Patent ID: 6083822
Filing Date: 2000-07-04
Classification: H01L

Abstract:
A method of fabricating a dual damascene metal structure, in a dual damascene opening, on a semiconductor substrate, wherein the dual damascene opening is formed in a composite insulator layer, comprising the steps of:providing an underlying metal interconnect structure;depositing a barrier layer;depositing said composite insulator layer, on said barrier layer, with said composite insulator layer comprised of: an underlying, first insulator layer; a first silicon nitride layer; a second insulator layer; a second silicon nitride layer; and a third insulator layer;using a first photoresist shape as a mask to form a first, initial diameter opening, in said third insulator layer, in said second silicon nitride layer, in said second insulator layer, and in said first silicon nitride layer;using a second photoresist shape as a mask to form a final diameter opening in said third insulator layer, wherein said final diameter is wider than said first, initial diameter, while using said first, initial diameter opening, in said second silicon nitride layer, as a mask for removal of said first insulator layer, creating a second, initial diameter opening, of said dual damascene opening, comprised in said second silicon nitride layer, in said second insulator layer, in said first silicon nitride layer, in said first insulator layer, wherein diameter of said first, initial diameter opening, is equal to diameter of said second, initial diameter opening;removing a region of said barrier layer, exposed at the bottom of said second, initial diameter opening, exposing a portion of the top surface of said underlying, metal interconnect structure, while also removing regions of said second silicon nitride layer, exposed in said final diameter opening; andforming said dual damascene metal structure, in said dual damascene opening, in said composite insulator layer, with said dual damascene metal structure, contacting the top surface of said underlying metal structure, located at the bottom of said dual damascene opening.