TWI664758B - Method for forming organic semiconductor film, organic semiconductor using said method and method for fabricating the same - Google Patents

Abstract

The present invention provides a method for forming an organic semiconductor thin film capable of forming an organic semiconductor thin film in a short time, and provides an organic semiconductor device to which the organic semiconductor thin film is applied, and a method for manufacturing an organic semiconductor device with a high throughput. In the method for forming an organic semiconductor thin film (4) composed of an organic semiconductor material (7), ultrasonic vibration is applied to the organic semiconductor material (7) while applying pressure to thin the organic semiconductor material (7). The manufacturing method of an organic semiconductor device is a manufacturing method of an organic semiconductor device including an organic semiconductor thin film, and the organic semiconductor thin film is formed by the above-mentioned forming method. The organic semiconductor device is manufactured by the above-mentioned manufacturing method.

Description

Forming method of organic semiconductor thin film, and organic semiconductor device using the method and manufacturing method thereof

The present invention relates to a method for forming an organic semiconductor thin film, an organic semiconductor device using the same, and a method for manufacturing an organic semiconductor device using the same.

A method of forming a thin film of an organic semiconductor material between electrodes to obtain an organic semiconductor device. Since it can be manufactured at a low temperature and can be made more flexible, lightweight, and less likely to be damaged, this research has been actively conducted in recent years. .

However, most of the organic semiconductor materials used in organic semiconductor devices have been difficult to dissolve in organic solvents. Therefore, it is not possible to form the thin film by cheap methods such as coating or printing. Generally, the cost is higher by vacuum evaporation. This thin film is formed on a substrate by a plating method or the like. Recently, studies on forming an organic semiconductor thin film by a coating or printing method using inkjet, flexographic printing, coating, etc., and obtaining an organic semiconductor device have been conducted. Actively, organic semiconductor devices having relatively high carrier mobility (hereinafter referred to as "mobility" as appropriate) are gradually available. The above-mentioned method using coating or printing is expected to produce a large-area field-effect transistor at a low cost and a high throughput in the manufacturing process of the field-effect transistor.

However, a field effect transistor using an organic semiconductor with a high mobility and excellent durability using a coating process or a printing process has not yet been put into practical use. Generally, an organic semiconductor thin film is formed by a vacuum process including a vacuum evaporation method or a coating process such as spin coating or doctor blade coating using a solvent. However, a method for forming an organic semiconductor thin film according to a vacuum process, in addition to having a device for performing a vacuum process, also has the disadvantage that the loss of the organic semiconductor material is large. The formation method of the organic semiconductor thin film according to the coating process, because the organic semiconductor solution is applied to the entire substrate, is the same as the vacuum process, and also has the disadvantage that the loss of the organic semiconductor material is large.

As another method for forming an organic semiconductor thin film, a printing method such as an inkjet method is known. The printing method can apply the necessary amount of organic semiconductor material to the target position. However, like other coating or printing methods, in order to control the orientation direction of the crystals generated from the solution, the temperature, ambient gas, and coating surface must be treated. For precise process control, the organic semiconductor thin film is formed slowly, or sintering must be performed for several minutes to several tens of minutes for crystal growth after crystal formation. Therefore, in these organic semiconductor thin film formation methods based on a coating or printing method, film formation of an organic semiconductor thin film or sintering for crystal growth takes time, and there is a disadvantage that the throughput is not high. In addition, according to coating or printing A method of manufacturing an organic semiconductor device by a conventional organic semiconductor thin film forming method such as a brush method has not yet reached practicality regarding the performance of organic semiconductor devices such as mobility.

One of the reasons why the manufacturing method of an organic semiconductor device by a conventional organic semiconductor thin film forming method, such as a coating or printing method, has not yet reached practicality, can be enumerated by the grain boundaries or molecular alignment between the polycrystals of organic semiconductor materials. Depending on the state of the organic semiconductor thin film such as the control, the characteristics of the organic semiconductor device such as the organic thin film transistor will greatly change.

A method for forming a single-crystal organic semiconductor thin film having no crystal grain boundaries can be shown: a method for forming a single-crystal organic semiconductor thin film by a gas phase method (physical vapor phase growth) described in Non-Patent Document 1; a patent A method of tilting a substrate and forming droplets of an organic semiconductor solution on the substrate described in Document 1 to evaporate the solvent and grow crystals from the organic semiconductor solution in a certain direction (inclined direction); described in Patent Document 2 A method for producing a single-crystalline organic semiconductor thin film by a double inkjet method.

However, the method for forming an organic semiconductor thin film by the gas phase method described in Non-Patent Document 1 is still difficult to apply to the manufacture of an actual organic semiconductor device. In addition, the method of tilting the substrate in the solution method described in Patent Document 1 is extremely difficult to tilt the substrate itself. In addition, in the method for producing an organic semiconductor thin film according to the dual inkjet method described in Patent Document 2, it is difficult to select a solvent and control the drying property. This result will result in the use of solvents that have a negative impact on the environment. Or a problem that a method for manufacturing an organic semiconductor thin film having a high throughput cannot be realized.

In addition, a method for aligning crystals other than a single crystal of an organic semiconductor is disclosed in Patent Document 3, for example, a method in which a liquid crystal organic semiconductor material is applied to an alignment film and crystals are aligned using liquid crystal transfer. However, in the above method, cracks may be formed between crystals due to a phase change in the cooling process, and the temperature in the cooling process must be precisely controlled.

Non-Patent Document 2 describes a method for promoting re-alignment of crystals by forming a polycrystalline organic semiconductor thin film and then exposing it to a solvent vapor. However, in the above method, in order to reorient the crystals, it is necessary to expose the crystallized organic semiconductor thin film to a solvent for a long time, and it is not suitable to be applied to a method for manufacturing a high-volume organic semiconductor.

On the other hand, a known processing technique for thermoplastic resins is ultrasonic welding. Ultrasonic welding is known to be a joining technology that uses frictional heat generated by ultrasonic vibration and pressure, and a processing technology that has a short processing time. Ultrasonic welding is mainly used in many fields such as spot welding, sealing of films, sealing of non-woven fabrics, and embedding of metals. However, a technique for thinning an organic semiconductor material by ultrasonic vibration and pressure is not yet known.

An example of using an ultrasonic wave for the formation of an organic semiconductor thin film is disclosed in Patent Document 4 in which a ultrasonic wave is irradiated onto a coating film containing an organic semiconductor material or the like as a main component. However, the method described in Patent Document 4 is a technique for modifying the coating film and reducing the resistance by irradiating ultrasonic waves onto the coating film. Therefore, the ultrasonic wave in Patent Document 4 Irradiation is only a replacement of the thermal sintering process or drying process performed by a general oven or the like after the formation of the organic semiconductor thin film, rather than the formation of the organic semiconductor thin film in a short time by ultrasonic irradiation and pressure .

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese International Publication No. 2011/040155

[Patent Document 2] Japanese Patent Laid-Open No. 2012-49291

[Patent Document 3] Japanese Patent No. 4867168

[Patent Document 4] Japanese Patent Laid-Open No. 2013-74065

[Non-patent literature]

[Non-Patent Literature 1] Science and Technology of Advanced Materials, 2009, 10, 024314

[Non-Patent Document 2] APPLIED PHYSICS LETTERS, 94, 093307, 2009

An object of the present invention is to provide a method for forming an organic semiconductor thin film capable of forming an organic semiconductor thin film by a short time process, and to provide an organic semiconductor device using the above organic semiconductor thin film, and a method for manufacturing an organic semiconductor device with a high throughput.

The present inventors have conducted intensive studies in order to solve the above-mentioned problems. As a result, they have found that a method for forming an organic semiconductor film that applies ultrasonic vibration while applying pressure to the organic semiconductor material to thin the organic semiconductor material can be processed in a short time An organic semiconductor thin film, and an organic semiconductor device using an organic semiconductor thin film with a high throughput can be manufactured with a high throughput by using the formation method of the organic semiconductor thin film, thus completing the present invention.

That is, the method for forming an organic semiconductor thin film of the present invention is a method for forming an organic semiconductor thin film composed of an organic semiconductor material, and is characterized in that ultrasonic pressure is applied to the organic semiconductor material while applying pressure to the organic semiconductor. Thin material.

The method for manufacturing an organic semiconductor device according to the present invention is a method for manufacturing an organic semiconductor device including an organic semiconductor thin film, and is characterized in that the organic semiconductor thin film is formed by the method for forming an organic semiconductor thin film according to the present invention.

The organic semiconductor device of the present invention is characterized by being manufactured by the above-mentioned manufacturing method.

According to the present invention, it is possible to provide a method for forming an organic semiconductor thin film capable of forming an organic semiconductor thin film in a short time, an organic semiconductor device using the organic semiconductor thin film, and a method for manufacturing an organic semiconductor device with a high throughput.

1.1'‧‧‧ substrate

2‧‧‧Gate electrode

3'‧‧‧ Gate insulation layer (insulation layer)

4‧‧‧Semiconductor layer (organic semiconductor film)

5‧‧‧Source electrode

6‧‧‧ Drain electrode

7‧‧‧Organic semiconductor materials

8‧‧‧source-drain substrate

9‧‧‧ Gate substrate

10A‧‧‧Organic thin film transistor (organic semiconductor device)

10B‧‧‧Organic thin film transistor

20‧‧‧ Ultrasonic Welding Machine

21‧‧‧ Ultrasonic Oscillator

22‧‧‧Ultrasonic vibration parts

23‧‧‧ Amplifier

24‧‧‧ Welding head

25‧‧‧Pressure mechanism

26‧‧‧Heating platform

26a‧‧‧heater

FIG. 1 is a schematic diagram showing a configuration of an ultrasonic fusion machine used in a method for forming an organic semiconductor thin film according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a step of a manufacturing method for manufacturing a common example of an organic semiconductor device of the present invention, and shows that an organic semiconductor material is sandwiched between a source-drain substrate and a gate substrate. This is a schematic diagram of the state of the step (the state at the end of the step) of the step set on the heating stand of the ultrasonic fusion machine.

FIG. 3 is a schematic diagram showing another step of the manufacturing method for manufacturing the same example of the organic semiconductor device of the present invention, and shows the step of lowering the welding head of the ultrasonic fusion machine to apply pressure to the organic semiconductor material. The schematic diagram.

