JP2003324202A - Organic thin-film transistor and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an organic thin-film transistor which is capable of performing highly precise patterning at a low cost without being subjected to complicated manufacturing steps, has high carrier mobility, is capable of lowering a gate voltage, has a high current value in the ON state of switching and consequently a high ON/OFF value of current, and is capable of operating at a high frequency, and to obtain a method of manufacturing the organic thin-film transistor that can suppress the characteristic degradation of the transistor caused by the manufacturing steps. <P>SOLUTION: A source electrode and a drain electrode of the organic thin-film transistor are formed at least in an insulating layer, and the thin-film transistor has a through-hole region that contacts an organic semiconductor channel. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art With the spread of information terminals, there is an increasing need for flat panel displays as displays for computers. In addition, with the progress of computerization, there is an increasing opportunity to digitize the information that was previously provided on paper media, and as a mobile display medium that is thin, light, and easily portable, electronic paper or digital The need for paper is also growing.

Generally, in a flat panel display device, a display medium is formed by using an element utilizing liquid crystal, organic EL, electrophoresis or the like. In such a display medium, a thin film transistor (TFT) is used as an image driving element in order to secure the uniformity of screen brightness and the screen rewriting speed.
A technique using an active driving element configured by is becoming mainstream.

Here, the TFT element is usually formed on a glass substrate mainly by a-Si (amorphous silicon) or p-Si.
It is manufactured by sequentially forming a semiconductor thin film such as (polysilicon) and a metal thin film such as a source, a drain and a gate electrode on a substrate. In manufacturing a flat panel display using this TFT, in addition to a vacuum system equipment such as CVD and sputtering and a thin film forming step that requires a high temperature treatment step, a highly accurate photolithography step is required, which results in a reduction in equipment cost and running cost. The load is very heavy. Further, with the recent needs for larger screens of displays, their costs have become extremely huge.

In recent years, as a technique for compensating for the disadvantages of the conventional TFT element, research and development of an organic TFT element using an organic semiconductor material have been actively pursued. Since this organic TFT element can be manufactured by a low temperature process, it is said that a light and hard-to-break resin substrate can be used, and further 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 having excellent productivity and very low cost can be realized.

An important requirement in this organic TFT technology is high-precision patterning of channels. The above-mentioned patents and Japanese Patent Laid-Open Nos. 10-190001 and 2000
In 307172 or the like, high precision photolithography is required for molding the channel portion, patterning formation is difficult, which complicates the manufacturing process, requires a large amount of equipment for the process, and increases the cost. The present invention enables high-precision patterning more easily and greatly improves these problems.

Further, as an organic thin film transistor, for example, WO 01/47043 discloses an all polymer type organic T film.
FT technology is disclosed. Although a simple process using inkjet or coating is proposed, the carrier mobility of the device is low, the gate voltage is high, and the current value in the switching ON state is low. There are problems such as low current ON / OFF value.

Further, in a step following the formation of the organic semiconductor layer, for example, a step of applying a photosensitive resin material for patterning or a developing step of the photosensitive resin layer, a coating solvent used in the step or development Due to the influence of liquid components,
There is a problem that the characteristics as a transistor deteriorate.

[0009]

It is possible to perform highly accurate patterning at low cost without complicated manufacturing steps, high carrier mobility, and low gate voltage.
An organic thin film transistor which has a high current value in a switching ON state, therefore has a high ON / OFF value of the current, and has a high driving frequency, and which can suppress deterioration of transistor characteristics in the manufacturing process. To obtain a manufacturing method of.

[0010]

The above objects of the present invention can be achieved by the following means.

1. An organic thin film transistor in which a source electrode and a drain electrode are formed in at least an insulating layer and formed from a through hole portion in contact with an organic semiconductor channel.

2. An organic semiconductor is formed on a support through a gate electrode, a gate insulating layer, an organic semiconductor layer, a second insulating layer that are sequentially provided on the gate electrode, and two through holes that penetrate the second insulating layer. An organic thin film transistor including a source electrode and a drain electrode that are respectively joined to the layers.

3. 3. The organic thin film transistor according to 2 above, wherein the second insulating layer is made of a photosensitive resin.

4. 4. The organic thin film transistor according to 2 or 3, wherein the second insulating layer is formed by aqueous coating.

5. On a support, a first electrode and a second electrode, an organic semiconductor layer provided thereon, two through holes penetrating the organic semiconductor layer, and the organic semiconductor layer and the organic semiconductor layer through the through holes. An organic thin film transistor comprising a source electrode and a drain electrode which are respectively joined to the first electrode and the second electrode, a gate insulating layer formed on the constituent, and a gate electrode formed on the gate insulating layer.

6. A first electrode and a second electrode on the support; an insulating layer formed on the first electrode and the second electrode; two through holes penetrating at least the insulating layer; and the first electrode via the through holes. An organic thin film transistor comprising a source electrode and a drain electrode joined to each of the second electrodes, an organic semiconductor layer and a gate insulating layer sequentially formed on the constituent, and a gate electrode formed on the gate insulating layer.

7. A first electrode and a second electrode on a support, an insulating layer and an organic semiconductor layer sequentially formed thereon, two through holes penetrating at least the insulating layer and the organic semiconductor layer, and the through hole A source electrode and a drain electrode which are respectively bonded to the organic semiconductor layer and the first electrode and the second electrode via the gate electrode, a gate insulating layer formed on the constituent, and a gate formed on the gate insulating layer. Organic thin film transistor consisting of electrodes.

8. A gate electrode is provided on a support, a gate insulating layer, an organic semiconductor layer, and a second insulating layer are sequentially formed on the gate electrode, and two through holes that penetrate the second insulating layer and contact the organic semiconductor layer. And a source electrode and a drain electrode are formed so as to be bonded to the organic semiconductor layer through the through hole.

9. 7. The method for manufacturing an organic thin film transistor as described in 6 above, wherein the second insulating layer is formed of a photosensitive resin.

10. 10. The method for manufacturing an organic thin film transistor described in 8 or 9, wherein the second insulating layer is formed by water-based coating.

11. A first electrode and a second electrode are provided on a support, an organic semiconductor layer is formed on the electrode, and two organic semiconductor layers that penetrate the organic semiconductor layer are in contact with the first electrode and the second electrode. After forming the through hole, a source electrode and a drain electrode are formed so as to be bonded to the organic semiconductor layer, the first electrode, and the second electrode through the through hole, and the source electrode and the drain electrode are formed. A method of manufacturing an organic thin-film transistor, comprising forming a gate insulating layer on the gate insulating layer, and further providing a gate electrode on the gate insulating layer.

