JPH0553142A - Liquid crystal display panel and production thereof - Google Patents

Abstract

PURPOSE:To provide the liquid crystal display panel which can surely prevent the disconnection of signal lines without drastically increasing the number of stages and the process for production thereof. CONSTITUTION:This liquid crystal panel has the signal line 2a consisting of a chromium layer 14 conductively connecting to a source region 4 via a 1st connecting hole 13a and an aluminum layer 23 on the surface thereof on the front surface side of an interlayer insulating film 13 formed on the front surface side of a thin-film transistor 8. A flush electrode layer 21 formed simultaneously with the chromium layer 14 is conductively connected to a drain region 7 via a 2nd connecting hole 13b. A thick polyimide film layer 31 is formed on the front surface side thereof and a picture element electrode 32 is conductively connected to the flush electrode layer 21 via the connecting hole 31a thereof and its end 32a extends near to the signal line 2b of the adjacent picture element region 1b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display panel and a method of manufacturing the same, and more particularly to a signal line structure technology.

[0002]

2. Description of the Related Art A liquid crystal display panel, which is a typical flat panel display, includes a transparent substrate on one side on which a common electrode is formed and a transparent substrate (matrix array) on the other side on which a large number of pixel electrodes are formed. A liquid crystal is sealed between the two, and the electric potential applied between the common electrode and each pixel electrode is controlled to change the alignment state of the liquid crystal in each pixel region. A typical example thereof is an active matrix system in which a predetermined signal potential is applied to each pixel electrode using a TFT (thin film transistor) or the like, and an example of a matrix array structure used for this is shown in FIG. In this figure, a polycrystalline silicon layer 52 is formed on the surface side of a glass substrate 51, and this polycrystalline silicon layer 52 has a gate electrode 5 on a gate oxide film 54.
By using 5 as a mask, the channel region 53
The source region 56 and the drain region 57 are formed so as to be self-aligned in regions other than. An interlayer insulating film 59 is deposited on the surface side of the TFT 58 having this structure, and the aluminum layer 60 forming the signal line is conductively connected to the source region 56 via the connection hole 59a. The pixel electrode 61 made of ITO is conductively connected to the drain region 57 through the one connection hole 59b. In the pixel region having this configuration, when a predetermined signal potential is applied to the source region 56 via the aluminum layer 60 and a drive potential from the gate line is applied to the gate layer 55, the drain region 57 is applied via the drain region 57. A predetermined signal potential is applied to the pixel electrode 61. As a result, the pixel electrode 6
A potential is applied to the liquid crystal sealed between 1 and the common electrode facing it, and the alignment state of this liquid crystal changes.

[0003]

In the liquid crystal display panel having such a structure, the aluminum electrode 6 forming the signal line is formed.
When the disconnection state occurs at 0 and the display operation is impossible in the entire pixel region to which the signal potential is applied, the display line defect occurs in the liquid crystal display panel. The disconnection is caused by the step breakage that occurs at the step portion and the generation of flakes when the aluminum layer 60 is formed by sputtering. In particular, when the liquid crystal display panel is upsized and the number of pixels is increased, there is a high probability that a disconnection portion is present there, resulting in a decrease in yield and an increase in production cost.

Therefore, in order to prevent the occurrence of a display line defect, for example, it is considered to employ a redundant wiring structure (a plurality of bus lines) having a plurality of wirings. However, if a redundant wiring structure using a plurality of wiring layers is adopted, the region (aperture ratio) that functions as a pixel becomes narrow depending on the arrangement position, which leads to a reduction in the display quality of the liquid crystal display panel and a narrow wiring interval. As a result, new problems such as short-circuiting between wirings easily occur. Of course, the redundant wiring structure is not one that expects an improvement in display quality and is a reluctant means for preventing the occurrence of abnormalities, but conversely, a structure that reduces display quality or reliability can be adopted. Not a thing.

