| 摘要 |
<p>A known projection aligner for integrated circuit fabrication, in which an integrated circuit pattern image is projected on a wafer, comprises an ArF excimer laser (1) and an optical system (5) comprising three groups of quartz glass optical members made of synthetic quartz glass. To provide a projection aligner having optical properties, such as transmittance, which are not degraded over a long time of operation and so that the optical system can be constructed at a low cost as a whole, it is suggested that the first quartz glass optical member group which is subjected to relatively low energy densities has a hydrogen molecule concentration in the range between 1 x 1017 and 5 x 1018 molecules/cm3 and that the third quartz glass optical member group (5a, 5b) which is subjected to relatively high energy densities has a hydrogen molecule concentration in the range between 5 x 1018 to 5 x 1019 molecules/cm3.</p> |
