JP4713818B2 - Organic transistor manufacturing method and organic EL display device manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing an organic transistor using inkjet printing and a method for manufacturing an organic EL display device.
[0002]
[Prior art]
In recent years, display devices such as flat panel displays using organic semiconductor devices such as organic light-emitting elements and organic transistors have been developed.
When a flat panel display is driven by an active matrix circuit, it is necessary to provide a drive circuit that performs light emission control for each pixel. Conventionally, a polysilicon TFT (thin film transistor) or the like has been used for this drive circuit. However, since the processing temperature in the manufacturing process exceeds 350 ° C., there is a problem that usable substrate materials are limited.
[0003]
On the other hand, since an organic transistor (organic TFT) has a low processing temperature in the manufacturing process, it can be formed on a substrate that is sensitive to high temperatures such as plastic. For this reason, development of a thin, lightweight and flexible display using an organic transistor in a drive circuit has been attempted.
[0004]
A structure of a general organic transistor is shown in FIG. In this example, a source electrode 93, a drain electrode 92, an organic semiconductor layer 94, a gate insulating layer 95, and a gate electrode 91 are stacked on the substrate 100 in order from the lower layer. As a material constituting each layer, a metal or a conductive organic material is used for the electrode, and an organic or inorganic material is used for the gate insulating layer 95.
[0005]
In such an organic transistor manufacturing process, the organic material has a property of deteriorating due to moisture or heat, and therefore, it is not preferable to perform steps such as photolithography and etching after the organic material is formed. For this reason, after the organic material film is formed, a pattern is formed by a vapor deposition method through a shadow mask.
[0006]
However, the above-described deposition needs to be performed in a vacuum, and the deposition source and the shadow mask must be changed every time the layer to be deposited changes.
As a countermeasure, it has been proposed that the constituent material of each layer is a liquid organic material dissolved in a solvent, and a pattern is formed by applying a printing process such as inkjet printing or screen printing (see, for example, Patent Document 1). . Such pattern formation using a printing process can be carried out at atmospheric pressure and is simple.
[0007]
In particular, since ink jet printing can directly draw a pattern, a mask is not necessary, and the manufacturing process can be greatly simplified. Further, since the material is applied only to the pattern forming position, the material is not wasted and the material cost can be reduced.
[0008]
[Patent Document 1]
Special table 2002-502098
[0009]
[Problems to be solved by the invention]
However, in the ink jet printing as described above, since it is difficult to reduce the discharge amount of the liquid material, a fine pattern cannot be formed with high accuracy. As a result, there was a problem that the gate electrode having a pattern of several microns square could not be formed with high accuracy, and the characteristics of the produced organic transistor varied.
[0010]
In addition, in inkjet printing, since the film thickness of the applied material varies depending on the variation in the discharge amount of the liquid material and the surface condition (irregularity and wettability) of the application position, it is difficult to control the film thickness and reduce the film thickness. However, since the characteristics of the element greatly change depending on the film thickness of the gate insulating layer in the TFT, there is a problem in forming the element by using the ink jet printing.
[0011]
Furthermore, the pattern applied by ink jet printing also has a problem that the upper surface and the end surface are curved surfaces. For example, when the source electrode and the drain electrode are formed by ink jet printing, the end surfaces of the opposing source electrode and the drain electrode are curved surfaces, so that the electrode spacing is different between the center and the end of the electrode even in the same element. End up. When the semiconductor layer is formed between the source and drain electrodes by ink jet printing, the channel thickness and the channel length of the formed transistor channel are different depending on the position in the same element. When a plurality of transistors having such channel thickness and channel length that are not constant are formed, it is very difficult to suppress variation in characteristics.
[0012]
The present invention has been proposed on the basis of the above-described conventional circumstances, and provides a manufacturing method capable of manufacturing a homogeneous organic transistor and an organic EL display device at low cost by a simple process using ink jet printing. Objective.
[0013]
[Means for Solving the Problems]
The present invention is premised on a manufacturing method in which an organic transistor is formed by dissolving a material of an organic transistor in a solvent to form a liquid material and applying the liquid material.
[0014]
The present invention employs the following means in order to achieve the above object. That is, according to the present invention, in the method for producing an organic transistor, when a charge is applied to a predetermined position on the surface to be coated, a charge having a polarity opposite to the charge is applied to the coating material, and the material is applied by inkjet printing. In addition, the material provided with the electric charge by Coulomb force is guided to the predetermined position. Such charge application is performed by irradiating a target position with a short pulse laser such as a picosecond laser or a femtosecond laser.
[0015]
In this way, even when the material applied by inkjet printing is applied at a position different from the design position (the predetermined position), the application material can be adhered to the design position in a self-aligned manner by the action of the Coulomb force. it can. It is also possible to prevent the liquid material from spreading along the substrate surface after application.
