JPH04121605A - Laser interferometer mirror attachment method and stage device using the method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to various measuring machines using a laser interferometer, or an exposure apparatus for forming a pattern on a flat object such as a semiconductor wafer or a liquid crystal display panel. In particular, when manufacturing high-density integrated circuit chips for semiconductor memories and arithmetic devices, it is possible to accurately maintain the posture of the exposed object, such as a sea urchin, on which a circuit pattern is printed, and perform high-precision exposure. The present invention relates to an exposure apparatus for rice cracking.

[Prior Art] Conventionally, this type of device, for example, an exposure device such as a stepper that projects a pattern drawn on a reticle onto a wafer, is equipped with a function to align the reticle and the sea urchin. Exposure was performed after alignment.

This type of alignment is accomplished by measuring the amount of misalignment between the original plate, such as a reticle, on which the pattern to be projected is drawn, and the exposed object, such as a wafer, and adjusting the position of the exposed object based on the results. This was done by moving the original plate and the object to be exposed using laser length measurement control.

In this case, the laser length measurement moon reference mirror is simply fixed on the movable stage directly or via a mounting block, either over the entire surface or at multiple points.

[Problems to be Solved by the Invention] However, in such a device, the difference in expansion and contraction (difference in linear expansion coefficient) between the mirror for laser length measurement and the mirror support stand (or the mounting stage of the support stand) due to temperature changes. This difference causes the mirror to be pulled and deformed or misaligned, which poses problems in overlay accuracy (positioning accuracy) and flexibility with other devices.

In view of the above-mentioned problems of the prior art, the present invention provides extremely high overlay accuracy and high accuracy without causing any misalignment between the exposed object such as a wafer and the mirror even when temperature changes occur during operations such as step operations. The purpose of the present invention is to provide an exposure apparatus with high productivity and high flexibility.

[Means for Solving the Problems and Effects] In order to achieve the above object, the present invention provides a mirror mounting portion of a stage provided with a mirror in the shape of a parallel plate spring. This allows the leaf spring portion to absorb the difference in expansion and contraction between the mirror and the mounting base due to temperature changes, thereby preventing deformation and positional shift of the mirror.

[Example] FIG. 1 is a conceptual diagram of an XY stage controlled by a laser interferometer according to the present invention, and FIG. 2 is a diagram showing a mirror mounting portion thereof taken out. FIG. 3 is a view of the mirror mounting plate (X stage) viewed from above with the mirror seen through, and the mirror support portion has an integral parallel plate spring structure. FIG. 4 specifically shows this integral parallel plate spring structure in an enlarged manner.

In Figures 1 to 4, 1 is a mirror, 2 is a length measurement beam of a laser interferometer, 3 is an X stage (mirror mounting plate), and 4 is a Y
A stage, 5 a motor, 6 a mirror fixture, and 7 a wafer. 8 is a mirror support part.

In FIG. 2, the mirror 1 is fixed to the X stage 3 using a mirror fixing fitting 6. As shown in FIG.

At this time, one side of the mirror support plate 8 has a leaf spring structure as shown in FIG. This enlarged portion is shown in FIG.

The leaf spring has an integral structure with the X stage 3, and in particular has an elastic hinge structure having a hinge portion 10.

Now, considering that there is a temperature change, for example, if an expansion/contraction difference Δ1 occurs between the mirror 1 and the X stage 3, the parallel plate spring will deform in the A direction in Fig. It becomes possible to absorb 61 minutes.

Although the above-mentioned embodiment describes a structure in which the mirror support part has an integral leaf spring structure, a split leaf spring structure in which a pair of spring pieces separate from the stage is attached is also possible. Furthermore, although the parallel leaf spring is provided at one location, an integral or separated parallel leaf spring structure with two or more locations is also possible.

FIG. 5 shows a conceptual plan view of the split structure and the structure of two parallel leaf springs. The mirror support part 8 is connected to the X stage 3 by a pair of parallel leaf spring pieces 9a and 9b, and supports the mirror 1. Two such mirror support parts are provided on one side of the X stage 3 (for one mirror).

[Effects of the Invention] As explained above, according to the present invention, it is possible to eliminate the problem of mirror deformation and misalignment due to temperature changes in an exposure apparatus by using the parallel leaf spring structure of the mirror mounting plate, so that the mirror and the stage can be There is no change in the relative position of the sensor, making it possible to provide extremely high detection accuracy.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the main part configuration of an XY stage according to an embodiment of the present invention, FIG. 2 is an enlarged perspective view of a mirror attachment part of the XY stage of FIG. 1, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a detailed view of the parallel plate spring portion of the mirror mounting plate of FIG. 3; FIG. 5 is a plan view of a mirror mounting plate according to another embodiment of the present invention. It is. 1: Mirror 2: Laser interference measurement length light, 3: x stage (mirror mounting plate), 4: Y stage, 5: motor, 6: mirror fixing bracket, 7: wafer. Patent Applicant Canon Co., Ltd. Representative Patent Attorney Tetsuya Ito Representative Patent Attorney Tatsuo Ito

Claims (4)

[Claims] (1) A mirror provided on the stage is provided to reflect a laser beam from a laser interferometer for measuring the position of a moving stage to be detected, and the mirror is connected to at least one pair of parallel plate springs with respect to the stage. A mounting structure for a laser interferometer mirror for position detection, characterized in that the mirror is mounted through a. (2) Attaching the laser interferometer mirror for position detection according to claim 1, wherein the parallel leaf spring is integrally formed on the side of the stage by processing an integral member with the stage. structure. (3) Laser interference for position detection according to claim 2, characterized in that each spring piece of the parallel plate spring constitutes an elastic member integrated with the stage by forming a hinge by thin wall processing. Mounting structure of meter mirror. (4) The position detection laser according to claim 1, wherein the parallel leaf spring is constructed by attaching a pair of parallel spring pieces separate from the stage to the side sides of the stage. Interferometer mirror mounting structure.