Patent ID: 6067165
Filing Date: 2000-05-23
Classification: G01B

Abstract:
A position calibrating method for a plurality of optical length measuring devices in an optical measuring apparatus configured with said plurality of the optical length measuring devices supported to be three-dimensionally driven relative to a stage on which a workpiece may be mounted, comprising the steps of:preparing a calibration jig defining a reference pattern with which position measurement is possible in a horizontal plane by each optical measuring device formed on a base plate and mounting said calibration jig on the stage;measuring a coordinate of the reference pattern of the calibration jig with each of the optical length measuring devices;subjecting a coordinate value of the reference pattern obtained by each of the optical length measuring devices to an arithmetic operation to calculate an offset value in the horizontal plane between the respective optical length measuring devices; andusing the thus-obtained offset value as position calibration data for each of the optical length measuring devices to perform position calibration of the measurement data subsequently gathered by each of the optical length measuring devices.