JP2002107757A - Manufacturing method for liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device having a light weight, a high aperture ratio, and high pixel density. SOLUTION: A pair of wiring 102a, 102b is formed on a resin substrate, and then the spaces T2 between the wiring 102a, 102b and pixel electrodes 103a, 103b to be connected with the wiring 102a, 102b via MIM elements 104a, 104b are designed larger than the maximum dimensional variation T1 in the manufacturing process of the liquid crystal display device. Further, the space T3 between a pair of the wiring 102a, 102b is designed smaller than the maximum dimensional variation T1, and the space T4 between the pixel electrodes 103a, 103b is designed smaller than the maximum dimensional variation T1. Thus, an aperture ratio is improved.

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 (hereinafter, abbreviated as LCD) used as various display devices such as a display for information equipment.
And a method for producing the same.

More specifically, an active element (Metal Insulator Metal: hereinafter abbreviated as MIM) having a three-layer structure of a metal film, an insulating film and a metal film formed on a resin substrate.
The present invention relates to a method for manufacturing a liquid crystal display device (hereinafter, abbreviated as MIM-LCD) having the following.

[0003]

2. Description of the Related Art In recent years, liquid crystal display devices (hereinafter abbreviated as LCDs) used as displays for information devices have been mounted on portable telephones and portable information terminals in recent years. There is a strong demand for improved portability. For this reason, LCDs using a resin substrate instead of a glass substrate as a substrate (hereinafter, referred to as a resin substrate LCD) have been put to practical use. This resin substrate LCD has the advantages of being thin, lightweight, and resistant to cracking.

[0004] In order to further improve the display quality, an LCD in which active elements such as TFTs (thin film transistors) and MIMs are formed on a resin substrate (hereinafter abbreviated as AMLCD).
Is also under development. Thus, when a resin substrate is used, the low heat resistance of the resin substrate causes
There are restrictions on the temperature of the LCD manufacturing process. Therefore, in the conventional example actually reported as a display, a two-terminal element such as a MIM is more often used instead of a three-terminal element such as a TFT.

[0005] Publication "Journal of the SID 5/3 1997"
Pp 275-281 describes a method of manufacturing a two-terminal device using silicon nitride on a PES (polyethersulfone) substrate by a manufacturing process at a temperature of 200 ° C. or less and forming an LCD driven by the two-terminal device. Has been described. This LCD is a display in the transmission monochrome mode of 108 × 96 pixels, and the diagonal length of the display area is as small as about 40 mm.

[0006] Also, pp14 of the publication "SID 1999 Digest"
17 to 17 describe a method of forming an MIM element-driven LCD using a PES substrate, as in the above-described LCD. This LCD is a 96 x 128 pixel transmissive LCD
In addition, color display using a color filter is possible. However, this LCD has an aperture ratio of 45.
%, And the contrast ratio is only about 10: 1. Also, the diagonal length of the display area is only about 50.8 mm,
After all it is small.

[0007]

As described above, forming an active element on a resin substrate involves a problem peculiar to the resin substrate different from the case where a glass substrate is used. The most typical problem is that the heat resistance of the resin substrate is low,
The manufacturing process temperature is limited low. However, there is already a prospect of solving this problem by improving manufacturing process technology.

Separately, an LCD using a resin substrate
Currently, the biggest obstacle to the practical use of is that the resin substrate expands and contracts during the manufacturing process, which causes a dimensional change in the resin substrate. In this case, expansion and contraction due to temperature changes are a problem, but at the same time, expansion and contraction caused by the resin substrate absorbing and releasing moisture and an organic solvent are also serious problems. This means
It is pointed out in the publication "SID 1998 Digest", pp 293-296. In the prior art, a large LCD panel using a resin substrate or a high-definition LCD
Panel fabrication has been hindered.

FIG. 6 is a graph showing the change in the expansion and contraction rate of the resin substrate in each step of the MIM-LCD manufacturing process. At this time, since the MIM-LCD manufacturing process temperature can be set to 150 ° C. at the maximum, the problem of the heat resistance of the resin substrate is solved. However, as shown in FIG. 6, the expansion and contraction of the resin substrate, which may be caused by the absorption and release of moisture and the like during the LCD manufacturing process, are observed, and the expansion and contraction ratio has a considerably large value of about 200 ppm on average. are doing. Here, the expansion / contraction ratio is a certain 2
The amount of dimensional change of the resin substrate between points is defined as a value obtained by dividing the amount of dimensional change by the distance between two points at the time of reference. Here, the dimension at the time of exposure of the lower electrode, whose pattern dimension is first determined in the LCD manufacturing process, is defined as a reference distance. In FIG. 6, the negative expansion / contraction ratio indicates the contraction ratio of the resin substrate, and the positive expansion / contraction ratio indicates the expansion ratio of the resin substrate.

As shown in FIG. 6, an LCD was manufactured on a plurality of resin substrates under the same process conditions, but a variation of 100 ppm or more for each resin substrate was observed. In some cases, anisotropy in which expansion and contraction in a specific direction was increased was also observed. A similar tendency has been observed for other types of resin substrates that can be used in the above-mentioned process, and at present, there is no resin substrate having sufficient characteristics for expansion and contraction of the substrate during the process.

In order to prevent the expansion and contraction of the resin substrate, the development of a substrate made of a resin that does not absorb various solvents or a resin whose dimensional change is very small when absorbed, and the penetration of the solvent into the substrate base material itself by improving the substrate coating. Although a solution to prevent such a problem has been studied, a resin substrate having sufficient characteristics has not yet been realized. Therefore, at present, as long as a resin substrate is used, a dimensional change due to expansion and contraction of the resin substrate between processes is inevitable, and it is also difficult to control the amount of expansion and contraction of the resin substrate. Particularly, in the active element forming process, a plurality of photo processes are required, so that it is necessary to increase the required alignment accuracy.
Fabrication of D is very difficult.

