Method and apparatus for processing a workpiece with a plasma

• US 20040219737A1
• Filed: 06/03/2004
• Published: 11/04/2004
• Est. Priority Date: 12/20/2001
• Status: Abandoned Application

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Quon, Bill H.
• Application Number:
  US10/859,129
• Publication Number:
  US 20040219737A1
• Time in Patent Office: Days
• US Class Current: 438/222
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/32357 Generation remote from the workpiece, e.g. down-stream
• CPC Class Codes: H01J 37/32623 Mechanical discharge control means
• CPC Class Codes: H01J 37/3266 Magnetic control means
• CPC Class Codes: H01J 37/32697 Electrostatic control
• CPC Class Codes: H01J 37/32954 Electron temperature measurement

Abstract

A plasma processing apparatus includes a source gas injection device to inject a gaseous source material into a source region of the apparatus, a plasma generating device to transmit energy to the source material to generate a source plasma, and a process gas injection device to inject a gaseous process material into a process region of the apparatus. A magnetic filter assembly imposes a magnetic field generally between the source and process regions to control the flow of charged particles from the source plasma into the gaseous process material to generate a process plasma in the process region. A source electrode in contact with the source plasma controls the potential of the source plasma. An electrode supports a workpiece and generates a potential to attract charged particles from the process plasma toward the workpiece so that the charged particles strike the workpiece.

Claims

1. A plasma processing apparatus for processing a workpiece, the apparatus comprising:

a source gas injection device constructed and arranged to inject a gaseous source material into a source region of said apparatus;

a plasma generating device mounted in plasma generating relation to said source region and being constructed and arranged to transmit energy to a gaseous source material in said source region to generate a source plasma;

a process gas injection device constructed and arranged to inject a gaseous process material into a process region of said apparatus;

a magnetic filter assembly constructed and arranged to impose a magnetic field generally between said source region and said process region to control the flow of charged particles from the source plasma into the gaseous process material to generate a process plasma in said process region;

a source electrode in contact with the source plasma constructed and arranged to control the potential of the source plasma; and

a support structure constructed and arranged to support a workpiece so that the charged particles strike the workpiece.

2. A plasma processing apparatus as recited in claim 1, wherein said support structure comprises an electrode constructed and arranged to support said workpiece and to generate a potential to attract charged particles from the process plasma toward the workpiece so that the charged particles strike the workpiece.

3. A plasma processing apparatus as recited in claim 1, wherein said plasma generating device includes an inductive coil.

4. A plasma processing apparatus as recited in claim 3, wherein said inductive coil is a TCP coil mounted in plasma generating relation to the source region of said apparatus.

5. A plasma processing apparatus as recited in claim 4, wherein said plasma generating device further includes a power supply in electrical communication with said coil.

6. A plasma processing apparatus as recited in claim 3, wherein said source gas injection device is a substantially annular gas injector mounted about the periphery of said plasma TCP coil.

7. A plasma processing apparatus as recited in claim 6, wherein said process gas injection device is disposed between said magnetic filter assembly and said process region of said apparatus.

8. A plasma processing apparatus as recited in claim 1, wherein said process gas injection device includes a plurality of tubes, each tube including one or more gas outlet openings and said tubes being coupled to a source of said gaseous process material.

9. A plasma processing apparatus as recited in claim 1, wherein said magnetic filter assembly includes an array of permanent magnets.

10. A plasma processing apparatus as recited in claim 9, wherein each permanent magnet is contained within a housing made of at least one of a metal and a dielectric material.

11. A plasma processing apparatus as recited in claim 10, wherein said metal material is aluminum.

12. A plasma processing apparatus as recited in claim 1, wherein said magnetic filter assembly includes one or more electromagnets.

13. A plasma processing apparatus as recited in claim 12, wherein said magnetic filter assembly is comprised of a U-shaped electromagnet having a bight portion and a pair of leg portions extending from the bight portion, the magnetic filter assembly further including an array of permanent magnets connected to said bight portion and extending outwardly therefrom in spaced relation to the leg portions.

