KR100626050B1 - Organic thin film transistor, organic thin film transistor array, flat panel display device therewith and method of manufacturing the organic thin film transistor array - Google Patents

Abstract

The present invention provides an organic thin film transistor, an organic thin film transistor array, a flat panel display device including the organic thin film transistor or the organic thin film transistor array, and a method of manufacturing the organic thin film transistor array, which have a simple manufacturing process and a low manufacturing cost, and have high yields. For this purpose, a substrate, a source electrode and a drain electrode provided on the substrate, an end portion of the source electrode in the direction of the drain electrode and an end portion of the drain electrode in the direction of the source electrode are exposed so as to be exposed. And a first insulating film covering the electrode, an organic semiconductor layer in contact with the source electrode and the drain electrode, a second insulating film covering the organic semiconductor layer, and a gate electrode provided on the second insulating film. Organic thin film transistor It provides a thin film transistor array, a method of manufacturing a flat panel display device and the organic thin film transistor array having the organic thin film transistor or the organic thin film transistor array.

Description

Organic thin film transistor, organic thin film transistor array, flat panel display device including the organic thin film transistor or the organic thin film transistor array, and a method of manufacturing the organic thin film transistor array therewith and method of manufacturing the organic thin film transistor array}

1 is a cross-sectional view schematically showing a conventional staggered organic thin film transistor.

2 is a cross-sectional view schematically showing a staggered organic thin film transistor according to a preferred embodiment of the present invention.

3 is a cross-sectional view schematically showing an organic thin film transistor according to another preferred embodiment of the present invention.

4 is a cross-sectional view schematically showing an organic thin film transistor according to another preferred embodiment of the present invention.

5 is a cross-sectional view schematically showing an organic thin film transistor according to another preferred embodiment of the present invention.

6 is a cross-sectional view schematically showing an organic thin film transistor according to another preferred embodiment of the present invention.

7 is a schematic cross-sectional view of an organic thin film transistor array according to another exemplary embodiment of the present invention.

8 is a cross-sectional view schematically showing an organic thin film transistor array according to another preferred embodiment of the present invention.

9 is a cross-sectional view schematically showing an organic thin film transistor array according to another preferred embodiment of the present invention.

10 is a cross-sectional view schematically showing an organic thin film transistor array according to another preferred embodiment of the present invention.

11 to 18 are cross-sectional views schematically illustrating a manufacturing process of an organic thin film transistor array according to an exemplary embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

110: substrate 120: source electrode

130: drain electrode 150: first insulating film

160: organic semiconductor layer 170: second insulating film

180: gate electrode

The present invention relates to an organic thin film transistor, an organic thin film transistor array, a flat panel display device having the organic thin film transistor or the organic thin film transistor array, and a method of manufacturing the organic thin film transistor array. The present invention relates to an organic thin film transistor, an organic thin film transistor array, a flat panel display device including the organic thin film transistor or the organic thin film transistor array, and a method of manufacturing the organic thin film transistor array.

After the development of polyacetylene, a conjugated organic polymer exhibiting semiconductor characteristics, the characteristics of organic matters, that is, various synthetic methods and easy molding into fibers or films, and advantages such as flexibility, conductivity, and low production cost Research into transistors using organic materials has been actively conducted in a wide range of fields such as functional electronic devices and optical devices.

In the case of a conventional silicon thin film transistor having a semiconductor layer formed of silicon, it has a semiconductor layer having a source region and a drain region doped with a high concentration of impurities and a channel region formed between the two regions. And a gate electrode insulated from the semiconductor layer and positioned in a region corresponding to the channel region, and a source electrode and a drain electrode in contact with the source region and the drain region, respectively.

However, the conventional silicon thin film transistor having the above structure has a problem such as high manufacturing cost, easily broken by external impact, and cannot be used because it is produced by a high temperature process of 300 ° C. or higher.

In particular, a flat panel display device such as a liquid crystal display device (LCD) or an electroluminescence display device (ELD) is used as a switching element for controlling the operation of each pixel and a thin film transistor as a driving element of each pixel. In order to satisfy the flexible and characteristic that is recently required in such a flat panel display device, attempts are being made to use a substrate provided with a plastic material instead of a conventional glass material. However, when using a plastic substrate, it is necessary to use a low temperature process rather than a high temperature process as described above. Therefore, there is a problem that it is difficult to use a conventional silicon thin film transistor.

On the other hand, when the organic film is used as the semiconductor layer of the thin film transistor, these problems can be solved. Recently, researches on organic thin film transistors using the organic film as the semiconductor layer have been actively conducted.

1 is a cross-sectional view schematically showing a conventional staggered type organic thin film transistor. Referring to FIG. 1, a source electrode 20 and a drain electrode 30 are provided on a substrate 10, and an organic semiconductor layer 60 in contact with the source electrode 20 and the drain electrode 30 is provided. The gate insulating layer 70 is provided on the organic semiconductor layer 60, and the gate electrode 80 is provided on the organic semiconductor layer 60.

In the structure as described above, the end of the gate electrode 80 overlaps with the end of the source electrode 20 and the end of the drain electrode 30, and if not overlapped with the organic semiconductor layer 60. This is because the channel formed may not be connected to the source electrode 20 and the drain electrode 30. However, when the gate electrode 80 overlaps with the source electrode 20 or the drain electrode 30, parasitic capacitance becomes large. Therefore, there is a problem that the end of the gate electrode 80 should be exactly overlapped with the end of the source electrode 20 and the end of the drain electrode 30.

