Wafer processing apparatus and method

• US 4,842,686 A
• Filed: 07/17/1987
• Issued: 06/27/1989
• Est. Priority Date: 07/17/1987
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Loewenstein, Lee M., Davis, Cecil J., Matthews, Robert T., Jucha, Rhett B., Jones, John I.
• Primary Examiner(s): Powell, William A.
• Application Number:
  US07/075,016
• Time in Patent Office: 711 Days
• Field of Search: 156/643, 156/646, 156/653, 156/656, 156/657, 156/659.1, 156/662, 156/345, 252/79.1, 118/728, 118/729, 118/50.1, 118/620, 427/38, 427/39, 427/41, 427/54.1, 204/192.1, 204/192.12, 204/192.23, 204/192.25, 204/192.32, 204/192.35, 204/192.36, 204/192.37, 204/298, 134/1, 414/217, 414/222, 414/225, 414/226, 414/411, 414/416, 414/422, 414/744 R, 414/744 A, 414/744 B, 414/744 C, 437/228, 437/234, 437/235, 437/238, 437/241, 437/245
• US Class Current: 438/709
• CPC Class Codes: C23C 16/482 using incoherent light, UV to IR, e.g. lamps
• CPC Class Codes: C23C 16/517 using a combination of discharges covered by two or more of groups C23C16/503 - C23C16/515
• CPC Class Codes: C23C 16/54 Apparatus specially adapted for continuous coating
• CPC Class Codes: G03F 7/70808 Construction details, e.g. housing, load-lock, seals or windows for passing light in or out of apparatus
• CPC Class Codes: G03F 7/70866 of mask or workpiece

Abstract

A plasma reactor with in situ ultraviolet generation processing aparatus and method. Ultraviolet light to illuminate the face of a wafer being processed is generated by a plasma which is within the vacuum processing chamber but is remote from the face of the wafer. It is useful to design the gas flow system so that the ultraviolet-generating plasma has its own gas feed, and the reaction products from the ultraviolet-generating plasma do not substantially flow or diffuse to the wafer face. A transparent isolator between the ultraviolet plasma space and the processing space near the wafer face is useful so that the ultraviolet plasma can be operated at a vacuum level slightly different from that used near the wafer face, but this transparent window is not made thick enough to act as a full vacuum seal. Optionally, this window may be omitted entirely.

Claims

1. An apparatus for vacuum processing of wafers, comprising:

(a) a vacuum processing chamber;

(b) a wafer support within said vacuum processing chamber, said wafer support being capable of supporting a wafer;

(c) gas flow passages positioned to permit release of a desired process gas flow in proximity to the surface of the wafer; and

(d) an ultraviolet energy source within said vacuum processing chamber separate from the wafer and positioned to illuminate the wafer with ultraviolet energy.

3. The apparatus of claim 1, wherein said load lock is connected to an adjacent vacuum processing chamber by a vacuum port, and wherein said vacuum port is also controlled by said control system, and wherein said control system is programmed to prevent opening of said vacuum port until said output signal has indicated that substantially no particulate has been present in the space within the interior of said processing chamber for at least a predetermined period of time.

4. The apparatus of claim 1, further comprising an environmental and vacuum control device for maintaining a vacuum in said processing chamber and for removal of any particulate.

5. The apparatus of claim 1, wherein the wafer is supported in a manner such that a side on which circuit components are to be formed faces downward.

6. The apparatus of claim 1 further comprising a source of radiant energy radiatively coupled to said wafer.

7. The apparatus of claim 6, wherein said source of radiant energy provides maximum specific power at wavelengths in the visible range.

8. The apparatus of claim 6, wherein said radiant energy source comprises a plurality of incandescent lamps.

9. The apparatus of claim 6 wherein the radiant heat source reflectors are cooled by contact with a water cooled housing.

10. The apparatus of claim 6, further comprising a transparent vacuum wall separating said source of radiant energy from the wafer.

