JP4572501B2 - Method for producing organic thin film transistor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an organic thin film transistor.OfIt relates to a manufacturing method.
[0002]
[Prior art]
With the widespread use of information terminals, there is an increasing need for flat panel displays as computer displays. In addition, with the progress of computerization, the information provided by paper media has increased the opportunity to be provided electronically, and as a mobile display medium that is thin, light and easy to carry, electronic paper or digital The need for paper is also increasing.
[0003]
In general, in a flat display device, a display medium is formed using an element utilizing liquid crystal, organic EL, electrophoresis, or the like. In such a display medium, a technique using an active drive element formed of a thin film transistor (TFT) as an image drive element has become mainstream in order to ensure uniformity of screen brightness, screen rewrite speed, and the like.
[0004]
Here, the TFT element is usually formed on a glass substrate, mainly a semiconductor thin film such as a-Si (amorphous silicon) or p-Si (polysilicon), or a metal thin film such as a source, drain, or gate electrode on the substrate. Manufactured by sequentially forming. The production of flat panel displays using TFTs usually requires high-precision photolithographic processes in addition to vacuum equipment such as CVD and sputtering and thin film forming processes that require high-temperature processing processes. The load is very large. Furthermore, along with the recent needs for larger display screens, their costs have become enormous.
[0005]
In recent years, research and development of organic TFT elements using organic semiconductor materials has been actively promoted as a technique to compensate for the disadvantages of conventional TFT elements. Since this organic TFT element can be manufactured by a low-temperature process, it is said that a light and hard-to-break resin substrate can be used, and that a flexible display using a resin film as a support can be realized. Further, by using an organic semiconductor material that can be manufactured by a wet process such as printing or coating under atmospheric pressure, a display with excellent productivity and a very low cost can be realized.
[0006]
An important requirement in this organic TFT technology is high-precision patterning of channels. In the above-mentioned patents and JP-A-10-190001, JP-A-2000-307172, etc., high-precision photolithography is required for forming the channel portion, and it is difficult to form a patterning. A large amount of equipment is required and the cost becomes high. The present invention makes it possible to form a high-precision pattern more easily and greatly improves these problems.
[0007]
As an organic thin film transistor, for example, WO01 / 47043 discloses an all-polymer type organic TFT technology. Although a simple process by ink jet or coating is proposed, the carrier mobility of the element is low, the gate voltage is high, and the current value in the switching ON state is low. There is a problem that the ON / OFF value of the current is low.
[0008]
In addition, in a process subsequent to the formation of the organic semiconductor layer, for example, a coating process of a photosensitive resin material for patterning or a developing process of the photosensitive resin layer, a coating solvent or a developer component used in the process, etc. Due to the influence of the above, there is a problem that the characteristics as a transistor deteriorate.
[0009]
[Problems to be solved by the invention]
High-accuracy patterning can be performed at low cost without going through complicated manufacturing processes, high carrier mobility, low gate voltage, high current value in switching ON state, and therefore current ON / OFF value It is to obtain an organic thin film transistor having a high driving frequency and a high driving frequency, and to obtain a method for producing an organic thin film transistor capable of suppressing deterioration of the characteristics of the transistor in the production process.
[0010]
[Means for Solving the Problems]
  The above object of the present invention is achieved by the following means (1) to (7).
  (1) 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 penetrated through the second insulating layer by laser ablation. Two through holes that contact the layer are formed, and the source electrode is connected to the organic semiconductor layer through the through holes.as well asA method for producing an organic thin film transistor, comprising forming a drain electrode.
  (2) The method for producing an organic thin film transistor according to (1), wherein the second insulating layer is formed by water-based coating.
  (3) The method for producing an organic thin film transistor according to (1) or (2), wherein the second insulating layer contains a hydrophilic polymer.
  (4) A first electrode and a second electrode are provided on a support, an organic semiconductor layer is formed on the electrode, and the organic semiconductor layer is penetrated by laser ablation. After forming 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, respectively, through the through hole. A method for producing an organic thin film transistor, comprising: forming a gate insulating layer on the source electrode and the drain electrode; and further providing a gate electrode on the gate insulating layer.
  (5) A first electrode and a second electrode are provided on the support, an insulating layer is formed on the first electrode, and at least the insulating layer is penetrated by laser ablation. After forming two through holes in contact with the two electrodes, a source electrode and a drain electrode are formed so as to be joined to the first electrode and the second electrode through the through holes, respectively. A method for producing an organic thin film transistor, further comprising: sequentially forming an organic semiconductor layer and a gate insulating layer on the drain electrode; and attaching the gate electrode on the gate insulating layer.
  (6) A first electrode and a second electrode are provided on a support, an insulating layer and an organic semiconductor layer are sequentially formed thereon, and at least the insulating layer and the organic semiconductor layer are penetrated by laser ablation. After providing two through holes in contact with the first electrode and the second electrode, the source is connected to the organic semiconductor layer, the first electrode, and the second electrode through the through holes. An organic thin film transistor manufacturing method comprising: forming an electrode and a drain electrode; forming a gate insulating layer on the source electrode and the drain electrode; and providing a gate electrode on the gate insulating layer.
  (7) The electrode material solution or dispersion is used for inkjet,SaidThrough HoLeEjected and patternedThe source electrode and drainAn electrode is formed, The manufacturing method of the organic thin-film transistor of any one of said (1)-(6) characterized by the above-mentioned.
  Hereinafter, 1 to 14 are means for reference.
[0011]
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.
[0012]
2. On the support, through the gate electrode, the gate insulating layer sequentially attached on the gate electrode, the organic semiconductor layer, the second insulating layer, and the two through holes penetrating the second insulating layer, the organic semiconductor An organic thin film transistor comprising a source electrode and a drain electrode which are respectively bonded to the layers.
[0013]
3. 3. The organic thin film transistor according to 2 above, wherein the second insulating layer is made of a photosensitive resin.
[0014]
4). 4. The organic thin film transistor according to 2 or 3 above, wherein the second insulating layer is formed by aqueous coating.
[0015]
5. On the support, the first electrode and the second electrode, the organic semiconductor layer attached thereon, two through holes penetrating the organic semiconductor layer, the organic semiconductor layer and An organic thin film transistor comprising a source electrode and a drain electrode joined to a first electrode and a second electrode, a gate insulating layer formed on the structure, and a gate electrode formed on the gate insulating layer.
[0016]
6). On the support, the first electrode and the second electrode, the insulating layer formed thereon, at least two through holes penetrating the insulating layer, the first electrode through the through hole, 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 structure, and a gate electrode formed on the gate insulating layer.
[0017]
7). On the support, a first electrode and a second electrode, an insulating layer, 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 joined to the organic semiconductor layer, the first electrode, and the second electrode, a gate insulating layer formed on the structure, and a gate formed on the gate insulating layer, respectively. An organic thin film transistor comprising electrodes.