In the manufacturing process shown in FIG. 6, three photo steps are required until the pixel electrode is formed. Since the designed pattern shape and its dimensions are reflected from the mask to the LCD at the time of the exposure process, at least at the time of these three exposures, the deviation between the patterns due to the dimensional change of the substrate is within the range of the designed margin. Must be within.

When an AMLCD is manufactured using a glass substrate, the size of this margin is designed on the assumption that it is usually 3 to 5 ppm or less when the dimensional change in the process is represented by the expansion and contraction ratio. . On the other hand, as shown in FIG.
It is necessary to estimate to about 00 ppm.

That is, in the case of a glass substrate, one side is 8
Even when a substrate of 00 mm is used, 800 mm × 5 ppm = 4
It is sufficient to design such that a margin of μm is secured. On the other hand, in the case of a resin substrate, even if the side of the substrate is 100 mm, 100 mm × 200 pp
It is necessary to secure a margin of m = 20 μm.
If a large margin is secured in this way, the effective display area is reduced and the aperture ratio is reduced, so that the display quality is sacrificed. In particular, in a high-definition LCD or a color LCD that performs color display by dividing pixels, the size per pixel is small, so that the effect on the reduction of the aperture ratio is large. Also, in a large LCD, the amount of expansion and contraction of the substrate itself becomes large, so that a large effect is inevitable. For this reason, in the prior art, it was extremely difficult to produce a high-definition LCD or a large LCD using a resin substrate.

FIG. 7 is an enlarged view of the vicinity of a pixel of an active matrix substrate 30 having a general structure manufactured by a method of manufacturing a liquid crystal display device according to the prior art. A signal transmission wiring 21 whose surface is anodized on a resin substrate 20
The pixel electrode 24 and the upper electrode 22 are formed in this order by film formation and patterning. At this time, the region 23 where the wiring 21 and the upper electrode 22 intersect operates as an MIM element. Wiring 21, pixel electrode 24 and upper electrode 22
Since the shape is determined by each different photo process, in the prior art, the required function is not impaired so that the position is not shifted between the patterns.
Designed with a sufficiently large margin. Therefore, the aperture ratio is extremely low as compared with an LCD made of a general glass substrate.

For example, consider the pixel electrode 24. Since the pixel electrodes 24 adjacent in the vertical direction (the vertical direction in FIG. 7) are formed simultaneously by one photo process, the space 26 between these pixel electrodes 24 is determined in consideration of the dimensional change of the resin substrate 20. do not have to. However,
Since the photo process for forming the pixel electrode 24 and the photo process for forming the wiring 21 are different processes, there is a possibility that the dimensions of the resin substrate 20 have changed between the two photo processes.

Therefore, it is necessary to secure a large margin exceeding the dimensional change of the resin substrate 20 in the space 25 between the pixel electrode 24 and the wiring 21 so that they do not overlap each other. For this reason, the prior art AM substrate 30 shown in FIG. 7 is designed to have a very large space 25 on both sides in the horizontal direction of the pixel electrode 24 (the left-right direction in FIG. 7). This is a factor that significantly reduces the aperture ratio.

Further, even when the resin substrate 20 is greatly changed in size, a sufficiently large margin is provided also in this portion so that the wiring 21 and the upper electrode 22 surely overlap and the upper electrode 22 and the pixel electrode 24 surely overlap. Need to be secured. This is also one factor in lowering the aperture ratio.

As described above, when fabricating the AM substrate 30 driven by the active matrix using the resin substrate 20,
Dimensional change due to expansion and contraction of the resin substrate 20 becomes a problem, and a design with a sufficiently large margin is required. When the AM substrate 30 is formed based on such a design, the aperture ratio of the obtained LCD is significantly reduced. In particular, when the size per pixel is small, the effect on the reduction of the aperture ratio is large. In addition, since the amount of expansion and contraction increases as the substrate size increases, it is difficult to increase the size of the LCD, increase the density of pixels, and achieve colorization using color filters while ensuring high display quality. Was.

Accordingly, an object of the present invention is to provide a method of manufacturing a liquid crystal display device which can overcome the above-mentioned problems and can manufacture a liquid crystal display device using a large resin substrate with high display quality. .

Still another object of the present invention is to provide a liquid crystal display device having a light weight, a high aperture ratio, and a high pixel density.

[0022]

According to the present invention, a pair of wirings running side by side in the same direction on a resin substrate and a pair of pixels arranged on both sides of the pair of wirings are provided. A plurality of patterns each including an electrode and an active element disposed between the wiring and the pixel electrode and connected to the wiring and the pixel electrode are formed in a matrix, and the wiring and the pixel electrode are formed in separate steps. A manufacturing method,
A method of manufacturing a liquid crystal display device, characterized in that an interval T2 between a wiring connected by the active element and a pixel electrode is designed to be larger than a maximum dimensional change T1 of the resin substrate in a manufacturing process of the liquid crystal display device. is there.

According to the present invention, a pair of wirings running in the same direction adjacent to each other, a pair of pixel electrodes disposed on both sides of the pair of wirings, a wiring and a pixel electrode are formed. The active elements to be connected are formed in different steps. First, a pair of wires are formed on a resin substrate,
Next, in a state where the distance T2 between the wiring and the pixel electrode connected via the active element is designed to be larger than the maximum dimensional change T1 in the manufacturing process of the liquid crystal display device of the resin substrate, the pair of pixel electrodes To form As described above, by securing a sufficient margin between the wiring connected via the active element and the pixel electrode, even if the resin substrate changes its dimensions due to factors such as absorption and release of moisture. In addition, problems such as direct contact between the wiring and the pixel electrode are prevented.

