JPH0154854B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field> The present invention relates to an exposure apparatus, and particularly to an exposure apparatus suitable for exposing a necessary circuit pattern on a substrate in the process of manufacturing a large liquid crystal display panel.

<Prior Art> Conventionally, various types of exposure apparatuses of this type are well known in the field of semiconductor manufacturing. For example, various types of devices are known, such as contact, proximity, mirror projection, and lens projection devices. Contact and proximity type equipment exposes the wafer to the pattern on the mask by simultaneously illuminating the entire area of the mask with the mask and wafer in contact or in close proximity, while mirror projection type equipment uses a convex mirror and a concave mirror. The mask and wafer are related to each other using a mirror projection system that combines them, and exposure is performed by moving the mask and wafer integrally with respect to the mirror projection system while illuminating the mask in an arc. Further, in a lens projection type apparatus, a pattern on a mask is reduced and projected onto a wafer using a projection lens system, and the mask is illuminated and exposed while moving the wafer step by step.

Incidentally, in recent years, this type of equipment has become capable of exposing large screens in order to cope with the increase in diameter of wafers in order to reduce chip costs in the semiconductor manufacturing field and the manufacture of large liquid crystal display panels. It's been requested. However, manufacturing a large mask compatible with the aforementioned large-diameter wafer or glass substrate that will become a liquid crystal display panel, and transferring the integrated circuit pattern and pixel pattern on the mask to the wafer or substrate all at once requires the following steps. A problem arises.

(1) The dimensions of the mask must be larger than the outer dimensions of the wafer or substrate, but the larger the mask, the more difficult it is to manufacture the mask.

(2) The flatness accuracy of wafers and substrates decreases as the size increases, so it becomes difficult to perform high-resolution transfer over the entire surface due to poor adhesion to the mask, gap variations, defogging, etc., and yields decrease. descend.

(3) As the exposure area expands, the illumination optical system, projection optical system, etc. must be increased in size, making it difficult to manufacture each optical system and requiring a large installation space for the equipment. .

(4) It becomes difficult to uniformly illuminate the exposed area.

(5) Misalignment between the mask and the wafer or substrate due to temperature changes increases in proportion to the distance from the exposure center, resulting in a decrease in alignment accuracy at the edges of the wafer or substrate.

<Purpose of the Invention> The present invention was made in view of the above problems, and its purpose is to make it possible to transfer a predetermined pattern efficiently and with high precision to the entire large-diameter wafer or display substrate. The purpose of the present invention is to provide an exposure device.

In an exposure apparatus for creating an integrated pattern on the target substrate, the pattern is formed by connecting a plurality of identical partial patterns, and a mask having the partial patterns is used to form a pattern. an exposure means (illumination system) for exposing one of the plurality of regions on the substrate with the illumination light; and a mask for rotating the mask by at least 90 degrees within the illumination region of the illumination light for each exposure by the exposure means. a rotation means (mask stage rotation device); and substrate movement for moving the substrate in linear steps in order to sequentially move each area on the substrate to a position to be exposed through the mask every time the exposure means performs exposure. Means (substrate stage)
This is achieved by having the following.

<Description of Examples> Hereinafter, the present invention will be described in detail based on examples shown in the drawings.

FIG. 1 shows an embodiment of an exposure apparatus of the present invention, in which a proximity type of the above-mentioned exposure types is used. In this figure, 1 is a mask on which a large number of pixels forming the screen of a liquid crystal display board and a circuit pattern such as a switching transistor for controlling the on/off of each pixel are formed, and 2 is a mask 1. The optical axis 7 is moved by the motor 4 on the mask stage which is held by suction.
By being rotated around , the direction of the pattern on the mask 1 is changed. Reference numeral 5 denotes a glass substrate which can be used as a liquid crystal display panel by transferring the pattern on the mask 1 using a normal photorinography procedure, and has a rectangular shape with a diagonal of about 14 inches.

6 illuminates the mask 1 with light of a specific wavelength from a light source (not shown), and exposes the photosensitive layer on the substrate 5 through the pattern on the mask 1.
This is an illumination optical system for making it possible to transfer the above pattern onto the substrate 6. Hereinafter, its optical axis 7 will be referred to as the Z direction and the optical axis 7.
The two orthogonal directions in the plane perpendicular to
It's called direction. Reference numeral 8 denotes a substrate stage for holding the substrate 5, which is configured to be able to move the substrate 5 in each of the X, Y, Z, and θ directions. The substrate 5 is arranged close to the mask 1 in the Z direction, and
The stage 8 moves stepwise in the X and Y directions so that any part can face the stage 8. The step movement of the stage 8 is controlled by a precision length measurement system using a laser interferometer.

9 is an alignment optical system for aligning the mask 1 and the substrate 5, and includes two objective lenses 9.
a and 9b, the substrate 5 can be observed at two places simultaneously through the mask 1 and the mask 1.

