JP2007121688A - Method for manufacturing liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a liquid crystal display device in which the accuracy of substrate alignment can be relatively easily enhanced by improving an alignment mark. <P>SOLUTION: The method for manufacturing the liquid crystal display device comprises an array step of forming wiring and pixel electrodes on counter substrates, a cell step of producing a liquid crystal panel by filling the liquid crystal between the substrates, and a module step of mounting electronic circuits between the substrates for display; includes a step of aligning the central position of the alignment mark 32a by using an auxiliary shape 32m formed at the end of the alignment mark 32a in performing the alignment by using the alignment mark 32a formed on the substrate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a liquid crystal display device using alignment marks.

In a general manufacturing process of a liquid crystal display device, individual liquid crystal panels are divided by a scribe / break method from a large panel in which a plurality of liquid crystal panels are arranged. Here, in order to accurately align the scribe line, a so-called alignment mark is usually formed on the substrate. The alignment mark is read by a camera and its position is recognized by an image recognition technique. For this reason, a complicated alignment mark may misrecognize the shape of a wiring or a switching element formed on the substrate as an alignment mark, and is difficult to read by a machine. Cross-shaped alignment marks as described are used relatively often.

This alignment mark is also used for alignment when bonding substrates together, alignment when attaching a flexible printed wiring board to the substrates, and the like.
JP-A-8-184895

As described above, alignment marks are used in various applications in the manufacture of liquid crystal display devices.

And, for example, in the scribing process, the alignment mark is first read by the camera and displayed on the screen, and the alignment mark center is aligned with the alignment crosshair displayed on the screen to determine the alignment mark center. Is registered in the device.
Thereafter, the alignment mark registered by the apparatus is recognized by a method of automatically searching for a shape similar to the registered alignment mark by image recognition technology.

FIG. 8 shows a screen 33 that displays an image captured by the camera. Lines are displayed vertically and horizontally on the screen 33 to form a cross hair 34 for alignment. FIG. 9 shows a cross-shaped alignment mark 40. The width of one end of the alignment mark 40 is about 0.2 to 0.4 mm.

Since the center alignment of the first alignment mark 40 is usually performed manually by visual inspection, an error in visual alignment is likely to occur (the state shown by the broken line in FIG. 10. The alignment mark shown by the solid line) 40 is a state where the center of the arament mark 40 is accurately positioned.)

If the alignment mark is registered with a deviation from the center for the first time, the alignment mark will continue to be automatically recognized with the error, so the entire board will be affected by the error, and the cutting position will also shift. End up. In other words, it is cut by an error. Then, the shift also affects each panel after cutting, for example, a connection shift of the flexible substrate and a display area shift of the panel. Therefore, the normally acceptable error must be kept very small.

Accordingly, an object of the present invention is to provide a method of manufacturing a liquid crystal display device that can improve the alignment accuracy of a substrate relatively easily by improving the alignment mark.

In order to achieve the above object, the present invention provides an array process for forming wirings and pixel electrodes on a substrate to be opposed, a cell process for producing a liquid crystal panel by encapsulating liquid crystal between the substrates,
In a manufacturing method of a liquid crystal display device having a module process in which an electronic circuit is attached to the liquid crystal panel for display, when alignment is performed using an alignment mark formed on the substrate, the alignment mark A method of manufacturing a liquid crystal display device comprising a step of aligning the center position of the alignment mark using an auxiliary shape formed at an end.

Thereby, the center position of the first alignment mark 40 can be accurately aligned, and the alignment accuracy can be further improved.

In addition, when aligning using the alignment mark formed on the substrate,
First, using the auxiliary shape formed at the end of the alignment mark, the center position of the alignment mark is aligned, and then the alignment mark is recognized in a shape that does not include the auxiliary shape. To do.

Thereby, the alignment accuracy can be further improved, and the alignment mark can be easily and quickly found.

The alignment mark is a cross-shaped alignment mark, and the auxiliary shape is a triangular shape protruding from an end of the cross-shaped alignment mark.

According to the present invention, by using an alignment mark having an auxiliary shape, alignment accuracy can be improved when alignment is performed using the alignment mark in various processes.

FIG. 1 is a cross-sectional view of a predetermined portion of a TFT active matrix type color liquid crystal panel 10. 11 and 12 are array substrates and CF substrates made of alkali-free glass or the like.
Is a polarizing plate attached to the outside of each of the substrates 11 and 12.

15 is a wiring made of a metal thin film, 16 is a drain electrode connecting the wiring 15 and TFT (not shown), 17 is an insulating film made of silicon nitride or the like formed on the wiring 15 or the array substrate 11, Reference numeral 18 denotes a pixel electrode made of a transparent conductive film for each pixel dot connected to the drain electrode 16 through a connection hole of the insulating film 17. The exposed portion of the wiring 15 that is not covered with the insulating film 17 serves as a terminal for connecting the electronic circuit of the drive system.
1 terminal portion 11a.

Reference numeral 19 denotes a color filter (CF) attached to the inside of the CF substrate 12 for each pixel dot.
Reference numeral 20 denotes a black matrix for shielding a non-display portion, and 21 denotes an alignment film applied on the pixel electrode 18 and an opposing common electrode 23 described later. Note that chrome or resin can be used as the material of the black matrix 20.

