Shaping a plasma with a magnetic field to control etch rate uniformity

• US 6,673,199 B1
• Filed: 03/07/2001
• Issued: 01/06/2004
• Est. Priority Date: 03/07/2001
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Singh, Saravjeet, Yamartino, John M., Loewenhardt, Peter K., Lubomirsky, Dmitry
• Primary Examiner(s): HASSANZADEH, PARVIZ
• Application Number:
  US09/800,876
• Time in Patent Office: 1,035 Days
• Field of Search: 156/345.49, 156/345.46, 204/298.37, 118/723.MA, 118/723.MR, 118/723.I, 118/723.E, 118/723.MN, 216/68, 438/732, 438/729, 438/728
• US Class Current: 156/345.49
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/32623 Mechanical discharge control means
• CPC Class Codes: H01J 37/3266 Magnetic control means

Abstract

A substrate etching chamber has a substrate support, a gas supply to introduce a process gas into the chamber; an inductor antenna to sustain a plasma of the process gas in a process zone of the chamber, and an exhaust to exhaust the process gas. A magnetic field generator disposed about the chamber has first and second solenoids. A controller is adapted to control a power supply to provide a first current to the first solenoid and a second current to the second solenoid, thereby generating a magnetic field in the process zone of the chamber to controllably shape the plasma in the process zone to reduce etch rate variations across the substrate.

Claims

1. A substrate etching chamber comprising:

a substrate support to support a substrate in a process zone;

a gas supply to introduce a process gas into the process zone;

an inductor antenna to inductively couple energy to the process gas to form a plasma of the process gas in the process zone;

a magnetic field generator to generate a magnetic field in the process zone, the magnetic field generator comprising first and second solenoids above a ceiling of the chamber, the second solenoid being radially offset from the first solenoid, and a power supply to power the solenoids;

a controller adapted to control the power supply of the magnetic field generator to pass a first current through the first solenoid and pass a second current through the second solenoid, the second current being in the opposite direction of the first current; and

an exhaust to exhaust the process gas.

2. A chamber according to claim 1 wherein the controller is adapted to control the power supply to generate a magnetic field in the process zone to shape the plasma to reduce etch rate variations across the substrate.

3. A chamber according to claim 2 wherein the controller is adapted to control the power supply to generate a magnetic field in the process zone to shape the plasma to provide a substrate etch rate uniformity that is less than about 7%.

4. A chamber according to claim 1 wherein the ratio of the first current to the second current is less than about 2:

1.

5. A chamber according to claim 4 wherein the ratio is at least about 1:

1.

6. A chamber according to claim 1 wherein the first and second solenoids are substantially coplanar.

7. A chamber according to claim 1 wherein the first and second solenoids are vertically or horizontally offset from one another.

8. A chamber according to claim 1 wherein the first and second solenoids are positioned radially outward from the inductor antenna.

9. A chamber according to claim 1 comprising a magnetic shield about the first and second solenoids.

10. A chamber according to claim 1 wherein the first and second solenoids are coplanar.

11. A chamber according to claim 1 wherein the first and second solenoids are not coplanar.

12. A substrate etching method comprising:

(a) placing a substrate in a chamber defining a process zone;

(b) introducing a process gas into the process zone;

(c) inductively coupling energy to the process gas to form a plasma in the process zone;

(d) generating a magnetic field in the process zone by providing a first current to a first solenoid above a ceiling of the chamber and a second current to a second solenoid above the ceiling of the chamber that is radially offset from the first solenoid, the first current being in the opposite direction to the second current; and

(e) exhausting the process gas from the process zone.

13. A method according to claim 12 comprising generating a magnetic field to shape the plasma to reduce etch rate variations across the substrate.

14. A method according to claim 13 comprising generating a magnetic field to shape the plasma to provide a substrate etch rate uniformity that is less than about 7%.

15. A method according to claim 12 wherein the ratio of the first current to the second current is less than about 2:

1.

16. A method according to claim 15 wherein the ratio is at least about 1:

1.

17. A method according to claim 12 wherein (d) comprises generating a magnetic field in the process zone by providing the first current to the first solenoid and the second current to the second solenoid, the first and second solenoids being coplanar.

