Patent ID: 7928014

Claim:
A method for manufacturing a semiconductor device, comprising an etching treatment including for each wafer the consecutive steps of: mounting a semiconductor wafer on an electrode received in a chamber of a plasma etching system, said semiconductor wafer including a first film covering a surface of said semiconductor wafer including a surface of a silicon film; dry-cleaning an internal of said chamber such that an etch selectivity of said silicon film with respect to said first film is a specific value or above; consecutively anisotropic-etching said first film and said silicon film on said wafer by using a specific plasma etching condition; and removing said semiconductor wafer from said chamber after said anisotropic etching, said method repeating said etching treatment for a plurality of wafers, wherein said dry-cleaning step applies a plasma excitation power to a coil associated with said chamber, and a bias power to said electrode, and achieves an etch selectivity of 100 or above for silicon with respect to silicon nitride, and said first film includes a silicon nitride film.