JPS62241329A - Reduction stepper - Google Patents

Abstract

PURPOSE:To enable a distortion value to be easily and high-precisely corrected, by supporting a reticle or a lens-system holding part on micrometers so that its up-and-down height can be adjusted. CONSTITUTION:A lens system is composed of two reducing projection lenses 2 and 2 which are arranged in a fixed distance on the up-and-down parts, and facing to each other on the upper and lower ends of a cylindrical lens holding part 3. With a collar part 3a of the lens holding part 3 brought in contact with the peripheral upper plane of a base board-mounting hole 5a, the lens holding part 3 is held on the base board 5 so that the lens system is placed just above the wafer stage 8. While main bodies 6a of micrometers 6 are installed vertically to the base board 5 and reticle holding parts 4 are supported to be movable up and down on the spindles 6b which extend from the main bodies 6a, a reticle 1 is set horizontally, paralleling the lenses 2, on the upper plane opening part 4a of the reticle holding part 4. Such up-and-down moving in micron units enables the distortion to be corrected and besides a parallel degree of the lenses and the reticle to be adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a reduction projection type exposure apparatus used in an alignment exposure step after coating a photoresist during a semiconductor substrate manufacturing process;
In particular, it relates to a mechanism for correcting lens distortion.

[Prior Art] Conventionally, as a means for correcting lens distortion in a reduction projection exposure apparatus, the thickness of the height adjusting spacer supporting the reticle system or lens system holding part is changed by cutting the spacer. Alternatively, it was common to adjust the distance between the reticle and the lens by replacing the spacer with a new spacer having a different thickness.

[Problems to be Solved by the Invention] In the case of the above-mentioned conventional reduction projection type exposure apparatus, the spacer was removed and shaved or replaced with a new one, so the effect of stress and temperature on the spacer when it was shaved, In addition, problems with fitting in when replacing the spacer with a new one occurred, and a phenomenon occurred in which the distortion value immediately after the spacer was installed fluctuated several days later. Furthermore, since the number of values to be corrected was on the order of a few, it was impossible for anyone to do the work without a highly skilled worker, and the work required a large amount of time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a reduction projection type exposure apparatus that can easily and accurately correct distortion values.

[Means for Solving the Problems] The present invention provides a reduction projection type exposure apparatus in which a reticle and a lens system are installed such that they can be relatively displaced. This is a reduction projection type exposure apparatus characterized by adjustable support.

[Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, a base 5 is installed horizontally directly above the wafer stage 8, and a lens system is set in the mounting hole 5a in the center of the base 5 so as to face up and down. The lens system consists of two reduction projection lenses 2.2 arranged at a constant interval below F, and these lenses 2.2 are mounted facing each other on the upper and lower ends of a cylindrical lens holding part 3. The lens system is installed directly above the wafer stage 8 by bringing the flange 3a of the lens holder 3 into contact with the upper surface of the mouth of the base mounting hole 5a and supporting the lens holder 3 on the base 5.

On the other hand, the main body 6a of the micrometer 6 is mounted perpendicularly to the base 5, the reticle holder 4 is vertically movably supported on a spindle 6b extending from the main body 6a, and the reticle 1 is inserted into the upper opening 4a of the reticle holder 4. While maintaining parallelism with the lens 2, it is calibrated horizontally.

As shown in FIG. 1, the distance between reticle 1 and lens 2 is maintained at 71, and the pattern of reticle 1 is passed through lens 2 and transferred onto wafer 7, resulting in the distortion state shown by the broken line in FIG. Assume that the lattice bulges out relative to the ideal lattice (solid line) as shown in FIG. Now, assuming that DIS (distortion average value at each point) is -(, Σ (Xi +yi))/8, the relationship between the distance Z between the reticule and the lens 2 and DIS is shown in FIG.

In order to bring DIS closer to the ideal grid, Z = Z3 (Figure 3)
Therefore, the spindle 6b of the micrometer 6 is rotated by (Zl-22) to raise it in micron units, and the reticle 1 of the reticle holder 4 is moved away from the lens 2, so that the reticle 1 and the lens The distortion is corrected by increasing the interval between 2 and obtaining a point where DIS=0.

Since the reticle holder 4 is supported by the micrometer 6 and moved up and down in micron units, it is possible to simultaneously adjust the parallelism between the lens and the reticle in addition to correcting distortion.

In the previous embodiment, the reticle holder 4 was replaced with a micrometer 6.
Although the lens holding part 3 is supported by a micrometer 6, the lens holding part 3 may be supported by a micrometer 6.

In one embodiment of the present invention, the lens or reticle system holder has the structure shown in the figure, and the holder is moved up and down directly using a micrometer. The shape and method do not matter as long as the device has a mechanism for moving it up and down using a micrometer.

[Effects of the Invention] As explained above, the present invention makes it possible to easily and accurately correct distortion fluctuations by moving the support point of the reticle or lens system holder up and down with a micrometer, and it is possible to correct distortion easily and with high precision. Sometimes, the parallelism between the lens and reticle can be corrected together, which has the effect of improving work efficiency.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing an embodiment of the present invention, Fig. 2 is a plan view showing distortion when a pattern on a reticle is transferred onto a unihull, and Fig. 3 is a distance between the lens and the reticle (Z). FIG.

Claims (1)

[Claims] (1) A reduction projection type exposure apparatus in which a reticle and a lens system are installed so as to be relatively displaceable, characterized in that a holder for the reticle or the lens system is supported on a micrometer so that its vertical height can be adjusted. A reduction projection type exposure device.