MIXED MODE PULSING ETCHING IN PLASMA PROCESSING SYSTEMS

• US 20150020971A1
• Filed: 10/09/2014
• Published: 01/22/2015
• Est. Priority Date: 12/28/2011
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Kanarik, Keren Jacobs
• Granted Patent: US 9,425,025 B2
• Time in Patent Office: Days
• US Class Current: 156/345.26
• 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 37/32146 Amplitude modulation, includes pulsing
• CPC Class Codes: H01J 37/32155 Frequency modulation
• CPC Class Codes: H01J 37/32174 Circuits specially adapted for controlling the RF discharge
• CPC Class Codes: H01J 37/32449 Gas control, e.g. control of the gas flow

Abstract

A method for processing substrate in a chamber, which has at least one plasma generating source, a reactive gas source for providing reactive gas into the interior region of the chamber, and a non-reactive gas source for providing non-reactive gas into the interior region, is provided. The method includes performing a mixed-mode pulsing (MMP) preparation phase, including flowing reactive gas into the interior region and forming a first plasma to process the substrate that is disposed on a work piece holder. The method further includes performing a MMP reactive phase, including flowing at least non-reactive gas into the interior region, and forming a second plasma to process the substrate, the second plasma is formed with a reactive gas flow during the MMP reactive phase that is less than a reactive gas flow during the MMP preparation phase. Perform the method steps a plurality of times.

Claims

1. A plasma processing system for processing a substrate using mixed-mode pulsing, the plasma processing system comprising:

a substrate;

a plasma processing chamber for processing the substrate;

a work piece holder within an interior region of the plasma processing chamber;

at least one plasma generating source;

at least one reactive gas source for providing at least a first reactive gas into the interior region of the plasma processing chamber;

at least one non-reactive gas source for providing at least a first non-reactive gas into the interior region of the plasma processing chamber; and

a tangible computer-readable medium storing computer-readable instructions for;

(a) disposing the substrate on the work piece holder within the interior region;

(b) performing a mixed-mode pulsing (MMP) preparation phase, including flowing the first reactive gas into the interior region,

exciting the first reactive gas with a first RF signal having a first RF frequency, the first RF signal representing an RF signal having chirped frequencies, and

forming a first plasma with at least the first reactive gas to process the substrate with the first plasma;

(c) performing a mixed mode pulsing (MMP) reactive phase, including flowing at least the first non-reactive gas into the interior region, and

forming a second plasma with at least the first non-reactive gas to process the substrate with the second plasma, wherein the second plasma is formed with a flow of the first reactive gas during the MMP reactive phase that is less than a flow of the first reactive gas during the MMP preparation phase; and

(d) repeating steps (b) and (c) for a plurality of times.

2. The system of claim 1 further comprising computer-readable instructions for providing that no first reactive gas is flowed into the interior region during the MMP reactive phase.

3. The system of claim 1 wherein the plasma processing chamber comprises an inductively coupled plasma processing chamber.

4. The system of claim 1 wherein the plasma processing chamber comprises a capacitively coupled plasma processing chamber.

5. The system of claim 1 wherein the at least one non-reactive gas source further provides a second non-reactive gas, and wherein the tangible computer-readable medium further comprises storing computer-readable instructions for providing that the second non-reactive gas is flowed into the interior region during the MMP preparation phase.

6. The system of claim 1 further comprising computer-readable instructions for providing that the first non-reactive gas is also flowed into the interior region during the MMP preparation phase.

7. The system of claim 1 further comprising computer-readable instructions for providing that no bias power is applied to the work piece holder during the MMP preparation phase.

8. The system of claim 7 further comprising computer-readable instructions for providing that bias power having a bias power level greater than zero is applied to the work piece holder during the MMP reactive phase.

9. The system of claim 1 further comprising computer-readable instructions for flowing a second reactive gas different from the first reactive gas into the interior region during the MMP reactive phase.

10. The system of claim 9 further comprising computer-readable instructions for providing that no first reactive gas is flowed during the MMP reactive phase.

11. The system of claim 1 further comprising computer-readable instructions for providing that a first bias power is applied to the work piece holder during the MMP preparation phase and a second bias power having a different power level from a power level of the first bias power is applied to the work piece holder during the MMP reactive phase.

12. The system of claim 11 further comprising computer-readable instructions for providing that the power level of the second bias power is higher than the power level of the first bias power.

13. The system of claim 1 further comprising computer-readable instructions for providing that the plasma processing chamber is configured during the MMP reactive phase to generate non-reactive ions having a level of ion energy that is higher than required to etch an adsorbed layer on a surface of the substrate but insufficient to etch a non-adsorbed layer of the substrate, and providing that the adsorbed layer formed during the MMP preparation phase.

