Patent ID: 6555442
Filing Date: 2003-04-29
Classification: H01L

Abstract:
A method-of fabricating an STI, comprising the steps of:providing a silicon structure having a pad oxide layer formed thereover; forming an undoped poly buffer layer over the pad oxide layer; forming a hard mask layer over the undoped poly buffer layer; patterning the hard mask layer, the undoped poly buffer layer and the pad oxide layer to form an opening exposing a portion of the silicon structure within an active area; the opening having exposed side walls; forming inorganic spacers over the exposed side walls; using the patterned hard mask layer and the spacers as hard masks, etching the silicon structure to form an STI opening within the active area; removing the inorganic spacers exposing the upper corners of the STI opening; using an oxidation process, forming a liner oxide layer within the STI opening, over the upper corners of the STI opening and at least the patterned undoped poly buffer layer exposed by the removal of the inorganic spacers; forming an STI oxide layer over the patterned hard mask layer filling the liner oxide layer lined STI opening; and planarizing the STI oxide layer and removing: the patterned hard mask; the patterned undoped poly buffer layer; and the patterned pad oxide layer to fabricate the STI having rounded corners and without substantial divots.