摘要 |
An improved lithographic interferometer system, is presented herein. The lithographic interferometer system comprises a beam generating mechanism, mirrors which reflect those beams, and detection devices for detecting an interference pattern of overlapping reflected beams. The beam generating mechanism comprises a beam-splitter, which splits the beams into reference beams and measuring beams, a reference mirror that provides a plane mirror interferometer, and a reflective surface that emits at least one reference beam used in a differential plane mirror interferometer.
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