Next, the operation of this embodiment will be explained. First, mask 1 is set on mask stage 2. As shown in FIG. 2a, the mask 1 has a pixel pattern 1a for forming a liquid crystal screen on a substrate 5 and a circuit pattern 1b for controlling the driving of each pixel.
The mask 1 is set so that its center coincides with the optical axis 7, and is fixed on the mask stage 2 so that the mirror field line around the pixel pattern 1a is parallel to the X direction or the Y direction. Thereafter, the substrate 5 is transported onto the substrate stage 8 by a transport means (not shown). Since the substrate 5 is pre-aligned during transportation and then transported onto the stage 8, when it is fixed on the stage 8, the partial region 5a is approximately aligned with the mask 1a at the exposure position. When the substrate 5 is fixed to the stage 8,
The Z drive system of the stage 8 drives the substrate 5 in the Z direction based on the output of a gap sensor (not shown) so that the mask 1a and the substrate 5 are parallel to each other and the distance between them is minute, for example, within 30 μm.

Thereafter, the X, Y, and θ drive systems of the stage 8 are controlled via the alignment optical system 9 to align the mask 1 and the portion 5a of the substrate 5. After the alignment is completed, light from the illumination system 6 is controlled. The mask 1 is illuminated with light to expose the portion 5a of the substrate 5.
Thereby, the pattern of the mask 1 is transferred to the portion 5a of the substrate 5.

When the transfer of the pattern onto the portion 5a is completed, the mask stage 2 is rotated 90 degrees clockwise by the motor 4 to change the direction of the pattern on the mask 1 to the second direction.
Set as shown in Figure b. At the same time, the substrate stage 8 moves stepwise in the arrow direction (X direction).
As shown in FIG. 2b, a portion 5b of the substrate 5 is placed opposite the mask 1. After this, alignment in the X, Y, Z, and θ directions is performed in the same way as in the previous case, and the pattern of mask 1 is as shown in Figure 2b.
The image is transferred onto the portion 5b of the substrate 5 in a 90° rotated state. Thereafter, as shown in FIGS. 2c and 2d, the 90° rotation of the mask stage 2 and the step movement of the substrate stage 8 are repeated every time the illumination of the mask 1 is completed, and the pattern of the mask 1 is is transferred onto portions 5c and 5d of the substrate 5 while changing the direction by 90 degrees. As a result, a liquid crystal screen is formed in the central portion of the substrate 5 by four slightly overlapping pixel patterns 1a, and a control circuit for controlling the liquid crystal screen is formed around the liquid crystal screen.

Note that when transferring the pattern of the mask 1 to the substrate 5, the remaining 3/3 of the substrate 5 that is not facing the mask 1 is
The portion 4 is shielded from illumination light.

Next, an embodiment of the mirror projection type will be described with reference to FIG. 3. In this figure, the same reference numerals are given to the same functions as in the previous embodiment. 10 is mask stage 2
A mask stage rotation device 11 rotates the mask pattern in a predetermined position by the mask stage 2 onto the substrate 5.
A well-known mirror projection system consisting of a combination of a concave mirror and a convex mirror projects upward at the same magnification. Reference numeral 12 denotes a gap sensor for detecting the distance between the focal plane of the projection system 11 and the surface of the substrate 5, such as an air microsensor, a substrate 5 This is a photoelectric type sensor that detects the distance using reflected light from the sensor. Gap sensor 12
A plurality of are provided, and the distances to the focal plane are detected for a plurality of points on the surface of the substrate 5. 13 is a LAB (linear air bearing) that can be moved along two guide rails 14 provided in the Y direction (perpendicular to the plane of the paper), one of which is of the X and Z direction restraint type and the other of which is the Z direction restraint type. being done. Note that the optical axis of the projection system 11 coincides with the optical axis 7 of the illumination system 6.

Reference numeral 15 denotes a holder that holds the mask stage 2, substrate stage 8, and mask transport device 10 in a fixed relationship, and by being supported by the LAB 13, the mask 1 and substrate 5 can be moved integrally with respect to the projection system 11. It is said that 16 is a base on which an illumination system 6 for illuminating the mask 1, a mirror projection system 11, and a guide rail 14 are attached in a fixed relationship; 17 is a base for transporting the substrate 5 in the substrate storage section 18 to the substrate stage 8; The substrate 5 taken out from the storage section 18 via the belt 17 is fixed on the stage 8 after being subjected to a predetermined pre-alignment. The stage 8 moves the substrate 5 to the holder 15 in X, Y, Z,
It is movable in each direction of θ, and the amount of movement in the X and Y directions is controlled by a length measurement system using a laser interferometer. Other configurations, functions, etc. are the same as in the previous embodiment.

