CN1979344A - Exposure method using exposure mask - Google Patents

Abstract

The present invention provides an exposure method using an exposure mask. A partition exposure method using a mask comprising: providing a substrate having a thin film; forming a photoresist layer on the thin film, wherein the photoresist layer is divided into at least a first irradiation area and a second irradiation area; exposing means to irradiate first light onto the first irradiated area through the mask; disposing the mask in the second irradiated area; and irradiating second light through the mask by the exposing means onto the second irradiated area, wherein the intensity of the second light exposing the left side of the second irradiated area is substantially the same as the intensity of the first light exposing the right side of the first irradiated area.

Description

Exposure method using exposure mask

This application is a divisional application of the original patent application number 200410103651.X (application date: December 30, 2004, invention name: exposure mask and exposure method using the exposure mask).

technical field

The present invention relates to a liquid crystal display panel, and more particularly, to an exposure mask for compensating for light intensity deviation of an exposure device (exposer).

Background technique

In general, a liquid crystal display device displays images by controlling light transmittance of dielectrically anisotropic liquid crystals using an electric field. The liquid crystal display device includes: a liquid crystal display panel having a plurality of liquid crystal cells arranged in a matrix for displaying images; and a driving circuit for driving the liquid crystal display panel. Active matrix type liquid crystal displays, which independently drive liquid crystal cells using thin film transistors, are widely used in display devices of televisions and personal computers.

The liquid crystal display panel includes: a thin film transistor substrate and a color filter array substrate facing each other; a liquid crystal disposed between the two substrates; and a spacer for maintaining a cell gap between the substrates.

The thin film transistor substrate includes: a gate line and a data line; a thin film transistor formed near the intersection of the gate line and the data line; a pixel electrode connected to the thin film transistor at each liquid crystal unit; and formed on the thin film transistor substrate alignment film.

The color filter substrate includes: a plurality of color filters corresponding to a plurality of liquid crystal cells; a black matrix (black matrix) for reflecting external light between the color filters; a voltage common electrode; and an alignment film formed on the color filter substrate.

A thin film transistor substrate and a color filter substrate are separately bonded together, and then a liquid crystal is provided and sealed between the two substrates to form a liquid crystal display panel.

Multiple mask processes are required to form the patterns of the thin film transistor substrate and the color filter substrate. Each mask process includes film deposition process, cleaning process, photolithography process, etching process, photoresist stripping process and inspection process. When the substrate is larger than the effective area of the exposure apparatus used in the photolithography process, a stitch (section) exposure method is employed. The stitch exposure method involves segmental exposure of the substrate.

Figure 1 shows a seam exposure method according to the prior art. Referring to FIG. 1 , a substrate 20 has a thin film for patterning (a metal layer, an insulating layer, a semiconductor layer, etc., not shown) and a photoresist formed on the thin film. The photoresist is exposed through the mask 10, and a photoresist pattern is formed corresponding to the pattern of the mask 10 during the exposure process. Since the substrate 20 is larger than the mask 10, the exposure process is repeated to form the photoresist pattern shown in FIG. 1 while the mask 10 is removed. A unit in which one exposure process is performed using a mask is called a shot, and an exposed area of the substrate corresponding to one shot is called a shot area. For example, as shown in FIG. 1, the photoresist pattern on the substrate 20 has 4 shot regions A to D. Referring to FIG. In other words, the photoresist patterns of the respective shot regions A to D are sequentially exposed while removing the mask 10 .

Each shot area is exposed by an exposure device that scans along the vertical direction of the substrate 20 . Generally, the light intensity (luminous intensity) of the exposure device is relatively high in the middle portion of the irradiation area and lower in the left and/or right sides of the irradiation area. An exemplary relationship between the light intensity of the exposure device and the position of the irradiation area is shown in FIG. 1 . Furthermore, it is also shown in FIG. 1 that the light intensity decreases at different rates between the left and right sides of the illuminated area. The difference in light intensity between the left and right sides of the irradiated area causes patterns formed on the left side and patterns formed on the right side to have different critical dimensions CD, ie, pattern thicknesses and positional deviations. A stitch stain may be generated in a liquid crystal display panel because there is a CD deviation between patterns formed at the boundary between adjacent irradiated regions.