Further, the present invention is characterized in that an interval T3 between a pair of wirings running side by side adjacent to each other is designed to be smaller than the maximum dimensional change T1.

According to the present invention, it is not necessary to consider the influence of expansion and contraction of the resin substrate in the interval between each pair of wirings formed simultaneously in one photo step. The interval T3 is designed to be smaller than the maximum dimensional change amount T1. Therefore, even if a sufficiently large margin is secured between the wiring connected through the active element and the pixel electrode, the aperture ratio can be improved as compared with the liquid crystal display device of the prior art. That is, when a liquid crystal display device having the same size and the same pixel density as the liquid crystal display device of the prior art is formed, the aperture ratio is improved and the display quality is improved. Further, if a liquid crystal display device having the same aperture ratio as the liquid crystal display device of the prior art is manufactured, a larger panel size and a higher pixel density can be realized.

Further, according to the present invention, the distance T3 between a pair of wirings running side by side adjacent to each other is set to one of the maximum dimensional change T1.
/ 2 or less.

According to the present invention, it is not necessary to consider the effect of expansion and contraction of the resin substrate in the interval between a pair of wirings formed simultaneously in one photo process. T3 is designed to be 以下 or less of the maximum dimensional change amount T1. Therefore, even if a sufficiently large margin is secured between the wiring connected through the active element and the pixel electrode, the aperture ratio can be improved as compared with the liquid crystal display device of the prior art. That is, if a liquid crystal display device having the same size and the same pixel density as the liquid crystal display device of the prior art is formed, the aperture ratio is improved and the display quality is improved. Further, if a liquid crystal display device having the same aperture ratio as the liquid crystal display device of the prior art is manufactured, a larger panel size and a higher pixel density can be realized.

Further, the present invention is characterized in that the interval T4 between the pixel electrodes of each pattern adjacent to each other is designed to be smaller than the maximum dimensional change T1.

According to the present invention, it is not necessary to consider the influence of expansion and contraction of the resin substrate in the interval T4 between the pixel electrodes of the patterns which are simultaneously formed in one photo step and are adjacent to each other. The distance T4 between the pixel electrodes is designed to be smaller than the maximum dimensional change T1. Therefore, even if a sufficiently large margin is secured between the wiring connected through the active element and the pixel electrode, the aperture ratio can be improved as compared with the liquid crystal display device of the prior art. That is, if a liquid crystal display device having the same size and the same pixel density as the liquid crystal display device of the prior art is formed, the aperture ratio is improved and the display quality is improved. Further, if a liquid crystal display device having the same aperture ratio as the liquid crystal display device of the prior art is manufactured, a larger panel size and a higher pixel density can be realized.

Further, the present invention is characterized in that the interval T4 between the pixel electrodes of each pattern adjacent to each other is designed to be 以下 or less of the maximum dimensional change T1.

According to the present invention, it is not necessary to consider the effect of expansion and contraction of the resin substrate in the interval T4 between the pixel electrodes of each pattern formed simultaneously in one photo step and adjacent to each other. The distance T4 between the pixel electrodes is designed to be 以下 or less of the maximum dimensional change T1. Therefore,
Between the wiring connected via the active element and the pixel electrode,
Even if a sufficiently large margin is secured, the aperture ratio can be improved as compared with the liquid crystal display device of the prior art.
That is, if a liquid crystal display device having the same size as the liquid crystal display device of the prior art and the same pixel density is formed,
The aperture ratio is improved, and the display quality is improved. Further, if a liquid crystal display device having the same aperture ratio as the liquid crystal display device of the prior art is manufactured, a larger panel size and a higher pixel density can be realized.

Further, according to the present invention, the active element includes a metal film,
The insulating film and the metal film are MIM elements stacked in this order.

According to the invention, the active element is a MIM element. Since the MIM element can be formed by a relatively low-temperature manufacturing process as compared with the TFT element, a resin substrate having a low heat-resistant temperature can be used instead of a glass substrate. Further, since a low-temperature manufacturing process is sufficient, the amount of dimensional change of the resin substrate during the entire manufacturing process of the liquid crystal display device can be small, and the distance between the wiring connected via the MIM element and the pixel electrode can be increased. No need to take. Therefore, the aperture ratio is improved, and the density of pixels can be increased.

Further, the present invention is characterized by including a step of forming a color filter. According to the present invention, even if a resin substrate is used, a high-quality color liquid crystal display device in which the aperture ratio is improved and the density of pixels is realized can be obtained.

[0035]

FIG. 1 is an enlarged view showing the vicinity of a pixel of an active matrix substrate 101 of an MIM element driven liquid crystal display device manufactured by a method of manufacturing a liquid crystal display device according to an embodiment of the present invention. is there. An active matrix substrate (hereinafter, referred to as an AM substrate 101) for driving the MIM element includes a pair of wirings 102a and 102b running in parallel in the same direction on a resin substrate 106 so as to be adjacent to each other.
A pair of pixel electrodes 103a, 103b disposed on both sides of the pair of wirings 102a, 102b,
02a, 102b and each pixel electrode 103a, 103b
A pair of MIs interposed between and electrically connecting the wirings 102a and 102b and the pixel electrodes 103a and 103b.
One pattern 1 composed of M elements 104a and 104b
05 are formed in a matrix.

The pair of wirings 102a, 102b
Are collectively referred to as a wiring 102, and the pair of pixel electrodes 103a and 103b are collectively referred to as a pixel electrode 1
03 and the pair of MIM elements 104a and 104b.
Are collectively referred to as an MIM element 104.

