Patent ID: 6670279
Filing Date: 2003-12-30
Classification: H01L

Abstract:
A method of fabricating an STI structure, comprising the steps of:providing a silicon structure having a pad oxide layer formed thereover; forming a hard mask layer over the pad oxide layer; patterning the hard mask layer and the pad oxide layer to form an opening exposing a portion of the silicon structure; the opening having exposed side walls; forming a spacer layer over the patterned hard mask layer, the exposed side walls of the opening and lining the opening; subjecting the structure to an STI trench etching process to: remove the spacer layer from over the patterned hard mask layer; form spacers over the side walls; the spacers being formed in-situ from the spacer layer; and etch an STI trench within the silicon structure wherein the spacers serve as masks during at least a portion of time in which the STI trench is formed; the STI trench having corners; removing any remaining portion of the spacers; forming a liner oxide at least within the STI trench whereby the liner oxide has rounded corners proximate the STI trench corners; forming an STI fill layer over the patterned hard mask layer and filling the liner oxide lined STI trench; planarizing the STI fill layer, stopping on the patterned hard mask layer; and removing the patterned hard mask layer and the patterned pad oxide layer to form a divot-free STI structure having rounded corners.