[0018]
8). A gate electrode is provided on the support, a gate insulating layer, an organic semiconductor layer, and a second insulating layer are sequentially formed on the gate electrode. Two through holes that penetrate the second insulating layer and are in contact with 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.
[0019]
9. 7. The method of manufacturing an organic thin film transistor according to 6 above, wherein the second insulating layer is made of a photosensitive resin.
[0020]
10. 10. The method for producing an organic thin film transistor as described in 8 or 9 above, wherein the second insulating layer is formed by aqueous coating.
[0021]
11. A first electrode and a second electrode are provided on the support, an organic semiconductor layer is formed on the electrode, and two electrodes that penetrate the organic semiconductor layer and 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 joined 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 on the source electrode and the drain electrode. A method for producing 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.
[0022]
12 A first electrode and a second electrode are provided on a support, an insulating layer is formed on the first electrode, and two electrodes that penetrate at least the insulating layer and are in contact with 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 joined to the first electrode and the second electrode through the through hole, and the source electrode and the drain electrode are further sequentially formed. A method for producing an organic thin film transistor, comprising: forming an organic semiconductor layer and a gate insulating layer; and providing a gate electrode on the gate insulating layer.
[0023]
13. A first electrode and a second electrode are provided on the support, and an insulating layer and an organic semiconductor layer are sequentially formed on the first electrode and the second electrode, and at least the first electrode penetrating 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 joined to the organic semiconductor layer, the first electrode, and the second electrode, respectively, through the through hole. A method of manufacturing an organic thin film transistor, further comprising forming a gate insulating layer on the source electrode and the drain electrode, and attaching a gate electrode on the gate insulating layer.
[0024]
14 14. The method for producing an organic thin film transistor according to any one of 8 to 13, wherein the electrode material solution or the dispersion liquid is ejected to a through-hole portion using ink jet and patterned.
[0025]
Hereinafter, the present invention will be specifically described with reference to the following embodiments.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
An organic thin film transistor using the organic semiconductor material of the present invention as an active semiconductor layer and a manufacturing method thereof will be described below with reference to FIGS.
[0027]
FIG. 1 shows a configuration example of a bottom gate type organic thin film transistor of the present invention and a manufacturing process thereof.
[0028]
FIG. 1A shows a configuration example of an organic thin film transistor to be manufactured. That is, a gate electrode G is provided on the support 1, a gate insulating layer 2, an organic semiconductor layer 3, a source electrode S and a drain electrode D provided in contact with the organic semiconductor layer, and a protective film. At the same time, the second insulating layer 4 is used to stabilize the interface barrier between the source and drain electrodes and the organic semiconductor layer.
[0029]
FIG. 1B shows a state in which the gate electrode G is provided on the support. As described later, the support 1 may be made of glass or a flexible resin sheet such as polyethylene terephthalate (PET).
[0030]
As will be described later, the gate electrode is formed of a conductive material such as platinum, gold, silver, or nickel. As a method of forming the electrode, a conductive thin film is formed using a method such as vapor deposition or sputtering using the above as a raw material. It can be obtained by a patterning method using a known photolithographic method or lift-off method. Further, the conductive fine particle dispersion or the like may be printed and patterned by a printing method, an ink jet method or the like.
[0031]
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 to which the gate electrode G is attached.
[0032]
As the gate insulating layer, an inorganic oxide film having a high relative dielectric constant, in particular, a film of silicon oxide, silicon nitride, aluminum oxide or the like is applied on the gate electrode pattern. As a method for forming an inorganic oxide film, a vacuum deposition method, a CVD method, a sputtering method, a dry process so-called vapor phase deposition method such as an atmospheric pressure plasma method, a spin coating method using a so-called sol-gel method, a blade coating method, Examples thereof include wet processes such as coating methods such as dip coating and die coating, and patterning methods such as printing and inkjet. 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 100 nm to 1 μm.
[0033]
As the insulating film used for the insulating layer, polyimide, polyamide, or an organic compound film such as a photocurable resin can also be used. In the case of an organic compound film, it is preferably formed by a wet process such as coating. An inorganic oxide film and an organic oxide film can be laminated and used together.
[0034]
Next, as shown in FIG. 1D, the organic semiconductor layer 3 is coated on the formed gate insulating layer 2.
[0035]
Π-conjugated materials such as polypyrrole and polythiophene are used as organic semiconductors, and also vapor deposition methods such as vacuum deposition, CVD, and sputtering, plasma polymerization, electrolytic polymerization, chemical polymerization, or spray coating These organic semiconductor thin films are formed by a coating method such as a spin coating method or an LB method. However, among these, from the viewpoint of productivity, a coating method capable of easily and precisely forming 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, but the characteristics of the obtained transistor are often greatly influenced by the thickness of the active layer made of the organic semiconductor. Although it varies depending on the semiconductor, it is generally 1 μm or less, preferably 10 to 300 nm.
[0036]
After the organic semiconductor thin film is formed, a second insulating layer 4 is further provided as shown in FIG.
[0037]
The second insulating layer can be made of the same material and process as the first insulating layer. However, in order to suppress damage to the organic semiconductor layer due to the process, it is preferable to use a coating film obtained by aqueous coating. . Specifically, 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. The hydrophilic polymer is a polymer that is soluble or dispersible in water or an acidic aqueous solution, an alkaline aqueous solution, an aqueous solution of alcohols or various surfactants, such as polyvinyl alcohol, HEMA / acrylic acid / acrylamide. Homopolymers and copolymers comprising these components can be suitably used.
[0038]
In the present invention, the second insulating layer preferably has a light transmittance of 10% or less, more preferably 1% or less. As a result, the light of the organic semiconductor layer
It is possible to suppress deterioration of characteristics.
[0039]
The light transmittance referred to in this specification indicates an average transmittance in a wavelength region where photo-generated carriers can be generated in the organic semiconductor layer. In general, it is preferable to have the ability to shield light from 350 to 750 nm.
[0040]
In order to reduce the light transmittance of the layer, a method of incorporating a color material such as a pigment or a dye or an ultraviolet absorber into the layer can be used.
[0041]
Next is a step of forming through holes for forming source and drain electrodes. FIG. 1F shows a state in which a through hole T that reaches the organic semiconductor layer through the second insulating layer 4 is formed.
