Sensor array for measuring plasma characteristics in plasma processing environments

• US 20050151544A1
• Filed: 02/25/2005
• Published: 07/14/2005
• Est. Priority Date: 08/14/2003
• Status: Active Grant

• Current Assignee: KLA-Tencor Corporation
• Original Assignee: Advanced Energy Industries Incorporated
• Inventors: Walde, Hendrik V., Mahoney, Leonard J., Roche, Gregory A., Almgren, Carl W., Sproul, William D., Saylor, William W.
• Granted Patent: US 8,545,669 B2
• Time in Patent Office: Days
• US Class Current: 324/655
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H01J 37/32954 Electron temperature measurement

Abstract

A plasma processing system is provided with diagnostic apparatus for making in-situ measurements of plasma properties. The diagnostic apparatus generally comprises a non-invasive sensor array disposed within a plasma processing chamber, an electrical circuit for stimulating the sensors, and means for recording and communicating sensor measurements for monitoring or control of the plasma process. In one form, the sensors are dynamically pulsed dual floating Langmuir probes that measure incident charged particle currents and electron temperatures in proximity to the plasma boundary or boundaries within the processing system. The plasma measurements may be used to monitor the condition of the processing plasma or furnished to a process system controller for use in controlling the plasma process.

Claims

1-18. -18. (canceled)

19. A method of measuring plasma properties in a plasma processing system, comprising:

a) providing a plasma processing system having a plasma chamber;

b) providing a sensor array comprising a plurality of electrically floating sensors disposed within the plasma chamber;

c) generating a plasma within the plasma chamber for use in a plasma process; and

d) measuring bulk properties of the plasma using the sensor array.

20. The method of claim 19 wherein the sensors are dual floating Langmuir probes.

21. The method of claim 19 wherein the array of dual floating Langmuir probes comprises a common electron return current pad.

22. The method of claim 19 wherein the sensor array is disposed along a chamber liner contained within the plasma chamber.

23. The method of claim 19 wherein the sensor array is disposed along a dielectric isolation ring contained within the plasma chamber.

24. The method of claim 19 wherein the sensor array is disposed along a focus ring contained within the plasma chamber.

25. The method of claim 19 wherein the sensor array is disposed about a workpiece chuck contained within the plasma chamber.

26. The method of claim 19 wherein the bulk properties of the plasma are measured in real time.

27. The method of claim 19 wherein the plurality of sensors is dynamically pulsed to measure bulk properties of the plasma.

28. The method of claim 27 wherein the plasma is created using a pulsed power source and the dynamic pulsing of the plurality of sensors is synchronized with the pulsing of the pulsed power source.

29. The method of claim 19, further comprising the step of transmitting the measured properties of the plasma outside the plasma process.

30. The method of claim 29 wherein the measured properties of the plasma are transmitted wirelessly outside the plasma process.

31. The method of claim 19, further comprising the step of furnishing the measured properties of the plasma to a process system controller that controls the plasma process.

32. A system for measuring plasma properties in a plasma processing system, comprising:

a) a sensor array disposed about a boundary of a processing region of a plasma processing system, the sensor array comprising a plurality of electrically floating sensors;

b) a circuit for stimulating the sensor array to measure properties of a processing plasma within the plasma chamber; and

c) a circuit for communicating properties of the plasma measured by the sensor array.

33. The apparatus of claim 32 wherein the sensors are dual floating Langmuir probes.

34. The system of claim 33 wherein the array of dual floating Langmuir probes comprises a common electron return current pad.

35. The system of claim 32 wherein the sensor array is disposed along a chamber liner contained within the plasma chamber.

36. The system of claim 32 wherein the sensor array is disposed along a dielectric isolation ring contained within the plasma chamber.

37. The system of claim 32 wherein the sensor array is disposed along a focus ring contained within the plasma chamber.

38. The system of claim 32 wherein the sensor array is disposed about a workpiece chuck contained within the plasma chamber.

39. The apparatus of claim 32 wherein the sensors are removable from the plasma processing system.

40. The apparatus of claim 32 wherein the sensor array measures bulk properties of the processing plasma.

41. The system of claim 32 wherein the circuit for stimulating the plurality of sensors is a dynamic pulsing circuit.

42. The system of claim 32 wherein the circuit for stimulating the plurality of sensors is a multiplex circuit.

42-1. The system of claim 32 wherein the circuit for communicating properties of the plasma is disposed to transmit the measured properties of the plasma wirelessly outside the plasma process.