For example, the pattern formed in the middle part of the shot area has a CD of P, while the pattern formed on the left side of each shot area A to D has a CD of P+2a due to the difference in exposure, and the pattern formed on the right side thereof CD with P+a. In general, the right light intensity, which is stronger than the left light, results in patterns formed on the right side of the illuminated area having a larger CD than patterns formed on the left side of the illuminated area. Therefore, a boundary area between adjacent shot areas A to D is formed by the left pattern of the CD with P+2a and the right pattern of the CD with P+a, resulting in CD deviation between the shot areas. In other words, the left and right patterns having a CD deviation ratio of 2a:a are adjacent to each other in the boundary area of the irradiation areas A to D. FIG. Stitching defects are generated in the liquid crystal display panel due to CD deviation in the boundary area between the irradiated areas A to D.

To solve this problem, a method has been proposed in which a plurality of patterns are partitionedly formed on both sides of a mask and overlapped to be combined in adjacent shot regions, thereby reducing CD deviation. However, there is a CD deviation between patterns formed on the left and right sides of the mask because of the difference in light intensity between the left and right sides of the exposure device, and thus there is a problem of stitching defects.

Contents of the invention

Accordingly, the present invention is directed to an exposure mask and an exposure method using the same that substantially obviate one or more of the problems due to limitations and disadvantages of the related art.

An advantage of the present invention is to provide an exposure mask that compensates for deviations in luminous intensity of an exposure device, thereby preventing stitching defects in liquid crystal display panels.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a mask for an exposure apparatus having left and right light intensity deviations, comprising: a substrate; a first mask located in the middle of the substrate; pattern; and a second pattern and a third pattern respectively positioned on the left and right sides of the first pattern, wherein the amounts of the second pattern and the third pattern are different from each other, so as to compensate for the left-right light intensity deviation of the exposure device .

In another aspect of the present invention, a partition exposure method using a mask having a non-overlapping portion and a left overlapping portion and a right overlapping portion, wherein the pattern amount at the left overlapping portion and the right overlapping portion is the same as the pattern amount at the non-overlapping portion Differently, the method includes: providing a substrate having a thin film; forming a photoresist layer on the thin film; disposing a mask on a first irradiated area of the photoresist layer; irradiating light to the first irradiated area through the mask above; placing the mask in a second shot region of the photoresist layer, wherein the second shot region partially overlaps the first shot region such that the right overlapping portion of the mask is identical to a portion of the first shot region Correspondingly, the part of the first irradiated area corresponds to the left overlapping portion of the mask; and light is irradiated on the second irradiated area through the mask, and wherein the pattern amounts of the left overlapping portion and the right overlapping portion are different from each other, so that Compensate for left and right exposure intensity deviation.

In another aspect of the present invention, a method of partition exposure using a mask includes: providing a substrate having a thin film; forming a photoresist layer on the thin film, wherein the photoresist layer is divided into at least first and second irradiating the area; irradiating the first light to the first irradiating area through the mask by the exposure device; setting the mask in the second irradiating area; and irradiating the second light to the second irradiated area through the mask by the exposure device An area where the intensity of the second light exposing the left side of the second irradiation area is substantially the same as the intensity of the first light exposing the right side of the first irradiation area.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

Description of drawings

The accompanying drawings illustrate embodiments of the invention and together with the description serve to explain the principles of the invention, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification.

In the attached picture:

Figure 1 shows a seam exposure method according to the prior art;

FIG. 2 shows an exposure mask according to a first embodiment of the present invention;

FIG. 3 shows a seam exposure method using the exposure mask shown in FIG. 2;

FIG. 4 shows a seam exposure method according to a second embodiment of the present invention; and

FIG. 5 shows a seam exposure method according to a third embodiment of the present invention.

