Abstract: A method of fabricating a gate stack having an endpoint detect layer and a multi-step etch process to prevent damage to a gate dielectric layer. The special endpoint detect layer emits an endpoint signal that allows the etch chemistry to be changed to a more selective polysilicon to oxide ratio to prevent damage to the gate oxide layer. The invention begins by forming a gate dielectric layer over a substrate. We then form an endpoint detect layer over the gate dielectric layer. A gate stack is formed over the bottom silicon layer. Then a mask is formed over the gate stack. The mask defines a gate electrode. We etch the gate stack and the endpoint detect layer using a multi-step etch comprising at least 3 steps. In a main etch step, the gate stack and the endpoint detect layer are etched using a first etch chemistry. Upon an endpoint detection signal generated by etching the gate stack, the first etch step is stopped.