12. A first electrode and a second electrode are provided on a support, an insulating layer is formed on them, and at least two insulating layers are formed to penetrate the insulating layer and contact the first electrode and the second electrode, respectively. After forming the through hole, a source electrode and a drain electrode are formed so as to be bonded to the first electrode and the second electrode through the through hole,
A method of manufacturing an organic thin film transistor, further comprising sequentially forming an organic semiconductor layer and a gate insulating layer on the source electrode and the drain electrode, and providing a gate electrode on the gate insulating layer.

13. A first electrode and a second electrode are provided on a support, an insulating layer and an organic semiconductor layer are sequentially formed on them, and the first electrode and the organic semiconductor layer penetrate at least the insulating layer and the organic semiconductor layer. After providing two through holes in contact with the second electrode, a source electrode and a drain electrode are formed so as to be bonded to the organic semiconductor layer, the first electrode, and the second electrode through the through holes. A method for manufacturing an organic thin film transistor, further comprising forming a gate insulating layer on the source electrode and the drain electrode, and providing a gate electrode on the gate insulating layer.

14. 14. The method for manufacturing an organic thin film transistor according to any one of 8 to 13 above, wherein the electrode material solution or the dispersion liquid is ejected onto the through hole portion using an inkjet to perform patterning.

The present invention will be specifically described below with reference to the following embodiments.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION An organic thin film transistor using an organic semiconductor material of the present invention as an active semiconductor layer and a method for manufacturing the same will be described below with reference to FIGS.

FIG. 1 shows a bottom gate type organic thin film transistor configuration example of the present invention and a manufacturing process thereof.

FIG. 1A shows an example of the structure of the organic thin film transistor to be manufactured. That is, the gate electrode G is attached on the support 1, and the gate insulating layer 2 is formed on the gate electrode G.
The organic semiconductor layer 3, the source electrode S and the drain electrode D provided in contact with the organic semiconductor layer, and a second insulating layer which is a protective film and also stabilizes the interface barrier between the source / drain electrode and the organic semiconductor layer. It is composed of 4.

FIG. 1B shows a state in which the gate electrode G is provided on the support. The support 1 is made of glass, as described later.
Further, for example, it may be made of a flexible resin sheet such as polyethylene terephthalate (PET).

The gate electrode, which will be described later, is platinum, gold,
The electrode is formed of a conductive material such as silver or nickel, and as a method of forming the electrode, a conductive thin film is formed using the above-mentioned raw materials by a method such as vapor deposition or sputtering, and a known photolithography method or lift-off method is used. It can be obtained by a patterning method. Further, the conductive fine particle dispersion liquid or the like may be printed / patterned by a printing method, an inkjet method or the like.

After forming the gate electrode pattern, a dielectric layer to be a gate insulating layer is applied. FIG. 1C shows a state in which the gate insulating layer 2 is formed on the support provided with the gate electrode G.

As the gate insulating layer, an inorganic oxide film having a high relative dielectric constant, particularly a film of silicon oxide, silicon nitride, aluminum oxide or the like is applied on the gate electrode pattern. As a method for forming the inorganic oxide film, a dry process called a vapor deposition method such as a vacuum vapor deposition method, a CVD method, a sputtering method, an atmospheric pressure plasma method, or the like,
Wet processes such as spin coating method using a so-called sol-gel method, blade coating method, dip coating method, die coating method and the like, printing method, patterning method such as ink jet method and the like can be mentioned. Particularly preferred is a coating method using an atmospheric pressure plasma method and a sol-gel method. The thickness of the insulating layer is preferably 10
It is 0 nm to 1 μm.

As the insulating film used for the insulating layer, polyimide, polyamide, or the like, or an organic compound film such as a photocurable resin can be used. In the case of an organic compound film, it is preferable to form it by a wet process such as coating. The inorganic oxide film and the organic oxide film can be laminated and used together.

Then, as shown in FIG. 1D, an organic semiconductor layer 3 is applied on the formed gate insulating layer 2.

As the organic semiconductor, a π-conjugated material such as polypyrrole or polythiophene is used, and a vapor deposition method such as a vacuum deposition method, a CVD method, a sputtering method, a plasma polymerization method, an electrolytic polymerization method, a chemical polymerization method, or These organic semiconductor thin films are formed by a coating method such as a spray coating method or a spin coating method or an LB method. However, among these, from the viewpoint of productivity, a coating method that can easily and precisely form a thin film using an organic semiconductor solution is preferred. The thickness of the thin film made of these organic semiconductors is not particularly limited,
The characteristics of the obtained transistor are often greatly influenced by the film thickness of the active layer made of an organic semiconductor, and the film thickness is generally 1 μm or less, particularly preferably 10 to 300 nm, though it varies depending on the organic semiconductor.

After forming the organic semiconductor thin film, a second insulating layer 4 is further provided as shown in FIG.

The second insulating layer can be made of the same material and process as the first insulating layer, but in order to suppress damage to the organic semiconductor layer due to the process, it is a coating film obtained by water-based coating. It is preferable. In particular,
It is a coating film containing a hydrophilic polymer and is formed by a coating solution using a solvent containing 50% or more, preferably 80% or more of water. Hydrophilic polymer is water or acidic aqueous solution,
Polymers that are soluble or dispersible in alkaline aqueous solutions, aqueous solutions of alcohols and various surfactants, such as polyvinyl alcohol and homopolymers and copolymers composed of components such as HEMA, acrylic acid, and acrylamide. It can be preferably used.

In the present invention, the second insulating layer preferably has a light transmittance of 10% or less, more preferably 1% or less. Thereby, the deterioration of the characteristics of the organic semiconductor layer due to the light can be suppressed.

The light transmittance referred to in the present specification means an average transmittance in a wavelength range where photo-generated carriers can be generated in the organic semiconductor layer. Generally, it is preferable to have a property of blocking light of 350 to 750 nm.

In order to reduce the light transmittance of the layer, a method of incorporating a coloring material such as a pigment or a dye or an ultraviolet absorber into the layer can be used.

Next is the step of forming through holes for forming the source and drain electrodes. FIG. 1 (f)
In the figure, there is shown a state in which a through hole T penetrating the second insulating layer 4 and reaching the organic semiconductor layer is formed.

