| 摘要 |
PURPOSE:To enable the formation of an accurate reduced pattern on a semiconductor wafer by supplying an mixed gas into a lens system and forming a pattern while exhausting said gas so as to enable the wide-range correction of magnification as well as to cool lenses by the mixed gas. CONSTITUTION:a mask on which a predetermined pattern is formed is attached above a lens system 1 composed of plural lenses 2a... 2n and a semiconductor wafer coated with a resist is put under this lens system. Consequently, after a light from a light source passes the mask, it is reduced by the lens system 1 and a reduced pattern is formed on the semiconductor wafer. By a gas mixing device 6 arranged on the upstream side of an inlet 4 opened on a side plane of an enclosure of the lens system 1, a gas and the air mixed and it is supplied into the lens system 1. Also, the mixed gas supplied into the lens system 1 is exhausted from an outlet 5. As the gas for use, a gas whose refractive index is different from that of the air and which does not have a bad influence on the lens system 1 is used. Thus a refractive index can be modulated and the wide-range correction of magnification can be made by varying a mixing ratio arbitrarily.
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