FIG. 4 is a schematic diagram showing another step of the manufacturing method for manufacturing the same example of the organic semiconductor device of the present invention, and shows that ultrasonic vibration is applied to the organic material in a state where pressure is applied to the organic semiconductor material. A schematic view of a step of heating an organic semiconductor material using a semiconductor material.

FIG. 5 is a schematic diagram showing another step of the manufacturing method for manufacturing the same example of the organic semiconductor device of the present invention, and shows a schematic diagram of the step of ending the application of ultrasonic vibration to the organic semiconductor material to form an organic semiconductor thin film. .

FIG. 6 is a schematic diagram showing another step of the manufacturing method for manufacturing the same example of the organic semiconductor device of the present invention, and shows a schematic diagram of the steps for obtaining the organic semiconductor device by raising the welding head of the ultrasonic fusion machine. .

Figures 7 (a) and (b) are schematic views showing an example of a structure example of an organic thin film transistor as an example of the organic semiconductor device of the present invention.

FIG. 8 is a graph showing a temperature history of an organic semiconductor material in a method of forming an organic semiconductor thin film according to an example of the implementation of the present invention.

FIG. 9 is a polarizing microscope photograph of an organic semiconductor material at a point in time when the organic semiconductor material is arranged on a heating stage in an embodiment of the present invention.

FIG. 10 is a polarizing microscope photograph of an organic semiconductor material after the organic semiconductor material is heated by a heating stand at 100 ° C. in an embodiment of the present invention.

FIG. 11 is a polarizing microscope photograph of an organic semiconductor thin film formed by a method for forming an organic semiconductor thin film according to an embodiment of the present invention.

FIG. 12 is a polarizing microscope photograph of an organic semiconductor material at a point in time when the organic semiconductor material is arranged on a heating stand in another embodiment of the present invention.

FIG. 13 is a polarizing microscope photograph of an organic semiconductor thin film formed by a method for forming an organic semiconductor thin film according to another embodiment of the present invention.

FIG. 14 is a polarizing microscope photograph of an organic semiconductor material at a point in time when the organic semiconductor material is arranged on a heating stage in another embodiment of the present invention.

FIG. 15 is a polarizing microscope photograph of an organic semiconductor thin film formed by a method for forming an organic semiconductor thin film according to another embodiment of the present invention.

The present invention is explained in detail below.

A first object of the present invention is to provide a method for forming an organic semiconductor thin film capable of forming an organic semiconductor thin film in a short time.

The method for forming an organic semiconductor thin film according to the present invention is characterized in that ultrasonic vibration is applied while applying pressure to an organic semiconductor material, so that the organic semiconductor material is formed into a thin film to form an organic semiconductor film composed of an organic semiconductor material. According to the above method, an organic semiconductor thin film can be formed by a short-time process. In addition, in the above method, when pressure is applied to the organic semiconductor material during the cooling process after the end of the ultrasonic vibration, the organic semiconductor film is less likely to be cracked by a phase change or the like during the cooling process.

In the process of applying ultrasonic vibration while applying pressure to an organic semiconductor material, the organic semiconductor material may be used alone as the object to be treated, but a material obtained by disposing the organic semiconductor material on a substrate as the object to be treated is applied to the substrate. The organic semiconductor material is more preferably subjected to the above treatment. In the method of the present invention, it can be considered that by applying the above treatment to the organic semiconductor material on the substrate, the reorientation of the crystal is caused and the orientation of the crystal is uniformized. Therefore, when the organic semiconductor material is arranged on the substrate, It is not necessary to perform a re-alignment process for crystallization (such as a sintering process after the configuration of the organic semiconductor material by a solution process). In addition, when an organic semiconductor material is disposed on a substrate, even if the position of the organic semiconductor material is from a desired position where an organic semiconductor thin film is to be formed (for example, when manufacturing an organic thin film transistor, a source electrode and a drain electrode on the substrate are formed). between (Position) is slightly deviated, and the organic semiconductor material can be pressed and extended to the surface direction of the substrate by the above-mentioned process, so the organic semiconductor thin film can be formed at a desired position. Therefore, the arrangement of organic semiconductor materials is not required to be highly accurate.

A process for imparting ultrasonic vibration while applying pressure to an organic semiconductor material. More preferably, the organic semiconductor material is sandwiched between a pair of substrates as the object to be treated, and the sandwiched between the pair of substrates. The organic semiconductor material is subjected to the above treatment. Thereby, during the above-mentioned treatment, the organic semiconductor material can be prevented from being attached to the welding head or the pedestal of the ultrasonic welding device, and the organic semiconductor thin film can be prevented from cracking by the phase change during the cooling process. Examples of the substrate include inorganic substrates such as glass and various resin films as examples of the substrates 1 and 1 'constituting the organic thin-film transistors 10A and 10B at a later stage, and formation of electrodes and / or insulating layers. Above these and so on. The aforementioned one pair of substrates is preferably a resin film.

When the organic semiconductor material is arranged on the substrate, the organic semiconductor material can be arranged on the substrate in a solid state or a molten state. In addition, the method of disposing the organic semiconductor material on the substrate in a solid state or a molten state has advantages such that the organic semiconductor material can be disposed on the substrate without using an organic solvent having a high environmental load. The method of disposing the organic semiconductor material on the substrate in a solid state or a molten state can be used: a method of directly disposing a solid organic semiconductor material such as a block powder, a fine powder, etc. on the substrate; A solid organic semiconductor material such as a fine powder is placed on a member such as a metal rod after being sufficiently heated and melted, and then the organic semiconductor material in a molten state is removed from the member. Method of dripping onto a substrate, etc.

The method of disposing the organic semiconductor material on the substrate may be a solution process such as a drop casting method (for example, a step of coating or printing a solution in which the organic semiconductor material is dissolved in an organic solvent), and a drying step. Composition). In the method for forming an organic semiconductor thin film of the present invention, ultrasonic vibration is applied while applying pressure to an organic semiconductor material, thereby generating frictional heat to raise the temperature of the organic semiconductor material. After the application of the ultrasonic vibration is ended, the organic semiconductor material is cooled. During this cooling process, the reorientation of the crystals of the organic semiconductor material can be considered to make the orientation of the crystals uniform. Therefore, when the organic semiconductor material is arranged on the substrate using a solution process, the orientation of the crystals may be disordered in the stage where the organic semiconductor material is crystallized from the organic solvent solution containing the organic semiconductor material. Therefore, in the method for forming an organic semiconductor thin film of the present invention, in a solution process for disposing an organic semiconductor material on a substrate, after coating or printing a solution in which the organic semiconductor material is dissolved in an organic solvent, Only the organic solvent contained in the solution was evaporated. Therefore, after coating or printing a solution obtained by dissolving an organic semiconductor material in an organic solvent, it is not necessary to perform crystallization alignment control or post-processing by long-term baking in order to make the orientation of crystals uniform. Crystallization process of re-alignment. The organic semiconductor material arranged on the substrate in this manner is formed into a thin film by applying ultrasonic vibration while applying pressure to the organic semiconductor material to form an organic semiconductor thin film.

The method of applying pressure to the organic semiconductor material is not particularly limited, and it is preferable to press the pressing member directly or through a protective film or a protective layer. Resistant to organic semiconductor materials. When the protective film or protective layer presses the pressure member against the organic semiconductor material, it is particularly preferable to use the organic semiconductor material sandwiched between the substrate and the protective film or protective layer as the object to be treated, and pass through the protective film. Or the protective layer presses the pressing member against the organic semiconductor material on the substrate. In addition, the method of applying ultrasonic vibration while applying pressure to the organic semiconductor material is not particularly limited, but the organic semiconductor material is placed on the substrate and the pressure member is pressed against the organic material directly or through a protective film or layer. As the semiconductor material, a method of subjecting the pressure member to ultrasonic vibration is preferred. The pressure member is not particularly limited as long as it can apply pressure to the entire organic semiconductor material, and when the base material is a flat plate, the surface of the pressure member that abuts against the organic semiconductor material is preferably a flat surface. Thereby, an organic semiconductor thin film having a uniform thickness can be formed. The above-mentioned protective film or protective layer will be described later.

The method for forming the organic semiconductor thin film of the present invention includes a method using a general ultrasonic welding machine (ultrasonic welding machine) used for compression bonding of a packaging film or the like. When using a general ultrasonic fusion splicer, the organic semiconductor material is used as the object to be treated (separate organic semiconductor material, combination of organic semiconductor material and substrate, combination of organic semiconductor material and protective film or protective layer, or organic semiconductor material and The combination of the base material and the protective film or protective layer), the ultrasonic welding machine is used to apply ultrasonic vibration while applying pressure to the organic semiconductor material, and the frictional heat and pressure generated by the ultrasonic vibration are used to make the organic The semiconductor material is thinned to form the organic semiconductor thin film of the present invention. A general ultrasonic welding machine is provided with an ultrasonic pressure while being pressed against the object to be processed, while applying pressure to the object to be processed. The oscillating welding head is used as a pressure member.

Hereinafter, an embodiment of an ultrasonic welding machine that can be preferably used in the method for forming an organic semiconductor thin film of the present invention will be described with reference to FIG. 1. Components having the same function in each figure are denoted by the same reference numerals and descriptions thereof are omitted.

The ultrasonic welding machine 20 includes, as shown in Fig. 1, an ultrasonic oscillator (generator) 21, an ultrasonic vibrator (converter) 22, an amplifier 23, a welding head 24, and a pressurizing mechanism (molding unit). 25, and the heating base 26. The horn 24 is flat on the surface abutting the object to be processed.

The heating base 26 is a person on which an object to be processed is arranged. The heating pedestal 26 includes a heater 26 a for heating the upper surface of the heating pedestal 26 to a predetermined temperature. The upper surface of the heating base 26 may not be heated. Therefore, instead of the heating stand 26, a simple stand without the heater 26a may be used.

The pressurizing mechanism 25 includes: an arm portion 25a to which the ultrasonic vibrator 22, the amplifier 23, and the welding head 24 are mounted; a pillar 25b that allows the arm portion 25a to be slidably supported vertically and vertically; and an arm portion 25a A drive mechanism (not shown) (for example, an air cylinder) that moves up and down in the vertical direction and presses the welding head 24 downward in the vertical direction to apply pressure on the object to be processed disposed on the heating base 26.

