JPS63132425A - Correction of reduction aligner - Google Patents

Abstract

PURPOSE:To give precision to the coordinate position by a method wherein multiple alignment marks orthogonally arranged to one another on a stage target are aligned with respective mirrors in X and Y directions to store the coordinate positions for detecting any change orthogonal degree. CONSTITUTION:Alignment marks 22-24 are made near an L type stage target to be aligned with one another, when the stage position coordinates, the distance between the marks 24 and 23 as well as 23 and 22 are respectively assumed to be (XA, YA), (XB, YB), (XC, YC), lx and ly, if (YA-YB)/lx and (XC-XB)/ly are equal, the coordinates are orthogonal but if they are unequal, said coordinates are not to be orthogonal. On these premises, if X=(X'C-X'B)/ly, the orthogonal coordinates can be secured by correcting -Y. X to the movement of stage in the direction of Y.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a correction method for a reduction exposure machine (stepper) that is applied to inspection and adjustment of an optical system of a reduction exposure machine (stepper) in a semiconductor manufacturing apparatus.

(Prior Art) FIG. 4(a) is a plan view showing an example of the configuration of a conventional stepper device, and FIG. 4 (bl is a front view of this stepper device).

In both FIG. 4(a) and FIG. 4tb+, 11
is the X stage, 12 is the Y stage, and X stage 1
1 is driven by a motor 13, and the Y stage 12 is driven by a motor 1.
It is designed to be driven by 4.

The X stage 11 is positioned by a mirror 15, and a laser beam 9 of the laser interferometer length measuring device is made incident on the mirror surface of the mirror 15.

Similarly, the Y stage 12 is positioned using a mirror 16, and the laser 20 of the laser interference length measuring machine is made to be incident on the mirror surface of the mirror 16. In addition, 17 is a sea urchin chuck, and 18 is a wafer.

The position of the mirror surface is measured in the X and Y directions using a laser interferometric length measuring machine, and the results are sent to the X stage 11.
, the positions of the X stage 11 and the Y stage 12 are determined by applying feedback to the motors 13 and 14 that drive the Y stage 12.

(Problems to be Solved by the Invention) This conventional stepper device uses the mirrors 15 and 16 provided in the If the degree of orthogonality changes, the orthogonality accuracy of the stage becomes the orthogonality accuracy of the stage.

As mentioned above, the mirror 15.1 measuring the position coordinates
There is a problem in that when the orthogonality of the stage 6 changes, the change directly leads to an abnormality in the orthogonality of the stage.

In order to solve this problem, there is a method of integrally manufacturing the mirrors 15 and 16 for the X stage 11 and Y stage 12, but this method has the disadvantage that it is difficult to manufacture mirrors with good orthogonality.

This invention solves the problems of the above-mentioned prior art.
A correction method for a reduction exposure machine that solves the problem of abnormalities in stage orthogonality due to changes in mirror orthogonality, and the difficulty in achieving high precision in integrated manufacturing of mirrors for the X stage and Y stage. It provides:

(Means for Solving Problems) This invention provides a correction method for a reduction exposure machine in which a plurality of alignment marks arranged orthogonally on a stage target fixed near the mirror are attached to each mirror in the X direction and the Y direction. In this method, a process is introduced in which the position coordinates of the stage at the time when each alignment mark is completed are stored by aligning the two points at the upper end of each mark.

(Function) According to the present invention, the above-described steps are introduced in the correction method for the reduction exposure machine, so that the error value of the orthogonality of the mirrors in the X and Y directions is calculated from the stored values of the position coordinates of the stage. and within a certain accuracy.

It acts to correct the stage during stepping so as to maintain the orthogonality of the stage in Y, thereby eliminating the above-mentioned problem.

(Example) An example of the correction method for a reduction exposure machine according to the invention of Party B will be described below based on the drawings. Fig. 1 (al is a plan view of the stepper device applied to one embodiment thereof, Fig. 1 fb)
is its front view. This Figure 1(a).

When explaining the configuration in Fig. 1fbl, Fig. 4(a)
.

