Patent ID: 7541270

Claim:
A method of forming a self-aligned contact hole, comprising: providing a pair of gate stacks in spaced relation to one another on a semiconductor substrate, wherein: each of said gate stacks has at least one conductive layer formed therein and an insulating layer extending over said conductive layer; said insulating layer is selected from undoped silicon dioxide and silicon nitride and combinations thereof; and a contact area is defined on said semiconductor substrate between said pair of gate stacks; forming a spacer composed of a spacer material adjacent to each side of said gate stacks, wherein said spacer material is selected from undoped silicon dioxide and silicon nitride and combinations thereof; forming a doped silicon dioxide layer over said pair of gate stacks and over said contact area; forming a patterned layer on said doped silicon dioxide layer, wherein said patterned layer exposes the doped silicon dioxide overlying said contact area; and etching a self-aligned contact hole through doped silicon dioxide exposed by said patterned layer in a plasma processing chamber, wherein said step of etching a contact hole comprises; flowing an etchant gas mixture consisting essentially of at least one fluorocarbon gas, at least one hydrogen containing gas, said hydrogen containing gas excluding any gas containing a fluorine species, and at least one inert gas into said plasma processing chamber; striking a plasma in said plasma processing chamber from said etchant gas mixture; and utilizing said plasma to etch said contact hole in said doped silicon dioxide layer, said etch being relatively highly selective of said doped silicon dioxide layer and relatively minimally selective of said insulating layer and said spacer material, and said self-aligned contact hole extending to said contact area.