VACUUM ULTRAVIOLET-RAY LITHOGRAPHY DEVICE, ITS MANUFACTURE, AND METHOD FOR INSPECTING CRYSTALLINE FLUORIDE MATERIAL

摘要

PROBLEM TO BE SOLVED: To predict degradation quantity in transmittance of a plurality of crystalline fluoride materials caused by vacuum ultraviolet rays, by classifying the fluoride crystal materials based on the degradation quantity in transmittance of the materials caused by ArF excimer laser light, and arranging the classified materials in accordance with the fluence of the light projected upon each optical member.;SOLUTION: The deteriorated transmittance amounts of three kinds of calcium fluoride crystals containing an impurity at different concentrations are measured by projecting ArF excimer laser light upon each crystal. The laser light is projected by 10,000 pulses under the condition of 100 mJ/cm2/pulse in fluence and the transmittance variation of the crystals at 193 nm is measured by using a spectrophotometer. For another three kinds of samples, the transmittance variation of the samples at 157 nm is measured by projecting F2 laser light upon each sample. Then the correlations between the degradation quantity in transmittance at 193 nm caused by the ArF excimer laser light and those at 157 nm caused by the F2 laser light are found, so that the degradation quantity in transmittance of the calcium fluoride crystals may be predicted from the degradation quantity in transmittance of the crystals at 193 nm.;COPYRIGHT: (C)2001,JPO