[0016]
Further, the present invention provides a method for manufacturing an organic transistor in which a pattern is formed by applying a liquid material, wherein a recess is formed at a predetermined position on the surface to be applied, and the coating material is applied by ink jet printing to the recess. Like to deposit Good . For example, the concave portion is formed by irradiation with a short pulse laser such as a picosecond laser or a femtosecond laser.
[0017]
In this case, the liquid material can be prevented from spreading along the substrate surface after application. Further, if a plurality of layers (for example, an organic semiconductor layer and a gate insulating layer) are deposited in the same recess, alignment is not necessary.
[0018]
According to the present invention, in a method for manufacturing an organic transistor in which a pattern is formed by applying a liquid material, a pattern is formed by ink jet printing, and then the pattern is formed by irradiating a laser. Good .
[0019]
As a result, it is possible to form a fine pattern, flatten the surface, and make the film thickness uniform, which has been difficult only by inkjet printing. In particular, it can be applied to forming a source electrode and a drain electrode having a predetermined electrode interval by separating one electrode pattern, forming an electrode pattern to a predetermined size, and forming a layer to be processed to a predetermined thickness. The variation in characteristics of the manufactured organic transistor can be reduced. The above molding may be applied to a material applied to the entire surface of the substrate by spin coating or the like.
[0020]
In addition, it is possible to perform fine pattern formation more efficiently by applying a combination of the above-described material application with charge application or the material application with recess formation and the above-described laser molding. Become. And when forming each layer of an organic transistor, an organic transistor with a small characteristic dispersion | variation can be produced by combining the above methods suitably.
[0021]
By the way, the above-described manufacturing method can also be applied to a manufacturing method of an active matrix organic EL display device including an organic transistor. That is, a driving circuit composed of a switching organic transistor and a driving organic transistor is formed in an array by appropriately combining the above manufacturing methods. If an organic EL lower layer electrode of each pixel is formed so as to be connected to each driving organic transistor, and an organic light emitting layer and an organic EL upper layer electrode are formed on the organic EL lower layer electrode, an active matrix organic EL display device Can be made. Note that a power supply line necessary for operating each pixel, and a data line and a scanning line connected to the address instruction circuit may be appropriately formed when the source / drain electrodes and the gate electrode of the organic transistor are formed.
[0022]
In this way, since the variation in driving current of each driving organic transistor can be reduced, an active matrix organic EL display device with small variation in emission intensity can be manufactured.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0024]
A schematic top view of an organic EL display device having an organic transistor (organic TFT) exemplified in each embodiment is shown in FIG. FIG. 1 shows one of the pixels arranged in an array on the substrate, and shows only the organic TFT portion. An organic EL element is formed on the organic TFT portion, and the organic EL element and the organic TFT portion are connected via an organic EL element connection port 3.
[0025]
In the example of FIG. 1, each pixel includes a driving circuit including a switching TFT 1 and a driving TFT 2. In each electrode of the switching TFT 1, the gate electrode 11 is connected to the scanning line 5, the drain electrode 12 is connected to the data line 4, and the source electrode 13 is connected to the gate electrode 21 of the driving TFT 2. In addition, each electrode of the driving TFT 2 has a drain electrode 22 connected to the power supply line 6 and a source electrode 23 connected to the organic EL lower layer electrode (the names of the source electrode and the drain electrode described above depending on the type of carrier of the TFT). Will be replaced, but in the following description will be made with this designation.)
[0026]
In the above structure, the switching TFT 1 is turned ON / OFF in accordance with signals on the data line 4 and the scanning line 5 to perform ON / OFF control (light emission control of the organic EL element) of the driving TFT 2. In the following embodiment, it is assumed that a positive potential is applied to the power supply line 6.
[0027]
In the following embodiments, in each layer, when the application of the liquid material is completed, a drying process is performed in which the solvent is evaporated and solidified.
[0028]
In the following embodiments, it is assumed that a short pulse laser such as a picosecond laser or a femtosecond laser is used as the laser.
[0029]
(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 2 is an explanatory view showing a manufacturing process of the organic TFT portion of the first embodiment, and FIG. 3 is an explanatory view showing a manufacturing process of the organic EL element portion of the first embodiment. 2 and 3 show a top view of each step and a cross-sectional view taken along AA ′ in FIG.
[0030]
As shown in FIG. 2A, first, electrodes 10, 20, data lines 4, and power supply lines 6 are formed on a resin-made flexible substrate made of PET (poly-ethylene terephthalate) or the like, or a substrate 100 made of glass or the like. Is applied by ink jet printing. For this electrode, for example, a metal such as aluminum or gold diffused in a solvent, or an organic conductor such as a polythiophene derivative (PEDOT: poly-ethylenedioxythiophene) can be used.
[0031]
Ink jet printing is not particularly limited as long as it can eject a liquid material and apply it to the surface to be printed.