The formation of the through holes is carried out by a method in which a soluble etching solution such as an organic solvent, an acid or an alkali solution is ejected by an ink jet to dissolve and wash, a general photolithography method, for example, after forming a resist pattern, A method of dissolving and washing the exposed portion, a method of dry etching such as plasma etching after forming a resist, a method of forming a through hole by ablation with an excimer laser, and the like can also be used. Further, a photosensitive resin layer described later may be used as the second insulating layer. In particular, the method of using a laser-sensitive material, using a flexible support roll, as a support,
When the gate insulating layer and the organic semiconductor layer are laminated, it is preferable because through holes can be efficiently formed continuously while conveying the support.

As the photosensitive resin layer, known materials of positive type and negative type can be used, but it is preferable to use a laser-sensitive material which can be exposed by laser. As such a photosensitive resin material, (1) JP-A-11-
No. 271969, JP-A 2001-117219, JP-A Nos. 11-311859 and 11-352691, and (2) JP-A 9-17.
9292, U.S. Pat. No. 5,340,699, JP-A-10-90885, JP-A-2000-321780, and 2001-154374, and a negative type photosensitive material having sensitivity to an infrared laser; 9-17125
No. 4, No. 5-115144, No. 10-87733,
9-43847, 10-268512, 11
-194504, 11-223936, 11-
84657, 11-174681, 7-285.
275, JP 2000-56452 A, WO 97/39.
Positive type photosensitive materials such as 894 and 98/42507, which are sensitive to infrared lasers, are mentioned. (2) and (3) are preferable because the process is not limited to a dark place.

In the photolithographic method, after that, patterning is performed using a dispersion containing metal fine particles or a conductive polymer as a material for the source electrode and the drain electrode, and heat fusion is performed if necessary to form the source electrode or the drain electrode. The organic thin film transistor can be easily manufactured with high accuracy, can be patterned in various forms, and the organic thin film transistor can be easily manufactured.

As the solvent for forming the coating solution of the photosensitive resin, propylene glycol monomethyl ether, propylene glycol monoethyl ether, methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, ethyl cellosolve acetate, dimethylformamide, dimethyl sulfoxide, dioxane, Acetone, cyclohexanone, trichloroethylene, methyl ethyl ketone, etc. are mentioned. These solvents may be used alone or in 2
Use as a mixture of two or more species.

As a method for forming the photosensitive resin layer,
Spray coating method, spin coating method, blade coating method, dip coating method, casting method, roll coating method,
A coating method such as a bar coating method or a die coating method is used.

After the photosensitive resin layer is formed, patterning exposure is performed on the photosensitive resin layer. As a light source for patterning exposure, Ar laser, semiconductor laser, H
Examples thereof include an e-Ne laser, a YAG laser, a carbon dioxide gas laser, and the like, and those having an oscillation wavelength in infrared are preferable, and a semiconductor laser is used. The output is suitably 50 mW or more, preferably 100 mW or more.

Next, the exposed photosensitive resin layer is developed. As a developer used for developing the photosensitive resin,
Aqueous alkaline developers are preferred. As the aqueous alkaline developer, for example, an aqueous solution of an alkali metal salt such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium metasilicate, potassium metasilicate, sodium phosphate dibasic, sodium phosphate tribasic, or the like. , Ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline, pyrrole, piperidine, 1 An aqueous solution in which an alkaline compound such as, 8-diazabicyclo- [5,4,0] -7-undecene or 1,5-diazabicyclo- [4,3,0] -5-nonane is dissolved can be used. The concentration of the alkaline compound in the present invention in the alkaline developer is usually 1 to 10% by mass, preferably 2 to 5% by mass.

If necessary, an anionic surfactant, an amphoteric surfactant or an organic solvent such as alcohol can be added to the developer. As the organic solvent, propylene glycol, ethylene glycol monophenyl ether, benzyl alcohol, n-propyl alcohol and the like are useful.

In the present invention, an ablation layer may be used as the photosensitive resin layer. The ablation layer used in the present invention can be composed of an energy light absorber, a binder resin, and various additives added as necessary.

As the energy light absorber, various organic and inorganic materials capable of absorbing the energy light to be applied can be used. For example, when the laser light source is an infrared laser, a pigment, a dye, a metal or a metal oxide that absorbs infrared rays is used. object,
Metal nitride, metal carbide, metal boride, graphite, carbon black, titanium black, Al, Fe,
Ferromagnetic metal powders such as metal magnetic powders containing Ni, Co or the like as a main component can be used, and among them, carbon black, cyanine-based pigments, and Fe-based ferromagnetic metal powders are preferable. The content of the energy light absorber is about 30 to 95% by mass, preferably 40 to 80% by mass of the ablation layer forming component.

The binder resin of the ablation layer can be used without particular limitation as long as it can sufficiently hold the energy light absorber fine particles, and it can be used as polyurethane resin, polyester resin, vinyl chloride resin, polyvinyl acetal resin. Examples thereof include resins, cellulosic resins, acrylic resins, phenoxy resins, polycarbonates, polyamide resins, phenol resins, and epoxy resins. The content of the binder resin is about 5 to 70% by mass of the ablation layer forming component, preferably 20 to
It is 60% by mass.

The ablation layer referred to in the present specification refers to a layer that is ablated by irradiation with high-density energy light, and the term ablate here means that the ablation layer is completely scattered by a physical or chemical change. A phenomenon in which a physical or chemical change occurs only in the vicinity of the interface with an adjacent layer, in which the material is destroyed or scattered.
Using this ablation, a resist image is formed and an electrode is formed.

High-density energy light causes ablation
There is no particular limitation as long as it is active light that can be used.
It Exposure methods include xenon lamp and halogen run
Flash exposure with a lamp, mercury lamp, etc.
You may go through the disc, or focus the laser light etc.
Scanning exposure may be performed. Output per laser beam
Infrared laser with power of 20 ~ 200mW, especially semiconductor
Body lasers are most preferably used. Energy density
Is preferably 50 to 500 mJ / cm ²And more
Preferably 100-300 mJ / cm²Is.

For the photosensitive resin layer, a water-based coatable material is preferably used. Examples of such photoresist materials include JP-A-7-104470 and 7-3.
19160, JP-A-8-328249, JP-A-9-
325482, JP-A-8-12806, JP-B-63
-41923, JP-A-5-11442, JP-A-7-
244374, 7-311309, 7-311
No. 460 is mentioned.

The through hole T may be formed at least through the second insulating layer 4 and in contact with the organic semiconductor layer 3. However, as shown in FIG. 1A, the through hole T does not penetrate the organic semiconductor layer 3. A structure, preferably a structure in which the surface layer of the organic semiconductor layer 3 is brought into contact with the source electrode and the drain electrode, is preferable in that the contact resistance can be reduced.

The structure of the organic thin film transistor in which the source material S and the drain electrode D are formed by burying the electrode material in the through hole formed in FIG. 1A is shown.