14. A plasma processing apparatus as recited in claim 13, said U-shaped electromagnet comprising a U-shaped yoke constructed of a magnetic flux conducting material and defining said bight and leg portions and further comprising one or more coil magnets wound around the bight portion of the electromagnet such that when each said one or more coil magnets is energized, magnetic energy is generated and conducted through said yoke.

15. A plasma processing apparatus as recited in claim 14, further comprising one or more current sources, each said one or more coil magnet being in electrical communication with a current source.

16. A plasma processing apparatus for processing a workpiece, the apparatus comprising:

a reaction chamber having an interior that defines a source region and a processing region;

a source gas injection device constructed and arranged to inject a gaseous source material into said source region of said reaction chamber;

a plasma generating device mounted to said chamber and being constructed and arranged to transmit energy to a gaseous source material in said source region to generate a source plasma;

a process gas injection device constructed and arranged to inject a gaseous process material into said process region of said reaction chamber;

a voltage source in contact with the source plasma constructed and arranged to control the potential of the source plasma;

a magnetic filter assembly constructed and arranged to impose a magnetic field generally between said source region and said process region to control the flow of charged particles from the source plasma into the gaseous process material to generate a process plasma in said process region; and

a support structure constructed and arranged to support a workpiece so that the charged particles strike the workpiece.

17. A plasma processing apparatus as recited in claim 16, said support structure comprising an electrode constructed and arranged to support the workpiece and to generate a potential to attract charged particles from the process plasma toward the workpiece so that the charged particles strike the workpiece.

18. A plasma processing apparatus as recited in claim 16, wherein said plasma generating device includes a spiral RF antenna in electrical communication with one or more RF power sources and inductively coupled to said gaseous source material.

19. A plasma processing apparatus as recited in claim 18, wherein said RF antenna is mounted on a dielectric window to facilitate transmission of energy to a gaseous source material in said source region to generate a source plasma.

20. A plasma processing apparatus as recited in claim 16, wherein said reaction chamber includes one or more grounded side wall portions at least partially surrounding said source region and said processing region.

21. A plasma processing apparatus as recited in claim 20, wherein said reaction chamber is made of a metal material.

22. A plasma processing apparatus as recited in claim 21, wherein said metal material is aluminum.

23. A plasma processing apparatus as recited in claim 16, wherein said voltage source is positioned between said source region and said magnetic filter assembly and wherein said voltage source includes a plurality of openings constructed and arranged to allow passage of charged particles from a source plasma in said source region to said processing region.

24. A plasma processing apparatus as recited in claim 23, wherein said magnetic filter assembly includes an array of permanent magnets, the array of magnets being spaced with one another so as to define a plurality of openings in said magnetic filter assembly, the openings of the magnetic filter assembly being aligned with the openings in the voltage source to allow passage of charged particles from a source plasma in said source region to said processing region.

25. A plasma processing apparatus as recited in claim 23, wherein said process gas injection device includes a plurality of gas injection tubes, each gas injection tube including one or more gas outlet openings and each tube being coupled to a source of said gaseous process material, the tubes being arranged in said reaction chamber to define a plurality of openings therebetween, said openings in said process gas injection device being generally aligned with the openings in the magnetic filter assembly and with the openings in the voltage source to allow passage of charged particles from a source plasma in said source region to said processing region.

26. A plasma processing apparatus as recited in claim 25, further comprising a cover structure constructed of silicon material mounted in said reaction chamber between said plurality of gas injection tubes and said processing region.

27. A plasma processing apparatus as recited in claim 17, wherein said electrode is in electrical communication with one or more RF power sources.

28. A plasma processing apparatus as recited in claim 17, wherein said electrode is movably mounted in said reaction chamber for movement generally toward and away from the processing region.

29. A plasma processing apparatus as recited in claim 16, wherein said reaction chamber includes a vacuum pumping port for removing gaseous material from said reaction chamber.

