| 摘要 |
PURPOSE:To increase transmission factor of X-ray, by a method wherein excessive gas is exhausted by injecting hydrogen or helium gas little by little. CONSTITUTION:An X-ray take-out tube 8 has an X-ray transmitting window 7 in the side near by an X-ray source 2, an X-ray transmitting window 21 in the side near by a combination 15 of mask and wafer, a gas exhaust hole 22 near by the end in the side of the X-ray transmitting window 21, and a gas introducing means 20 near by the X-ray transmitting window 7. The X-ray take-out tube 8 is provided with a flange 4, and is fixed to a vacuum chamber 1 through a O- ring 5. When hydrogen or helium gas is introduced to the X-ray take-out tube 8 by the pressure little higher than the atmospheric pressure, the mixture of said gas with air is exhausted from the gas exhaust hole 22. As specific gravity of hydrogen or helium gas is less than that of the air, the air within the tube 8 is gradually replaced by said hydrogen or helium gas, and the X-ray take out tube 8 is filled with high-purity hydrogen or helium. |
