Hybrid ionized physical vapor deposition of via and trench liners

Abstract

A hybrid ionized physical vapor deposition technique to form liner films for vias, trenches, and other structures of integrated circuits. The techniques involves depositing liner materials within a via, hole, trench, or other structure in a neutral state, using, for example, physical vapor deposition. The liner materials deposited in this step have an ionization ratio of less than ten percent, and no bias potential is applied to an underlying substrate. The technique also involves depositing liner materials in ionized form in the same via using ionized physical vapor deposition. The liner materials deposited in this step have an ionization ratio far more than ten percent, and an optional bias potential may be applied to the underlying substrate. After liner film is formed, any other suitable actions or processing steps may take place including building additional metallization and dielectric layers and vias or trenches to produce a multi-level interconnect system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this disclosure, reference is now made to the following description, taken in conjunction with the accompanying drawing, in which:

FIG. 1 illustrates an interconnect structure formed using physical vapor deposition;

FIG. 2 illustrates an interconnect structure formed using ionized physical vapor deposition;

FIG. 3 illustrates an example interconnect structure formed using hybrid ionized physical vapor deposition according to one embodiment of this disclosure;

FIG. 4 illustrates an example method for hybrid ionized physical vapor deposition of via and trench liners according to one embodiment of this disclosure; and

FIGS. 5A through 5C illustrate example test results of interconnect structures formed using different techniques according to one embodiment of this disclosure.

Claims

1. A method of fabricating interconnect structure having a substrate and a via, the via disposed in a dielectric layer and a metallization layer of the interconnect structure, the method comprising: depositing liner material into the via using physical vapor deposition; anddepositing an ionized form of the liner material into the via using physical vapor deposition to form a liner film in the via.

2. The method according to claim 1 further comprising: applying a bias potential to the substrate.

3. The method according to claim 1, wherein the liner material has an ionization ratio less than 10%.

4. The method according to claim 1, wherein the ionized form of the liner material comprises an ionization ratio of more than 10%.

5. The method according to claim 1, wherein the ionized form of the liner material is deposited on a bottom surface of the via.

6. The method according to claim 1, wherein the ionized form of the liner material redistributes the liner material at the top of the via to prevent overhang formation.

7. The method according to claim 1, wherein the ionized form of the liner material is deposited at a normal incidence relative to the substrate.

8. The method according to claim 1, wherein ambient pressure is lower during the step of depositing the liner material in a neutral state than during the step of depositing the ionized form of liner material.

9. The method according to claim 1, wherein the via comprises a high aspect ratio.

10. The method according to claim 1 further comprising: disposing on the liner film at least one of: a second liner film, a second metallization layer, a second dielectric layer, and a second via.

11. An interconnect structure having a substrate, a dielectric layer and a metallization layer, the interconnect structure comprising: a via disposed in the dielectric layer and the metallization layer; anda liner film in the via formed by depositing liner material into the via using physical vapor deposition and depositing an ionized form of the liner material into the via using physical vapor deposition.

12. The interconnect structure according to claim 11, wherein the via comprises a high aspect ratio.

13. The interconnect structure according to claim 11 further comprises at least one of: a second liner film layer, a second metallization layer, a second dielectric layer, and a second via, formed on the via.

14. For use in integrated circuits, a method of fabricating a via liner, the method comprising: depositing liner material into a via using physical vapor deposition, wherein the via is disposed in a dielectric layer and a metallization layer; anddepositing an ionized form of the liner material into the via using physical vapor deposition to form a liner film in the via.

15. The method according to claim 14 further comprising: applying a bias potential to the substrate.

16. The method according to claim 14, wherein the liner material has an ionization ratio less than 10%, and wherein the ionized form of the liner material has an ionization ratio of more than 10%.

17. The method according to claim 14, wherein the ionized form of the liner material is deposited on a bottom surface of the via.

18. The method according to claim 14, wherein the ionized form of the liner material redistributes the liner material at the top of the via to prevent overhang formation.

19. The method according to claim 14, wherein the ionized form of the liner material is deposited at a normal incidence relative to a substrate of the integrated circuit.

20. The method according to claim 14, wherein the via comprises a high aspect ratio.