JP3873164B2 - Manufacturing method of active matrix type liquid crystal display panel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing an active matrix liquid crystal display panel.
[0002]
[Prior art]
When manufacturing an active matrix type liquid crystal display panel, in order to improve productivity, a glass substrate serving as a base of the liquid crystal display panel is prepared with a size corresponding to a plurality of liquid crystal display panels. A plurality of parts may be manufactured in batches until the process, and then divided into individual units.
[0003]
FIG. 2 is a view for explaining such a conventional example, and shows an equivalent circuit plan view in a state where pixel electrodes and the like are formed on a glass substrate having a size corresponding to a plurality of liquid crystal display panels. Is. The glass substrate 1 having a size corresponding to a plurality of liquid crystal display panels is finally cut along a cut line 2 indicated by an alternate long and short dash line, thereby being divided into individual pieces. In this case, the area surrounded by the cut line 2 is a panel forming area 3, and the periphery thereof is a non-panel forming area 4. In addition, a region surrounded by a two-dot chain line in the panel forming region 3 is a display region 5, and the periphery thereof is a non-display region 6.
[0004]
The display area 5 includes a plurality of pixel electrodes 7 arranged in a matrix, a thin film transistor 8 serving as a switching element connected to each of the pixel electrodes 7, and a scanning signal that is extended in the row direction to the thin film transistor 8. A plurality of scanning signal lines 9 for supplying and a plurality of data signal lines 10 extending in the column direction for supplying a data signal to the thin film transistor 8 are provided. The non-panel forming region 4 is provided with an antistatic ring 11 in a lattice shape.
[0005]
The left end portion of the scanning signal line 9 is connected to the output side connection pad 13 provided in the semiconductor chip mounting area 12 indicated by the dotted line of the non-display area 6. The output side connection pad 13 is connected to the antistatic ring 11 through a lead wire 14. The upper end portion of the data signal line 10 is connected to an output-side connection pad 16 provided in a semiconductor chip mounting area 15 indicated by a dotted line in the non-display area 6. The output side connection pad 16 is connected to the antistatic ring 11 through a lead wire 17. The input-side connection pads 18 and 19 provided in the semiconductor chip mounting areas 12 and 15 are connected to external connection terminals 20 provided at predetermined locations in the non-display area 6 through lead wires 21. The external connection terminal 20 is connected to the antistatic ring 11 through a lead wire 22.
[0006]
Next, a specific structure of a part of the liquid crystal display panel will be described with reference to FIG. A gate electrode G of a thin film transistor 8 made of Al metal such as Al (aluminum) or Al alloy is formed on the upper surface of the glass substrate 1. In this case, the scanning signal line 9, the output side connection pad 13, the routing line 14, and the antistatic ring 11 shown in FIG. 2 are formed simultaneously with the formation of the gate electrode G using the same material as the gate electrode G.
[0007]
A gate insulating film 31 made of silicon nitride is formed on the entire upper surface of the glass substrate 1 including the gate electrode G and the like. A semiconductor thin film 32 made of intrinsic amorphous silicon is formed at a portion corresponding to the gate electrode G at a predetermined position on the upper surface of the gate insulating film 31. A channel protective film 33 made of silicon nitride is formed at the center of the upper surface of the semiconductor thin film 32. Ohmic contact layers 34 and 35 made of n-type amorphous silicon are formed on both sides of the upper surface of the channel protective film 33 and on the upper surface of the semiconductor thin film 32 on both sides thereof. A drain electrode D and a source electrode S made of Cr (chromium) are formed on the upper surfaces of the ohmic contact layers 34 and 35.
[0008]
Data signal lines 10 made of Al-based metal are formed at predetermined locations on the upper surface of the drain electrode D and the upper surface of the gate insulating film 31. In this case, the output side connection pad 16, the routing line 17, the input side connection pads 18 and 19, the routing line 21, the external connection terminal 20, and the routing line 22 shown in FIG. It is formed simultaneously with the formation of the line 10. In addition, one end of each of the lead wires 17 and 22 is connected to the antistatic ring 11 through a contact hole (not shown) formed in the gate insulating film 31.
