Bell Telephone Laboratories

Donald R Herriott

Leif Rongved

Martin E Poulsen

Victor Andrew Firtion

Thomas Edward Saunders

An apparatus and method for holding a thin workpiece such as a semiconductor wafer for operations which require the workpiece to have a high degree of planarity such as photolithographic printing includes positioning the workpiece onto a planar holding face comprising the points of a multiplicity of regularly spaced-apart substantially parallel pins with a thin rim encompassing all pins to contain a vacuum in the region adjacent to the workpiece. The small abutting area of each pinpoint abutment reduces the probability of dirt particles collecting on the holding face and provides a high thrust pressure to dislodge dirt particles interposed between the abutment and the workpiece. A small amount of lateral motion is imparted to the workpiece when it first contacts the holding face to brush off any dirt particles on the abutments.

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Morris Township, NJ, United States of America

Donald R Herriott