US 6,284,653 B1 · Method of selectively forming a barrier layer from a directionally deposited metal layer

Abstract

A process for forming a composite structure, comprised of an overlying titanium nitride barrier layer, and an underlying titanium disilicide layer, located on a portion of a conductive region in a semiconductor substrate exposed at the bottom of a high aspect ratio contact hole, has been developed. A first iteration of this invention entails the deposition of a titanium ion layer, via an anisotropic, ion metal plasma (IMP), procedure, on the exposed portion of the conductive region, as well as on the top surface of the insulator layer in which the high aspect ratio contact hole was formed in. A first anneal cycle results in the formation of a titanium disilicide layer on the conductive region, leaving an unreacted titanium ion layer on the surface of the insulator layer. After removal of unreacted titanium, a second anneal cycle is performed in a nitrogen containing ambient, converting a top portion of the titanium disilicide layer to a titanium nitride barrier layer. A tungsten plug structure is then formed on titanium nitride-titanium disilicide layer, in the high aspect ratio contact hole. A second iteration of this invention features IMP deposition of the titanium ion layer on the exposed conductive region, at the bottom of the contact hole, as well as on the top surface of the photoresist shape used for definition of the high aspect ratio contact hole. After removal of the photoresist shape, and of the titanium ion layer located on the top surface of the photoresist shape, subsequent anneal cycles are performed resulting in the desired composite, titanium nitride-titanium disilicide structure, on the conductive region.

Claims20

Dependent claims

A method of forming a metal silicide layer, and an overlying barrier layer, on a portion of a conductive region in a semiconductor substrate, exposed at the bottom of a contact hole, comprising the steps of:

providing said conductive region, in said semiconductor substrate;
depositing an insulator layer;
opening a contact hole in said insulator layer, exposing said portion of top surface of said conductive region, located at the bottom of said contact hole;
performing an anisotropic, ion metal plasma (IMP), deposition procedure, depositing a first metal ion layer on said portion of said conductive region, exposed at the bottom of said contact hole, and depositing a second metal ion layer on the top surface of said insulator layer;
performing a first anneal procedure to form said metal silicide layer from said first metal ion layer, on said portion of said conductive region exposed at the bottom of said contact hole, while said second metal ion layer, located on said insulator layer, remains unreacted;
selectively removing said second metal ion layer from the top surface of said insulator layer;
performing a second anneal procedure in a nitrogen containing ambient, to convert a top portion of said metal silicide layer to a barrier layer, resulting in a composite structure on said portion of said conductive region exposed at the bottom of said contact hole, with said composite structure comprised of said barrier layer on a bottom portion of said metal silicide layer;
forming a metal plug structure in said contact hole, overlying and contacting said composite structure;
and
forming a metal interconnect structure, overlying and contacting top surface of said metal plug structure.

7 more elements

A method of selectively forming a composite structure, comprised of a titanium nitride barrier layer on a titanium disilicide layer, located on a portion of a conductive region in a semiconductor substrate exposed at the bottom of a high aspect ratio contact hole, and featuring a photoresist lift-off procedure used to remove unwanted portions of

a metal ion layer, comprising the steps of:
providing said conductive region in said semiconductor substrate;
depositing an insulator layer;
performing an anisotropic dry etch procedure, using a photoresist shape as an etch mask, to form said high aspect ratio contact hole in said insulator layer, exposing a portion of the top surface of said conductive region, located at the bottom of said high aspect ratio contact hole;
performing an anisotropic, ion metal plasma (IMP), procedure, depositing a first titanium ion layer on the portion of said conductive region exposed at the bottom of said high aspect ratio contact hole, and depositing a second titanium ion layer on the top surface of said photoresist shape;
removing said photoresist shape, and lifting off said second titanium ion layer during a photoresist removal procedure;
performing a first anneal procedure to form said titanium disilicide layer from said first titanium ion layer, on the portion of said conductive region exposed at the bottom of said high aspect ratio contact hole;
performing a second anneal procedure in a nitrogen containing ambient, to convert a top portion of said titanium disilicide layer to a first titanium nitride barrier layer, resulting in said composite structure located on the portion of said conductive region exposed at the bottom of said high aspect ratio contact hole, with said composite structure comprised of said first titanium nitride barrier layer on a bottom portion of said titanium disilicide layer;
forming a tungsten plug structure in said high aspect ratio contact hole, overlying and contacting said composite structure;
and
forming a metal interconnect structure, overlying and contacting said tungsten plug structure.

8 more elements

Dependencies are inferred from the claim text.

Method of selectively forming a barrier layer from a directionally deposited metal layer

Life of this patent

Method of selectively forming a barrier layer from a directionally deposited metal layer

Life of this patent

Abstract

Claims20