As the electrode material, those having a low electric resistance at the contact surface with the organic semiconductor layer 3 are preferable, and as will be described later in detail, a solution or dispersion liquid of a conductive polymer, a dispersion paste, or metal fine particles (for example, gold, Dispersion liquid or paste of silver, copper, platinum, etc. of several nm to several tens of μm) is used, and continuous jet type or on-demand type inkjet method using piezo element, screen printing method, lithographic printing method, etc. Can be formed by the above patterning method.

There is no limitation on the formation of the electrode, and the electrode is formed of a known conductive polymer or metal. Alternatively, patterning may be performed by known photolithography, lift-off method, or the like.

In addition, FIGS. 2A and 2B show an example of the structure of the same bottom gate type organic thin film transistor formed by changing the depth of the holes when the through holes 5 are formed.
Since the source electrode and the drain electrode only have to make contact with the organic semiconductor, (a) penetrates the second insulating layer 4 and the organic semiconductor layer 3 and stops the formation of the through hole when reaching the gate insulating layer 2. (B) is the one stopped in the organic semiconductor layer 3. The energy of the excimer laser and the irradiation time are adjusted to change the depth of the through hole.

In this way, after the gate electrode G is formed, the gate insulating layer 2, the organic semiconductor layer 3, and the second insulating layer 4 are sequentially formed, preferably by a simple coating method or the like, and then the second insulating layer is formed. By forming the through hole T reaching the gate insulating layer, highly precise patterning can be performed.

Next, FIG. 3 shows a constitutional example of an organic thin film transistor having a top gate type constitution by the method of the present invention and a manufacturing process thereof.

FIG. 3A shows the structure of the formed thin film transistor, and FIG. 3B to FIG. 3F show the manufacturing process thereof.

FIG. 3B shows the first step, in which the first electrode S'and the second electrode D'to be the source electrode and the drain electrode are formed on the support. There is.

Similarly to the gate electrode, an electrode pattern made of a conductive material such as platinum, gold, silver, nickel or the like is formed by a patterning method using a well-known photolithography method or lift-off method using a method such as vapor deposition or sputtering. Form.

Then, as shown in FIG. 3C, the first
The organic semiconductor layer 3 is uniformly formed on each electrode pattern of the electrode S'and the second electrode D'of, by using a solution of an organic semiconductor selected from π-conjugated materials such as polythiophene, for example, by a coating method. To do. The film thickness to be formed is still 10 to 3
00 nm is preferable.

After forming the organic semiconductor layer 3, a through hole T is formed in the organic semiconductor layer so as to be in contact with the first electrode S'and the second electrode D '. This is shown in FIG.

The through hole T may be formed so as to reach the support (as shown in FIG. 3D), or even if it does not reach the support, the first electrode S'and the second electrode S'are formed. The bottom surface of the through hole may remain in the organic semiconductor layer as long as it has a depth in contact with the electrode D ′.

After forming the through holes T, for example, a dispersion liquid or paste of metal fine particles (for example, particles of several nm to several tens μm of gold, silver, copper, platinum, etc.) in the through holes, the above-mentioned first A source electrode S and a drain electrode D are formed by embedding a conductive material that conducts with the electrode S ′ and the second electrode D ′. This is shown in FIG.
It was shown to. As the conductive material, an ink containing a known conductive polymer such as polythiophene whose conductivity is improved by doping or the like may be used, and it is preferably formed by a printing method.

Since the through holes are formed in advance,
This is a method with good pattern accuracy. The electrodes are electrically connected to the first and second electrodes (S ', D') formed on the support first, and together form the source electrode S and the drain electrode D.

Next, on the formed source electrode S and drain electrode D, for example, an inorganic oxide film having a high relative dielectric constant, in particular, a dielectric film such as silicon oxide is formed by a vapor deposition method or a sol-gel method. The gate insulating layer 2 is formed by a method such as spin coating ((f) in FIG. 3). The film thickness of the insulating layer is, eg, 200 nm. In addition to the sol-gel method, the atmospheric pressure plasma method is also preferable for forming the insulating layer. As the insulating layer, an organic compound resin film such as polyimide may be used.

After the gate insulating layer is formed, the gate electrode G is patterned and formed on the gate insulating layer 2 to form the structure shown in FIG.
Organic thin film transistor (TFT) as shown in (a) of
Is configured.

Further, FIG. 4 shows a constitutional example of an organic thin film transistor having another top gate type constitution and its manufacturing process. FIG. 4A shows the structure of the organic thin film transistor.

The process of forming an electrode on a support is shown in FIG.
Is the same as (b). Next, as shown in FIG. 4B, the first insulating layer 4 is formed on the patterns of the first electrode S ′ and the second electrode D ′. An inorganic oxide film having a high relative dielectric constant, particularly a dielectric film such as silicon oxide is formed as an insulating layer. It is also advantageous to form, for example, an organic compound resin film as the insulating layer and subject it to a treatment such as rubbing so as to serve as an alignment film for the organic semiconductor layer formed on the insulating layer.

Further, after the insulating layer 4 is formed, as shown in FIG. 4C, a perforation process is performed by an excimer laser to contact the first electrode S'and the second electrode D'which are formed first. Thus, the through hole T penetrating the insulating layer 4 is formed.

After forming the through holes, a conductive material is embedded in the respective through holes in the same manner as described above, and the source electrode S and the drain electrode D which are respectively bonded to the first electrode S'and the second electrode D'are respectively formed. It is formed ((d) of FIG. 4).

Next, the organic semiconductor layer 3 is formed on the insulating layer to form the structure shown in FIG.

On the source electrode S and the drain electrode D thus formed, the gate insulating layer 2 is attached ((f) of FIG. 4), and the gate electrode G is attached, thereby forming the gate electrode shown in (a) of FIG. A top gate type organic thin film transistor is constructed.

FIG. 5 shows some examples of the structure of the top gate type organic thin film transistor formed by changing the depth of formation of the through holes 5 and the timing of punching.

These top gate type organic thin film transistors can be opposed to the gate electrode through a gate insulating layer in a shape different from that of the source and drain electrodes formed on the support first, and the top electrode of the thin film transistor formation can be formed. It is convenient because the shape can be processed.

