Bell Telephone Laboratories

Victor Andrew Firtion

Thomas Edward Saunders

Leif Rongved

Martin E Poulsen

Donald R Herriott

Kevin James Brady

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.

Apparatus and method for holding and planarizing thin workpieces

Integrated circuit mask patterns are laser machined by mounting substrates on a support that is periodically stepped in a y direction after each scan by a laser writing beam in an x direction. X-direction scanning is accomplished by mounting a mirror on a carriage that reciprocates by rebounding between two displaced coil springs. A coding laser beam is reflected from the carriage through a stationary code plate, comprising alternate transparent and opaque stripes, to monitor the position of the carriage and to control the modulation of the writing beam.

Pattern generating apparatus

A table is reciprocated along a straight line by a force that does not precisely control movement direction. Accurate motion constraint is provided by two separated air bearings arranged along a common axis. A third air bearing, displaced from the common axis, supports the table on a sleeve that is free to rotate on its axis.

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Secaucus, NJ, United States of America

Victor Andrew Firtion