Exposure method

Abstract

The invention provides an exposure method, which comprises the following steps of performing exposure on a photoetching plate and projecting an exposed test pattern on the photoetching plate on a wafer; adjusting an exposure lens, and enabling the exposure lens to move a first stepping distance relative to an x direction of the photoetching plate or enabling he exposure lens to move a second stepping distance relative to a y direction of the photoetching plate; and performing exposure, projection and zooming to the wafer. The first stepping distance is larger than or equal to the dimension of the test pattern in the x direction and smaller than the dimension of the photoetching plate in the x direction. The second stepping distance is larger than or equal to the test pattern in the y direction and smaller than the dimension of the photoetching plate in the y direction. Compared with the prior art, the exposure method has the advantages of reducing the influence of warp of the wafer on a test point, improving accuracy of test results, being capable of utilizing an normal wafer to detect bending of the image surface of a photoetching machine simultaneously, reducing or eliminating use of a double-faced polished sheet, and having low cost.

Description

【Technical field】 [0001] The invention relates to an exposure method, in particular to an exposure method for testing the curvature of an image plane of a photolithography machine. 【Background technique】 [0002] The field curvature of the lithography machine is an important index to evaluate the performance of the lithography machine. With the progress of the lithography machine manufacturing technology, the control of the field curvature has been fully improved, and the image within the entire usable range of the lens The curvature of the face can be less than 0.1 microns. [0003] Such as figure 1 As shown, it is the layout of the photolithography plate 10 at the image surface curvature test point of the existing lithography machine. The test structure of each pattern 11 is consistent, and the exposure area of ​​the photolithography plate 10 is the maximum range allowed by the lens of the lithography machine, and it must be Make sure there is a figure 11 on the edge of ...

AI Technical Summary

Problems solved by technology

If the flatness test process is artificially skipped, the resulting data is too noisy to be analyzed

In addition, the double-sided polishing sheet is used many times, and after several thermal processes, deformation will occur, and the flatness cannot meet the requirements

Therefore, during the daily maintenance of the lithography machine, it is necessary to frequently use new double-sided polishing sheets to test the curvature of the image plane, which is extremely costly

[0011] At the same time, even if it is a double-sided polished wafer, the wafer still has a certain degree of warpage, so the focal length during exposure is the sum of the program setting value and the wafer warpage, and the wafer warpage is unpredictable, resulting in the final measurement being The line width-focal length curve cannot be fitted normally, and the final focal length cannot be correctly judged

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