Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.