System, Method and Apparatus for Coordinating Pressure Pulses and RF Modulation in a Small Volume Confined Process Reactor

• US 20150060404A1
• Filed: 09/03/2013
• Published: 03/05/2015
• Est. Priority Date: 09/03/2013
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Dhindsa, Rajinder, Singh, Harmeet
• Granted Patent: US 9,184,029 B2
• Time in Patent Office: Days
• US Class Current: 216/61
• 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 37/32137 controlling of the discharge by modulation of energy
• CPC Class Codes: H01J 37/32449 Gas control, e.g. control of the gas flow
• CPC Class Codes: H01J 37/32532 Electrodes
• CPC Class Codes: H01J 37/32623 Mechanical discharge control means
• CPC Class Codes: H01J 37/32633 Baffles
• CPC Class Codes: H01J 37/32816 Pressure
• CPC Class Codes: H01J 37/32834 Exhausting

Abstract

A plasma processing system and method includes a processing chamber, and a plasma processing volume included therein. The plasma processing volume having a volume less than the processing chamber. The plasma processing volume being defined by a top electrode, a substrate support surface opposing the surface of the top electrode and a plasma confinement structure including at least one outlet port. A conductance control structure is movably disposed proximate to the at least one outlet port and capable of controlling an outlet flow through the at least one outlet port between a first flow rate and a second flow rate, wherein the conductance control structure controls the outlet flow rate and an at least one RF source is modulated and at least one process gas flow rate is modulated corresponding to a selected processing state set by the controller during a plasma process.

Claims

1. A plasma processing system comprising:

a processing chamber;

at least one gas source coupled to the processing chamber;

a controller coupled to the processing chamber and the at least one gas source;

the processing chamber including;

a top electrode disposed within a top portion of the processing chamber;

a substrate support disposed opposite from the top electrode;

a plasma processing volume having a volume less than a volume of the processing chamber, the plasma processing volume being defined by;

a surface of the top electrode;

a supporting surface of a substrate support opposing the surface of the top electrode; and

an outer perimeter defined by a plasma confinement structure, the plasma confinement structure including at least one outlet port;

at least one RF source coupled to at least one of the substrate support or the top electrode; and

a conductance control structure movably disposed proximate to the at least one outlet port, wherein the conductance control structure restricts an outlet flow through the at least one outlet port when disposed in a first position to a first flow rate and wherein the conductance control structure increases the outlet flow through the at least one outlet port when disposed in a second position to a second flow rate, wherein the conductance control structure moves between the first position and the second position corresponding to a selected processing state set by the controller during a plasma process and wherein the at least one RF source is modulated corresponding to the selected processing state set by the controller during the plasma process.

2. The system of claim 1, wherein the modulation of the at least one RF source is substantially in-phase with the selected processing state.

3. The system of claim 1, wherein the modulation of the at least one RF source is substantially 180 degrees out of phase with the selected processing state.

4. The system of claim 1, wherein the modulation of the at least one RF source lags the selected processing state.

5. The system of claim 1, wherein the modulation of the at least one RF source leads the selected processing state.

6. The system of claim 1, wherein the at least one RF source includes a high frequency RF source having an output of about 27 MHz.

7. The system of claim 1, wherein the at least one RF source includes a high frequency RF source having an output of about 60 MHz.

8. The system of claim 1, wherein the at least one RF source includes a high frequency RF source having an output of greater than about 27 MHz and low frequency RF source having an output of about 2 MHz.

9. The system of claim 1, wherein the controller coordinates an input flow rate of the at least one gas source into the processing volume with coordination of the movement of the conductance control structure and the modulation of the at least one RF source.

10. The system of claim 1, wherein the at least one outlet port in the plasma confinement structure is formed in a substantially horizontal portion of the plasma confinement structure.

11. The system of claim 1, wherein the at least one outlet port in the plasma confinement structure is formed in a substantially vertical portion of the plasma confinement structure.

12. A method of modulating a pressure in-situ in a plasma processing volume of a chamber, the plasma processing volume defined between a surface of a top electrode, a supporting surface of a substrate support and an outer region defined by a plasma confinement structure, the plasma confinement structure including at least one outlet port, the method comprising:

injecting at least one processing gas into the plasma processing volume;

forming a plasma within the plasma processing volume; and

modulating a pressure and modulating at least one RF source coupled to the plasma processing volume during a period of time when the plasma is formed in the plasma processing volume, the modulating of the pressure being controlled by at least one of,

a first outlet flow out of the plasma processing volume from the at least one outlet port, the first outlet flow being through a restricted flow path out of the at least one outlet port, or

a second outlet flow out of the plasma processing volume from the at least one outlet port, the second outlet flow being greater than the first outlet flow, wherein the second outlet flow being through a less restricted flow path out of the at least one outlet port than the first outlet flow.

13. The method of claim 12, wherein the period of time when the plasma is formed corresponds to a processing recipe having one or more predefined pressure set points and RF modulation set points.

14. The method of claim 13, wherein each of the predefined pressure set points corresponds to one of the first outlet flow or the second outlet flow or an outlet flow between the first outlet flow and second outlet flow.

15. The method of claim 12, wherein the pressure in the plasma processing volume is increased when the restriction of the conductance path is increased and the pressure in the plasma processing volume is decreased when the restriction of the conductance path is decreased.

16. The method of claim 12, wherein the modulation of the at least one RF source is substantially in-phase with the selected processing state.

17. The method of claim 12, wherein the modulation of the at least one RF source is substantially 180 degrees out of phase with the selected processing state.

18. The method of claim 12, wherein the modulation of the at least one RF source lags the selected processing state.

19. The method of claim 12, wherein the modulation of the at least one RF source leads the selected processing state.

20. A chamber, comprising,

a substrate support;

a top electrode;

at least one RF source coupled to at least one of the substrate support or the top electrode;

a confinement structure disposed to surround the substrate support, such that a plasma processing volume is defined between the substrate support, the top electrode and the confinement structure, the confinement structure includes a plurality of outlet ports that surround the substrate support; and

a conductance control structure disposed outside of the plasma processing volume and proximate to the plurality of outlet ports, the conductance control structure having a positioning actuator that provides movement of the conductance control structure between a first position and a second position, the first position placing the conductance control structure immediately adjacent to the plurality of outlet ports and the second position placing the conductance control structure in a location spaced away from the plurality of outlet ports and wherein the at least one RF source is modulated corresponding to the first position and the second position.

21. The chamber of claim 20, further comprising:

a controller, the controller being in communication with the positioning actuator to direct movement of the conductance control structure during one or more process states of a plasma processing recipe.

22. The chamber of claim 21, wherein the controller being in communication with a gas source that directs processing gases into the plasma processing chamber during the plasma processing recipe, such that the controller adjusts the conductance control structure between the first position and the second position or between the first and second positions as defined by the plasma processing recipe.