In addition, when fabricating an organic thin film transistor array including a plurality of conventional organic thin film transistors as shown in FIG. 1, a means for preventing crosstalk between the organic thin film transistors should be provided. There is a problem that it is difficult to cleanly pattern the organic semiconductor layer using a photoresist or the like.

In addition, there is a problem in that a mask must be used several times in order to manufacture an organic thin film transistor having a structure as shown in FIG. 1 through deposition or the like.

The present invention is to solve the various problems including the above problems, the organic thin film transistor, the organic thin film transistor array, the organic thin film transistor or the organic thin film transistor array having a simple manufacturing process, low manufacturing cost and high yield. An object of the present invention is to provide a flat panel display device and a method of manufacturing the organic thin film transistor array.

In order to achieve the above object and various other objects, the present invention provides a substrate, a source electrode and a drain electrode provided on the substrate, an end portion of the source electrode in the direction of the drain electrode and the drain electrode. A first insulating film covering the source electrode and the drain electrode, an organic semiconductor layer in contact with the source electrode and the drain electrode, a second insulating film covering the organic semiconductor layer, such that an end portion of the source electrode direction is exposed; and Provided is an organic thin film transistor comprising a gate electrode provided on an upper portion of the second insulating layer.

According to such another feature of the present invention, the substrate may be a transparent substrate.

According to still another feature of the present invention, the first insulating film may be a photoresist.

According to another feature of the invention, the organic semiconductor layer may be provided to cover the first insulating film.

According to still another feature of the present invention, the organic semiconductor layer may be provided between an end portion of the source electrode in the direction of the drain electrode and an end portion of the drain electrode in the direction of the source electrode.

According to another feature of the invention, the second insulating film may be provided to cover the first insulating film.

According to still another feature of the present invention, the gate electrode may be provided to cover the second insulating film.

According to still another feature of the present invention, the gate electrode may be provided so as to correspond to an area between an end portion of the source electrode in the direction of the drain electrode and an end portion of the drain electrode in the direction of the source electrode.

According to still another feature of the present invention, at least one of a direction opposite to the drain electrode direction of the source electrode and a direction opposite to the source electrode direction of the drain electrode is on the same plane as the source electrode and the drain electrode. The isolation wall provided may be further provided.

According to another feature of the invention, the separating wall may be formed of a material that blocks ultraviolet rays.

According to still another feature of the present invention, the separating wall may be a nitride film.

In order to achieve the above object, the present invention also provides a substrate, a plurality of pairs of source and drain electrodes provided on the substrate, and an end portion in a direction of a drain electrode corresponding to the source electrode of each of the source electrodes. And a first insulating layer covering the source electrodes and the drain electrodes so that an end portion of the respective drain electrodes in a direction corresponding to the drain electrode is exposed, the exposed ends of the source electrodes and the exposed electrodes of the drain electrodes. And an organic semiconductor layer in contact with an end portion, a second insulating film covering the organic semiconductor layer, and gate electrodes provided on an upper portion of the second insulating film and corresponding to each pair of the source and drain electrodes. An organic thin film transistor array is provided.

According to such another feature of the present invention, the substrate may be a transparent substrate.

According to still another feature of the present invention, the first insulating film may be a photoresist.

According to another feature of the invention, the isolation wall may be further provided between the pair of the source electrode and the drain electrode.

According to another feature of the invention, the isolation walls may be formed of a material that blocks ultraviolet rays.

According to another feature of the invention, the separating walls may be a nitride film.

According to still another feature of the present invention, the organic semiconductor layer may be provided over the entire surface of the substrate.

According to another feature of the invention, the organic semiconductor layer may be provided so as to correspond to each pair of the source electrode and the drain electrode.

The present invention also provides a flat panel display device comprising the above organic thin film transistor in order to achieve the above object.

The present invention also provides a flat panel display device comprising the above organic thin film transistor array in order to achieve the above object.

In order to achieve the above object, the present invention also provides a method of forming a plurality of pairs of source and drain electrodes on top of a substrate, and applying a positive photoresist to cover the source and drain electrodes. Irradiating ultraviolet rays to the photoresist through the substrate, developing the photoresist, and forming an end portion in a direction of a drain electrode corresponding to the source electrode of each of the source electrodes and of each of the drain electrodes. Exposing an end portion in a direction of a source electrode corresponding to the drain electrode; forming an organic semiconductor layer in contact with the exposed end of each source electrode and the exposed end of the drain electrode corresponding to the source electrode; Forming a second insulating film to cover the organic semiconductor layer, and on top of the second insulating film, It provides a method of manufacturing an organic thin film transistor array comprising the step of forming the gate electrodes to correspond to the pair of the respective source electrode and drain electrode.

According to such another feature of the present invention, the substrate may be a transparent substrate.

According to another feature of the invention, forming a plurality of pairs of source and drain electrodes on top of the substrate, and applying a positive photoresist to cover the source and drain electrodes The method may further include forming isolation walls between the pair of the source electrode and the drain electrode.

According to still another aspect of the present invention, the method may further include forming a plurality of isolation walls on the substrate, before forming the pair of source and drain electrodes on the substrate. Forming a plurality of pairs of the source electrode and the drain electrode on the upper portion, may be a step of forming a pair of source electrode and drain electrode in each space between the separation walls.

According to another feature of the invention, the isolation walls may be formed of a material that blocks the ultraviolet rays.

According to another feature of the invention, the separating walls may be a nitride film.