[0042]
Through holes are formed by discharging a soluble etching solution such as an organic solvent, an acid, or an alkali solution with an inkjet, dissolving and cleaning, a general photolithography method, for example, after forming a resist pattern, and then exposing an exposed portion. A method of dissolving and cleaning, a method of dry etching such as plasma etching after resist formation, a method of forming a through hole by ablation with an excimer laser, or the like can also be used. Moreover, you may use the photosensitive resin layer mentioned later for a 2nd insulating layer. In particular, a method using a laser-sensitive material uses a flexible support roll, and when the gate insulating layer or the organic semiconductor layer is laminated using the flexible support roll as a support, the support is transported continuously. It is preferable because a through hole can be efficiently formed.
[0043]
As the photosensitive resin layer, a known positive or negative material can be used, but it is preferable to use a laser-sensitive material that can be exposed by a laser. Examples of such photosensitive resin materials include: (1) Dye-sensitized photopolymerizable photosensitive materials such as JP-A-11-271969, JP-A-2001-117219, JP-A-11-311859, and JP-A-11-352691. (2) Negative type having sensitivity to infrared laser such as JP-A-9-179292, US Pat. No. 5,340,699, JP-A-10-90885, JP-A-2000-321780, 2001-154374 Photosensitive materials (3) JP-A-9-171254, 5-115144, 10-87733, 9-43847, 10-268512, 11-194504, 11-223936, 11-84657, 11-174681, 7-285275, JP 2000-56452, WO 97/39894, 98 Positive photosensitive material having photosensitivity to infrared laser, such as 42507 and the like. Preference is given to (2) and (3) in that the process is not limited to a dark place.
[0044]
In the photolithographic method, after that, patterning is performed using a metal fine particle-containing dispersion or conductive polymer as a material for the source electrode and the drain electrode, and heat fusion is performed as necessary, so that the source electrode or the drain electrode can be easily raised. It becomes possible to manufacture with high precision, patterning in various forms becomes easy, and an organic thin film transistor can be easily manufactured.
[0045]
Solvents for forming the coating solution of photosensitive resin include propylene glycol monomethyl ether, propylene glycol monoethyl ether, methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, ethyl cellosolve acetate, dimethylformamide, dimethyl sulfoxide, dioxane, acetone, cyclohexanone , Trichlorethylene, methyl ethyl ketone and the like. These solvents are used alone or in admixture of two or more.
[0046]
As a method for forming the photosensitive resin layer, a coating method such as a spray coating method, a spin coating method, a blade coating method, a dip coating method, a casting method, a roll coating method, a bar coating method, or a die coating method is used.
[0047]
When the photosensitive resin layer is formed, patterning exposure is performed on the photosensitive resin layer. Examples of the light source for performing patterning exposure include an Ar laser, a semiconductor laser, a He—Ne laser, a YAG laser, a carbon dioxide laser, and the like, and those having an oscillation wavelength in the infrared, preferably a semiconductor laser. The output is suitably 50 mW or more, preferably 100 mW or more.
[0048]
Next, the exposed photosensitive resin layer is developed. A water-based alkaline developer is suitable as the developer used for developing the photosensitive resin. Examples of the aqueous alkaline developer include aqueous solutions of alkali metal salts such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium metasilicate, potassium metasilicate, dibasic sodium phosphate, and tribasic sodium phosphate. , Ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline, pyrrole, piperidine, 1 , 8-diazabicyclo- [5,4,0] -7-undecene, 1,5-diazabicyclo- [4,3,0] -5-nonane and other aqueous solutions in which alkaline compounds are dissolved. In the present invention, the concentration of the alkaline compound in the alkaline developer is usually 1 to 10% by mass, preferably 2 to 5% by mass.
[0049]
If necessary, an organic solvent such as an anionic surfactant, an amphoteric surfactant or 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.
[0050]
In the present invention, an ablation layer may be used for 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.
[0051]
As the energy light absorber, various organic and inorganic materials that absorb energy light to be irradiated can be used. For example, when the laser light source is an infrared laser, a pigment, a dye, a metal, a metal oxide, a metal that absorbs infrared light Ferrite metal powder such as metal magnetic powder mainly composed of nitride, metal carbide, metal boride, graphite, carbon black, titanium black, Al, Fe, Ni, Co, etc. can be used. Black, cyanine-based pigments, and Fe-based ferromagnetic metal powders are preferred. Content of an energy light absorber is about 30-95 mass% of an ablation layer formation component, Preferably it is 40-80 mass%.
[0052]
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. The polyurethane resin, polyester resin, vinyl chloride resin, polyvinyl acetal resin, cellulose Resin, acrylic resin, phenoxy resin, polycarbonate, polyamide resin, phenol resin, epoxy resin and the like. The content of the binder resin is about 5 to 70% by mass, preferably 20 to 60% by mass, of the ablation layer forming component.
[0053]
The ablation layer in this specification refers to a layer that is ablated by irradiation with high-density energy light. The ablation referred to here is a part in which the ablation layer is completely scattered due to physical or chemical changes, and a part of the ablation layer is destroyed. Or a phenomenon in which a physical or chemical change occurs only near the interface between adjacent layers.
Using this ablation, a resist image is formed and electrodes are formed.
[0054]
The high-density energy light can be used without particular limitation as long as it is active light that generates ablation. As an exposure method, flash exposure using a xenon lamp, a halogen lamp, a mercury lamp, or the like may be performed through a photomask, or scanning exposure may be performed by converging laser light or the like. An infrared laser, particularly a semiconductor laser, whose output per laser beam is 20 to 200 mW is most preferably used. The energy density is preferably 50 to 500 mJ / cm.²More preferably, it is 100-300mJ / cm²It is.
[0055]
The photosensitive resin layer is preferably made of a water-based material. Examples of such photoresist materials include JP-A-7-104470, JP-A-7-319160, JP-A-8-328249, JP-A-9-325482, JP-A-8-12806, and JP-B-63-41923. And JP-A-5-11442, JP-A-7-244374, JP-A-7-31309, and JP-A-7-31460.
[0056]
The through hole T may be formed so as to penetrate at least the second insulating layer 4 and be in contact with the organic semiconductor layer 3, but preferably has a configuration that does not penetrate the organic semiconductor layer 3 as shown in FIG. The configuration in which the surface layer of the organic semiconductor layer 3 is in contact with the source electrode and the drain electrode is preferable in that the contact resistance can be reduced.
[0057]
FIG. 1A shows a structure of an organic thin film transistor in which an electrode material is embedded in the through hole formed and a source electrode S and a drain electrode D are formed.
[0058]
The electrode material preferably has a low electrical resistance at the contact surface with the organic semiconductor layer 3, and will be described in detail later. A conductive polymer solution or dispersion, a dispersion paste, or metal fine particles (for example, gold, silver, copper) Any patterning method such as on-demand inkjet method, screen printing method, lithographic printing method using a continuous jet type or piezo element using a dispersion liquid or paste of particles of several nm to several tens of μm such as platinum Can be formed.