The inventor of the present application proposes to realize a redundant wiring structure by a multilayer structure of signal lines without sacrificing the aperture ratio and the display quality. As this multi-layer structure, first, as a possible structure, an aluminum layer formed by sputtering is patterned to form an aluminum layer on the lower layer side, and then aluminum is formed by sputtering again and patterned, and an upper layer is formed on the aluminum layer on the lower layer side. There is a signal line that overlaps the aluminum layer on the side. If this structure is adopted, since each aluminum layer is patterned in a separate process, even if there is a defect in each resist mask used for it, disconnection does not occur unless the respective defects overlap. Become. However, as long as the same material is used, if there is a defect in the resist mask for patterning the aluminum layer on the upper layer side, the etching process also etches the aluminum layer on the lower layer side from the defect. As a result, it is not possible to completely prevent a wire break accident. In contrast,
A method of interposing a silicon oxide film or the like between each aluminum layer is also conceivable, but a step for forming a silicon oxide film, a step for forming a connection hole, etc. are required, which causes practical problems. is there.

In view of the above problems, the first object of the present invention is to realize the previously proposed multi-layer wiring structure, and to disconnect the signal line without significantly increasing the number of steps. It is to realize a liquid crystal display panel that can be reliably prevented and a method for manufacturing the same.

Further, a second object of the present invention is to realize a liquid crystal display panel and a method of manufacturing the same, which employs a multi-layer wiring structure to improve display quality.

[0008]

Means for Solving the Problem In order to solve the above-mentioned first problem, the means taken in the liquid crystal display panel of the present invention is that the surface side of the interlayer insulating film formed on the surface side of the thin film transistor in the pixel region is formed. Is a signal line conductively connected to the source region of the thin film transistor through the first connection hole,
A pixel electrode conductively connected to the drain region of the thin film transistor through the second connection hole, and the signal line is
The first metal wiring layer includes a first metal wiring layer conductively connected to the source region through the first connection hole, and a second metal wiring layer formed on the surface of the metal wiring layer. , A metal material having a higher etching resistance to an etchant for forming the second metal wiring layer by etching than the metal material forming the second metal wiring layer. The etchant in the present invention means an etching solution used for wet etching and an etching species used for dry etching, and the etching resistance with respect to this etchant is
It means that these etchants are hard to be etched. That is, the metal material forming the first metal wiring layer is less likely to be etched than the metal material forming the second metal wiring layer.

In order to manufacture a liquid crystal display panel having this structure, in the manufacturing method of the present invention, first, a thin film transistor is formed, and then an interlayer insulating film is deposited on the surface side thereof.

Subsequently, after forming a first connection hole and a second connection hole in this interlayer insulating film, a first connection hole and a second connection hole are formed on the surface side of these.
The metal material forming the metal wiring layer is deposited and patterned to form this metal wiring layer. Next, for example, after depositing a material forming the pixel electrode on these surface sides and patterning this to form this pixel electrode, a metal forming the first metal wiring layer is formed on these surface sides. A material is deposited and patterned by chemical etching or the like to form this metal wiring layer.

Next, as a measure taken to solve the second problem, a buried electrode layer formed at the same time as the first metal wiring layer is formed inside the second connection hole described above. The pixel electrode is conductively connected to the drain region through the buried electrode layer.

In order to manufacture the liquid crystal panel having this structure, the buried electrode layer is left inside the second connection hole when the first metal wiring layer is patterned in the manufacturing method described above. do it.

Further, a thick surface protective film is deposited on the surface side of the signal line, and the pixel electrode is conductively connected to the embedded electrode layer through the connection hole of the surface protective film, and its end portion is connected. Is preferably extended to the vicinity of the signal line in the adjacent pixel region.

In manufacturing the liquid crystal display panel having this structure, after the first metal wiring layer and the buried electrode layer are formed, the second metal wiring layer is formed and then the signal line is formed, A thick surface protective film such as polyimide may be formed on this surface side, and the pixel electrode may be formed so as to be conductively connected to the embedded electrode layer through the connection hole.

In the present invention, as the metal material used for the first metal wiring layer, for example, a material containing chromium as a main component can be used. In this case, the second metal wiring layer is mainly made of aluminum. You can use the ingredients.