The AM substrate 101 will be described in more detail. A pair of wirings 102a,
The pair 102b is formed on the resin substrate 106 in a state where the pair 102b runs in parallel in the vertical direction (the vertical direction in FIG. 1). Lower electrode 107 of MIM element 104a, 104b
From each of the wirings 102a and 102b corresponding to each pixel,
It is formed to be branched on both sides in the horizontal direction (the left-right direction in FIG. 1) substantially perpendicular to the vertical direction. An upper electrode 108 is formed orthogonal to the lower electrode 107. Lower electrode 107 and upper electrode 1
08 operates as the MIM element 104.
Further, a pixel electrode 103 is formed to be connected to both ends of the upper electrode 108.

The AM substrate 101 includes a pair of wires 102
The columns of the pixel electrodes 103a and 103b connected to the both sides of the a and b via the MIM elements 104a and 104b,
The configuration is formed symmetrically with respect to an axis 109 passing through the center between the wirings 102a and 102b.

As compared with the structure of the AM substrate 30 of the prior art shown in FIG. 7, the AM substrate 101 of the present embodiment has the pixel electrodes 103 and the wirings 102 arranged in the left and right directions for each column. Therefore, in the AM substrate 101, there are a portion where the pixel electrodes 103 are adjacent to each other, such as between the columns A and B in FIG. 1, and a portion where the wirings 102 are adjacent to each other, as between the columns B and C. .

At this time, the pixel electrode 103 and the wiring 10 connected to the pixel electrode 103 via the MIM element 104
The interval T2 between the two basically secures a large margin similarly to the prior art AM substrate 30 shown in FIG.

However, since the pixel electrodes 103 are formed in the same photo-etching step at the interval T4 between the adjacent pixel electrodes 103 without the MIM element 104 therebetween, the expansion and contraction of the resin substrate 106 is taken into consideration. There is no need to secure large margins.

Since the pair of wirings 102a and 102b are formed by the same photo-etching process, there is no need to consider the influence of expansion and contraction of the resin substrate 106. Therefore, a large margin is not secured in the interval T3 between the pair of adjacent wirings 102, such as between the rows B and C.

Therefore, the AM substrate 101 of the present invention
Since the pixel electrode 103 is designed to be larger than the AM substrate 30 of the prior art by the area of the hatched area 114, the aperture ratio is improved.

The area of the region 114 is the same as that of the prior art.
The interval 111 required for the M substrate 30 is large, and the longer the pixel electrode 103 in the vertical direction (the vertical direction in FIG. 1), the larger the interval. That is, when the shape of the pixel electrode 103 is a rectangle having a long side in the vertical direction substantially along the wiring 102, the region 17 becomes large, and the effect of improving the aperture ratio is large.

Further, in the MIM-LCD which performs color display using a color filter, since color display is performed by an additive color mixture method, pixels are divided and compared with a monochrome display or a color display using a subtractive color mixture method. The size becomes smaller. Therefore, the prior art MIM-LCD
When colorizing is used, the pixel density must be made coarse in order to greatly reduce the aperture ratio or prevent the aperture ratio from decreasing, and there is a problem that the display quality is significantly reduced.

However, when a color filter is provided on the AM substrate 101 of the present invention, a thin and lightweight color MIM-LCD having a sufficient display quality can be obtained.

In Japanese Patent Application Laid-Open No. H10-142629, similarly to the present invention, columns of pixel electrodes connected via active elements on both sides of a pair of wires running in parallel are formed symmetrically. Examples of AM substrates having different shapes have been reported.

However, in the present invention, in order to achieve the purpose of forming an active element on a resin substrate, Japanese Patent Laid-Open No.
In addition to the structure of the AM substrate described in Japanese Patent No. 42629, the distance T2 between the wiring 102 and the pixel electrode 103 is designed to exceed the maximum dimensional change T1 due to expansion and contraction of the resin substrate during the manufacturing process. Interval T3 between 102
Are designed to be smaller than the maximum dimensional change T1, and the interval T4 between the adjacent pixel electrodes 103 is designed to be smaller than the maximum dimensional change 1.

As a result, the AM substrate 101 is
In addition to the effect of improving the viewing angle characteristics obtained by the AM substrate disclosed in JP-A-142629, the effects of increasing the aperture ratio and improving the display quality are also achieved. Thus, the AM substrate 1 of the present invention
No. 01 is a novel invention capable of obtaining a completely different effect, although it has a structure similar to the AM substrate described in JP-A-10-142629.

Next, a method for manufacturing a liquid crystal display device according to an embodiment of the present invention will be described. The method for manufacturing a liquid crystal display device according to the present invention includes a design step of designing a pattern 105 formed on a resin substrate 106 and a wiring forming step of forming a pair of wirings 102 a and 102 b on the resin substrate 106 based on the design. And a pair of MIM elements 104a, 104
b) and a pixel electrode forming step of forming a pair of pixel electrodes 103 a and 103 b on the resin substrate 106.

FIG. 2 is a view showing a state after the wiring forming step, and FIG. 3 is a view showing a state after the MIM element forming step. PES (polyethersulfone) substrate 10 having a length of 150 mm, a width of 200 mm, and a thickness of 250 μm, on both surfaces of which a coating process such as a gas barrier or a hard coat is applied.
6, a film thickness of 200 n was formed by magnetron sputtering.
m of Ta film was formed.

The resin substrate 106 is not particularly limited, but preferably has excellent heat resistance, light transmittance and chemical resistance. Further, as a film material on the resin substrate 106,
Other than Ta, Al, Mo or Si may be used,
Alternatively, these alloy materials may be used. Further, the film thickness is desirably in the range of about 50 nm to 500 nm. In addition, during film formation, depending on temperature, plasma, etc.
Care must be taken so that the resin substrate 106 is not damaged. In this embodiment, the resin substrate 106 during film formation is used.
By keeping the temperature of the resin substrate at 180 ° C. or less, the resin substrate 1
The damage to 06 was suppressed.