[0059]
There is no restriction | limiting in formation of an electrode, It forms with a well-known conductive polymer and a metal. Or you may pattern by a well-known photolithograph, the lift-off method, etc.
[0060]
FIGS. 2A and 2B show a configuration example of the same bottom gate type organic thin film transistor formed by changing the depth of the perforation when the through hole 5 is formed. Since the source electrode and the drain electrode only have to be in contact with the organic semiconductor, (a) penetrates the second insulating layer 4 and the organic semiconductor layer 3 and stops forming the through hole when reaching the gate insulating layer 2. (B) is stopped in the organic semiconductor layer 3. To change the depth of through-hole drilling, adjust the excimer laser energy and irradiation time.
[0061]
In this manner, after the gate electrode G is formed, the gate insulating layer 2, the organic semiconductor layer 3, and the second insulating layer 4 are preferably formed sequentially by a simple coating method or the like, and then the second insulating layer to the gate insulating layer. High-precision patterning can be performed by forming the through-hole T reaching the diameter.
[0062]
Next, FIG. 3 shows a configuration example of an organic thin film transistor having a top gate type configuration according to the method of the present invention and a manufacturing process thereof.
[0063]
FIG. 3A shows the configuration of the thin film transistor in which the thin film transistor is formed, and FIGS. 3B to 3F show the manufacturing process.
[0064]
FIG. 3B shows a state where the first electrode S ′ and the second electrode D ′, which are the source electrode and the drain electrode, are formed on the support, which is the first step.
[0065]
Similarly to the gate electrode, an electrode pattern made of a conductive material such as platinum, gold, silver, or nickel is formed by a patterning method using a known photolithography method or a lift-off method using a method such as vapor deposition or sputtering.
[0066]
Next, as shown in FIG. 3C, the organic semiconductor layer 3 is uniformly selected from π-conjugated materials such as polythiophene on the electrode patterns of the first electrode S ′ and the second electrode D ′. For example, it is formed by a coating method using an organic semiconductor solution. The film thickness to be formed is preferably 10 to 300 nm.
[0067]
After the organic semiconductor layer 3 is formed, 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.
[0068]
The through hole T may be formed so as to reach the support (as shown in FIG. 3D), or the first electrode S ′ and the second electrode D ′ may be formed without reaching the support. The bottom surface of the through hole may be stopped in the organic semiconductor layer as long as the depth is in contact with the organic semiconductor layer.
[0069]
After the through hole T is formed, the first electrode S ′ such as a dispersion liquid or paste of metal fine particles (for example, particles of several nm to several tens μm such as gold, silver, copper, platinum, etc.) in the through hole. In addition, a source electrode S and a drain electrode D are formed by embedding a conductive material that is electrically connected to the second electrode D ′. This is shown in FIG. 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.
[0070]
Since the through holes are formed in advance, the pattern accuracy is improved. The electrode is electrically connected to the first and second electrodes (S ′, D ′) first formed on the support, and constitutes the source electrode S and the drain electrode D together.
[0071]
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 spin-coated using a vapor deposition method or a sol-gel method. The gate insulating layer 2 is formed by such a method ((f) in FIG. 3). The thickness of the insulating layer is, for example, 200 nm. In addition to the sol-gel method, an 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.
[0072]
After the gate insulating layer is formed, the gate electrode G is patterned on the gate insulating layer 2 to form an organic thin film transistor (TFT) as shown in FIG.
[0073]
Further, FIG. 4 shows a configuration example of an organic thin film transistor having another top gate type configuration and a manufacturing process thereof. FIG. 4A shows the configuration of the organic thin film transistor.
[0074]
The step of forming the electrode on the support is the same as that shown in FIG. 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. For example, it is also advantageous to form an organic compound resin film as the insulating layer, and perform a process such as rubbing on this to serve as an alignment film for the organic semiconductor layer formed on the insulating layer.
[0075]
Further, after the insulating layer 4 is formed, as shown in FIG. 4 (c), an excimer laser is used to perform perforation processing so that the first electrode S ′ and the second electrode D ′ formed first are in contact with each other. A through hole T penetrating the layer 4 is formed.
[0076]
After the through holes are formed, a conductive material is buried in the respective through holes in the same manner as described above, and the source electrode S and the drain electrode D that are respectively joined to the first electrode S ′ and the second electrode D ′ are formed ( (D) of FIG.
[0077]
Next, the organic semiconductor layer 3 is formed on the insulating layer, and the structure shown in FIG.
[0078]
The gate insulating layer 2 is provided on the source electrode S and the drain electrode D thus formed (FIG. 4F), and the gate electrode G is further provided so that the top gate type shown in FIG. An organic thin film transistor is constructed.
[0079]
FIG. 5 shows some structural examples of the top gate type organic thin film transistor formed by changing the depth of forming the through hole 5 and the timing of drilling.
[0080]
These top gate type organic thin film transistors can be opposed to the gate electrode through the gate insulating layer in a shape different from the source and drain electrodes formed on the support first. It is convenient.
[0081]
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- Di-substituted thiophene), polythiophenes such as polybenzothiophene, polyisothianaphthenes such as polyisothianaphthene, polythienylene vinylenes such as polythienylene vinylene, and poly (p-) such as poly (p-phenylene vinylene). Phenylene vinylenes), polyaniline, poly (N-substituted aniline), poly (3-substituted aniline), poly (aniline) such as poly (2,3-substituted aniline), polyacetylenes such as polyacetylene, and polydiacetylenes such as polydiacetylene , Polyazulenes such as polyazulene, polypyrene, etc. Polypyrazoles, polycarbazoles such as polycarbazole and poly (N-substituted carbazole), polyselenophenes such as polyselenophene, polyfurans such as polyfuran and polybenzofuran, and poly (p-phenylene) such as poly (p-phenylene) Phenylene) s, polyindoles such as polyindole, polypyridazines such as polypyridazine, naphthacene, pentacene, hexacene, heptacene, dibenzopentacene, tetrabenzopentacene, pyrene, dibenzopyrene, chrysene, perylene, coronene, terylene, ovalene, Derivatives (triphenodioxazine, triphenodithiazine) in which a part of carbon of polyacenes such as quaterylene and circumanthracene and polyacenes are substituted with atoms such as N, S and O and functional groups such as carbonyl groups Hexacene-6,15-quinone, etc.), polyvinylcarbazole, polyphenylene sulfide, or the like can be used polycyclic condensate described in polymers and JP 11-195790, such as poly vinyl sulfide. In addition, α-sexual thiophene, α, ω-dihexyl-α-sexual thiophene, α, ω-dihexyl-α-kinkethiophene, α, ω-bis, which are, for example, thiophene hexamers having the same repeating units as these polymers Oligomers such as (3-butoxypropyl) -α-sexithiophene and styrylbenzene derivatives can also be suitably used. 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, N, N'-bis (1H, 1H-perfluorooctyl), N, N'-bis (1H, 1H-perfluorobutyl) and N, N '-Dioctylnaphthalene-1,4,5,8-tetracarboxylic acid diimide derivatives, naphthalene tetracarboxylic acid diimides such as naphthalene-2,3,6,7-tetracarboxylic acid diimide, and anthracene-2,3, Condensation of anthracene tetracarboxylic acid diimides such as 6,7-tetracarboxylic acid diimide Tetracarboxylic acid diimides, C₆₀, C₇₀, C₇₆, C₇₈, C₈₄Examples thereof include carbon fullerenes, carbon nanotubes such as SWNT, merocyanine dyes, and dyes such as hemicyanine dyes.
