Plane grating-based system for measuring large-stroke movement of wafer bench

Abstract

A plane grating-based system for measuring large-stroke movement of a wafer bench belongs to the technical field of ultra-precision measurement. The system comprises a plane grating and a reading head array. The plane grating is installed on the lower surface of a moving bench of the wafer bench, and the reading head array is installed on a fixed bench. Each reading head can measure displacements of the moving bench of two directions. At any time, the plane grating is covered by three or more reading heads from under the plane grating. Therefore, when the moving bench of the wafer bench makes any large-stroke movement, the displacement of the moving bench can be measured through reading head switching. The system uses the two-dimensional high-precision plane grating as a measurement element, and the multiple reading heads are arranged in the movement region of the wafer bench, so that the measurement requirements of large-stroke movement of the wafer bench are satisfied. The measurement optical paths between the reading heads and the plane grating are short, and errors induced by the environment are small. Meanwhile, the plane grating is arranged on the moving bench, so that cable disturbance to wafer bench movement caused by the system is prevented.

Description

technical field [0001] The invention relates to a six-degree-of-freedom large-stroke motion measurement system for a silicon wafer stage, in particular to a high-precision measurement scheme for large-stroke planar motion, which is mainly used in semiconductor processing and manufacturing and testing equipment, and belongs to the technical field of ultra-precision measurement. Background technique [0002] In the lithography machine system, the silicon wafer stage is used to carry the silicon wafer for step and scan movement. The productivity and overlay accuracy of the lithography machine determine the high-speed, high-acceleration, large-stroke and ultra-precision movement characteristics of the wafer stage. At present, optical measurement method, inductance measurement method and capacitance measurement method are mainly used to measure the plane motion of silicon wafer stage. Optical measurement method is relatively mature in ultra-precision measurement and is currently ...

AI Technical Summary

Problems solved by technology

However, the movement range of the wafer stage in this scheme is limited by the arrangement of the reading heads, that is, the measurement system can work normally only when the grating on the wafer stage is below the array of reading heads arranged orthogonally

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