDTTTF) -Perchloric acid complex, BEDTT
Organic molecular complexes such as TF-iodine complex and TCNQ-iodine complex can also be used. Further, σ-conjugated polymers such as polysilane and polygermane, and JP-A-2000-2
The organic / inorganic hybrid material described in 60999 can also be used.

In the present invention, a material having a functional group such as acrylic acid, acetamide, dimethylamino group, cyano group, carboxyl group or nitro group in the organic semiconductor layer, benzoquinone derivative, tetracyanoethylene and tetracyano Materials such as quinodimethane and their derivatives that serve as acceptors for accepting electrons, materials having functional groups such as amino groups, triphenyl groups, alkyl groups, hydroxyl groups, alkoxy groups, phenyl groups, and phenylenediamine Substituted amines such as, anthracene, benzoanthracene, substituted benzanthracenes, pyrene, substituted pyrene, carbazole and its derivatives, tetrathiafulvalene and its derivatives, etc. Let
A so-called doping process may be performed.

The doping is an electron-accepting molecule (activator).
Dopant with scepter) or electron donating molecule (donor)
Means to be introduced into the thin film of the organic semiconductor layer as
It Therefore, the doped thin film is
It is a thin film containing a polycyclic aromatic compound and a dopant.
Acceptor and donor as dopants used in the present invention
Any of these can be used. C as this acceptor
l₂, Br₂, I₂, ICl, ICl₃, IBr, IF, etc.
Halogen, PF_Five, AsF_Five, SbF_Five, BF₃, BCl
₃, BBr₃, SO₃Lewis acids such as HF, HC1, H
NO₃, H₂SO_Four, HClO_Four, FSO₃H, ClSO
₃H, CF₃SO₃Proton acids such as H, acetic acid, formic acid,
Organic acids such as mino acids, FeCl₃, FeOCl, TiC
l_Four, ZrCl _Four, HfCl_Four, NbF_Five, NbCl_Five, T
aCl_Five, MoCl_Five, WF_Five, WCl₆, UF₆, LnC
l₃(Ln = La, Ce, Nd, Pr, etc.
And transition metal compounds such as Y), Cl^-, Br^-,
I^-, ClO_Four ^-, PF₆ ^-, AsF_Five ^-, SbF₆ ^-, B
F_Four ^-, Electrolyte anions such as sulfonate anions
Can be mentioned. Further, as a donor, Li, N
Alkali metals such as a, K, Rb, Cs, Ca, Sr,
Alkaline earth metals such as Ba, Y, La, Ce, Pr,
Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Y
rare earth metal such as b, ammonium ion, R_FourP⁺, R
_FourAs⁺, R₃S⁺, Acetylcholine, etc.
Wear. As a method of doping these dopants,
Thin film of organic semiconductor for
Introducing method, Dopant during thin film formation of organic semiconductor
Any of the methods of introduction can be used. With the former method
And vapor phase doping using a gaseous dopant,
A solution or liquid dopant is brought into contact with the thin film to
Liquid phase doping, solid state dopant
A solid material for diffusively doping a dopant by contacting the thin film.
The method of phase doping can be mentioned. Liquid phase
Doping by applying electrolysis
The efficiency of can be adjusted. The latter method is organic
Use the same mixed solution or dispersion of semiconductor material and dopant.
It may be applied and dried at times. For example, using the vacuum deposition method
Co-evaporate dopant with organic semiconductor material
By doing so, the dopant can be introduced. Also
When forming a thin film by the sputtering method, an organic semiconductor material
Sputtering using a dual target of dopant and dopant
The dopant can be introduced into the thin film.
Still other methods include electrochemical doping, photoinitiation
Chemical doping such as doping and publications for example
(Industrial Materials, Vol. 34, No. 4, p. 55, 1986)
Use any of the physical doping techniques shown, such as ion implantation.
It can be used.

