Patent ID: 8530327
Filing Date: 2013-09-10
Classification: H01L

Abstract:
1. A method for forming a substantially silicon nitride shallow trench isolation (STI) structure, said method comprising: providing a semiconductor substrate with an upper silicon surface with pad oxide thereon and a trench extending downwardly from said upper silicon surface and including a liner oxide lining said trench; depositing silicon nitride filling said trench and over said upper silicon surface, said silicon nitride having a nitride thickness over said upper silicon surface; performing at least one of a wet nitride etch and a dry nitride etch to substantially uniformly recede said silicon nitride and remove said silicon nitride from over said pad oxide to expose said pad oxide; performing a wet oxide dip to remove said pad oxide, said wet oxide etch dip creating divots along sidewalls of said trench by etching upper parts of said liner oxide; redepositing silicon nitride, said redepositing including filling said divots; and dry etching said silicon nitride in a blanket etching operation to expose said upper silicon surface.