In the ultrasonic fusion splicer 20, the ultrasonic signal 21 is used to increase the electrical signal input from a commercial power source (not shown) to a high-frequency electrical signal, and the ultrasonic vibration element 22 is used to increase the electrical signal. The sexual signal is converted into mechanical vibration energy, and mechanical vibration is emitted from the ultrasonic vibration member 22 (ultrasonic Wave vibration). The mechanical vibration (ultrasonic vibration) emitted from the ultrasonic vibration element 22 is transmitted to the welding head 24 by the amplitude of the amplitude increaser 23. The ultrasonic vibration transmitted to the welding head 24 is transmitted to the object including the organic semiconductor material when the welding head 24 is pressed downward in a vertical direction by the pressurizing mechanism 25 to apply pressure.

The parameters controlled when applying ultrasonic vibration while applying pressure to the organic semiconductor material are mainly exemplified by the oscillation time of ultrasonic vibration, the amplitude of ultrasonic vibration, the pressure, and the shape of the welding head of the ultrasonic fusion machine (using For ultrasonic welding machines with welding heads). The oscillation time of the ultrasonic vibration is the time that the ultrasonic vibration is imparted to the organic semiconductor material. The longer the time, the greater the amount of heat applied to the organic semiconductor material, but it must be appropriately adjusted in accordance with the physical properties of the organic semiconductor material. In addition, if the processing time of the organic semiconductor thin film formation process is considered, it is preferable to perform appropriate processing in a short time, and it is generally set to be within 1 minute, preferably within 10 seconds, and particularly preferably within 1 second. .

The amplitude of the ultrasonic vibration indicates the magnitude of the ultrasonic vibration imparted to the organic semiconductor material (the size of the ultrasonic vibration transmitted from the tip of the welding head to the organic semiconductor material when using an ultrasonic welding machine with a welding head). When using an ultrasonic welding machine, even if an ultrasonic welding machine with the same output is used, the heat applied to the organic semiconductor material can be changed by changing the amplitude of the ultrasonic vibration. The higher the amplitude of the ultrasonic vibration, the more heat can be given to organic semiconductor materials. However, when using organic semiconductor materials in combination with other materials such as substrates, it is necessary to consider the damage caused to other materials such as substrates at the same time. , Set so that the amplitude of the ultrasonic vibration is not excessive high. The amplitude of the ultrasonic vibration is changed by the output of the ultrasonic fusion machine (when using the ultrasonic fusion machine), the number of vibrations (frequency) of the ultrasonic vibration, and the like to change the appropriate amplitude. Therefore, it is necessary to control the proper amplitude according to the type of the organic semiconductor material used and the type of the member to which frictional heat is applied when ultrasonic vibration is given in combination with the organic semiconductor material as necessary. The members to which the frictional heat is applied when the ultrasonic vibration is imparted include, for example, a substrate, an electrode (gate electrode, source electrode, drain electrode, etc.), an insulating layer (such as a gate insulating layer), and a thin film transistor protection. Layer, a member (a protective film or a protective layer, etc.) that presses a pressure member such as a welding head against an organic semiconductor material through other members to give contact with a pressure member such as a welding head when giving ultrasonic vibration. That is, in the method for forming an organic semiconductor thin film of the present invention, it is preferable that the amplitude of the ultrasonic vibration is controlled to an appropriate amplitude so that the temperature of the organic semiconductor material is controlled to an appropriate temperature.

The applied pressure is the mechanical energy imparted to the processed object containing the organic semiconductor material (the mechanical energy transmitted from the welding head to the organic semiconductor material when using an ultrasonic welding machine with a welding head), and its magnitude is the same as that caused by ultrasonic vibration. The heat generated in the organic semiconductor material is related to the processing time (the time required for the organic semiconductor material to be thinned). If an excessively strong pressure is applied to a processed object containing an organic semiconductor material, the same as when the amplitude of the ultrasonic vibration is too large, the organic semiconductor material may be damaged. In addition, the organic semiconductor material and other materials such as the substrate may be damaged. When used in combination, it may cause damage to other materials such as substrates. Therefore, the pressure must be set in such a way that the damage is not excessive. These parameters (oscillation time of ultrasonic vibration, amplitude of ultrasonic vibration, and pressure) are mutually influential. It is necessary to appropriately combine the type of the organic semiconductor material used and the type of the member to which frictional heat is applied when the ultrasonic vibration is applied in combination with the organic semiconductor material as necessary.

The shape of the welding head of the ultrasonic welding machine must have a proper structure in order to transmit the transmitted ultrasonic vibration to the organic semiconductor material. The amplitude of the ultrasonic vibration may change depending on the shape. In addition, the amount of heat applied to the organic semiconductor material also changes according to the size (processing area) of the surface of the welding head, so the shape of the welding head and the size of the surface of the welding head must be individually controlled.

The temperature of the organic semiconductor material at the time of applying ultrasonic vibration while applying pressure to the organic semiconductor material (hereinafter, appropriately referred to as "pressurization and ultrasonic vibration application") is set depending on the type of the organic semiconductor material. When the organic semiconductor material has a phase transition point (phase transition temperature), it is preferable that the temperature of the organic semiconductor material at the time of applying pressure and ultrasonic vibration is adjusted to 0 to + 80 ° C relative to the phase transition point of the organic semiconductor material. Within range. In addition, when an organic semiconductor material is used in combination with a substrate, the temperature of the organic semiconductor material when applying pressure and ultrasonic vibration is preferably set below the glass transition point (glass transition temperature of the substrate used). ), And the combination of the phase transition point of the organic semiconductor material and the glass transition point of the substrate to set the optimum temperature range of the temperature of the organic semiconductor material when applying pressure and ultrasonic vibration. Here, the "temperature of the organic semiconductor material at the time of applying pressure and ultrasonic vibration" means a heat-conducting sheet at the time of applying pressure and ultrasonic vibration to the organic semiconductor material instead of the organic semiconductor material as in the measurement method of the example. temperature.

In addition, the organic semiconductor material may also be subjected to conduction heating while applying ultrasonic vibration to the organic semiconductor material. When an organic semiconductor material is used in combination with a substrate, it is also possible to assist in conducting conduction heating of the substrate while giving ultrasonic vibration as needed. At this time, the heating temperature of the base material may be changed as needed, as long as the heating temperature of the organic semiconductor material at the time of application of pressure and ultrasonic vibration is applied. However, in order to avoid deformation of the base material or damage to other members, When using the base material and other components in combination, set it as low as possible.

In order to thin the organic semiconductor material, the temperature of the organic semiconductor material at the time of application of pressure and ultrasonic vibration is preferably a temperature exceeding the phase transition point (ie, the liquid crystal transition point, glass transition point, melting point, etc.) of the organic semiconductor material. . At this time, under these conditions, when the organic semiconductor material is subjected to pressure and ultrasonic vibration, it is transferred from the solid phase (phase change) to the liquid crystal phase, glass phase, liquid phase, etc., and has fluidity. The applied pressure forms a thin film. At this time, during the cooling process after the end of the application of the ultrasonic vibration, the organic semiconductor material is recrystallized to obtain an organic semiconductor thin film. That is, in the method for forming an organic semiconductor thin film of the present invention, after applying pressure to the organic semiconductor material while applying ultrasonic vibration to transfer the phase of the solid organic semiconductor material, it is preferable to recrystallize the organic semiconductor material and Thinning the organic semiconductor material. Thereby, since the organic semiconductor material phase of the solid phase is transferred to improve the fluidity of the organic semiconductor material, it is easy to make the organic semiconductor material into a thin film. During the application of pressure and ultrasonic vibration, even if the phase transition of the organic semiconductor material is not caused, the organic semiconductor material can be subjected to sufficient pressure while being heated by ultrasonic vibration. Force to cause filming.

After the application of pressure to the organic semiconductor material starts to provide ultrasonic vibration, if the application of ultrasonic vibration is ended, the temperature of the organic semiconductor material will decrease sharply, causing reorientation and recrystallization of the organic semiconductor material. After the application of ultrasonic vibration is completed, in order to obtain a uniform organic semiconductor film in the thickness direction, the organic semiconductor material can be continuously pressurized. The time for which the pressure is continuously applied after the end of ultrasonic vibration application is preferred. Maximum reaching temperature of the organic semiconductor material at the time of applying pressure and ultrasonic vibration, the temperature difference between the temperature of the organic semiconductor material at the end of the ultrasonic vibration application (after cooling) and the room temperature, and the surface energy of the substrate (the organic semiconductor Material and substrate). Compared with the organic semiconductor thin film obtained by a general solution process, the organic semiconductor thin film obtained in this way is less prone to cracks between crystal grains.

When using an ultrasonic welding machine equipped with a welding head to apply pressure and ultrasonic vibration, in order to prevent the welding head from directly contacting the semiconductor material, a protective film or a protective layer may be provided on the organic semiconductor material and passed through the protective film or The protective layer presses the welding head against the organic semiconductor material. When a protective film or protective layer is provided on an organic semiconductor material formed on a substrate, the protective film or protective layer used here may be the same as or different from the substrate. In addition, after forming the organic semiconductor film, in order to peel off the protective layer, a film with a protective layer may be laminated on the release material, and the release material may be placed on the organic semiconductor material in such a manner that the release material contacts the organic semiconductor material.

The liquid crystal transition point, glass transition point, and melting point of organic semiconductor materials can be measured by differential scanning thermal analysis (DSC: Differential). Scanning Calorimetry), Polarized Optical Microscope (POM) observation, automatic melting point measurement device, etc., to grasp the phase transfer operation and measure. In addition, regarding the high-order structure of the organic semiconductor material, X-ray diffraction (XRD: X-ray Diffraction) can be used to grasp the relationship between the molecular structure, liquid crystallinity, and crystallinity of the organic semiconductor material.

