A two-dimensional displacement measurement device using a dual-frequency laser and a diffraction grating

Abstract

The invention discloses a two dimension displacement measurement device which uses a double frequency laser and a diffraction grating, and relates to an ultra precise displacement measurement technology and an optical grating displacement measurement system. The two dimension displacement measurement device which uses the double frequency laser and the diffraction grating is composed of a scale grating and a reading head, wherein the reading head comprises a double frequency laser light source, a Z direction interference component, a scan light splitting grating component, an X direction detection component, a Z direction detection component and a signal processing component. The two dimension displacement measurement device which uses the double frequency laser and the diffraction grating is based on a Michelson interferometer theory, a multiple diffraction grating interference theory and an optics beat frequency theory, can achieve simultaneous measurement for X direction displacement and Z direction displacement, has the advantages of being compact in structure, strong in interference resisting ability, and low in demand for backward zero order diffraction intensity of the scale grating, decoupling the X direction measurement and the Z direction measurement and the like, can achieve nanometer level or even higher lelvel measurement resolution, and can be used in displacement measurement multiple in freedom degree and high in accuracy.

Description

technical field [0001] The invention relates to an ultra-precise displacement measurement technology and a grating displacement measurement system, in particular to a two-dimensional displacement measurement device using a dual-frequency laser and a diffraction grating. Background technique [0002] In recent years, ultra-precision measurement has become a research hotspot in the field of measurement in the world. Considering the influence of factors such as measurement range, accuracy, system size, and working environment, the demand for high-precision measurement using a small-volume multi-degree-of-freedom measurement method is becoming more and more prominent in modern displacement measurement. In the field of semiconductor processing, the positioning accuracy and motion accuracy of the mask table and workpiece table in the lithography machine are the main factors that limit the line width of semiconductor chip processing. In order to ensure the positioning accuracy and ...

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Problems solved by technology

In this group of patents, when the reading head moves in the Z direction relative to the scale grating, the range of the interference area becomes smaller, which is not conducive to the measurement of a larger range in the Z direction

[0008] The patents CN102865817A (disclosure date January 9, 2013) and US8604413B2 (disclosure date December 10, 2013) of Mitutoyo Corporation of Japan propose a structure of a two-dimensional displacement sensor, which can realize multidimensional displacement measurement, but The whole system adopts the transmission method, and uses optical devices such as prisms for refraction, so the system is relatively large

[0009] In the patent CN103604376A (published on February 26, 2014) by Hu Pengcheng, a scholar of Harbin Institute of Technology, a kind of anti-optical frequency aliasing grating interferometer system is proposed, and the dual-frequency laser emitted by the laser is transmitted separately in space. setting, eliminating the optical frequency aliasing and the corresponding periodic nonlinear error, and can realize the measurement of three-dimensional displacement; in the patent CN103644849A (disclosure date March 19, 2014) of Harbin Institute of Technology scholar Lin Jie et al., by introducing the self The principle of collimation proposes a three-dimensional displacement measurement system, which can achieve a large range of Z-direction displacement measurement, but due to the large number of beam splitting times, it is not conducive to improving the quality of the interference signal

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