Patent ID: 6399465
Filing Date: 2002-06-04
Classification: H01L

Abstract:
A method of forming a triple well structure, comprising the steps of:providing a substrate; forming a first photoresist layer on the substrate, wherein the first photoresist layer has a first pattern exposing a portion of the substrate; performing a first ion implantation process to form a first well in the substrate; baking the first photoresist layer to expand the first pattern of the first photoresist layer; performing a second ion implantation process to form a first doped region in the substrate under the first well; removing the photoresist layer; forming a second photoresist layer on the substrate, wherein the second photoresist layer has a second pattern; performing a third ion implantation process to form a second doped region around the first well and to form a second well in the substrate, wherein a bottom of the second doped region overlaps with a side portion of the first doped region.