PLASMA TREATER

PURPOSE:To rationalize the distribution of flow of a treating gas to a sample treating surface, and to ensure film-formation treatment or plasma etching by selecting the position of a gas discharge hole discharging the treating gas at an arbitrary position in the radial direction. CONSTITUTION:A gas chamber 67 is mounted to the lower surface of an upper electrode 60 of a pair of vertically opposite opposite electrodes 60 installed in a treating chamber 10, and a rotatable gas discharge plate 66 with a plurality of gas discharge ports 69a-69c and a shutter plate 65 to which a slit 70 is shaped are disposed to the base of the gas chamber 67. Through-holes are bored to the outer wall of the treating chamber 10 and a fixed plate 62 covering the upper surface of the gas chamber 67, a hollow shaft 61 connected to a gas supply pipe 40 is inserted into the through-holes, and the lower end of the hollow shaft 61 is opened previously into the gas chamber 67. The treating chamber 10 is constituted in this manner, and a supply gas is fed into the gas chamber 67 through the supply pipe 40 and a flow path 63, but the discharge plate 66 is turned through a shaft 64 for the hollow shaft 61 and an optimum hole in the discharge holes 69a-69c is conformed to the slit 70 when the distribution of a gas flow and water is inadequate to a sample surface at that time.