JP2741114B2 - Alignment method of color liquid crystal substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention relates to a method of aligning color liquid crystal board and, more particularly relates <br/> the mask plate for the three primary colors in a method of aligning to projection exposure to the liquid crystal substrate.

[0002]

2. Description of the Related Art Recently, a liquid crystal panel for color has been developed by a liquid crystal technology which has been rapidly developed. To manufacture this liquid crystal panel, each pattern is transferred by projection exposure to a liquid crystal substrate through a mask plate on which pixels of three primary colors, red (R), green (G), and blue (B) are arranged. Process. In projection exposure, R,
It is necessary to align the G and B pixels at predetermined positions on the liquid crystal substrate.

[0003] Also in the fabrication of semiconductor IC, it has been conducted a method of projection exposure the pattern wiring on the wafer from the mask plate are made Sega fit position by alignment marks conventionally for this purpose. FIG. 3 shows the alignment marks used on the IC mask plate and the wafer, and their positions.
Indicates a location registration method, provided #-shaped mark in a suitable two places of the mask plate 1 (M) inclined by 45 °, also respectively form × shaped mark (C) by etching the wafer 2
To achieve . In the exposure, the two are superimposed and the image of each mark is received by the CCD sensor by the optical system. As shown, the center of mark M is M ₀ , and the center of mark C is C ₀ .
₀ , the mark C is at the position shown by the dotted line, and C ₀ and M ₀
Are not coincident with each other, the moving mechanism moves the wafer 2 to X
Alternatively, they are moved in the Y direction so that they match. By performing this for two marks, the wafer is aligned with the mask plate.

FIG. 4 shows a case where the above method is applied to a liquid crystal substrate. In FIG. 4 (a), three mask plates 3 _R , 3 _G and 3 _B for three primary colors are used as a set. Liquid crystal substrate 4
Are sequentially aligned and exposed, and the respective patterns are transferred. However, there is a case where one mask plate is commonly used for the three primary colors, and as shown in (b), the arrangement of the pixels of each color is sequentially changed.
Is a pixel part of a certain color is transparent and the other part is shielded from light. When these parts are sequentially moved at the pixel pitch, 3
The pixels of each color are aligned. In (c),
The inclined # -shaped marks M are provided at two places of one set or one mask plate, respectively.
Three X-shaped marks C _R , C _G , and C _B are provided at the locations.
The center of the mark M is set to the marks C _R , C _G , and C _B by the above method.
, The liquid crystal substrate can be aligned with the pixels of each color.

[0005]

In the alignment method shown in FIG. 4C, three X-shaped marks C _R ,
For C _G, is C _B are separated from each other, it is not simultaneously receiving a CCD sensor, is likely to occur to mistaking the color-coded in alignment. If they are mixed, the liquid crystal substrate will be completely defective. On the other hand, if the whole image is simultaneously received by the CCD sensor as one code instead of three spaced X-shaped marks, there is no fear of misunderstanding. The present invention has been made in view of the above, and is provided with a substrate mark of one code on a liquid crystal substrate, whereby a liquid crystal substrate can be aligned with pixels of each color of a mask plate for three primary colors.
An object of the present invention is to provide a method for aligning a liquid crystal substrate .

[0006]

SUMMARY OF THE INVENTION The present invention is a method of aligning a liquid crystal substrate for color which achieves the above-mentioned object. Two sets of the line segments provide mask marks orthogonal to each other with respect to the other set. Also, two lines corresponding to the mask mark on the liquid crystal substrate, one straight line parallel to one parallel two line segment of the mask mark, and each point corresponding to each color pixel of the mask plate with respect to this one straight line. There is provided a substrate mark plate of one code composed of three line segments orthogonal to each other at points. The data of the interval of two parallel lines of the mask mark and the data of each interval of three lines of the substrate mark are stored in the memory in advance. The optical system simultaneously receives three lines of the substrate mark and two lines of the mask mark parallel to the substrate mark, and positions the line segments in a direction orthogonal to these line segments.
The liquid crystal substrate is moved by the moving mechanism with reference to each interval data stored in the memory, and the center points of two lines of each mask mark parallel to the three lines are detected by the two substrate marks. The liquid crystal substrate is aligned with the pixels of each of the three primary colors on the mask plate by matching one of the three line segments at the corresponding three points.

[0007]

In the above, when the center point of the two mask marks coincides with the corresponding three points of the two substrate marks by moving the liquid crystal substrate by the moving mechanism, the pixel of each color of the mask plate is The liquid crystal substrates are respectively aligned. In this case, since the board mark has one code,
Overall there is no fear that mixing up the different is receiving color re Niasensa Te direction <br/> smell at the same time perpendicular to the line segments in a three-point of the liquid crystal substrate is reliably positioned with respect to each color of the pixel.

[0008]

DETAILED DESCRIPTION FIG. 1 shows an embodiment of the present invention, (a), the three sheets 1 set of masks plate 3 _R, 3 _G, 3 _B 1 masks plate 3 or is shared by the respective colors, At appropriate two places, two sets of two equally-spaced parallel line segments are orthogonal to each other.
Write each. On the liquid crystal substrate 4, each mask mark M
Is written in the position corresponding to the symbol “┼┼┼”. The center of each triangle is made to correspond to each color pixel of the mask plate.
The material of each mark and its reflection performance will be described. For the mark M, a metal film having a high reflectance is used, and for the mark D, a material having a matte color and an appropriate color smaller than the liquid crystal substrate is used. You. Due to such a difference in reflectance,
The reflected light of the mark M has a positive polarity and the mark D has a negative polarity with respect to the level of the reflected light of the substrate. FIG. 1 (b) shows the spacing dimension and direction of each mark, the mask mark M, and its parallel two line segments M _1, M ₂ and M _3, the interval of M ₄ is equal w _0. Board mark D
Is a line segment D ₀ , and three line segments orthogonal to the line segment corresponding to the pixels of each color are D _R , D _G , and D _B. These intervals d ₀ correspond to the pixels of each color as described above. And an integral multiple of that interval. Direction of each _{mark, M 1, M 2, D} 0 in the Y direction, M _3, M
_4, D _R, D _G, the D _B and X direction and advance in the memory in the storage spacing w ₀ and d _0.

