Alternative method for advanced CMOS logic gate etch applications

Methods for etching, such as for fabricating a CMOS logic gate are provided herein. In some embodiments, a method of etching includes (a) providing a substrate having a first stack and a second stack disposed thereupon, the first stack comprising a high-k dielectric layer, a metal layer formed over the high-k dielectric layer, and a first polysilicon layer formed over the metal layer, the second stack comprising a second polysilicon layer, wherein the first and second stacks are substantially equal in thickness; (b) simultaneously etching a first feature in the first polysilicon layer and a second feature in the second polysilicon layer until the metal layer in the first stack is exposed; (c) simultaneously etching the metal layer and second polysilicon layer to extend the respective first and second features into the first and second stacks; and (d) etching the high-k dielectric layer.