In the present invention, a π-conjugated material is used as the organic semiconductor material. For example, polypyrroles such as polypyrrole, poly (N-substituted pyrrole), poly (3-substituted pyrrole), poly (3,4-disubstituted pyrrole), polythiophene, poly (3-substituted thiophene), poly (3,4- Disubstituted thiophenes), polythiophenes such as polybenzothiophene, polyisothianaphthenes such as polyisothianaphthene, polythienylenevinylenes such as polythienylenevinylene, poly (p-phenylenevinylene) and the like. Polyaniline such as phenylene vinylene), polyaniline, poly (N-substituted aniline), poly (3-substituted aniline), poly (2,3-substituted aniline), polyacetylene such as polyacetylene, polydiacetylene such as polydiacetylene , Polyazulenes such as polyazulene, polypyrene, etc. Polycarbenes such as polypyrenes, polycarbazole, poly (N-substituted carbazole), polyselenophenes such as polyselenophene, polyfurans such as polyfuran and polybenzofuran, poly (p-phenylene) and the like. Phenylenes), polyindoles such as polyindole, polypyridazines such as polypyridazine, naphthacene, pentacene, hexacene, heptacene, dibenzopentacene, tetrabenzopentacene, pyrene, dibenzopyrene, chrysene, perylene, coronene, terylene, ovalen, Polyacenes such as quaterrylene and circumanthracene and derivatives thereof in which part of the carbons of polyacenes are replaced with atoms such as N, S and O and functional groups such as carbonyl groups (triphenodioxazine,
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, 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, the organic semiconductor layer may include, for example, acrylic acid, acetamide, dimethylamino group,
Materials having functional groups such as cyano group, carboxyl group, and nitro group, and materials serving as acceptors that accept electrons, such as benzoquinone derivatives, tetracyanoethylene and tetracyanoquinodimethane, and their derivatives,
For example, materials having functional groups such as amino groups, triphenyl groups, alkyl groups, hydroxyl groups, alkoxy groups, and phenyl groups, substituted amines such as phenylenediamine, anthracene, benzanthracene, substituted benzanthracenes, pyrene, substituted pyrene, and carbazole. And a derivative thereof, tetrathiafulvalene and a derivative thereof, and the like, containing a material that serves as a donor that is an electron donor,
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.

As methods for forming these organic semiconductor thin films, vacuum vapor deposition method, molecular beam epitaxial growth method, ion cluster beam method, low energy ion beam method, ion plating method, CVD method, sputtering method,
Examples include 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. Can be used according to 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. The thickness of the thin film made of these organic semiconductors is not particularly limited, but the characteristics of the obtained transistor are often largely influenced by the thickness of the active layer made of an organic semiconductor. Depends on
Generally 1 μm or less, particularly preferably 10 to 300 nm,
20-100 nm is more preferable.

The support used in the organic thin film transistor of the present invention is composed of glass or a flexible resin sheet, and for example, a plastic film can be used as the sheet. Examples of the plastic film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether sulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), Examples thereof include films made of cellulose triacetate (TAC), cellulose acetate propionate (CAP) and the like. As described above, by using the plastic film, it is possible to reduce the weight as compared with the case where the glass substrate is used, the portability can be enhanced, and the plastic film can have flexibility and the resistance to impact can be improved.

A transparent protective layer can be provided on the display element of the present invention, and a functional film such as an antireflection layer can be formed.

In the organic thin film transistor, the gate electrode,
As the electrode material for the source electrode and the drain electrode,
It 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 oxide / tin (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, lithium / aluminum mixture, etc. are used. However, platinum, gold, silver, copper, aluminum, indium, ITO and carbon are particularly preferable.

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

Of the above-mentioned conductive materials, the source electrode and the drain electrode are preferably those having a low electric resistance at the contact surface with the semiconductor layer.

As a method for forming the electrode, a method for forming an electrode by using a known photolithography method or a lift-off method on a conductive thin film formed by a method such as vapor deposition or sputtering using the above-mentioned raw materials, aluminum, copper, etc. There is a method of forming a resist on the metal foil by thermal transfer, ink jet or the like, and etching. Further, a solution or dispersion of a conductive polymer, a dispersion of conductive fine particles or the like may be directly patterned by an inkjet method, or may be formed from a coating film by lithography or laser ablation. Ink containing conductive polymer or conductive fine particles, conductive paste, etc. in relief, intaglio, planographic,
A method of patterning by a printing method such as screen printing can also be used.

Of these, the most preferable is a method of ejecting a solution or dispersion of the electrode material onto the through hole portion using an ink jet and patterning.

A conductive polymer or a noble metal such as gold or platinum is particularly preferable as the electrode in order to reduce the barrier with the organic semiconductor layer and the contact resistance. When a noble metal is used, JP-A 2000-239853 and JP-A 2
After forming the ultrafine particle dispersion of the metal described in JP-A No. 001-254185 and JP-A No. 11-80647 in the form of an electrode pattern by an inkjet method or the like, the solvent is dried and further heat-treated in the range of 100 ° C to 300 ° C. It is preferable to form the electrode by thermally fusing the metal fine particles.

In the present invention, the structure of the thin film transistor is explained.
The signal line, the scanning line, the material of the display electrode, the forming method, and the like when the T sheet is formed as a whole can be formed in the same manner as above.

Although various insulating films can be used as the gate insulating layer of the organic thin film transistor element of the present invention, 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, barium titanate, magnesium barium fluoride, bismuth titanate. , Strontium bismuth titanate, strontium bismuth tantalate, bismuth tantalate niobate, and yttrium trioxide.

Of these, preferred is silicon oxide,
Aluminum oxide, tantalum oxide, and titanium oxide.
Inorganic nitrides such as silicon nitride and aluminum nitride can also be preferably used.

As the method for forming the insulating layer, a vacuum vapor deposition method,
Dry process such as molecular beam epitaxial growth method, 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 A wet process such as a coating method such as a coating method, a casting method, a roll coating method, a bar coating method, or 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 a method of coating fine particles of an inorganic oxide, a liquid in which a dispersion auxiliary agent such as a surfactant is dispersed in any organic solvent or water, if necessary, or an oxide precursor, for example. A so-called sol-gel method in which a solution of an alkoxide body is applied and dried is used. Among these, 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.

The above-mentioned plasma film forming process under atmospheric pressure means
Discharged under atmospheric pressure or pressure near atmospheric pressure, plasma-exciting a reactive gas to form a thin film on a substrate, which is described in JP-A-11-133205.
JP-A-2000-185362, JP-A-11-6140
6, JP-A 2000-147209, 2000-1.
21804 and the like (hereinafter, also referred to as atmospheric pressure plasma method). As a result, a highly functional thin film can be formed by a method with high production efficiency.

