Deep UV exposure of Ag2Se/GeSe2utilizing an excimer laser

Although inorganic resists are characterized by high contrast and resolution, they have traditionally suffered from poor sensitivity. We have investigated the use of a rare-gas halide excimer laser operating at λ = 249 nm to expose the inorganic resist Ag2Se/GeSe2. Well-controlled lines and spaces, each of 0.5-µm width, were contact printed using a chromium-on-quartz mask. By increasing the peak dose rate to about 520 kW/cm², we found that the required dose could be lowered from 130 to 5.2 mJ/cm²; this sensitivity is a factor of 250 better than that obtained with exposures at λ = 436 nm and low power densities. The reciprocity failure at these high flux rates can be explained by a locally induced temperature rise.