[0082]
Among these π-conjugated materials, thiophene, vinylene, thienylene vinylene, phenylene vinylene, p-phenylene, a substituent thereof, or two or more of these are used as a repeating unit, and the number n of the repeating units is 4 to 4 At least 1 selected from the group consisting of an oligomer of 10 or a polymer in which the number n of the repeating units is 20 or more, a condensed polycyclic aromatic compound such as pentacene, fullerenes, condensed ring tetracarboxylic acid diimides, and metal phthalocyanine. Species are preferred.
[0083]
Other organic semiconductor materials include tetrathiafulvalene (TTF) -tetracyanoquinodimethane (TCNQ) complex, bisethylenetetrathiafulvalene (BEDTTTTF) -perchloric acid complex, BEDTTTTF-iodine complex, TCNQ-iodine complex. Organic molecular complexes such as can also be used. Furthermore, (sigma) conjugated polymers, such as polysilane and a polygerman, organic-inorganic hybrid material as described in Unexamined-Japanese-Patent No. 2000-260999, etc. can be used.
[0084]
In the present invention, for example, a material having a functional group such as acrylic acid, acetamide, dimethylamino group, cyano group, carboxyl group, nitro group, benzoquinone derivative, tetracyanoethylene, and tetracyanoquinodimethane are used in the organic semiconductor layer. And materials that can accept electrons, such as derivatives thereof, materials that have functional groups such as amino groups, triphenyl groups, alkyl groups, hydroxyl groups, alkoxy groups, and phenyl groups, substituted amines such as phenylenediamine , So-called doping, containing materials that serve as donors of electrons such as anthracene, anthracene, benzoanthracene, substituted benzoanthracene, pyrene, substituted pyrene, carbazole and its derivatives, tetrathiafulvalene and its derivatives, etc. Processing Good.
[0085]
The doping means introducing an electron-accepting molecule (acceptor) or an electron-donating molecule (donor) into the organic semiconductor layer thin film as a dopant. Accordingly, the doped thin film is a thin film containing the condensed polycyclic aromatic compound and the dopant. Either an acceptor or a donor can be used as the dopant used in the present invention. Cl as this acceptor₂, Br₂, I₂, ICl, ICl_Three, IBr, IF and other halogens, PF_Five, AsF_Five, SbF_Five, BF_Three, BCl_Three, BBr_Three, SO_ThreeLewis acids such as HF, HC1, HNO_Three, H₂SO_Four, HClO_Four, FSO_ThreeH, ClSO_ThreeH, CF_ThreeSO_ThreeProtic acids such as H, organic acids such as acetic acid, formic acid and amino acids, FeCl_Three, FeOCl, TiCl_Four, ZrCl_Four, HfCl_Four, NbF_Five, NbCl_Five, TaCl_Five, MoCl_Five, WF_Five, WCl₆, UF₆, LnCl_ThreeTransition metal compounds such as (Ln = La, Ce, Nd, Pr, and other lanthanoids and Y), Cl^-, Br^-, I^-, ClO_Four ^-, PF₆ ^-, AsF_Five ^-, SbF₆ ^-, BF_Four ^-And electrolyte anions such as sulfonate anions. As donors, alkali metals such as Li, Na, K, Rb, and Cs, alkaline earth metals such as Ca, Sr, and Ba, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, and Dy , Ho, Er, Yb and other rare earth metals, ammonium ions, R_FourP⁺, R_FourAs⁺, R_ThreeS⁺And acetylcholine. As a method for doping these dopants, either a method of preparing an organic semiconductor thin film in advance and then introducing the dopant later, or a method of introducing a dopant when forming the organic semiconductor thin film can be used. As the former method, gas phase doping using a dopant in a gas state, liquid phase doping in which a solution or liquid dopant is brought into contact with the thin film, and solid doping in which a dopant in a solid state is brought into contact with the thin film and diffusion doping is performed. Examples of the phase doping method can be given. In liquid phase doping, the efficiency of doping can be adjusted by applying electrolysis. In the latter method, a mixed solution or dispersion of an organic semiconductor material and a dopant may be applied and dried simultaneously. For example, when using a vacuum evaporation method, a dopant can be introduce | transduced by co-evaporating a dopant with an organic-semiconductor material. When a thin film is formed by a sputtering method, the dopant can be introduced into the thin film by sputtering using a binary target of an organic semiconductor material and a dopant. Still other methods include chemical doping such as electrochemical doping, photoinitiated doping, and physics such as ion implantation shown in the publication (Industrial Materials, Vol. 4, No. 4, 55, 1986). Any of the chemical dopings can be used.
[0086]
These organic semiconductor thin film creation methods include vacuum deposition, molecular beam epitaxial growth, ion cluster beam method, low energy ion beam method, ion plating method, CVD method, sputtering method, plasma polymerization method, electrolytic polymerization method, Examples include chemical polymerization, spray coating, spin coating, blade coating, dip coating, casting, roll coating, bar coating, die coating, and LB, which can be used depending on the material. However, in terms of productivity, spin coating method, blade coating method, dip coating method, roll coating method, bar coating method, die coating method, etc. that can form a thin film easily and precisely using a solution of 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 greatly influenced by the thickness of the active layer made of the organic semiconductor. Varies by Generally, it is 1 μm or less, particularly preferably 10 to 300 nm, more preferably 20 to 100 nm.
[0087]
The support used for the organic thin film transistor of the present invention is made 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), polyethersulfone (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. Thus, by using a plastic film, the weight can be reduced as compared with the case of using a glass substrate, the portability can be increased, and flexibility can be improved and resistance to impact can be improved.
[0088]
In addition, a transparent protective layer can be provided on the display element of the present invention, and for example, a functional film such as an antireflection layer can be formed.
