Method of forming semiconductor devices containing metal cap layers

• US 7,776,743 B2
• Filed: 07/30/2008
• Issued: 08/17/2010
• Est. Priority Date: 07/30/2008
• Status: Active Grant

• Current Assignee: TEL Manufacturing and Engineering of America, Inc.
• Original Assignee: TEL Epion Inc. (Tokyo Electron Limited)
• Inventors: Cerio, Frank M. Jr., Herdt, Gregory, Russell, Noel
• Primary Examiner(s): Landau; Matthew C
• Assistant Examiner(s): Hall; Jessica
• Application Number:
  US12/182,363
• Publication Number:
  US 20100029071A1
• Time in Patent Office: 748 Days
• Field of Search: 257/E23.011, 257/E23.145, 257/E21.585, 257/E21.586, 257/E21.591, 257/E21.304, 257/760, 257/762, 438/471, 438/473, 438/510, 438/514, 438/515, 438/527, 438/533, 438/546, 438/658, 438/659, 438/686, 438/687, 438/643, 438/669, 438/622, 438/637, 438/675, 438/618, 438/633, 438/778
• US Class Current: 438/687
• CPC Class Codes: H01J 2237/0812 Ionized cluster beam [ICB] sources
• CPC Class Codes: H01L 21/02068 during, before or after processing of conductive layers, e.g. polysilicon or amorphous silicon layers
• CPC Class Codes: H01L 21/3115 Doping the insulating layers
• CPC Class Codes: H01L 21/76825 by exposing the layer to particle radiation, e.g. ion implantation, irradiation with UV light or electrons etc. plasma treatment H01L21/76826
• CPC Class Codes: H01L 21/76834 formation of thin insulating films on the sidewalls or on top of conductors H01L21/76831 takes precedence
• CPC Class Codes: H01L 21/76849 the layer being positioned on top of the main fill metal
• CPC Class Codes: H01L 21/76859 by ion implantation
• CPC Class Codes: H01L 21/76886 Modifying permanently or temporarily the pattern or the conductivity of conductive members, e.g. formation of alloys, reduction of contact resistances

Abstract

Embodiments of methods for improving electrical leakage performance and minimizing electromigration in semiconductor devices containing metal cap layers are generally described herein. According to one embodiment, a method of forming a semiconductor device includes planarizing a top surface of a workpiece to form a substantially planar surface with conductive paths and dielectric regions, forming metal cap layers on the conductive paths, and exposing the top surface of the workpiece to a dopant source from a gas cluster ion beam (GCIB) to form doped metal cap layers on the conductive paths and doped dielectric layers on the dielectric regions. According to some embodiments the metal cap layers and the doped metal cap layers contain a noble metal selected from Pt, Au, Ru, Rh, Ir, and Pd.

Claims

1. A method of forming a semiconductor device, comprising:

planarizing a top surface of a workpiece to form a substantially planar surface with conductive paths and dielectric regions;

forming metal cap layers on the conductive paths; and

exposing the top surface of the workpiece to a dopant source from a gas cluster ion beam (GCIB) to introduce dopants into at least top portions of the metal cap layers and the dielectric regions to form doped metal cap layers on the conductive paths and doped dielectric layers on the dielectric regions.

2. The method of claim 1, wherein forming the metal cap layers comprises selectively forming metal cap layers on the conductive paths relative to the dielectric regions.

3. The method of claim 1, wherein the metal cap layers and the doped metal cap layers contain a noble metal selected from Pt, Au, Ru, Rh, Ir, and Pd.

4. The method of claim 1, wherein the dopant source comprises dopants containing P, B, or N, or a combination thereof.

5. The method of claim 4, wherein the dopant source comprises a stream of ionized gas clusters of dopant-containing molecules selected from PH₃, BH₃, B₂H₆, BF₃, NF₃, and NH₃.

6. The method of claim 4, wherein the doped metal cap layers and doped dielectric layers comprise between 0.1 atomic % and 10 atomic % of the dopants.

7. The method of claim 1, wherein the dopant source further comprises a non-condensable source gas selected from He, Ne, or H₂, or a combination thereof.