As organic semiconductor materials, low-molecular organic compounds (low-molecular organic semiconductor compounds) exhibiting semiconductor characteristics, and high-molecular organic compounds (high-molecular organic semiconductor compounds) exhibiting semiconductor characteristics (especially polymers having a number average molecular weight of 1,000 or more) Compounds) and oligomers (oligomer organic semiconductor compounds) having a repeating unit of 2 to 20 showing semiconductor characteristics can be used. Among the organic semiconductor materials, an organic semiconductor material having a phase transition point such as a liquid crystal transition point, a glass transition point, a melting point, or the like at a temperature below the highest reaching temperature at the time of application of pressure and ultrasonic vibration is preferred. In addition, when an organic semiconductor material is used in combination with a substrate having a glass transition point (especially a resin substrate such as a resin film), the organic semiconductor material preferably has a phase transition point lower than the glass transition point of the substrate, especially The best system has a phase transition point below the maximum temperature reached when pressure and ultrasonic vibration are applied, and lower than the glass transition point of the substrate. When an organic semiconductor material and a resin substrate are used in combination, the phase transition point of the organic semiconductor material is preferably in a range of 70 to 280 ° C, and the phase transition point of the organic semiconductor material is more preferably in a range of 100 to 280 ° C.

In the method for forming an organic semiconductor thin film of the present invention, one of the characteristics is that the crystal reorientation of the organic semiconductor material can be considered to make the orientation of the crystal uniform. Therefore, among these organic semiconductor materials, In particular, when an organic semiconductor material having crystallinity is used, an organic semiconductor device having excellent semiconductor characteristics such as mobility can be easily obtained in a short time.

Examples of the low-molecular-weight organic semiconductor compound include polyacene (polyacene), a part of carbon atoms of polyacene, and a polyvalent functional group such as a nitrogen atom, a sulfur atom, an oxygen atom, or a carbonyl group. Or derivatives in which a part of hydrogen atoms of polyacene are substituted with monovalent functional groups such as aryl, fluorenyl, alkyl, and alkoxy groups (triphenodioxazine derivatives, triphenyldithiazine Triphenodithiazine derivatives, and Thienothiophene derivatives represented by the general formula (1) described later). In addition to the above-mentioned low-molecular organic semiconductor compounds, styrene benzene derivatives, metal phthalocyanines, condensed cyclotetracarboxylic acid diamidines, merocyanine pigments, or Pigments such as hemicyanine pigments, charge transfer complexes typified by tetrakis (octadecylsulfide) tetrathiafulvalene, and the like. Examples of the condensed cyclic tetracarboxylic acid diamidoimides include naphthalene-1,4,5,8-tetracarboxylic acid diamidoimine, N, N'-bis (4-trifluoromethylbenzyl) naphthalene- 1,4,5,8-tetracarboxylic acid diamidoimine, N, N'-bis (1H, 1H-perfluorooctyl) -1,4,5,8-tetracarboxylic acid diamidoimine, N , N'-bis (1H, 1H-perfluorobutyl) -1,4,5,8-tetracarboxylic acid diamidoimine, N, N'-dioctylnaphthalene-1,4,5,8- Naphthalenetetracarboxylic acid dihydrazones such as tetracarboxylic acid dihydramine, naphthalene-2,3,6,7-tetracarboxylic acid dihydrazone; anthracene-2,3,6,7-tetracarboxylic acid Anthracene tetracarboxylic acid diamidine and the like.

Examples of the polymer organic semiconductor compound include polypyrroles such as polypyrrole, poly (N-substituted pyrrole), poly (3-substituted pyrrole), and poly (3,4-disubstituted pyrrole); polythiophene, poly (3-substituted thiophene), poly Polythiophenes such as (3,4-disubstituted thiophenes) and polybenzothiophenes; Polyisothioindines such as Polyisothianaphthene; Polythiophenes such as Thienylene Vinylene; Poly (P-styrene) and other poly (p-styrene); polyaniline, poly (N-substituted aniline), poly (3-substituted aniline), poly (2,3-disubstituted aniline) and other polyanilines; Polyacetylenes such as polyacetylene; Polydiacetylenes such as polydiacetylene; Polyfluorenes such as Polyazulene; Polyfluorenes such as Polypyrene; Polycarbazole, Poly (N-substituted Carbazoles, etc .; polyselenophenes, etc .; polyfurans, polyfurans, polybenzofurans, etc .; poly (p-benzenes), etc. Polyindoles such as polyindole; polypyridazines such as polypyridazine; polysulfides such as polyphenylene sulfide and polyethylene sulfide.

The oligomer organic semiconductor compound is an oligomer having the same repeating unit as the polymer, and examples thereof include α-hexathiophene of thiophene hexamer, α, ω-dihexyl-α-hexathiophene, α Oligomers such as, ω-dihexyl-α-pentathiophene, α, ω-bis (3-butoxypropyl) -α-hexathiophene.

As an example of an organic semiconductor material which is particularly preferable in the practice of the present invention, a thienothiophene derivative represented by the following general formula (1) may be mentioned, (In the above formula, R ₁ and R ₂ each independently represent a hydrogen atom, an alkyl group, an aryl group which may have a substituent, a heterocyclic group which may have a substituent, an alkoxy group, an alkoxyalkyl group, R ₁ and R ₂ may be the same or different from each other, and m and n each independently represent 0 or 1).

The alkyl group is a linear, branched or cyclic aliphatic hydrocarbon group, preferably a linear or branched aliphatic hydrocarbon group, and particularly preferably a linear aliphatic hydrocarbon group. The carbon number of the alkyl group is usually 1 to 36, preferably 2 to 24, particularly preferably 4 to 20, and more preferably 6 to 12.

The aryl group is phenyl, biphenyl, fluorenyl, xylyl, xylylmethyl, cumyl, benzyl, phenylethyl, α-methylbenzyl, triphenylmethyl, benzene Aromatic hydrocarbon groups such as vinyl, cinnamyl, biphenyl, 1-naphthyl, 2-naphthyl, anthracenyl, and phenanthryl. The heterocyclic group is a 2-phenyl group, a benzophenyl group, a thienylphenyl group, and the like. These aryl groups and heterocyclic groups may each have a substituent such as the above-mentioned alkyl group. When there are a plurality of substituents, the plurality of substituents may be the same or different.

In order that the thienothiophene derivative represented by the general formula (1) has a phase transfer point in the above range (70 ° C to 280 ° C), it is preferred that at least one of R ₁ and R ₂ is an alkyl group, and the alkane The length of the base chain is preferably 4 or more.

The thienothiophene derivative represented by the general formula (1) can be obtained by Journal of the American Chemical Socciety, 2007, Vol. 129, No. 51, p. 15732-15733, and Advanced Materials, 2011, 23, p. It is synthesized by a generally known method described in .1222-1225. The method for purifying the thienothiophene derivative represented by the general formula (1) is not particularly limited, and generally known methods such as recrystallization, column chromatography, and vacuum sublimation purification can be used. method. In addition, these methods can be used in combination as necessary.

A second object of the present invention is to provide an organic semiconductor device using the above-mentioned organic semiconductor thin film, and a third object is to provide a manufacturing method using such an organic semiconductor device.

The method for manufacturing an organic semiconductor device of the present invention is a method for manufacturing an organic semiconductor device including an organic semiconductor thin film, and is a method for forming an organic semiconductor thin film by the method for manufacturing an organic semiconductor thin film according to the present invention. The organic semiconductor device of the present invention is manufactured by the manufacturing method of the present invention described above. The organic semiconductor device manufactured by the manufacturing method of the present invention is not particularly limited as long as it has a structure in which a semiconductor layer containing an organic semiconductor thin film is sandwiched by electrodes, but an organic thin film transistor is preferred. The organic semiconductor device manufactured by the manufacturing method of the present invention is particularly preferably such that the two electrodes of the source electrode and the drain electrode are in contact with a semiconductor layer containing an organic semiconductor thin film, and are applied to a gate electrode through a gate insulating layer. The voltage of the other electrode of the electrode is an organic thin film transistor configured to control the current flowing between the source electrode and the drain electrode. That is, the organic semiconductor device manufactured by the manufacturing method of the present invention is particularly preferably an organic thin film transistor having the following organic field effect transistor, the organic field effect transistor having: source electrodes arranged in a spaced manner from each other. And a drain electrode, a semiconductor layer including an organic semiconductor thin film composed of an organic semiconductor material disposed between the source electrode and the drain electrode, and a gate electrode disposed so as to oppose the semiconductor layer And an insulating layer (gate insulating layer) disposed between the semiconductor layer and the gate electrode. The organic field-effect transistor is more preferably provided with the above-mentioned source electrode on a substrate. Electrode, drain electrode, semiconductor layer, gate electrode, and insulating layer.

Examples of the organic thin film transistor of the present invention are shown in Figs. 7 (a) and 7 (b).

The organic thin film transistor 10A shown in FIG. 7 (a) is called a bottom-gate organic field-effect transistor. The organic thin film transistor 10A is provided with a substrate 1, a gate electrode laminated on the substrate 1, and a gate insulation laminated on the gate electrode 2 (the inner surface of the surface facing the substrate 1). Layer 3, the source electrode 5 and the drain electrode 6 arranged on a part of the upper surface of the gate insulating layer 3 at a distance from each other, and including The semiconductor layer 4 of an organic semiconductor thin film composed of an organic semiconductor material on the source electrode 5 and the part of the drain electrode 6).

The organic thin film transistor 10B shown in FIG. 7 (b) is an organic field effect transistor, and includes: a substrate 1 ', a gate insulating layer 3' laminated on the substrate 1 ', and spaced from each other. The source electrode 5 and the drain electrode 6 disposed on a part of the gate insulating layer 3 '(the inner surface of the surface opposite to the substrate 1') include a gate insulating layer 3 'disposed on the gate insulating layer 3'. A semiconductor layer 4 of an organic semiconductor thin film made of an organic semiconductor material on the top (but excluding the portion provided with the source electrode 5 and the drain electrode 6), and a gate insulating layer provided on the top of the semiconductor layer 4 3. The gate electrode 2 laminated on the upper surface of the gate insulating layer 3, and the substrate 1 laminated on the upper surface of the gate electrode 2. In the organic thin film transistor 10B, one of the substrate 1 ′ and the gate insulating layer 3 ′ may be omitted. In addition, the organic thin film transistor of the present invention can be an organic thin film having a structure in which both the substrate 1 'and the gate insulating layer 3' are removed from the organic thin film transistor 10B (referred to as a top-gate organic field effect transistor). Transistor.