(Method for Producing Organic Semiconductor Layer) As a method for producing a thin film of these organic semiconductors, vacuum vapor deposition method, molecular beam epitaxial growth method, ion cluster beam method, low energy ion beam method, ion plating method, CV
D method, sputtering method, plasma polymerization method, electrolytic polymerization method, chemical polymerization method, spray coating method, spin coating method,
Blade coating method, dip coating method, casting method, roll coating method, bar coating method, die coating method and LB
Method, etc., and can be used depending on the material. However, among these, from the viewpoint of productivity, spin coating, blade coating, dip coating, roll coating, bar coating, die coating, etc. can be used to easily and precisely form a thin film using a solution of an organic semiconductor material. Is preferred.

(Film Thickness of Organic Semiconductor Layer) The film thickness of the thin film made of these organic semiconductors is not particularly limited, but the characteristics of the obtained transistor are greatly influenced by the film thickness of the active layer made of the organic semiconductor. In many cases, the film thickness varies depending on the organic semiconductor, but is preferably 1 μm or less, particularly preferably in the range of 10 nm to 300 nm.

<< Gate Electrode, Source Electrode, Drain Electrode >> The gate electrode, source electrode, and drain electrode according to the present invention will be described.

The source electrode, drain electrode and gate electrode are not particularly limited as long as they are conductive materials, and platinum, gold,
Silver, nickel, chromium, copper, iron, tin, antimony lead, tantalum, indium, palladium, tellurium, rhenium,
Iridium, aluminum, ruthenium, germanium, molybdenum, tungsten, tin antimony oxide, 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 mixture, magnesium / indium. Mixture, aluminum / aluminum oxide mixture,
A lithium / aluminum mixture or the like is used, but in particular platinum, gold, silver, copper, aluminum, indium, I
TO and carbon are preferred.

Further, a known conductive polymer whose conductivity is improved by doping or the like, such as conductive polyaniline, conductive polypyrrole, conductive polythiophene, or a complex of polyethylenedioxythiophene and polystyrenesulfonic acid, is also preferably used.

Among the source electrodes and the drain electrodes according to the present invention, those having a small electric resistance at the contact surface with the semiconductor layer are preferable among the above.

(Method for forming electrode) As a method for forming an electrode, a conductive thin film formed by using the above-mentioned conductive material as a raw material by a method such as vapor deposition or sputtering is subjected to a known photolithography method or lift-off method. There are a method of forming an electrode by using it, a method of thermal transfer on a metal foil such as aluminum or copper, and a method of etching using a resist such as an inkjet.

The conductive polymer solution or dispersion or the conductive fine particle dispersion may be directly patterned by ink jet, or may be formed from a coating film by lithography or laser ablation. Further, a method of patterning an ink containing a conductive polymer or conductive fine particles, a conductive paste or the like by a printing method such as letterpress, intaglio, planographic printing or screen printing can also be used.

The conductive fine particles have a particle size of 1 n.
m-50 nm, preferably 1 nm-10 nm platinum, gold,
Silver, nickel, chromium, copper, iron, tin, tantalum, indium, cobalt, palladium, tellurium, rhenium, iridium, aluminum, ruthenium, germanium, molybdenum, tungsten, zinc, etc. can be used, but particularly preferably, Examples thereof include fine metal particles having a work function of 4.5 eV or more, such as platinum, gold, silver, copper, cobalt, chromium, iridium, nickel, palladium, molybdenum, and tungsten.

As a method for producing such a metal fine particle dispersion, a physical production method such as an in-gas evaporation method, a sputtering method, a metal vapor synthesis method, a colloid method, a coprecipitation method or the like can be used.
A chemical production method of producing metal fine particles by reducing metal ions in a liquid phase can be mentioned, and preferably, JP-A No. 11-7.
No. 6800, No. 11-80647, No. 319538, the colloid method shown in JP-A-2000-239853, JP-A-2001-254185, and JP-A-2001-5302.
8, JP 2001-35814A, JP 2001-352A
55, JP 2000-124157, JP 2000-1.
It is a dispersion produced by the gas evaporation method described in 23634. After coating these dispersions and molding them into an electrode pattern, the solvent is dried and the temperature is raised to 100 ° C.
The electrode can be formed by heat-sealing the metal fine particles by heat treatment in the range of 300 to 300 ° C., preferably 150 to 200 ° C.

