X-ray lithography apparatus

Abstract

An X-ray lithography apparatus for transferring a pattern formed in a mask onto a wafer by using a soft X-ray. The apparatus comprises a soft X-ray generating unit, a gas chamber connected to an X-ray exit window of the soft X-ray generating unit and filled with a gaseous medium having a high transmittivity to the X-ray, the mask being mounted within the gas chamber, a stage for positioning the wafer in opposition to the mask with a small gap therebetween, detecting optics disposed within the gas chamber for optically picking up image of alignment patterns of the mask and wafer, an imager disposed within the gas chamber for converting the image of the alignment pattern picked up by the detecting optics into a video signal, a discharging port for withdrawing from the gas chamber the gaseous medium present in the vicinity of the imager, a combination of a blower and a heat exchanged for cooling and circulating the gaseous medium withdrawn through the gas discharging port, and a charging port for feeding back to the gas chamber the gaseous medium conditioned and circulated by the blower and the heat exchanger. The discharge port, blower and heat exchanger and the charging port cooperate to prevent the temperature of the gaseous medium within the gas chamber from being increased due to heat generated by the imager means to thereby suppress drift phenomenon in the detecting optics.