Patent ID: 6225199
Filing Date: 2001-05-01
Classification: H01L

Abstract:
A method of forming a semiconductor device comprising:forming a first mask pattern for defining a first well region on a semiconductor substrate of a first conductivity type;using said first mask pattern and large tilted-implanting impurity ions of a second conductivity type into said semiconductor substrate having a predetermined orient angle in the middle of circulation thereof to form a first well isolation region;using said first mask pattern again and implanting impurity ions of a first conductivity type into said substrate to form a first well region as to be overlaid on a portion of said first well isolation region;removing said first mask pattern;forming a second mask pattern for defining a second well region on the semiconductor substrate;using said second mask pattern and implanting impunity ions of a first conductivity type to form a second well region as to be spaced apart from said first well region;removing said second mask pattern;forming a third mask pattern for defining a third well region on said substrate outside of said first and second well regions; andusing said third mask and implanting impurity ions of a second conductivity type to form a third well region surrounding at least both sidewalls of said first well region.