[0089]
The electrode material for the gate electrode, source electrode, and drain electrode in the organic thin film transistor is not particularly limited as long as it is a conductive material. Platinum, gold, silver, nickel, chromium, copper, iron, tin, antimony lead, tantalum , Indium, palladium, tellurium, rhenium, iridium, aluminum, ruthenium, germanium, molybdenum, tungsten, tin oxide / antimony, indium tin oxide (ITO), fluorine-doped zinc oxide, zinc, carbon, graphite, glassy carbon, silver paste And carbon paste, lithium, beryllium, sodium, magnesium, potassium, calcium, scandium, titanium, manganese, zirconium, gallium, niobium, sodium, sodium-potassium alloy, magnesium, lithium, aluminum Ni, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide mixture, lithium / aluminum mixture, etc. are used, especially platinum, gold, silver, copper, aluminum, Indium, ITO and carbon are preferred.
[0090]
Alternatively, a known conductive polymer whose conductivity is improved by doping or the like, for example, conductive polyaniline, conductive polypyrrole, conductive polythiophene, a complex of polyethylenedioxythiophene and polystyrenesulfonic acid, or the like is also preferably used.
[0091]
Of the conductive materials listed above, the source electrode and the drain electrode are preferably those having low electrical resistance at the contact surface with the semiconductor layer.
[0092]
As a method for forming an electrode, a method for forming an electrode using a known photolithographic method or a lift-off method, using a conductive thin film formed by a method such as vapor deposition or sputtering using the above as a raw material, or a metal foil such as aluminum or copper There is a method in which a resist is formed and etched by thermal transfer, ink jet or the like. Further, a solution or dispersion of a conductive polymer, a conductive fine particle dispersion, or the like may be directly patterned by an ink jet method, or may be formed from a coating film by lithography or laser ablation. Furthermore, 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 relief printing, intaglio printing, planographic printing, or screen printing can be used.
[0093]
Among these, the most preferable method is a method of discharging and patterning a solution or dispersion of an electrode material to a through-hole portion using an ink jet.
[0094]
In order to reduce the barrier with the organic semiconductor layer and lower the contact resistance, a conductive polymer or a noble metal such as gold or platinum is particularly preferable as the electrode. In the case of using a noble metal, after forming an ultrafine particle dispersion of a metal described in JP-A No. 2000-239853, JP-A No. 2001-254185 and JP-A No. 11-80647 into an electrode pattern by an inkjet or the like, a solvent is used. It is preferable to form electrodes by thermally fusing the metal fine particles by drying and further heat-treating in the range of 100 ° C to 300 ° C.
[0095]
In the present invention, the structure of the thin film transistor is described. In the case of a TFT sheet, the material of the signal line, the scanning line, the display electrode, the formation method, and the like when the entire TFT sheet is formed are formed in the same manner as described above. can do.
[0096]
Various insulating films can be used as the gate insulating layer of the organic thin film transistor element of the present invention, and an inorganic oxide film having a high relative dielectric constant is particularly preferable. Inorganic oxides include silicon oxide, aluminum oxide, tantalum oxide, titanium oxide, tin oxide, vanadium oxide, barium strontium titanate, barium zirconate titanate, lead zirconate titanate, lead lanthanum titanate, strontium titanate, Examples thereof include barium titanate, barium magnesium fluoride, bismuth titanate, strontium bismuth titanate, strontium bismuth tantalate, bismuth tantalate niobate, and yttrium trioxide.
[0097]
Of these, silicon oxide, aluminum oxide, tantalum oxide, and titanium oxide are preferable. Inorganic nitrides such as silicon nitride and aluminum nitride can also be suitably used.
[0098]
The insulating layer can be formed by vacuum deposition, molecular beam epitaxial growth, ion cluster beam method, low energy ion beam method, ion plating method, CVD method, sputtering method, atmospheric pressure plasma method, or other dry processes, spraying Examples include wet processes such as coating methods, spin coating methods, blade coating methods, dip coating methods, casting methods, roll coating methods, bar coating methods, die coating methods, and other methods such as printing and ink jet patterning. Can be used depending on the material. The wet process is a method of applying and drying a liquid in which fine particles of inorganic oxide are dispersed in an arbitrary organic solvent or water using a dispersion aid such as a surfactant as required, or an oxide precursor, for example, A so-called sol-gel method in which 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.
[0099]
A method for forming an insulating film by plasma film formation under atmospheric pressure will be described as follows.
[0100]
The above-mentioned plasma film-forming process under atmospheric pressure refers to a process in which a reactive gas is discharged under atmospheric pressure or a pressure near atmospheric pressure, and a reactive gas is plasma-excited to form a thin film on a substrate. JP-A-11-133205, JP-A-2000-185362, JP-A-11-61406, JP-A-2000-147209, 2000-121804, etc. (hereinafter also referred to as atmospheric pressure plasma method). Thereby, a highly functional thin film can be formed by a method with high production efficiency.
[0101]
In addition, as the organic compound film used for the insulating layer, polyimide, polyamide, polyester, polyacrylate, photo radical polymerization type, photo cation polymerization type photo curable resin, copolymer containing acrylonitrile component, polyvinyl phenol, polyvinyl alcohol , Novolak resin, cyanoethyl pullulan, and the like can also be used. As the method for forming the organic compound film, the wet process is preferable.
[0102]
Moreover, an inorganic oxide film and an organic oxide film can be laminated and used together. The thickness of these insulating films is generally 50 nm to 3 μm, preferably 100 nm to 1 μm.
[0103]
As a coating method for the composition of each layer, a known coating method 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 or the like is used. A coating method capable of continuous coating or thin film coating is preferably used.
[0104]
【Example】
EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.
[0105]
Example 1
FIG. 6 shows the configuration of the organic thin film transistor created and a part of the production process.
[0106]
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 on which an aluminum layer having a thickness of 200 nm was deposited.
[0107]
A silicon oxide film was formed thereon as the gate insulating layer 2 having a thickness of 200 nm by the atmospheric pressure plasma method. The silicon oxide film uses an apparatus described in Japanese Patent Laid-Open No. 2000-80182. As reactive gases, argon (98.2% by volume), tetramethoxysilane (0.3% by volume), hydrogen gas (1.5% (Volume%) mixed gas was used.
[0108]
Thereafter, a chloroform solution of a well-purified regioregular body of poly (3-hexylthiophene) (manufactured by Aldrich) is applied onto the silicon oxide film, and the chloroform is sufficiently dried at 150 ° C. to form an organic semiconductor having a thickness of 30 nm. Layer 3 was formed. Furthermore, a second insulating layer 4 having a thickness of 5 μm was formed by applying an ethylene glycol monomethyl ether solution of a novolak resin and treating at 120 ° C. for 10 minutes.
[0109]
Next, the second insulating layer 4 was ablated with a KrF excimer laser and processed as shown in FIG. A portion represented by oblique lines represents a laser processed surface, and a through hole T was formed on the processed surface. The width of the through hole 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 as to penetrate the second insulating layer 4 and expose the surface layer of the organic semiconductor layer.
