Patent ID: 6756313
Filing Date: 2004-06-29
Classification: H01L

Abstract:
A method of selectively etching silicon nitride spacers for sub 0.25 &mgr;m devices, where the selectivity of silicon nitride relative to silicon oxide is in the range of about 15:1 to about 24:1, the method comprising:a) providing a substrate which includes a silicon oxide layer adjacent to a silicon nitride layer, wherein said silicon oxide layer is or becomes exposed during said etching of said silicon nitride; b) etching said silicon nitride layer to form at least one silicon nitride spacer, wherein the upper shoulder of the spacer is rounded, and said etching is carried out using a plasma source gas including SF6, HBr, and N2, wherein a pressure in an etch chamber in which said etching is carried out is at least 35 mTorr, and wherein a temperature of said substrate during said etching is less than about 75Â° C.