[0032]
In the present embodiment, charges having different polarities are applied to the application target position on the substrate and the application material. In other words, a laser or the like is applied to the position (design position) where the material on the surface to be applied is applied to impart either positive or negative charge, and the liquid is applied by irradiation with a laser or between the electrodes for charging. One of the positive and negative charges is imparted to the material. In FIG. 4A, a positive charge 105 is applied to the substrate 100 by the laser 102, and the laser material 103 is irradiated to the liquid material 104 immediately after the inkjet nozzle 101 discharges (while not yet reaching the substrate). The case where a negative charge 106 is added is shown.
[0033]
In this way, even when the material applied by inkjet printing is applied at a position different from the design position, the application material can be attached to the design position by the action of Coulomb force (FIG. 4B). Further, it is possible to prevent the applied liquid material from spreading along the substrate surface.
[0034]
The transistor positions of the electrodes 10 and 20 formed as described above are irradiated with laser to separate the electrode 10 to obtain the source electrodes 13 and 23 and the drain electrodes 12 and 22 (FIG. 2B).
[0035]
FIG. 5 shows the formation of the source / drain electrodes in this step. By the laser irradiation, the electrode 10 (20) is separated such that the electrode interval between the source electrode 13 (23) and the drain electrode 12 (22) is a predetermined interval (FIG. 5A).
[0036]
The side surfaces (end surfaces in the electrode width direction) of both electrodes separated at this time may have irregularities due to the spread of the applied material along the surface of the substrate. For this reason, the side surface of each electrode is irradiated with a laser to remove unnecessary portions, and the electrode width is adjusted to a predetermined width (FIG. 5B).
[0037]
Further, the film thickness is made uniform by irradiating a laser on the curved surface of the upper surface of each electrode generated by applying by ink-jet printing (FIG. 5C). By making such a uniform film thickness not only on the electrodes but also on each layer formed, it becomes possible to make the channel thickness of the finally formed TFTs the same within the same element, in an array form. It is possible to reduce variation in characteristics between the formed TFTs (when the upper surface is a curved surface, the channel thickness differs between the center and the end of the electrode even in the same element). Moreover, the adhesiveness of the organic-semiconductor layer 30 formed later and each electrode can also be improved by making an upper surface into a plane. In order to make the film thickness uniform, the reflectance (or refractive index) of the irradiated laser is observed, and the change point from the curved surface to the flat surface is detected from the numerical change of the reflectance (refractive index). That's fine.
[0038]
The organic semiconductor layer 30 is applied by ink jet printing over the source electrode 13 (23) and the drain electrode 12 (22) formed as described above (FIG. 2C). As the organic semiconductor layer 30, for example, a polymer organic material such as polyphenylene vinylene or polythiophene can be used. The organic semiconductor layer 30 may be doped with a dopant in order to adjust the conductivity.
[0039]
Next, after laser irradiation is performed on the upper surface of the organic semiconductor layer 30 to make the film thickness uniform, a gate insulating layer 40 is formed on the entire surface of the substrate (FIG. 2D). In this way, when the material is applied to the entire surface of the substrate, it is not necessary to use ink jet printing. In this embodiment, the gate insulating layer 40 is applied by spin coating. As the gate insulating layer 40, for example, an organic material such as polyvinylphenol or polyimide can be used.
[0040]
Subsequently, the gate region 41 of the gate insulating layer 40 (region where the source / drain electrodes face each other) is irradiated with a laser, and the thickness of the gate insulating layer 40 in this portion is made uniform. In this step, the contact hole 42 for connecting the source electrode 13 of the switching TFT 1 and the gate electrode 21 of the driving TFT 2 and the source electrode 23 of the driving TFT 2 and the organic EL lower layer electrode formed in the subsequent step A contact hole 43 for connecting to 60 is opened (FIG. 2E). The opening of the gate insulating layer 40 is formed by irradiating the contact hole formation position with a laser to remove the gate insulating layer 40.
[0041]
After the film thickness is uniformed and contact holes are opened as described above, the gate electrodes 11 and 21 and the scanning lines 5 are applied to the gate insulating layer 40 by ink jet printing (FIG. 2F). As the gate electrodes 11 and 12, an organic conductive material such as PEDOT or a material such as aluminum can be used.
[0042]
After the gate electrode is formed, the gate electrodes 11 and 21 are irradiated with laser, and the electrode widths and electrode lengths of the gate electrodes 11 and 21 are predetermined values corresponding to the electrode widths and electrode intervals of the source electrode and the drain electrode. Adjust to.
[0043]
Since the organic TFT produced by the above process is formed by laser irradiation after ink jet printing, the size of each electrode and the electrode spacing of the source / drain electrodes are formed with high accuracy, and the organic semiconductor layer 30, In addition, since variations in the thickness of the gate insulating layer 40 are reduced, variations in device characteristics are reduced.
[0044]
In the present invention, the interface between the organic semiconductor layer 30 and the gate insulating layer 40 can be flattened by laser irradiation. For this reason, the crystallinity of the organic semiconductor layer at the insulating layer interface is improved (increase in grain size and reduction in grain boundaries and intragranular defects), and carrier mobility can be improved. Therefore, the characteristics of the organic TFT such as on-resistance, saturation drain current, and operable frequency can be improved.