Next, by a series of photo-etching steps such as resist coating, pre-baking, exposure, development, post-baking, etching and resist peeling, T
The film a was patterned. This state is shown in FIG. By patterning the Ta film in this manner, a pair of wirings 102a and 102b running in the same direction and adjacent to each other were formed on the resin substrate 106.

In this embodiment, the display area is 120 m long.
The wiring 102 was formed in a rectangular shape having a size of m, 160 mm in width, and 200 mm in diagonal shape and having a shape corresponding to an MIM-LCD having 600 × 800 pixels. At this time, the display area per pixel is 200 μm × 200 μm. Assuming that the maximum expansion and contraction rate of the resin substrate 106 is 200 ppm, the maximum dimensional change T11 in the vertical direction (the vertical direction in FIG. 2) is 120
mm × 200 ppm = 24 μm, and the maximum dimensional change T12 in the horizontal direction (the horizontal direction in FIG. 2) is 160 mm
× 200 ppm = 32 μm. Therefore, in the present embodiment, the maximum dimensional change amounts T11 and T1 in the vertical and horizontal directions are set as the allowable amounts for the positional deviation.
It was designed to be 35 μm larger than 2. That is, the wiring 102
And the pixel electrode 104 formed in the next pixel electrode forming step
The design was made to secure a margin of 35 μm as the interval T2 between.

The maximum expansion ratio refers to the maximum value of the contraction ratio of the resin substrate 106 between the steps shown in FIG. That is, the maximum dimensional change amounts T11 and T12 are AM
It refers to the maximum amount of shrinkage between each step of the resin substrate 106 in the manufacturing process of the substrate 101.

On the other hand, since a large margin as described above is not required between the pair of wirings 102a and 102b formed simultaneously in one wiring forming step, the interval T3 between the wirings 102a and 102b is set to be smaller. , 5 μm.
Further, since a large margin as described above is not required between the pair of pixel electrodes 103a and 103b formed simultaneously in one pixel electrode forming step, each pixel electrode 103
The interval T4 between a and 103b was designed to be 5 μm.

In this step, there is no particular difference from the ordinary process technology using a glass substrate. However, it should be noted that the substrate itself is constantly expanding and contracting. The etching for forming the pattern of the Ta film was performed by dry etching using CF ₄ plasma.

On the surface of the patterned wiring 102,
Anodization was performed in a 0.01% aqueous citric acid solution to form an oxide film of about 50 nm. The thickness of the oxide film is desirably set within a range of about 10 to 200 nm according to the device characteristics to be obtained. In addition, a solution for performing anodization may use an organic acid other than citric acid, an inorganic acid, a salt thereof, or the like. Further, an insulating film such as silicon nitride may be newly formed without performing anodic oxidation.

Thereafter, in order to form the upper electrode 108 by the magnetron sputtering method, Cr is changed to 100 n.
The film was formed to a thickness of about m. The material used for the upper electrode 108 is not limited to Cr, but may be a metal such as Mo, Al, or Ti.

After the formation of the Cr film, resist coating, pre-baking, exposure, development, post-baking, etching,
The Cr film was patterned by a series of photoetching steps such as resist stripping and the like to form the upper electrode 108. Note that there is a possibility that a positional shift may occur between the wiring 102 and the already formed wiring due to a dimensional change of the resin substrate. Therefore, the design is made with a margin of 35 μm as described above. The alignment of the mask at the time of exposure was performed such that the displacement at the center of the AM substrate 101 was minimized. At this time, since the resin substrate 106 expanded due to the inclusion of moisture during the process, in the pixel region on the edge side of the display region, a pattern between the wiring 102 and the pattern of the mask for forming the upper electrode 108 was formed. Had a maximum displacement of about 20 μm in both the vertical and horizontal directions.

Next, in order to form the pixel electrode 103, I
A TO film was formed to a thickness of 150 nm. The thickness of this ITO film is desirably about 50 to 500 nm. As a film forming means, a sputtering method, a vapor deposition method, an ion plating method, or the like can be used. However, a means exhibiting good coverage characteristics and capable of forming a high-quality film at a low temperature is desirable. The material of the pixel electrode 103 is IT
It is not limited to O, and another transparent conductor such as tin oxide may be used. Further, it is also possible to manufacture a reflective mode LCD by using the pixel electrode 103 as a reflective electrode using a metal such as Al or Ag. In addition, ITO
After the pixel electrode 103 is formed, a reflective electrode is formed on a part of the surface of the pixel electrode 103, and a transflective mode LCD can be obtained.

After the formation of the ITO film, the ITO film is patterned as shown in FIG. 3 by a series of photo-etching steps such as resist coating, pre-baking, exposure, development, post-baking, etching and resist peeling. The pixel electrode 103 was formed. At this time, since there is a possibility that a positional shift may occur between the wiring 102 already formed in the wiring forming process due to a dimensional change of the resin substrate 106, as described above, the distance between the wiring 102 and the pixel electrode 103 may be reduced. As T2, a design in which a margin of 35 μm larger than the maximum dimension change T12 in the horizontal direction was ensured, and the pixel electrode 103 was formed based on this design.

The alignment at the time of exposure for forming the pixel electrode 103 was performed such that the displacement at the center of the panel was minimized. At this time, since the resin substrate 106 has expanded due to moisture absorption or the like, in the pixel region at the end of the display region, the gap between the already formed upper electrode 108 and the pattern of the mask for forming the pixel electrode 103 is formed. Had a maximum displacement of about 10 μm in both the vertical and horizontal directions.

