JP3748158B2 - Liquid crystal display device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an active matrix type liquid crystal display device and a method of manufacturing the same, and more particularly to a structure of a pad portion for inputting a signal to a gate line of the liquid crystal display device.
[0002]
[Prior art]
  In recent years, OA (Office Automation) devices such as personal computers have become portable, and the cost reduction of display devices has become an important issue. This display device has a configuration in which a pair of substrates each having an electrode formed therebetween with a display medium having electro-optic characteristics is provided, and display is performed by applying a voltage between the electrodes.
[0003]
  As such a display medium, liquid crystal, electroluminescence, plasma, electrochromic, and the like are generally used. In particular, a liquid crystal display device (LCD: Liquid Crystal Display) using liquid crystal can display with low power consumption. Therefore, practical application is most advanced.
[0004]
  As for the display mode and driving method of such a liquid crystal display device, a simple matrix system such as a super twisted nematic (STN) belongs to a class that can achieve the lowest cost, but in the future, information As the use of media progresses, higher resolution and higher contrast of displays, multi-gradation such as multi-color and full-color, and wide viewing angle are required, making it difficult to deal with the simple matrix method. It is considered to be.
[0005]
  Therefore, an active matrix type liquid crystal display device has been proposed in which switching elements (active elements) are provided in each pixel to increase the number of scan electrodes that can be driven. Contrast, multi-gradation, wide viewing angle, etc. are being achieved. In this active matrix type liquid crystal display device, pixel electrodes provided in a matrix and scanning lines passing through the vicinity of the pixel electrodes are electrically connected via active elements.
[0006]
  As such an active element, there is a two-terminal nonlinear element (MIM: Metal Insulator Metal) or a three-terminal nonlinear element, and the most widely used active element is a thin film transistor which is a three-terminal nonlinear element. (TFT: Thin Film Transistor).
[0007]
  Development of a thin film transistor (hereinafter referred to as TFT) used as a switching element for driving a liquid crystal in an active matrix liquid crystal display device as described above is being actively performed. Up to now, anodizing the gate electrode material of TFT has good insulation, high reliability and high withstand voltage, low interface state density with semiconductor, and large electric field effect on semiconductor, etc. It is known that TFTs having characteristics and extremely good characteristics can be produced.
[0008]
  A process for forming a liquid crystal display device using such a TFT will be described with reference to FIGS. FIG. 4 is a plan view showing a display portion and a pad region on a glass substrate. FIGS. 5A to 5D are views showing a TFT portion, a gate wiring portion, and a manufacturing process of a conventional liquid crystal display device. It is sectional drawing with a pad area | region.
[0009]
  As shown in FIG. 4, a general liquid crystal display device includes a display unit and a pad region formed on a glass substrate 500, and a plurality of gate pads 508 and source pads 515 are formed in the pad region. . Among these, the gate bus line 502 extends from the gate pad 508, and the source bus line 516 extends from the source pad 515. Further, a TFT 517 is formed near the intersection of the gate bus line 502 and the source bus line 516, and pixel electrodes (not shown) are formed in a matrix corresponding to the TFT 517.
[0010]
  First, as shown in FIG. 5A, a manufacturing method of such a liquid crystal display device uses a material that can be anodized such as Al on a glass substrate 500 to form a gate electrode 501, a gate bus line 502, and A gate pad body 508 is formed by patterning. Al used here has a low resistance and is a material suitable for use as a wiring.
[0011]
  Next, the gate pad body 508 is covered with a resist pattern, anodization is performed on the gate electrode 501 and the gate bus line 502 which are regions other than the gate pad 508, and an anodic oxide film 503 is formed on the gate electrode 501 and the gate bus line 502. Form. At this time, the anodic oxide film 503 is not formed on the gate pad body 508.
[0012]
  Subsequently, an insulating film to be the gate insulating film 504 is formed on the entire surface of the glass substrate 500 using SiNx.
[0013]
  Next, as shown in FIG. 5B, the gate insulating film 504 located in the pad region is etched to form an opening 505 on the gate pad main body 508. The TFT portion is formed by patterning a semiconductor material to be the active layer 520 using p-Si, a-Si, or the like, and then a source bus line 516 using a metal material such as Al or Cr. A source electrode 506 and a drain electrode 507 are formed. At this time, although not shown in FIG. 5, the source pad 515 is simultaneously formed in the source pad region. Further, after such a TFT substrate is completed, an anisotropic conductive sheet is interposed between the opening 505 provided on the gate pad main body 508, and a flexible substrate and a gate which are external signal input means are provided. Connection to the pad body 508 is performed.