[0110]
Next, a commercially available conductive polymer (Baytron P; Bayer P; poly- (ethylenedioxythiophene) and polystyrenesulfonic acid complex, 1% by mass of aqueous dispersion) is processed with an excimer laser using a piezo ink jet. Was discharged. FIG. 6B shows a state where ink droplets are discharged into the through holes. I is an ink droplet of a conductive polymer ejected. (The aqueous dispersion of the discharged conductive polymer does not spread on the surface of the water-repellent second insulating layer. That is, the source and drain electrodes are stably formed without short-circuiting)
Furthermore, by drying at 120 ° C. for 10 minutes, source and drain electrodes were formed to obtain an organic thin film transistor.
[0111]
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.
[0112]
(Example 2)
An organic thin film transistor was formed according to the configuration 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. The organic semiconductor layer 3 having a thickness of 30 nm is formed by applying a well-purified regioregular body (manufactured by Aldrich) of poly (3-hexylthiophene) onto the chloroform solution and thoroughly drying the chloroform at 150 ° C. Formed. Next, the organic semiconductor layer 3 and a part of the first electrode S ′ and a part of the second electrode D ′ are ablated by a KrF excimer laser, and two through holes are formed as shown in FIG. T was formed. The image of patterning the electrodes and through holes is the same as in FIG.
[0113]
Next, a gold ultrafine particle dispersion (aqueous dispersion) disclosed in Japanese Patent Application Laid-Open No. 2000-239853 is ejected onto a through hole by ink jet, dried, and heat-treated at 250 ° C. for 10 minutes to form a source electrode made of a gold thin film. S and the drain electrode D were formed. In addition, as in Example 1, a 200 nm thick silicon oxide film is formed as the gate insulating layer 2 by the atmospheric pressure plasma method, and a commercially available silver conductive paste is printed to form a 30 μm wide gate electrode G. did. A top-gate organic thin film transistor having the configuration shown in FIG. 3 was obtained.
[0114]
This organic thin film transistor showed good operating characteristics of a p-channel enhancement type FET. The carrier mobility in the saturation region was measured and found to be 0.03 cm.²/ Vs.
[0115]
(Example 3)
An organic thin film transistor was formed according to the configuration shown in FIG. On the surface of a PES film having a thickness of about 100 μm, a copper ultrafine particle dispersion (aqueous dispersion) disclosed in Japanese Patent Application Laid-Open No. 2000-239853 is ejected by ink jet, and a gap of about 30 μm is separated from the first electrode S ′. A second electrode D ′ was formed. Further, as in Example 1, a 200 nm thick silicon oxide film 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 ′ are formed by the KrF excimer laser. Then, a part of the second electrode D ′ was ablated to form two through holes T as shown in FIG.
[0116]
Next, as in Example 2, a gold ultrafine particle dispersion (aqueous dispersion) was ejected onto the through-hole T by inkjet, dried, and heat-treated at 250 ° C. for 10 minutes to form a source electrode S composed of a gold thin film. The drain electrode D was formed. At this time, the first electrode S ′ and the second electrode D ′ also exhibit conductivity by heat treatment.
[0117]
Next, a chloroform solution of a well-purified regioregular body of poly (3-hexylthiophene) (manufactured by Aldrich) is applied onto the insulating layer 4, and the chloroform is sufficiently dried at 150 ° C. Organic semiconductor layer 3 was formed. Further, an alumina film having a thickness of 300 nm was formed as the gate insulating layer 2 by an atmospheric pressure plasma method, and a commercially available silver conductive paste was printed to form a gate electrode having a width of 30 μm. A top-gate organic thin film transistor having the configuration shown in FIG. 4 was obtained.
[0118]
This organic thin film transistor showed good operating characteristics of a p-channel enhancement type FET. The carrier mobility in the saturation region was measured and found to be 0.05 cm.²/ Vs.
[0119]
  (referenceExample 4)
  A thermal oxide film having a thickness of 2000 mm was formed on an n-type Si wafer having a specific resistance of 0.01 Ω · cm, and then sublimated and purified pentacene was deposited to form an organic semiconductor layer having a thickness of 50 nm. On the organic semiconductor layer, the following composition liquid A was applied and dried using an applicator to form a photosensitive insulating layer (thickness 2 μm, light transmittance 0.5%).
[0120]
<Composition liquid A>
20 parts by mass of carbon black (trade name “MA100” manufactured by Mitsubishi Kasei Co., Ltd.) as a black pigment, and polyoxyethylene alkylphenyl ether having an HLB value of 17 as a surfactant (trade name “Neugen EA177” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) ) 5 parts by mass and 75 parts by mass of water were mixed and dispersed in 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 polymerization degree 600), 1 part by weight of p-diazodiphenylamine as a crosslinking agent, and a poly having a HLB value of 4 as a surfactant 0.1 part by mass of oxyethylene alkylphenyl ether (Daiichi Kogyo Seiyaku Co., Ltd., trade name “Neugen EA33”) was mixed to obtain Composition Liquid A.
[0121]
After irradiation with mercury lamp light through a mask, development was performed using water, and the insulating layer in the unexposed area was removed. Bayron P manufactured by Bayer, Inc .; a complex of poly- (ethylenedioxythiophene) and polystyrene sulfonic acid (aqueous dispersion 1% by mass) was discharged using a piezo ink jet and dried, and then nitrogen was removed. A heat treatment was performed at 120 ° C. for 3 minutes in a gas atmosphere to form source and drain electrodes.
[0122]
An organic thin film transistor having a channel width W = 3 mm and a channel length L = 20 μm was prepared by the above method.
[0123]
This organic thin film transistor showed good operating characteristics of a p-channel enhancement type FET when driven using a Si wafer as a gate electrode. The carrier mobility in the saturation region was measured and found to be 0.7 cm.²/ Vs.
[0124]
  (Comparative Example 1)referenceComparison of Example 4
  referenceAfter vapor-depositing gold on the pentacene vapor deposition film of Example 4, the gold was etched by photolithography to form a source electrode and a drain electrode. This element was not driven as a FET.
[0125]
(Example 5)
An aluminum film having a thickness of 300 nm and a width of 300 μm was formed on a PES (polyether sulfone) film having a thickness of 150 μm by sputtering to obtain a gate electrode material. Next, anodization was performed in a 30% by mass sulfuric acid aqueous solution for 2 minutes using a direct current supplied from a low-voltage power supply of 30 V so that the thickness of the anodized film became 120 nm. Furthermore, after performing a steam sealing treatment in a saturated steam chamber at 1 atm and 100 ° 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 poly (3-hexylthiophene) regioregular (Aldrich) was prepared, and N₂In a gas atmosphere, the silicon oxide film was coated on the surface using an applicator, dried at room temperature, and then heat-treated at 50 ° C. for 30 minutes. At this time, the film thickness of poly (3-hexylthiophene) was 50 nm. Furthermore, on the surface of the poly (3-hexylthiophene) film, the following composition liquid B was applied and dried using an applicator to form a photosensitive insulating layer (thickness 0.4 μm, light transmittance 1%). .
