Plasma etching method and plasma etching apparatus

Abstract

The plasma etching method first forms a coating film on the inner surface of the chamber. Next, an etching process is performed on a wafer under a condition in which the coating film is formed, and thereafter a reaction product adhered onto the coating film in the etching process is removed together with the coating film. Each of these processes is implemented at a frequency in which the condition of the chamber inner surface is nearly always the same at the time of initiating the etching process.

1 - 14 . (canceled) 
   
   
       15 . A plasma etching apparatus for performing an etching process on an object to be processed by plasma maintained in a chamber, comprising:
 a coating film formation unit configured to form a coating film on the chamber inner surface;   a first gas supply unit configured to supply into the chamber a process gas used for the etching process of an object to be processed;   a second gas supply unit configured to supply into the chamber a process gas used for removal of the coating film; and wherein,   a reaction product adhered on the coating film during the etching process is removed together with the coating film by supplying a process gas by the second gas supply unit after the etching process by using a process gas supplied by the first gas supply unit is completed under the condition where the coating film is formed.   
   
   
       16 . The plasma etching apparatus according to  claim 15 , further comprising,
 the chamber comprising a dielectric wall which transmits an electromagnetic wave at the opposing position to an object to be processed;   a flat coil configured to create the induction magnetic field to maintain the plasma provided at the exterior of the chamber in response to the dielectric wall; and,   a Faraday shield electrode provided between the flat coil and the dielectric wall.