Here, since the adjacent pixel electrodes 103 are formed simultaneously in one pixel electrode forming step, the interval T4 between the pixel electrodes 103 has a large margin in consideration of the dimensional change of the resin substrate during the process. Does not need. Therefore, the interval T4 between the pixel electrodes 103 is set to 5 μm.
m.

That is, as described above, the interval T3 between the interconnects 102 adjacent to each other is designed to be 5 μm, and the interval T4 between the pixel electrodes 103 adjacent to each other is designed to be 5 μm. The pixel electrode 103 per pixel can be enlarged by the area of the hatched area 114 as compared with the prior art AM substrate 30 shown in FIG. 7, and the ratio of the effective display area (aperture ratio) is improved. . In the present embodiment, the interval T3 between the wirings 102 and the interval T4 between the pixel electrodes 103 can be set to 5 μm.
As a result, the aperture ratio could be improved by about 12 to 15%.

Thereafter, a liquid crystal display panel was formed by a normal process corresponding to the resin substrate, and a liquid crystal display device was obtained.
In this embodiment, the steps after the pixel electrode forming step are also one step.
Since the process was performed at a process temperature of 80 ° C. or less, the resin substrate 10
No effect on 6 was seen.

The A designed and manufactured as described above
The M substrate 101 had a total displacement of about 30 μm between the wiring 102 and the pixel electrode 103 due to the dimensional change of the resin substrate 106 during the manufacturing process, as compared with the position at the time of design. . However, in the manufacturing method of the liquid crystal display device of the present embodiment, the MIM having a high brightness and high display quality is designed despite a very large margin of 35 μm in order to absorb the displacement. -LCD was obtained. The aperture ratio of the MIM-LCD manufactured by the prior art was about 28 to 37%, whereas the aperture ratio of the MIM-LCD of the present embodiment was improved to about 40 to 52%, and the effective display area was increased. It was about 1.4 times the technology.

Next, a method for manufacturing a liquid crystal display device according to a second embodiment of the present invention will be described. FIG. 4 is a view showing a state after the pixel electrode forming step, and FIG. 5 is a view showing a state after the color filter forming step. The manufacturing method of the liquid crystal display device according to the present embodiment includes the steps of:
a, a wiring forming step for forming 202b, and a pair of MIMs
A MIM element forming step of forming the elements 204a and 204b, and a pair of pixel electrodes 203a and 20
Forming a pixel electrode for forming the color filter 2b
And forming a color filter.

First, both sides are coated with a gas barrier, a hard coat or other coating treatment, and are 60 mm long and 80 mm wide.
On a resin substrate 206 made of PC (polycarbonate) having a thickness of 250 μm, a film thickness of 15 was formed by magnetron sputtering.
A Ta film of 0 nm was formed. The resin substrate 206 to be used is not particularly limited, but preferably has excellent heat resistance, light transmittance, and chemical resistance. In addition to the Ta film, A
1 film, Mo film, Si film, or an alloy material thereof may be used. Further, the film thickness is desirably in the range of about 50 to 500 nm. At the time of film formation, care must be taken so that the resin substrate 206 is not damaged by temperature, plasma, or the like. In the present embodiment, by keeping the substrate temperature during film formation at 150 ° C. or less,
Reduced damage to 6.

Next, by a series of photo-etching steps such as resist coating, pre-baking, exposure, development, post-baking, etching and resist peeling, T
A film pattern was formed. In the present embodiment, the display area is a rectangular filter having a length of 45 mm and a width of 60 mm, the number of pixels is 150 × 200 × 3 (RGB), and the area per pixel is 300 μm × 100 μm × 3 (RGB). And processed into a shape corresponding to the color AM substrate 201 using.

Generally, when color display is performed by a color filter, one pixel is divided into three regions for displaying each color of red (R), green (G) and blue (B). The shape of the pixel electrode 203 after the division is approximately the wiring 2
It becomes a rectangle extending along the longitudinal direction of 02 (vertical direction in FIG. 4). Therefore, it is necessary to secure a sufficiently large margin for the interval T2 between the wiring 202 and the pixel electrode 203, and the fabrication on the resin substrate 206 is extremely disadvantageous in terms of aperture ratio.

Therefore, when a color filter is provided on the prior art AM substrate 30 shown in FIG. 7 to perform color display, it is necessary to secure a sufficient margin and manufacture a liquid crystal display panel having a high pixel density. Then, it was extremely difficult to secure the brightness. However, by applying the present invention, it becomes possible to improve the aperture ratio and obtain a bright display screen as compared with the prior art.

In this embodiment, assuming that the expansion and contraction rate of the resin substrate 206 during the manufacturing process of the liquid crystal display device is 200 ppm, the expansion and contraction amount of the region where the pixel is formed is 45 mm in the vertical direction (the direction of FIG. 4). × 200 ppm = 9 μm and 60 mm × 200 ppm in the horizontal direction (left-right direction in FIG. 4)
= 12 μm. For this reason, the element is designed with a tolerance of 15 μm, which is larger in the vertical and horizontal directions, for the positional deviation. That is,
The interval T2 between the wiring 202 and the pixel electrode 203 is 15 μm.
It is necessary to design with a margin of m.

The interval T3 between the wirings 202 formed simultaneously in one photo process and the interval T between the pixel electrodes 203 formed simultaneously in one photo process.
Regarding No. 4, since the above large margin is not required, the interval T3 between the wirings 202 was designed to be 3 μm, and the interval T4 between the pixel electrodes 203 was designed to be 3 μm.

In this step, there is no significant difference from the ordinary process technique using a glass substrate, but the resin substrate 2 is changed depending on the temperature, chemicals, etc. during the process.
Care must be taken not to damage 06.

