The laser direct writing(LDW) system SVGLDW 04 with a projectionopticalsystem and a spatial light modulator(LCD-SLM) can expose a reduction pattern directly on a photoresist plate.
The specific parameters of main opticalsystem are deduced from the requirement of pattern transfer for the projection aligner. The limit of these parameters is discussed.
Differing from the traditional optical measuring method, the measuring system USES two CCD cameras to record projection grating, thus reduces errors and improves measuring accuracy.