Inscribing apparatus and methods

摘要

Apparatus and methods for inscribing workpieces for the fabrication of masks and direct fabrication of microcircuits are described. The invention is primarily concerned with correcting for positional errors and to this end two coaxial beams (20,32) are directed towards a worktable from opposite sides thereof, the beam (20) serving as the scribing beam and the beam (32), operating in a reading mode, serving to read positional information and generate positional information and appropriate error signals for correcting the point of impact of the beam (20) with the surface of the substrate to be inscribed (28,46). In one embodiment the table (10) is solid and two layers of substrate are used on opposite surfaces of the table (10). The lower substrate (30) constitutes a master substrate which can be left in position while a large number of virgin substrates are exposed on the upper surface of the table (10). In another embodiment the table (44) is in the form of a frame for peripherally supporting a wafer on substrate workpiece (46) so that both upper and lower surfaces of the wafer are exposed to the two electron beams, the underside surface constituting the registration surface. Marks are formed therein by scribing the surface using the beam (32).