[0014]
  Thereafter, as shown in FIG. 5C, the pixel electrode 514 is formed using a transparent conductive film such as ITO connected to the drain electrode 507 described above. At this time, it is a signal input means from the outside. In order to stabilize the connection between the flexible substrate and the gate pad main body 508, a gate pad protective film 509 made of a transparent conductive film may be formed also on the gate pad main body 508. In particular, when the gate electrode 501, the gate bus line 502, and the gate pad body 508 are made of Al, since Al is not a hard material, it is not suitable as a pad material. It is preferable to form a gate pad protective film 509 using a film.
[0015]
  In the TFT substrate thus formed, the gate pad 510 is constituted by the gate pad main body 508 and the gate pad protective film 509.
[0016]
  Further, as shown in FIG. 5D, an interlayer insulating film 511 having a film thickness of 2 μm or more is formed on the entire surface of the substrate 500 including the source electrode 506 and the drain electrode 507 by using, for example, an organic material. An opening 512 may be provided in the film 511, and the pixel electrode 514 may be formed over the opening 512. In this case, the interlayer insulating film 511 on the gate pad main body 508 is removed to provide an opening 513 to expose a connection portion with a flexible substrate which is an external signal input means, and this exposed gate pad. A protective film 509 is formed in the opening 513 including on the main body 508.
[0017]
  Such a structure is called a pixel-on-passive structure, and the pixel electrode 514 can be formed on the source bus line 516 so as to greatly improve the aperture ratio of the liquid crystal display device. And a bright display can be realized.
[0018]
[Problems to be solved by the invention]
  However, the gate pad having the above-described structure has a problem that a connection failure occurs when it is connected to a flexible substrate as a signal input means from the outside due to a step such as an opening formed on the insulating film. Had.
[0019]
  Further, when the pixel electrode is formed of a transparent conductive film such as ITO, there is a problem that the gate pad is damaged by the etchant when the transparent conductive film is etched.
[0020]
  Even if this is a case where a pad protection part made of a transparent conductive film is formed on the top of the gate pad, the gate pad body is damaged by the infiltration of the etchant from the step of the opening provided in the gate pad part. There also arises a problem that a signal input to the gate pad portion cannot be transmitted to the gate bus line.
[0021]
  The present invention has been made in view of the above-described conventional problems, and is a liquid crystal display device in which a gate pad portion formed on a substrate and a flexible substrate which is a signal input means from the outside are well connected And it aims at providing the manufacturing method.
[0022]
[Means for Solving the Problems]
  In order to achieve the above object, a liquid crystal display device according to claim 1 of the present invention includes a plurality of gate bus lines, a plurality of source bus lines, and the gate bus lines and source bus lines on at least a substrate. In a liquid crystal display device having a switching element formed in the vicinity of an intersection with a pixel electrode and a pixel electrode connected to the switching element, an external signal is applied to the gate bus line at the end of the gate bus line. A gate pad portion to which signal input means for supply is connected is provided, and the gate pad portion has a flat connection surface with the signal input means.In addition, a connection surface with the signal input means in the gate pad portion is formed on a flat surface made of an organic material formed on the entire surface of the substrate including the switching element, and the switching element has a source An electrode and a drain electrode, and the gate pad portion includes a gate pad main body portion formed of the same material as the source electrode and a gate pad protection portion formed of the same material as the pixel electrode, A barrier metal is interposed between the gate pad body portion and the gate pad protection portion, and the barrier metal extends to the gate pad region, thereby forming the gate pad region with the gate pad protection. A two-layer structure of the part and the barrier metalIt is characterized by that.
[0023]
  At this time, a part of the gate pad portion is preferably formed of the same material as the pixel electrode..
[0024]
  MaAt this time, the gate pad main body is preferably made of Al, and the gate pad protector is preferably made of ITO..