14. A plasma processing system for processing a substrate using mixed-mode pulsing, the plasma processing system comprising:

a substrate;

a plasma processing chamber for processing the substrate;

a work piece holder within an interior region of the plasma processing chamber;

at least one plasma generating source;

at least one reactive gas source for providing at least a first reactive gas into the interior region of the plasma processing chamber;

at least one non-reactive gas source for providing at least a first non-reactive gas into the interior region of the plasma processing chamber; and

a tangible computer-readable medium storing computer-readable instructions for;

(a) disposing the substrate on a work piece holder within the interior region;

(b) performing a mixed-mode pulsing (MMP) preparation phase, including flowing the first reactive gas into the interior region, and

forming a first plasma with at least the first reactive gas to process the substrate with the first plasma;

(c) performing a mixed mode pulsing (MMP) reactive phase, including flowing at least the first non-reactive gas into the interior region, and

forming a second plasma with at least the first non-reactive gas to process the substrate with the second plasma, wherein the second plasma is formed with a flow of the first reactive gas during the MMP reactive phase that is less than a flow of the first reactive gas during the MMP preparation phase, wherein the plasma processing chamber is configured during the MMP reactive phase to generate non-reactive ions having a level of ion energy that is higher than required to etch an adsorbed layer on a surface of the substrate but insufficient to etch a non-adsorbed layer of the substrate, the adsorbed layer formed during the MMP preparation phase; and

(d) repeating steps (b) and (c) for a plurality of times.

15. The system of claim 14 further comprising computer-readable instructions for providing that no first reactive gas is flowed into the interior region during the MMP reactive phase.

16. The system of claim 14 further comprising computer-readable instructions for providing that no bias power is applied to the work piece holder during the MMP preparation phase.

17. The system of claim 16 further comprising computer-readable instructions for providing that bias power having a bias power level greater than zero is applied to the work piece holder during the MMP reactive phase.

18. The system of claim 17 further comprising computer-readable instructions for providing that the bias power is pulsed during the MMP reactive phase.

19. The system of claim 14 further comprising at least one inductive antenna, and further comprising computer-readable instructions for providing that the at least one inductive antenna is excited with a first RF signal having a first RF frequency during the MMP preparation phase, and the at least one inductive antenna is excited with a second RF signal having a second RF frequency that is different from the first RF frequency during the MMP reactive phase.

20. The system of claim 14 further comprising at least one inductive antenna, and further comprising computer-readable instructions for providing that the at least one inductive antenna is excited with a first RF signal having a first RF frequency during the MMP preparation phase, the first RF signal representing a pulsed RF signal.

21. The system of claim 14 further comprising at least one inductive antenna, and further comprising computer-readable instructions for providing that the at least one inductive antenna is excited with a first RF signal having a first RF frequency during the MMP reactive phase, the first RF signal representing a pulsed RF signal.

22. A plasma processing system for processing a substrate using mixed-mode pulsing, the plasma processing system comprising:

a substrate;

a plasma processing chamber for processing the substrate;

a work piece holder within an interior region of the plasma processing chamber;

at least one reactive gas source for providing at least a first reactive gas into the interior region of the plasma processing chamber;

at least one non-reactive gas source for providing at least a first non-reactive gas into the interior region of the plasma processing chamber;

at least one gas pulsing valve for flowing a first reactive gas into the interior region during a mixed-mode pulsing (MMP) preparation phase;

at least one gas pulsing valve for flowing a first non-reactive gas into the interior region during a mixed-mode pulsing (MMP) reactive phase, wherein the flow of the first reactive gas during the MMP reactive phase is less than a flow of the first reactive gas during the MMP preparation phase; and

at least one plasma generating source comprising a pulse-capable RF power supply for;

during the MMP preparation phase, exciting the first reactive gas with a first RF signal having a first RF frequency, the first RF signal representing an RF signal having chirped frequencies, and forming a first plasma with at least the first reactive gas to process the substrate with the first plasma; and

during the MMP reactive phase, forming a second plasma with at least the first non-reactive gas to process the substrate with the second plasma, wherein the MMP preparation phase and the MMP reactive phase are alternated and repeated for a plurality of times.

23. The system of claim 22 wherein no first reactive gas is flowed into the interior region during the MMP reactive phase.

24. The system of claim 22 wherein the plasma processing chamber comprises an inductively coupled plasma processing chamber.

25. The system of claim 22 wherein the plasma processing chamber comprises a capacitively coupled plasma processing chamber.

26. The system of claim 22 wherein the at least one non-reactive gas source further provides a second non-reactive gas, and wherein the second non-reactive gas is flowed into the interior region during the MMP preparation phase.

27. The system of claim 22 wherein the first non-reactive gas is also flowed into the interior region during the MMP preparation phase.

28. The system of claim 22 wherein no bias power is applied to the work piece holder during the MMP preparation phase.

29. The system of claim 28 wherein bias power having a bias power level greater than zero is applied to the work piece holder during the MMP reactive phase.

30. The system of claim 22 wherein a second reactive gas different from the first reactive gas is flowed into the interior region during the MMP reactive phase.

31. The system of claim 30 further comprising wherein no first reactive gas is flowed during the MMP reactive phase.

32. The system of claim 22 wherein a first bias power is applied to the work piece holder during the MMP preparation phase and a second bias power having a different power level from a power level of the first bias power is applied to the work piece holder during the MMP reactive phase.

33. The system of claim 32 further comprising wherein the power level of the second bias power is higher than the power level of the first bias power.

34. The system of claim 22 wherein the plasma processing chamber is configured during the MMP reactive phase to generate non-reactive ions having a level of ion energy that is higher than required to etch an adsorbed layer on a surface of the substrate but insufficient to etch non-adsorbed layer of the substrate, and providing that the adsorbed layer is formed during the MMP preparation phase.