Patent ID: 6936522
Filing Date: 2005-08-30
Classification: H01L

Abstract:
1. A method of forming an isolation structure comprising, in the order recited: (a) providing a semiconductor substrate; (b) forming a buried N-doped region in said substrate; (c) forming a vertical trench in said substrate, said trench extending into said N-doped region; (d) removing said N-doped region to form a lateral trench communicating with and extending perpendicular to said vertical trench; (e) partially filling said vertical and lateral trenches with a first insulating material; (f) removing said first insulating material from said vertical trench; (g) filling unfilled portions of said lateral trench and refilling said vertical trench with said first insulating material; (h) removing said first insulating material from said vertical trench; and (i) refilling said vertical trench with a second insulating material.