JPS63175859A - Exposure system for production of liquid crystal substrate - Google Patents

Abstract

PURPOSE:To facilitate the alignment work between a photomask and a liquid crystal substrate material by adopting a projection system as the exposure system for production of a liquid crystal substrate. CONSTITUTION:A photoresist layer is provided on a liquid crystal substrate material 10 consisting of a transparent or semitransparent plate-shaped member; and when the pattern of a photomask 7 is projected and its image is formed by a projection lens or the like to expose the liquid crystal substrate material 10, positions of an alignment mark preliminarily provided on the photomask 7 whose image is formed on the liquid crystal substrate material and an alignment mark provided on the liquid crystal substrate material 10 are observed from under the liquid crystal substrate material, and the position of the photomask or the running or carrying position of the liquid crystal substrate material is so determined that they have prescribed positional relations. Because of the projection system capable of reduction or expansion of the photomask, it is unnecessary to prepare photomasks having a very narrow line width or a large area and it is sufficient if photomasks having a line width easy to draw and a proper size are prepared, and therefore, the rise of the cost is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an exposure method in the manufacturing process of a liquid crystal substrate used in a liquid crystal display.

[Prior art and its problems]

Liquid crystal substrates for LCD displays are generally made of glass with a diagonal size of 50 to 350 mm and a thickness of 0.3 to 1 inch, and in terms of electrical circuits, transparent electrodes, diodes, transistors, or the like are used. Wiring and the like are provided to connect the two, and its manufacture includes the process of transferring and exposing the pattern of a photomask several times, similar to the rC device.

Conventionally, for transfer exposure, the positional relationship between the photomask and the substrate material is either a contact type or a proximity type. However, as with IC devices, when miniaturization is required or a larger display area is required, it is relatively easy to align the photomask and substrate material by observing from above. , problems arise in the following points.

First of all, as mentioned above, in the conventional contact method and proximity method that use the same magnification, as the pattern of the liquid crystal substrate to be manufactured becomes finer, the pattern of the photomask becomes finer in proportion to the finer pattern. must be prepared,
It is difficult to manufacture and causes an increase in costs.

Second, as the size of the liquid crystal substrate increases, in the two conventional methods that use the same magnification, a photomask must be made larger in proportion to the increase in size, which causes an increase in cost.

Thirdly, the above-mentioned proximity method requires that the surface on which the photoresist layer is provided and the photomask have the same gap everywhere, and that striking parallelism is required, but the liquid crystal substrate to be manufactured is When a large photomask is used as the size of the photomask becomes larger, the parallelism inevitably deteriorates due to warping of the photomask. As a result, the exposed image may be distorted, or in severe cases, the photomask and photoresist may come into contact with each other, causing the photomask to become dirty or scratched, resulting in the production of defective products, as in the case of the contact method.

Therefore, in the present invention, we have considered adopting a projection method as an exposure method for manufacturing printed circuit boards, similar to the exposure method for manufacturing ICs and the like. This is because with the projection method, a photomask is manufactured to a size that is easy to manufacture even when the liquid crystal substrate pattern to be manufactured becomes finer or the substrate becomes larger, and then enlarged exposure or reduced exposure is performed. This has the advantage that a predetermined exposure can be carried out using the first mask, and there is no need to worry about distortion of the image due to warping of the first mask or staining or scratching of the photomask due to contact with the photoresist.

However, alignment is not as easy as with the contact or proximity methods, so we adopted the projection method while taking this alignment method into consideration.

[Purpose of the invention]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method in which a projection method is adopted as an exposure method in manufacturing a liquid crystal substrate Fj, and the positional relationship between a photomask and a substrate material can be easily adjusted.

[Structure of the invention and its effects]

In order to achieve this object, the exposure method of the present invention provides a photoresist layer on a liquid crystal substrate material made of a transparent or semitransparent plate-like member, and projects and images the pattern of a photomask using a projection lens or the like to form the liquid crystal substrate material. Before exposing the liquid crystal substrate material, the alignment marks formed on the photomask and the alignment marks formed on the liquid crystal substrate material are observed in advance from below the liquid crystal substrate material, and the predetermined positional relationship is determined. The present invention includes a step of determining the position of the photomask or the movement or conveyance of the liquid crystal substrate material so that the position of the photomask or the liquid crystal substrate material is determined.

