Patent ID: 8350337

Claim:
A method of forming a semiconductor device, comprising: providing a substrate having a first area and a second area; forming a first stacked pattern comprising a first dielectric layer and a first polysilicon layer in the first area, and forming a second stacked pattern comprising a second dielectric layer and a second polysilicon layer in the second area, wherein the first polysilicon layer and the second dielectric layer have a same thickness; thinning the second polysilicon layer to obtain a thinned second polysilicon layer; forming an interlayer dielectric layer on the substrate; performing a planarization process, so as to remove a portion of the interlayer dielectric layer until a surface of the first stacked pattern in the first area is exposed; removing the exposed first stacked pattern in the first area to form an opening; and forming a metal gate in the opening, wherein the thinned second polysilicon layer has a height less than that of the metal gate.