Detailed ways

Reference will now be made in detail to embodiments of the invention, examples of which are illustrated in the accompanying drawings.

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 2 to 5 . Fig. 2 shows a mask 30 according to a first embodiment of the invention. As shown in Figure 2, the mask 30 is divided into three parts: a non-overlapping part 32, wherein a pattern with a predetermined CD is formed; The direction of the edge is reduced. The amount of pattern at the left overlapping portion 34 and the right overlapping portion 36 can be controlled by, for example, adjusting the area, size, thickness, or transmittance of the pattern, and the amount of pattern is related to CD. The left overlapping portion 34 and the right overlapping portion 36 of the mask 30 correspond to areas where adjacent illuminated areas overlap each other. Furthermore, to compensate for CD deviation due to the difference in light intensity between the left and right sides of the exposure apparatus, the pattern amount of the left overlapping portion 34 is reduced at a different rate than that of the right overlapping portion 36 .

Generally, the light intensity (luminous intensity) on the right side of the exposure device is greater than the light intensity on the left side of the exposure device. Therefore, to compensate for this, the pattern at the left overlapping portion 34 of the mask 30 is formed to have a larger CD than the pattern at the right overlapping portion 36 in accordance with the present invention. In other words, the patterns formed at the left overlapping portion 34 and the right overlapping portion 36 of the mask 30 compensate for the light intensity difference between the left and right sides of the exposure device, which means that the mask 30 is formed to have the same The difference in light intensity of the exposure device is opposite to the CD deviation.

For example, when the pattern formed at the non-overlapping portion 32 of the mask 30 has a CD of P, and the patterns formed at the left overlapping portion 34 and the right overlapping portion 36 respectively have a CD of P-a and a CD of P-2a (where the pattern When the amount decreases from the non-overlapping portion 32 in the direction of the horizontal edge of the mask 30), the relationship between the exposure deviation of the exposure apparatus and the CD deviation of the mask 30 can be defined as follows. The exposure deviation of the left and right sides of the exposure device is (P+2a):(P+a)=2a:a. The CD deviation of the left overlapping portion 34 and the right overlapping portion 36 of the mask 30 may be (P-a):(P-2a), (P):(P+2a) or (P+2a):(P+a), To compensate for the exposure deviation of the exposure device. Due to this CD deviation in the mask 30 , the gradient of the pattern volume at the left overlapping portion 34 and the right overlapping portion 36 is made symmetrical with respect to the non-overlapping portion 32 .

As shown in FIG. 3, when the mask 30 is employed in the stitch (or partition) exposure method, the mask 30 is sequentially exposed to form irradiation regions A to D. Referring to FIG. When exposing the shot area A, the overlapping area 44 is exposed through the right overlapping portion 36 of the mask 30 . When exposing the second shot area B, the overlapping area 44 is exposed through the left overlapping portion 34 of the mask 30 . Therefore, the pattern formed at the overlapping region 44 has substantially the same CD as the pattern formed at the non-overlapping region 42 .

In addition, in the overlapping area 44 of the respective irradiation areas A to D, the difference in light intensity between the left and right sides of the exposure device is compensated by the CD deviation in the left overlapping portion 34 and the right overlapping portion 36 of the mask 30, by This prevents CD deviation between irradiated areas. Accordingly, stitching defects in the liquid crystal display panel due to CD deviation in the overlapping region 44 of the irradiated regions A to D can be reduced.

FIG. 4 shows a seam exposure method according to a second embodiment of the present invention. The substrate 120 has a thin film (metal layer, insulating film, semiconductor layer, etc., not shown) and a photoresist formed on the thin film for patterning. The photoresist on the substrate 120 is divided into four irradiation regions A to D, and exposed by using an exposure mask such as the mask 10 shown in FIG. 1 . The exposures of the respective shot areas A to D are individually controlled to compensate for exposure deviations at the boundary areas of the shot areas A to D.

