Patent ID: 6103623
Filing Date: 2000-08-15
Classification: H01L

Abstract:
A method for fabricating a metal interconnect structure, and a underlying metal plug structure, on a semiconductor substrate, comprising the steps of:providing a conductive region in said semiconductor substrate;forming a contact hole, with a diameter at the top of said contact hole between about 500 to 5000 Angstroms, in an insulator layer, exposing the top surface of said conductive region in said semiconductor substrate;depositing a composite layer on the top surface of said insulator layer, and on the sides of said contact hole, with said composite layer comprised of an underlying adhesive layer, and an overlying barrier layer;depositing a metal plug layer on composite layer, completely filling said contact hole;depositing an aluminum based metal layer on said metal plug layer;depositing an anti-reflective coating, (ARC), on said aluminum based metal layer;forming a photoresist shape on said ARC layer, in a region directly overlying said contact hole, and with the width of said photoresist shape, larger than the diameter of underlying, said contact hole;performing a first dry etch procedure, in a first dry etching ambient, in which the removal rate of said aluminum based metal layer is greater than the removal rate of said metal plug layer, using said photoresist shape as a mask, forming an aluminum based interconnect structure, with an overlying ARC shape, overlying said metal plug layer, with the width of said aluminum based interconnect structure, larger than said diameter at the top of said contact hole;removing said photoresist shape; andperforming a second dry etch procedure, in a second dry etching ambient, in which the removal rate of said metal plug layer is greater than the removal rate of said aluminum based interconnect structure, using said aluminum based interconnect structure as a mask, forming a metal plug structure, and an underlying composite layer shape, comprised of said barrier layer, and of said adhesive layer, and with a first portion of said metal plug structure comprised of a metal plug, on a first portion of said composite layer shape, in said contact hole, and comprised of a second portion of said metal plug structure, on a second portion of said composite layer shape, located on the top surface of said insulator layer.