Patent ID: 6700600
Filing Date: 2004-03-02
Classification: G03F

Abstract:
A laser scanning system for microlithographic writing or inspection of patterns on a photosensitive substrate (6), the system comprising a laser light source (1) generating at least one laser light beam, a computer-controlled light modulator (3) controlled according to input pattern data, a lens to focus the light beam from the light source before it reaches the substrate, and a substrate support table to support the substrate, whereby, during the writing operation, the at least one beam is deflected across a region of the substrate surface by an acousto-optic deflector driven by a chirp frequency signal according to a set of data indicating consecutive positions of the beam on the substrate, and the substrate is moved in an oblique angel, and preferably perpendicular, to the direction of deflection to reposition it for exposure during the next stroke of the beams; and at least one sensor measuring the extent of substrate offset in the direction of deflection, characterised in that it further comprises means for modifying the position data or the feeding of the same to correspond to laterally displaced scans and a control unit for controlling said position data or the feeding of the same to read out the data to the deflector in dependence of the offset measured by the detector to compensate said offset.