[0025]
  UpTo achieve the stated purpose, the present inventionPertaining toThe manufacturing method of the liquid crystal display device is as follows:At least a plurality of gate bus lines, a plurality of source bus lines, a switching element formed in the vicinity of an intersection of the gate bus lines and the source bus lines on the substrate, and the switching elements In a liquid crystal display device having a pixel electrode connected to a child, a gate pad portion to which signal input means for supplying an external signal to the gate bus line is connected to an end portion of the gate bus line. The gate pad portion has a flat connection surface with the signal input means, and the connection surface with the signal input means in the gate pad portion is on a substrate including the switching element. It is formed on a flat surface made of an organic material formed on the entire surface ofIn the method for manufacturing a liquid crystal display device, a step of forming a gate electrode and a gate bus line on the substrate, anodizing the gate electrode and the gate bus line, and an anodic oxide film on the gate electrode and the gate bus line Forming a gate insulating film on the substrate including the gate electrode and the gate bus line, and forming an opening in the gate insulating film formed on an end of the gate bus line Forming a source electrode and a drain electrode on the gate electrode, and forming a gate pad body by covering the opening formed on the end portion of the gate bus line with the same material as the source electrode. And an interlayer insulating film is formed on the substrate including the source electrode, the drain electrode, and the gate pad body by spin coating. A step of forming an opening in the interlayer insulating film formed on the drain electrode and on an end of the gate bus line; and covering the opening formed on the drain electrode, A gate pad protective film which is formed on the interlayer insulating film and covers the opening formed on the end portion of the gate bus line with the same material as the pixel electrode and is connected to the signal input means. And a step of forming over the insulating film.
[0026]
  According to the liquid crystal display device of the present invention, the gate pad portion of the liquid crystal display device and the flexible substrate as the signal input means from the outside are formed by forming a flat connection surface with the signal input means in the gate pad portion. It is possible to easily prevent a connection failure at the time of connection.
[0027]
  In addition, since the connection surface with the signal input means in the gate pad portion is formed on a flat surface made of an organic material formed on the substrate, the gate pad can be easily flat with the signal input means. The part can be formed.
[0028]
  Further, the gate pad portion is composed of a gate pad main body portion formed of the same material as the source electrode and a gate pad protection portion formed of the same material as the pixel electrode, thereby increasing the number of manufacturing steps. In addition, a liquid crystal display device having a highly reliable gate pad portion can be realized.
[0029]
  Further, it is preferable to dispose a metal such as TIW, Mo, TiN or the like as a barrier metal between the gate pad body portion made of Al and the pad protection portion made of ITO, and the barrier metal at this time extends to the pad region. By being formed, the pad region can have a two-layer structure of the pad protection part and the barrier metal, so that the reliability of the gate pad can be further improved.
[0030]
  According to the method for manufacturing a liquid crystal display device of the present invention, a step of forming a gate electrode and a gate bus line on a substrate, an anodizing process on the gate electrode and the gate bus line, and an anode on the gate electrode and the gate bus line Forming an oxide film; forming a gate insulating film on a substrate including a gate electrode and a gate bus line; and forming an opening in the gate insulating film formed on an end of the gate bus line. And forming a gate pad body over the opening formed on the end of the gate bus line with the same material as the source electrode, and forming a source electrode and a drain electrode on the gate electrode. This eliminates the need to cover the gate pad portion with an anodizing-preventing resist during anodic oxidation, and facilitates the gate pad having a flat connection surface. It is possible to form a de section, it is possible to realize a highly reliable liquid crystal display device.
[0031]
  Also, an interlayer insulating film is formed on the substrate including the source electrode, the drain electrode, and the gate pad body, and an opening is formed in the interlayer insulating film formed on the drain electrode and the end of the gate bus line. Covering the opening formed on the drain electrode, forming the pixel electrode on the interlayer insulating film, and covering the opening formed on the end of the gate bus line with the same material as the pixel electrode. A step of forming a gate pad protective film on the interlayer insulating film, whereby a gate pad portion having a flat connection surface can be easily formed, and has high reliability and high aperture ratio. A liquid crystal display device can be realized.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3.
[0033]
  1A to 1C are cross-sectional views of a TFT region, a gate wiring portion, and a pad region showing a manufacturing process of the liquid crystal display device (first liquid crystal display device) in the present embodiment. The layout on the substrate of the first liquid crystal display device is the same as the conventional plan view shown in FIG.
[0034]
  First, as shown in FIG. 1A, the first liquid crystal display device uses a material capable of anodic oxidation such as Al and Ta for the TFT region and the gate wiring portion on the glass substrate 100 to form the gate electrode 101. The gate bus line 102 was patterned to a thickness of 300 nm.
