POSITION DETECTION SYSTEM USING LASER LIGHT INTERFEROMETRY

According to the disclosure, a position detection system using laser light interferometry is proposed, capable of measuring the positions and displacements of an object relative to and within an XYZ system of coordinates, the system using a holder comprising a mounting surface for the object, the mounting surface being oriented in the XY plane of the XYZ system of coordinates, several X, Y and Z measuring mirrors as well as a plurality of X, Y, and Z optical devices, each optical device structured to emit and direct an X, Y or Z laser light beam to and from a respective X, Y or Z measuring mirror and structured to detect and convert at least part of the X, Y or Z laser light beams reflected by the respective X, Y or Z measuring mirrors into electric measuring signals, the electric measuring signals comprising at least information as to the X, Y and Z position of the object, wherein, for measuring the Z position of the object, the at least one Y laser light beam is directed parallel to the XY plane to and from a Y measuring mirror positioned perpendicular to the XY plane and the at least one Z laser light beam is directed under an angle a relative to the XY plane to and from a Z measuring mirror. By directing the Y laser light beam parallel to the XY plane to and from a Y measuring mirror positioned perpendicular to the XY plane and directing the Z laser light beam under an angle a relative to the XY plane to and from a Z measuring mirror, the optics of the position detection system can be simplified as any additional Z measuring mirror can be obviated. Particularly, this results in less occupied work volume in the direct vicinity where semiconductor and integrated circuit manufacturing processes.