METHOD OF FORMING SHALLOW TRENCH ISOLATION STRUCTURES FOR INTEGRATED CIRCUITS

摘要

METHOD OF FORMING SHALLOW TRENCHISOLATION STRUCTURES FOR INTEGRATED CIRCUITS A BSTRACTA method of forming shallow trench isolation (STI) stcutures using a multi-step etchpion ss is disclosed. The first etch step is performed by selectively etching the substrate at a substantially higher etching rate than the mask layer to form preliminary openings having steep taper angles. The second etch step is performed by non-selectively etching the substrate to deepen the preliminary openings to form STI gaps with substantially flat bottoms.Fig. 2