[0045]
Subsequently, an organic EL element is formed on the organic TFT array produced as described above. First, the insulating layer 50 is formed on the entire surface of the substrate by spin coating (FIG. 3A). As the insulating layer 50, for example, an organic material such as polyvinylphenol or polyimide can be used as in the gate insulating layer 40.
[0046]
Then, as shown in FIG. 3B, a contact hole 51 for connecting the source electrode 23 of the driving TFT 2 and the organic EL lower layer electrode 60 formed in the next process is opened. This opening may be formed by removing the insulating layer 50 by laser irradiation, like the opening of the gate insulating layer 40.
[0047]
Subsequently, an organic EL lower layer electrode 60 made of ITO or the like is applied on the insulating layer 50 (FIG. 3C). The organic EL lower layer electrode 60 needs to have a pattern in which each pixel is electrically separated. Such a pattern can be formed by applying the entire surface of the substrate by spin coating and then irradiating the laser to remove unnecessary portions, or by applying only to a predetermined position by ink jet printing.
[0048]
On the organic EL lower layer electrode 60 thus formed, an organic light emitting layer 61 made of 8-quinolinol aluminum complex or the like is formed on the entire surface of the substrate by coating (FIG. 3D). Then, the organic EL upper electrode 62 is formed by providing aluminum on the entire surface of the substrate, and the organic EL display device is completed (FIG. 3E).
[0049]
Since the organic EL display device manufactured as described above has a small variation in characteristics of the driving TFT 2, the variation in driving current for driving the organic EL element is small. For this reason, the dispersion | variation in the emitted light intensity of each pixel can also be made small.
[0050]
Moreover, since all the manufacturing steps described above can be performed under atmospheric pressure, the process is very simple.
[0051]
In this embodiment, in order to connect the source electrode 23 of the driving TFT 2 and the organic EL lower layer electrode 60, the contact hole 43 is opened when the gate insulating layer 40 is formed, and the contact hole 51 is opened when the insulating layer 50 is formed. The opening of the contact hole 43 may be omitted, and the insulating layer 50 and the gate insulating layer 40 may be opened collectively when the contact hole 51 is opened.
[0052]
(Second Embodiment)
In the first embodiment, the gate insulating layer 40 is formed on the entire surface of the substrate. However, the gate insulating layer 40 only needs to exist at a necessary portion, and does not need to be formed on the entire substrate. Therefore, in the second embodiment of the present invention, an insulating layer is formed only between the gate electrode 11 (21) and the organic semiconductor layer 30 and between wirings that need to be insulated. Since the other steps are the same as those of the first embodiment, only the schematic diagram of the step of forming the gate insulating layer 40 and the steps before and after that is shown in FIG. 6 shows a top view of each step and a cross-sectional view taken along AA ′ in FIG. 1, as in FIG.
[0053]
Hereinafter, the second embodiment will be described with reference to FIG.
[0054]
As shown in FIG. 6A, the organic semiconductor layer 30 is formed through the same process as in the first embodiment.
[0055]
Then, a gate insulating layer 40 is applied onto the organic semiconductor layer 30 by ink jet printing, and an inter-wiring insulating layer 44 is formed at the intersection of the data line 4 and the power supply line 6 and the scanning line 5 to be formed in a later process. Application is performed by inkjet printing (FIG. 6B). At this time, the application region of the gate insulating layer 40 applied on the organic semiconductor layer 30 is not completely short-circuited between the gate electrode 11 (21) and the organic semiconductor layer 30 formed in the next step. Apply to cover. The gate region 41 of the gate insulating layer 40 thus formed is irradiated with a laser to make the thickness of the gate insulating layer 40 uniform.
[0056]
Then, the gate electrodes 11 and 21 and the scanning line 5 are applied by ink jet printing (FIG. 6C).
[0057]
Subsequent formation and opening of the insulating layer 50, formation of the organic EL lower layer electrode 60, formation of the organic light emitting layer 61, and formation of the organic EL upper layer electrode 62 are performed through the same steps as in the first embodiment, and the organic EL display device Can be obtained.
[0058]
In the second embodiment, the gate insulating layer 40 does not exist in the source electrode 13 of the switching organic TFT 1. For this reason, the opening process (FIG. 2E) of the gate insulating layer 40 required in the first embodiment can be omitted, and the process can be further simplified. Further, since the gate insulating layer 40 is applied only to the minimum necessary, the material cost can be reduced.
[0059]
(Third embodiment)
In the first embodiment, the organic semiconductor layer 30 is formed, and in the second embodiment, the organic semiconductor layer 30 and the gate insulating layer 40 are directly drawn by ink jet printing. Thus, when the material is directly drawn by ink jet printing, the applied liquid material may spread along the substrate surface. Since the spread of such materials depends on the surface state such as unevenness and wettability, the extent varies depending on the application position on the substrate. For this reason, the film thickness of the applied material varies.
