Tantalum-containing material removal

• US 10,727,080 B2
• Filed: 05/07/2018
• Issued: 07/28/2020
• Est. Priority Date: 07/07/2017
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Wang, Xikun, Yoshida, Naomi, Barman, Soumendra N., Ingle, Nitin K.
• Primary Examiner(s): Deo, Duy Vu N
• Application Number:
  US15/972,434
• Publication Number:
  US 20190013211A1
• Time in Patent Office: 813 Days
• CPC Class Codes: H01J 2237/002 Cooling arrangements of objects being observed or treated H01J2237/2001
• CPC Class Codes: H01J 2237/3341 Reactive etching
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01J 37/32165 Plural frequencies
• CPC Class Codes: H01J 37/32357 Generation remote from the workpiece, e.g. down-stream
• CPC Class Codes: H01J 37/32422 Arrangement for selecting ions or species in the plasma
• CPC Class Codes: H01J 37/32724 Temperature
• 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 21/31122 of layers not containing Si, e.g. PZT, Al2O3
• CPC Class Codes: H01L 21/32136 using plasmas
• CPC Class Codes: H01L 21/32137 of silicon-containing layers
• CPC Class Codes: H01L 21/67069 for drying etching
• CPC Class Codes: H01L 21/67167 surrounding a central transfer chamber

Abstract

Methods are described herein for etching tantalum-containing films with various potential additives while still retaining other desirable patterned substrate portions. The methods include exposing a tantalum-containing film to a chlorine-containing precursor (e.g. Cl₂) with a concurrent plasma. The plasma-excited chlorine-containing precursor selectively etches the tantalum-containing film and other industrially-desirable additives. Chlorine is then removed from the substrate processing region. A hydrogen-containing precursor (e.g. H₂) is delivered to the substrate processing region (also with plasma excitation) to produce a relatively even and residue-free tantalum-containing surface. The methods presented remove tantalum while retaining materials elsewhere on the patterned substrate.

Claims

1. A method of etching tantalum-containing material from a substrate, the method comprising:

placing the substrate into a substrate processing region, wherein the substrate comprises exposed tantalum-containing material, exposed titanium nitride, and exposed hafnium oxide;

etching the tantalum-containing material and the titanium nitride by flowing diatomic chlorine into the substrate processing region while forming a local plasma from the diatomic chlorine and forming chlorine plasma effluents, wherein etching the tantalum-containing material and the titanium nitride further comprises accelerating the chlorine plasma effluents towards the substrate by biasing the local plasma relative to the substrate, wherein etching the tantalum-containing material and the titanium-nitride leaves a residue on a remaining portion of the substrate, and wherein the hafnium oxide is substantially maintained during the etching;

removing the residue from the remaining portion of the substrate by flowing a hydrogen-containing precursor into the (same) substrate processing region while forming a hydrogen local plasma from the hydrogen-containing precursor to form hydrogen-containing plasma effluents, wherein flowing of the hydrogen-containing precursor occurs after flowing the diatomic chlorine; and

removing the substrate from the substrate processing region.

2. The method of claim 1 wherein the tantalum-containing material further comprises silicon, carbon, and aluminum.

3. The method of claim 1 wherein a temperature of the substrate while removing the tantalum-containing material is between 80°

C. and 450°

C. while removing tantalum-containing material from the substrate.

4. The method of claim 1 wherein the substrate is maintained at a same substrate temperature while etching the tantalum-containing material and removing the residue.

5. A method of etching tantalum-containing material from a substrate, the method comprising:

placing the substrate into a first substrate processing region, wherein the substrate comprises tantalum-containing material and an overlying tantalum oxide;

reducing the overlying tantalum oxide and exposing the tantalum-containing material and a titanium nitride by flowing a hydrogen-containing precursor into a first substrate processing region housing the substrate while forming a hydrogen plasma in the first substrate processing region;

placing the substrate into a second substrate processing region;

etching the tantalum-containing material and the titanium nitride by flowing a chlorine-containing precursor into the second substrate processing region while forming a local plasma from the chlorine-containing precursor to form chlorine-containing plasma effluents, wherein forming the local plasma further comprises accelerating the chlorine-containing plasma effluents towards the substrate by biasing the local plasma relative to the substrate, wherein the second substrate processing region is maintained between about 3 Torr and about 20 Torr during the etching;

flowing a hydrogen-containing precursor into the second substrate processing region while forming a second hydrogen plasma in the second substrate processing region, wherein flowing of the hydrogen-containing precursor occurs after flowing the chlorine-containing precursor; and

removing the substrate from the second substrate processing region.

6. The method of claim 5 wherein a temperature of the substrate while removing the tantalum-containing material is between 175°

C. and 275°

C. while removing tantalum-containing material from the substrate.

7. The method of claim 5 wherein the tantalum-containing material has at least 40% atomic percent tantalum.

8. The method of claim 5 wherein the tantalum-containing material has at least 50% atomic percent tantalum.

9. The method of claim 5 wherein the tantalum-containing material comprises tantalum, silicon, carbon and aluminum.

10. The method of claim 5 wherein the hydrogen-containing precursor comprises Hz.

11. The method of claim 5 wherein the first substrate processing region and the second substrate processing region are the same substrate processing region.

12. The method of claim 5 wherein a pressure within the first substrate processing region and the second substrate processing region is between 0.01 Torr and 10 Torr during one or more of flowing the hydrogen-containing precursor, flowing the halogen-containing precursor or flowing the hydrogen-containing precursor.

13. The method of claim 5 wherein forming the hydrogen plasma comprises applying a local capacitive plasma RF power between a showerhead and the substrate.

14. The method of claim 5 wherein a processing temperature of the substrate is greater than 80°

C. during the etching of the tantalum-containing material.

15. A method of etching tantalum-containing material and tantalum oxide, the method comprising:

transferring a substrate into a substrate processing region, wherein the substrate comprises tantalum-containing material and a thin tantalum oxide layer thereon;

removing the thin tantalum oxide layer by flowing a hydrogen-containing precursor into the substrate processing region while forming a local plasma from the hydrogen-containing precursor;

etching the tantalum-containing material and an exposed titanium nitride by flowing a chlorine-containing precursor into the substrate processing region while forming a chlorine plasma from the chlorine-containing precursor to form chlorine-containing plasma effluents, wherein etching the tantalum-containing material occurs after removing the thin tantalum oxide layer, wherein removing the tantalum-containing material leaves a residue on a post-etch surface of the tantalum-containing material, wherein the substrate processing region is maintained at a pressure between about 3 Torr and about 20 Torr during the etching, wherein the substrate further comprises an exposed hafnium oxide, and wherein the exposed hafnium oxide is substantially maintained during the etching;

removing the chlorine-containing precursor by purging the substrate processing region with an inert gas;

removing the residue from the post-etch surface by flowing a second hydrogen-containing precursor into the substrate processing region while forming a second local plasma from the second hydrogen-containing precursor; and

transferring the substrate out of the substrate processing region.

16. The method of claim 15 wherein forming a chlorine plasma comprises accelerating the chlorine-containing plasma effluents towards the substrate by biasing the chlorine plasma relative to the substrate.

17. The method of claim 15 wherein the substrate is maintained at a same substrate temperature during the removal of the thin tantalum oxide layer and the removal of the tantalum-containing material.

18. The method of claim 15 wherein the substrate remains inside the substrate processing region throughout the method.