| 摘要 |
PURPOSE:To make it possible to reduce a surface film consisting of such an oxide and a nitride as silicon dioxide by a method wherein the laser producing plasma of such gas as to contain at least one or both of hydrogen and a halogen element is produced and the plasma is irradiated on the surface of a semiconductor metal substrate. CONSTITUTION:A 248-nm wavelength laser beam 22, which is generated trom a Kr F pulsed excimer laser 21 is introduced into a vacuum container 25 through a 50-cm focal length convex lens 23 consisting of fused quartz and a window 24. The air in the container 25 is evacuated by a vacuum exhaust pump 26 and the degree of vacuum in the container 25 is held at 1X10<-2> Torr by making hydrogen gas 27 flow through a gas leakage valve. The repetitive frequency of laser pulse is set as 10 Hz and an Si substrate 28 is exposed to hydrogen plasma for about 10 seconds. By this plasma irradiation, a natural oxide film on the surface of the substrate 28 is removed. In such a way, by irradiating the plasma having a reducing action chemically to reduce the coated layer on the treated substrate surface, the natural oxide film is reduced and can be removed in a short time and also, holding the temperature of the substrate at low temperature.
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