Universal edged-based wafer alignment apparatus

摘要

An apparatus for aligning a wafer. The edge of a wafer is mapped by means of a photodetector array and a light source to provide a signal representative of the X-Y position and angular orientation of the wafer as the wafer is rotated one revolution on a shaft. The signal is digitized and processed to provide stored information of the X-Y position and angular orientation of the wafer. The shaft is then rotated to move the wafer from its calculated angular orientation to a desired angular orientation. The X-Y positional information may be used to center the wafer.