| 摘要 |
PURPOSE:To equalize processing rates at various points on a wafer surface and to improve the yield of products, by controlling independently the amounts of reaction gas supplied to the central portion and to the peripheral portion on the surface of the wafer put on a wafer supporting electrode. CONSTITUTION:Reaction gas supplied from a bomb 50b is properly controlled in its flow rate by a flow controlling device 51b, and is further transmitted, through a gas feed orifice 22b, to an electrical discharge space 40, that is, the central portion on the surface of a wafer 70 put on a wafer supporting electrode 30. Reaction gas whose flow rate is properly controlled by a flow controlling device 51c is supplied via a second gas chamber 21c to the peripheral section of the wafer surface 70 through a gas feed orifice 22c. The flow rates of the reaction gas can be controlled by the flow controlling devices 51b and 51c, respectively, so as to equalize the etching rate at the central portion of the wafer surface 70 to the etching rate at the outer periphery thereof. |
