PROCESSING APPARATUS

A processing apparatus includes a chamber having a gas inlet and a gas outlet; a plasma generator; and a controller configured to cause: (a) etching a silicon-containing film to a first depth with a first plasma in the chamber, thereby forming a recess in the silicon-containing film; (b) forming a protection film on a side wall of the recess with a second plasma in the chamber, the protection film having a first thickness at an upper portion of the recess and a second thickness at a lower portion of the recess, the second thickness being smaller than the first thickness; and (c) etching the silicon-containing film to a second depth with the third plasma in the chamber, the second depth being greater than the first depth.