KR20030018475A - Method for forming spacer of liquid crystal display - Google Patents

Abstract

PURPOSE: A method for forming a spacer of a liquid crystal display is provided to minimize a period of time required for measuring the thickness of a column spacer formed in a fine size to improve productivity. CONSTITUTION: A column spacer(16) is formed in a pixel array area(11A,11B,11C,11D) of a substrate(10) using photolithography and, simultaneously, a dummy spacer(17) is formed in a region surrounding the pixel array area. The dummy spacer and the column spacer has the same thickness. The dummy spacer has a rectangular shape. The column spacer and the dummy spacer are formed on an upper substrate of a liquid crystal display. The dummy spacer is formed at the portion in close proximity to upper and lower corners of the pixel array area.

Description

Spacer formation method of liquid crystal display device {METHOD FOR FORMING SPACER OF LIQUID CRYSTAL DISPLAY}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a spacer of a liquid crystal display, and in particular, to minimize the time required to measure the thickness of a column spacer (column spacer) formed in a fine size, and to make it suitable for improving productivity of the liquid crystal display. A method of forming a spacer in an apparatus.

In general, a liquid crystal display (LCD) is bonded so that the lower plate and the upper plate face each other with a uniform separation gap, and the liquid crystal is filled in the gap between the lower plate and the upper plate.

In this case, in the lower plate, unit pixels are arranged in a matrix form on a glass substrate, and the unit pixels include a thin film transistor (TFT) and a pixel electrode.

In addition, the upper plate is patterned on a separate glass substrate with a common electrode, an RGB color filter, and a black matrix.

As described above, the liquid crystal display device applies an electric field between the pixel electrode formed on the lower plate and the common electrode formed on the upper plate to change the arrangement of liquid crystals for each unit pixel, thereby passing or blocking light to express an image composed of characters or images. Done.

Hereinafter, the manufacturing process of the liquid crystal display device will be briefly described.

First, a unit pixel including a thin film transistor, a pixel electrode, and a capacitor is formed in a matrix on a lower glass substrate.

The common electrode, the color filter, and the black matrix are patterned on the glass substrate of the upper plate.

Then, an alignment layer is formed on the lower plate and the upper plate, and then rubbing is performed. At this time, rubbing refers to a process of determining the initial alignment direction of the liquid crystal by rubbing the surface of the alignment film at a uniform pressure and speed using a cloth so that the polymer chains on the surface of the alignment film are aligned in a predetermined direction.

Then, a seal pattern is printed on the top plate. In this case, the seal pattern serves to provide a gap for injecting the liquid crystal and to prevent leakage of the injected liquid crystal.

Then, a spacer is distributed on the lower plate.

Then, the upper plate and the lower plate are bonded together. At this time, the alignment of the upper plate and the lower plate is determined by the margin given during the design process of the upper plate and the lower plate, and a precision of several μm is usually required, and when the margin is out of the margin, light is leaked out. The desired image quality characteristics of the device cannot be expected.

The bonded upper and lower plates are cut into unit panels. In this case, since the liquid crystal display device improves yield by simultaneously forming a plurality of liquid crystal panels on a large area glass substrate, the liquid crystal display device is cut into a unit panel.

In general, the cutting of the unit panel includes a scribe process of forming a cutting line on the surface of the substrate with a diamond pen having a hardness higher than that of a glass substrate, and a break process of applying a mechanical force to cut the unit panel.

Then, liquid crystal is injected into the cut unit panel, and the injection hole is sealed.

In general, in the manufacturing process of the initial liquid crystal display device, liquid crystals are injected into a plurality of liquid crystal panels and then cut into a unit panel. However, as the size of the unit panel increases, a method of cutting a unit panel and then injecting liquid crystals is used.

Since the unit panel has a gap of several μm in an area of several hundred cm 2, a vacuum injection method using a pressure difference between inside and outside of the unit panel is most commonly used to effectively inject liquid crystal.

A detailed description of the spacer dispersion during the manufacturing process of the liquid crystal display device described above is as follows.

The spacer is used to precisely and uniformly maintain the gap-gap between the upper and lower plates, and distributes polystyrene particles having a diameter of about 3 to 4 μm on the lower plate with uniform density.