[0016]

In the present invention, the signal line is the first interlayer insulating film.
Has a multi-layer structure including a first metal wiring layer conductively connected to the source region through the connection hole and a second metal wiring layer formed on the surface thereof. In addition, the first metal wiring layer and the second metal wiring layer are made of different materials, and for example, in wet etching, the etching solution for the metal material forming the second metal wiring layer does not etch the first metal wiring layer. Does not etch the metal material that constitutes it. Therefore, when the second metal wiring layer is formed by patterning,
Even if the mask layer has a defect and the second metal wiring layer is etched to be in a disconnection state, the first metal wiring layer is not attacked and a disconnection portion does not occur there. Therefore, since the disconnection portions of the first and second metal wiring layers do not overlap with each other, even if there is a disconnection in one metal wiring layer, the conductive connection of the disconnection portion is carried by the metal wiring layer on the other side. The signal line itself will not be disconnected.

Here, when the metal material constituting the first metal wiring layer is deposited and patterned, the pixel electrode leaves the buried electrode layer inside the second connection hole, and the pixel electrode forms the buried electrode layer. In the case where the drain region is electrically connected to the drain region, the drain region is covered with the buried electrode layer, and therefore, in the subsequent steps, for example, a post-treatment is performed to remove residues of the wiring layer. Even when applied, the drain region is not damaged. Therefore, it is possible to prevent display defects such as display defects due to defects in the drain region.

Further, when a thick surface protective film is deposited on the surface side of the signal line and the pixel electrode is conductively connected to the embedded electrode layer through the connection hole of the surface protective film, Since the signal line is covered with the thick surface protection film, the signal line and the pixel electrode do not short-circuit, and the adjacent pixel regions do not crosstalk. Therefore, since there are no problems such as display unevenness and an afterimage, the pixel electrode can be arranged even in the vicinity of the signal line in the adjacent pixel region, for example, on the surface protective film immediately above the signal line. As a result, the displayable area (aperture ratio) is expanded, and the display quality is improved.

[0019]

Embodiments of the present invention will now be described with reference to the accompanying drawings.

[Embodiment 1] FIG. 1 is a plan view showing a part of a matrix array of a liquid crystal display panel according to Embodiment 1 of the present invention, and FIG. 2 is a sectional view taken along line I-I thereof.

In this embodiment, as shown in FIG. 1, vertical signal lines 2a, 2b ... And horizontal gate lines 3 are provided.
are wired in a grid pattern, and the pixel regions 1a, 1b, ... Are formed between them.

The structure of the pixel region 1a will be described below as an example. In this pixel area 1a, the signal line 2a
The TFT 8 is formed by the source region 4 electrically connected to the gate line 3, the gate electrode 5 electrically connected to the gate line 3a, and the drain region 7 electrically connected to the pixel electrode 6. Here, the pixel electrode 6 is a transparent electrode made of ITO and is formed over almost the entire surface of the pixel region 1a.

As shown in FIG. 2, the TFT 8 has a sectional structure in which a polycrystalline silicon layer 10 is formed on the surface side of a transparent glass substrate 9 which supports the entire liquid crystal display panel.
Except for the channel region 11 which is an intrinsic polycrystalline silicon region, phosphorus as an n-type impurity is introduced into the polycrystalline silicon layer 10 to form the source region 4 and the drain region 7. Here, phosphorus is introduced into the gate oxide film 1 formed on the surface side of the polycrystalline silicon layer 10.
By using ion implantation with the gate electrode 5 above 2 as a mask, the source region 4 and the drain region 7 are self-aligned. An interlayer insulating film 13 made of a silicon oxide film is deposited on the front surface side of the TFT 8, and a first connecting hole 13a and a second connecting hole 13b are opened therein. The signal line 2a is conductively connected to the source region 4 through the first connection hole 13a. The signal line 2a is connected to the first connection hole 13a.
It has a two-layer structure including a lower chromium layer 14 which is conductively connected to the source region 4 through the aluminum layer 15 and an aluminum layer 15 formed on the surface thereof. One second connection hole 1
The pixel electrode 6 is conductively connected to the drain region 7 via 3b.

