JPS61247027A - Projection exposure equipment - Google Patents

Abstract

PURPOSE:To prevent deterioration in relative positioning accuracy between a original sheet and a body to be exposed and in relative position accuracy between the patterns obtained by divided printing, by holding the bottom surface of the carriage transporting the original sheet and the body to be exposed in a body so as to slide freely in the direction of the transportation to the base stand loaded with the main body of exposure equipment. CONSTITUTION:The carriage (holder) 9 transports the original sheet 1 such as the mask, etc. and the body to be exposed 3 in a body. The bottom surface of the carriage (holder) 9 is so held that it can slide freely in the direction of the transportation to the base stand 13. For example, the air jet pad 15 is installed on the bottom surface of the holder 9, and the linear bearing is constituted to support the bottom surface of the holder 9 with the pad 15 and the guide rail 16 installed on the base stand 13. The pad 15 is supported through the spherical base 20a of the fixture 20, so as to equalize automatically to the upper surface of the guide rail 16 when the holder 9 travels in the direction of Y. Thus, the shape of the carriage is more stabilized and the more precise printing is available.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to an exposure apparatus that prints a pattern image on an original plate, such as a semiconductor circuit, onto an exposed object, and particularly relates to a step-and-scan method that prints a large screen in parts. The present invention relates to a projection exposure apparatus having a suitable shape.

[Description of the Prior Art] In a mirror projection type semiconductor printing apparatus, a mask and a cover plate (or wafer) are placed on a carriage, and the entire screen is exposed by scanning and moving the carriage onto the exposure surface.

However, as recent trends have shown that screens have become larger due to larger diameter wafers to reduce chip costs and the manufacture of large liquid crystal display panels for LCD TVs, the exposure range has become larger. In addition, there is a problem in that the device becomes larger due to the need to increase the span length.

As a countermeasure to this problem, a step-and-scan printing method has been considered in which the screen is divided and scan printing is performed multiple times. In order to perform this step-and-scan printing at higher speed and with higher precision, it has been considered to mount a substrate stage (X, Y, θ stage) on the carriage.

By the way, this substrate stage is relatively heavy, for example, about 40 kq, and on the other hand, the carriage tends to have a flexible structure due to the need for weight reduction. Therefore, when the substrate stage 4 is mounted on the carriage 9 as shown in FIG. 4, the carriage deforms as shown by the dotted line. Further, this deformation changes depending on the movement of the center of gravity position due to the step movement of the substrate stage 4. For this reason, a relative deviation occurs between the positioning reference of the mask 1 and the positioning reference of the substrate 3, and especially when exposing the mask and the substrate in accordance with their respective absolute standards, such as in the first mask printing process, the pattern printed in parts is There have been disadvantages such as the relative positional accuracy of the patterns being reduced and the patterns overlapping each other, being spaced too far apart, and creating steps between the patterns.

[Object of the Invention] In view of the above-mentioned problems, the present invention reduces the deformation of the carriage without increasing the strength and weight of the carriage itself, and
The object of the present invention is to prevent deterioration in the relative positioning accuracy between an original plate such as a mask and an exposed object such as a substrate, and the relative positional accuracy between printed patterns with respect to the exposed object.

[Explanation code for the example] Hereinafter, the present invention will be explained in detail using the drawings.

Note that parts common or corresponding to those of the conventional example are represented by the same reference numerals.

FIG. 1 is an overall configuration diagram of a step-and-scan type mirror projection exposure apparatus according to an embodiment of the present invention. In the figure, 1 is a photomask on which a printed pattern is formed, and 2 is a photomask with mask 1 mounted on it.
, a mask stage movable in the θ directions. 3 is a glass substrate on which a large number of pixels and switching transistors for controlling on/off of these pixels are formed by normal photolithography procedures in order to manufacture a liquid crystal display board, and the length of the diagonal line is is about 14 inches square. 4 holds the board 3 and moves X, Y.

The substrate stage is movable in the θ direction, and by stepping to four positions, it is possible to expose the substrate 3 in four parts. Reference numeral 5 denotes a well-known mirror projection system consisting of a combination of a concave mirror and a convex mirror, which projects the pattern image of the mask 1 aligned at a predetermined position by the mask stage 2 onto the substrate 3 at the same magnification.

Reference numeral 6 denotes an illumination optical system that illuminates the mask 1 at the exposure position with light of a specific wavelength from a light source (not shown), and by exposing the photosensitive layer on the substrate 3 through the pattern on the mask, This is to enable the pattern to be transferred onto the substrate 3. Note that the optical axis of the projection system 5 is made to coincide with the optical axis of the illumination system 6.

7 is a LAB (linear air bearing) that can be moved along two guide rails 8 provided in the Y direction (perpendicular to the page), one of which is movable in the X direction (horizontal direction of the page) and the Z direction (direction perpendicular to the page). (vertical direction) restraint type, and the other is a Z direction restraint type. 9 is a holder (carriage) that holds the mask stage 2 and substrate stage 4 in a fixed relationship;
7, the mask 1 on the mask stage 2 and the substrate 3 on the substrate stage 4 can be integrally transferred. By one movement of the holder 9, the substrate 3 is exposed by 1/4 of each mask 1.