Next, an example of the organic thin film transistor of the present invention shown in Figs. 7 (a) and 7 (b) will be described.

For the substrates 1 and 1 ', a resin film can be used in addition to an inorganic substrate such as glass. The substrates 1 and 1 'are preferably a resin film in consideration of the flexibility of the organic thin film transistors 10A and 10B. Examples of the resin constituting the resin film include polyethylene terephthalate, polyethylene naphthalate, polyether fluorene, polyamine, polyimide, polycarbonate, and cellulose triacetate. Esters, polyethers, imines, etc. The types of the substrates 1 and 1 'can be selected according to the process temperature at the time of applying pressure and applying ultrasonic vibration according to need. In addition, in order to improve the surface smoothness of the substrates 1 and 1 ', a planarization layer may be provided on the substrates 1 and 1'. Among the resins constituting the resin film, inorganic oxide particles (for example, silicon dioxide particles) having an average particle size in the order of nanometers (for example, 5 nm) can be dispersed in order to improve metal adhesion or durability. These substrates 1 and 1 'are preferably those having a glass transition point of 100 ° C or higher, and more preferably those having a glass transition point of 150 ° C or higher. The thickness of the substrates 1 and 1 'is usually 1 μm to 10 mm, and preferably 5 μm to 3 mm.

When a resin film is used as the substrate 1, considering the bending resistance of the organic thin film transistor, the semiconductor film 4 can be formed by sandwiching the semiconductor layer 4 with the substrate 1 and 1 'like the organic thin film transistor 10B. In this configuration, it is preferable that the materials of the two base materials 1 and 1 'be the same. By using the substrates 1 and 1 'composed of the resin film, the organic thin-film transistor can be made flexible, and a flexible and lightweight organic thin-film transistor having high bending resistance can be realized, thereby improving organic Practicality of thin film transistors.

The source electrode 5, the drain electrode 6, and the gate electrode 2 are made of a conductive material (a material having conductivity). Examples of the conductive material include platinum, gold, silver, aluminum, chromium, tungsten, tantalum, nickel, cobalt, copper, iron, lead, tin, titanium, indium, palladium, aluminum, magnesium, calcium, barium, and lithium. , Potassium, sodium and other metals and alloys containing these; conductive inorganic oxides such as InO ₂ , ZnO ₂ , SnO ₂ , ITO (indium tin oxide); polyaniline, polypyrrole, polythiophene (PEDOT-PSS, etc.) ), Conductive polymers such as polyacetylene, poly-p-styrene, polydiacetylene; carbon materials such as carbon nanotubes and graphite. In order to reduce the contact resistance of the source electrode 5, the drain electrode 6, and the gate electrode 2, the various materials listed above can be doped with molybdenum oxide, or the above metals can be treated with thiol or the like. In addition, the above-mentioned conductive materials can also be used in conductive composite materials in which carbon black is dispersed among the materials listed above, or particles of metals such as gold, platinum, silver, copper, etc. are dispersed in the above listed materials. Conductive composite materials of various materials (but different from particles). When the organic thin film transistors 10A and 10B are operated, wiring is connected to the gate electrode 2, the source electrode 5, and the drain electrode 6. The wiring is also made of the same material as that of the gate electrode 2, the source electrode 5, and the drain electrode 6. The thicknesses of the source electrode 5, the drain electrode 6, and the gate electrode 2 vary depending on their materials, and are usually 1 nm to 10 μm, preferably 10 nm to 5 μm, and particularly preferably 30 nm to 1 μm.

The gate insulating layers 3 and 3 'are layers of an insulating material (an insulating material). The above-mentioned insulating material is, for example, a material which can be used for dispersing the following dielectric particles in a polymer, that is, a polypropionate (propionic acid resin) such as parylene, polymethyl methacrylate, or polystyrene. , Polyvinyl phenol, polyamide, polyimide, polycarbonate, polyester, polyvinyl alcohol, polyvinyl acetate, polyurethane, polyfluorene, fluorine resin, epoxy resin, phenol resin, etc. Polymers and copolymers combining these; inorganic oxides such as silicon dioxide, aluminum oxide, titanium oxide, tantalum oxide; strong dielectric inorganic oxides such as SrTiO ₃ , BaTiO ₃ ; silicon nitride, nitride Inorganic nitrides such as aluminum; inorganic sulfides; inorganic fluorides. The insulating material used for the gate insulating layer 3 is preferably confirmed in advance whether the damage is caused by pressure and ultrasonic vibration. It is the same as the base material 1. In addition to the thermal stability, pressure must be considered. And insulation damage caused by ultrasonic vibration. The thickness of the gate insulating layers 3 and 3 'varies depending on the insulating material used therein, and is usually 10 nm to 10 μm, preferably 50 nm to 5 μm, and particularly preferably 100 nm to 1 μm. When the organic thin-film transistor 10B having a structure in which the semiconductor layer 4 shown in FIG. 7 (b) is sandwiched between two substrates 1 and 1 'is used, the gate insulating layers 3 and 3' take the organic thin-film transistor 10B into consideration. The bending resistance is preferably made of the same material.

The semiconductor layer 4 includes an organic semiconductor thin film made of the aforementioned organic semiconductor material. As the semiconductor material constituting the semiconductor layer 4, the above-mentioned organic semiconductor material may be used alone, or the above-mentioned organic semiconductor material and at least one other semiconductor material may be used in combination. In order to improve the characteristics of the organic thin film transistors 10A and 10B, various additives may be mixed into the semiconductor material constituting the semiconductor layer 4 as needed. The thickness of the semiconductor layer 4 is preferably as thin as possible without losing necessary functions. Among the organic thin-film transistors 10A and 10B, if the semiconductor layer 4 has a predetermined thickness or more, the characteristics of the organic thin-film transistors 10A and 10B do not depend on the thickness of the semiconductor layer 4, but if the thickness of the semiconductor layer 4 becomes thick, it is more Cause leakage current Increase. On the contrary, when the thickness of the semiconductor layer 4 is too thin, since a path (channel) of electric charges cannot be formed in the semiconductor layer 4, the semiconductor layer 4 must have a suitable thickness. The thickness of the semiconductor layer 4 for the organic thin film transistors 10A and 10B to exhibit necessary functions is usually 1 nm to 5 μm, preferably 10 nm to 1 μm, and particularly preferably 10 nm to 500 nm.

In the organic thin film transistor of the present invention, another layer may be provided between the respective constituent elements or on the exposed surface of the respective constituent elements as required. For example, a thin film transistor protective layer for protecting the organic thin film transistor 10A may be formed on the semiconductor layer 4 of the organic thin film transistor 10A directly or through another layer. Thereby, the influence of external air such as humidity on the electrical characteristics of the organic transistor can be reduced, and the electrical characteristics of the organic transistor can be stabilized. In addition, electrical characteristics such as on / off of the organic transistor can be improved.

The material constituting the thin-film transistor protective layer is not particularly limited, and preferred examples thereof include a propionic acid resin such as epoxy resin, polymethyl methacrylate, polyurethane, polyimide, polyvinyl alcohol, Various resins such as fluororesins and polyolefins; inorganic oxides such as silicon oxide, aluminum oxide, and silicon nitride; and dielectrics such as nitrides. Particularly preferred are oxygen transmission rate, water transmission rate, and water absorption. Low rate resin (polymer). As the material constituting the thin-film transistor protective layer, a gas barrier protective material developed for an organic electroluminescent display can also be used. The thickness of the thin film transistor protective layer may be any thickness according to the purpose, and is usually 100 nm to 1 mm.

Next, a method for manufacturing an organic semiconductor device according to the present invention will be described in detail.

In the method for manufacturing an organic semiconductor device of the present invention, for example, an organic semiconductor material is disposed on a substrate on which an insulating layer and an electrode are formed, and an ultrasonic vibration is applied to the organic semiconductor material while applying pressure to the organic semiconductor device to manufacture the organic semiconductor device.

In the method for manufacturing an organic semiconductor device of the present invention, when the organic thin-film transistor is the following organic field-effect transistor, it preferably includes: before forming the organic semiconductor thin film by the method for manufacturing the organic semiconductor device of the present invention, An arrangement step of disposing an organic semiconductor material on the aforementioned substrate; the organic field effect transistor system is provided on the substrate with a source electrode and a drain electrode arranged in a spaced manner from each other, A semiconductor layer of an organic semiconductor thin film composed of an organic semiconductor material between the source electrode and the aforementioned drain electrode, a gate electrode disposed so as to oppose the aforementioned semiconductor layer, and an electrode disposed between the aforementioned semiconductor layer and the above An insulating layer between the gate electrodes. In this manufacturing method, the organic thin film transistor 10A shown in FIG. 7 (a) or the organic thin film transistor 10B shown in FIG. 7 (b) can be manufactured.

In the foregoing configuration step, for the aforementioned substrate on which the aforementioned source electrode and drain electrode are disposed, the organic semiconductor material may be arranged on the aforementioned substrate in a solid state or a molten state with the source electrode and The area between the drain electrodes or the vicinity thereof, or for the substrate on which the source electrode and the drain electrode are disposed above, a solution containing an organic semiconductor material is applied on the substrate, and then By drying, the organic semiconductor material is arranged in or near a region between the source electrode and the drain electrode on the substrate.

Here, the manufacturing method of the organic semiconductor device of the present invention will be described in detail based on the organic thin film transistor 10B of the example of FIG. 7 (b) using two kinds of substrates. The first substrate (referred to as "gate substrate 9") is a structure in which a gate electrode 2 and a gate insulating layer 3 are laminated on a substrate 1. The other substrate (referred to as "source-drain substrate 8") is a gate insulating layer 3 ', a source electrode 5, and a drain electrode 6 laminated on a substrate 1'. In the following description, the case where the semiconductor layer 4 is composed of only an organic semiconductor thin film will be described.

(Fabrication of Gate Substrate 9)

[Treatment of substrates 1 and 1 ']

The gate substrate 9 is produced by providing the gate electrode 2 and the gate insulating layer 3 on the substrate 1 described above. A surface treatment (cleaning treatment) may be performed on the surface of the substrate 1 in order to improve the wettability of each layer laminated on the substrate 1 (easiness of lamination). Examples of the surface treatment include acid treatment with hydrochloric acid, sulfuric acid, acetic acid, etc .; alkali treatment with sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia, etc .; ozone treatment; fluorination treatment; oxygen or argon, etc. Plasma treatment of plasma; formation of Langmuir-Blodgett film; electrical treatment of corona discharge and so on.