[0035]
  Then, anodization was performed on the gate electrode 101 and the gate bus line 102, and an anodic oxide film 103 having a thickness of 10 nm was formed on the upper and side portions of the gate electrode 101 and the gate bus line 102.
[0036]
  Thereafter, an insulating film to be the gate insulating film 104 was formed on the entire surface of the glass substrate 100 with a thickness of 300 nm using SiNx.
[0037]
  Next, as shown in FIG. 1B, in the TFT region, a semiconductor material to be the active layer 120 is patterned using p-Si, a-Si, or the like to form a thickness of 50 nm to 300 nm. .
[0038]
  Subsequently, after an opening 105 is formed on the gate bus line 102 at the end of the gate wiring portion using a dry etching method, a source material 106 and a drain electrode of the TFT are formed using a metal material such as Al or Cr. And 107 respectively. At the same time, the opening 105 formed on the gate bus line 102 at the end of the gate wiring portion is covered, and the gate pad body is formed to a thickness of 300 nm with the same material as the source electrode 106 and the drain electrode 107 described above. 108 was formed.
[0039]
  At this time, although not shown, source pads were simultaneously formed on the source bus lines and the end portions of the source bus lines.
[0040]
  In the first liquid crystal display device, as described above, the opening 105 is formed on the gate bus line 102 at the end of the gate wiring portion by etching, whereby the gate bus line 102 and the gate pad main body 108 are separated. Since the connection is made, it is not necessary to provide a resist for anodizing prevention in the pad region, the manufacturing process can be shortened, and the manufacturing yield can be prevented from being lowered due to substrate contamination due to the resist formation. It becomes.
[0041]
  Thereafter, as shown in FIG. 1C, the pixel electrode 114 is formed using a transparent conductive film such as ITO connected to the drain electrode 107 described above. At this time, it is a signal input means from the outside. In order to stabilize the connection between the flexible substrate and the gate pad body 108, a gate pad protective film 109 made of a transparent conductive film may be formed on the gate pad body 108. In particular, when the gate electrode 101, the gate bus line 102, and the gate pad main body 108 are made of Al, since Al is not a hard material, it is not suitable as a pad material. It is preferable to form the gate pad protective film 109 using a film.
[0042]
  In the TFT substrate thus formed, the gate pad 110 is constituted by the gate pad main body 108 and the gate pad protective film 109.
[0043]
  In such a first liquid crystal display device, since the opening is not formed in the pad region where the connection with the flexible substrate as the signal input means from the outside is made, the connection surface with the flexible substrate becomes flat. Thus, connection failure in the pad region is unlikely to occur. Further, since the gate pad main body is formed of the same material as the source electrode and the drain electrode, the gate pad as described above can be easily formed.
[0044]
  2A to 2C are cross-sectional views of a TFT region, a gate wiring portion, and a pad region, showing a manufacturing process of a liquid crystal display device (second liquid crystal display device) according to another embodiment. FIG. 3 is a cross-sectional view showing the second liquid crystal display device. The layout on the substrate of the second liquid crystal display device is also the same as the conventional plan view shown in FIG.
[0045]
  In the second liquid crystal display device, as shown in FIG. 2A, first, a gate electrode 101 is used by using an anodic oxidation material such as Al and Ta for the TFT region and the gate wiring portion on the glass substrate 100. The gate bus line 102 was patterned to a thickness of 300 nm.
[0046]
  Then, anodization was performed on the gate electrode 101 and the gate bus line 102, and an anodic oxide film 103 having a thickness of 10 nm was formed on the upper and side portions of the gate electrode 101 and the gate bus line 102.
[0047]
  Thereafter, an insulating film to be the gate insulating film 104 was formed on the entire surface of the glass substrate 100 with a thickness of 300 nm using SiNx.
[0048]
  Next, in the TFT region, a semiconductor material to be the active layer 120 was patterned using p-Si, a-Si, or the like to form a thickness of 50 nm to 300 nm.
[0049]
  Subsequently, after an opening 105 is formed on the gate bus line 102 at the end of the gate wiring portion using a dry etching method, a source material 106 and a drain electrode of the TFT are formed using a metal material such as Al or Cr. And 107 respectively. At the same time, the opening 105 formed on the gate bus line 102 at the end of the gate wiring portion is covered, and the gate pad body is formed to a thickness of 300 nm with the same material as the source electrode 106 and the drain electrode 107 described above. 108 was formed.
