Patent ID: 8455286

Claim:
A method of forming a MEMS device, the method comprising: forming a sacrificial layer of oxide over a substrate; forming a polysilicon layer over the sacrificial layer; forming a metal layer over the polysilicon layer; forming a protection layer overlying the metal layer; etching the protection layer and the metal layer to form a contact stack structure having a remaining portion of the protection layer formed over a remaining portion of the metal layer; forming a layer of oxide over the contact stack structure and the polysilicon layer; patterning the and the layer of oxide and the polysilicon layer to form a structure of the MEMS device from the polysilicion layer and to leave a portion of the layer of oxide; etching the sacrificial layer to result in the structure of the MEMS device being movable, wherein portion of the layer of oxide is removed leaving a residue on the remaining portion of the protection layer, wherein the remaining portion of the protection layer protects the remaining portion of the metal layer during the etching of the sacrificial layer; removing the residue; and removing the remaining portion of the protection layer.