Abstract: In a system for locating and measuring an index mark on an edge of a wafer, a wafer to be examined is positioned and centered on a chuck in a horizontal chuck position such that an index mark is oriented within first and second index mark orientation features disposed on the chuck. The chuck is translatable, tiltable between horizontal and vertical positions, and rotatable over an angle subtended by the index mark orientation features of the chuck. A laser beam from a laser beam optical profiler is focussed on the surface of the wafer at a distance proximate the wafer edge and proximate the first index mark orientation feature of the chuck. The chuck is rotated in a direction from the first to the second index mark orientation feature whereby a reflected portion of the laser beam generates data corresponding to the angular location of index mark edges. An index mark center location is computed.

Abstract: A fully automated surface profiling system having a loading chamber and an adjacent measurement chamber containing a phase differential laser optical scanning system and a five-axis positioner having a vacuum chuck for holding and orienting a wafer for surface profile measurement. The positioner can displace a mounted wafer lengthwise and crosswise of the chamber, can rotate the wafer about vertical and horizontal axes through the positioner, and can rotate the wafer about its own axis. Each motion is motor-driven and can be carried out independently of all the others or in compound motion as needed. The positioner can accommodate a series of replaceable chucks for holding wafers of different diameters. The loading chamber has a cassette dock for receiving a cassette containing wafers to be tested, a robotic server, and a prealigner. All operations within the profilometer are controlled by a programmable CPU at a control station.