[0126]
<Composition liquid B>
20 parts by mass of carbon black, 5 parts by mass of polyoxyethylene alkylphenyl ether (trade name “Neugen EA177” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) having an HLB value of 17 as a surfactant, 30 parts by mass of polyvinyl alcohol and 75 parts by mass of water The mixture was mixed and dispersed with a sand mill to obtain a composition liquid B.
[0127]
Next, a semiconductor laser with an oscillation wavelength of 830 nm and an output of 100 mW is 400 mJ / cm.²When the pattern of the source electrode and the drain electrode was exposed at an energy density of 1, an exposed portion of the photosensitive insulating layer was ablated.
[0128]
An aqueous dispersion of polystyrenesulfonic acid and poly (ethylenedioxythiophene) (Baytron P manufactured by Bayer) is discharged onto the exposed portion using a piezo ink jet, dried, and then dried at 100 ° C. in a nitrogen gas atmosphere. Then, source and drain electrodes were formed. Further, a toluene dispersion of gold fine particles (average particle size of 15 nm) is discharged onto the formed source and drain electrodes using a piezo ink jet, dried, and then at 200 ° C. for 15 minutes in a nitrogen gas atmosphere. The heat treatment was performed to join the source and drain electrodes. In each electrode, a fusion layer of gold fine particles having a thickness of 300 nm is laminated on a layer having a thickness of 20 nm made of polystyrenesulfonic acid and poly (ethylenedioxythiophene).
[0129]
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.
[0130]
(Example 6)
Except that the second insulating layer was changed as follows, 20 parts by mass of carbon black, 50 g of novolak resin, and 100 g of ethylene glycol monomethyl ether were mixed and the composition liquid C dispersed in a sand mill was applied. And the 2nd insulating layer 4 of thickness 0.2micrometer was formed by processing for 10 minutes at 120 degreeC.
[0131]
This organic thin film transistor showed good operating characteristics of a p-channel enhancement type FET. The carrier mobility in the saturation region was measured and found to be 0.02 cm.²/ Vs.
[0132]
(Comparative Example 2)
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) (Bayer Baytron P) was discharged onto both ends of the polyimide film using a piezo ink jet and dried. Then, when it was dried at 100 ° C. in a nitrogen gas atmosphere, source and drain electrodes were formed.
A well-purified chloroform solution of poly (3-hexylthiophene) regioregular (Aldrich) was prepared, and N₂In a gas atmosphere, the silicon oxide film was coated on the surface using an applicator, dried at room temperature, and then heat-treated at 50 ° C. for 30 minutes. At this time, the film thickness of poly (3-hexylthiophene) was 50 nm.
[0133]
Furthermore, after providing a silicon oxide layer having a thickness of 200 nm by the atmospheric pressure plasma method described above, the above Baytron P is discharged using an ink jet and dried, and then dried at 100 ° C. in a nitrogen gas atmosphere, An electrode was formed.
The carrier mobility in the saturation region was measured and found to be 0.002 cm.²/ Vs.
[0134]
The organic thin film transistor formed according to the present invention can be formed by patterning with a simple and efficient process using coating or the like than that formed by the conventional method. Therefore, high-accuracy patterns can be formed efficiently at low cost.
[0135]
In addition, although the constituent layers such as the organic semiconductor layer are formed by a simple method such as a coating method, the accuracy of electrode pattern formation is high, so that there is little variation when the entire device is configured.
[0136]
【The invention's effect】
Organic thin film transistor with high carrier mobility, high current ON / OFF value, good switching function, and high-accuracy patterning at low cost without complicated processes, transistor characteristics in the manufacturing process The manufacturing method of the organic thin-film transistor which can suppress the fall of this was obtained.
[Brief description of the 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 illustrating a configuration example of a bottom-gate 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.
FIGS. 4A and 4B are diagrams showing a configuration example of an organic thin film transistor having a top gate type configuration and a manufacturing process thereof. FIGS.
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 the configuration and production process of an organic thin film transistor.
[Explanation of symbols]
1 Support
2 Gate insulation layer
3 Organic semiconductor layer
4 Insulation layer
G Gate electrode
S source electrode
D Drain electrode
T through hole

Claims (7)

A gate electrode is provided on the support, a gate insulating layer, an organic semiconductor layer, and a second insulating layer are sequentially formed on the gate electrode, and penetrates the second insulating layer by laser ablation so as to be in contact with the organic semiconductor layer. A method of manufacturing an organic thin film transistor, wherein two through holes are formed, and a source electrode and a drain electrode are formed so as to be bonded to the organic semiconductor layer through the through holes.   The method for producing an organic thin film transistor according to claim 1, wherein the second insulating layer is formed by water-based coating.   The method for producing an organic thin film transistor according to claim 1, wherein the second insulating layer contains a hydrophilic polymer.   A first electrode and a second electrode are provided on the support, an organic semiconductor layer is formed on the electrode, and the organic semiconductor layer is penetrated by laser ablation. The first electrode and the second electrode 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, the first electrode, and the second electrode through the through holes, and the source A method for producing 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.   A first electrode and a second electrode are provided on a support, an insulating layer is formed thereon, and at least the insulating layer is penetrated by laser ablation to thereby form a first electrode and a second electrode, respectively. After forming two through holes in contact with each other, a source electrode and a drain electrode are formed so as to be joined to the first electrode and the second electrode through the through holes, and the source electrode and the drain electrode are formed on the source electrode and the drain electrode. In addition, an organic semiconductor layer and a gate insulating layer are sequentially formed, and a gate electrode is provided on the gate insulating layer.   A first electrode and a second electrode are provided on the support, an insulating layer and an organic semiconductor layer are sequentially formed thereon, and at least the insulating layer and the organic semiconductor layer are penetrated by laser ablation. After providing two through holes in contact with one electrode and the second electrode, the source electrode and the drain are connected to the organic semiconductor layer, the first electrode, and the second electrode through the through holes, respectively. An organic thin film transistor manufacturing method comprising: forming an electrode; forming a gate insulating layer on the source electrode and the drain electrode; and attaching a gate electrode on the gate insulating layer. The electrode material solution or dispersion, using an inkjet, the Suruho and discharge Le, according to any one of claims 1 to 6, characterized in that to form the source electrode and the drain electrode patterned Manufacturing method of organic thin film transistor.

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