Patent ID: 8257609

Claim:
An etchant simultaneously etching at least two different metal layers, comprises hydrogen peroxide (H 2 O 2 ), fluorine (F) and one of carboxylate salt of sodium acetate (CH 3 COONa), and acetyl group (CH 3 CO—), wherein the fluorine (F) has a concentration of about 0.1 wt % or more, wherein the carboxylate salt of sodium acetate has a concentration of about 0.5 wt % or more, and the hydrogen peroxide (H 2 O 2 ) has a concentration of about 0.1 mol or more, and wherein the acetyl group (CH 3 CO—) includes one of ammonium pivalate ((CH 3 ) 3 C 2 OONH 4 ), sodium pivalate ((CH 3 ) 3 C 2 OONa), and potassium pivalate ((CH 3 ) 3 C 2 OOK).