18. A method according to claim 12 wherein (d) comprises generating a magnetic field in the process zone by providing the first current to the first solenoid and the second current to the second solenoid, the first and second solenoids being non-coplanar.

19. A substrate etching chamber comprising:

a substrate support to support a substrate in a process zone;

a gas supply to introduce a process gas into the process zone;

a gas energizer comprising a process electrode to couple energy to the process gas to form a plasma of the process gas in the process zone and an RF power supply to provide an RF voltage to the process electrode;

a magnetic field generator to generate a controllable magnetic field in the process zone, the magnetic field generator comprising first and second solenoids disposed above a ceiling of the chamber and a DC power supply to pass direct current through the first and second solenoids in opposite directions; and

an exhaust to exhaust the process gas.

20. A chamber according to claim 19 comprising a controller adapted to control the DC power supply to provide current to the first and second solenoids to generate a magnetic field in the process zone that shapes the plasma in the process zone to reduce etch rate variations across the substrate.

21. A chamber according to claim 19 wherein the controller is adapted to control the DC power supply to provide a first current to the first solenoid and a second current to the second solenoid.

22. A chamber according to claim 21 wherein the first and second currents are in opposite directions.

23. A chamber according to claim 21 wherein the ratio of the first current to the second current is less than about 2:

1.

24. A chamber according to claim 23 wherein the ratio is at least about 1:

1.

25. A chamber according to claim 19 wherein the first and second solenoids are substantially coplanar.

26. A chamber according to claim 19 wherein the first and second solenoids are positioned radially outward from the inductor coil.

27. A chamber according to claim 19 comprising a magnetic shield about the first and second solenoids.

28. A chamber according to claim 19 wherein the first and second solenoids are coplanar.

29. A chamber according to claim 19 wherein the first and second solenoids are not coplanar.

30. A chamber according to claim 19 wherein the controller is adapted to control the DC power supply to generate a magnetic field to shape the plasma in the process zone to provide a substrate etch rate uniformity that is less than about 7%.

31. A substrate etching method comprising:

(a) placing a substrate in a chamber defining a process zone;

(b) introducing a process gas into the process zone;

(c) coupling energy to the process gas to form a plasma in the process zone by providing an RF current voltage to a process electrode;

(d) generating a magnetic field in the process zone by providing a first direct current to a first solenoid above a ceiling of the chamber and a second direct current to a second solenoid above the ceiling of the chamber that is radially offset from the first solenoid, the first and second direct currents being in opposite directions; and

(e) exhausting the process gas from the process zone.

32. A method according to claim 31 comprising generating a magnetic field to shape the plasma to reduce etch rate variations across the substrate.

33. A method according to claim 32 comprising generating a magnetic field to shape the plasma to provide a substrate etch rate uniformity that is less than about 7%.

34. A method according to claim 31 comprising generating the magnetic field by passing a first current through the first solenoid and a second current through the second solenoid.

35. A method according to claim 34 wherein the ratio of the first current to the second current is less than about 2:

1.

36. A method according to claim 35 wherein the ratio is at least about 1:

1.

37. A method according to claim 31 wherein (d) comprises generating a magnetic field in the process zone by providing the first direct current to the first solenoid and the second direct current to the second solenoid, the first and second solenoids being coplanar.

38. A method according to claim 31 wherein (d) comprises generating a magnetic field in the process zone by providing the first direct current to the first solenoid and the second direct current to the second solenoid, the first and second solenoids being non-coplanar.

39. A substrate etching chamber comprising:

a substrate support to support a substrate in a process zone;

a gas supply to introduce a process gas into the process zone;

a gas energizer comprising a process electrode to couple energy to the process gas to form a plasma of the process gas in the process zone and an RF power supply to provide an RF voltage to the process electrode;

a magnetic field generator to generate a controllable magnetic field in the process zone, the magnetic field generator comprising first and second solenoids that are non-coplanar and disposed above a ceiling of the chamber, and a DC power supply to pass direct current through the first and second solenoids in opposite directions; and

an exhaust to exhaust the process gas.