The same parts as in FIG. 4(b) are given the same reference numerals, and the parts different from those in FIG. 4(a) and FIG. 4(bl) will be mainly described.

This figure 1 (a), figure 1 (bl), figure 4 (a),
As is clear from the comparison with Figure fb), the numbers 11 to 20
The parts indicated by numerals 21 to 24 are the same as those shown in FIG. 4(a) and FIG.
This is a new part added to the bl configuration.

In other words, 21 is a stage target formed in an "L" shape, and alignment marks 22 and 24 are provided near both ends of this stage target 21. ) are also provided with alignment marks 23.

FIG. 2 shows only the necessary parts of FIGS. 1(a) and 1fb), and 25 is an alignment system.

Next, the correction method for the reduction exposure machine of the present invention will be explained using FIGS. 1(a) and 1(bl) and FIGS. Figure 3 (
a) to FIG. 3(C) show the order of orthogonality measurement in this invention.

First, as shown in FIG. 3(al), one alignment mark 24 is aligned using the alignment system 25, and the stage position coordinates are set to (XA, YA).Similarly, as shown in FIG.
b), alignment mark 2 as shown in Figure 3 tC)
2.23, the stage position coordinates are (x,, y6) and (Xo, Yol), and the distance between alignment marks 24 and 23 is (, alignment).
・If the distance between marks 23 and 22111i is 17, then in the case of YA-Y8Xo-X8 xlV, they are orthogonal, but Fig. 3(b) and Fig. 3(C)
This is the case where the mirror 16 changes by 16°, which shows that they are not orthogonal, and the orthogonal system 2 of the stage
5 is as shown by the dotted line in FIG. Here Δx=
x2-x', then by calculating the correction of -Y x ΔX for the movement JIY of the stage in the YY direction, it is possible to secure orthogonal coordinates as shown by the solid line in the figure. .

(Effects of the Invention) As described above in detail, according to the present invention, a plurality of one alignment marks are provided on the stage targetera, and the alignment marks are sequentially aligned using the alignment mark system of the reduction exposure machine. By memorizing the coordinate position at that time and calculating the change in the degree of orthogonality, correction is applied when stepping the stage. It is now possible to compensate for changes, and always maintain a constant M.
It can be kept in a box.

In addition, compared to a method in which the length measuring mirror is formed into an L-shape to maintain orthogonality, it is only necessary to place the alignment mark at right angles within one target. Even if the error is not corrected, it is possible to improve the accuracy by measuring the error and providing it as a correction value using software.

[Brief explanation of the drawing]

FIG. 1 (al is a plan view of a stepper device applied to an embodiment of the correction method for a reduction exposure machine of the present invention, FIG. 1 fb)
1 is a front view of the stepper device, FIG. 2 is a plan view showing the main parts of the stepper device, and FIGS. FIG. 4 (ta+) is a plan view of a conventional stepper device, and FIG. 4 (fb) is a front view of the conventional stepper device. 11...X stage, 12...Y stage, 13°14...motor, 15, 16...mirror, 17...
- Wafer chuck, 18... Wafer, 21... Stage target, 22-24... Alignment mark, 25... Alignment system. Fig. 1 25 Showing the end point 3 1 Biggo (σ),) ゛ 4i solid in Fig. 1 (b)! T's ;T side [Figure 2 book holder B%1g engineering guard! Receipt of uneven rice to customer 90 Goshino ■ Gorge 1 correct procedure amendment (method) % formula % 1 Indication of incident Patent Application No. 163583/1983 2 Title of invention Correction method for reduction exposure machine 3 Person making the amendment “Relationship to the case Patent applicant (029) Oki Electric Industry Co., Ltd. 6 Column for a brief explanation of the drawing to be amended 7 Contents of the amendment

Claims (1)

[Claims] (a) A step of installing a stage target having a plurality of orthogonally arranged alignment marks on a wafer stage; (c) Calculating the orthogonality error of the mirrors for positioning the X stage and Y stage from the determined coordinate positions of the alignment marks; and a process for applying correction during stepping of the Y stage, and a correction method for a reduction exposure machine.