Patent ID: 6331459
Filing Date: 2001-12-18
Classification: H01L

Abstract:
A method for forming a first region of a semiconductor substrate disposed beneath a surface of such substrate aligned with a second region, such second region having a portion thereof disposed in the semiconductor substrate beneath the surface of the semiconductor substrate, comprising:forming the second region in the semiconductor substrate, such second region having a sidewall portion provided by the semiconductor substrate;forming sacrificial material on the sidewall portion of the second region, such sacrificial material extending from the surface of the semiconductor substrate into the substrate beneath the surface of the semiconductor substrate;forming covering material over the surface of the semiconductor substrate with a portion of the sacrificial material projecting through the covering material to expose such portion of the sacrificial material; andsubjecting the covering material and the exposed portion of the sacrificial material to an etch to selectively remove the sacrificial material from the sidewall portion while leaving the covering material, such removed sacrificial material exposing the sidewall portion of the second region;forming the first region in the semiconductor substrate using the exposed portion of the second region as marker indicating position of the sidewall of the second region.