(Production of Source Electrode and Drain Electrode) Production of the source electrode and the drain electrode according to the present invention will be described with reference to FIGS. Steps (1) to (3) of FIG. 2 and FIG.
As shown in steps (c) to (e), the gaps formed by cutting the electrode film are connected by the organic semiconductor layer to form the source electrode and the drain electrode.

Here, as a method of cutting the electrode film,
Examples thereof include laser ablation method, dicing saw, diamond blade, and diamond needle processing.

As a laser for cutting, a ruby laser, a glass laser, a YAG laser, GaAlAs or In
Semiconductor laser such as GaAsP, ArF, KrF, XeC
1, excimer laser such as XeF, carbon dioxide laser, Ar
Examples thereof include ion lasers, and among them, excimer lasers are preferable, and KrF excimer lasers are particularly preferably used.

For example, the ablation method using an excimer laser can form holes and grooves free from thermal distortion and burrs and having micron order accuracy in a short time at room temperature and atmospheric pressure. Further, by irradiating the work (work) with the excimer laser light through the mask, the mask pattern can be transferred to form holes or grooves of any shape. The excimer laser is oscillated as a pulse, and the material can be removed by about 0.01 μm to 0.5 μm in one pulse, so that the depth of removal can be accurately controlled by the number of pulses.

<< Insulating Layer >> The insulating layer according to the present invention will be described.

Although various insulating films can be used as the insulating layer, an inorganic oxide film having a high relative dielectric constant is particularly preferable. As the inorganic oxide, 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 yttrium trioxide.
Of these, preferred are silicon oxide, aluminum oxide, tantalum oxide, and titanium oxide. Silicon nitride,
Inorganic nitrides such as aluminum nitride can also be preferably used.

(Method for forming insulating layer) As the method for forming the above film, a vacuum vapor deposition method, a molecular beam epitaxial growth method,
Dry process such as ion cluster beam method, low energy ion beam method, ion plating method, CVD method, sputtering method, atmospheric pressure plasma method, spray coating method, spin coating method, blade coating method, dip coating method, casting method A wet process such as a coating method such as a roll coating method, a bar coating method, a die coating method, a patterning method such as printing or inkjet, and the like can be used depending on the material.

The wet process is carried out by coating and drying a liquid in which fine particles of an inorganic oxide are dispersed in an arbitrary organic solvent or water using a dispersion auxiliary agent such as a surfactant, if necessary, or an oxide precursor. A so-called sol-gel method is used in which a solution of a body, for example, an alkoxide body is applied and dried.

Among the methods for forming the film described above, the atmospheric pressure plasma method and the sol-gel method are preferable.

The method of forming the insulating film by the plasma film forming process under the atmospheric pressure will be described below. That is, the plasma film forming process under the atmospheric pressure refers to a process of discharging under the atmospheric pressure or a pressure in the vicinity of the atmospheric pressure, plasma-exciting the reactive gas, and forming a thin film on the substrate. For details, see JP-A-11-133205 and JP-A-200
0-185362, JP-A-11-61406, JP-A-2
000-147209 and 2000-121804 (hereinafter, also referred to as atmospheric pressure plasma method).
By the plasma film forming process under atmospheric pressure, a highly functional thin film can be formed with high productivity.

As the organic compound film, polyimide, polyamide, polyester, polyacrylate, photoradical polymerization type, photocationic polymerization type photocurable resin, or copolymer containing an acrylonitrile component, polyvinylphenol, polyvinyl alcohol. , Novolak resins, phosphazene compounds including cyanoethyl pullulan, polymers and elastomers can also be used.

The above-mentioned wet process is preferable as the method for forming the organic compound film. The inorganic oxide film and the organic oxide film can be laminated and used together.

(Thickness of Insulating Layer) As the thickness of the insulating film,
The range of 50 nm to 3 μm is preferable, and more preferably,
It is 100 nm to 1 μm.

(Support) The support according to the present invention will be described.

As the support, it is preferable to use a polymer film, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether sulfone (PES), polyether imide,
Examples thereof include films made of polyether ether ketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC), cellulose acetate propionate (CAP) and the like.

