Patent ID: 6357996
Filing Date: 2002-03-19
Classification: H01L

Abstract:
An apparatus for rotating a substantially planar, generally circular specimen having an effective center and a major surface with a periphery, the major surface including a work area and an exclusion zone extending outwardly of the work area to the periphery, comprising:a frame, multiple capstans mounted to the frame to support the specimen and rotate about different capstan axes relative to the frame, the multiple capstans mutually spaced apart at locations to receive and support the specimen by contact outwardly of the work area, and each of the capstans having a specimen receiving surface that when in contact with the specimen grips the specimen as the capstan rotates about its capstan axis; a drive mechanism that is common to all of the multiple capstans and includes a motor and a linkage mechanism, the motor imparting rotational motion to a shaft, and the linkage mechanism operatively coupled to the shaft and each of the multiple capstans to drive them in synchronous rotation about their respective capstan axes and thereby rotate the specimen without slippage between each of the multiple capstans and the specimen as it rotates through actual rotational angles; a rotary position detector operatively coupled to the shaft to track its rotational position; and a specimen peripheral edge sensing device operatively associated with the specimen to sense and provide a reference signal indicative of a reference location of the specimen as it rotates about its effective center, the rotary position detector operatively linked with the edge sensing device to respond to the reference signal to synchronize tracking of the rotation of the specimen and the rotation of the shaft and thereby provide an indication of the actual rotational angles of the specimen.