[0060]
In the above embodiment, the film thickness variation is reduced by laser irradiation. However, it is preferable to reduce the film thickness variation during coating. Therefore, in the third embodiment, the process of forming the organic semiconductor layer 30 and the gate insulating layer 40 is changed from the first and second embodiments. The manufacturing process of the third embodiment is shown in FIG. 7 shows a top view of each step and a cross-sectional view taken along AA ′ in FIG. 1, as in FIG.
[0061]
The third embodiment will be described below based on FIG.
[0062]
First, after the source / drain electrodes are formed by the same process as the above embodiment (FIG. 7A), the first insulating layer 70 is applied to the entire surface of the substrate by spin coating (FIG. 7B). The film thickness of the first insulating layer 70 is larger than the combined film thickness of the organic semiconductor layer 30 and the gate insulating layer 40 to be applied later.
[0063]
Next, openings 71 and 72 are formed at the formation position of the organic semiconductor layer 30 of the first insulating layer 70. Further, in the same process, a contact hole 73 for connecting the source electrode 13 of the switching TFT 1 and the gate electrode 21 of the driving TFT 2 is also opened (FIG. 7C). A laser may be used to form these openings as in the above embodiment.
[0064]
The organic semiconductor layer 30 is applied and deposited by ink jet printing in the openings 71 and 72 formed as described above (FIG. 7D). At this time, since the organic semiconductor layer 30 is applied only in an amount corresponding to the designed film thickness, the openings 71 and 72 of the insulating layer 70 having a film thickness larger than the designed film thickness of the organic semiconductor layer 30 are completely filled. There is nothing.
[0065]
In this way, the application region of the organic semiconductor layer 30 is limited to the region of the openings 71 and 72. Therefore, the applied material does not spread along the surface, and the film thickness variation depending on the formation position on the substrate is reduced. Further, since the material does not spread along the substrate surface, the shape of the upper surface of the formed pattern is flattened compared to the shape of the upper surface of the pattern drawn directly by ink jet printing. For this reason, it becomes easy to make the film thickness uniform by laser irradiation.
[0066]
Subsequently, after the film thickness of the organic semiconductor layer 30 is made uniform, the gate insulating layer 40 is applied and deposited by ink jet printing on the organic semiconductor layer 30 in the openings 71 and 72 (FIG. 7E). . Also in this case, since the gate insulating layer 40 is applied only in an amount corresponding to the designed film thickness, similarly to the application of the organic semiconductor layer 30, the total thickness of the organic semiconductor layer 30 and the gate insulating layer 40 is larger than the total designed film thickness. The openings 71 and 72 of the insulating layer 70 having the following thickness are not completely filled.
[0067]
In this manner, even when the gate insulating layer 40 is applied, the applied material is limited to the regions of the openings 71 and 72, so that it does not spread along the surface, and variations in film thickness are reduced.
[0068]
After the gate insulating layer 40 is formed as described above, the gate region 41 on the gate insulating layer 40 is irradiated with a laser to make the film thickness uniform. Then, after forming the gate electrodes 11 and 21 and the scanning line 5 (FIG. 7F) and forming the gate electrode by laser irradiation, the formation and opening of the second insulating layer (insulation of the above embodiment) The organic EL display device is formed by sequentially forming the organic EL portion and the organic EL portion.
[0069]
As described above, by forming a pattern by depositing a material in a recessed portion provided in advance, variation in the film thickness of the formed pattern can be reduced. In particular, when two or more layers are formed with the same recess as described above, alignment is also facilitated.
[0070]
In the present embodiment, the method of depositing a material in the concave portion is used for forming the organic semiconductor layer 30 and the gate insulating layer 40. However, the present invention is not limited to this and can be applied to any layer. it can. For example, a recess may be provided in the substrate during electrode formation, and the electrode material may be deposited in the recess.
[0071]
(Fourth embodiment)
In each of the above-described embodiments, the pattern of each electrode of the organic TFT is formed with high accuracy by shaping by laser irradiation. However, in each organic TFT, the relative position of the gate electrode 11 (21) with respect to the source electrode 13 (23) and the drain electrode 12 (22) is aligned when the gate electrode 11 (21) is applied by inkjet printing. It depends only on accuracy. Therefore, in the fourth embodiment, the source / drain electrodes are formed simultaneously with the opening of the first insulating layer 70 in the third embodiment, and the organic semiconductor layer 30 and the gate insulation are formed in the opening 71 (72). Layer 40 and gate electrode 11 (21) are deposited and aligned.
[0072]
The manufacturing process of the fourth embodiment is shown in FIG. 8 shows a top view of each step and a cross-sectional view taken along AA ′ in FIG. 1, as in FIG.
[0073]
The fourth embodiment will be described below based on FIG.
