Methods for Fabricating Contacts to Pillar Structures in Integrated Circuits

• US 20090091037A1
• Filed: 10/03/2007
• Published: 04/09/2009
• Est. Priority Date: 10/03/2007
• Status: Active Grant

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines SA (International Business Machines Corporation)
• Inventors: Costrini, Gregory, Rooks, Michael J., Sun, Jonathan Zanhong, Assefa, Solomon, Jahnes, Christopher Vincent
• Granted Patent: US 8,008,095 B2
• Time in Patent Office: Days
• US Class Current: 257/773
• CPC Class Codes: H10N 50/01 Manufacture or treatment

Abstract

A pillar structure that is contacted by a vertical contact is formed in an integrated circuit. A hard mask is formed and utilized to pattern a least a portion of the pillar structure. The hard mask comprises carbon. Subsequently, the hard mask is removed. A conductive material is then deposited in a region previously occupied by the hard mask to form the vertical contact. The hard mask may, for example, comprise diamond-like carbon. The pillar structure may have a width or diameter less than about 100 nanometers.

Claims

1. A method of forming a pillar structure that is contacted by a vertical contact in an integrated circuit, the method comprising the steps of:

forming a hard mask, the hard mask comprising carbon;

utilizing the hard mask to pattern at least a portion of the pillar structure;

removing the hard mask; and

depositing a conductive material into a region previously occupied by the hard mask to form the vertical contact.

2. The method of claim 1, wherein the hard mask comprises diamond-like carbon.

3. The method of claim 1, wherein the hard mask comprises diamond, graphite, or hydrocarbon polymer.

4. The method of claim 1, wherein the pillar structure comprises a magnetic tunnel junction.

5. The method of claim 1, wherein the pillar structure comprises a spin-valve structure.

6. The method of claim 1, wherein the pillar structure comprises a phase-change memory structure.

7. The method of claim 1, wherein the step of utilizing the hard mask to pattern at least a portion of the pillar structure comprises reactive ion etching.

8. The method of claim 1, wherein the step of utilizing the hard mask to pattern at least a portion of the pillar structure comprises ion milling.

9. The method of claim 1, wherein the step of removing the hard mask comprises etching with a plasma comprising atomic oxygen or atomic hydrogen, or a combination thereof.

10. The method of claim 1, wherein the vertical contact connects the pillar structure to a conductive line, the conductive line at least partially overlying the pillar structure.

11. The method of claim 10, wherein the conductive line is formed by patterning a trench into a dielectric layer, the trench at least partially overlying the hard mask.

12. The method of claim 11, wherein the step of depositing a conductive material into the region previously occupied by the hard mask further comprises depositing the conductive material into the trench in the dielectric layer.

13. The method of claim 1, wherein the vertical contact is self-aligned to the pillar structure.

14. The method of claim 1, further comprising the step of forming a dielectric layer on top of the hard mask.

15. The method of claim 14, further comprising the step of removing the dielectric layer from the top of the hard mask by chemical mechanical polishing.

16. The method of claim 14, further comprising the step of removing the dielectric layer from the top of the hard mask by reactive ion etching.

17. The method of claim 1, further comprising the step of narrowing the hard mask without reducing the height of the hard mask.

18. The method of claim 1, wherein the pillar structure has a width or diameter less than about 100 nanometers.

19. A pillar structure that is contacted by a vertical contact in an integrated circuit, the pillar structure and vertical contact formed at least in part by the steps of:

forming a hard mask, the hard mask comprising carbon;

utilizing the hard mask to pattern at least a portion of the pillar structure;

removing the hard mask; and

depositing a conductive material into a region previously occupied by the hard mask to form the vertical contact.

20. An integrated circuit comprising a pillar structure that is contacted by a vertical contact, the pillar structure and the vertical contact formed at least in part by the steps of:

forming a hard mask, the hard mask comprising carbon;

utilizing the hard mask to pattern at least a portion of the pillar structure;

removing the hard mask; and

depositing a conductive material into a region previously occupied by the hard mask to form the vertical contact.