System wave aberration detection method capable of calibrating system errors

Abstract

The invention provides a system wave aberration detection method capable of calibrating system errors. The system wave aberration of a projection objective to be detected is subtracted from the system errors of a shear interference detection system to obtain the actual wave aberration of the projection objective to be detected, the influence of the system errors is eliminated, and measuring accuracy is improved. A filtering function can be achieved by a small hole space filter, aberration caused by a lighting system and a first convergence lens can be eliminated, and detection accuracy of the system wave aberration is improved. Only +/- level diffraction light can pass a window in the space filter, zero and higher level diffraction light is intercepted by the space filter, so that noise is reduced, and measuring precision is improved.

Description

technical field [0001] The invention relates to the technical field of optical detection, in particular to a system wave aberration detection method capable of calibrating system errors. Background technique [0002] Optical projection lithography is an optical exposure process that uses the principle of optical projection imaging to transfer the high-resolution IC pattern on the mask to the rubber-coated silicon wafer by exposure. It is the most widely used in the manufacturing process of VLSI The lithography technology with the widest and fastest technological progress. The lithography process directly determines the feature size of large-scale integrated circuits and is a key process in the manufacture of large-scale integrated circuits. The projection objective lens of a lithography machine is the core component of the lithography process and the most difficult subsystem. [0003] After years of development, the exposure wavelength of the lithography machine has develop...

AI Technical Summary

Problems solved by technology

However, this method has strict requirements on the technical indicators such as eccentricity and tilt during the rotation process of the projection objective lens under test. Therefore, not only a rotating mechanism with strong load-bearing capacity is required, but the rotating mechanism also requires extremely high positioning accuracy and repeatability. , which is very difficult to realize in engineering

And the method of separating systematic errors by rotating the projection objective under test has significant limitations for high NA projection objectives using mirrors and off-axis optics

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