Hybrid optical measurement system for evaluation of precision two-dimensional planar stages
Jong-Ahn Kim, Jae Yong Lee, Chu-Shik Kang, Jae Heun Woo
Abstract
This paper presents an optical measurement system, which is mainly composed of two hybrid sensor modules (HSMs), for evaluation of precision two-dimensional (2D) planar stages. The HSM is designed to integrate two different types of sensors within a single sensor module, so that it can be operated as a profile interferometer or an angle sensor by simply switching the data-processing mode. This enables us to implement efficient on-site evaluation of straightness errors of moving mirrors of a two-axis laser interferometer, and multi-axis parasitic motion errors of a 2D planar stage without reconfiguration of the evaluation setup. To estimate the performance of a prototype measurement system, an exemplary 2D stage was experimentally evaluated, and the straightness and angular motion errors were measured with expanded uncertainty (k = 2) of 40 nm and 0.14″, respectively. Reliability of the measurement system was also verified by comparison with reference instruments.