For example, as shown in FIG. 4, when the first shot area A is exposed by an exposure device having a left and right exposure deviation of P+2a:P+a, the exposure device is controlled so that for the second shot area B There is a left-right exposure deviation of P+a:P-a. For this reason, the exposure speed (ie light scanning speed) or the absolute luminous intensity of the exposure device can be controlled. Therefore, the deviation between the right exposure of the first shot area A and the left exposure of the second shot area B can be reduced. In addition, when exposing the third shot region C, the exposure apparatus is controlled in the same manner as above so as to have a left-right deviation of P-a:P-3a. In addition, when exposing the fourth shot region D, the exposure device is controlled so as to have a left-right deviation of P-3a:P-5a.

In this way, in the seam exposure method according to the second embodiment of the present invention, in the boundary area of the first to fourth shot areas A to D, the left exposure deviation of the next shot area becomes the same as that of the previous shot area. The right exposure bias of is the same. Therefore, it is possible to reduce CD deviation caused by exposure deviation in the boundary area of the first to fourth irradiation areas A to D, thereby minimizing or preventing stitching defects in the liquid crystal display panel from being generated. .

FIG. 5 shows a seam exposure method according to a third embodiment of the present invention. Referring to FIG. 5, the mask 230 includes: a non-overlapping portion 232, wherein a pattern having a predetermined CD is formed; The direction of the horizontal edge of the die 230 decreases. The left overlapping portion 234 and the right overlapping portion 236 of the mask 230 correspond to regions that overlap adjacent to each other.

The respective shot regions A to D in FIG. 5 are sequentially exposed through the mask 230 . The overlapping region 244 of the first to fourth irradiation regions A to D is exposed through the right overlapping portion 236 and is also exposed through the left overlapping portion 234 of the mask 230 in the next irradiation process. Accordingly, the pattern formed at the overlapping region 244 has substantially the same CD as the pattern formed at the non-overlapping region 242 .

In addition, in the overlapping area 244 of the first to fourth shot areas A to D, for each shot area A to D, the exposure device is controlled so that the left exposure deviation of the next shot is the same as the right exposure deviation of the previous shot. same. Accordingly, CD deviation due to exposure deviation in the overlapping region 244 of the first to fourth irradiation regions A to D can be reduced, thereby minimizing stitching defects in the liquid crystal display panel.

As described above, the patterns formed at the left and right overlapping portions of the mask according to the present invention compensate for the difference in light intensity between the left and right sides of the exposure device, which means that the mask is formed to have CD deviations with opposite intensity differences, thereby reducing or preventing seam defects in LCD panels.

In addition, according to the stitching exposure method of the present invention, by controlling the light intensity distribution of the exposure device, in the boundary area between the irradiation areas, the left exposure deviation of the next irradiation area becomes the same as the right exposure deviation of the previous irradiation area . Therefore, it is possible to reduce CD deviation due to exposure deviation in the boundary area between adjacent irradiated areas, thereby reducing or preventing stitching defects in the liquid crystal display panel.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention that come within the scope of the appended claims and their equivalents.

This application claims the benefit of Korean Patent Application No. P2003-99807 filed in Korea on Dec. 30, 2003 and Korean Patent Application No. P2003-99808 filed in Korea on Dec. 30, 2003, which are hereby incorporated by reference its entire contents.

Claims (3)

1. A partition exposure method using a mask, the method comprising: providing a substrate with a thin film; forming a photoresist layer on the thin film, wherein the photoresist layer is divided into at least a first irradiated area and a second irradiated area; irradiating first light onto the first irradiation area through the mask by an exposure device; disposing the mask in the second shot region; and The second light is irradiated onto the second irradiated area by the exposure device through the mask, wherein the intensity of the second light exposed to the left side of the second irradiated area is the same as that of the first irradiated area. The intensity of the first light for exposure on the right is substantially the same. 2. The method according to claim 1, wherein the intensity of the second light is adjusted by controlling a scanning speed or a light intensity of the exposure device. 3. The method of claim 1, wherein the second illuminated area partially overlaps the first illuminated area.

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