Patent ID: 8506834

Claim:
A method for dry etching an Al 2 O 3 film which has a thickness of 200 nm to 1,000 nm, and is arranged on a nickel chrome alloy film of a sample having a ruthenium film arranged on the Al 2 O 3 film, comprising the steps of: dry etching the ruthenium film using a gas mixture containing Cl 2 O 2 and Ar, so as to form an etched ruthenium film; and dry etching the Al 2 O 3 film, using a gas mixture containing BCl 3 , Cl 2 and Ar, so as to form at etched Al 2 O 3 film, wherein the ruthenium film is dry etched using a patterned silicon oxide film and a patterned resist film as a mask, so as to form the etched ruthenium film; and wherein the Al 2 O 3 film is dry etched using a patterned ruthenium film and the patterned silicon oxide film as a mask, so as to form the etched Al 2 O 3 film.