Gray mask and manufacturing method thereof

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a gray tone mask having a high-accuracy pattern of a gray tone portion. ŽSOLUTION: The method for manufacturing a gray tone mask includes a drawing step for drawing patterns in a photosensitive material layer formed on a mask blank, having a light shielding film on a transparent substrate. The drawing step is carried out by having a mask blank irradiated with an energy beam under almost identical lithographic conditions for repeated patterns, corresponding to the pixel pattern of a substrate for a display, as well as, by determining the drawing position so as to obtain the optimum drawing conditions in the gray tone region of the repeated pattern. The gray tone portion is an area where a light-shielding pattern of the resolution limit or smaller than the limit of an aligner to be used for exposure, by using the gray tone mask is formed. Ž

Description

technical field [0001] This invention relates to the gray tone mask used for manufacture of a liquid crystal display device (Liquid Crystal Display: hereinafter referred to as LCD) etc., and its manufacturing method. Background technique [0002] Thin Film Transistor Liquid Crystal Displays (Thin Film Transistor Liquid Crystal Displays: hereinafter referred to as TFT-LCDs) are rapidly being commercialized due to their advantages of easier thinning and lower power consumption than CRTs (cathode ray tubes). TFT-LCD has a general structure in which a TFT substrate and a color filter are laminated, and a liquid crystal phase is interposed between the two. The structure of the TFT substrate is that TFTs are arranged on each pixel arranged in a matrix. The color filter The light sheet is arranged with red, green and blue pixel patterns corresponding to each pixel. Regarding TFT-LCD, there are many manufacturing steps, and 5 to 6 photomasks are used to manufacture only the TFT sub...

AI Technical Summary

Problems solved by technology

[0019] However, although theoretically a pattern with a predetermined resolution line width should be formed at a predetermined position as described above, according to research by the present inventors, it has been found that in practice, it may not be possible to form a pattern due to variations in the beam intensity of each energy level. expected pattern

For example, as described above, when resolving a pattern with a resolution linewidth of 1 μm, such as a combination of energy level 15 and energy level 5, when different energy levels are combined at both ends of the pattern, the laser output, etc. deviation, etc., resulting in a deviation in the size of the pattern, and the desired line width cannot be distinguished

[0020] That is, what Fig. 7 shows is the pattern of the gray-tone part in the described gray-tone mask (in the figure, the up-down direction is the traveling direction (X direction) of the beam, and the left-right direction is the scanning direction (Y direction) of the beam), According to the study of the present inventors, it was found that, for example, when the light-transmitting portion 21a between the light-shielding patterns 22a of the gray-tone portion is to have a line width of 1 μm, as shown in the drawing data structure of FIG. Level 15 and energy level 5 are drawn, theoretically, a pattern with a resolution line width of 1 μm will be formed at a predetermined position as shown in Figure 7(2), but in practice, completely different combinations of In the case of the energy level, due to the deviation of the laser output, etc., as shown in Fig. 7 (3), the size of the pattern will vary, and the pattern with the desired line width cannot be formed.

In addition, in this case, even if the line width of the drawn pattern is not ideal, it has been proposed that the line width of the drawn pattern can be adjusted through the subsequent etching process. The degree of deviation of the laser output at both ends of the laser (deviation from the ideal situation) is different, so that when the etching process needs to be adjusted uniformly, the deviation of the pattern will instead increase, making it difficult to adjust the pattern through the etching process

[0021] Such a size deviation of the pattern directly leads to a deviation of the light transmittance of the gray tone part

Therefore, in the case of manufacturing a TFT substrate using a gray-tone mask having the above-mentioned gray-tone portion, defects will be generated on the channel portion corresponding to the gray-tone portion, resulting in a short circuit between the source and the drain, and damage to the TFT. speaking is fatal

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