In this liquid crystal display panel, as will be described later, the signal line 2a includes the chrome layer 14 and the chrome layer 1.
4 and an aluminum layer 15 formed in a separate process, it is assumed that each of them has a disconnection portion 16 as shown in the section taken along line II-II of FIG. As long as the positions of the disconnection portions 16 do not overlap, the signal line 2a will not be in a disconnection state. That is, since the disconnection state on one side is complemented by the other side on the redundant wiring structure, the signal potential is reliably applied to each source region with respect to all the pixel regions to which the signal line 2a is connected. Line defects are extremely unlikely to occur in this liquid crystal panel.

A method of manufacturing the matrix array of the liquid crystal display panel having such a structure will be described with reference to FIG.

FIG. 4 is a process sectional view showing a part of a method of manufacturing a liquid crystal panel display.

First, as shown in FIG. 4A, after the intrinsic polycrystalline silicon layer 10a is deposited on the surface of the glass substrate 9 by the CVD method, thermal oxidation is performed to form the gate oxide film 12. Form.

Next, a phosphorus-doped polycrystalline silicon layer is formed on the surface side of these by the CVD method and then patterned to leave the gate electrode 5. After that, as shown in FIG. 4B, phosphorus is ion-implanted using the gate electrode 5 as a mask to make the source region 4 and the drain region 7 conductive. Here, an intrinsic polycrystalline silicon portion is left just below the gate electrode 5, and this becomes the channel region 11.

After the TFTs 8 are formed in this manner, the interlayer insulating film 13 is formed on the surface side of these by the CVD method.
Deposit. After that, as shown in FIG. 4C, the first connection hole 13a and the second connection hole 13b are formed above the source region 4 and the drain region 7.

Next, as shown in FIG. 4 (d), chromium is deposited on the surface side of these by a sputtering method to form a chromium layer 14a on the entire surface, and then a resist mask in which a predetermined region is opened. Form the layer 17a. In this state, the entire surface chromium layer 14a is chemically etched with an etching liquid for chromium containing second cerium ammonium nitrate or the like to leave the chromium layer 14.

Next, an ITO layer is deposited on these surfaces by a sputtering method, and then a resist mask layer having a predetermined area opened is formed on the surface. In this state, with an etching solution for ITO mixed with hydrochloric acid, nitric acid, etc.,
The ITO layer is chemically etched to leave the pixel electrode layer 6 as shown in FIG.

Further, as shown in FIG. 4 (f), aluminum is deposited on these surface sides by a sputtering method,
After forming the entire surface aluminum layer 15a, a resist mask layer 17b having a predetermined region opened is formed. In this state, the entire surface aluminum layer 14a is chemically etched with an etching solution for aluminum containing phosphoric acid, nitric acid, etc., and as shown in FIG.
To leave the signal line 2a.

Thus, in this example, the signal line 2a
When making the multi-layer structure, the chrome layer 14 is on the lower side.
On the upper side, an aluminum layer 15 which has no etching ability with respect to the chromium layer and which can be etched with a phosphoric acid / nitric acid-based etching solution is employed.

Therefore, even if the resist mask layer 17b for forming the aluminum layer 15 has a defect and the aluminum layer 15 is broken, the lower chromium layer 14 is not broken. Therefore, the disconnection portion does not occur at the same position of the chrome layer 14 and the aluminum layer 15 and the signal line 2a itself is not disconnected. Therefore, in the liquid crystal display panel of this example, it is difficult for a display line defect due to the disconnection of the signal line 2a to occur. In addition, ITO represented by hydrochloric acid-nitric acid system
The etching solution for aluminum usually has etching ability for the aluminum layer, whereas the etching solution for aluminum typified by phosphoric acid-nitric acid system does not have etching ability for ITO. This example makes maximum use of these relationships, and the aluminum layer 1 is formed after the pixel electrode 6 is formed.
5 is formed, and the step of forming an unnecessary mask layer is omitted. Therefore, even if the redundant wiring structure is adopted for the liquid crystal display panel, the number of manufacturing steps is kept to a minimum, so that the liquid crystal display panel also has cost responsiveness. Moreover, since the formation area of the signal line 2a is not expanded, the aperture ratio is maintained, so that the display quality is not deteriorated.

