Position measuring apparatus

Abstract

A position measuring apparatus for an alignment of an array of devices such as a thin film magnetic heads on a semiconductor wafer with a high degree of accuracy and satisfactory reproducibility, comprising, on a base, an object holding unit on which an object to be measured, an X-stage, a portal sub-base arranged across over the X-stage, a Y-stage arranged on the portal sub-base, a TV microscope (detector) capable of movement in a Z-axial direction, a ball circulation type linear guide and a motor for driving and guiding the X-stage and the Y-stage, an X-axial straight bar and a Y-axial straight bar attached to side surfaces of the object holding unit, and triangulation type laser displacement meters arranged in the vicinity of and in opposite to the X-axial bar and Y-axial bar, for detecting lateral motion errors during straight movement of the holding unit in the X- and Y-axial direction with a high degree of accuracy.