[0050]
  At this time, although not shown, source pads were simultaneously formed on the source bus lines and the end portions of the source bus lines.
[0051]
  Up to this point, the process is exactly the same as that of the first liquid crystal display device. In the second liquid crystal display device, as described above, the opening 105 is formed on the gate bus line 102 at the end of the gate wiring portion by etching. Thus, since the gate bus line 102 and the gate pad main body 108 are connected, it is not necessary to provide a resist for anodization prevention in the pad region, and the manufacturing process can be shortened. It is also possible to prevent a decrease in manufacturing yield due to substrate contamination accompanying resist formation.
[0052]
  Thereafter, as shown in FIG. 2B, an interlayer insulating film 111 is formed on the entire surface of the substrate 100 including the source electrode 106 and the drain electrode 107 formed as described above using an organic material such as acrylic resin. It was formed with a thickness of 2 μm or more by spin coating.
[0053]
  As described above, since the interlayer insulating film 111 is formed using the spin coating method, a flat surface can be easily formed on the substrate 100. Further, since the interlayer dielectric film 111 is formed of an organic material as described above, the relative permittivity of the organic material is usually as small as 3.5 or less, so that the liquid crystal layer is affected from below the interlayer dielectric film 111. It is possible to reduce it.
[0054]
  Thereafter, as shown in FIG. 2C, openings 112 and 113 are formed in the interlayer insulating film 111 located on the drain electrode 107 in the TFT region and on the gate bus line 102 at the end of the gate wiring portion, The pixel electrode 114 and the pad protection part 115 were formed on the interlayer insulating film 111 with a transparent conductive film such as ITO so as to cover the openings 112 and 113.
[0055]
  In the case of such a configuration, the connection between the liquid crystal display device and the flexible substrate which is a signal input unit from the outside is performed by the pad protection unit 115.
[0056]
  Further, with such a structure, the pixel electrode 114 can be formed over the source bus wiring, and thus the aperture ratio of the liquid crystal display device can be improved.
[0057]
  At this time, when the material of the source electrode 106 and the drain electrode 107 described above is Al, an ohmic contact cannot be made with ITO, which is the material of the pixel electrode 114. Therefore, as shown in FIG. An opening 112 formed between the drain electrode 107 made of ITO and the pixel electrode 114 made of ITO, and an opening 113 formed between the gate pad body 108 made of Al and the pad protection portion 115 made of ITO. It is preferable to cover and arrange a metal such as TIW, Mo, TiN as the barrier metals 116 and 117.
[0058]
  By forming the barrier metal 117 at this time so as to extend to the pad region, the pad region can have a two-layer structure of the pad protection part 115 and the barrier metal 117. Reliability can be further improved.
[0059]
  In such a second liquid crystal display device, since the connection surface with the flexible substrate which is a signal input means from the outside is flat, a connection failure in the pad region is unlikely to occur. In addition, since the gate pad body is made of the same material as the source and drain electrodes, the gate pad can be easily formed.
[0060]
【The invention's effect】
  As described above, according to the liquid crystal display device of the present invention, the gate pad portion of the liquid crystal display device, the flexible substrate, etc. It is possible to easily prevent a connection failure at the time of connection with the signal input means.
[0061]
  In addition, since the connection surface with the signal input means in the gate pad portion is formed on a flat surface made of an organic material formed on the substrate, the gate pad can be easily flat with the signal input means. The part can be formed.
[0062]
  Further, it is preferable to dispose a metal such as TIW, Mo, TiN or the like as a barrier metal between the gate pad body portion made of Al and the pad protection portion made of ITO, and the barrier metal at this time extends to the pad region. By being formed, the pad region can have a two-layer structure of the pad protection part and the barrier metal, so that the reliability of the gate pad can be further improved.
[0063]
  Further, the gate pad portion is composed of a gate pad main body portion formed of the same material as the source electrode and a gate pad protection portion formed of the same material as the pixel electrode, so that the manufacturing process is not increased. In addition, a liquid crystal display device having a highly reliable gate pad portion can be realized.
[0064]
  In addition, according to the method for manufacturing a liquid crystal display device of the present invention, a gate pad portion having a flat connection surface can be easily formed, so that a highly reliable liquid crystal display device with a high aperture ratio can be realized. It is possible.