[Embodiment 2] Next, a liquid crystal display panel according to Embodiment 2 of the present invention will be described with reference to FIG.

FIG. 5 is a cross-sectional view of the matrix array of the liquid crystal display panel according to the second embodiment, and unlike the liquid crystal display panel according to the first embodiment, the second connection hole 1 of the interlayer insulating film 13 is formed.
An embedded electrode layer 21 made of chromium is provided inside 3b, and the pixel electrode 22 is provided through the embedded electrode layer 21.
Are conductively connected to the drain region 7. Since other structures are similar to those of the liquid crystal display panel according to the first embodiment shown in FIG. 1, corresponding parts are designated by the same reference numerals and the description thereof will be omitted. Here, the embedded electrode layer 21 is formed at the same time as the chromium layer 14. Therefore, before forming the pixel electrode and the aluminum layer, the embedded electrode layer 2
Since 1 is formed, the drain layer 7 is not exposed after the formation. Therefore, in the subsequent step, the drain layer 7 is not corroded even if the drain layer 7, that is, an etchant having a corrosive property with respect to silicon is used, so that the restriction on the manufacturing conditions can be relaxed. ..

A method of manufacturing a liquid crystal display panel having this structure will be described.
This will be described with reference to FIG.

FIG. 6 is a process sectional view showing a part of the method of manufacturing the liquid crystal display panel of this example.

Here, the steps until the chromium is deposited by the sputtering method in order to form the chromium layer 14 and the buried electrode layer 21 are the same as those shown in FIG. In this example, instead of the resist mask layer 17a that covers only the formation region of the chrome layer 14, the position above the second connection hole 13b is also covered, as shown in FIG. 6A. A resist mask layer 24a is formed. Therefore, in this state, when the entire surface chromium layer 14a is chemically etched with an etching liquid for chromium containing second ammonium cerium nitrate or the like, the embedded electrode layer 21 can be left as shown in FIG. 6B. ..
Therefore, in this state, since the drain layer 7 is covered with the embedded electrode layer 21 and is not exposed, there is no limitation on the subsequent steps.

Therefore, an example in which aluminum containing copper is used for the aluminum layer 15 will be described. Here, the reason why aluminum containing copper is used is that the signal line 2
This is because when a is also miniaturized, the occurrence of disconnection accidents due to stress, electromigration or the like is prevented. In some cases, aluminum containing silicon may be used.

First, as shown in FIG. 6C, aluminum containing copper is deposited by a sputtering method to form an entire surface aluminum layer 23a. Next, chemical etching is performed in a state in which a predetermined region is covered with a mask layer 24b having a window opened, and as shown in FIG. 6D, the aluminum layer 23 is left on the chromium layer 14 to form the signal line 2a. To do.

In this chemical etching, aluminum is dissolved and removed, but the dissolution rate of copper is slow and copper residue may remain. This residue needs to be removed in order to maintain good light transmittance, and wet etching, plasma etching, or the like is used for this removal. Here, if the drain region 7 is exposed, it will be damaged at the same time, but in this example, the drain region 7 is exposed.
Since is covered with the embedded electrode layer 21, it is not damaged, so that it is possible to prevent generation of point defects and the like due to the damage. Therefore, restrictions on various conditions such as the use of aluminum containing copper and silicon, the use of plasma etching, etc. are eliminated, and the degree of freedom in the configuration and manufacturing of the liquid crystal display panel is increased.

In this example, since the aluminum layer 23 is formed before the pixel electrode 22 is formed,
When the hydrochloric acid-nitric acid-based etching solution for ITO is used as it is as in Example 1, the aluminum layer 23 is also etched. Therefore, in the ITO patterning step, a masking for the aluminum layer 23, an ITO etching solution that does not corrode aluminum, or a dry etching method is used.