[0074]
First, the electrodes 10, 20, the data line 4, and the power supply line 6 are applied on the substrate 100 by ink jet printing, and after adjusting the electrode width of the TFT forming portion and making the film thickness uniform by laser irradiation ( 8A), the first insulating layer 70 is applied over the entire surface of the substrate by spin coating (FIG. 7B). The film thickness of the first insulating layer 70 is larger than the total film thickness of the designed film thickness of the organic semiconductor layer 30, the gate insulating layer 40, and the gate electrode 11 (21) to be applied later.
[0075]
Next, the TFT formation position of the first insulating layer 70 is irradiated with a laser to form openings 71 and 72, and at the same time, the electrode 10 (20) is separated at a predetermined interval to separate the source electrode 13 (23). Then, the drain electrode 12 (22) is formed (FIG. 8C). In this step, the contact hole 73 is formed as in the third embodiment.
[0076]
In the openings 71 and 72 formed as described above, the organic semiconductor layer 30 and the gate insulating layer 40 are deposited by the same process as in the third embodiment (FIGS. 8D and 8E). .
[0077]
Subsequently, the gate region 41 on the gate insulating layer 40 is irradiated with a laser to make the film thickness uniform, and then the gate electrodes 11 and 21 and the scanning line 5 are applied by inkjet printing (FIG. 8F). ). At this time, the material applied to the openings 71 and 72 is deposited in the openings.
[0078]
As described above, the gate electrode 11 (21) on the gate region 41 of the organic TFT is formed to be limited to the region of the opening 71 (72) and is self-aligned with the source / drain electrodes. Aligned. For this reason, the relative positional relationship of each electrode becomes the same in all TFTs, and the characteristic variation of each organic TFT on the substrate can be further reduced.
[0079]
When the gate electrodes 11 and 21 are applied, the gate electrode 11 is applied so as to be connected to the scanning line 5 and the gate electrode 21 is connected to the source electrode 13, respectively. , 21 are formed. Since this step may cause disconnection of the electrode, it is preferable to make the step portion to which the gate electrode is applied small in the step of making the thickness of the gate insulating layer 40 uniform.
[0080]
After forming the gate electrodes 11 and 21 and the scanning line 5 as described above, as in the third embodiment, the gate electrode insulating layer 50 is formed and the opening and the organic EL element portion are formed, and an organic EL display is formed. Forming device.
[0081]
As described above, according to the present embodiment, it is possible to form organic TFTs with smaller variations than in the above embodiments, and it is also possible to reduce the variation in light emission of the organic EL display device.
[0082]
(Fifth embodiment)
In each of the above-described embodiments, the organic TFT in which the source electrode 13 (23) and the drain electrode 12 (22) are below the gate electrode 11 (21) is formed. However, the effect of the present invention is not limited to the organic TFT having this structure. Therefore, in the fifth embodiment, a case where the present invention is applied to an organic TFT having a structure in which the gate electrode 11 (21) is below the source electrode 13 (23) and the drain electrode 12 (22) is based on FIG. explain. FIG. 9 shows a top view of each process and a cross-sectional view between AA ′ in FIG.
[0083]
First, the gate electrodes 11 and 12 and the scanning line 5 are applied on the substrate 100 by ink jet printing (FIG. 9A). The gate electrodes 11 and 12 are irradiated with a laser to have a predetermined size as in the above embodiments.
[0084]
Next, after the gate insulating layer 40 is applied over the entire surface of the substrate 100 by spin coating (FIG. 9B), the gate electrode 21 of the driving TFT 2 and the source electrode 13 of the switching TFT 1 to be formed later are connected. The contact hole 42 is opened by laser irradiation (FIG. 9C).
[0085]
Subsequently, the electrodes 10 and 20, the data line 4, and the power supply line 6 are applied by inkjet printing (FIG. 9D). Then, the electrodes 10 and 20 are separated by laser irradiation to form source electrodes 13 and 23 and drain electrodes 12 and 22 (FIG. 9E). In the present embodiment, the electrodes 10 and 20 are separated by laser irradiation, and at the same time, the thickness of the gate region 41 on the gate insulating layer 40 is made uniform.
[0086]
The organic semiconductor layer 30 is applied over the source electrode 13 (23) and the drain electrode 12 (22) thus formed, and the film thickness is made uniform by laser irradiation (FIG. 9F).
[0087]
Subsequent formation of the insulating layer 50, opening, and formation of the organic EL element portion are the same as those in the above embodiments.
[0088]
The organic TFT formed as described above has a small variation in the characteristics of each element, as in the first embodiment. In addition, since the organic EL display device is driven by an organic TFT having a small characteristic variation, the variation in driving current of each pixel is small, and a uniform light emission intensity can be obtained.
[0089]
Although the case where the gate insulating layer 40 is applied to the entire surface of the substrate by spin coating has been described in the present embodiment, the data line between the gate electrode 11 (21) and the organic semiconductor layer 30 is provided as in the second embodiment. 4 and the intersection of the power supply line 6 and the scanning line 5 may be applied by ink jet printing.