FIG. 2 illustrates the alignment procedure for the above. Each mark is simultaneously received by a linear sensor by an optical system, and the position of each line of each mark is detected. (a)
Indicates an alignment method in the X direction. The parallel sensor M provided by the linear sensor provided in the illustrated _SX direction
_{It is} assumed that pulses p ₁ , p ₂ and p _d for ₁ , M ₂ and the line segment D ₀ of the mark D are detected. In this case, assuming that the level of the reflected light from the liquid crystal substrate is 0, p ₁ and p ₂ have a positive polarity and p _d has a negative polarity. Now, when p _d is not at the center of p ₁ and p ₂ as in (a), the interval between p _d and p ₂ is w _x, and w ₀ stored in the memory is referred to as (w
₀ / 2−w _X ) is calculated, and when the liquid crystal substrate 4 is moved in the X direction by the moving mechanism so that this value becomes zero, the alignment in the X direction is performed as shown in (b). Then (b) shows a method of aligning the Y direction, a linear sensor provided in the direction of the illustrated _{S y, M 3, M 4} , D R, D G, pulse p ₃ for D _B, p ₄ and p _R, and p _G, it is p _B was detected. When the pixel and red (R), p ₃ and when p ₄ is in the dotted line position, calculates the distance d _y in their center and D _R, Y direction liquid crystal substrate so that this value becomes zero Is moved to the position indicated by the solid line in FIG. In the above description, the positions of the respective pulses are different from each other, but in some cases, there are overlapping pulses. In such a case, since the total number of pulses is one less, it is immediately known, and when the liquid crystal substrate is moved an appropriate distance, the total number becomes predetermined and the above-described alignment can be performed. By performing the above-described alignment in the X and Y directions for the two marks, the alignment with respect to the pixel R is completed. Similar alignment is performed for the pixels G and B. in this case,
Since the three pulses p _R , p _G , and p _B of the mark D are always detected at the same time at the interval d ₀ (however, if there are no three pulses, the pulse moves as described above), there is no concern that a mistake such as a mistake may occur. . Further, since each pulse of the mark M and each pulse of the mark D have different polarities, they can be easily distinguished.

[0010]

As described above, in the alignment method according to the present invention, the center mark of the mask mark provided on the mask plate for the three primary colors corresponds to the substrate mark provided on the liquid crystal substrate. The liquid crystal substrate is aligned by aligning the three points, and the substrate mark is 1
Therefore, the whole image is simultaneously received by the linear sensor in a direction orthogonal to each line segment at the above three points, and there is no fear of mixing by color, and the alignment with respect to the pixels of each color is securely performed. There is a large portion that contributes to the exposure operation of the liquid crystal substrate.

[Brief description of the drawings]

1A and 1B show an embodiment of the present invention, wherein FIG. 1A is a layout diagram of a mask mark M provided on a mask plate of three primary colors and a substrate mark D provided on a liquid crystal substrate, and FIG. FIG.

FIG. 2 is an explanatory diagram of a positioning procedure for FIG.

FIG. 3 is an explanatory diagram of an alignment mark used for exposing a semiconductor wafer and an alignment method.

4A and 4B are explanatory diagrams of an exposure operation for a liquid crystal substrate for color, wherein FIG. 4A shows a set of three mask plates and a liquid crystal substrate for three primary colors, FIG. 4B shows an array of pixels of three primary colors, FIG. 4C is a configuration diagram of one mask plate shared by the three primary colors, and FIG. 4C is an explanatory diagram of a positioning method using the positioning marks of FIG.

[Explanation of symbols]

1 ... mask plate, 2 ... wafer, 3 ... 3 primary color mask plate, 3 _R ... for red, 3 _G ... green,
3 _B : blue, 4: liquid crystal substrate, M: mask mark, D: substrate mark.

Claims (1)

(57) [Claims] In a projection exposure of a mask plate for three primary colors of red, green and blue to a liquid crystal substrate for color,
At two appropriate places on the mask plate, two sets of equidistant parallel line segments are provided as a set, and two sets of mask marks are provided orthogonal to each other with respect to the other set. At two places corresponding to the mark, one line segment parallel to one parallel two line segment of the mask mark, and three points corresponding to pixels of each color of the mask plate with respect to the one line segment. A substrate mark of one code composed of three orthogonal line segments is provided, and the data of the interval between two parallel lines of the mask mark and the data of each interval of the three lines of the substrate mark are stored in a memory in advance, and the The three line segments of the substrate mark and the two line segments of the mask mark parallel thereto are simultaneously imaged, and the positions of these line segments are linearly adjusted in a direction orthogonal to these line segments.
The liquid crystal substrate is moved by a moving mechanism with reference to each interval data stored in the memory and detected by the sensor, and the center point of the two lines of each of the mask marks parallel to the three lines is set to the two points. By matching one of the three line segments at the corresponding three points of the board mark at the location,
A method of positioning a color liquid crystal substrate, comprising: positioning the liquid crystal substrate with respect to pixels of each color of the mask plate.