As the organic compound film used for the insulating layer, polyimide, polyamide, polyester, polyacrylate, photoradical polymerization type, photocationic polymerization type photocurable resin, or copolymer containing an acrylonitrile component, polyvinylphenol. , Polyvinyl alcohol, novolac resin, cyanoethyl pullulan, and the like can also be used. The 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. The thickness of these insulating films is generally 50 nm to 3 μm, preferably 10 nm.
It is 0 nm to 1 μm.

As the method for applying the composition of each layer, known methods such as dipping, spin coating, knife coating, bar coating, blade coating, squeeze coating, reverse roll coating, gravure roll coating, curtain coating, spray coating, die coating and the like can be used. Any coating method can be used, and a coating method capable of continuous coating or thin film coating is preferably used.

[0104]

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

(Example 1) FIG. 6 shows a part of the structure of the organic thin film transistor prepared and the process of preparation.

A gate electrode G having a width of 30 μm was formed by a known photolithography method using a polyethylene terephthalate (PET) film having a thickness of about 100 μm and an aluminum layer having a thickness of 200 nm deposited on the surface.

Then, a thickness of 20 is obtained by the atmospheric pressure plasma method.
A silicon oxide film was formed as a 0 nm gate insulating layer 2. The silicon oxide film uses the apparatus described in JP-A-2000-80182, and the reactive gas is argon (98.
2% by volume), tetramethoxysilane (0.3% by volume),
A mixed gas of hydrogen gas (1.5% by volume) was used.

Then, a chloroform solution of a well-purified regioregular body of poly (3-hexylthiophene) (manufactured by Aldrich) was coated on the silicon oxide film, and chloroform was sufficiently dried at 150 ° C.
The organic semiconductor layer 3 having a thickness of 30 nm was formed. Furthermore, by applying an ethylene glycol monomethyl ether solution of novolac resin and treating at 120 ° C. for 10 minutes,
A second insulating layer 4 having a thickness of 5 μm was formed.

Next, the second insulating layer 4 was ablated with a KrF excimer laser and processed as shown in FIG. 6 (a). The hatched portion represents the laser processed surface, and the through hole T was formed in the processed surface. The width of the through hole formed by laser processing was 20 μm, and the distance between the two through holes was 10 μm. At this time, the laser power was adjusted so that the second insulating layer 4 was penetrated and the surface layer of the organic semiconductor layer was exposed.

Then, a commercially available conductive polymer (Batron P; Bayer P; poly- (ethylenedioxythiophene) and polystyrene sulfonic acid complex, water dispersion 1% by mass) was used for the excimer laser using a piezo system ink jet. It was discharged to the processed surface. FIG. 6B shows the ink droplets ejected to the through holes. I is the ink droplet of the discharged conductive polymer. (The discharged aqueous dispersion of the conductive polymer does not spread to the surface of the water-repellent second insulating layer. That is, the source,
The drain electrode is stably formed without short-circuiting) and further dried at 120 ° C. for 10 minutes to form the source and drain electrodes to obtain an organic thin film transistor.

This organic thin film transistor showed good operating characteristics of a p-channel enhancement type FET.
When the carrier mobility in the saturation region was measured,
It was 0.08 cm ² / Vs.

Example 2 An organic thin film transistor was formed according to the structure shown in FIG. A polyimide film having a thickness of about 100 μm, on which an aluminum layer having a thickness of 200 nm was deposited, was prepared. The aluminum layer was patterned by a known photolithography method to form a first electrode S'and a second electrode D'with a gap of about 30 μm. A chloroform solution of a well-purified regioregular body (made by Aldrich) of poly (3-hexylthiophene) was applied onto them, and the organic semiconductor layer 3 having a thickness of 30 nm was formed by sufficiently drying the chloroform at 150 ° C. Was formed. Next, with a KrF excimer laser, a part of the organic semiconductor layer 3 and the first electrode S ′,
A part of the second electrode D'was ablated to form two through holes T as shown in FIG. The image of patterning the electrodes and the through holes is the same as in FIG.

Next, an ultrafine particle dispersion of gold (water dispersion) disclosed in JP-A-2000-239853 is ejected onto the through hole by an ink jet, dried, and heat-treated at 250 ° C. for 10 minutes to form a gold thin film. Then, the source electrode S and the drain electrode D are formed. Further, as in Example 1, a silicon oxide film having a thickness of 200 nm is formed as the gate insulating layer 2 by the atmospheric pressure plasma method, and a commercially available conductive paste of silver is printed to obtain a gate electrode G having a width of 30 μm.
Was formed. A top gate type organic thin film transistor having the configuration shown in FIG. 3 was obtained.

This organic thin-film transistor showed good operating characteristics of a p-channel enhancement type FET.
When the carrier mobility in the saturation region was measured,
It was 0.03 cm ² / Vs.

Example 3 An organic thin film transistor was formed according to the structure shown in FIG. PE with a thickness of about 100 μm
On the surface of the S film, the copper ultrafine particle dispersion (water dispersion) disclosed in JP-A-2000-239853 is ejected by an ink jet, and the first electrode S ′ and the second electrode D are separated by a gap of about 30 μm. 'Is formed. In addition, Example 1
Similarly to the above, a silicon oxide film having a thickness of 200 nm is formed as the insulating layer 4 by the atmospheric pressure plasma method, and then the insulating layer 4, and a part of the first electrode S ′ and the second electrode are formed by the KrF excimer laser. A part of the electrode D ′ was ablated to form two through holes T as shown in FIG.

Next, as in Example 2, an ultrafine particle dispersion (water dispersion) of gold was ejected onto the through holes T by an ink jet, dried, and heat-treated at 250 ° C. for 10 minutes to form a gold thin film. The source electrode S and the drain electrode D were formed. At this time, the first electrode S ′ and the second electrode D ′ also exhibit conductivity by heat treatment.

Next, a chloroform solution of a well-purified regioregular body of poly (3-hexylthiophene) (manufactured by Aldrich) was applied onto the insulating layer 4, and 15
The organic semiconductor layer 3 having a thickness of 30 nm was formed by sufficiently drying chloroform at 0 ° C. Further, an alumina film having a thickness of 300 nm was formed as the gate insulating layer 2 by the atmospheric pressure plasma method, and a commercially available conductive paste of silver was printed to form a gate electrode having a width of 30 μm. A top gate type organic thin film transistor having the configuration shown in FIG. 4 was obtained.

This organic thin-film transistor showed good operating characteristics of a p-channel enhancement type FET.
When the carrier mobility in the saturation region was measured,
It was 0.05 cm ² / Vs.

