Performance Evaluation and Improvement of a Dual- frequency Laser Interferometer for Nano Positioning Stage

摘要

With advances of technologies in fields of IC manufacturing, positioning and measuring accuracy of ultra-precision machining and precision instruments is getting higher and higher. The combination of high resolution and outstanding accuracy has made high performance laser interferometer an ideal choice for IC photolithography. But testing and evaluation of an interferometer system is very difficult, because it can be easily affected by pressure, vibration and temperature. How to analyze a system error, and which error sources can be minimized or eliminated are discussed. A method to test and evaluate the performance of interferometer system is proposed. To conduct the test and evaluation, an experiment system of macro-micro actuators based long stroke nano-positioning stage is provided, and it is made up of a coarse stage covering long range up to an accuracy of a few micrometers, as well as a fine stage covering small range at nano-accuracy. And with an appropriate dual servo control loop algorithm implemented to link the stages, it can give nanometer accuracy over the long range of motion. Based on that, corresponding experiments under standstill circumstance, uniform motion as well as long time evaluation are carried out, and the correctness and effectiveness of the high performance interferometer research are validated.