Methods and apparatus for making integrated-circuit wiring from copper, silver, gold, and other metals

• US 20040206308A1
• Filed: 05/07/2004
• Published: 10/21/2004
• Est. Priority Date: 01/18/2000
• Status: Active Grant

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Ahn, Kie Y., Forbes, Leonard
• Granted Patent: US 7,285,196 B2
• Time in Patent Office: Days
• US Class Current: 118/723MP
• CPC Class Codes: C23C 14/3471 Introduction of auxiliary energy into the plasma
• CPC Class Codes: C23C 16/517 using a combination of discharges covered by two or more of groups C23C16/503 - C23C16/515
• CPC Class Codes: G02F 1/13454 Drivers integrated on the active matrix substrate G02F1/136277 takes precedence
• CPC Class Codes: H01J 37/3408 Planar magnetron sputtering
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76846 Layer combinations
• CPC Class Codes: H01L 21/76856 by treatment in plasmas or gaseous environments, e.g. nitriding a refractory metal liner
• CPC Class Codes: H01L 21/76873 for electroplating
• CPC Class Codes: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621

Abstract

In recent years, copper wiring has emerged as a promising substitute for the aluminum wiring in integrated circuits, because copper offers lower electrical resistance and better reliability at smaller dimensions than aluminum. However, use of copper typically requires forming a diffusion barrier to prevent contamination of other parts of an integrated circuit and forming a seed layer to facilitate copper plating steps. Unfortunately, conventional methods of forming the diffusion barriers and seed layers require use of separate wafer-processing chambers, giving rise to transport delays and the introduction of defect-causing particles. Accordingly, the inventors devised unique wafer-processing chambers and methods of forming barrier and seed layers. One embodiment of the wafer-processing chamber includes equipment for physical vapor deposition and equipment for chemical vapor deposition to facilitate formation of diffusion barriers and seed layers within one chamber, thereby promoting fabrication efficiency and reducing defects.

Claims

1. A processing chamber for one or more integrated-circuit assemblies, comprising means for sputtering a material and means for vapor-depositing a material.

2. The processing chamber of claim 1, wherein the means for sputtering and means for vapor-depositing include a common chamber.

3. The processing chamber of claim 1, wherein the means for vapor-depositing includes a copper deposition device.

4. The processing chamber of claim 1, wherein the means for vapor-depositing includes a silver deposition device.

5. The processing chamber of claim 1, wherein the means for vapor-depositing includes a gold deposition device.

6. The processing chamber of claim 1, wherein the means for vapor-depositing is adapted to form a graded composition of WSi_x, where x varies from 2.0 to 2.5.

7. The processing chamber of claim 6, wherein the means for vapor-depositing is adapted to nitride the graded composition of WSi_x.

8. The processing chamber of claim 7, wherein the means for vapor-depositing is adapted to introduce ECR plasma and excite the introduced plasma with argon gas.

9. The processing chamber of claim 1, wherein the means for sputtering operates before the means for vapor-depositing.

10. A processing chamber for one or more integrated-circuit assemblies, comprising:

means for holding a sputter target;

means for depositing a material including means for vapor-depositing; and

means for preventing contamination of the sputter target during operation of the means for vapor-depositing the material.

11. The processing chamber of claim 10, wherein the means for holding a sputter target include a sputter device positioned below the sputter target.

12. The processing chamber of claim 10, wherein the means for preventing contamination include a gas source adapted to sweep a sputter target during operation of the means for vapor-depositing the material.

13. The processing chamber of claim 10, wherein the means for vapor-depositing is adapted to deposit tungsten.

14. The processing chamber of claim 13, wherein means for vapor-depositing is adapted to deposit tungsten by introducing tungsten hexafluoride and hydrogen gases, introducing silane gas, and terminating introduction of silane gas before terminating introduction of tungsten hexafluoride and hydrogen gases.

15. The processing chamber of claim 14, wherein the means for depositing is adapted to deposit at least one of a group consisting essentially copper, silver, and gold.

16. A processing chamber for one or more integrated-circuit assemblies, comprising:

means for holding a sputter target within the chamber;

plasma means for introducing a plasma into the chamber;

means for vapor-deposition; and

means for isolating the plasma means from the means for vapor-deposition during operation of the means for vapor-depositing.

17. The processing chamber of claim 16, wherein the plasma means includes an ECR source.

18. The processing chamber of claim 16, wherein the means for vapor-deposition includes a plurality of gas sources and a plurality of mass flow-controllers.

19. The processing chamber of claim 18, wherein the plurality of gas sources include a WF₆ source, a SiH₄ source, and an N₂ source.

20. The processing chamber of claim 16, wherein the means for isolating includes an isolation valve positioned in an inlet into the chamber.

21. A processing chamber for one or more integrated-circuit assemblies, comprising:

means for holding a sputter target within the chamber;

plasma means for introducing a plasma into the chamber;

means for vapor-deposition;

means for isolating the plasma means from the means for vapor-deposition during operation of the means for vapor-depositing; and

means for preventing contamination of the sputter target during operation of the means for vapor-depositing the material.

22. The processing chamber of claim 21, wherein the means for preventing contamination includes a gas source adapted to sweep the sputter target.

23. The processing chamber of claim 22, wherein the gas source includes one or more turns of electrically conductive tubing.

24. The processing chamber of claim 23, wherein the gas source includes an RF emission coil.

25. The processing chamber of claim 21, wherein the means for vapor-deposition is adapted to deposit a graded composition of WSi_x, wherein x is in a range of about 2.0 to 2.5.

26. The processing chamber of claim 25, wherein the means for vapor-deposition is adapted to nitride the graded composition of WSi_x.

27. A processing chamber for one or more integrated-circuit assemblies, comprising:

a wafer holder for holding a wafer or substrate;

means for sputtering a material onto a surface of a wafer held by the wafer holder, including;

one or more sputter-target holders within the chamber for holding a sputter target;

a plasma source coupled to the chamber; and

means for vapor-depositing a material, including;

one or more mass-flow controllers coupled to the chamber; and

a gas-emission tube coupled to at least one of the mass-flow controllers and having one or more orifices oriented for emitting gas toward a sputter target held by the one or more sputter target holders.

29. Apparatus for processing one or more integrated-circuit assemblies, comprising:

a chamber;

a sputtering target holder within the chamber;

an electron-cyclotron-resonance plasma source coupled to the chamber; and

a mass-flow controller coupled to the chamber.

28. The processing chamber of claim 30, wherein the gas-emission tube comprises a coiled tube having one or more turns.

30. The apparatus of claim 29, wherein the chamber includes walls of stainless steel or glass.

31. The apparatus of claim 29, wherein the chamber includes an RF-gas emission coil below the sputtering target holder.

32. The apparatus of claim 31, wherein the coil includes a horizontal spiral.

33. The apparatus of claim 31, wherein the coil includes two turns of 6.5 millimeter tubing.

34. The apparatus of claim 29, wherein the sputtering target holder is adapted to hold a copper target.

35. The apparatus of claim 34, wherein the sputtering target holder is adapted to provide a bias voltage to a target.

36. The apparatus of claim 29, wherein the plasma source includes an isolation valve adapted to selectively isolate the plasma source from the chamber.

37. The apparatus of claim 29, wherein the mass-flow controllers are adapted to selectively fluidly couple gas sources to the chamber.