[0009]
An overcoat film (insulating film) 36 made of silicon nitride is formed on the entire upper surface of the gate insulating film 31 including the data signal lines 10 and the like. A pixel electrode 7 made of ITO (indium-tin oxide) is connected to the source electrode S through a contact hole 37 formed at a predetermined position of the overcoat film 36 at a predetermined position on the upper surface of the overcoat film 36. Is formed. 2 are exposed through openings (not shown) formed in the overcoat film 36. The output connection pads 13 and 16, the input connection pads 18 and 19, and the external connection terminals 20 shown in FIG. . In the liquid crystal display panel having the cross-sectional structure as described above, the ITO that constitutes the pixel electrode 7 is located on the top side of the thin film transistor 8 and may be referred to as a TOP-ITO structure.
[0010]
Here, the role of the antistatic ring 11 will be described. In the state before cutting along the cut line 2, for example, when static electricity is generated when the alignment film is rubbed, all the wirings in the panel forming region 3 are connected to the antistatic ring 11 in the non-panel forming region 4. Since the antistatic ring 11 is grounded, the generated static electricity can be quickly removed. Then, when cutting along the cut line 2, the lead lines 14, 17, and 22 are cut, and all the wirings in the panel forming region 3 are separated from the antistatic ring 11.
[0011]
[Problems to be solved by the invention]
By the way, in such a conventional liquid crystal display panel, the overcoat film 36 made of silicon nitride is formed by plasma CVD, but the film formation conditions in the plasma CVD apparatus are different between the central portion and the peripheral portion. Therefore, a defective portion such as a pinhole may occur in the overcoat film 36 formed in the non-panel forming region 4 located on the peripheral side. In such a case, when the ITO etching solution for forming the pixel electrode 7 penetrates into the defective portion of the overcoat film 36 and comes into contact with the lead lines 17 and 22 made of Al-based metal, the Al-ITO battery reaction occurs. As a result, the lead wires 17 and 22, the output side connection pads 13 and 16, the input side connection pads 18 and 19, the external connection terminal 20 and the like may be melted and disconnected or eroded, resulting in a failure.
An object of the present invention is to prevent disconnection of wiring and terminal portions even if there is a defect in an insulating film such as an overcoat film in a non-panel formation region.
[0012]
[Means for Solving the Problems]
According to the first aspect of the present invention, an insulating film is provided on a substrate having a panel forming region and a surrounding non-panel forming region, and an Al-based metal is provided under the insulating film in the panel forming region and the non-panel forming region. When manufacturing an active matrix type liquid crystal display panel in which a pixel electrode made of ITO is provided on the insulating film in the panel formation region, an ITO film is formed on the insulating film. Each of the plurality of connection pads made of an Al-based metal is formed through wet etching of the film to form the pixel electrode on the insulating film in the panel formation region and exposed through the opening formed in the insulating film. top and the ITO film is the remaining islands on the insulating film in the vicinity and forming an upper connection pad, the non-panel shaped Forming a protective film made of the ITO film on the entire said insulating film in the region is then that the was to remove by cutting the portion corresponding to the non-panel-forming region. According to the first aspect of the present invention, since the protective film made of the ITO film is formed on the entire insulating film in the non-panel forming region, even if there is a defect in the insulating film in the non-panel forming region. Thus, it is possible to prevent disconnection of the wiring under the defective portion. In this case, even if a protective film made of an ITO film is formed over the entire insulating film in the non-panel forming region, there is no problem because the portion corresponding to the non-panel forming region is subsequently cut and removed. According to a third aspect of the present invention, in the second aspect of the present invention, the connection pad is connected to a data signal line. According to a fourth aspect of the present invention, in the second aspect of the present invention, the connection pad is connected to a scanning signal line.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, a method for manufacturing an active matrix liquid crystal display panel according to an embodiment of the present invention will be described with reference to FIG. In this figure, the same parts as those in FIGS. 2 and 3 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. In the case of manufacturing a liquid crystal display panel in this embodiment, before forming the ITO film for forming the pixel electrode 7, that is, after forming the overcoat film 36 by plasma CVD, the source electrode S of the thin film transistor 8 is formed. A contact hole 37 is formed in the overcoat film 36 in the corresponding part. Simultaneously with the formation of the contact hole 37, the contact hole 41 is formed in the overcoat film 36 and the gate insulating film 31 in the portion corresponding to the output side connection pad 13 connected to one end of the scanning signal line, and the data A contact hole 42 is formed in the overcoat film 36 in a portion corresponding to the output side connection pad 16 connected to one end of the signal line.
