Method and system for measuring stray light

Abstract

The invention provides a method for measuring stray light. The method comprises the following steps of: S1, initializing a displacement platform; S2, setting measuring parameters of a measuring system; S3, driving the displacement platform by a driving motor to scan an illumination light field region, performing light energy detection on a test point on a mask surface or a silicon slice surface by using a point energy detector, fixing the point energy detector at the position of a test point, adjusting the size of an opening of a changeable slit to obtain light energy values of the same test point at different openings of the variable slit; S4, for different test points in the illumination light field region, repeating the step S3 to measure different light energy values at different openings of the variable slit; and S5, storing light energy value data into a computer through a serial port communication, and performing data processing on the light energy value data by the computer to obtain the stray light of each test point on the mask surface or the silicon slice surface. The invention also provides a system for measuring the stray light.

Description

technical field [0001] The invention belongs to the technical field of modern optical testing, and relates to the accurate measurement of the stray light of a lithography illumination system and a lithography projection objective lens system and the whole-field deviation of the stray light. Background technique [0002] Stray light, also known as stray light or stray light radiation, refers to the non-imaging light radiation energy diffused on the surface of the detector in addition to the imaging light in the optical system, as well as the imaging light radiation energy reaching the detector through an abnormal optical path. . The whole field deviation of stray light refers to the deviation of stray light at different test points in the field of view. In the lithography system, it refers to the non-imaging light diffused on the mask and silicon wafer, which has a negative impact on the imaging quality and CD (Critical dimension) uniformity of the lithography pattern. [0...

AI Technical Summary

Problems solved by technology

[0010] (6) Stray light can also cause changes in the steepness of the side walls of the graphics

[0011] (7) Stray light will cause the depth of focus to decrease

Because this stray light detection method needs to make a chromium mask, the cost is extremely high, and the entire exposure process is greatly affected by the environment, which is also related to the selection of photoresist

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