[0090]
In each of the above embodiments, the lower electrode of the organic EL element is a transparent electrode and light is extracted from the lower surface (organic TFT side). However, a negative potential is applied to the power supply line 6 and the data line 4 and the polarity of the signal applied to the scanning line 5 are also inverted, and the organic EL lower layer electrode 60 is replaced with a metal electrode made of Al, and the organic EL upper layer electrode is replaced with a transparent electrode made of ITO, etc. It is good also as a structure which takes out.
[0091]
Moreover, although the organic light emitting layer 61 of the organic EL element part was demonstrated as a single layer structure, the multilayer structure provided with the positive hole transport layer and the electron supply layer may be sufficient, and the material used for an organic light emitting layer by the production position of a pixel The color display may be made by changing the color so that RGB can be developed.
[0092]
In addition, the material of each layer used in each of the above embodiments is merely a specific example, and does not limit the technical scope of the present invention. Further, in each of the above embodiments, the manufacturing method of the active matrix display device including only the active elements of the organic TFT and the organic EL element as the constituent elements has been described. However, the present invention is not limited to this. A resistor composed of the layer 30 and a passive element such as an MIM capacitor using the gate insulating layer 40 or the first insulating layer 70 can also be formed.
[0093]
Furthermore, the material application method by ink jet printing using Coulomb force has been described only in the first embodiment, but it is needless to say that the method can be appropriately used in the process using ink jet printing of each embodiment.
[0094]
Furthermore, in each of the above embodiments, the application by spin coating has been described in the case where the material is applied to the entire surface of the substrate. However, the present invention is not limited to this, and screen printing or the like may be used.
[0095]
【The invention's effect】
As described above, according to the present invention, since the process is only a process under atmospheric pressure, the organic transistor and the organic EL display device can be manufactured at a lower cost.
[0096]
In addition, since the liquid material applied by inkjet printing is guided to the design position in a self-aligning manner by the Coulomb force, the pattern can be formed with high accuracy.
[0097]
And since a liquid material is deposited by the ink-jet printing in the recessed part provided beforehand, a pattern can be formed with a sufficient precision and thickness variation can be reduced.
[0098]
Further, after forming a pattern by applying a liquid material by ink jet printing, forming is performed by irradiating a laser, and thus an organic transistor with small characteristic variation can be manufactured.
[0099]
In addition, since driving is performed using an organic transistor with small variation in characteristics, an organic EL display device that emits light uniformly can be manufactured.
[Brief description of the drawings]
FIG. 1 is a top view showing an organic EL display device to which the present invention is applied.
FIGS. 2A and 2B are a top view and a cross-sectional view showing a method of manufacturing the organic TFT according to the first embodiment of the invention. FIGS.
FIGS. 3A and 3B are a top view and a cross-sectional view showing a method for manufacturing the organic EL element according to the first embodiment of the invention. FIGS.
FIG. 4 is an explanatory diagram showing ink jet printing by charge application according to the present invention.
FIG. 5 is an explanatory view showing pattern formation by laser irradiation according to the present invention.
6A and 6B are a top view and a cross-sectional view showing a manufacturing method according to the second embodiment of the present invention.
7A and 7B are a top view and a cross-sectional view showing a manufacturing method according to the third embodiment of the present invention.
8A and 8B are a top view and a cross-sectional view showing a manufacturing method according to the fourth embodiment of the present invention.
FIGS. 9A and 9B are a top view and a cross-sectional view showing a manufacturing method according to a fifth embodiment of the invention. FIGS.