[0014]
Next, an ITO film is formed on the entire top surface. Next, a photoresist (not shown) is deposited on the deposited ITO film, exposed using a predetermined mask, developed with an etching solution of the photoresist, and only on the ITO film to be patterned. The photoresist remains. Then, using the remaining photoresist as a mask, the ITO film formed on the overcoat film 36 is etched using an ITO etching solution and patterned into a shape as shown in FIG. By this patterning, the pixel electrode 7 connected to the source electrode S through the contact hole 37 is formed. Simultaneously with the formation of the pixel electrode 7, a protective film that covers the entire upper surface of the overcoat film 36 in the non-panel formation region 4. 43, and upper connection pads 44 and 45 are formed on the upper surfaces of the external connection pads 13 and 16 in the contact holes 41 and 42 and on the upper surface of the overcoat film 36 in the periphery thereof.
[0015]
In the above method, when developing the photoresist, since the entire surface of the overcoat film 36 is covered with the ITO film, the photoresist is etched even if the overcoat film 36 has a defective portion such as a peen hole. The liquid does not contact the defective part. Further, when the ITO film is etched, the photoresist remains on the pixel electrode 7, the non-panel forming region 4, and the upper layer connection pads 44 and 45 shown in FIG. Even if the coating film 36 has a defective portion P such as a pinhole, the ITO etching solution does not come into contact with the defective portion P. As a result, the ITO etchant for forming the pixel electrode 7 does not soak into the defective portion P of the overcoat film 36. As a result, the Al-ITO battery is connected to the lead line made of Al-based metal, each connection pad, and each terminal. It is possible to prevent defects such as disconnection due to reaction. The protective film 43 remaining on the overcoat film 36 in the non-panel forming region 4 is then cut along the cut line 2. However, even if ITO is embedded in the defective portion P, the protective film 43 does not hinder the function of the liquid crystal display device. Good.
[0016]
Further, in this embodiment, the upper layer connection pads 44 and 45 are formed by leaving the ITO film in an island shape on the upper surfaces of the external connection pads 13 and 16 in the contact holes 41 and 42 and the upper surface of the overcoat film 36 in the periphery thereof. Therefore, the external connection pads 13 and 16 do not come into contact with the etching solution of ITO, and consequently the external connection pads 13 and 16 made of Al-based metal are prevented from being melted by the Al-ITO battery reaction. Can do.
[0017]
In the above embodiment, the case where the pixel electrode 7 is formed on the overcoat film 36 has been described. However, the present invention is also applicable to the case where the pixel electrode is formed on an intermediate insulating film.
[0018]
【The invention's effect】
As described above, according to the present invention, since the protective film made of the ITO film is formed on the entire insulating film in the non-panel forming region, even if there is a defect in the insulating film in the non-panel forming region. Thus, it is possible to prevent disconnection of the wiring under the defective portion. In this case, even if a protective film made of an ITO film is formed over the entire insulating film in the non-panel forming region, there is no problem because the portion corresponding to the non-panel forming region is subsequently cut and removed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an essential part for explaining a method of manufacturing a liquid crystal display panel according to an embodiment of the present invention.
FIG. 2 is an equivalent circuit plan view in a state in which pixel electrodes and the like are formed on a glass substrate having a size corresponding to a plurality of liquid crystal display panels, for explaining a conventional example.
3 is a partial cross-sectional view of a specific structure of the liquid crystal display panel shown in FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Cut line 3 Panel formation area 4 Non-panel formation area 7 Pixel electrode 8 Thin film transistor 13, 16 Output side connection pad 36 Overcoat film 43 Protective film 44, 45 Upper connection pad

Claims (3)

An insulating film is provided on a substrate having a panel forming region and a surrounding non-panel forming region, and a wiring made of an Al-based metal is provided under the insulating film in the panel forming region and the non-panel forming region. In manufacturing an active matrix liquid crystal display panel in which a pixel electrode made of ITO is provided on the insulating film in the formation region,
An ITO film is formed on the insulating film,
The ITO film is wet- etched to form the pixel electrode on the insulating film in the panel formation region, and a plurality of connection pads made of an Al-based metal exposed through an opening formed in the insulating film Forming an upper layer connection pad by leaving the ITO film in an island shape on the insulating film on and in the vicinity of each upper surface, and protecting the whole of the ITO film on the insulating film in the non-panel forming region. A method of manufacturing an active matrix liquid crystal display panel, comprising: forming a film, and then cutting and removing a portion corresponding to the non-panel forming region. 2. The method of manufacturing an active matrix liquid crystal display panel according to claim 1 , wherein the connection pad is connected to a data signal line. 2. The method of manufacturing an active matrix liquid crystal display panel according to claim 1 , wherein the connection pad is connected to a scanning signal line.

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