Patent ID: 7776757

Claim:
A method for fabricating a semiconductor device, comprising: providing a semiconductor substrate having a first region and a second region; forming a high-k dielectric layer over the semiconductor substrate; forming a first metal layer and a first silicon layer by an in-situ deposition process; patterning the first silicon layer to remove a portion overlying the second region; patterning the first metal layer using the patterned first silicon layer as a mask; and removing the patterned first silicon layer including applying a solution that includes: a first component having an [F-] concentration greater than 0.01M; a second component configured to adjust a pH of the solution, the pH ranging from about 4.3 to about 6.7; and a third component configured to adjust a potential of the solution, the potential being greater than −1.4 V; wherein the solution is tuned by the first, second, and third components such that an exposed portion of the high-k dielectric layer is substantially not removed during the removal of the patterned first silicon layer.