FIG. 10 is a cross-sectional view showing a conventional organic transistor
[Explanation of symbols]
1 Switching TFT
2 Driving TFT
4 data lines
5 scanning lines
6 Power supply line
11, 21, 91 Gate electrode
12, 22, 92 Drain electrode
13, 23, 93 Source electrode
30, 94 Organic semiconductor layer
40, 95 Gate insulation layer
44 Insulation layer between wires
50 Insulating layer
60 Organic EL lower layer electrode
61 Organic light emitting layer
62 Organic EL upper layer electrode
70 first insulating layer
100 substrates
101 Inkjet nozzle
102, 103 laser
104 Liquid material

Claims (14)

In a method for producing an organic transistor, which is a member constituting an organic transistor, and formed of at least one of an electrode, a semiconductor layer , and an insulating layer made of a pattern having a predetermined shape on a substrate by inkjet printing,
Applying a charge to a predetermined position where the pattern on the application target surface of inkjet printing is to be formed ;
Applying a charge of the opposite polarity to the charge to the pattern forming material applied by ink jet printing ;
Applying the material to which the charge has been applied to the surface to be coated after the charge has been applied;
Self the pattern was derived by a Coulomb force the material applied charge is applied to the portion where charges are applied on the application target surface composed of the material to the predetermined position on the application target surface a step of formed,
A method for producing an organic transistor, comprising:   The method for producing an organic transistor according to claim 1, wherein a charge is applied to the predetermined position by laser irradiation.   The manufacturing method of the organic transistor of Claim 1 or Claim 2 which provides an electric charge to the said material by laser irradiation. Further comprising the step of forming a recess at the predetermined position before the step of applying a charge to the predetermined position of the application target surface;
In the step of forming the pattern at a predetermined position on the application target surface in a self-aligning manner , the applied material is deposited on a portion of the application target surface where the concave portion is formed and a charge is applied. 2. The method of manufacturing an organic transistor according to claim 1, wherein the pattern made of the material is guided by a Coulomb force while being self-aligned at the predetermined position on the surface to be coated.   The method for producing an organic transistor according to claim 4, wherein the recess is formed by laser irradiation.   The method for producing an organic transistor according to claim 1, further comprising a step of irradiating the formed pattern with a laser and forming the pattern with higher accuracy after the pattern is formed at a predetermined position.   The formed pattern is an electrode pattern, and in the step of forming the formed pattern with higher accuracy, a source electrode having a predetermined electrode interval by separating the electrode pattern to be irradiated with the laser, and The method for producing an organic transistor according to claim 6, wherein the organic transistor is a drain electrode.   The organic transistor manufacturing method according to claim 6, wherein the pattern width of the pattern to be irradiated with the laser is adjusted to a predetermined width in the step of forming the formed pattern with higher accuracy.   The method of manufacturing an organic transistor according to claim 6, wherein the film thickness of the pattern to be irradiated with the laser is adjusted to a predetermined thickness in the step of forming the formed pattern with higher accuracy. Is a member constituting the organic transistor, the electrode and the semiconductor layer made of a pattern of a predetermined shape, in the manufacturing method of an organic transistor that form in order on a substrate by ink jet printing,
Applying an electrode on the substrate;
Separating the electrode applied on the substrate by irradiating a predetermined position of the electrode with a laser to form a source electrode and a drain electrode having a predetermined electrode interval;
Applying a semiconductor layer between the source electrode and the drain electrode;
Forming a gate insulating layer on the semiconductor layer;
Applying a gate electrode on the gate insulating layer;
Have
At least one of the steps of applying an electrode on the substrate, applying the semiconductor layer, and applying the gate electrode;
Applying a charge to a predetermined position where the pattern on the application target surface of inkjet printing is to be formed ;
Applying a charge of the opposite polarity to the charge to the pattern forming material applied by ink jet printing ;
Applying the material to which the charge has been applied to the surface to be coated after the charge has been applied;
Self the pattern was derived by a Coulomb force the material applied charge is applied to the portion where charges are applied on the application target surface composed of the material to the predetermined position on the application target surface a step of formed,
A method for producing an organic transistor, comprising: Is a member constituting the organic transistor, the electrode and the semiconductor layer made of a pattern of a predetermined shape, in the manufacturing method of an organic transistor that form in order on a substrate by ink jet printing,
Applying a gate electrode on the substrate;
Forming a gate insulating layer on the gate electrode;
Applying an electrode on the gate insulating layer;
Separating the electrode applied on the gate insulating film by irradiating a predetermined position of the electrode with a laser to form a source electrode and a drain electrode having a predetermined electrode interval;
Applying a semiconductor layer between the source electrode and the drain electrode;
Have
At least one of the steps of applying a gate electrode, applying the electrode on the gate insulating layer, and applying the semiconductor layer;
Applying a charge to a predetermined position where the pattern on the application target surface of inkjet printing is to be formed ;
Applying a charge of the opposite polarity to the charge to the pattern forming material applied by ink jet printing ;
Applying the material to which the charge has been applied to the surface to be coated after the charge has been applied;
Self the pattern was derived by a Coulomb force the material applied charge is applied to the portion where charges are applied on the application target surface composed of the material to the predetermined position on the application target surface a step of formed,
A method for producing an organic transistor, comprising: The gate insulating layer is applied in a self-aligned manner by applying, by inkjet printing, a material for forming a gate insulating layer having a charge of opposite polarity to a predetermined position to which the gate insulating layer is to be formed. The method for producing an organic transistor according to claim 10 or 11, which is formed .   The method of manufacturing an organic transistor according to any one of claims 10 to 12, further comprising a step of irradiating the semiconductor layer, the gate insulating layer, or the gate electrode with a laser to form the semiconductor layer with higher accuracy. In a manufacturing method of an active matrix type organic EL display device including an organic transistor,
After the organic transistor is formed by the method of manufacturing an organic transistor according to any one of claims 10 to 13,
Forming a wiring connected to the address indicating circuit;
Forming an organic EL lower layer electrode;
Forming an organic light emitting layer on the organic EL lower layer electrode;
Forming an organic EL upper layer electrode on the organic light emitting layer;
The manufacturing method of the organic electroluminescence display which has this.

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