US 7,745,332 B1 · PVD-based metallization methods for fabrication of interconnections in semiconductor devices

Abstract

Recessed features on a Damascene substrate are filled with metal using plasma PVD. Recessed features having widths of less than about 300 nm, e.g., between about 30-300 nm can be filled with metals (e.g., copper and aluminum), without forming voids. In one approach, the deposition is performed by exposing the substrate to a high-density plasma characterized by high fractional ionization of metal. Under these conditions, the metal is deposited within the recess, without forming large overhang at the opening of the recess. In some embodiments, the metal is deposited within the recess, while diffusion barrier material is simultaneously etched from the field region. In a second approach, recessed features are filled by performing a plurality of profiling cycles, wherein each cycle includes a net etching and a net depositing operation. Etching and depositing parameters are adjusted such that the recessed features are filled without forming overhangs and voids.

Claims62

Dependent claims

A method of filling a recessed feature on a semiconductor substrate with a metal-containing material, the method comprising:

(a) depositing a layer of the metal-containing material on the semiconductor substrate, to coat at least a bottom portion of the recessed feature;
and
(b) performing a plurality of profiling cycles, wherein each profiling cycle comprises a net etching operation removing a first portion of a material residing at the bottom of the recessed feature and a net deposition operation depositing a second portion of a material at the bottom of the recessed feature, wherein the net etching operation comprises redistributing the metal-containing material from the bottom portion of the recessed feature to the sidewalls of the recessed feature in at least some profiling cycles, and wherein performing the plurality of profiling cycles fills the recessed feature with the metal-containing material, wherein removing the first portion of a material residing at the bottom of the recessed feature comprises resputtering the material using high density plasma resputtering in at least some profiling cycles.

An apparatus for filling recessed features on a wafer substrate, comprising:

(a) a process chamber configured to hold a metal target;
(b) a wafer support for holding the wafer in position during deposition of a metal-containing material;
and
(c) a controller comprising program instructions for
(i) depositing a layer of the metal-containing material on the semiconductor substrate, to coat at least some portions of the substrate residing above the bottom of the recessed feature;
and
(ii) performing at least one profiling cycle, wherein the profiling cycle comprises a first operation and a second operation, said first operation comprising removing a first portion of the metal-containing material residing above the bottom of the recessed feature and redistributing at least some of said material to the bottom of the recessed feature such that no net etching occurs at the bottom of the feature by resputtering the material residing above the bottom of the recessed feature under a pressure that is sufficient to reflect at least some of said material to the bottom of the recessed feature, said second operation comprising depositing a second portion of a material at least onto some portions of the substrate residing above the bottom of the recessed feature, wherein performing the at least one profiling cycle achieves net material deposition at the bottom of the recessed feature.

4 more elements

An apparatus for filling recessed features on a wafer substrate, comprising:

(a) a first process chamber configured to hold a metal target and configured for depositing a metal-containing material;
(b) a second process chamber without a metal target and configured for material etching;
and
(c) a controller comprising program instructions for
(i) depositing a layer of the metal-containing material on the semiconductor substrate, to coat at least some portions of the substrate residing above the bottom of the recessed feature, in the first process chamber;
and
(ii) performing at least one profiling cycle, wherein the profiling cycle comprises a first operation and a second operation, said first operation comprising removing a first portion of the metal-containing material residing above the bottom of the recessed feature and redistributing at least some of said material to the bottom of the recessed feature such that no net etching occurs at the bottom of the feature by resputtering the material residing above the bottom of the recessed feature under a pressure that is sufficient to reflect at least some of said material to the bottom of the recessed feature in the second process chamber;
said second operation comprising depositing a second portion of the metal-containing material at least onto some portions of the substrate residing above the bottom of the recessed feature in the first process chamber, wherein performing the at least one profiling cycle achieves net material deposition at the bottom of the recessed feature.

5 more elements

Dependencies are inferred from the claim text.

PVD-based metallization methods for fabrication of interconnections in semiconductor devices

Life of this patent

PVD-based metallization methods for fabrication of interconnections in semiconductor devices

Life of this patent

Abstract

Claims62