[Formation of the gate electrode 2]

A gate electrode 2 is formed on the substrate 1 using the above-mentioned conductive material (electrode material). Examples of the method for forming the gate electrode 2 include a vacuum evaporation method, a sputtering method, a coating method, a thermal transfer method, a printing method, and a sol-gel method. Wait. During or after the formation of the conductive material, the conductive material can be patterned as required so that the conductive material has a desired shape. Various methods can be used for the patterning method, and examples thereof include a photolithography technique that combines patterning and etching of a photoresist. In addition, the patterning method can also be applied to inkjet printing, screen printing, lithographic printing, letterpress printing, and other soft lithography techniques, as well as a combination of these techniques. The electrode formed by the printing method is sintered by applying energy such as heat and light until a desired conductivity is reached.

[Formation of Gate Insulation Layer 3]

Next, a gate insulating layer 3 is formed on the gate electrode 2 formed on the base material 1 using the insulating material (see FIG. 7 (b)). Examples of the method for forming the gate insulating layer 3 include coating methods such as a spin coating method, a spray coating method, a dip coating method, a casting method, a rod coating method, and a doctor blade coating method; a screen printing method, a lithographic printing method, and an inkjet method. And other printing methods; vacuum evaporation method, molecular beam epitaxial growth method, ion cluster beam method, ion plating method, sputtering method, atmospheric piezoelectric slurry method, CVD (chemical vapor growth) method and other dry process methods. The gate insulating layer 3 may be surface-treated. This can be considered to be able to easily control the molecular alignment or crystallinity of the interface portion between the semiconductor layer 4 and the gate insulating layer 3 that are formed after the surface treatment of the gate insulating layer 3, and reduce the substrate 1 or the gate. The trap site on the electrode insulating layer 3 can improve the carrier mobility and other characteristics of the organic thin film transistor 10B. The capture site refers to a functional group such as a hydroxyl group existing in the untreated substrate 1 or the gate insulating layer 3, and if such a functional group exists in the substrate 1 Or, in the gate insulating layer 3, electrons are attracted by the functional group, and as a result, the carrier mobility of the organic thin film transistor 10B is reduced. Therefore, reducing the collection site in the substrate 1 or the gate insulating layer 3 is sometimes effective in improving the carrier mobility of the organic thin film transistor 10B and other characteristics.

(Fabrication of source-drain substrate 8)

[Treatment of Substrate 1 ']

The gate substrate 9 is produced by providing a gate insulating layer 3 ', a source electrode 5, and a drain electrode 6 on the substrate 1' described above. The surface of the substrate 1 ′ is the same as the surface of the substrate 1, and the surface treatment described above can be performed.

[Formation of Gate Insulation Layer 3 ']

Next, the gate insulating layer 3 'is formed on the base material 1' using the above-mentioned insulating material (refer to FIG. 7 (b)). As the method for forming the gate insulating layer 3 ′, the same method as the method for forming the gate insulating layer 3 can be used. The gate insulating layer 3 'can be surface-treated in the same manner as the gate insulating layer 3.

[Formation of the source electrode 5 and the drain electrode 6]

Next, the source electrode 5 and the drain electrode 6 are formed on the gate insulating layer 3 'using the conductive material. The materials of the source electrode 5 and the drain electrode 6 may be the same or different. The method of forming the source electrode 5 and the drain electrode 6 can be the same as the method of forming the gate electrode 2. The conductive material constituting the source electrode 5 and the drain electrode 6 may be doped with molybdenum oxide in order to reduce the contact resistance of the source electrode 5 and the drain electrode 6. When the source is powered When the electrode 5 and the drain electrode 6 are made of a metal, the metal may be treated with thiol or the like. The molybdenum oxide, thiol, or the like can be laminated on the source electrode 5 and / or the drain electrode 6 by the same method as the method of forming a conductive material.

[Arrangement of organic semiconductor material on source-drain substrate 8]

Next, the organic semiconductor material is arranged on the source-drain substrate 8 manufactured by the method described above. The organic semiconductor material can be directly arranged in a solid state or a molten state such as a bulk powder or the like between the source electrode 5 and the drain electrode 6 on the source-drain substrate 8 without a solvent. The organic semiconductor material is arranged on the source electrode on the source-drain substrate 8 by a process (solution process) of coating or printing the solution containing the organic semiconductor material on the source-drain substrate 8 and drying it. The region between the electrode 5 and the drain electrode 6 or its vicinity. The solution process can be a printing method such as an inkjet method, a screen printing method, a lithographic method, a micro-contact printing method, or a coating method such as a drip casting method. In other solution processes, although the organic semiconductor material can be disposed on the source-drain substrate 8, in order to improve the utilization efficiency of the organic semiconductor material, a method in which a necessary amount of the organic semiconductor material can be disposed where necessary is preferred. The following is a detailed description of the arrangement method of organic semiconductor materials.

First, when a solid or molten organic semiconductor material is directly disposed on the source-drain substrate 8, the organic semiconductor material in the form of a bulk solid powder or a finely powdered organic semiconductor material is directly disposed or dispersed. In or near the region between the source electrode 5 and the drain electrode 6 on the source-drain substrate 8, or The organic semiconductor material in a molten state at a temperature is applied to a region between the source electrode 5 and the drain electrode 6 on the source-drain substrate 8 by various means such as an imprinter or a dispenser, or a method thereof, or the like. nearby. In simple terms, the organic semiconductor material is collected at the front end of a fully heated metal rod to become a molten state, and then the molten organic semiconductor material at the front end of the metal rod is directly applied to the source electrode on the source-drain substrate 8 The region between the electrode 5 and the drain electrode 6 or its vicinity.

Next, a method for disposing an organic semiconductor material on the source-drain substrate 8 by a solution process will be described. The so-called solution process means that a solvent-soluble organic semiconductor material such as a compound represented by the aforementioned general formula (1) is dissolved in an organic solvent in advance, and the obtained solution of the organic semiconductor material is dried after being coated or printed. To arrange organic semiconductor materials where desired. The method of disposing organic semiconductor materials by coating or printing and drying of the solution, that is, the solution process, does not need to configure the environment when the organic thin film transistor 10B is manufactured into a vacuum or high temperature state, and can produce large areas of organics at low cost. The thin film transistor 10B is also industrially advantageous. In addition, in the method for manufacturing an organic semiconductor device of the present invention, when the organic semiconductor material is arranged on the source-drain substrate 8 by using a solution process, it may be considered that the organic semiconductor material is cooled after the end of the ultrasonic vibration application. During the process, the orientation of the crystals of the organic semiconductor material is re-aligned to make the orientation of the crystals uniform. Therefore, in the stage where the organic semiconductor material is crystallized from the solution, the crystal orientation can be arbitrary. After the solution is coated or printed, it can be only The organic solvent contained in the solution was evaporated. Therefore, after the application or printing of the solution, in order to achieve a uniform crystal orientation For crystallization, it is necessary to implement a process of controlling the crystal orientation by long-term baking or re-alignment of crystals by subsequent processing.

The organic semiconductor material may be disposed on a region (channel) between the source electrode 5 and the drain electrode 6 on the source-drain substrate 8 or near the region (channel) outside the region (channel). When the organic semiconductor layer is formed only by a method such as a drop casting method or an inkjet method, which coats or prints the solution, in order to cover the source electrode 5 and the drain electrode 6 on the source-drain substrate 8 with the organic semiconductor layer The area (channel) between them must take into account the positional accuracy of the ink-jet ejection accuracy of the organic semiconductor material. In contrast, according to this method, in the step of disposing the organic semiconductor material, it is not necessary to completely cover the area (channel) between the source electrode 5 and the drain electrode 6 on the source-drain substrate 8 with the organic semiconductor layer. ), It is not necessary to require high position accuracy for the equipment used for coating or printing. The position where the organic semiconductor material is arranged also varies depending on the amount of the organic semiconductor material. In order to obtain a good organic semiconductor thin film, it is preferable to arrange the organic semiconductor material near the channel outside the channel. Generally, it is preferable to arrange the organic semiconductor material. The distance from the source electrode 5 outside the channel is within 5 mm.

[Formation of semiconductor layer 4 and production of organic thin film transistor 10B]

Next, the gate substrate 9 is superposed on the source-drain substrate 8 on which an organic semiconductor material is disposed. It is used to obtain the organic semiconductor material sandwiched between the source-drain substrate 8 and the gate substrate 9 obtained in this way, and apply ultrasonic vibration to the organic semiconductor material through the gate substrate 9 while applying pressure to the organic semiconductor material. Energy is imparted to the organic semiconductor material. Take this The organic semiconductor material is thinned to form a semiconductor layer 4 composed of an organic semiconductor thin film as a channel, and the source-drain substrate 8 and the gate substrate 9 are pressed together to complete an organic thin film transistor 10B. The conditions provided by the pressure and the ultrasonic vibration can be used to produce the organic thin film transistor 10B using the same conditions as the method for forming the organic semiconductor thin film described above. According to the nature of the organic semiconductor material, the conditions imposed by the pressure and ultrasonic vibration of the oscillation time (welding time), amplitude, and pressure are optimized. If necessary, the base 1 (organic semiconductor material) on which the base 1 is placed (heating base 26) is heated by conductive heating means (heater 26a, etc.), whereby the base 1 (organic semiconductor material) is conductively heated (base heating). When the method for forming an organic semiconductor thin film of the present invention is used, it is not necessary to perform a long baking step as in the past, and if the conditions imposed by pressure and ultrasonic vibration are optimized, it can be as short as 1 second or less. Time to form an organic semiconductor thin film.

Next, a method of forming the semiconductor layer 4 using the ultrasonic welding machine 20 shown in FIG. 1 as an embodiment of a method of forming the semiconductor layer 4 made of an organic semiconductor thin film will be described with reference to FIGS. 2 to 6.

