Method for filling recessed micro-structures with metallization in the production of a microelectronic device

• US 20020102837A1
• Filed: 03/28/2002
• Published: 08/01/2002
• Est. Priority Date: 02/04/1998
• Status: Active Grant

• Current Assignee: Lyndon W. Graham, Thomas L. Ritzdorf
• Original Assignee: Lyndon W. Graham, Thomas L. Ritzdorf
• Inventors: Ritzdorf, Thomas L., Graham, Lyndon W.
• Granted Patent: US 6,753,251 B2
• Time in Patent Office: Days
• US Class Current: 438/618
• CPC Class Codes: C25D 5/02 Electroplating of selected surface areas
• CPC Class Codes: C25D 5/10 Electroplating with more than one layer of the same or of different metals for bearings C25D7/10
• CPC Class Codes: C25D 5/18 Electroplating using modulated, pulsed or reversing current
• CPC Class Codes: C25D 5/50 by heat-treatment
• CPC Class Codes: C25D 5/605 Surface topography of the layers, e.g. rough, dendritic or nodular layers
• CPC Class Codes: C25D 5/611 Smooth layers
• CPC Class Codes: C25D 7/123 Semiconductors first coated with a seed layer or a conductive layer
• CPC Class Codes: H01L 21/2885 using an external electrical current, i.e. electro-deposition
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material
• CPC Class Codes: H01L 21/76883 Post-treatment or after-treatment of the conductive material

Abstract

A method for filling recessed micro-structures at a surface of a semiconductor wafer with metallization is set forth. In accordance with the method, a metal layer is deposited into the micro-structures with a process, such as an electroplating process, that generates metal grains that are sufficiently small so as to substantially fill the recessed micro-structures. The deposited metal is subsequently subjected to an annealing process at a temperature below about 100 degrees Celsius, and may even take place at ambient room temperature to allow grain growth which provides optimal electrical properties.

Claims

1. A method for filling recessed micro-structures at a surface of a semiconductor workpiece with copper metallization comprising the steps of:

depositing a copper layer into the micro-structures with a process generating copper grains that are sufficiently small so as to substantially fill the recessed microstructures;

subjecting the deposited copper to an annealing process at a temperature below about 100 degrees Celsius.

2. A method as claimed in claim 1 wherein the copper is deposited using an electroplating process.

3. A method as claimed in claim 1 wherein an electroplating waveform is used, at least in part, to ensure sufficiently small copper grain size.

4. A method as claimed in claim 1 wherein an electroplating solution additive is used, at least in part, to ensure sufficiently small copper grain size.

5. A method as claimed in claim 1 wherein the annealing process is carried out at ambient room temperature.

6. A method for filling recessed micro-structures at a surface of a semiconductor workpiece with metallization comprising the steps of:

depositing a metal layer into the micro-structures with a process generating copper grains that are sufficiently small so as to substantially fill the recessed microstructures;

subjecting the deposited metal to an annealing process at a temperature below about 100 degrees Celsius.

7. A method as claimed in claim 6 wherein the metal is deposited using an electroplating process.

8. A method as claimed in claim 6 wherein an electroplating waveform is used, at least in part, to ensure sufficiently small metal grain size.

9. A method as claimed in claim 6 wherein an electroplating solution additive is used, at least in part, to ensure sufficiently small metal grain size.

10. A method as claimed in claim 6 wherein the annealing process is carried out at ambient room temperature.

11. A method for filling recessed micro-structures at a surface of a semiconductor workpiece with copper metallization comprising the steps of:

providing a semiconductor workpiece with a feature that is to be connected with copper metallization;

applying at least one dielectric layer over a surface of the semiconductor workpiece including the feature;

providing recessed micro-structures in the at least one dielectric layer;

preparing a surface of the workpiece including the recessed micro-structures with a seed layer for subsequent electrochemical copper deposition;

electrochemically depositing a copper layer to the surface of the wafer to substantially fill the recessed micro-structures;

allowing the electrochemically deposited copper layer to self-anneal for a predetermined period of time at ambient room temperature;

removing copper metallization from the surface of the workpiece except from the recessed micro-structures, said removing step occurring after the predetermined period of time has elapsed.

12. A method as claimed in claim 11 wherein the predetermined period is greater than about 20 hours.

13. A method as claimed in claim 11 wherein the step of preparing a surface of the workpiece comprises:

applying at least one barrier layer over the dielectric layer; and

applying a seed layer over the barrier layer.

