Double frequency laser grating interference two-dimensional measurement method and system with optical aliasing resistance

Abstract

The invention discloses a double frequency laser grating interference two-dimensional measurement method and system with optical aliasing resistance, and belongs to a grating measurement technology. The system comprises a laser device, a grating interference mirror set and a photoelectric detection and signal processing unit. Two laser beams which are simultaneously output by the laser device, different in frequency and separated in space enter a polarizing beam splitter in parallel and in an incident mode. The first laser beam enters a reference grating in an incident mode after being reflected by the polarizing beam splitter to form multiple reference diffraction laser beams with multiple levels, the second laser beam enters a measurement grating in an incident mode after being transmitted by the polarizing beam splitter to form multiple measurement diffraction laser beams, three of the reference diffraction laser beams are sequentially and correspondingly joint with the 0 laser beam, the +1 laser beam and the -1 laser beam in the measurement diffraction laser beams respectively to form an optical beat frequency, and two-dimensional relative motion information of the measurement grating is acquired through photoelectric detection and signal processing. By the adoption of the method and system, optical frequency aliasing, polarization state aliasing and corresponding periodic non-linear errors caused by traditional incomplete polarizing beam splitting are eliminated, and combination properties of a photoetching machine ultra-precise workpiece table position measurement system can be improved when the double frequency laser grating interference two-dimensional measurement system is used for the photoetching machine ultra-precise workpiece table position measurement system.

Description

technical field

[0001] The invention relates to a grating measurement method and a measurement system, in particular to a dual-frequency laser grating interference two-dimensional measurement method and a measurement system. Background technique

[0002] The lithography machine in semiconductor manufacturing equipment is the key equipment in the production of semiconductor chips. The ultra-precision workpiece stage is the core subsystem of the lithography machine, which is used to carry the mask plate and silicon wafer to complete the high-speed ultra-precision step-and-scan movement. Ultra-precision workpiece table has become the most representative type of ultra-precision motion system due to its high-speed, high-acceleration, large-stroke, ultra-precision, and multi-degree-of-freedom motion characteristics. In order to realize the above-mentioned movement, the ultra-precision workpiece table usually uses a dual-frequency laser interferometer measurement system to measure...

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