Reference numeral 22 denotes a counter common electrode made of a transparent conductive film formed on the color filter 19 and the black matrix 20. A sealing material 23 is formed over substantially the entire circumference of the CF substrate 12 and adheres the CF substrate 12 and the insulating film 17. The portion surrounded by the sealing material 23 is filled with the liquid crystal layer 24.

Although a TFT active matrix color liquid crystal panel has been described as the liquid crystal panel 10, the present invention is not limited to this, and a liquid crystal display device can be manufactured using either a passive color liquid crystal panel or a monochrome liquid crystal panel. The present invention is applicable as long as the process includes a process of aligning with alignment marks.

Next, a manufacturing process of the liquid crystal display device including the liquid crystal panel 10 will be described. There are roughly three processes: an array process, a cell process, and a module process. In the array process, the array substrate 11 is processed to form a wiring 15, a drain electrode 16, an insulating film 17, a pixel electrode 18, and a TF.
This is an array substrate process for forming T and the like. As a substrate, a mother substrate on which a plurality of liquid crystal panels are arranged is used. The array process mentioned here is not limited to the process of forming TFTs and various wirings on a glass substrate, but a substrate constituting a passive liquid crystal panel such as an STN liquid crystal panel is manufactured. It also includes a process. That is, in the substrate constituting the liquid crystal panel, this is a step of forming pixel electrodes and wirings on the substrate.

In the next cell process, after the surface treatment is performed on the previously formed array substrate and the CF substrate opposed thereto, that is, the CF substrate 12, the two substrates are bonded together and assembled, and a gap (gap) between the two substrates is assembled. ) And injecting liquid crystal into the liquid crystal panel, and cutting the liquid crystal panel from the mother substrate.

The last module process is the process of attaching the electronic circuit of the drive system so that the array / CF substrate can be electrically controlled, and the process of attaching the electronic components and materials such as the backlight as the light source But there is.

Below, the alignment using the typical alignment mark in said manufacturing process is demonstrated. FIG. 2 is a plan view showing a state in which a large mother board is bonded. In the case of making a plurality of small liquid crystal panels using such a large mother substrate, the cutting process and the like are very many. Therefore, by applying the present invention, more accurate alignment can be easily performed. Therefore, it can be said that the present invention is very suitable. Note that the above-described pixel electrode, common electrode, and the like are formed for each panel area on the opposing surface side of the opposing mother substrate.

In FIG. 2, the alignment mark 3 is placed on the end material 31 that is a scraping white at the four corners of the mother substrate 30.
2 is formed. The alignment mark 32 is formed on either the array substrate 11 side or the CF substrate side. When forming on the array substrate 11 side, it can be formed without increasing the number of steps by forming the wiring 15 and the like with the same material at the same time. On the other hand, when it is formed on the CF substrate 12 side, it can be formed without increasing the number of steps by forming the black matrix 20 and the same material at the same time.

The alignment mark 32 is used for positioning when the mother substrate 30 is scribed. Therefore, in order to recognize this alignment mark 32, the alignment mark is first read by the camera and displayed on the screen. Next, align the center of the alignment mark with the alignment crosshair displayed on the screen. At this time, an alignment mark 32 to be described later.
The center of the alignment mark can be accurately aligned by visual observation by using the auxiliary shape formed in the above.

After aligning the center of the alignment mark, the zoom is performed until the auxiliary shape disappears from the screen, and the alignment mark in that state is registered in the apparatus. After that, as in a known method, an alignment mark is recognized by finding a similar shape on the substrate by image recognition technology, and the scribe position at the time of scribing is based on the recognized alignment mark. Is determined. In the alignment of one mother substrate, this operation is performed for three or more alignment marks 32, so that accurate alignment can be performed. Therefore, although only four alignment marks 32 are shown in FIG. 2, the number is not limited to four, and more alignment marks 32 may be used.

Next, another alignment using alignment marks will be described. FIG. 3 is a plan view of the liquid crystal panel 10 after being separated from the mother substrate 30. Alignment marks 32 are formed at two corners of the terminal portion 11a. If the alignment mark 32 is formed in this place, it can be used for positioning for attaching a flexible printed wiring board (not shown) to the terminal portion 11a in addition to being used for positioning when scribing. At this time, the alignment mark 32 is first set by the camera in the same manner as described above.
Is displayed on the screen. The center of the alignment mark 32 is aligned using the auxiliary shape formed on the alignment mark 32. Then, the alignment mark 32 is registered in a shape that does not include the auxiliary shape, and alignment is performed by recognizing the alignment mark 32.

Here, a specific example of the shape of the alignment mark is shown. First, the alignment mark 32 of FIG.
“a” is a cross shape, and triangular protrusions are formed at the upper, lower, left and right ends of the cross as an auxiliary shape 32 m. The width of one end of the alignment mark 32a is 0.2 to 0.4 mm, and the width of the auxiliary shape 32m is 0.05 mm or less.