Next, the operation of this embodiment will be explained using FIG. 4. In this figure, the transfer of the pattern to the portion 5a of the substrate 5 is completed, and the pattern of the mask 1 is transferred to the portion 5b. However, the operation starts from the time when the transfer of the pattern to the portion 5a is completed. Let's do it.

When the transfer of the pattern onto the portion 5a of the substrate 5 is completed, the mask stage rotation device 10 rotates the mask stage 2 by 90 degrees, thereby changing the direction of the pattern on the mask 1 by 90 degrees. After this, mask stage 2
aligns the mask 1 to a predetermined exposure position by making slight movements in each of the X, Y, and θ directions using a well-known method. At the same time, the substrate stage 8 moves the substrate 5 in steps relative to the holder 15, and sets the portion 5b of the substrate 5 at a position where the pattern of the mask 1 is projected by the mirror projection system 11. This movement is extremely accurately controlled by a laser interferometric measurement system (not shown).

Thereafter, the Z drive system of the stage 8 is operated based on a plurality of pieces of interval information between the focus plane of the projection system 11 and the portion 5b of the substrate 5 detected by the gap sensor 12, and surfaces are matched. When alignment (focusing) in the Z direction is completed, the two alignment marks "+" on the mask 1 and the alignment mark "+" on the portion 5b are projected through the projection system 11 by the objective lenses 9a and 9b of the alignment optical system. The substrate 5 is moved in each of the X, Y, and θ directions until both are observed simultaneously.

When the alignment is completed, the illumination system 6 illuminates the mask 1b so that the illumination area has an arc shape in accordance with the shape of the best image forming area of the mirror projection system 11. In this state, the holder 15 moves at a constant speed in the Y direction (arrow direction) while being guided by the LAB 13. As a result, the mask 1 and the portion 5b of the substrate 5 move integrally with respect to the projection system 11, and the portion 5b is sequentially exposed to the illumination light that has passed through the pattern of the mask 1, so that the pattern is Transferred in the direction shown. When the transfer of the pattern to the portion 5b is completed, the substrate stage 8 and the mask stage rotation device 10 are operated again to move the portion 5c of the substrate 5 to the projection area of the projection system 11, and the mask 1 on the stage 2 is exposed to light. Rotate 90 degrees counterclockwise around axis 7. At this time, the objective lenses 9a and 9b are moved by a predetermined amount in the direction of the arrow (Y direction), so that two alignment marks "+" on the mask 1, which are different from those in the above case, can be observed. Thereafter, repeating the same operation as described above, the pattern of the mask 1 is applied to the parts 5c, 5 of the substrate 5.
d with each image rotated 90 degrees.

The substrate 5 with the mask pattern transferred onto the entire surface is transferred from the stage 8 to the storage section 18 by the substrate transfer device.
transported and stored. During this time, the mask stage rotation device again rotates the mask 1 by 90 degrees and sets it to the initial state. When a new substrate 5 is set on the stage 8, the above-described exposure operation is repeated again.

<Modifications of Embodiments> In the above-mentioned embodiments, proximity and mirror projection types were shown, but the present invention is not limited to these. For example, the projection lens may be It is also applicable to a step-and-repeat lens projection type, a so-called stepper type, which is an enlargement system.

<Effects of the Invention> As described above, according to the present invention, it is possible to expose a pattern on the entire surface of a large-area substrate with high precision, so it is suitable for processing large-diameter semiconductor wafers and large-screen liquid crystal displays. It becomes possible to manufacture display devices. Further, there is no need to increase the size of the projection system for this purpose.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of the exposure apparatus of the present invention, FIGS. 2a, b, c, and d are perspective views for explaining the operation of the embodiment of FIG. 1, and FIG. FIG. 4 is a plan view showing another embodiment of the exposure apparatus of the invention, and FIG. 4 is a perspective view for explaining the operation of the embodiment of FIG. 1a, 1b, 1c, 1d...Mask, 2...Mask stage, 5...Glass substrate, 6...Illumination optical system, 8...Substrate stage, 9...Alignment optical system, 10...Mask stage rotation device , 11
...Mirror projection system, 13...LAB (linear air bearing), 15...Holder.

Claims (1)

[Scope of Claims] 1. An exposure apparatus for creating an integral pattern on a substrate, wherein the pattern is formed by connecting a plurality of identical partial patterns, and a mask having the partial patterns is formed. an exposure means for exposing one of the plurality of regions on the substrate with predetermined illumination light; and a mask for rotating the mask by at least 90 degrees within the illumination region of the illumination light each time the exposure means exposes one of the plurality of regions. and a substrate moving means for linearly moving the substrate in steps to sequentially move each area on the substrate to a position to be exposed through the mask each time the exposure means exposes the substrate. Characteristic exposure equipment.