11. The apparatus of claim 10, wherein said vacuum wall is sealed to said chamber by a radially elastically expandable metallic seal which includes a deformable soft portion.

12. The apparatus of claim 5 further comprising at least one reflector.

13. The apparatus of claim 12 wherein said at least one reflector is coated with gold.

14. The apparatus of claim 1, further comprising:

(a) a gas supply;

(b) a microwave power source;

(c) a microwave cavity in which power supplied by the microwave power source excites the gas from the gas supply.

15. The apparatus of claim 1, wherein said internal ultraviolet source comprises:

(a) a ultraviolet chamber bounded on one side by the process chamber;

(b) a gas supply to the ultraviolet chamber;

(c) a thin window substantially transparent to ultraviolet light separating the process chamber from the ultraviolet chamber;

(d) an electrode for coupling radio frequency energy to a plasma inside said ultraviolet chamber.

16. The apparatus of claim 15, wherein said thin window of said ultraviolet source comprises quartz.

17. The apparatus of claim 15, wherein said thin window of said ultraviolet source comprises sapphire.

2. A method for processing of wafer, comprising the steps of:

(a) transferring a wafer into a vacuum processing chamber;

(b) flowing a desired mixture of process gases through the space in proximity to the surface of the wafer; and

(c) illuminating the surface of said wafer with ultraviolet light generated by plasma which is within said chamber but which is generated remotely from the surface of said wafer.

18. An apparatus for processing a workpiece comprising:

(a) a vacuum processing chamber within a process module;

(b) a support capable of engaging said workpiece with said chamber;

(c) gas distributors positioned within said chamber to direct a process gas to a face of said workpiece; and

(d) an ultraviolet energy source within said module away from the face of said workpiece positioned to couple ultraviolet energy to the space adjacent the face.

19. The apparatus as set forth in claim 18 including a plate between said ultraviolet energy source and said workpiece.

20. The apparatus as set forth in claim 18 wherein said plate has a different pressure on one side than another side.

21. A method of processing a workpiece comprising the steps of:

(a) disposing said workpiece into a process chamber of a process module at low pressure;

(b) introducing process gas into said chamber to a face of said workpiece; and

(c) generating ultraviolet energy within said module remote from the face of said workpiece and coupled to the space within said chamber adjacent the face.

22. A vacuum process module for processing a workpiece comprising:

(a) a heater coupled to said workpiece; and

(b) a source of ultraviolet light coupled to said workpiece.

23. A module as set forth in claim 22 wherein said workpiece has its face to be processed facing downward.

24. The module as set forth in claim 22 wherein said ultraviolet source and said heater are separately controlled to operate singly.

25. The module as set forth in claim 22 wherein said ultraviolet source and said heater are separately controlled to operate in any combination.

26. The module as set forth in claim 22 wherein said heater is a radiant heater.

27. The module as set forth in claim 26 wherein said radiant heater is located above said workpiece during processing.

28. The module as set forth in claim 26 wherein said heater is a conductive heater.

29. The module as set forth in claim 22 wherein said ultraviolet source is located below said workpiece during processing.

30. The module as set forth in claim 22 wherein said ultraviolet source is separated from and in fluid communication with the process chamber.

31. The module as set forth in claim 22 wherein the workpiece is a wafer.

32. An apparatus for vacuum processing of wafers, comprising:

(a) a first chamber;

(b) a second chamber within said first chamber with a wafer disposed therein;

(c) gas flow passages positioned to provide a gas to the wafer; and

(d) an ultraviolet energy source within a third chamber which is within said first chamber to illuminate the wafer with ultraviolet energy.

33. The apparatus of claim 32, further, comprising an environmental and vacuum control device for maintaining a vacuum in said processing chamber and for removal of any particulate.

34. The apparatus of claim 32, wherein the wafer is supported in a manner such that a side on which circuit components are to be formed faces downward.

