Patent ID: 7041567
Filing Date: 2006-05-09
Classification: H01L

Abstract:
1. A method of self-aligned fabricating an isolation structure of a trench capacitor, wherein the trench capacitor is disposed in a deep trench of a substrate having a pad layer thereon, the trench capacitor comprising: a conductive layer filled in the deep trench, wherein a top surface of the conductive layer and a sidewall of the pad layer define a recess; and a collar oxide layer disposed on a surface of a sidewall of the deep trench; the method comprising: forming a mask layer and a dielectric layer in sequence on the substrate and a surface of the recess; forming a photoresist layer on the dielectric layer, the photoresist layer having an opening that defines a shallow trench; etching the dielectric layer, the mask layer, and the pad layer through the opening until the substrate is exposed by taking the substrate as an etching stop layer, wherein the conductive layer and the collar oxide layer are not etched at all and remain intact; and etching the substrate by taking the residual mask layer as a hard mask until a surface of the exposed substrate is lower than a top of the collar oxide layer, wherein the conductive layer and the collar oxide layer remain intact.