[Embodiment 3] Next, a liquid crystal display panel according to a third embodiment of the present invention will be described with reference to FIG.

FIG. 7 is a cross-sectional view of the matrix array of the liquid crystal display panel according to the third embodiment. Since the matrix array has the same structure as that of the liquid crystal display panel according to the second embodiment shown in FIG. It is attached with a code. In the liquid crystal display panel according to the present example, unlike the liquid crystal display panel according to the second embodiment, a thick polyimide layer 31 as a surface protective film is formed on the surface side of the signal line 2a composed of the chrome layer 14 and the aluminum layer 23. The pixel electrode 32 is conductively connected to the embedded electrode layer 21 through the connection hole 31a. That is, the pixel electrode 32 has a structure that is conductively connected to the drain region 7 via the embedded electrode layer 21. Further, the end portion 32a of the pixel electrode 32 extends to the vicinity of the signal line 2b in the adjacent pixel region 1b. The other structures are the same, and therefore their explanations are omitted. Also in this example, aluminum containing copper is used for the aluminum layer 23.

In the liquid crystal display panel having such a structure,
Similar to the liquid crystal display panel according to the second embodiment, due to the redundant wiring structure of the signal line 2a, the display defect is not generated, and the drain region 7 is covered with the embedded electrode layer 21 formed at the same time as the chromium layer 14. Since the aluminum layer 23 and the pixel electrode 32 are formed in this state, the drain region 7 is not damaged in the process of forming them. For example, aluminum containing copper is used for the aluminum layer 23, and after performing patterning by chemical etching or dry etching, there is no problem even if a cleaning step is performed in order to remove residue such as residual copper.
The polyimide layer 31 also has a function of protecting the aluminum layer 23 when the pixel electrode 32 is formed.

Further, in the liquid crystal display panel of this example, the end portions 32a of the pixel electrodes 32 are adjacent to each other in the pixel region 1
It extends to the vicinity of the signal line 2b of b and is in a state of overlapping. In the conventional structure, the end of the pixel electrode is
If the pixel electrodes and the signal lines are arranged close to the signal lines in the adjacent pixel regions, the pixel electrodes and the signal lines are likely to be short-circuited,
Even in a short-circuited state, the electric field generated between them causes the liquid crystal orientation to be disturbed, which causes display unevenness. Therefore, although the aperture ratio is sacrificed, the area where the pixel electrode is formed is reduced. On the other hand, in this example, the thick polyimide layer 31 is interposed between the end portion 32a and the signal line 2b to prevent a short-circuit state, and a strong electric field is provided between them. Does not occur. Therefore, the display deterioration due to the electric field does not occur, so that the adjacent pixel regions 1a and 1b are
There is no crosstalk between them. Therefore, the display quality is improved by arranging the end portion 32a close to the signal line 2b, enlarging the area of the pixel electrode 32, and increasing the aperture ratio. Further, the signal lines 2a and 2b are in contact with the liquid crystal via the polyimide layer 31, and a strong electric field is prevented from being generated between the signal lines 2a and 2b and the common electrode facing each other. For this reason,
Since the disorder of the alignment state of the liquid crystal generated by this electric field is also suppressed, the display quality is further improved.

A method of manufacturing a liquid crystal display panel having such a structure will be described with reference to FIG.

FIG. 8 is a process sectional view showing a part of the method for manufacturing the liquid crystal display panel.

First, the chrome layer 14 and the buried electrode layer 2
Steps up to 1 and the formation of the aluminum layer 23 are the same as those up to FIG. 6D described as the second embodiment, and the description of the steps up to that point is omitted.

In this example, from this state, as shown in FIG.
As shown in (a), a thick polyimide layer 31 having a connection hole 31a is formed above the embedded electrode layer 21.

Then, as shown in FIG. 8B, after the ITO layer 32b is formed on the entire surface by sputtering,
Using a hydrochloric acid-nitric acid-based ITO etching solution,
Chemically etch the O layer. Here, as shown in FIG. 7, the IT is adjusted so that the end portion 32a of the pixel electrode 32 is located above the signal line 2b in the adjacent pixel region 1b.
The O layer is left to ensure the maximum aperture ratio. Here, the polyimide layer 31 also has a function of preventing the aluminum electrode 23 from being etched by the etching liquid for ITO.