35. The apparatus of claim 32 further comprising a source of radiant energy radiatively coupled to said wafer.

36. The apparatus of claim 35 wherein said source of radiant energy provides maximum specific power at wavelengths in the visible range.

37. The apparatus of claim 35, wherein said radiant energy source comprises a plurality of incandescent lamps.

38. The apparatus of claim 35 wherein the radiant heat source reflectors are cooled by contact with a water cooled housing.

39. The apparatus of claim 35, further comprising a transparent vacuum wall separating said source of radiant energy from the wafer.

40. The apparatus of claim 39, wherein said vacuum wall is sealed to said chamber by a radially elastically expandable metallic seal which includes a deformable soft portion.

41. The apparatus of claim 35 further comprising at least one reflector.

42. The apparatus of claim 41 wherein said at least one reflector is coated with gold.

43. The apparatus of claim 32, further comprising:

(a) a gas supply;

(b) a microwave power source;

(c) a microwave cavity in which power supplied by the microwave power source excites the gas from the gas supply.

44. The apparatus of claim 32 further including a gas supply to said third chamber.

45. The apparatus of claim 32 further including a thin window substantially transparent to ultraviolet light separating the process chamber from said third chamber.

46. The apparatus of claim 32 further including an electrode for coupling radio frequency energy to a plasma inside said third chamber.

47. The apparatus of claim 45, wherein said thin window of said ultraviolet source comprises quartz.

48. The apparatus of claim 45, wherein said thin window of said ultraviolet source comprises sapphire.

49. An apparatus for processing a workpiece comprising:

(a) a vacuum processing chamber within a process module;

(b) a support capable of engaging said workpiece with said chamber;

(c) gas distributors positioned within said chamber to direct a process gas to a face of said workiece; and

(d) an ultraviolet energy source within said module away from the face of said workpiece positioned to couple ultraviolet energy to the space adjacent the face.

50. The apparatus as set forth in claim 49 including a plate between said ultraviolet energy source and said workpiece.

51. The apparatus as set forth in claim 49 wherein said plate has a different pressure on one side than another side.

52. The apparatus of claim 49, wherein the wafer is supported in a manner such that a side on which circuit components are to be formed faces downward.

53. The method for processing of wafers, comprising the steps of:

(a) transferring a wafer into a processing chamber;

(b) introducing process gases into a first chamber within said processing chamber;

(c) illuminating the surface of said wafer with ultraviolet light generated by a plasma which is generated in a second chamber separate from said first chamber and within and in fluid communication with said processing chamber.

54. The method of claim 53, wherein the wafer is supported in a manner such that a side on which circuit components are to be formed faces downward.

55. A method of processing a workpiece comprising the steps of:

(a) disposing said workpiece into a process chamber of a process module at low pressure;

(b) introducing process gas into said chamber to a face of said workpiece; and

(c) generating ultraviolet energy within said module remote from the face of said workpiece and coupled to the space within said chamber adjacent the face.

63. The method of claim 55, wherein the wafer is supported in a manner such that a side on which circuit components are to be formed faces downward.

56. A vacuum processing module comprising:

(a) a process chamber with a wafer disposed therein;

(b) a first chamber within and in fluid communication with said process chamber;

(c) a heater coupled to said first chamber;

(d) a second chamber within and in fluid communication with said process chamber, separate from said first chamber; and

(e) a source of ultraviolet energy within said second chamber, said energy source being positioned to illuminate said wafer.

57. The module as set forth in claim 56 wherein said ultraviolet source and said heater are separately controlled to operate singly.

58. The module as set forth in claim 56 wherein said ultraviolet source and said heater are separately controlled to operate in any combination.

59. The module as set forth in claim 56 wherein said heater is a radiant heater.

60. The module as set forth in claim 56 wherein said radiant heater is located above said workpiece during processing.

61. The module as set forth in claim 56 wherein said heater is a conductive heater.

62. The module as set forth in claim 56 wherein said ultraviolet source is located below said wafer during processing.