[Brief description of the drawings]
FIGS. 1A to 1C are cross-sectional views of a TFT region, a gate wiring portion, and a pad region showing a manufacturing process of a liquid crystal display device according to an embodiment of the present invention.
FIGS. 2A to 2C are cross-sectional views of a TFT region, a gate wiring portion, and a pad region showing a manufacturing process of a liquid crystal display device according to another embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a configuration of a liquid crystal display device according to another embodiment of the present invention.
FIG. 4 is a plan view showing a display portion and a pad region on a glass substrate in a liquid crystal display device.
FIGS. 5A to 5D are cross-sectional views of a TFT portion, a gate wiring portion, and a pad region showing a manufacturing process of a conventional liquid crystal display device.
[Explanation of symbols]
100 substrates
101 Gate electrode
102 Gate bus line
103 Anodized film
104 Gate insulation film
105 opening
106 Source electrode
107 Drain electrode
108 Gate pad body
109 Gate pad protector
110 Gate pad
111 Interlayer insulation film
112 opening
113 opening
114 pixel electrode
115 Pad protector
116 barrier metal
117 barrier metal
120 active layer
500 substrates
501 Gate electrode
502 Gate bus line
503 Anodized film
504 Gate insulation film
505 opening
506 Source electrode
507 Drain electrode
508 Gate pad body
509 Gate pad protector
510 Gate pad
511 Interlayer insulation film
512 opening
513 opening
514 Pixel electrode
515 Source Pad
516 Source bus line
517 TFT
520 active layer

Claims (4)

A plurality of gate bus lines; a plurality of source bus lines; a switching element formed in the vicinity of an intersection of the gate bus lines and the source bus lines; and a pixel electrode connected to the switching elements; In a liquid crystal display device having
A gate pad portion to which signal input means for supplying an external signal to the gate bus line is connected to the end portion of the gate bus line, and the gate pad portion is connected to the signal input portion. The connecting surface with the means is formed flat ,
The connection surface with the signal input means in the gate pad portion is formed on a flat surface made of an organic material formed on the entire surface on the substrate including the switching element, and
The switching element includes a source electrode and a drain electrode, and the gate pad portion includes a gate pad body portion formed of the same material as the source electrode, and a gate pad formed of the same material as the pixel electrode. Consisting of a protection part,
A barrier metal is interposed between the gate pad body portion and the gate pad protection portion, and the barrier metal extends to the gate pad region, thereby forming the gate pad region with the gate pad protection. the liquid crystal display device, characterized in that a two-layer structure parts and the barrier metal.   The liquid crystal display device according to claim 1, wherein a part of the gate pad portion is formed of the same material as the pixel electrode. 3. The liquid crystal display device according to claim 1, wherein the gate pad main body portion is made of Al, and the gate pad protection portion is made of ITO. A plurality of gate bus lines; a plurality of source bus lines; a switching element formed in the vicinity of an intersection of the gate bus lines and the source bus lines; and a pixel electrode connected to the switching elements; In a liquid crystal display device having
A gate pad portion to which signal input means for supplying an external signal to the gate bus line is connected to the end portion of the gate bus line, and the gate pad portion is connected to the signal input portion. The connecting surface with the means is formed flat,
In the method of manufacturing a liquid crystal display device, the connection surface of the gate pad portion with the signal input means is formed on a flat surface made of an organic material formed on the entire surface of the substrate including the switching element.
Forming a gate electrode and a gate bus line on the substrate;
Anodizing the gate electrode and the gate bus line, and forming an anodized film on the gate electrode and the gate bus line;
Forming a gate insulating film on the substrate including the gate electrode and the gate bus line;
Forming an opening in the gate insulating film formed on an end of the gate bus line;
Forming a source electrode and a drain electrode on the gate electrode, and forming a gate pad body by covering the opening formed on the end of the gate bus line with the same material as the source electrode;
Forming an interlayer insulating film on the substrate including the source electrode, the drain electrode, and the gate pad body by spin coating;
Forming an opening in the interlayer insulating film formed on the drain electrode and on the end of the gate bus line;
Covering the opening formed on the drain electrode, as well as the shape formed the pixel electrode on the interlayer insulating film, the pixel electrode of the same material, the opening formed on the end portion of the gate bus line And a step of forming a gate pad protective film for covering with the signal input means on the interlayer insulating film.

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