According to another feature of the invention, the step of forming an organic semiconductor layer in contact with the exposed end of each source electrode and the exposed end of the drain electrode corresponding to the source electrode, respectively, using a spin coating method It may be a step of forming a layer.

According to another feature of the invention, the step of forming an organic semiconductor layer in contact with the exposed end of each of the source electrode and the exposed end of the drain electrode corresponding to the source electrode, respectively, the material forming the organic semiconductor layer It may be a step of forming an organic semiconductor layer by dropping between the source electrode and the drain electrode corresponding to the source electrode by an inkjet printing method.

According to another feature of the invention, the step of forming the gate electrodes on the upper portion of the second insulating film so as to correspond to the pair of the source and drain electrodes, through the deposition using a mask, the upper portion of the second insulating film The gate electrodes may be formed to correspond to the pairs of the source and drain electrodes.

According to still another aspect of the present invention, the forming of the gate electrodes on the second insulating layer so as to correspond to the pair of the source and drain electrodes includes: forming a gate electrode layer to cover the second insulating layer; And patterning the gate electrode layer to form gate electrodes to correspond to the pairs of the source and drain electrodes.

According to another feature of the invention, the step of forming an organic semiconductor layer in contact with the exposed end of each source electrode and the exposed end of the drain electrode corresponding to the source electrode, respectively, using a spin coating method Forming a layer, and forming the gate electrodes to correspond to the pairs of the source and drain electrodes by patterning the gate electrode layer, simultaneously patterning the gate electrode layer and the organic semiconductor layer, respectively, The gate electrodes and the patterned organic semiconductor layer may be formed to correspond to the pair of drain electrodes.

According to another feature of the present invention, the forming of the gate electrodes to correspond to the pair of the source electrode and the drain electrode on the second insulating layer, the material forming the gate electrode, the source electrode and the drain electrode The gate electrode may be formed by dropping an inkjet printing method on the second insulating layer so as to correspond to the pair of.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a cross-sectional view schematically showing a staggered organic thin film transistor according to a first preferred embodiment of the present invention.

Referring to FIG. 2, a source electrode 120 and a drain electrode 130 are provided on the substrate 110. Various substrates may be used as the substrate 110. In particular, as described in the description of the organic thin film transistor according to the fifth embodiment, a transparent substrate may be used to enable back exposure in a manufacturing process. It is preferable to use.

The source electrode 120 and the drain electrode 130 may be provided on the same plane. The source electrode 120 and the drain electrode 130 are exposed so that an end portion of the source electrode 120 in the direction of the drain electrode 130 and an end portion of the drain electrode 130 in the direction of the source electrode 120 are exposed. ) Is provided with a first insulating film 150. As described later in the manufacturing process, the first insulating layer 150 may be formed of a photoresist, particularly a positive photoresist. The method of forming the first insulating film 150 of the above-described form is described in detail in the description of the organic thin film transistor according to the fifth embodiment described later.

In this case, an exposed portion of the source electrode 120 and the drain electrode 130 that is in contact with the source electrode 120 and the drain electrode 130, more precisely, is not covered by the first insulating layer 150. The organic semiconductor layer 160 is in contact with each other. As shown in FIG. 2, the organic semiconductor layer 160 may be provided over the entire surface of the substrate 110. This can be formed using a spin coating method. That is, after the organic material forming the organic semiconductor layer is dropped on the first insulating film 150, the substrate 110 is rotated so that the organic material is formed on the entire surface of the substrate 110 by the centrifugal force. It may be provided over the entire surface of the insulating film 150.

A second insulating layer 170 is formed to cover the organic semiconductor layer 160, and a gate electrode 180 is provided on the second insulating layer 170. The gate electrode 180 may be formed by various methods, such as an inkjet printing method or a deposition method. In this case, as shown in FIG. 2, the gate electrode 180 may be provided even on the source electrode 120 and the drain electrode 130.

As described above, in the case of the conventional organic thin film transistor, the end of the gate electrode is overlapped with the end of the source electrode and the end of the drain electrode, which is a channel formed in the organic semiconductor layer by the gate electrode if not overlapping. This is because it may not be connected to the source electrode and the drain electrode. However, when the gate electrode overlaps the source electrode or the drain electrode, the parasitic capacitance becomes large. There is a problem that the end of the gate electrode should be exactly overlapped only with the end of the source electrode and the end of the drain electrode.

However, in the organic thin film transistor according to the present exemplary embodiment, the first insulating layer 150 is provided on the source electrode 120 and the drain electrode 130, so that the gate electrode 180 is formed on the source electrode. Even if the area overlapping the 120 and the drain electrode 130 becomes large, the parasitic capacitance may be reduced by the thickness of the first insulating layer 150. In general, as the distance between two metals increases, the capacitance decreases. Therefore, the end of the gate electrode does not need to be exactly overlapped with only the end of the source electrode and the end of the drain electrode, so that the manufacturing process is easy and the yield can be improved.

3 is a cross-sectional view schematically showing an organic thin film transistor according to a second exemplary embodiment of the present invention.

Referring to FIG. 3, the source electrode 220 and the drain electrode 230 are provided on the substrate 210. Various substrates may be used as the substrate 210. As described above in the description of the organic thin film transistor according to the fifth embodiment, a transparent substrate is used to enable back exposure in the manufacturing process. It is desirable to.