8. The method of claim 1, wherein the exposing further forms doped conductive layers between the doped metal cap layers and the conductive paths.

9. The method of claim 1, further comprising:

forming a barrier layer over the doped metal cap layers and the doped dielectric layers.

10. The method of claim 9, wherein the barrier layer comprises silicon nitride, silicon carbide, nitrogen doped silicon carbide, oxygen doped silicon carbide, boron carbon nitride, or boron nitride.

11. The method of claim 9, wherein forming the barrier layer comprises exposing the doped metal cap layers and doped dielectric layers to a gas cluster ion beam (GCIB).

12. The method of claim 1, wherein forming the metal cap layers further comprises forming additional metal on the dielectric regions.

13. The method of claim 12, wherein the exposing to a dopant source from GCIB removes at least a portion of the additional metal from the dielectric regions.

14. The method of claim 13, wherein the exposing comprises simultaneous or sequential GCIB exposures of different dopant sources.

15. A method of forming a semiconductor device, comprising:

planarizing a top surface of a workpiece to form a substantially planar surface with conductive paths and dielectric regions;

selectively forming metal cap layers on the conductive paths relative to the dielectric regions, wherein the metal cap layers contain a noble metal selected from Pt, Au, Ru, Rh, Ir, and Pd; and

exposing the top surface of the workpiece to a dopant source containing dopants selected from P, B, or N, or a combination thereof, from a gas cluster ion beam (GCIB) to introduce the dopants into at least top portions of the metal cap layers and the dielectric regions to form doped metal cap layers on the conductive paths and doped dielectric layers on the dielectric regions, each comprising between 0.1 atomic % and 10 atomic % of the dopant.

16. The method of claim 15, wherein the dopant source comprises a stream of ionized gas clusters of dopant-containing molecules selected from PH₃, BH₃, B₂H₆, BF₃, NF₃, and NH₃, and a non-condensable source gas selected from He, Ne, or H₂, or a combination thereof.

17. The method of claim 15, wherein the exposing further forms doped conductive layers between the doped metal cap layers and the conductive paths.

18. The method of claim 15, further comprising:

forming a barrier layer comprising silicon nitride, silicon carbide, nitrogen doped silicon carbide, oxygen doped silicon carbide, boron carbon nitride, or boron nitride over the doped metal cap layers and the doped dielectric layers by exposing the doped metal cap layers and doped dielectric layers to a GCIB.

19. A method of forming a semiconductor device, comprising:

planarizing a top surface of a workpiece to form a substantially planar surface with conductive paths and dielectric regions;

forming metal cap layers on the conductive paths and additional metal on the dielectric regions, wherein the metal cap layers and the additional metal contain a noble metal selected from Pt, Au, Ru, Rh, Ir, and Pd; and

exposing the top surface of the workpiece to a dopant source containing dopants selected from P, B, or N, or a combination thereof, from a gas cluster ion beam (GCIB) to remove at least a portion of the additional metal from the dielectric regions and to introduce the dopants into at least top portions of the metal cap layers and the dielectric regions to form doped metal cap layers on the conductive paths and doped dielectric layers on the dielectric regions, each comprising between 0.1 atomic % and 10 atomic % of the dopant.

20. The method of claim 19, wherein the dopant source comprises a stream of ionized gas clusters of dopant-containing molecules selected from PH₃, BH₃, B₂H₆, BF₃, NF₃, and NH₃, and a non-condensable source gas selected from He, Ne, or H₂, or a combination thereof.

21. The method of claim 19, wherein the exposing further forms doped conductive layers between the doped metal cap layers and the conductive paths.

22. The method of claim 19, further comprising:

forming a barrier layer comprising silicon nitride, silicon carbide, nitrogen doped silicon carbide, oxygen doped silicon carbide, boron carbon nitride, or boron nitride over the doped metal cap layers and the doped dielectric layers by exposing the doped metal cap layers and doped dielectric layers to a GCIB.

23. The method of claim 19, wherein the exposing comprises simultaneous or sequential GCIB exposures of different dopant sources.