Enhanced etching processes using remote plasma sources

• US 10,424,485 B2
• Filed: 06/06/2016
• Issued: 09/24/2019
• Est. Priority Date: 03/01/2013
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Ingle, Nitin K., Lubomirsky, Dmitry, Chen, Xinglong, Venkataraman, Shankar
• Primary Examiner(s): Olsen, Allan W.
• Application Number:
  US15/173,824
• Publication Number:
  US 20160284556A1
• Time in Patent Office: 1,205 Days
• Field of Search: None
• CPC Class Codes: H01J 2237/334 Etching
• CPC Class Codes: H01J 37/32082 Radio frequency generated discharge H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence
• CPC Class Codes: H01J 37/32357 Generation remote from the workpiece, e.g. down-stream
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32449 Gas control, e.g. control of the gas flow
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching

Abstract

Methods of etching a patterned substrate may include flowing an oxygen-containing precursor into a first remote plasma region fluidly coupled with a substrate processing region. The oxygen-containing precursor may be flowed into the region while forming a plasma in the first remote plasma region to produce oxygen-containing plasma effluents. The methods may also include flowing a fluorine-containing precursor into a second remote plasma region fluidly coupled with the substrate processing region while forming a plasma in the second remote plasma region to produce fluorine-containing plasma effluents. The methods may include flowing the oxygen-containing plasma effluents and fluorine-containing plasma effluents into the processing region, and using the effluents to etch a patterned substrate housed in the substrate processing region.

Claims

1. A method of etching a patterned substrate, the method comprising:

flowing an oxygen-containing precursor into a remote plasma system (RPS) unit fluidly coupled with a substrate processing region while forming a plasma in the RPS unit to produce oxygen-containing plasma effluents;

flowing an unexcited fluorine-containing precursor through an inlet assembly coupled with the RPS unit, wherein the fluorine-containing precursor bypasses the RPS unit and flows into a second remote plasma region fluidly coupled in series between the RPS unit and the substrate processing region while forming a plasma in the second remote plasma region to produce fluorine-containing plasma effluents in the second remote plasma region;

flowing the oxygen-containing plasma effluents into the second remote plasma region;

flowing the oxygen-containing plasma effluents and fluorine-containing plasma effluents together into the processing region; and

etching a patterned substrate housed in the substrate processing region with the oxygen-containing and fluorine-containing plasma effluents.

2. The method of claim 1, wherein at least one additional precursor is flowed with one or both of the oxygen-containing precursor or the fluorine-containing precursor, and the additional precursor is selected from the group consisting of helium, argon, nitrogen, and molecular hydrogen (H₂).

3. The method of claim 1, wherein the fluorine-containing precursor comprises a precursor selected from the group consisting of atomic fluorine, diatomic fluorine, nitrogen trifluoride, carbon tetrafluoride, hydrogen fluoride, and xenon difluoride.

4. The method of claim 3, wherein the fluorine-containing precursor comprises nitrogen trifluoride, and wherein the fluorine-containing plasma effluents consist essentially of NF* and NF₂* species.

5. The method of claim 1, wherein the oxygen-containing precursor comprises a precursor selected from the group consisting of molecular oxygen, ozone, nitrous oxide, nitric oxide, and nitrogen dioxide.

6. The method of claim 1, wherein the second remote plasma region is configured to produce a capacitively-coupled plasma.

7. The method of claim 6, wherein the plasma in the second remote plasma region is operated at a power level of less than or about 200 Watts.

8. The method of claim 1, wherein the fluorine-containing precursor bypasses the first plasma region.

9. The method of claim 1, wherein the substrate temperature is maintained at or below about 50°

C. during the etch process.

10. A method of etching a patterned substrate, the method comprising:

flowing an oxygen-containing precursor into a remote plasma system (RPS) unit fluidly coupled with a second remote plasma region of a substrate processing chamber while forming a plasma in the RPS unit to produce oxygen-containing plasma effluents;

delivering the oxygen-containing plasma effluents into the second remote plasma region;

flowing an unexcited fluorine-containing precursor through an inlet assembly coupled with the RPS unit, wherein the fluorine-containing precursor bypasses the RPS unit and flows into the second remote plasma region while forming a plasma in the second remote plasma region to produce fluorine-containing plasma effluents, wherein the second remote plasma region is fluidly coupled with a substrate processing region;

delivering the oxygen-containing plasma effluents and fluorine-containing plasma effluents into the substrate processing region; and

etching a patterned substrate housed in the substrate processing region with the oxygen-containing and fluorine-containing plasma effluents.

11. The method of claim 10, wherein the plasma in the second remote plasma region is a capacitively-coupled plasma.

12. The method of claim 11, wherein the plasma in the second remote plasma region is operated at a power level of less than or about 200 Watts.

13. The method of claim 10, wherein the first remote plasma region is operated at a first plasma power and the second remote plasma region is operated at a second plasma power, and wherein the first plasma power and second plasma power are different from one another.