Plasma processing apparatus adjusted for a batch-processing of a plurality of wafers with plasma gases

• US 5,639,309 A
• Filed: 03/15/1996
• Issued: 06/17/1997
• Est. Priority Date: 03/17/1995
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Akimoto, Takeshi
• Primary Examiner(s): Breneman, R. Bruce
• Assistant Examiner(s): CHANG, JONI YUK YING
• Application Number:
  US08/616,212
• Time in Patent Office: 459 Days
• Field of Search: 118/723 MW, 118/723 MP, 118/723 MA, 118/723 MR, 118/723 ME, 118/723 E, 118/723 ER, 156/345, 204/298.38
• US Class Current: 118/723.0MP
• CPC Class Codes: H01J 37/32192 Microwave generated discharge H01J37/32357, H01J37/32366, H01J37/32394, H01J37/32403 take precedence

Abstract

The present invention provides an apparatus for a batch processing of a plurality of substrates at a time with plasma gas. The above chamber comprises the following elements. A chamber is provided for a batch processing of a plurality of substrates at a time with plasma gas. A plurality of sampling stages are accommodated within the chamber. The sampling stages are spaced apart from each other. Bottom electrodes are provided on the plurality of sampling stages. The bottom electrodes are spaced apart from each other so that substrates are placed on the bottom electrodes. The same number of top electrodes, as the bottom electrodes, are provided over a space which is positioned over the substrates. The top electrodes are positioned to make pairs with the bottom electrodes so that the substrates are positioned between the top and bottom electrodes paired respectively. Each of the top electrodes is divided into a plurality of parts separated from each other by microwave radiation ports through which microwave radiates toward the substrates. A process gas introduction section is provided on the chamber at a level above the substrates and below the top electrodes for introducing a process gas to the space over the substrates. A process gas discharging section is provided on the chamber for discharging the process gas from the chamber. A microwave radiation section is provided over the top electrodes for radiating microwaves toward the substrates via the microwave radiation ports to excite process gasses introduced by the process gas introducing section and generate plasma gases. A high frequency voltage applying section is provided to be electrically connected to at least any of the top and bottom electrodes for applying high frequency voltages between the top and bottom electrodes at high frequencies to accelerate plasma gases for processing the substrates.

Claims

1. An apparatus for a batch processing of a plurality of substrates at a time with plasma gas, comprising:

a chamber;

a plurality of sampling stages accommodated within said chamber, said sampling stages being spaced apart from each other;

bottom electrodes being provided on said plurality of sampling stages, said bottom electrodes being spaced apart from each other, so that substrates are placed on said bottom electrodes;

the same number of top electrodes, as said bottom electrodes, being provided over a space which is positioned over said substrates, said top electrodes being positioned to make pairs with said bottom electrodes so that said substrates are positioned between said top and bottom electrodes paired respectively, each of said top electrodes being divided into a plurality of parts separated from each other by microwave radiation ports through which microwave radiates toward said substrates;

means being provided on said chamber at a level above said substrates and below said top electrodes for introducing a process gas to said space over said substrates;

means being provided on said chamber for discharging said process gas from said chamber;

means being provided over said top electrodes for radiating microwaves toward said substrates via said microwave radiation ports to excite process gasses introduced by said process gas introducing means and generate plasma gases; and

means being electrically connected to at least any of said top and bottom electrodes for applying high frequency voltages between said top and bottom electrodes at high frequencies to accelerate plasma gases for processing said substrates.

2. The apparatus as claimed in claim 1, wherein said chamber has a substantially rectangular parallelepiped shape.

3. The apparatus as claimed in claim 1, wherein said sampling stages are arranged in matrix at the same level.

4. The apparatus as claimed in claim 1, wherein said means for applying high frequency voltages comprises the same number of power supplies as said sampling stages, said power supplies being provided outside said chamber and being electrically connected to said bottom electrodes through walls of the chamber.

