Patent ID: 6218307
Filing Date: 2001-04-17
Classification: H01L

Abstract:
A method of fabricating a shallow trench isolation structure, comprising the steps of:forming a pad oxide layer and a pad silicon nitride layer over a substrate;etching the pad oxide layer, the pad silicon nitride layer, and the substrate to form a trench in the substrate;forming a high-density plasma (HDP) oxide layer by HDP deposition to fill the trench, wherein the HDP oxide layer contains a first portion and a second portion, the first portion is deposited in the trench and the second portion is deposited over the pad silicon nitride layer, and the HDP deposition is controlled such that a thickness of the HDP oxide layer is not smaller than the depth of the trench plus the thickness of the pad oxide layer, and not larger than the depth of the trench plus the thickness of the pad oxide layer and the thickness of the pad silicon nitride layer;forming a silicon nitride layer over the substrate covering both the first portion and the second portion of the HDP oxide layer, wherein the silicon nitride layer and the second portion of the HDP oxide layer together form a protruding portion;performing a chemical-mechanical polishing to remove at least a part of the protruding portion including the silicon nitride layer formed thereon;etching the HDP oxide layer until the second portion of the HDP oxide layer is removed; andremoving the pad silicon nitride layer and the silicon nitride layer covering the first portion of the HDP oxide layer by etching.