In the liquid crystal display panel of this example,
If necessary, dry etching may be adopted for forming each layer. For example, even when using plasma etching or the like for etching the aluminum layer, since the etching resistance of chromium is higher than that of the etching species used for the etching, a disconnection portion does not occur at the same position as the aluminum layer. The effect of the redundant wiring structure is demonstrated.

Further, the arrangement, shape, structure, etc. of each region and each layer are of a nature that should be set to predetermined conditions depending on the size, application, etc. of the liquid crystal display panel to be manufactured, and are not limited. is there.

Furthermore, the sequence of steps after forming the chromium layer is of a nature that should be set in an optimal sequence depending on the structure of the liquid crystal display panel to be manufactured, etching conditions, and the like.

[0056]

As described above, in the liquid crystal display panel according to the present invention, the signal line conductively connected to the source region of the thin film transistor has the first metal wiring layer conductively connected to the source region and the metal wiring layer of the first metal wiring layer. Second formed on the surface
The first metal wiring layer is made of a metal material that is difficult to be etched by the etchant for the second metal wiring layer. Therefore, the present invention has the following effects.

When the second metal wiring layer is formed on the first metal wiring layer, even if a disconnection occurs in the second metal wiring layer due to a defect in the mask used for the patterning, The disconnection does not extend to the first metal wiring layer. Therefore,
Since the probability of a disconnection portion occurring at the same position on the first metal wiring layer and the second metal wiring layer is extremely low, the signal line is less likely to be disconnected. Therefore, it is possible to suppress the occurrence of display line defects due to the disconnection.

Since the above redundant wiring structure can be realized without expanding the formation region of the signal line, the aperture ratio can be secured and the display quality can be maintained.

This is a multi-layer wiring structure in which the second metal wiring layer is formed on the first metal wiring layer, and since the spare signal line is not added to a new position, these mask patterns can be commonly used. Therefore, the process is not complicated.

When the second connection hole is provided with the embedded electrode layer formed at the same time as the first metal wiring layer,
In the subsequent steps, since the drain region is not exposed, the drain region is not damaged during the process even if various kinds of processes are performed, so that the display quality is improved.

When a thick surface protective film is deposited on the surface of the signal line and the end of the pixel electrode is extended to the vicinity of the signal line in the adjacent pixel region, the aperture ratio is increased, The display quality can be improved. Here, since the signal line is covered with the thick surface protection film, there is no influence of the electric field around the signal line, so that the problem of crosstalk to the adjacent pixel region does not occur.

[Brief description of drawings]

FIG. 1 is a plan view showing a part of a matrix array of a liquid crystal display panel according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II of FIG.

FIG. 3 is a sectional view taken along line II-II in FIG.

4A to 4F are process cross-sectional views showing a part of a process of manufacturing a matrix array of a liquid crystal display panel according to a first embodiment of the present invention.

FIG. 5 is a sectional view showing a part of a matrix array of a liquid crystal display panel according to a second embodiment of the present invention.

6A to 6D are process cross-sectional views showing a part of a process of manufacturing a matrix array of a liquid crystal display panel according to a second embodiment of the present invention.

FIG. 7 is a sectional view showing a part of a matrix array of a liquid crystal display panel according to a third embodiment of the present invention.

8A and 8B are both Embodiment 3 of the present invention.
FIG. 6 is a process cross-sectional view showing a part of a process for manufacturing a matrix array of the liquid crystal display panel according to the above.

FIG. 9 is a cross-sectional view showing a part of a matrix array of a conventional liquid crystal display panel.

