Patent ID: 7060629

Claim:
A method of fabricating silicon nitride features on an integrated circuit device comprising: providing a semiconductor substrate assembly comprising: first and second vertically-oriented integrated circuit structures, each having a horizontally-oriented surface and a vertically-oriented surface, wherein the first and second integrated circuit structures are horizontally spaced from each other; and a horizontally-oriented base surface interposed between the first and second integrated circuit structures; forming a layer of silicon nitride over the horizontally-oriented surfaces and over the vertically-oriented surfaces of the first and second integrated circuit structures such that the horizontally-oriented and vertically-oriented surfaces of first and second integrated circuit structures and the horizontally-oriented base surface between the integrated circuit structures are covered with the layer of silicon nitride; and anisotropically etching the layer of silicon nitride over the horizontally-oriented surfaces of the first and second integrated circuit structures and over the horizontally-oriented base surface with an etchant consisting essentially of oxygen and CHF 3 , such that the flow rates of oxygen and CHF 3 have a ratio of about three to one (3:1) and provide a vertical to horizontal etch rate of about 3.7:1 to result in silicon nitride features on the vertically-oriented surfaces of the first and second integrated circuit structures.