Pattern generation system

摘要

An improved pattern generation system. The pattern generation system of the present invention discloses an improved optical system for correcting problems of astigmatism and ellipticity in a radiant energy beam used for generating patterns on a workpiece. The present invention further discloses improved control circuitry for controlling modulation of said beams. The control circuitry corrects for problems of isofocal bias caused by non-linearities in the turn-on/turn-off of the beams.