(Example 4) n of specific resistance 0.01 Ω · cm
After forming a 2000 Å thick thermal oxide film on the type Si wafer, sublimation-purified pentacene was vapor-deposited to form an organic semiconductor layer having a thickness of 50 nm. The following composition liquid A was applied onto the organic semiconductor layer using an applicator and dried to form a photosensitive insulating layer (thickness 2 μm, light transmittance 0.5%).

<Composition Liquid A> 20 parts by mass of carbon black (manufactured by Mitsubishi Kasei Co., Ltd., trade name “MA100”) as a black pigment, polyoxyethylene alkylphenyl ether having an HLB value of 17 as a surfactant (Daiichi Kogyo Seiyaku Co., Ltd.) (Manufactured by trade name "Neugen EA177") and 75 parts by mass of water were mixed and dispersed by a sand mill. 100 parts by weight of this dispersion, 50 parts by weight of a 10% by weight aqueous solution of poly 2-hydroxyethyl methacrylate (average degree of polymerization 600), 1 part by weight of p-diazodiphenylamine as a cross-linking agent, and poly of HLB value 4 as a surfactant. 0.1 parts by mass of oxyethylene alkyl phenyl ether (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name “Neugen EA33”) was mixed to obtain a composition liquid A.

After irradiating with mercury lamp light through the mask, it was developed with water to remove the insulating layer in the unexposed portion. Baytron P; poly-
A complex of (ethylenedioxythiophene) and polystyrene sulfonic acid (aqueous dispersion 1% by mass) was discharged using a piezo system inkjet, dried, and then heat-treated at 120 ° C. for 3 minutes in a nitrogen gas atmosphere. Then, the source and drain electrodes were formed.

By the above method, the channel width W = 3 mm,
An organic thin film transistor having a channel length L = 20 μm was prepared.

This organic thin film transistor showed good operating characteristics of a p-channel enhancement type FET when driven by using a Si wafer as a gate electrode. When the carrier mobility in the saturation region was measured, it was 0.7 cm.
It was ² / Vs.

(Comparative Example 1) After gold was vapor deposited on the pentacene vapor deposition film of Comparative Example 4 of Example 4,
By photolithography, gold was etched to form a source electrode and a drain electrode. This element is FE
It didn't drive as T.

Example 5 An aluminum film having a thickness of 300 nm and a width of 300 μm was formed on a PES (polyethersulfone) film having a thickness of 150 μm by a sputtering method to obtain a gate electrode material. Next, in a 30 mass% sulfuric acid aqueous solution, anodization treatment was performed for 2 minutes using direct current supplied from a low voltage power source of 30 V so that the thickness of the anodized film was 120 nm. 1 atm, 10
After performing a steam sealing treatment in a saturated steam chamber at 0 ° C., a silicon oxide film having a thickness of 30 nm was formed by an atmospheric pressure plasma method. A well-purified chloroform solution of a regioregular body of poly (3-hexylthiophene) (manufactured by Aldrich) was prepared, and was applied to the surface of the silicon oxide film using an applicator in a N ₂ gas atmosphere, and dried at room temperature. After making it, 50 ℃, 3
Heat treatment was performed for 0 minutes. At this time, the film thickness of poly (3-hexylthiophene) was 50 nm. Further, the following composition liquid B was formed on the surface of the poly (3-hexylthiophene) film.
Was applied and dried using an applicator to form a photosensitive insulating layer (thickness 0.4 μm, light transmittance 1%).

<Composition Liquid B> 20 parts by mass of carbon black, 5 parts by mass of polyoxyethylene alkylphenyl ether having a HLB value of 17 as a surfactant (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name "Neugen EA177"), polyvinyl alcohol 30 Part by mass and 75 parts by mass of water were mixed and dispersed by a sand mill to obtain a composition liquid B.

Next, the oscillation wavelength is 830 nm and the output is 100 m.
When the pattern of the source electrode and the drain electrode was exposed with a W semiconductor laser at an energy density of 400 mJ / cm ² , the photosensitive insulating layer in the exposed portion was ablated.

An aqueous dispersion of polystyrene sulfonic acid and poly (ethylenedioxythiophene) (Baytron P manufactured by Bayer) was discharged onto the exposed portion using a piezo system inkjet, and after drying, in a nitrogen gas atmosphere,
When dried at 100 ° C., source and drain electrodes were formed. Furthermore, on the formed source and drain electrodes,
A toluene dispersion of gold fine particles (average particle size 15 nm) is discharged using a piezo system inkjet, dried, and then heat-treated at 200 ° C. for 15 minutes in a nitrogen gas atmosphere to bond the source and drain electrodes. Let Each electrode had a thickness of 3 nm on a 20 nm thick layer of polystyrene sulfonic acid and poly (ethylenedioxythiophene).
A fusion layer of fine gold particles of 00 nm is laminated.

This organic thin film transistor showed good operating characteristics of a p-channel enhancement type FET.
When the carrier mobility in the saturation region was measured,
It was 0.09 cm ² / Vs.

Example 6 Carbon black 20 was prepared in the same manner as in Example 5 except that the second insulating layer was changed as follows.
By mixing 50 parts by weight, novolac resin 50 g, and ethylene glycol monomethyl ether 100 g, the composition liquid C dispersed in a sand mill is applied and treated at 120 ° C. for 10 minutes to obtain a second insulating layer 4 having a thickness of 0.2 μm. Was formed.

This organic thin film transistor showed good operating characteristics of a p-channel enhancement type FET.
When the carrier mobility in the saturation region was measured,
It was 0.02 cm ² / Vs.

Comparative Example 2 A photosensitive polyimide was applied on a PES film having a thickness of 150 μm, and a polyimide film having a width of 20 μm and a thickness of 0.3 μm was formed by a photoresist method. After heat treatment at 100 ° C. for 5 minutes, an aqueous dispersion of a complex of polystyrenesulfonic acid and poly (ethylenedioxythiophene) was applied to both ends of the polyimide film (made by Bayer).
Baytron P) was ejected using a piezo system inkjet, dried, and then dried in a nitrogen gas atmosphere at 100
When dried at ℃, the source and drain electrodes were formed. A well-purified chloroform solution of a regioregular body of poly (3-hexylthiophene) (manufactured by Aldrich Co.) was prepared and applied to the surface of the silicon oxide film using an applicator in an N ₂ gas atmosphere,
After drying at room temperature, heat treatment was performed at 50 ° C. for 30 minutes. At this time, the film thickness of poly (3-hexylthiophene) was 50 nm.

Further, by the atmospheric pressure plasma method described above,
After providing a 200 nm-thick silicon oxide layer, the above-mentioned Ba
Ytron P was discharged using an inkjet, dried, and then dried at 100 ° C. in a nitrogen gas atmosphere to form a gate electrode. When the carrier mobility in the saturation region was measured, it was 0.002 cm ² / Vs.