However, the spacer formed by the above-described dispersion method has a large number of materials having a diameter of about 3 to 4 μm, and thus can be applied to a liquid crystal display having a high cell-gap, but having a diameter of about 2 μm. According to the difficulty of developing a material having a high molecular weight, it is difficult to manufacture a liquid crystal display device having a low cell gap.

In addition, since the spacer particles are randomly scattered on the glass substrate, a spacer may be present in the effective pixel portion, causing the spacer to shine or scattering incident light, thereby degrading the image quality of the liquid crystal display. In particular, in a large-area liquid crystal display device, due to the aggregation of scattered spacers in various places, image quality defects such as the Milky Way stain are generated.

In view of the problems described above, a method of forming a patterned spacer through photolithography has been proposed. In this method, a photoresist film is applied to a substrate, ultraviolet rays are irradiated through a predetermined mask, and then developed to selectively form dot or stripe column spacers in portions other than the effective pixel portion. In this way, since the gap-gap between the upper and lower plates can be adjusted by the thickness of the photoresist film, it is easy to control and has high precision.

Hereinafter, a process of forming a top plate of a liquid crystal display and a process of forming a column spacer on the top of the liquid crystal display will be described in detail with reference to the accompanying drawings.

First, FIG. 1 is a plan view of an upper plate of a liquid crystal display.

Referring to FIG. 1, an upper plate of a liquid crystal display includes R, G, and B color filters 3 patterned in a matrix form on a glass substrate (not shown), and the R, G, and B colors. It consists of the black matrix 2 applied to the upper surface of the glass substrate on which the filter 3 is not formed.

Although not shown in the drawings, a planarization film and a common electrode are stacked on the upper surface of the upper plate including the R, G, and B color filters 3 and the black matrix 2, and the R color filter 3 The column spacer 6 is formed on the upper surface of the common electrode adjacent to the (), and the common electrode is bonded to face the lower plate on which the thin film transistor and the pixel electrode are formed while maintaining a constant gap.

FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG. 1, and as shown therein, the upper panel of the liquid crystal display device has black matrixes 2 spaced apart from each other on the glass substrate 1 at regular intervals. R, G, and B color filters 3 extending from an upper portion of the glass substrate 1 spaced apart from the black matrix 2 to a predetermined region on the upper portion of the black matrix 2 and spaced apart from each other; And a planarization film 4 formed on the front surfaces of the G and B color filters 3 and the black matrix 2, a common electrode 5 formed on the planarization film 4, and the R color filter 3. And a column spacer 6 formed on an upper surface of the common electrode 5 adjacent thereto, and the common electrode 5 is formed by the column spacer 6 while maintaining a constant gap between the lower plate and the thin film transistor and the pixel electrode. To face each other.

The column spacer 6 shown in FIGS. 1 and 2 is formed in an area adjacent to each of the R color filters 3 to maintain a constant separation gap when the upper plate and the lower plate are bonded to each other. It may be selectively formed in an area adjacent to the G color filter 3 or every B color filter 3.

The column spacer 6 applies a photoresist film on the common electrode 5, irradiates ultraviolet rays to the photoresist film through a mask in which holes of about 13 × 13 μm are regularly spaced, and then develops the photoresist film. In this case, the actual column spacer 6 is formed in the form of a dot having a size of about 20 × 20 μm.

As described above, after the column spacer 6 is formed, the thickness inspection is performed to check whether the thickness of the column spacer 6 is uniform on the entire surface of the substrate. In this case, the thickness inspection is performed by Tencor equipment, AFM equipment, or SEM equipment. Is done through.

In the case of the AFM equipment, even an experienced operator takes about 10 minutes or more to measure the thickness of the individual column spacer 6, and in the case of the SEM equipment, a scrap of a sample is required, and compared to the measurement time. There is a problem that takes a long time.

Therefore, tenco equipment having a very short measurement time is generally used as compared to the AFM equipment and the SEM equipment, and the tenco equipment allows the provided probe to pass on the column spacer 6 to reduce the step between the substrate and the column spacer 6. How to measure.