A plasticizer such as trioctyl phosphate or dibutyl phthalate may be added to these polymer films, or a known ultraviolet absorber such as benzotriazole or benzophenone may be added. In addition, a resin produced by applying a so-called organic-inorganic polymer hybrid method, in which a raw material of an inorganic polymer such as tetraethoxysilane is added, and a high molecular weight is obtained by applying energy such as a chemical catalyst, heat, or light. It can also be used as a raw material.

<< Method of Manufacturing Organic Thin Film Transistor Element >>
2, a method for manufacturing an organic thin film transistor element of the present invention,
This will be described with reference to FIG.

FIG. 2 is a view for explaining the manufacturing process of the top gate type organic thin film transistor element shown in FIG. 1 (a).

In FIG. 2, the organic thin film transistor element is manufactured by the following steps (1) to (5).

Step (1): The electrode film 8 is formed on the support 7. The electrode film 8 may be formed by a photolithography method, vapor deposition, or sputtering, or may be formed by patterning a paste of an electrode material, or may be formed by attaching a metal foil or the like.

Step (2): Next, the electrode film 8 formed is
For example, a source electrode 2 and a drain electrode 3 are formed by cutting using a KrF excimer laser or a dicing saw, and then plasma treatment, which will be described later, is performed to exist in the vicinity of the surface of the support 7 and the cut electrode film. Removes minute dust (particles) and impurities.

Step (3): The organic semiconductor layer 4 is formed by using a photolithography method, an ink jet method or the like.

Step (4): The insulating layer 6 is formed by the plasma film forming process described above. However, the plasma film forming process used in the step (4) is a step of forming the insulating layer 6 by using a material such as an inorganic oxide as a reactive gas in a plasma state, and is the same as that used in the step (2). This is a process different from the plasma process for removing dust (particles) and impurities.

Step (5): The gate electrode 5 is formed on the insulating layer 6 in the same manner as the formation of the electrode film 8 to form a top gate type organic thin film transistor element.

FIG. 3 is a diagram for explaining a manufacturing process of the bottom gate type organic thin film transistor element shown in FIG. 1 (b).

In FIG. 3, the organic thin film transistor element is manufactured by the following steps (a) to (e).

Step (a): The gate electrode 5 is provided on the support 7 in the same manner as in the step (1) described above.

Step (b): The gate electrode 5 is formed on the insulating layer 6
Coating treatment is performed. Here, for forming the insulating layer 6, the plasma film forming process or the like described in the step (4) can be similarly applied.

Step (c): The electrode film 8 is formed on the insulating layer 6 in the same manner as in the step (1) described above.

Step (d): In the same manner as in the above-mentioned step (2), the electrode film 8 is cut, and then plasma treatment is performed to remove dust on the insulating layer 6, the source electrode 2 and the drain electrode 3 near the surface thereof. (Particles) and impurities are removed.

Step (e): The organic semiconductor layer 4 is formed between the source electrode 2 and the drain electrode 3 to form a bottom gate type organic thin film transistor element.

<< Plasma Treatment Step: Also referred to as Etching Treatment Step >> The portions in contact with the organic semiconductor layer 4 shown in the step (2) of FIG. 2 and the step (d) of FIG. 3 (for example, the support 7 and the source electrode). (2, drain electrode 3, insulating layer 6, etc.) is subjected to a plasma treatment in advance to remove dust (particles) and impurities, an inert gas or a reactive gas in a plasma discharge state is used to remove the above-mentioned components. Etching processing (specifically, removal of dust and impurities) is performed.

Here, examples of the inert gas used in the plasma discharge state used for the etching treatment include rare gases such as helium and argon, and examples of the reactive gas used in the plasma discharge state include tetrafluoromethane and oxygen. Etc. are preferably used, and among them, oxygen is preferably used.

Here, when oxygen is used for etching treatment (including use of oxygen alone to use of mixture of oxygen and other inert gas), it is also called oxygen plasma treatment method.

In the etching process, it is preferable to select an appropriate mixing ratio of the above-mentioned inert gas or reactive gas according to the degree of the etching process.