In this way, the triangular auxiliary shape 32m protrudes outward from each end of the cross.
If the upper and lower vertices and the left and right vertices are connected, the center of the alignment mark 32a can be accurately aligned even by visual observation. If the alignment mark 32a that includes the auxiliary shape 32m is used for automatic recognition of the alignment mark, the auxiliary shape 32m increases, so that the complexity of the alignment mark increases and image recognition takes time. However, since the alignment mark 32a is originally a cross shape, the auxiliary shape 32
Even if the alignment mark 32a is registered in a shape that does not include m, the alignment mark can be automatically recognized in a short time because it is a simple shape.

Another specific example of the shape of the alignment mark is shown in FIG. The alignment mark 32b in FIG. 5 differs from the alignment mark 32a in FIG. 4 in that an auxiliary shape 32n protrudes inwardly from each end of the cross relative to the cross-shaped alignment mark 32b. That is, the auxiliary shape 32n is formed with a triangular cutout at each of the upper, lower, left and right ends of the cross. FIG.
Compared with the alignment mark 32a of FIG. 4, the alignment mark 32b shown in FIG. 4 is a device closer to the center of the mark when the alignment mark is registered with a shape that does not include the auxiliary shape after the alignment mark is centered. You must register with. However, since the alignment mark itself does not become large, when the mark is provided in a place where there is little extra space in the vicinity of the terminal portion 11a, such as when used to align the flexible printed wiring board to the terminal portion 11a described above. It will be advantageous.

The alignment mark is not particularly limited as long as it has a shape and size that can be easily recognized by the camera. However, a cross-shaped alignment mark that has been used well in the past is suitable. Further, the auxiliary shape is not particularly limited as long as it is a shape and size that can be aligned with high accuracy in visual alignment.

FIG. 6 is a diagram showing a screen 33 on which the alignment mark 32a read by the camera is displayed. A crosshair 34 for alignment is displayed on the screen 33, and an alignment mark 32a is displayed so as to overlap the crosshair 34.

At the time of alignment, as shown in FIG. 6, the crosshair 34 and the auxiliary shape 32m are adjusted so as to overlap each other. As a result, the center of the crosshair 34 and the center of the alignment mark 32a can be accurately aligned. Similarly, in the case of the alignment mark 32b, the crosshair 34 and the auxiliary shape 3
By adjusting so that 2n overlaps, the center of the crosshair 34 and the alignment mark 32b
The center of the can be accurately aligned. At this time, the width of the auxiliary shape is approximately 0.05 mm.
By making the following, the alignment error can be within an allowable range.

FIG. 7 shows a state in which the alignment mark 32a is displayed in a shape not including the auxiliary shape 32m after the alignment mark 32a is centered using the auxiliary shape 32m. Thus, since the alignment mark 32a is recognized with a simple shape that does not include the auxiliary shape 32m, the alignment mark can be found in a very short time even when the alignment mark is automatically recognized by the apparatus.

As described above, when the alignment marks 32a and 32b having auxiliary shapes are used, the alignment accuracy can be easily improved.

The manufacturing method of the liquid crystal display device of the present invention can be applied to a manufacturing method using a multi-sided mother substrate. Further, the liquid crystal display device of the present invention can be used for a liquid crystal panel having an alignment mark in a terminal portion.

It is sectional drawing of the predetermined part of the TFT active matrix type color liquid crystal panel of this invention. It is a top view of the mother board of the present invention. It is a top view of the liquid crystal panel of this invention. It is a figure which shows the example of the shape of the alignment mark of this invention. It is a figure which shows the example of the shape of the alignment mark of this invention. It is a figure which shows the screen which displayed the alignment mark read with the camera of this invention. It is a figure which shows the screen which read and displayed a part of alignment mark of this invention with the camera. It is a figure which shows the screen which displays the image image | photographed with the conventional camera. It is a figure which shows the example of the shape of the conventional alignment mark. It is a figure which shows the screen which displayed the alignment mark read with the conventional camera.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Liquid crystal panel 11 Array board | substrate 11a Terminal part 12 CF board | substrate 17 Insulating film 20 Black matrix 32a, 32b Alignment mark 32m, 32n Auxiliary shape

Claims (3)

An array process for forming wiring and pixel electrodes on the substrate to be opposed;
A cell process for producing a liquid crystal panel by enclosing a liquid crystal between the substrates;
In a manufacturing method of a liquid crystal display device having a module process for mounting and displaying an electronic circuit on the liquid crystal panel,
When aligning using the alignment mark formed on the substrate,
A method for manufacturing a liquid crystal display device, comprising the step of aligning the center position of the alignment mark using an auxiliary shape formed at an end of the alignment mark. When aligning using the alignment mark formed on the substrate,
First, using the auxiliary shape formed at the end of the alignment mark, align the center position of the alignment mark,
The method for manufacturing a liquid crystal display device according to claim 1, wherein the alignment mark is recognized in a shape not including the auxiliary shape. The alignment mark is a cross-shaped alignment mark,
3. The method of manufacturing a liquid crystal display device according to claim 1, wherein the auxiliary shape is a triangular shape protruding from an end portion of the cross-shaped alignment mark.

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