Patent ID: 7807580
Filing Date: 2010-10-05
Classification: H01L

Abstract:
1. A method of replacing a core top oxide of a memory device comprising a core region and a periphery region on a semiconductor substrate, the core region comprising a core gate oxide, a storage element, a core first top oxide, and a core first poly, the periphery region comprising a periphery gate oxide and a periphery first poly, the method comprising: forming a first mask on the periphery first poly; removing the core first poly and the core first top oxide in the core region; forming a core second top oxide around the storage element in the core region; forming a second poly on the core second top oxide in the core region; and forming a third poly on the second poly in the core region and on the periphery first poly in the periphery region, wherein the upper surface of the third poly in the core region is substantially coplanar with the upper surface of the third poly in the periphery region, wherein the periphery first poly is not substantially damaged or removed by removing the core first poly and the core first top oxide and by forming the core second top oxide, the memory device further comprises a dielectric on the semiconductor substrate in the core region, and the upper surface of the third poly on the dielectric in the core region is substantially coplanar with the upper surface of the third poly in the periphery region, and a sum of heights of the dielectric, the second poly, and the third poly in the core region is substantially equal to a sum of heights of the first poly and the third poly in the periphery region.