30. A method for processing a workpiece, the method comprising:

generating a source plasma;

providing a process gas;

controlling a flow of charged particles from the source plasma into the process gas to generate a process plasma from the process gas and to control properties of the process plasma; and

striking the workpiece with charged particles from the process plasma.

31. A method for processing a workpiece as recited in claim 30, wherein said controlling the flow of charged particles includes imposing a magnetic field between the source plasma and the process gas.

32. A method for processing a workpiece as recited in claim 31, wherein said magnetic field is of constant field strength.

33. A method for processing a workpiece as recited in claim 31, wherein the imposing is accomplished utilizing one or more permanent magnets.

34. A method for processing a workpiece as recited in claim 31, wherein the field strength of said magnetic field is variable.

35. A method for processing a workpiece as recited in claim 34, wherein the imposing is accomplished utilizing a double picket fence shield.

36. A method for processing a workpiece as recited in claim 35, wherein the double picket fence shield has a DC potential.

37. A method for processing a workpiece as recited in claim 34, wherein the imposing is accomplished utilizing a single picket fence shield.

38. A method for processing a workpiece as recited in claim 37, wherein the single picket fence shield has a DC potential.

39. A method for processing a workpiece as recited in claim 31, wherein said source plasma has a relatively high electron temperature and wherein said controlling the flow of charged particles includes utilizing said magnetic field to inhibit electrons having the relatively high electron temperature from flowing into said process gas and to allow electrons having a relatively low electron temperature to flow into said process gas.

40. A method for processing a workpiece as recited in claim 31, wherein said controlling further includes controlling said magnetic field to control the EEDF of the process plasma.

41. A method for processing a workpiece as recited in claim 31, wherein said controlling further includes controlling the potential of said source plasma.

42. A method for processing a workpiece as recited in claim 41, wherein said controlling further includes controlling the EEDF of the source plasma by controlling the potential of said source plasma.

43. A method for processing a workpiece as recited in claim 41, wherein said controlling further includes controlling the potential of said source plasma to control the energy of positive ions entering said process gas.

44. A method for processing a workpiece as recited in claim 41, wherein said controlling said potential of said source plasma is accomplished by providing a source electrode, said source electrode being electrically communicated to a controllable voltage source and having at least one surface substantially in contact with the source plasma.

45. A method for processing a workpiece as recited in claim 41, wherein the generating the source plasma comprises generating a high density source plasma utilizing an ICP coil.

46. A plasma processing apparatus for processing a workpiece, the apparatus comprising:

a reaction chamber having an interior;

a module constructed and arranged to divide said interior into a source region and a processing region;

a plasma generating device mounted to said chamber and being constructed and arranged to generate a source plasma in said source region; and

a chuck electrode constructed and arranged to support a workpiece in said processing region;

said module comprising a process gas injection device constructed and arranged to inject a gaseous process material into said process region of said reaction chamber, a potential controlling electrode constructed and arranged to control the potential of the source plasma, and a magnetic filter assembly constructed and arranged to impose a magnetic field generally between said source region and said process region to control the flow of charged particles from the source plasma into the gaseous process material to generate a process plasma in said process region.

47. The plasma processing apparatus as recited in claim 46, wherein said chuck electrode is further constructed and arranged to generate a potential to attract charged particles from the process plasma toward the workpiece so that the charged particles strike the workpiece.

48. In a plasma processing device having a reaction chamber and structure for supporting a workpiece within the reaction chamber:

a unit removably mounted in the reaction chamber constructed and arranged to divide the reaction chamber interior into a source region and a processing region; and

a plasma generating device mounted to said chamber and being constructed and arranged to generate a source plasma in said source region;

said unit comprising a process gas injection device constructed and arranged to inject a gaseous process material into said process region of said reaction chamber, a potential controlling electrode constructed and arranged to control the potential of the source plasma, and a magnetic filter assembly constructed and arranged to impose a magnetic field generally between said source region and said process region to control the flow of charged particles from the source plasma into the gaseous process material to generate a process plasma in said process region.