At this time, since the size of the column spacer 6 is as small as 20 x 20 占 퐉, measurement is difficult and the time required for measurement is long, which is a factor that lowers the productivity of the liquid crystal display as a whole. In addition, as shown in an enlarged view of the column spacer 6 of FIG. 3, the column spacer 6 having a dot shape having a size of about 20 × 20 μm is thinner from the center to the edge thereof. Since it is formed in the form of a picture, if the probe of the Tenko equipment passes through the edge of the column spacer 6, not the center, an error may occur in the thickness measurement.

Accordingly, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to minimize the time required to measure the thickness of the column spacer formed in a fine size to improve the productivity of the liquid crystal display A method of forming a spacer in an apparatus is provided.

1 is a plan view of a top plate of a general liquid crystal display.

FIG. 2 is a cross-sectional view taken along line AA ′ of FIG. 1; FIG.

3 is an enlarged view of a column spacer in FIG. 1;

Figure 4 is a plan view showing a patterned dummy spacer formed on the top plate of the liquid crystal display according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view taken along the line BB ′ of FIG. 4. FIG.

FIG. 6 is an enlarged view of a patterned dummy spacer in FIG. 4; FIG.

7 is a plan view showing a patterned dummy spacer formed on a top plate of a liquid crystal display according to another embodiment of the present invention.

** Explanation of symbols for main parts of drawings **

10: glass substrate 11A to 11D: pixel array region

12: black matrix 13: R, G, B color filter

14 flattening film 15 common electrode

16: Column spacer 17: Patterned dummy spacer

The spacer forming method of the liquid crystal display device to achieve the object of the present invention as described above is to form a column spacer in the pixel array region of the substrate using photolithography and at the same time as the column spacer outside the pixel array region of the substrate And forming a patterned dummy spacer of thickness.

At this time, the patterned dummy spacer is characterized in that it is formed to have a rectangular plane of about horizontal × vertical = 20 × 1000㎛.

The substrate may be a top plate of the liquid crystal display.

The spacer forming method of the liquid crystal display according to the present invention as described above will be described in detail with reference to the accompanying drawings.

First, FIG. 4 is a plan view showing a patterned dummy spacer formed on a top plate of a liquid crystal display according to an exemplary embodiment of the present invention. As shown in FIG. 4, the top plate of the liquid crystal display may have a large area to improve yield. After the plurality of pixel array regions 11A to 11D are formed on the glass substrate 10 at the same time, they are cut into unit panels.

In the plurality of pixel array regions 11A to 11D, R, G, and B color filters 13 patterned in a matrix form, and pixel array regions in which the R, G, and B color filters 13 are not formed ( The black matrix 12 applied to each of 11A to 11D is formed, and although not shown in the drawing, the flat front surface of the upper plate including the R, G, and B color filters 13 and the black matrix 12 is flattened. A film and a common electrode are laminated.

In addition, a dot-shaped column spacer 16 having a size of about 20 × 20 μm is formed on an upper surface of the common electrode adjacent to the R color filter 13, and both side edges of the pixel array regions 11A to 11D are formed. A patterned dummy spacer 17 having a rectangular plane spaced apart from each other and having a rectangular plane of about horizontal × vertical = 20 × 1000 μm is formed to have the same thickness as that of the column spacer 16, so that the common electrode maintains a constant separation gap while having a lower plate. Are joined to face each other.

5 is a cross-sectional view taken along the line B-B 'of FIG. 4, and as shown in FIG. 5, the upper panel of the liquid crystal display is coated with a black matrix spaced apart at regular intervals in the pixel array region on the glass substrate 10. (12) and the R, G, B color filters 13 which are formed to be spaced apart from each other by extending from the upper portion of the glass substrate 10 where the black matrix 12 is spaced from the upper portion of the black matrix 12 to the predetermined region. And a planarization film 14 and a common electrode 15 stacked on the upper surfaces of the R, G, and B color filters 13 and the black matrix 12, and an upper surface of the common electrode 15 adjacent to the R color filter. And a patterned dummy spacer 17 having a rectangular plane having a width × length = 20 × 1000 μm around the pixel array region on the glass substrate 10, and the common electrode formed on the glass substrate 10. (15) by means of column spacers 16 and patterned dummy spacers 17 While maintaining the prescribed spacing gaps are attached to each other so as to face the lower plate.

