System, Method and Apparatus for Generating Pressure Pulses in Small Volume Confined Process Reactor

• US 20150064920A1
• Filed: 08/28/2013
• Published: 03/05/2015
• Est. Priority Date: 08/28/2013
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Dhindsa, Rajinder, Singh, Harmeet, Nam, Sang Ki
• Granted Patent: US 9,330,927 B2
• Time in Patent Office: Days
• US Class Current: 438/714
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01J 37/32449 Gas control, e.g. control of the gas flow
• CPC Class Codes: H01J 37/32816 Pressure
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/67069 for drying etching

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 restricting an outlet flow through the at least one outlet port to a first flow rate and capable of increasing the outlet flow through the at least one outlet port to a second flow rate, wherein the conductance control structure restricts the outlet flow rate moves between the first flow rate and the second flow rate 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; 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.

2. The system of claim 1, wherein the conductance control structure in the first position increases a pressure in the plasma processing volume, and the conductance control structure in the second position decreases the pressure in the plasma processing volume.

3. The system of claim 2, wherein the controller sets a plurality of positions of the conductance control structure between the first and second positions, each of the plurality of positions of the conductance control structure corresponding to a selected outlet flow rate through the at least one outlet port that is between the first flow rate and the second flow rate.

4. The system of claim 2, 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.

5. The system of claim 1, wherein the conductance control structure includes at least one opening corresponding to the at least one outlet port in the plasma confinement structure.

6. The system of claim 1, wherein the conductance control structure includes a plurality of substantially equally distributed openings.

7. The system of claim 1, wherein the conductance control structure includes a plurality of unequally distributed openings.

8. The system of claim 1, further comprising at least one RF source coupled to the processing chamber.

9. The system of claim 1, further comprising at least one RF source coupled to the processing chamber, wherein the at least one RF source includes a first operational state corresponding to the first position of the conductance control structure and a second operational state corresponding to the second position of the conductance control structure.

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 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 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.

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 processing chamber remains at a substantially constant pressure equal to the first pressure.

17. The method of claim 12, further comprising changing an operational state of at least one RF source coupled to the processing chamber to correspond to at least one of the first pressure or the second pressure.

18. A chamber, comprising,

a substrate support, a 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.

19. The chamber of claim 18, wherein the movement is along a vertical orientation, wherein the substrate support is oriented in a horizontal orientation.

20. The chamber of claim 18, wherein the conductance control structure is a ring structure connected to the positioning actuator.