Method of processing a defect source at a wafer edge region in a semiconductor manufacturing

Abstract

The present invention provides a method of eliminating or covering a defect source in a wafer edge region for semiconductor fabrication. During the etching process of a sacrificial oxide layer for storage node openings, the sacrificial oxide layer has a rumple topology in the wafer edge region due to etching non-uniformity of a photoresist layer formed on the sacrificial oxide layer. Subsequent deposition of a conductive layer and planarization etching, the conductive layer undesirably remains at the wafer edge region as a defect source. Such conductive contaminant particles dislodge, causing many problems in the wafer main region. The present invention removes such a defect source via two methods. One is to directly remove the defect source using a photoresist pattern exposing thereof. The other is to fix the defect source in place in the wafer edge region by protecting thereof by a photoresist pattern during subsequent cleaning processes.