First, as shown in FIG. 2, an organic semiconductor material 7 is sandwiched between a source-drain substrate 8 and a gate substrate 9, and the organic semiconductor material 7 is placed on a heating base 26 of the ultrasonic fusion machine 20. Next, as shown in FIG. 3, the welding head 24 is lowered and pressure is applied to the object to be processed (that is, the organic semiconductor material 7). Next, as shown in FIG. 4, in a state where pressure is applied to the object to be processed (that is, the organic semiconductor material 7), ultrasonic vibration is applied to the organic semiconductor material 7 from the welding head 24 through the gate substrate 9, thereby, Heated organic half Conductive material 7 (applies energy to organic semiconductor material 7). Thereby, the thickness of the organic semiconductor material 7 becomes thin. Next, as shown in FIG. 5, in a state where pressure is applied to the object to be processed (that is, the organic semiconductor material 7), the ultrasonic vibration is applied to the organic semiconductor material 7 to cool the organic semiconductor material 7. As a result, a thin film (organic semiconductor thin film) of an organic semiconductor material having a thinner thickness than the original organic semiconductor material 7 is formed as the semiconductor layer 4. Finally, as shown in FIG. 6, the welding head 24 is raised and the application of the pressure is terminated, thereby completing the organic thin film transistor 10B.

Generally speaking, the operating characteristics of organic thin-film transistors depend on the carrier mobility and conductivity of the semiconductor layer, the capacitance of the insulating layer, and the component composition (the distance between the source electrode and the drain electrode, the source electrode and the drain electrode). Electrode width, thickness of the insulating layer, etc.). In order to obtain a semiconductor layer 4 composed of an organic semiconductor material with a high carrier mobility, the organic semiconductor material is required to have an alignment order in a certain direction (the orientation of the crystals is uniform, and more crystals are aligned in a certain direction). In the method for manufacturing an organic semiconductor device of the present invention, during the cooling of the organic semiconductor material after the end of the ultrasonic vibration application, the crystals of the organic semiconductor material are re-aligned, and an organic semiconductor material having an alignment order in a certain direction can be obtained. Constituted semiconductor layer 4. In addition, in an organic thin film transistor 10B having two substrates 1 and 1 'and two gate insulating layers 3 and 3', if the same materials are used for the substrates 1 and 1 'and the gate insulating layers 3 and 3 are used 'Using the same material, the structure of the organic thin film transistor 10B can be formed into a symmetrical sandwich structure with the semiconductor layer 4 as the center. As a result, it is difficult to be affected by deformation and the like caused by different materials, and has high Bending resistance organic thin film transistor 10B.

Furthermore, since the method for manufacturing an organic semiconductor device of the present invention can form an organic semiconductor thin film in a short time, it is the same as the conventional manufacturing method for forming an organic semiconductor thin film by a vacuum evaporation process, or by another coating method or Compared with the conventional manufacturing method of forming an organic semiconductor thin film by a printing method (solution process), this processing amount is high, and it can also be applied to the manufacture of an organic semiconductor device with a very low cost and a large area display application. In addition, since the method for manufacturing an organic semiconductor device of the present invention can form an organic semiconductor thin film in a short time, it can also realize a method for manufacturing a sheet-to-sheet method or a roll-to-roll method.

The organic semiconductor device of the present invention can be applied as a switching element of an active matrix of a display. Examples of the display include a liquid crystal display, a polymer-dispersed liquid crystal display, an electrophoretic display, an electroluminescence (EL) display, an electrochromic display, and a particle rotation display. In addition, the organic semiconductor device of the present invention can also be applied as a digital element or an analog element such as a memory circuit element, a signal driver circuit element, a signal processing circuit element, or the like. By combining these elements, an IC ( Integrated circuit) card or IC tag. Furthermore, the organic semiconductor device of the present invention can be changed in its characteristics by an external stimulus such as a chemical substance, so it can also be expected to be applied as a FET (field-effect transistor) sensor.

[Example]

Hereinafter, the present invention will be described in more detail with examples, but these examples are only for easy understanding of the present invention, and the present invention is not limited thereto. In these embodiments.

[Example 1]

A compound represented by the following formula (2) (hereinafter referred to as "compound (2)" (2,7-dioctyl [1] benzothieno [3,2-b] [1] benzothiophene) Solid (melting point: 127 ° C), The organic semiconductor material is placed on the front end of a heated metal rod to be in a molten state, and the semiconductor material in the molten state at the front end of the metal rod is placed on a polyimide film (product name "Pomiran (registered trademark)""N", manufactured by Arakawa Chemical Industry Co., Ltd., has a structure in which a silica having an average particle diameter of 5 nm and a nanometer silica particle dispersed in a polyimide matrix is mixed with a polyimide film). The thickness of the semiconductor material at this time is several μm. Then, another compound of the same polyimide film was superimposed on the polyimide film through the compound (2).

The compound (2) sandwiched between the two polyimide films obtained in this way is used instead of sandwiching between the source-drain substrate 8 and the gate substrate 9 as shown in FIG. 2. An organic semiconductor thin film is formed in the same manner as the manufacturing method shown in FIGS. 2 to 6 except that the organic semiconductor material 7 is held as a target.

That is, first, in the same manner as in FIG. 2, the object to be treated (the compound (2) is sandwiched between two polyimide films) is set on the ultrasonic wave of FIG. 1 having the heating base 26. An example of a fusion splicer 20, a commercially available ultrasonic fusion splicer (consisting of a stamped body with the product name "Σ P-30B" and an oscillator with the product name "Σ G-620B", Varitronix Electronics Co., Ltd. System, the maximum amplitude (100% amplitude) is 25 μm, the number of vibrations (frequency) is 28.5 kHz, the shape of the welding head: quadrangular prism (shaved edge), the size of the welding head surface (processing area): 64 mm ² ) on a heating base 26.

Next, the heating pedestal 26 is heated by the heater 26a so that the temperature (surface temperature) of the heating pedestal 26 becomes 100 ° C (heating for conducting conductive heating of the compound (2)), as in FIG. 3, The welding head 24 is lowered and a pressure of 0.15 MPa is applied to the object to be processed (that is, the compound (2)). Then, in the same manner as in FIG. 4, in a state where a pressure of 0.15 MPa is applied to the object to be processed (that is, the compound (2)), the amplitude of the ultrasonic vibration is 25%, 30%, or 35%, and the ultrasonic vibration is On condition that the oscillation time is 1 second or less, the ultrasonic welding machine performs ultrasonic oscillation, thereby applying ultrasonic vibration to the compound (2) and heating the compound (2).

Next, in the same manner as in FIG. 5, in a state where a pressure is applied to the object to be processed (that is, the organic semiconductor material), the ultrasonic oscillation of the ultrasonic fusion machine is ended to cool the organic semiconductor material, thereby forming a compound having a thickness greater than the original compound. (2) A thinner film (organic semiconductor film) of the compound (2) is used as the semiconductor layer 4. Finally, in the same manner as in FIG. 6, the welding head 24 is raised and the application of the pressure is ended to obtain an organic semiconductor thin film.

The temperature change of the organic semiconductor material (compound (2)) at this time is shown in FIG. 8. From this result, it was confirmed that ultrasonic waves The amplitude of the vibration changes to control the temperature of the organic semiconductor material. At the same time, as the ultrasonic vibration ends, the temperature of the organic semiconductor material decreases rapidly.

From these contents, it was confirmed that by applying ultrasonic vibration while applying pressure to the organic semiconductor material, the thinning of the organic semiconductor material can be formed, that is, the organic semiconductor thin film. The first table shows the maximum reaching temperature of the organic semiconductor material under each amplitude condition and the presence or absence of thinning of the organic semiconductor material. From the results in Table 1, it can be seen that the organic semiconductor material can be made into a thin film under any conditions to form an organic semiconductor thin film of several tens of nm.

The temperature of the organic semiconductor material is measured by the following method. That is, a sheet-shaped temperature sensor is provided on the polyimide film to replace the organic semiconductor material (compound (2)), except that the other processes are performed in the same manner as in the formation of the above-mentioned organic semiconductor thin film, and The change in the temperature of the sheet-shaped temperature sensor (the temperature of a portion between the two polyimide films) was measured by the sheet-shaped temperature sensor.

[Example 2]

In this embodiment, it is an example of manufacturing the organic thin film transistor 10B shown in FIG. 7 (b). First, a thickness of 900 nm was used to form "Parylene (registered trademark) C" (manufactured by Parylene Japan Co., Ltd.) as the gate insulating layer 3 'on a 12 μm-thick polyimide film (product name) "Pomiran (registered trademark) N"), on top of its Parylene film, a gold electrode with a channel length of 20 μm and a channel width of 5 mm was formed as the source electrode 5 and the drain electrode 6 to obtain a source. Pole-drain substrate 8. On the other hand, a gold electrode serving as the gate electrode 2 was formed on a polyimide film (product name "Pomiran (registered trademark) N") having a thickness of 12 μm as the base material 1. On the upper part of the gold electrode, A thickness of 900 nm formed a film of parylene as the gate insulating layer 3 to obtain a gate substrate 9.

Next, as shown in FIG. 9, on the source-drain substrate 8, from the source electrode 5 and the drain electrode 6 (and the region therebetween) toward the end side of the source-drain substrate 8 ( On the right end side in Fig. 9), a solid (melting point: 127 ° C) as the compound (2) of the organic semiconductor material is disposed at a distance of about 200 µm. Next, the gate substrate 9 is superposed on the solid source-drain substrate 8 on which the compound (2) is disposed.

Then, the compound (2) sandwiched between the source-drain substrate 8 and the gate substrate 9 obtained in this manner was used instead of sandwiching between two polyimide films in Example 1 In the case of the compound (2), the temperature of the heating pedestal was changed to 95 ° C, and the amplitude of the ultrasonic vibration was changed to 45%. The formation method is the same, and an organic semiconductor thin film composed of the compound (2) is formed. At this time, the highest reach of organic semiconductor materials The temperature was 230 ° C.

Figures 9 to 11 show the results of observing changes in the organic semiconductor material of Example 2 with a polarizing microscope. FIG. 9 shows the appearance of the organic semiconductor material at a point in time when the organic semiconductor material (compound (2)) is sandwiched between the source-drain substrate 8 and the gate substrate 9 on the heating base 26. FIG. 10 shows the appearance of the organic semiconductor material after the organic semiconductor material is heated by the heating base 26 at 100 ° C. FIG. 11 shows that after the application of the ultrasonic vibration and the application of the pressure, the sample taken out from the ultrasonic welding machine (formed between the source-drain substrate 8 and the gate substrate 9) was confirmed with a polarizing microscope. Result of organic semiconductor material of organic semiconductor thin film). As shown in FIG. 11, the semiconductor layer 4 made of an organic semiconductor thin film is formed between the source electrode 5 and the drain electrode 6 (the two vertical lines in the center), and it can be seen that an organic thin film transistor 10B can be produced.