Wiring 20 made of patterned Ta film
2 in a 1% aqueous ammonium tartrate solution
Is anodized so that about 6
An oxide film of 0 nm was formed. The thickness of the oxide film is desirably set within a range of about 10 to 200 nm according to the device characteristics to be obtained. In addition, the solution for anodizing may be an organic acid, an inorganic acid, a salt thereof, or the like, in addition to ammonium tartrate. Further, an insulating film such as silicon nitride may be newly formed without using anodic oxidation.

Then, in order to form the upper electrode 208 by magnetron sputtering, Ti is deposited for 150 n
The film was formed to a thickness of about m. The material used for the upper electrode is not limited to Ti, and a metal such as Mo, Al, or Cr may be used. After the film formation, a pattern was formed on the upper electrode 208 by a series of photoetching steps such as resist application, prebaking, exposure, development, postbaking, etching, and resist peeling. Note that a positional shift due to a dimensional change of the resin substrate 206 may occur between the wiring 202 and the already formed wiring 202.
As described above, the design is performed with a margin of 15 μm secured. The alignment of the mask at the time of exposure was performed such that the displacement at the center of the panel was minimized. At this time, since the resin substrate 206 expanded due to the inclusion of moisture during the process, the pattern of the wiring 202 and the pattern of the mask for forming the upper electrode 208 in the pixel region on the most peripheral side of the display region were not present. Had a maximum displacement of about 80 μm in both the vertical and horizontal directions.

Next, in order to form the pixel electrode 203, the IT
An O film was formed to a thickness of 150 nm. The thickness of this ITO film is desirably about 50 to 500 nm. As a film forming means, sputtering, vapor deposition, ion plating, or the like can be used. However, a method that shows good coverage characteristics and can form a high-quality film at a low temperature is desirable. Note that the material of the pixel electrode 203 is not limited to ITO, and another transparent conductor such as tin oxide may be used. The pixel electrode 203 is made of Al or A
g as a reflective electrode using a metal such as g
It is also possible to make D. Further, after the pixel electrode 203 is formed by ITO, a reflective electrode is formed on a part of the surface of the pixel electrode 203, so that a transflective LCD can be obtained.

After the formation of the ITO film, the ITO film is formed into a pattern as shown in FIG. 4 by a series of photo-etching steps such as resist coating, pre-baking, exposure, development, post-baking, etching and resist peeling. The pixel electrode 203 was formed. This state is shown in FIG. At this time, a positional shift may occur between the wiring 202 and the upper electrode 208 already formed in the wiring forming step due to a dimensional change of the resin substrate 206.
As described above, the interval T2 between the wiring 202 and the pixel electrode 203
As a result, a design in which a margin of 15 μm was secured was performed, and the pixel electrode 203 was formed based on this design.

The alignment at the time of exposure for forming the pixel electrode 203 was performed such that the displacement at the center of the panel was minimized. At this time, since the resin substrate 206 has expanded due to moisture absorption or the like, in the pixel region on the edge side of the display region, the gap between the already formed upper electrode 208 and the pattern of the mask for forming the pixel electrode 203 is present. In addition, a maximum displacement of about 4 μm occurred in both the vertical and horizontal directions.

Here, since the adjacent pixel electrodes 203 are formed in the same pixel electrode forming step, the pixel electrodes 203
Regarding the interval T4 between them, a large margin in consideration of the dimensional change of the resin substrate during the process is not required. Therefore, the interval T4 between the pixel electrodes 203 is designed to be 3 μm.

That is, as described above, the interval T3 between the wirings 202 adjacent to each other is designed to be 3 μm, and the interval T4 between the pixel electrodes 203 adjacent to each other is designed to be 3 μm.
The AM substrate 201 of the present embodiment has a pixel electrode 203 in the region 21 as compared with the AM substrate 30 of the prior art shown in FIG.
4, the area of the effective display area (aperture ratio) is improved. In the present embodiment, the wiring 202
The interval T3 between the pixel electrodes 203 and the interval T4 between the pixel electrodes 203 are 3 μm.
m, which resulted in an aperture ratio of about 1
0-12% could be improved.

Thereafter, a liquid crystal display panel was formed by a normal process corresponding to the resin substrate, and a liquid crystal display device was obtained. The color filter 250 sequentially associates each color of R, G, and B for each column, that is, as shown in FIG.
3 is red (R), the B column pixel electrodes 203 are green (G),
The blue (B) color filter 2 is applied to the pixel electrode 203 in the C column.
Color filters of each color are arranged so that 40, 241, and 242 correspond to each other, so that color display can be performed. In the present embodiment, the steps subsequent to the pixel electrode forming step are also performed at a temperature of 150 ° C. or lower, so that the resin substrate 206
No effect was seen.

The color MIM manufactured as described above
In the LCD, due to the dimensional change of the resin substrate 206 during the manufacturing process, a total displacement of about 12 μm has occurred between the wiring 202 and the pixel electrode 203 as compared with the position at the time of design. However, in the manufacturing method of the liquid crystal display device according to the present embodiment, a color MIM-light having high brightness and high display quality is designed despite a very large margin of 15 μm to absorb this shift. LCD was obtained. While the aperture ratio of the MIM-LCD 30 manufactured by the prior art was about 40 to 53%, in the present embodiment, the aperture ratio was about 50 to 65%.
%, And the effective display area is increased from about 1.2 to
It could be 1.25 times.

[0085]

According to the present invention, the resin substrate absorbs and emits water by securing a sufficient margin between the wiring connected through the active element and the pixel electrode and performing multiple designs. Due to the factors described above, even if the dimensions change,
Problems such as direct contact between the wiring and the pixel electrode are prevented.