Since the material of the liquid crystal substrate is transparent or semi-transparent, it is not necessary to place the observation system in the direction where the projection optical system is placed for observation, but rather to place the observation system in the opposite direction where the projection optical system is located. It is easier to design and manufacture the device, and it is easier to perform the observation work. Moreover, as mentioned above, since the material is transparent or translucent, the observation itself is not affected.

〔Example〕

One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic explanatory diagram of an optical system for explaining an embodiment. In the figure, 1 is a short-arc type ultra-high pressure mercury lamp, such as a TLSlI500D with an extinguisher power of 500W (
Ushio Inc.! ! ri, 2 is elliptical focusing! i23 and 5 are cold mirrors for cutting off heat rays, 4 is an integrator lens, 6 is a projection lens, 7 is a photomask, 8 is an imaging lens, 10 is a liquid crystal substrate material, and 9 is an observation means such as a mirror. 11 is the human eye. Although the resist film on the liquid crystal substrate material is omitted, the photosensitive exposure wave area is 500.
A novolac positive resist of nm or less can be used.

The thickness may be approximately 2 μm. The integrator lens 4 is used to obtain a substantially uniform illuminance distribution on the exposure surface.

The condenser lens unit 6 is for appropriately allowing a beam of light to enter the imaging lens, and is not limited to the configuration shown in the figure. Needless to say, the imaging lens 8 is for condensing the light emitted from the photomask onto the exposure surface to form an image of the pattern of the photomask. is placed so that the focal point of the image is located.

To give an example of dimensions, the size of the illuminated part of the photomask is 114 mm x 53 mm, and the size of the board material - frame is 57 mm.
It is mm x 26.5mm. Therefore, it is a reduction exposure with a magnification of about 1/2, and the line width of the projected pattern is 2
It is about 0 μm.

By the way, as an observation system for the alignment mark, mirror 9 is shown in Figure 1, but in reality it is better to use a microscope equipped with an objective lens and an eyepiece, and if the focal length of the objective lens is small, , insert an imaging lens in the middle. As described above, since these observation systems are provided on the opposite side from where the projection optical system is located, not only is the device easy to design and manufacture, but also the observation work is easy. Alignment can be done by adjusting the position of the photomask, or by setting the photomask at a fixed position and moving the liquid crystal substrate material so that the running or transporting position is at a predetermined fixed position. Alternatively, the conveyance system (not shown) may be adjusted.

〔Effect of the invention〕

As can be understood from the embodiments described above, the present invention allows for easy alignment of the photomask and the liquid crystal substrate material when a projection method is adopted as the exposure method in manufacturing the liquid crystal substrate, Because it uses a projection method that can be reduced or enlarged? I
It is no longer necessary to prepare a photomask with a large line width or a photomask with a large area, and while it is sufficient to make a photomask with an easy-to-make line width or a photomask with an appropriate size, cost increases are suppressed. There is also no need to worry about stains or scratches on the photomask due to contact between the photomask and photoresist, or distortion of the image due to warping of the photomask.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of one embodiment of an optical system for implementing the present invention. In the figure, 1 is an ultra-high pressure mercury lamp, 2 is an elliptical condenser, 3 and 5 are cold mirrors, 4 is an inch greater lens, and 6
7 is a projection lens, 7 is a photomask 8 is an imaging lens, 9 is a mirror, and 10 is a liquid crystal substrate material. Condolence-■

Claims (1)

[Claims] A photoresist layer is provided on a liquid crystal substrate material made of a transparent or translucent plate-like member, and the pattern of the photomask is projected and imaged with a projection lens etc. to expose the liquid crystal substrate material in advance. The mutual positions of the alignment marks formed on the photomask and the alignment marks formed on the liquid crystal substrate material, which are imaged on the liquid crystal substrate material, are observed from below the liquid crystal substrate material. An exposure method for producing a liquid crystal substrate, which is characterized by determining the position of a mask or the movement or transport of a liquid crystal substrate material.