The atmospheric pressure plasma processing method according to the present invention is
The above-mentioned discharge plasma treatment is performed at or near atmospheric pressure. Here, near atmospheric pressure means 20 k.
It represents a pressure of Pa to 110 kPa, but in order to obtain the effect described in the present invention preferably, it is 93 kPa to 104 kPa.
Is preferred.

<< Plasma Discharge Treatment Device >> A plasma discharge treatment device used for plasma discharge treatment will be described with reference to FIGS.

The plasma discharge processing apparatus used in the present invention comprises a plasma discharge processing container as shown in FIG. 4 which will be described later, and a roll electrode which is a ground electrode and a fixed application electrode which is arranged at a position opposed to the roll electrode. Discharged between the electrodes, between the electrodes, introduced an inert gas or a reactive gas into a plasma state, wound on the roll electrode,
By exposing the substrate material for organic thin film transistor element production (in the present application, the configuration of the element before the organic semiconductor layer 4 is arranged) to an inert gas or a reactive gas in a plasma state, the substrate material is formed on the substrate material. The organic semiconductor layer is formed.

FIG. 4 is a schematic view showing an example of a plasma discharge processing container provided in the plasma discharge processing apparatus.

In FIG. 4, the substrate material for producing the organic thin film transistor element is transported while being wound around the roll electrode 25 which rotates in the transport direction (clockwise in the figure). The fixed electrode 26 is composed of a plurality of cylinders and is installed so as to face the roll electrode 25. The substrate material wound around the roll electrode 25 is pressed by the nip rollers 65 and 66, is regulated by the guide roller 64, is transported to the discharge processing space secured by the plasma discharge processing container 31, is subjected to discharge plasma processing, and is then subjected to discharge plasma processing. , Guide roller 67
It is conveyed to the next process via. Further, the partition plate 54 is disposed in the vicinity of the nip rollers 65 and 66, and has a function of adjusting entry of air entrained in the substrate material into the plasma discharge processing container 31.

The inert gas or instinct gas in the plasma discharge state used for the discharge plasma treatment is the gas supply port 5.
2 is introduced into the plasma discharge treatment container 31 and the treated gas is exhausted from the exhaust port 53.

As a power source for applying a voltage to the applying electrode,
High frequency power supply (200k
Hz), a high frequency power supply manufactured by Pearl Industry (800 kHz), a high frequency power supply manufactured by JEOL Ltd. (13.56 MHz), a high frequency power supply manufactured by Pearl Industry (150 MHz) and the like can be used.

FIG. 5 is a conceptual diagram showing an example of the plasma discharge processing apparatus. 5, the part of the plasma discharge processing container 31 is the same as that described in FIG. 4, but a gas generator 51, a power supply 41, an electrode cooling unit 60 and the like are further arranged as a device configuration. As the coolant for the electrode cooling unit 60, an insulating material such as distilled water or oil is preferably used. The electrodes 25 and 36 shown in FIG. 5 preferably have a gap between opposing electrodes set to, for example, about 1 mm.

The distance between the electrodes is determined in consideration of the thickness of the solid dielectric material provided on the base material of the electrodes, the magnitude of the applied voltage, the purpose of utilizing plasma, and the like. The shortest distance between the solid dielectric and the electrode when the solid dielectric is installed on one of the electrodes, and the distance between the solid dielectrics when the solid dielectric is installed on both of the electrodes are uniform in all cases. From the viewpoint of discharging, it is preferably 0.5 mm to 20 mm, and particularly preferably 1 mm ± 0.5 mm.

The roll electrode 25 and the fixed electrode 36 are arranged at predetermined positions in the plasma discharge processing container 31, the flow rate of the mixed gas generated by the gas generator 51 is controlled, and the plasma is supplied from the air supply port 52. It is placed in an electric discharge processing container 31, the inside of the plasma electric discharge processing container 31 is filled with an inert gas or a reactive gas used for plasma processing, and an exhaust port 53 is provided.
Exhaust more. Next, a voltage is applied to the electrode 36 by the power source 41, the roll electrode 25 is grounded to the ground, and discharge plasma is generated. Here, a substrate material F for producing an organic thin film transistor element is supplied from a roll-shaped original winding base material 61,
Through the guide roller 64, the plasma discharge treatment container 31
The inner electrode is conveyed in a single-sided contact state (in contact with the roll electrode 25), the surface of the substrate material F for producing the organic thin film transistor element is subjected to plasma discharge treatment by discharge plasma, and then the guide roller It is conveyed to the next process via 67.

