Methods for etching materials using synchronized RF pulses

• US 9,269,587 B2
• Filed: 09/06/2013
• Issued: 02/23/2016
• Est. Priority Date: 09/06/2013
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Shimizu, Daisuke, Kim, Jong Mun, Kawasaki, Katsumasa, Shoji, Sergio Fukuda
• Primary Examiner(s): Ahmed, Shamim
• Application Number:
  US14/020,773
• Publication Number:
  US 20150072530A1
• Time in Patent Office: 900 Days
• Field of Search: 216/67, 216/79, 438/710, 438/719, 438/723
• US Class Current: 1/1
• CPC Class Codes: H01J 2237/334 Etching
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/31116 by dry-etching

Abstract

Embodiments of the present invention provide methods for etching a material layer using synchronized RF pulses. In one embodiment, a method includes providing a gas mixture into a processing chamber, applying a first RF source power at a first time point to the processing chamber to form a plasma in the gas mixture, applying a first RF bias power at a second time point to the processing chamber to perform an etching process on the substrate, turning off the first RF bias power at a third time point while continuously maintaining the first RF source power on from the first time point through the second and the third time points, and turning off the first RF source power at a fourth time point while continuously providing the gas mixture to the processing chamber from the first time point through the second, third and fourth time points.

Claims

1. A method of etching a material layer disposed on a substrate using synchronized RF pulses comprising:

providing a gas mixture into a processing chamber having a substrate disposed therein;

applying a first RF source power at a first time point to the processing chamber to form a plasma in the gas mixture;

applying a first RF bias power at a second time point and a third time point to the processing chamber to perform an etching process on the substrate while continuously applying the first RF source power in the processing chamber from the first time point through the second and the third time points;

applying a second RF bias power at the second time point while continuously applying the first RF bias power and the first RF source power in the processing chamber;

turning off the second RF bias power at the third time point applied to the processing chamber while continuously maintaining the first RF source and the first RF bias power on from the second time point through the third time points; and

turning off the first RF source power and the first RF bias power at a fourth time point applied to the processing chamber while continuously providing the gas mixture to the processing chamber from the first time point through the second, third and fourth time points.

2. The method of claim 1, further comprising:

applying a preliminary RF source power to the processing chamber prior to applying the first RF source power in the gas mixture.

3. The method of claim 2, wherein applying the preliminary RF source power further comprises:

applying a preliminary RF bias power to the processing chamber while applying the preliminary RF source power.

4. The method of claim 1, wherein applying the first RF source power at the first time point further comprises:

applying the first RF source power for a first time period between about 1 microseconds and about 4000 microseconds.

5. The method of claim 1, wherein applying the first RF source power at the first time point further comprises:

performing a pre-coating process to form a pre-coating layer on the substrate.

6. The method of claim 1, wherein applying the first RF bias power at the second time point further comprises:

applying the first RF bias power between about 10 microseconds and about 8800 microseconds.

7. The method of claim 1, wherein turning off the second RF bias power at the third time point further comprises:

continuously applying the first RF source power for between about 1 microseconds and about 4000 microseconds.

8. The method of claim 7, wherein continuously applying the first RF source power in the processing chamber further comprises:

performing a post-coating process to form a post-coating layer on the substrate.

9. The method of claim 1, wherein continuously supplying the gas mixture into the processing chamber for at fourth time period comprises supplying the gas mixture for between about 10 microseconds and about 8800 microseconds.

10. The method of claim 9, further comprising:

performing a pump/purge process in the processing chamber while continuously supplying the gas mixture.

11. The method of claim 9, wherein the gas mixture continuously supplied to the processing chamber during the fourth time period includes an inert gas or a carrier gas.

12. The method of claim 1, wherein the gas mixture includes at least a fluorine based gas and a polymer-rich carbon containing gas.

13. The method of claim 1, wherein the first RF source power has a frequency of about 162 MHz.

14. The method of claim 1, wherein the first RF bias power has a frequency of about 60 MHz.

15. The method of claim 1, wherein the step of the applying the first RF source power at the first time point and the step of applying the first RF bias power and the second RF bias power at the second time point are repeatedly performed.

16. A method for etching a material layer disposed on a substrate comprising:

performing a pre-coating process on a substrate by supplying a gas mixture into a processing chamber and forming a plasma from the gas mixture by applying a first RF source power in the gas mixture;

performing an etching process on the substrate by applying a first RF bias power and a second RF bias power into the processing chamber while continuously applying the first RF source power in the processing chamber; and

performing a post-coating process on the substrate by turning off the first RF bias power and a second RF bias power applied into the processing chamber while continuously applying the first RF source power in the processing chamber, wherein the second RF bias power is turned off prior to the first RF bias power.

17. The method of claim 16, further comprising:

performing a pump/purge process in the processing chamber while turning off the first RF source power but continuously supplying the gas mixture into the processing chamber.

18. The method of claim 16, wherein the substrate includes a material layer disposed thereon, wherein the material layer is a silicon oxide layer, silicon nitride, alphamos silicon, or a composite layer including silicon oxide and polysilicon or silicon oxide and silicon nitride.

19. The method of claim 16, wherein the gas mixture includes at least a fluorine based gas and a polymer-rich carbon containing gas.