Reference numeral 11 denotes a mask conveying device, on which a plurality of masks 1 are set, and conveys a desired mask to the mask stage 2.

Reference numeral 12 denotes a gap sensor for detecting the distance between the focal plane of the projection system 5 and the surface of the substrate 3, and is, for example, an air microsensor or a photoelectric type sensor that detects the distance using reflected light from the substrate 3.

Reference numeral 13 denotes a base on which the projection system 5, illumination system 6, and guide rail 8 are mounted in a fixed relationship.

Next, reference numeral 15 denotes an air jetting pad, which is a feature of the present invention, and a guide rail 1 provided on this pad 15 and the base 13.
6 constitutes a LAB for indicating the bottom surface of the holder 9. As shown in FIG. 2, the pad 15 is
When the holder 9 moves in the Y direction, it automatically follows (equalizes) the upper surface of the guide rail 16. The fixture 20 is fixed to the bottom surface of the holder 9 with screws 21. 22
23 is a spring for urging the pad 15 toward the spherical seat 22a, and 23 is a vibrator for transmitting air from an air supply source (not shown) to the ejection port 15a of the pad 15. Note that the pad 15 may be of a type other than a spherical seat type, for example, a floating type, as long as it can be equalized. If the pad 15 can be equalized in this way,
Mounting is preferred because it reduces the problem of accuracy, making the work easier.

Further, although there is no particular restriction on the number of pads 15 provided on the bottom surface of the holder 9, the substrate stage 4 placed on the holder 9
For example, considering the number of steps in Fig. 3<a)(b)
As shown in the figure, the number can be two or four. In FIGS. 3(a) and 3(b), 01 to 04 indicate the center of gravity of the substrate stage 4 relative to the holder 9 at each stop position when the substrate stage 4 moves in four steps. Figure 3 (a) shows the center of gravity between 0+ and 03 and the center of gravity 02
Fig. 3(b) shows an example in which pads 15 are provided at the center of each of the centers of gravity 01 to 04.
An example is shown below. When a plurality of pads are provided on the holder 9 that moves in the Y direction as in these examples, it is desirable that the ejection pressure of the pads near the current center of gravity by the stage 4 be higher than that of the other pads. Moreover, when using one pad, it may be provided at the center of each center of gravity 01 to 04.

The ejection pressure of the air ejection pad 15 may be constant during the movement of the holder 9, and the air pressure of the LAB 7 may be adjusted to correct magnification errors that occur between the pattern of the mask 1 projected by the projection system 5 and the substrate 3. When controlling to change the attitude of the holder 9, the on/off or strength of the air may be controlled in synchronization with the LAB 7.

In this way, by attaching the air blowing pad 15 to the bottom surface of the holder 9 and supporting the holder 9 on the bottom surface, the holder 9
Even if the substrate stage 4, which is a heavy object, is mounted, deformation is prevented or reduced.

[Effects of the Invention] As described above, according to the present invention, since the bottom surface of the carriage for integrally holding and transporting an original plate such as a mask and an exposed object such as a substrate is supported, Even when an original plate or a stage for mounting an exposed object is mounted on the carriage for the purpose of performing step-and-scan more efficiently, deformation of the carriage can be reduced or prevented, and the original plate and It is possible to prevent a decrease in the relative positioning accuracy with the exposed object and the relative positional accuracy between the patterns that are divided and printed on the exposed object.

Further, even when the present invention is applied to a conventional example in which a substrate stage is not mounted, the shape of the carriage becomes more stable and printing can be performed with higher precision.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of essential parts of a mirror projection exposure apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view showing details of an air jet pad in the apparatus of FIG. 1, and FIGS. ) is a schematic top view of the holder in the apparatus shown in FIG. 1, and FIG. 4 is a sectional view of a main part of a conventional mirror projection exposure apparatus. 1: Photomask, 2: Mask stage, 3: Substrate, 4
: substrate stage, 5: mirror projection system, 9: holder (carriage), 13: base, 15: air jet pad. Figure 1 Figure 2 Figure 3x

Claims (1)

[Claims] 1. After positionally aligning the original plate and the object to be exposed, the original plate and the object to be exposed are scanned integrally with respect to a projection optical system, so that the image of the original plate is transferred to the exposed object. In a projection exposure apparatus that transfers images onto a body, a support that allows the bottom surface of a member that integrally transfers the original plate and the object to be exposed to slide in the transfer direction with respect to a base on which the exposure apparatus main body is mounted. A projection exposure apparatus characterized in that it is supported by means. 2. The projection exposure apparatus according to claim 1, wherein the support means is a fluid ejection pad formed by ejecting fluid onto the upper surface of the base.