Further, according to the present invention, by securing a sufficient margin between the wiring connected via the active element and the pixel electrode, the resin substrate is sized due to factors such as absorption and release of moisture. Even if it changes, problems such as direct contact between the wiring and the pixel electrode are prevented.

Further, according to the present invention, it is not necessary to consider the influence of expansion and contraction of the resin substrate in the interval between the pair of wirings formed simultaneously in one photo step, so that the distance between the pair of wirings is not required. The interval T3 is designed to be 以下 or less of the maximum dimensional change amount T1. Therefore, even if a sufficiently large margin is secured between the wiring connected through the active element and the pixel electrode, the aperture ratio can be improved as compared with the liquid crystal display device of the prior art.

Further, according to the present invention, it is not necessary to consider the influence of expansion and contraction of the resin substrate in the interval T4 between the pixel electrodes of the patterns which are simultaneously formed in one photo process and are adjacent to each other. Therefore, the interval T4 between the pixel electrodes is designed to be smaller than the maximum dimensional change T1. Therefore, even if a sufficiently large margin is secured between the wiring connected through the active element and the pixel electrode, the aperture ratio can be improved as compared with the liquid crystal display device of the prior art.

Further, according to the present invention, it is not necessary to consider the influence of expansion and contraction of the resin substrate in the interval T4 between the pixel electrodes of the patterns which are simultaneously formed in one photo process and are adjacent to each other. Therefore, the interval T4 between the pixel electrodes is designed to be 以下 or less of the maximum dimensional change amount T1. Therefore, even if a sufficiently large margin is secured between the wiring connected through the active element and the pixel electrode, the aperture ratio can be improved as compared with the liquid crystal display device of the prior art.

According to the present invention, the MIM element is a TFT.
Since it can be formed by a relatively low-temperature manufacturing process as compared with the element, a resin substrate having a low heat-resistant temperature can be used instead of a glass substrate. Therefore, the dimensional change amount of the resin substrate is small, and it is not necessary to increase the distance between the wiring connected via the MIM element and the pixel electrode. Therefore, the aperture ratio is improved, and the density of pixels can be increased.

Further, according to the present invention, even when a resin substrate is used, a high-quality color liquid crystal display device having an improved aperture ratio and a high density of pixels can be obtained.

[Brief description of the drawings]

FIG. 1 is an enlarged view showing the vicinity of a pixel of an active matrix substrate 101 of an MIM element driven liquid crystal display device manufactured by a method of manufacturing a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a state after a wiring forming step.

FIG. 3 is a diagram showing a state after a MIM element forming step.

FIG. 4 is a diagram showing a state after a pixel electrode forming step.

FIG. 5 is a diagram showing a state after a color filter forming step.

FIG. 6 is a graph showing a change in expansion and contraction rate of a resin substrate in each step of a manufacturing process of an MIM-LCD.

FIG. 7 is an enlarged view of the vicinity of a pixel of an AM substrate 30 having a general structure manufactured by a method of manufacturing a liquid crystal display device according to the prior art.

[Explanation of symbols]

 102, 202 Wiring 103, 203 Pixel electrode 104, 204 MIM element 106, 206 Resin substrate 107, 207 Lower electrode 108, 208 Upper electrode 114, 214 Increased area of display area per pixel 240 Area corresponding to red color filter 241 Area corresponding to green color filter 242 Area corresponding to blue color filter 250 Color filter

Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court II (Reference) G09F 9/30 349 G02F 1/136 505 (72) Inventor Tomoko Maruyama 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Incorporated (72) Inventor Yoshinori Nakaya 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka F-term (reference) 2H048 BA02 BB02 BB14 BB15 BB43 2H090 JB03 JC07 JD18 LA04 LA15 2H091 FA02Y FA35Y FC10 FC26 FD04 FD24 GA01 GA02 GA13 LA15 2H092 JA03 JB12 JB23 JB32 JB51 KA16 KA18 KB14 MA05 MA14 MA15 MA16 MA18 MA19 MA24 MA35 MA37 MA41 PA01 PA08 QA07 5C094 AA02 AA14 AA60 BA03 BA04 BA43 CA19 EA04 EA05 EB02 ED02 HA08

Claims (7)

[Claims] 1. A pair of wirings running in the same direction adjacent to each other on a resin substrate, a pair of pixel electrodes disposed on both sides of the pair of wirings, and a pair of wirings and pixel electrodes. A method of manufacturing a liquid crystal display device, wherein a plurality of patterns including a wiring and an active element connected to a pixel electrode are formed in a matrix, and the wiring and the pixel electrode are formed in separate steps. A method for manufacturing a liquid crystal display device, wherein a distance T2 between a wiring connected by an element and a pixel electrode is designed to be larger than a maximum dimensional change T1 of a resin substrate in a manufacturing process of the liquid crystal display device. 2. The method for manufacturing a liquid crystal display device according to claim 1, wherein an interval T3 between a pair of wirings adjacent to each other and running in parallel is designed to be smaller than the maximum dimensional change T1. 3. The liquid crystal display device according to claim 2, wherein an interval T3 between a pair of wirings adjacent to each other and running in parallel is designed to be equal to or less than の of the maximum dimensional change T1. Production method. 4. The liquid crystal according to claim 1, wherein an interval T4 between pixel electrodes of each pattern adjacent to each other is designed to be smaller than the maximum dimensional change T1. A method for manufacturing a display device. 5. The manufacturing of the liquid crystal display device according to claim 4, wherein an interval T4 between pixel electrodes of each pattern adjacent to each other is designed to be equal to or less than 1/2 of the maximum dimensional change T1. Method. 6. The liquid crystal display according to claim 1, wherein the active element is a MIM element in which a metal film, an insulating film, and a metal film are stacked in this order. Device manufacturing method. 7. The method according to claim 1, further comprising the step of forming a color filter.