The source electrode 220 and the drain electrode 230 may be provided on the same plane. The source electrode 220 and the drain electrode 230 are exposed such that an end portion of the source electrode 220 in the direction of the drain electrode 230 and an end portion of the drain electrode 230 in the direction of the source electrode 220 are exposed. ) Is provided with a first insulating film 250. As described later, the first insulating layer 250 may be formed of a photoresist, particularly a positive photoresist. The method of forming the first insulating film 250 of the above-described form is described in detail in the description of the organic thin film transistor according to the fifth embodiment described later.

Meanwhile, exposed portions of the source electrode 220 and the drain electrode 230 that are in contact with the source electrode 220 and the drain electrode 230, more precisely, are not covered by the first insulating layer 250. An organic semiconductor layer 260 in contact with each part is provided. The second insulating layer 270 covering the organic semiconductor layer 260 is provided on the organic semiconductor layer 260, and the gate electrode 280 is provided on the second insulating layer 270.

The organic thin film transistor according to the present embodiment differs from the organic thin film transistor according to the above-described embodiment in that the organic semiconductor layer 260 is not provided over the entire surface of the substrate 210, but the source electrode 220. And between the drain electrode 230, more precisely between an end portion of the source electrode 220 in the direction of the drain electrode 230 and an end portion of the drain electrode 230 in the source electrode direction 220. . This can be accomplished using an inkjet printing method or the like.

The second insulating layer 270 covering the organic semiconductor layer 260 also has an opening in the first insulating layer 250, that is, an end portion of the source electrode 220 in the direction of the drain electrode 230 and the drain electrode. It may be provided between the end portion of the 230 in the direction of the source electrode 220. The gate electrode 280 may also be formed between an end portion of the source electrode 220 in the direction of the drain electrode 230 and an end portion of the drain electrode 230 in the direction of the source electrode 220 by using an inkjet printing method. It can be provided.

By taking the above structure, the channel to be formed in the organic semiconductor layer 260 by the gate electrode 280 is prevented from being connected to the source electrode 220 and the drain electrode 230. In addition, the parasitic capacitance may be reduced by reducing an area where the gate electrode 280 overlaps with the source electrode 220 and the drain electrode 230. In addition, when fabricating an organic thin film transistor array in which a plurality of organic thin film transistors are listed, the gate electrodes are inevitably patterned. Thus, the gate electrodes may be naturally patterned by the above structure.

Of course, like the organic thin film transistor according to the third exemplary embodiment illustrated in FIG. 4, only the organic semiconductor layer 360 may have an end portion in the direction of the drain electrode 330 of the source electrode 320 and the source of the drain electrode 330. The second insulating layer 370 and the gate electrode 380 may be provided between the end portions of the electrode 320 in the direction of the electrode 320. In addition, like the organic thin film transistor according to the fourth exemplary embodiment illustrated in FIG. 5, the organic semiconductor layer 460 and the second insulating layer 470 are provided over the entire surface of the substrate 410, and the gate electrode is a source electrode ( Various modifications are possible, for example, between the end portion of the drain electrode 430 in the direction of the drain electrode 430 and the end portion of the drain electrode 430 in the direction of the source electrode 420. The same is true in the embodiments to be described later.

6 is a cross-sectional view schematically showing an organic thin film transistor according to a fifth exemplary embodiment of the present invention.

Referring to FIG. 6, a source electrode 520 and a drain electrode 530 are provided on the substrate 510. Various substrates may be used as the substrate 510. As described below, it is preferable to use a transparent substrate to enable back exposure in a manufacturing process.

The source electrode 520 and the drain electrode 530 may be provided on the same plane. The source electrode 520 and the drain electrode 530 are exposed so that an end portion of the source electrode 520 in the direction of the drain electrode 530 and an end portion of the drain electrode 530 in the direction of the source electrode 520 are exposed. ) Is provided with a first insulating film 550. As described later, the first insulating layer 550 may be formed of a photoresist, particularly a positive photoresist. A method of forming the first insulating film 550 of the above type will be described later.

Meanwhile, exposed portions of the source electrode 520 and the drain electrode 530 that are in contact with the source electrode 520 and the drain electrode 530, more precisely, are not covered by the first insulating layer 550. The organic semiconductor layer 560 is provided in contact with each other. A second insulating layer 570 is formed on the organic semiconductor layer 560 to cover the organic semiconductor layer 560, and a gate electrode 580 is provided on the second insulating layer 570.

The organic thin film transistor according to the present exemplary embodiment differs from the organic thin film transistors according to the above-described embodiments in the opposite direction to the drain electrode 530 of the source electrode 520 and the drain electrode 530. In at least one of the opposite directions of the source electrode 520 direction, an isolation wall 540 is further provided on the same plane as the source electrode 520 and the drain electrode 530. In the organic thin film transistor according to the present exemplary embodiment illustrated in FIG. 6, isolation walls 540 are provided at both sides.

As described in more detail in the method of manufacturing an organic thin film transistor array, which will be described later, a photoresist is formed on the entire surface of the substrate 510 to manufacture the first insulating layer 550 having the shape described above. Ultraviolet rays are irradiated to the photoresist through 510.

Irradiating ultraviolet rays to the photoresist through the substrate 510 means that ultraviolet rays are irradiated on the opposite side of the surface on which the source electrode 520 and the drain electrode 530 of the substrate 510 are formed. Means that. The ultraviolet rays reach the photoresist through the transparent substrate 510. In this case, since the ultraviolet light cannot penetrate the source electrode 520 and the drain electrode 530, the ultraviolet light reaches only the photoresist of the region between the source electrode 520 and the drain electrode 530. .