In this case, the column spacer 16 and the patterned dummy spacer 17 are simultaneously formed by photolithography by applying a photoresist film on the common electrode 15, selectively irradiating ultraviolet rays using a mask, and then developing. As such, no additional processing is required to form the patterned dummy spacers 17.

In other words, a hole of approximately 13 × 13 μm is regularly spaced in the mask area corresponding to the pixel array area of the glass substrate 10, and the mask area corresponding to the outside of the pixel array area of the glass substrate 10 is formed. Holes are formed in the order of about 13 x 65 mu m.

If the photoresist film is selectively irradiated with ultraviolet rays through the mask on which the hole is formed, and then developed, the column spacer 16 having a dot shape having a size of about 20 × 20 μm is formed in the pixel array region of the glass substrate 10. Are uniformly spaced apart, and at the same time, a patterned dummy spacer 17 having a rectangular plane of about horizontal × vertical = 20 × 1000 μm is formed outside the pixel array region of the glass substrate 10.

As described above, when the patterned dummy spacer 17 having a rectangular plane of about the width × length = 20 × 1000 μm is formed outside the pixel array region of the glass substrate 10 with the same thickness as the column spacer 16. The thickness of the column spacer 16 is measured by measuring the thickness of the patterned dummy spacer 17 easily and accurately within a short time by allowing the probe provided in the Tenco equipment to pass the patterned dummy spacer 17 in the left and right directions. Can be judged.

That is, as shown in an enlarged view of the patterned dummy spacers 17 of FIG. 6, the dummy spacers 17 have a size of about horizontal × length = 20 × 1000 μm and have a long rectangular planar shape in the longitudinal direction. And the same thickness as that of the column spacer 16, so that the probe of Tenco equipment can pass through the fine column spacer 16 of about 20 x 20 占 퐉 and can be patterned easily and accurately in a faster time. The thickness of the spacer 17 can be measured, and the time and error required for the thickness measurement can be reduced even when the thickness is measured through AFM equipment or SEM equipment.

In this case, the dummy spacer 17 is spaced apart from the upper and lower edges of the pixel array regions 11A to 11D as shown in the exemplary diagram of FIG. 7 to form a rectangular plane of about horizontal × vertical = 1000 × 20 μm. It can be formed to have a probe of Tenco equipment can pass in the vertical direction.

As described above, the spacer forming method of the liquid crystal display according to the present invention comprises a patterned dummy spacer having a rectangular plane of about the width × length = 20 × 1000 μm at the same thickness as the column spacer outside the pixel array region of the glass substrate. By forming, it is possible to determine the thickness of the column spacer by measuring the thickness of the patterned dummy spacer easily and accurately within a short time.

Therefore, compared to measuring the thickness of the column spacer through the Tenko equipment, it is possible to measure the thickness of the dummy spacer easily and accurately patterned in a faster time, and also when measuring the thickness through the AFM equipment or SEM equipment Since the time and the error required for the thickness measurement can be reduced, the productivity and yield of the liquid crystal display can be improved.

Meanwhile, in the exemplary embodiment of the present invention, an example in which the column spacer and the patterned dummy spacer are formed on the upper plate of the liquid crystal display has been described. However, those skilled in the art to which the present invention pertains will understand the technical idea of the present invention. The technical spirit of the present invention may be changed and modified without departing from the scope of the present invention and may be easily applied to the lower plate of the liquid crystal display.

Therefore, the technical scope of the present invention will be defined by the claims rather than the contents described in the detailed description of the specification.

Claims (6)

Photolithography is used to form column spacers in the pixel array region of the substrate, and at the same time forming a patterned dummy spacer having the same thickness as the column spacers outside the pixel array region of the substrate. Spacer formation method of the. The method of claim 1, wherein the patterned dummy spacer is formed to have a rectangular plane spaced apart from both side edge portions of the pixel array region of the substrate. The method of claim 1, wherein the patterned dummy spacers are formed to have a rectangular plane spaced apart from upper and lower edge portions of the pixel array region of the substrate. 3. The method of claim 2, wherein a rectangular plane of the patterned dummy spacer is about horizontal x vertical = 20 x 1000 mu m. The method of claim 3, wherein the rectangular plane of the patterned dummy spacer is about horizontal × vertical = 1000 × 20 μm. The method of claim 1, wherein the substrate is a top plate of the liquid crystal display.