Cobalt-containing material removal

Patent metadata

Field	Value
Publication number	US-9947549-B1
Application number	US-201615332849-A
Country	US
Kind code	B1
Filing date	Oct 24, 2016
Priority date	Oct 10, 2016
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

Methods are described herein for etching cobalt films which are difficult to volatize. The methods include exposing a cobalt film to a bromine or chlorine-containing precursor with a concurrent local plasma which applies a bias to the impinging etchants. Cobalt halide is formed on the surface at the same time an amorphized cobalt layer is formed near the surface. A carbon-and-nitrogen-containing precursor is later delivered to the substrate processing region to form volatile cobalt complexes which desorb from the surface of the cobalt film. Cobalt may be selectively removed. The concurrent production of cobalt halide and amorphized regions was found to markedly increase the overall etch rate and markedly improve surface smoothness upon exposure to the carbon-and-nitrogen-containing precursor. All the recited steps may now be performed in the same substrate processing chamber.

First claim

The invention claimed is:

1. A method of etching cobalt and cobalt oxide, the method comprising:
transferring a substrate into a substrate processing region, wherein the substrate comprises cobalt and a thin cobalt oxide layer thereon;
removing the thin cobalt oxide layer by flowing a hydrogen-containing precursor into the substrate processing region while forming a local plasma from the hydrogen-containing precursor;
forming cobalt chloride and amorphizing a portion of the cobalt by flowing a chlorine-containing precursor into the substrate processing region while forming a plasma from the chlorine-containing precursor to form chlorine-containing plasma effluents, wherein forming cobalt chloride and amorphizing the portion of the cobalt further comprises accelerating the chlorine-containing plasma effluents towards the substrate by biasing the plasma relative to the substrate, wherein forming the cobalt chloride occurs after removing the thin cobalt oxide layer;
purging the substrate processing region with an inert gas to remove the chlorine-containing precursor from the substrate processing region;
removing the cobalt from the substrate by flowing a carbon-and-nitrogen-containing precursor in to the substrate processing region, wherein the substrate processing region is plasma-free during the flowing of the carbon-and-nitrogen-containing precursor and flowing of the carbon-and-nitrogen-containing precursor occurs after purging the substrate processing region; and
transferring the substrate out of the substrate processing region.

2. The method of claim 1 wherein the substrate is maintained at a same substrate temperature during the removing the thin cobalt layer and removing the cobalt.

3. The method of claim 1 wherein the substrate remains inside the substrate processing throughout the method.

4. A method of etching cobalt from a substrate, the method comprising:
placing the substrate into a first substrate processing region, wherein the substrate comprises cobalt and an overlying cobalt oxide;
reducing the cobalt oxide and exposing the cobalt by flowing a hydrogen-containing precursor into a first substrate processing region housing the substrate while forming a hydrogen plasma in the substrate processing region;
placing the substrate into a second substrate processing region;
forming cobalt halide and amorphizing a portion of the cobalt by flowing a halogen-containing precursor into the second substrate processing region while forming a local plasma from the halogen-containing precursor to form halogen-containing plasma effluents, wherein forming the cobalt halide and amorphizing the portion of the cobalt further comprises accelerating the halogen-containing plasma effluents towards the substrate by biasing the plasma relative to the substrate;
flowing a carbon-and-nitrogen-containing precursor into the second substrate processing region, wherein the second substrate processing region is plasma-free during the flowing of the carbon-and-nitrogen-containing precursor and flowing of the carbon-and-nitrogen-containing precursor occurs after flowing the halogen-containing precursor;
removing cobalt from the substrate; and
removing the substrate from the second substrate processing region.

5. The method of claim 4 wherein the cobalt consists of cobalt.

6. The method of claim 4 wherein the hydrogen-containing precursor comprises H Z .

7. The method of claim 4 wherein the carbon-and-nitrogen-containing precursor comprises tetramethylethylenediamine.

8. The method of claim 4 wherein the carbon-and-nitrogen-containing precursor comprises a carbon-nitrogen single bond.

9. The method of claim 4 wherein the carbon-and-nitrogen-containing precursor comprises at least two methyl groups.

10. The method of claim 4 wherein the halogen-containing precursor comprises at least one of chlorine or bromine.

11. The method of claim 4 wherein the halogen-containing precursor is a homonuclear diatomic halogen.

12. The method of claim 4 wherein the first substrate processing region and the second substrate processing region are the same substrate processing region.

13. The method of claim 4 wherein the carbon-and-nitrogen-containing precursor consists of carbon, nitrogen and hydrogen.

14. The method of claim 4 wherein a pressure within the substrate processing region is between about 0.01 Torr and about 10 Torr during one or more of flowing the hydrogen-containing precursor, flowing the halogen-containing precursor or flowing the carbon-and-nitrogen-containing precursor.

15. The method of claim 4 wherein the cobalt halide is one of cobalt chloride or cobalt bromide.

16. The method of claim 4 wherein forming the plasma to treat the thin metal oxide layer comprises applying a local capacitive plasma RF power between a showerhead and the substrate.

17. The method of claim 4 wherein a processing temperature of the substrate is greater than 80° C. during the forming the cobalt halide and amorphizing the portion of the cobalt.

18. A method of etching cobalt from a substrate, the method comprising:
placing the substrate into a substrate processing region, wherein the substrate comprises exposed cobalt;
forming cobalt halide and amorphizing a portion of the cobalt by flowing a halogen-containing precursor into the substrate processing region while forming a local plasma from the halogen-containing precursor to form halogen-containing plasma effluents, wherein forming the cobalt halide and amorphizing the portion of the cobalt further comprises accelerating the halogen-containing plasma effluents towards the substrate by biasing the plasma relative to the substrate, and wherein the cobalt halide is formed from cobalt from the substrate and halogen from the halogen-containing precursor;
removing cobalt from the substrate by flowing a carbon-and-nitrogen-containing precursor into the (same) substrate processing region, wherein the substrate processing region is plasma-free during the flowing of the carbon-and-nitrogen-containing precursor and flowing of the carbon-and-nitrogen-containing precursor occurs after flowing the halogen-containing precursor; and
removing the substrate from the substrate processing region.

19. The method of claim 18 wherein a temperature of the substrate while removing the cobalt is between 80° C. and 600° C. during the removing cobalt from the substrate.

20. The method of claim 18 wherein the substrate is maintained at a same substrate temperature during the forming the cobalt halide and amorphizing the portion of the cobalt.

Assignees

• Applied Materials Inc

Inventors

• Wang Xikun
• Cui Zhenjiang
• Park Soonam
• Ingle Nitin K

Classifications

• H10P70/273

  the processing being a delineation of conductive layers, e.g. by RIE · CPC title

• H10P50/269

  pre- or post-treatments, e.g. anti-corrosion processes · CPC title

• H10P50/266

  by vapour etching only · CPC title

• H10P50/242

  of Group IV materials · CPC title

• H10W20/062

  by smoothing of conductive parts, e.g. by planarisation · CPC title