Therefore, when the positive photoresist is used, the coupling of the photoresist in the region between the source electrode 520 and the drain electrode 530 is weakened. Therefore, when this is developed, only photoresists in a region between the source electrode 520 and the drain electrode 530, which are weakened in coupling, are removed, and thus the end and the drain of the source electrode 520 in the direction of the drain electrode 530 are removed. The first insulating layer 550 is formed to cover the source electrode 520 and the drain electrode 530 so that an end portion of the electrode 530 in the direction of the source electrode 520 is exposed.

At this time, the photoresist in the region where the source electrode 520 and the drain electrode 530 which do not block the ultraviolet rays are all removed, and thus the source electrode 520 and the drain electrode 530 are removed. In addition to the region therebetween, photoresist is also removed in the region in the direction opposite to the drain electrode 530 of the source electrode 520 and in the region opposite to the source electrode 520 of the drain electrode 530. Will be. Therefore, by providing the isolation wall 540 formed of a material blocking the ultraviolet rays in the region, it is possible to prevent the photoresist of the region is removed. Any material that does not block UV light may be used as the material of the isolation wall 540, in particular, a nitride film or the like may be used.

7 is a schematic cross-sectional view of an organic thin film transistor array according to a sixth exemplary embodiment of the present invention.

Referring to FIG. 7, pairs 691, 692, and 693 of a plurality of source and drain electrodes are provided on the substrate 610. Various things may be used as the substrate 610. As described above, it is preferable to use a transparent substrate to enable back exposure in a manufacturing process.

The pair of source and drain electrodes may be provided on the same plane. And an end portion of the source electrode 621, 622, and 623 in the drain electrode direction corresponding to the source electrode, and an end portion of the source electrode 621, 622, and 623 in the source electrode direction corresponding to the drain electrode of the drain electrode 631, 632, and 633. The first insulating layer 650 may be disposed to cover the source electrodes 621, 622, and 623 and the drain electrodes 631, 632, and 633. As described above, the first insulating layer 650 may be formed of a photoresist, particularly a positive photoresist. The method of forming the first insulating layer 650 having the above-described shape is the same as described above in the description of the organic thin film transistor according to the fifth embodiment.

Meanwhile, the source electrodes 621, which contact the source electrodes 621, 622, 623, and the drain electrodes 631, 632, and 633, which are not exactly covered with the first insulating layer 650, respectively. 622 and 623 and an organic semiconductor layer 660 in contact with exposed portions of the drain electrodes 631, 632, and 633. A second insulating film 670 is provided on the organic semiconductor layer 660 to cover the organic semiconductor layer 660. A pair of the source and drain electrodes is formed on the second insulating film 670. Gate electrodes 681, 682, and 683 are provided to correspond to 691, 692, and 693.

In the above structure, the organic semiconductor layer 660 is not patterned for each organic thin film transistor. However, as shown in FIG. 7, in each of the pairs 691, 692, and 693 of the source and drain electrodes, the length of the organic semiconductor layer between the source electrode and the drain electrode extends from the top surface of the substrate 610. While being formed very short along the length of the organic semiconductor layer between the pair of the source and drain electrodes (691, 692, 693) is formed very long along the upper surface of the first insulating layer 650, It is possible to prevent the occurrence of cross talk between the organic thin film transistors.

In addition, in the organic thin film transistor array according to the present exemplary embodiment having the above structure, the first insulating layer 650 may include the source electrodes 621, 622, and 623 and the drain electrodes 631, 632, and 633. The upper area of the gate electrode 681, 682, and 683 overlaps the source electrodes 621, 622, and 623 and the drain electrodes 631, 632, and 633. Parasitic capacitance may be reduced by the thickness of the first insulating layer 650. Therefore, the ends of the gate electrodes do not need to be exactly overlapped with the ends of the source electrodes and the ends of the drain electrodes, thereby facilitating the manufacturing process and improving the yield.

Meanwhile, the gate electrodes 681, 682, and 683 are patterned, which may be naturally patterned by forming the gate electrodes 681, 682, and 683 using an inkjet printing method. In addition, as described above in the description of the method of manufacturing the organic thin film transistor array, a gate electrode layer is formed on the entire surface of the substrate 610, and the gate electrode layer is patterned to form the gate electrodes 681, 682, and 683. ) May be formed. At this time, as in the organic thin film transistor array according to the seventh exemplary embodiment of the present invention illustrated in FIG. 8, the second insulating layers 771, 772, and 773 and the organic semiconductor layer 761 under the gate electrode layer are patterned. , 762, 763 may also be patterned at the same time. Through this, crosstalk between adjacent organic thin film transistors can be completely prevented. Of course, unlike that shown in FIG. 8, the first insulating film under the organic semiconductor layer may also be patterned at the same time.

In addition, as in the organic thin film transistor array according to the eighth preferred embodiment of the present invention illustrated in FIG. 9, the organic semiconductor layers 861, 862, and 863 each have a pair of source and drain electrodes 891, 892, and 893. It may be provided so as to correspond to.

10 is a schematic cross-sectional view of an organic thin film transistor array according to a ninth preferred embodiment of the present invention.

The organic thin film transistor array according to the present embodiment differs from the organic thin film transistor array according to the sixth embodiment described above by using isolation walls in the region between the pairs 991, 992, and 993 of the source electrode and the drain electrode. 940 is provided.

