Method for dry etching Al
View Patent ↗The invention provides a dry etching method for processing a wafer having an Ru film formed on a thick Al 2 O 3 film to be used for a magnetic head, capable of realizing high selectivity. In the etching of a wafer having disposed on an NiCr film 15 an Al 2 O 3 film 14 , an Ru film 13 , an SiO 2 film 12 and a resist mask 11 , the Ru film 13 is etched via plasma using a processing gas containing Cl 2 and O 2 (FIG. 1 ( c )), and thereafter, the Ru film 13 is used as a mask to etch the Al 2 O 3 film 14 via plasma using a gas mixture mainly containing BCl 3 and also containing Cl 2 and Ar (FIG. 1 ( d )).
1. 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.
2. The method for dry etching an Al 2 O 3 film according to claim 1 , wherein the etched ruthenium film is the patterned ruthenium film used in providing the mask for dry etching the Al 2 O 3 film.