The value of the voltage applied to the electrode 36 fixed by the power supply 41 is appropriately determined. For example, the voltage is about 0.5 kV to 10 kV and the power supply frequency is 100 kH.
It is preferable that the frequency is adjusted to z and 150 MHz or less. Regarding the method of applying a power supply, either a continuous sine wave continuous oscillation mode called a continuous mode or an intermittent oscillation mode called ON / OFF which is intermittently called a pulse mode may be adopted.

As the plasma discharge treatment container 31, a treatment container made of Pyrex (R) glass is preferably used.
It is also possible to use metal as long as it can be insulated from the electrodes. For example, a polyimide resin or the like may be attached to the inner surface of an aluminum or stainless steel frame, and the metal frame may be sprayed with ceramics to have an insulating property.

Further, in order to minimize the influence on the substrate material for producing the organic thin film transistor element during the discharge plasma treatment, the temperature of the substrate material for producing the organic thin film transistor element during the discharge plasma treatment is kept at room temperature (15 ° C.). ~ 25
C.) to less than 200.degree. C.,
More preferably, the temperature is adjusted to room temperature to 100 ° C.
In order to adjust to the above temperature range, the electrode and the base material are subjected to discharge plasma treatment while being cooled by a cooling means, if necessary.

Further, in the discharge electrode, the maximum height (Rmax) of the surface roughness defined by JIS B 0601 at least on the side of the electrode which is in contact with the substrate material for producing the organic thin film transistor element is 10 μm or less. From the viewpoint of obtaining the effects described in the present invention, it is more preferable that the maximum value of the surface roughness is 8 μm.
It is below, and particularly preferably, it is adjusted to 7 μm or less.

The center line average surface roughness (Ra) defined by JIS B 0601 is preferably 0.5 μm or less, more preferably 0.1 μm or less.

[0088]

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

Example 1 << Preparation of Organic Thin-Film Transistor Element 1 >> A top-gate organic thin-film transistor element 1 having a structure as shown in FIG. 1A was prepared as follows.

150 μm thick polyimide film (PI
20 nm gold thin film was vapor-deposited on the (film), and the source and drain electrodes were formed by the photolithography method. The channel length was 5 μm.

Here, using a plasma discharge treatment container as shown in FIG. 4 and a plasma discharge treatment apparatus as shown in FIG. 5 on the surface portion of the polyimide film on which the source electrode, the drain electrode and the organic semiconductor layer are provided, Atmospheric pressure plasma treatment (oxygen gas introduction) was performed.

(Plasma processing apparatus and plasma processing conditions) A plasma discharge processing container as shown in FIG. 4 was placed in the plasma discharge processing apparatus shown in FIG. A thin film semiconductor device 1 was manufactured.

Here, the power source used for plasma generation is a high frequency power source (50 kHz) manufactured by Shinko Electric Co., Ltd., an impulse high frequency power source (100 kH used in continuous mode) manufactured by HEIDEN LABORATORY
z), high frequency power source manufactured by Pearl Industry (200 kHz), high frequency power source manufactured by Pearl Industry (800 kHz), high frequency power source manufactured by JEOL Ltd. (13.56 MHz), high frequency power source manufactured by Pearl Industry (150 MHz) and the like can be preferably used.

<< Discharge Condition >> The discharge output was adjusted to 4 W / cm ² .

<< Etching Gas Composition >> The composition of the reactive gas used for the plasma treatment is described below.

Inert gas: Argon 98.75% by volume Reactive gas 1: Oxygen gas (1 with respect to the whole etching gas)
Further, a chloroform solution of poly (3-hexylthiophene) was discharged using a piezo system inkjet nozzle to fill the space between the source and drain electrodes. After removing the solvent chloroform by drying, it was heat-treated at 100 ° C. for 1 minute. At this time, the thickness of the poly (3-hexylthiophene) film was about 100 nm. After being exposed to the atmosphere of ammonia gas at room temperature for 5 hours, the source electrode,
Drain electrode and poly (3-hexylthiophene)
A film having a thickness of 3 is formed on the film by the atmospheric pressure plasma method described above.
A silicon oxide film having a thickness of 00 nm was formed.