As described in more detail in the method of manufacturing an organic thin film transistor array to be described later, in order to manufacture the first insulating film 950 having a shape as described above in the description of the organic thin film transistor array according to the sixth embodiment described above, A photoresist is formed on the entire surface of the substrate 910, and the photoresist is irradiated with ultraviolet rays through the substrate 910.

Irradiating ultraviolet rays to the photoresist through the substrate 910 may include a surface on which source electrodes 921, 922, and 923 and drain electrodes 931, 932, and 933 of the substrate 910 are formed. This means that the opposite side of the UV irradiation. The ultraviolet rays reach the photoresist through the transparent substrate 910. In this case, since the ultraviolet light cannot penetrate the source electrodes 921, 922, and 923 and the drain electrodes 931, 932, and 933, the ultraviolet light is the source electrodes 921, 922, and 923. Only the photoresist in the area between the electrodes 931, 932, 933 is reached.

Therefore, when the positive photoresist is used, the photoresist of the regions between the source electrodes 921, 922, and 923 and the drain electrodes 931, 932, and 933 is weakened. Therefore, if this phenomenon is developed, only photoresists of regions between the source electrodes 921, 922, and 923 and the drain electrodes 931, 932, and 933 having weakened coupling are removed, thereby removing the respective source electrodes 921, 922,. The source electrodes 921 and 922 such that an end portion in the direction of the drain electrode corresponding to the source electrode of 923 and an end portion in the direction of the source electrode corresponding to the drain electrode of each of the drain electrodes 931, 932 and 933 are exposed. And a first insulating layer 950 covering the drain electrodes 931, 932, and 933.

At this time, the photoresist of the region where the source electrodes 921, 922, 923 and the drain electrodes 931, 932, and 933 that do not form the ultraviolet rays are all removed. In addition to the region between the electrodes 921, 922, 923 and the drain electrode corresponding to the source electrode, the photoresist of the region between the pair of the source electrode and the drain electrode 991, 992, 993 is also removed. Therefore, the isolation walls 940 formed of a material blocking ultraviolet rays are provided in an area between the pairs of the source electrode and the drain electrode 991, 992, and 993 so that the photoresist of the area is not removed. Can be. Any material that does not block UV light may be used as a material of the isolation wall 940, and in particular, a nitride film may be used.

On the other hand, since the research on the flexible display device has been actively conducted recently, since the organic thin film transistors and the organic thin film transistor arrays according to the above-described embodiments have flexible characteristics, such a flexible display device can be implemented using them. have. That is, in the case of a thin film transistor liquid crystal display device or an active driving type electroluminescent display device, a thin film transistor is provided for each subpixel to control the operation of each subpixel. By using the organic thin film transistors and the organic thin film transistor array, a flexible display device can be implemented. In addition, even if a thin film transistor is not provided for each subpixel, organic thin film transistors and organic thin film transistor arrays according to the above-described embodiments may be used. In addition, the present invention may be provided in any device including an organic thin film transistor such as an electronic sheet, a smart card, a product tag, or a plastic chip (RFID) for RFID. .

11 to 18 are cross-sectional views schematically illustrating a manufacturing process of an organic thin film transistor array according to an exemplary embodiment of the present invention.

First, as illustrated in FIG. 11, pairs 991, 992, and 993 of a plurality of source and drain electrodes are formed on the substrate 910. The isolation walls 940 are formed between the pairs 991, 992, and 993 of the source electrode and the drain electrode. Of course, alternatively, a plurality of isolation walls 940 are formed on the substrate 910, and then a pair of source electrodes and drain electrodes 991, 992, 993 in each space between the isolation walls 940. ) May be performed. In this case, the isolation walls 940 may be formed of a material that blocks ultraviolet rays, and in particular, a nitride film may be used.

After the above steps, the positive photoresist 950a is applied to cover the source electrodes 921, 922, and 923 and the drain electrodes 931, 932, and 933. In addition, the photoresist 950a is irradiated with ultraviolet rays through the substrate 910.

Irradiating ultraviolet light to the photoresist through the substrate 910, as shown in FIG. 13, source electrodes 921, 922, 923 and drain electrodes 931, 932 of the substrate 910. , 933) is irradiated with ultraviolet light on the opposite side to the surface on which it is formed. Therefore, the substrate 910 is preferably a transparent substrate so that ultraviolet light can pass through the substrate 910.

The irradiated ultraviolet rays reach the photoresist 950a through the transparent substrate 910. In this case, since the ultraviolet light cannot penetrate the source electrodes 921, 922, 923, the drain electrodes 931, 932, 933, and the isolation walls 940, the ultraviolet light does not penetrate the source electrode and the drain electrode. Only the photoresist in the region between the source and drain electrodes of the pairs 991, 992, and 993 of. Therefore, when the positive photoresist is used, the coupling of the photoresist in the region between the source electrode and the drain electrode of the pairs 991, 992, and 993 of the source electrode and the drain electrode is weakened.

After irradiating ultraviolet rays as described above, the photoresist is developed. Developing the photoresist removes only the photoresist in the region where the coupling is weakened as described above. As shown in FIG. 14, the photoresist corresponds to the source electrode of each of the source electrodes 921, 922, and 923. The source electrodes 921, 922, and 923 and the drain electrodes, in which an end in a direction of a drain electrode and an end in a direction of a source electrode corresponding to the drain electrode of each of the drain electrodes 931, 932, and 933 are exposed. A first insulating layer 950 is formed to cover 931, 932, 933.

