Patent ID: 7754613

Claim:
A method of etching a silicon substrate loaded onto a platform within a processing chamber, the etching method comprising: (a) an etching operation of in a state in which gas within the processing chamber has been exhausted to pump down the chamber interior, supplying etching gas into the processing chamber and converting the etching gas into plasma, and meanwhile applying a bias potential to the platform, to etch the silicon substrate, halting the supply of etching gas when a preestablished time prior to the close of said etching operation is reached, and making the exhaust flow rate at which gas is exhausted from inside the processing chamber, from when the preestablished time is passed up until the close of said etching operation, greater than the exhaust flow rate prior to when the preestablished time is passed; (b) a protective-film deposition operation of in a state in which gas within the processing chamber has been exhausted to pump down the chamber interior supplying protective-film deposition gas into the processing chamber and converting the protective-film deposition gas into plasma, to form a protective film onto the silicon substrate; a step of halting the supply of protective-film deposition gas when a preestablished time prior to the close of said protective-film deposition operation is reached, making the exhaust flow rate at which gas is exhausted from inside the processing chamber, from when the preestablished time is passed up until the close of said protective-film deposition operation, greater than the exhaust flow rate prior to when the preestablished time is passed; and in alternation repeating said operations (a) and (b).