Adhesiveness to the poly (3-hexylthiophene) film was good, and a dense film was obtained.

Then, using a commercially available silver paste, the width is 10 μm.
m gate electrodes were formed to obtain the organic thin film transistor element 1 shown in the structural example (a) as shown in FIG.

<< Preparation of Organic Thin Film Transistor Element 2 >>:
Comparative Example In the production of the organic thin film transistor element 1, the source,
An organic thin film transistor element 2 was produced in the same manner except that the atmospheric pressure plasma treatment described above was not performed on the polyimide surface of the drain and channel portions.

Obtained organic thin film transistor elements 1 and 2
For each of the above, the transistor characteristics were evaluated as described below.

<< Evaluation of Transistor Characteristics >> Using organic thin film transistor elements 1 and 2, wirings as shown in FIG. 6 were respectively attached, and transistor characteristics were evaluated.

(Evaluation of Leakage Current) The leak current I _off (nA) was measured for each of 100 organic thin film transistor elements 1 and 2 when the applied voltage between the source electrode and the drain electrode was −30V. The leak current value (nA) shown below is an average value of 100 pieces.

(Yield Evaluation) With respect to each of 100 organic thin film transistor elements 1 and 100 organic thin film transistor elements 2, the transistor operation was examined by a method known to those skilled in the art, and those not operating were counted to evaluate the yield.

The results obtained are shown below.   Organic thin film transistor element Leakage current (nA) Yield   1 (invention) 0.1 0   2 (Comparison) 5.0 20

[0105]

EFFECTS OF THE INVENTION According to the present invention, by preventing impurities from being mixed in the vicinity of a channel and adhesion of fine dust (particles) at the time of forming an element, a leakage current is reduced and an organic thin film transistor element with few pixel defects is formed. It was possible to provide a manufacturing method.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of the configuration of an organic transistor element of the present invention.

FIG. 2 is a conceptual diagram showing a manufacturing process of the transistor element having the configuration of FIG.

FIG. 3 is a conceptual diagram showing a manufacturing process of the transistor element having the configuration of FIG. 1 (b).

FIG. 4 is a schematic view showing an example of a plasma discharge processing container.

FIG. 5 is a conceptual diagram showing an example of a plasma discharge processing apparatus.

FIG. 6 is a conceptual diagram showing a circuit for evaluating the FET characteristics of a transistor element.

[Explanation of symbols]

1 Organic transistor element 2 Source electrode 3 drain electrode 4 channels 5 Gate electrode 6 insulating layers 7 Support

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4M104 AA09 AA10 BB02 BB04 BB05                       BB06 BB07 BB08 BB09 BB13                       BB14 BB16 BB17 BB18 BB36                       CC01 CC05 DD31 DD34 DD37                       DD51 DD68 DD75 EE03 EE16                       EE17 EE18 FF13 GG08 GG09                 5F110 AA06 BB01 CC01 CC03 CC07                       DD01 EE01 EE02 EE03 EE04                       EE06 EE07 EE41 EE42 EE43                       EE44 FF01 FF02 FF03 FF21                       FF27 FF28 FF29 GG05 GG25                       GG28 GG32 GG41 GG42 GG43                       GG44 GG52 GG53 GG54 GG55                       GG57 HK01 HK02 HK03 HK04                       HK06 HK07 HK31 HK32 HK33                       HK42 QQ03 QQ06 QQ14

Claims (2)

[Claims] 1. In a method of manufacturing an organic thin film transistor element having at least a gate electrode, an insulating layer, a source electrode, a drain electrode, and an organic semiconductor layer on a support, the surface of a portion in contact with the organic semiconductor layer is plasma-treated in advance. After the step, there is a step of providing the organic semiconductor layer, and a method of manufacturing an organic thin film transistor element. 2. The method for manufacturing an organic thin film transistor element according to claim 1, wherein the plasma treatment is an atmospheric pressure plasma treatment method.