An organic semiconductor layer is then formed in contact with the exposed end of each of the source electrodes 921, 922, 923 and the exposed end of the drain electrode corresponding to the source electrode, respectively. In this case, as shown in FIG. 15, the organic semiconductor layer is rotated by rotating the substrate 910 after dropping a material forming the organic semiconductor layer on the first insulating layer 950. A material to be formed may be spread over the entire surface of the substrate 910 so that the organic semiconductor layer 960 may be formed over the entire surface of the substrate 910. Of course, unlike FIG. 15, the material forming the organic semiconductor layer is dropped between the respective source electrodes 921, 922, and 923 and the drain electrode corresponding to the source electrode by an inkjet printing method, thereby preventing the respective sources. Of course, the organic semiconductor layer may be formed only in the region between the electrodes 921, 922, 923 and the drain electrode corresponding to the source electrode. Hereinafter, for convenience, only the case where the organic semiconductor layer 960 is formed on the entire surface of the substrate 910 will be described as illustrated in FIG. 15.

In this case, when the isolation walls 940 are not provided as described above, the photoresist of the region between the pairs 991, 992, and 993 of the source electrode and the drain electrode is also removed. In this case, when the organic semiconductor layer is formed by the spin coating method, as shown in FIG. 16, each source electrode 921, 922 is also formed in the region between the pair of the source electrode and the drain electrode 991, 992, and 993. 923 and an organic semiconductor layer having a length approximately equal to the distance between the drain electrode corresponding to the source electrode, which causes cross talk between adjacent organic thin film transistors. Therefore, by providing the isolation walls 940 as described above, it is possible to prevent such cross talk.

After forming the organic semiconductor layer 960 as described above, as shown in FIG. 17, forming a second insulating layer 970 to cover the organic semiconductor layer 960 and the second insulating layer ( An organic thin film transistor array is manufactured by forming gate electrodes 981, 982, and 983 on the upper portion of the 970 so as to correspond to the pairs 991, 992, and 993 of the source and drain electrodes.

In this case, forming the gate electrodes 981, 982, and 983 on the second insulating layer 970 to correspond to the pairs 991, 992, and 993 of the source and drain electrodes, respectively, using a mask. Through deposition, gate electrodes 981, 982, and 983 may be formed on the second insulating layer 970 to correspond to the pairs 991, 992, and 993 of the source and drain electrodes. Alternatively, a gate electrode layer may be formed to cover the second insulating layer 970 and the gate electrode layer may be patterned to correspond to the pairs 991, 992, and 993 of the source and drain electrodes, respectively. , 982, 983 may be formed. In the latter case, the organic semiconductor layer 960 is simultaneously patterned when the gate electrode layer is patterned, so that the gates correspond to the pairs 991, 992, and 993 of the source and drain electrodes, as shown in FIG. 18. Electrodes 981, 982, 983 and patterned organic semiconductor layer 960 may be formed. Of course, the gate electrodes may be formed using an inkjet printing method other than deposition.

As described above, the number of times of use of the mask can be reduced by irradiating ultraviolet rays using the source electrodes, the drain electrodes and the isolation walls, and the ends of the gate electrodes exactly match the ends of the source electrodes and the ends of the drain electrodes. It is possible to simplify the manufacturing process while facilitating the manufacturing method, and to improve the yield while reducing the manufacturing cost.

In the method of manufacturing the organic thin film transistor array, only the manufacturing method of the array as illustrated in FIGS. 17 and 18 has been described. However, the method of manufacturing an array in which a plurality of organic thin film transistors as illustrated in FIGS. Of course, it can also be applied.

According to the organic thin film transistor, the organic thin film transistor array, the flat panel display device including the organic thin film transistor or the organic thin film transistor array, and the manufacturing method of the organic thin film transistor array of the present invention made as described above, the following effects are obtained. You can get it.

First, an area in which the gate electrode overlaps the source electrode and the drain electrode by having a first insulating layer disposed on the source electrode and the drain electrode of the organic thin film transistor and having a gate electrode formed on the first insulating layer. Even if this is large, the parasitic capacitance can be reduced by the thickness of the first insulating film, so that the end of the gate electrode does not need to exactly overlap the end of the source electrode and the end of the drain electrode, thereby facilitating the manufacturing process and increasing the yield. Can be improved.

Secondly, in the organic thin film transistor array, the first insulating film is provided between the pair of source and drain electrodes, so that in the pair of the source and drain electrodes, the organic semiconductor layer between the source and drain electrodes is formed. While the length is made very short, the length of the organic semiconductor layer between each pair of the source and drain electrodes is made very long along the upper surface of the first insulating layer, so that the cross talk between the organic thin film transistors It can be prevented from occurring.

Third, the number of times of use of the mask can be reduced by patterning the photoresist by irradiating ultraviolet rays using the source electrodes, the drain electrodes and the isolation walls.

