Shallow trench isolation (STI) by accounting for the occupation density of raised sections of the insulating film over the dummy patterns

摘要

The method of trench isolation involves forming dummy trenches (202) separated by dummy patterns (203) in element isolation region (201) of the device. The top surface area for the dummy patterns (203) and a width of the dummy trenches (202) is determined by considering the occupation density of the raised sections (209) of the insulating film (208) to be polished to fill trenches (202, 206). By accounting for the additional area of raised portions (209) relative to the area of the dummy patterns (203) caused as a result of the thickness over the sidewalls, dishing and erosion effects caused from polishing away film (208) can be reduced in the memory cell region (205) of the device.