Copper alloys for interconnections having improved electromigration characteristics and methods of making same

• US 20040219788A1
• Filed: 06/01/2004
• Published: 11/04/2004
• Est. Priority Date: 12/18/2000
• Status: Active Grant

• Current Assignee: Carolyn Block, Paul Mcgregor, Shu Jin, Thomas N. Marieb
• Original Assignee: Carolyn Block, Paul Mcgregor, Shu Jin, Thomas N. Marieb
• Inventors: McGregor, Paul, Block, Carolyn, Marieb, Thomas N., Jin, Shu
• Granted Patent: US 7,220,674 B2
• Time in Patent Office: Days
• US Class Current: 438/689
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76849 the layer being positioned on top of the main fill metal
• CPC Class Codes: H01L 21/76864 Thermal treatment
• CPC Class Codes: H01L 21/76867 characterized by methods of formation other than PVD, CVD or deposition from a liquids PVD H01L21/2855; CVD H01L21/28556; deposition from liquids H01L21/288
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material
• CPC Class Codes: H01L 23/53238 Additional layers associated with copper layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

Formation of copper alloy interconnect lines on integrated circuits includes introducing dopant elements into a copper layer. Copper alloy interconnect lines may be formed by providing a doping layer over a copper layer, driving dopant material into the copper layer with a high temperature step, and polishing the copper layer to form individual lines. Copper alloy interconnect lines may be formed by implanting dopants into individual lines. Copper alloy interconnect lines may be formed by providing a doped seed layer with a capping layer to prevent premature oxidation, forming an overlying copper layer, driving in the dopants, and polishing to form individual lines. In this way, electromigration resistance and adhesion characteristics may be improved by having relatively higher doping concentrations at outer portions of an interconnect line while the desired low electrical resistivity of the interconnect is maintained by keeping the interior portions of the interconnect with a substantially lower doping concentration.

Claims

1-9. -9. Cancelled.

10. A method of forming a Cu alloy, comprising:

plating a layer of Cu over a substrate; and

implanting at least one dopant element into the Cu layer.

11. The method of claim 10, wherein the at least one dopant element is selected from the group consisting Al, Mg, and Sn.

12. The method of claim 10, further comprising polishing the layer of Cu so as to form individual interconnect lines prior to implanting.

13. The method of claim 12, further comprising depositing a barrier layer over the interconnect lines subsequent to implanting.

14. The method of claim 13, wherein the barrier layer is formed of a material selected from the group consisting of SiC and SiN.

15. The method of claim 12, further comprising depositing a barrier layer over the interconnect lines prior to implanting.

16. The method of claim 12, wherein the dopant is implanted into the surface of the Cu to depth of about 10 monolayers.

17. The method of claim 12, wherein the dopant is implanted a dose of 3E15 atoms/cm² at an energy of 5 keV.

18. The method of claim 12, wherein the dopant is implanted to achieve an implant profile peak at 50 angstroms below the Cu surface and a concentration of 1.5 wt % over 100 angstroms.

19-29. -29. Cancelled.