14. A method as claimed in claim 13 wherein the step of applying the seed layer is defined by applying the seed layer using a chemical vapor deposition process.

15. A method as claimed in claim 13 wherein the step of applying the seed layer is defined by applying the seed layer using a physical vapor deposition process.

16. A method as claimed in claim 11 wherein the step of preparing a surface of the workpiece comprises:

applying at least one adhesion layer over the dielectric layer; and

applying a seed layer over the adhesion layer.

17. A method as claimed in claim 11 wherein the step of removing the copper metallization is defined by removing the copper metallization using a chemical mechanical polish technique.

19. A method as claimed in claim 18 wherein the step of preparing a surface of the workpiece comprises:

applying at least one adhesion layer over the dielectric layer; and

applying a seed layer over the adhesion layer.

20. A method as claimed in claim 18 wherein the step of preparing a surface of the workpiece comprises:

applying at least one barrier layer over the dielectric layer; and

applying a seed layer over the barrier layer.

21. A method as claimed in claim 20 wherein the step of applying the seed layer is defined by applying the seed layer using a chemical vapor deposition process.

22. A method as claimed in claim 20 wherein the step of applying the seed layer is defined by applying the seed layer using a physical vapor deposition process.

23. A method as claimed in claim 18 wherein the step of removing the copper metallization is defined by removing the copper metallization using a chemical mechanical polish technique.

25. A method as claimed in claim 24 wherein the step of preparing a surface of the workpiece comprises:

applying at least one adhesion layer over the dielectric layer; and

applying a seed layer over the adhesion layer.

26. A method as claimed in claim 24 wherein the step of preparing a surface of the workpiece comprises:

applying at least one barrier layer over the dielectric layer; and

applying a seed layer over the barrier layer.

27. A method as claimed in claim 26 wherein the step of applying the seed layer is defined by applying the seed layer using a chemical vapor deposition process.

28. A method as claimed in claim 26 wherein the step of applying the seed layer is defined by applying the seed layer using a physical vapor deposition process.

29. A method as claimed in claim 24 wherein the step of removing the copper metallization is defined by removing the copper metallization using a chemical mechanical polish technique.

18. A method for filling recessed micro-structures at a surface of a semiconductor workpiece with copper metallization comprising the steps of:

providing a semiconductor workpiece with a feature that is to be connected with copper metallization;

applying at least one dielectric layer over a surface of the semiconductor workpiece including the feature;

providing recessed micro-structures in the at least one dielectric layer;

preparing a surface of the workpiece including the recessed micro-structures with a seed layer for subsequent electrochemical copper deposition;

electrochemically depositing a copper layer to the surface of the wafer to substantially fill the recessed micro-structures;

removing copper metallization from the surface of the workpiece except from the recessed micro-structures;

allowing the electrochemically deposited copper layer to self-anneal at ambient room temperature without subjecting the workpiece to a separate and distinct elevated temperature annealing process.

24. A method for filling recessed micro-structures at a surface of a semiconductor workpiece with copper metallization comprising the steps of:

providing a semiconductor workpiece with a feature that is to be connected with copper metallization;

applying at least one dielectric layer over a surface of the semiconductor workpiece including the feature;

providing recessed micro-structures in the at least one dielectric layer;

preparing a surface of the workpiece, including the recessed micro-structures, with a seed layer for subsequent electrochemical copper deposition;

electrochemically depositing a copper layer to the surface of the wafer to substantially fill the recessed micro-structures;

subjecting the electrochemically deposited copper layer to an annealing process at a temperature below about 100 degrees Celsius.

30. A method for filling recessed micro-structures at a surface of a semiconductor workpiece with copper metallization comprising the steps of:

providing a semiconductor workpiece with a feature that is to be connected with copper metallization;

applying at least one low-K dielectric layer over a surface of the semiconductor workpiece including the feature;

providing recessed micro-structures in the at least one low-K dielectric layer;

preparing a surface of the workpiece, including the recessed micro-structures, with a seed layer for subsequent electrochemical copper deposition;

electrochemically depositing a copper layer to the surface of the wafer to substantially fill the recessed micro-structures;

subjecting the electrochemically deposited copper layer to an annealing process at a temperature below which the low-K dielectric layer substantially degrades.

31. A method as claimed in claim 30 wherein the annealing step takes place at a temperature corresponding to a baking temperature of the low-K dielectric.