SURFACE TREATMENT APPARATUS

PURPOSE:To facilitate the control of the flow distribution of gas by a method wherein, with the back space of a gas dispersing plate provided in a treating tank divided into a plurality of small spaces by partition walls, plural pieces of gas flow rate control units are provided outside of the treating tank and the small spaces and the gas flow rate control units are interconnected through piping. CONSTITUTION:A process gas (a) fed from a gas source is led to flow rate control units 9a, 9b and 9c through a piping 11. The flow rate control units 9a, 9b and 9c are adjusted in such a way that the total gas flow rate to be fed in a treating tank 1 is set at the prescribed rate and also, the gas flow rate to be fed in spaces A, B and C is the desired rate. Hereby the distributed process gases are fed to a wafer 14 and its vicinity through gas blowoff holes 12 of a gas dispersing plate 6. When a high-frequency power is impressed on a lower electrode 2 from a power source 4, the process gases fed between the lower electrode 2 and an upper electrode 5 are brought into a plasmatic state by discharge and the surface of the wafer 14 is etched. Thereby, a high uniformity can be easily obtained in the treatment of the wafer.