Although the present invention has been described with reference to the embodiments shown in the drawings, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (33)

Board; A source electrode and a drain electrode provided on the substrate; A first insulating film covering the source electrode and the drain electrode such that an end portion of the source electrode in the direction of the drain electrode and an end portion of the drain electrode in the direction of the source electrode are exposed; An organic semiconductor layer in contact with the source electrode and the drain electrode, respectively; A second insulating film covering the organic semiconductor layer; And And a gate electrode provided over the second insulating layer. The method of claim 1, The substrate is an organic thin film transistor, characterized in that the transparent substrate. The method of claim 1, And the first insulating film is a photoresist. The method of claim 1, And the organic semiconductor layer is provided to cover the first insulating layer. The method of claim 1, And the organic semiconductor layer is provided between an end portion of the source electrode in the direction of the drain electrode and an end portion of the drain electrode in the direction of the source electrode. The method of claim 5, And the second insulating layer is formed to cover the first insulating layer. The method of claim 1, The gate electrode is provided to cover the second insulating film. The method of claim 1, And the gate electrode is provided to correspond to a region between an end portion of the source electrode in the direction of the drain electrode and an end portion of the drain electrode in the direction of the source electrode. The method of claim 1, Separation walls provided on the same plane as the source electrode and the drain electrode are further provided in at least one of a direction opposite to the drain electrode direction of the source electrode and a direction opposite to the source electrode direction of the drain electrode. An organic thin film transistor. The method of claim 9, And the separator is formed of a material that blocks ultraviolet rays. The method of claim 9, And the separator is a nitride film. Board; Pairs of a plurality of source and drain electrodes provided on the substrate; A first insulating layer covering the source electrodes and the drain electrodes such that an end portion in a drain electrode direction corresponding to the source electrode of each source electrode and an end portion in a source electrode direction corresponding to the drain electrode of each drain electrode are exposed; ; An organic semiconductor layer in contact with the exposed ends of the source electrodes and the exposed ends of the drain electrodes; A second insulating film covering the organic semiconductor layer; And And gate electrodes disposed on the second insulating layer and corresponding to the pairs of the source and drain electrodes, respectively. The method of claim 12, And the substrate is a transparent substrate. The method of claim 12, And the first insulating layer is a photoresist. The method of claim 12, And an isolation wall between the pair of the source electrode and the drain electrode. The method of claim 15, And the isolation walls are formed of a material that blocks ultraviolet rays. The method of claim 15, And the isolation walls are nitride films. The method of claim 12, And the organic semiconductor layer is provided over the entire surface of the substrate. The method of claim 12, And the organic semiconductor layer is provided to correspond to each pair of the source and drain electrodes. A flat panel display device comprising the organic thin film transistor according to any one of claims 1 to 11. 20. A flat panel display device comprising the organic thin film transistor array of any one of claims 12 to 19. Forming a plurality of pairs of source and drain electrodes on top of the substrate; Applying a positive photoresist to cover the source electrodes and the drain electrodes; Irradiating ultraviolet rays to the photoresist through the substrate; Developing the photoresist to expose an end portion in a drain electrode direction corresponding to the source electrode of each source electrode and an end portion in a source electrode direction corresponding to the drain electrode of each drain electrode; Forming an organic semiconductor layer in contact with the exposed end of each source electrode and the exposed end of the drain electrode corresponding to the source electrode, respectively; Forming a second insulating film to cover the organic semiconductor layer; And And forming gate electrodes on the second insulating layer so as to correspond to each of the pair of source and drain electrodes. The method of claim 22, The substrate is a method of manufacturing an organic thin film transistor array, characterized in that the transparent substrate. The method of claim 22, Between forming a plurality of pairs of source and drain electrodes on top of the substrate, and applying a positive photoresist to cover the source and drain electrodes. Forming isolation walls between the pairs. The method of claim 22, Prior to forming a plurality of pairs of source and drain electrodes on top of the substrate, further comprising forming a plurality of isolation walls on the top of the substrate, a plurality of source and drain electrodes on the substrate Forming the pairs of, forming a pair of the source electrode and the drain electrode in each space between the isolation walls, the method of manufacturing an organic thin film transistor array. The method of claim 24 or 25, And the isolation walls are made of a material that blocks ultraviolet rays. The method of claim 24 or 25, And the isolation walls are nitride films. The method of claim 24 or 25, Forming an organic semiconductor layer in contact with the exposed end of each of the source electrode and the exposed end of the drain electrode corresponding to the source electrode, characterized in that the step of forming an organic semiconductor layer using a spin coating method A method of manufacturing an organic thin film transistor array. The method of claim 22, Forming an organic semiconductor layer in contact with the exposed end of each source electrode and the exposed end of the drain electrode corresponding to the source electrode, characterized in that the step of forming an organic semiconductor layer using an inkjet printing method A method of manufacturing an organic thin film transistor array. The method of claim 22, The forming of the gate electrodes to correspond to the pairs of the source and drain electrodes on the second insulating layer may include pairing the respective source and drain electrodes on the second insulating layer by deposition using a mask. Forming gate electrodes to correspond to the organic thin film transistor array. The method of claim 22, Forming gate electrodes on the second insulating layer to correspond to the pair of source and drain electrodes may include forming a gate electrode layer to cover the second insulating layer, and patterning the gate electrode layer to form the gate electrode layer. Forming gate electrodes so as to correspond to a pair of the source electrode and the drain electrode. The method of claim 31, wherein Forming an organic semiconductor layer in contact with the exposed end of each source electrode and the exposed end of the drain electrode corresponding to the source electrode, respectively, forming an organic semiconductor layer using a spin coating method, the gate Patterning an electrode layer to form gate electrodes to correspond to the pairs of the source and drain electrodes may include simultaneously patterning the gate electrode layer and the organic semiconductor layer to correspond to the pairs of the source and drain electrodes. Forming electrodes and a patterned organic semiconductor layer. The method of claim 22, Forming gate electrodes on the second insulating layer so as to correspond to the pair of source and drain electrodes may include forming gate electrodes by using an inkjet printing method. Way.

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