Patent ID: 6090715
Filing Date: 2000-07-18
Classification: H01L

Abstract:
A masking process for forming first and second ion-doped regions in a substrate of a semiconductor device, said masking process comprising:forming, in order, an oxide layer and a first nitride layer on the substrate;etching the first nitride layer to form a first pattern using a photolithography process, thereby exposing portions of the oxide layer;etching the exposed portions of the oxide layer using the first pattern of the first nitride layer as an etching mask, thereby exposing first portions of the substrate corresponding to the first ion-doped regions;doping first ions into the exposed first portions of the substrate using the first pattern of the first nitride layer as a doping mask;forming a second nitride layer over the substrate and the patterned oxide layer after removing the first pattern of the first nitride layer;removing portions of the second nitride layer to form a second pattern of the second nitride layer;etching the patterned oxide layer using the second pattern of the second nitride layer as an etching mask to expose second portions of the substrate, which correspond to the second ion-doped regions; anddoping second ions into the exposed second portions using the second pattern of the second nitride layer as a doping mask.