[Explanation of symbols]

 1a, 1b ... Pixel area 2a, 2b ... Signal line 3a, 3b ... Gate line 4 ... Source area 5 ... Gate electrode 6, 22, 22, 32 ... Pixel electrode 7 ... Drain region 8 ... TFT 14 ... Chromium layer (first metal wiring layer) 15, 23 ... Aluminum layer (second metal wiring layer) 21 ... Embedded electrode layer

Claims (9)

[Claims] 1. A signal line conductively connected to a source region of the thin film transistor through a first connection hole on a surface side of an interlayer insulating film formed on a surface side of the thin film transistor in the pixel region, and a second line thereof. A pixel electrode conductively connected to the drain region of the thin film transistor through the connection hole, and the signal line conductively connected to the source region through the first connection hole. And a second metal wiring layer formed on the surface of the metal wiring layer, wherein the first metal wiring layer has the etching resistance against an etchant for etching the second metal wiring layer. A liquid crystal display panel, which is made of a metal material higher than that of the metal material forming the second metal wiring layer. 2. The metal material forming the second metal wiring layer according to claim 1, which can be wet-etched with an etching solution that is non-etching to the metal material forming the first metal wiring layer. A liquid crystal display panel characterized by: 3. The second connection hole according to claim 1 or 2, wherein the second connection hole includes an embedded electrode layer formed at the same time as the first metal wiring layer, and the embedded electrode layer is interposed therebetween. The liquid crystal display panel, wherein the pixel electrode is conductively connected to the drain region. 4. The thick surface protection film according to claim 3, wherein a thick surface protection film is deposited on the front surface side of the signal line, and the pixel electrode is electrically conductive to the embedded electrode layer through a connection hole of the surface protection film. A liquid crystal display panel, wherein the liquid crystal display panel is connected and has its end portion extended to the vicinity of a signal line in an adjacent pixel region. 5. The liquid crystal display panel according to claim 4, wherein the surface protective film is made of a polyimide resin. 6. The metal material forming the second metal wiring layer according to claim 1, wherein the metal material forming the first metal wiring layer contains chromium as a main component. Is a liquid crystal display panel characterized by mainly containing aluminum. 7. The method for manufacturing a liquid crystal display panel according to claim 1, wherein after forming the thin film transistor, a step of depositing the interlayer insulating film on a front surface side of the thin film transistor; The first connection hole and the second
The step of forming the connection holes of the
The step of depositing the metal material for forming the metal wiring layer, patterning the metal material to form the metal wiring layer, and thereafter applying the material for forming the pixel electrode to the surface side of these. And patterning it to form this pixel electrode, and subsequent to this step, or
Prior to this step, a step of forming a metal wiring layer by depositing a metal material forming the second metal wiring layer on these surface sides and patterning the metal material by etching. A method of manufacturing a characteristic liquid crystal display panel. 8. A method for manufacturing a liquid crystal display panel according to claim 3, wherein after forming the thin film transistor, an interlayer insulating film is deposited on a surface side thereof.
A step of forming the first connection hole and the second connection hole in the interlayer insulating film, and a metal material forming the first metal wiring layer is deposited on the surface side of these and patterned. To form this metal wiring layer,
The step of leaving the buried electrode layer inside the connection hole, and thereafter, depositing the material forming the pixel electrode on these surface sides and patterning the material to form the pixel electrode. And, following this process, or
Prior to this step, a step of forming a metal wiring layer by depositing a metal material forming the second metal wiring layer on these surface sides and patterning the metal material by etching. A method of manufacturing a characteristic liquid crystal display panel. 9. A method for manufacturing a liquid crystal display panel according to claim 4, comprising the steps of forming the thin film transistor and then depositing an interlayer insulating film on the front surface side thereof.
A step of forming the first connection hole and the second connection hole in the interlayer insulating film, and a metal material forming the first metal wiring layer is deposited on the surface side of these and patterned. To form this metal wiring layer,
The step of leaving the embedded electrode layer inside the connection hole, and depositing a metal material forming the second metal wiring layer on the surface side of these, patterning this by etching,
The step of forming this metal wiring layer, the step of depositing the material forming the surface protective film on these surface sides and then forming the connection holes therein, and forming the pixel electrode on these surface sides A step of depositing a material, patterning the material, and forming the pixel electrode, and a method for manufacturing a liquid crystal display panel.