Patent ID: 6444522
Filing Date: 2002-09-03
Classification: H01L

Abstract:
A method of manufacturing a flash memory device, comprising the steps of:forming a semiconductor substrate in which field oxide films are formed; forming a first photoresist pattern through which a portion of said semiconductor substrate in which a first well region will be formed is exposed, on said semiconductor substrate, and then implanting an impurity ion having an opposite type to said semiconductor substrate to form a first well region; after removing said first photoresist pattern, forming a second photoresist pattern through which a portion of said semiconductor substrate in which a second well region will be formed is exposed on said semiconductor substrate, and then implanting ions with an ion implantation process to form an anti-diffusion region; implanting an impurity ion of the same type as said semiconductor substrate, into said semiconductor substrate in which said second photoresist pattern is formed, thus forming a second well region; and performing a thermal process for activating impurities in said first well region, said anti-diffusion region and said second well region, thereby forming a triple-well structure having an anti-diffusion region separating said first and second well regions.