Next, the semiconductor characteristics of the organic thin film transistor 10B obtained in Example 2 were measured. The application of the gate voltage and the measurement of the gate current of the organic thin film transistor 10B are performed using a KEITHLEY 2635A SYSTEM Source Meter. The application of the source-drain voltage and the measurement of the drain current of the organic thin film transistor 10B are Use KEITHLEY 6430 SUBFEMTO AMP REMOTE Source Meter. The current-voltage characteristics of the organic thin-film transistor 10B were measured under the conditions that the drain voltage of the organic thin-film transistor 10B was set to -30 V and the gate voltage Vg of the organic thin-film transistor 10B was changed from 30 to -30 V. . From the current-voltage characteristics of the obtained organic thin film transistor 10B, the mobility and the threshold voltage of the organic thin film transistor 10B were calculated. The calculated mobility is 0.038 cm ² / V · s, and the calculated threshold voltage is 1.2 V. An organic thin film transistor 10B having the characteristics of a p-type semiconductor in the semiconductor layer 4 can be obtained.

In order to confirm the resistance of the 900 nm-thick parylene film used for the gate insulating layers 3 and 3 'to pressure and ultrasonic vibration, the conditions were the same as when the organic semiconductor film was formed in this example. , The parylene film is subjected to a process of applying pressure by an ultrasonic welding machine and applying ultrasonic vibration. As a result, no substantial change in the leakage current density was observed before and after the treatment, and it was confirmed that the insulation properties of the parylene film were not deteriorated by the pressure of the ultrasonic welding machine and the application of ultrasonic vibration.

[Example 3]

The source electrode 5 and the drain electrode 6 of Example 2 were treated with pentafluorothiophenol prior to the application of pressure and ultrasonic vibration. Except that, other methods were performed in the same manner as in Example 2 to obtain an organic compound. Thin film transistor 10B. The mobility and the threshold voltage of the organic thin film transistor 10B obtained in this example were measured in the same manner as the measurement method in Example 2. The mobility and threshold voltage of the organic thin film transistor 10B obtained in this example are calculated. The calculation results of the mobility and the threshold voltage are shown in Table 2. In addition, the semiconductor layer 4 of the organic thin film transistor 10B obtained in this embodiment exhibits characteristics of a p-type semiconductor.

[Example 4]

Changing the channel length of the source electrode 5 and the drain electrode 6 in Example 3 Except that it was 100 μm, the other parts were the same as in Example 3, and an organic thin film transistor 10B was obtained. The semiconductor characteristics of the organic thin film transistor 10B obtained in this example were measured in the same manner as the measurement method of Example 2, and the mobility and threshold voltage of the organic thin film transistor 10B obtained in this example were calculated. The calculation results of the mobility and the threshold voltage are shown in Table 2. In addition, the semiconductor layer 4 of the organic thin film transistor 10B obtained in this embodiment exhibits characteristics of a p-type semiconductor.

[Example 5]

Using an inkjet device (manufactured by Fuji Film Co., Ltd., model "DMP-2831"), an organic semiconductor material composed of a 2% by weight tetrahydronaphthalene solution of compound (2) was printed on a polyimide film having a thickness of 12 μm ( The product name is "Pomiran (registered trademark) N"), the solution is naturally dried, and the solvent (tetrahydronaphthalene) is removed, and then the organic semiconductor material is disposed on the polyimide film. As shown in FIG. 12, the shape of the organic semiconductor layer (layer of an organic semiconductor material) shortly after printing is extremely rough, and the maximum thickness of the organic semiconductor layer is 450 nm. Then, another organic polyimide film was superimposed on the polyimide film through the organic semiconductor material (compound (2)).

Next, the temperature (surface temperature) of the heating pedestal 26 was 100 ° C, the pressure of the object (organic semiconductor material) was 0.15 MPa, the amplitude of the ultrasonic vibration was 50%, and the oscillation time of the ultrasonic vibration was 1 second The conditions were the same as in Example 1, and the ultrasonic fusion splicer was subjected to ultrasonic oscillation. It was confirmed that the maximum reaching temperature of the organic semiconductor material (compound (2)) was 180 ° C. After the ultrasonic welding process, an organic semiconductor thin film as shown in FIG. 13 was formed.

[Example 6]

Between the source electrode 5 and the drain electrode 6 of the source-drain substrate 8 used in Example 2, using the inkjet device used in Example 5, 2% by weight of tetrahydrogen from compound (2) was printed. An organic semiconductor material composed of a naphthalene solution, which allows the solution to dry naturally and removes the solvent (tetrahydronaphthalene). By printing the organic semiconductor material, a linear pattern is drawn along the source electrode 5, but as the solution dries, the organic semiconductor layer (layer of the organic semiconductor material) is broken in the channel and becomes a discontinuous organic semiconductor. Layer (Figure 14). Then, the gate substrate 9 used in Example 2 is superposed on the source-drain substrate 8 through the organic semiconductor material (compound (2)), and the organic semiconductor material is sandwiched between the source-drain substrate 8 and Under the same conditions as in Example 5, the gate substrate 9 was subjected to ultrasonic oscillation by an ultrasonic fusion machine to obtain an organic semiconductor thin film. Thereby, an organic thin film transistor 10B is obtained. A polarizing microscope image of the obtained organic semiconductor thin film is shown in FIG. 15. From this image, it was confirmed that an organic semiconductor film having a uniform channel by ultrasonic fusion processing can be obtained.

[Comparative Example 1]

First, in the same manner as in Example 2, a compound (2) with a source-drain substrate 8 and a gate substrate 9 sandwiched therebetween was obtained as an object to be processed. Then, following the non-patent literature (Physica Status Solidi A, Volume 210, Issue 7, p. 1353-1357 (2013)), the hot stamping method (the above-mentioned non-patent Fig. 1 (b)) of the literature processes the object to be treated to thin the compound (2). The time taken for thinning was 2 minutes. After being formed into a thin film, the object to be treated is cooled at a cooling rate of 1.5 ° C./min, whereby an organic thin film transistor for comparison which is the same as that of Example 2 (except that the semiconductor characteristics are different from Example 2) can be obtained.

The semiconductor characteristics of the obtained comparative organic thin film transistor were measured in the same manner as in Example 2. As a result, the mobility of the comparative organic thin film transistor was 0.052 cm ² / Vs, and the threshold voltage was -15.8V. The semiconductor characteristics of the organic thin film transistor 10B of 2 are almost the same. However, in this comparative example, the time (process time) required for thin film formation is 2 minutes as described above, which is significantly worse than the time (1 second) required for thin film formation in Example 2, and the pressure required for thin film formation As described above, it is 1.6 MPa, which is also significantly deteriorated compared with the pressure (0.15 MPa) required for thinning in Example 2.

From the results described in the examples, it is shown that an organic semiconductor thin film can be formed not only by a method of applying an ultrasonic vibration while applying pressure to an organic semiconductor material to thin the organic semiconductor material, but also using this method The fabricated organic semiconductor device has high semiconductor characteristics. In addition, it was confirmed that when forming an organic semiconductor thin film, Without the need for tedious and precise process control for vacuum evaporation or crystal growth, organic semiconductor thin films can be formed in a very short time. Therefore, it was confirmed that the manufacturing method of the organic semiconductor device of each Example is a manufacturing method with a high throughput.

Claims (9)

An organic semiconductor thin film forming method is a method for forming an organic semiconductor thin film composed of an organic semiconductor material, and is characterized in that ultrasonic vibration is applied while applying pressure to an organic semiconductor material sandwiched between a pair of substrates. In order to make the organic semiconductor material into a thin film, the aforementioned one pair of base materials is a resin film. The method for forming an organic semiconductor thin film according to item 1 of the scope of patent application, wherein the solid state organic semiconductor material is phase-transformed by applying ultrasonic vibration while applying pressure to the organic semiconductor material, and then the organic semiconductor material is formed. By recrystallization, the organic semiconductor material is thinned. The method for forming an organic semiconductor thin film according to item 1 or 2 of the scope of application for a patent, wherein the organic semiconductor material is subjected to conduction heating while being subjected to ultrasonic vibration. An organic semiconductor device manufacturing method is a method for manufacturing an organic semiconductor device including an organic semiconductor thin film, characterized in that the organic semiconductor thin film is formed by a forming method as described in item 1 or 2 of the scope of patent application. The method for manufacturing an organic semiconductor device according to item 4 of the scope of patent application, wherein the organic semiconductor device is an organic thin film transistor. The method for manufacturing an organic semiconductor device according to item 5 of the scope of the patent application, wherein the organic thin film transistor is an organic field effect transistor, and the organic field effect transistor system is provided on the substrate with: A provided source electrode and a drain electrode, a semiconductor layer including an organic semiconductor thin film made of an organic semiconductor material, disposed between the source electrode and the drain electrode, and facing the semiconductor layer A gate electrode provided and an insulating layer disposed between the semiconductor layer and the gate electrode; the manufacturing method includes: before forming the organic semiconductor thin film, disposing an organic semiconductor material on the substrate; Configuration steps. The method for manufacturing an organic semiconductor device according to item 6 of the scope of the patent application, wherein, in the aforementioned disposing step, the aforementioned substrate on which the aforementioned source electrode and drain electrode are disposed is in a solid state or melted. In a state, an organic semiconductor material is arranged in or near a region between the source electrode and the drain electrode on the substrate. The method for manufacturing an organic semiconductor device according to item 6 of the scope of patent application, wherein, in the aforementioned disposing step, an organic semiconductor material will be contained in the substrate on which the source electrode and the drain electrode are disposed. After the solution is applied on the substrate, and then dried, the organic semiconductor material is arranged in or near the region between the source electrode and the drain electrode on the substrate. An organic semiconductor device is manufactured by a manufacturing method as described in item 6 of the scope of patent application.