The organic thin film transistor formed according to the present invention is more excellent than that formed by the conventional method.
Since patterning can be efficiently performed by a simple process using coating or the like, highly accurate patterning can be efficiently performed at low cost without requiring a large amount of equipment in the manufacturing process.

Further, although the constituent layers such as the organic semiconductor layer are formed by a simple method such as a coating method, the accuracy of the electrode pattern formation is high, so that there is little variation when the element is formed as a whole.

[0136]

EFFECT OF THE INVENTION Carrier mobility is high and current ON / O
An organic thin film transistor having a high FF value and a good switching function, and an organic thin film transistor capable of performing highly accurate patterning at low cost without complicated steps and suppressing deterioration of transistor characteristics in the manufacturing process. A manufacturing method is obtained.

[Brief description of drawings]

FIG. 1 shows a configuration example of a bottom gate type organic thin film transistor and a manufacturing process thereof.

FIG. 2 is a diagram showing a configuration example of a bottom gate type organic thin film transistor.

FIG. 3 is a diagram showing a configuration example of an organic thin film transistor having a top gate type configuration and a manufacturing process thereof.

FIG. 4 is a diagram showing a configuration example of an organic thin film transistor having a top gate type configuration and a manufacturing process thereof.

FIG. 5 is a diagram showing some configuration examples of a top gate type organic thin film transistor.

FIG. 6 is a diagram showing a part of a process of forming and manufacturing an organic thin film transistor.

[Explanation of symbols]

1 support 2 Gate insulation layer 3 Organic semiconductor layer 4 insulating layers G gate electrode S source electrode D drain electrode T through hole

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 29/28 F term (reference) 5F110 AA01 AA07 AA17 AA28 BB01 CC05 CC07 DD01 DD02 DD05 DD13 EE01 EE02 EE03 EE07 EE42 EE43 EE44 FF01 FF02 FF03 FF09 FF27 FF28 FF29 FF30 FF36 GG05 GG25 GG28 GG42 GG43 GG44 GG52 GG53 GG54 GG55 HK02 HK03 HK32 HK33 HL01 HL02 HL14 Q22 NN02 NN27 Q03 Q01 QNNQ03 Q03 NN27 Q03 Q33 NN27 Q03 NN27 Q03

Claims (14)

[Claims] 1. An organic thin film transistor in which a source electrode and a drain electrode are formed in at least an insulating layer and formed from a through hole portion in contact with an organic semiconductor channel. 2. A gate electrode, a gate insulating layer, an organic semiconductor layer, and a second layer, which are sequentially provided on the gate electrode, on the support.
2. An organic thin film transistor comprising an insulating layer and a source electrode and a drain electrode which are respectively joined to the organic semiconductor layer via two through holes penetrating the second insulating layer. 3. The organic thin film transistor according to claim 2, wherein the second insulating layer is made of a photosensitive resin. 4. The organic thin film transistor according to claim 2, wherein the second insulating layer is formed by aqueous coating. 5. A first electrode and a second electrode on a support, an organic semiconductor layer provided on the first electrode and the second electrode, two through holes penetrating the organic semiconductor layer, and through the through holes. A source electrode and a drain electrode that are respectively joined to the organic semiconductor layer, the first electrode, and the second electrode, a gate insulating layer formed on the component, and a gate electrode formed on the gate insulating layer. Organic thin film transistor. 6. A first electrode and a second electrode on a support, an insulating layer formed thereon, two through holes penetrating at least the insulating layer, and the through holes, From a source electrode and a drain electrode that are respectively joined to the first electrode and the second electrode, an organic semiconductor layer and a gate insulating layer that are sequentially formed on the constituent, and a gate electrode that is formed on the gate insulating layer. Organic thin film transistor. 7. A first electrode and a second electrode on a support, an insulating layer and an organic semiconductor layer sequentially formed on them, and two through holes penetrating at least the insulating layer and the organic semiconductor layer. A source electrode and a drain electrode that are respectively bonded to the organic semiconductor layer and the first electrode and the second electrode through the through hole, a gate insulating layer formed on the component, and a gate insulating layer An organic thin film transistor including a gate electrode formed on the substrate. 8. A gate electrode is provided on a support, a gate insulating layer, an organic semiconductor layer, and a second insulating layer are sequentially formed on the gate electrode, and the second insulating layer is penetrated to form an organic semiconductor layer. A method of manufacturing an organic thin film transistor, comprising forming two through holes in contact with each other, and forming a source electrode and a drain electrode so as to be bonded to the organic semiconductor layer through the through holes. 9. The method of manufacturing an organic thin film transistor according to claim 8, wherein the second insulating layer is formed of a photosensitive resin. 10. The method of manufacturing an organic thin film transistor according to claim 8, wherein the second insulating layer is formed by aqueous coating. 11. A first electrode and a second electrode are provided on a support, an organic semiconductor layer is formed on the electrode, and the first and second electrodes penetrate the organic semiconductor layer. After forming two through holes in contact with the electrodes, a source electrode and a drain electrode are formed so as to be bonded to the organic semiconductor layer and the first electrode and the second electrode through the through holes, respectively. A method of manufacturing an organic thin-film transistor, comprising forming a gate insulating layer on an electrode and a drain electrode, and further providing a gate electrode on the gate insulating layer. 12. A first electrode and a second electrode are provided on a support, an insulating layer is formed on them, and at least the insulating layer is penetrated to form a first electrode and a second electrode, respectively. After forming two through holes in contact with the electrodes, a source electrode and a drain electrode are formed so as to be bonded to the first electrode and the second electrode through the through holes, respectively. A method of manufacturing an organic thin film transistor, further comprising sequentially forming an organic semiconductor layer and a gate insulating layer on the top, and providing a gate electrode on the gate insulating layer. 13. A first electrode and a second electrode are provided on a support, an insulating layer and an organic semiconductor layer are sequentially formed on them, and at least the insulating layer and the organic semiconductor layer are penetrated. After providing two through holes that are in contact with the first electrode and the second electrode, the source electrode and the second electrode are formed so as to be bonded to the organic semiconductor layer, the first electrode, and the second electrode through the through holes. A method of manufacturing an organic thin film transistor, comprising forming a drain electrode, further forming a gate insulating layer on the source electrode and the drain electrode, and providing a gate electrode on the gate insulating layer. 14. The method for manufacturing an organic thin film transistor according to claim 8, wherein the electrode material solution or dispersion is discharged onto the through hole portion using an inkjet to perform patterning. .