Patent ID: 6020964
Filing Date: 2000-02-01
Classification: G03F

Abstract:
An interferometer system for measuring position and displacement of an object in a plane parallel to the XY plane of an XYZ system of co-ordinates using X and Y measuring mirrors which are arranged on a holder for said object, said system comprising:a means for generating a plurality of measuring beams and for directing said measuring beams along a plurality of measuring axes which are parallel to the XY plane and extend to and from said measuring mirrors; anda plurality of radiation-sensitive detectors which convert measuring beams reflected by said measuring mirrors into electric measuring signals, wherein a number of X and Y measuring axes is at least equal to a number of object movements to be measured interferometrically,wherein said system is adapted to measure a Z position of said object using a Z measuring mirror arranged on said holder of said object at an acute angle to the XY plane, and the interferometer system includes a Z measuring axis and a means for generating a Z measuring beam and for directing said Z measuring beam onto said Z measuring mirror, and a Z detector which converts said Z measuring beam from said Z measuring mirror into a signal containing information about said Z position of said object.