Patent ID: 6184107
Filing Date: 2001-02-06
Classification: H01L

Abstract:
A process for forming an active area and shallow trench isolation self-aligned to a deep trench, the process comprising:forming at least one pair of adjacent deep trenches in a substrate and through a first dielectric layer on a surface of the substrate;providing a dielectric collar on at least a portion of a sidewall of each deep trench;filling the deep trenches;recessing a top surface of the trench fill;etching a portion of the trench collars;depositing a strap material on the trench fill and within the recessed trench collars;depositing a second dielectric layer on exposed surfaces of the strap material, the substrate, and the first dielectric layer;planarizing the structure thereby removing portions of the second dielectric layer, such that the second dielectric layer only remains in the deep trenches;depositing a layer of photoresist;patterning the photoresist to expose portions of the second dielectric layer in the deep trenches and portions the first dielectric layer such that at least a portion of the photoresist remains overlapping the deep trench;selectively removing portions of the first dielectric layer between the trenches;selectively removing a portion of the substrate between the trenches;depositing and planarizing a third dielectric layer in spaces created by removal of portions of the first dielectric layer and portions of the second dielectric layer; andremoving remaining portions of the first dielectric layer.