5. The apparatus as claimed in claim 1, wherein said microwave radiation ports varies in opening area over positions so that intensity of microwave radiation is uniform over positions.

6. The apparatus as claimed in claim 1, wherein said top electrodes are provided on a bottom surface of a ceramic plane plate extending in a horizontal plane.

7. The apparatus as claimed in claim 1, wherein said top electrodes are separated from each other by an insulator provided on the bottom surface of the ceramic plane plate.

8. The apparatus as claimed in claim 1, wherein said process gas discharging means is provided at a bottom portion of said chamber.

9. The apparatus as claimed in claim 8, wherein said process gas discharging means comprises:

at least a process gas discharge nozzle having one end connected to said bottom portion of said chamber;

means being provided at an intermediate portion of said process gas discharge nozzle for adjusting a pressure of said process gas within said chamber; and

means being provided at the opposite end of said process gas discharge nozzle for reducing said pressure of said process gas within said chamber.

10. The apparatus as claimed in claim 9, wherein said process gas discharge nozzle has a cylindrical shape.

11. The apparatus as claimed in claim 9,

wherein said process gas pressure adjusting means comprises a variable conductance valve;

and

wherein said process gas pressure reducing means comprises a vacuum pump.

12. The apparatus as claimed in claim 8,

wherein said process gas discharging means has the same number of process gas discharge nozzles as said sampling stages, said process gas discharge nozzles being integrated at said opposite end into a single nozzle;

and

wherein a plurality of variable conductance valves are provided for every said process gas discharge nozzles.

13. The apparatus as claimed in claim 8, wherein said process gas discharge nozzle extends from said bottom portion of said chamber in a downward direction.

14. The apparatus as claimed in claim 1, wherein said means for radiating microwaves comprises:

the same number of dielectric plates, as said top electrodes, being provided over said top electrodes, said dielectric plates are positioned to make pairs with said top electrodes so that said dielectric plates are positioned over every said substrates; and

microwave guides being coupled to said dielectric plates for transmitting microwaves through said dielectric plates separately and radiating microwaves via said microwave radiation ports toward said substrates individually.

15. The apparatus as claimed in claim 14, wherein said dielectric plates are made of Teflon.

16. The apparatus as claimed in claim 14, further comprising a ceramic plate provided to extend under said dielectric plates and over said top electrodes, where said ceramic plate has a thickness which is sufficiently smaller for allowing microwaves to penetrate said ceramic plate.

17. The apparatus as claimed in claim 14, further comprising separation plates between said dielectric plates to separate said dielectric plates from each other.

18. The apparatus as claimed in claim 1, wherein said microwave radiation ports vary in opening area over positions so that said microwaves radiate uniformly over positions.

19. The apparatus as claimed in claim 1, wherein said high frequency voltage applying means is capable of applying individual high frequency voltages independently to a plurality of pairs of said top and bottom electrodes where voltage levels and frequencies of said individual high frequency voltages are independently controlled.

20. The apparatus as claimed in claim 19, wherein said high frequency voltage applying means comprises the same number of high frequency power supplies, as said bottom electrodes, being electrically connected to said bottom electrodes respectively and said high frequency power supplies are provided outside of said chamber.

21. The apparatus as claimed in claim 1, further comprising isolation plates being provided to extend from between said sampling stages to between said top electrodes so as to isolate spaces over said substrates and under said top electrodes.

22. The apparatus as claimed in claim 1, wherein said process gas introducing means includes the same number of sets of gas introduction ports for introducing process gases into said spaces over said substrates respectively, provided gas flow rates of said sets of gas introduction ports are independently controlled.

23. The apparatus as claimed in claim 22, wherein said sets of gas introduction ports are provided in walls of said chamber.

24. The apparatus as claimed in claim 23, wherein said sets of gas introduction ports are arranged laterally at a constant pitch.

25. The apparatus as claimed in claim 22, wherein said sets of gas introduction ports are provided in said top electrodes.

26. The apparatus as claimed in claim 22, wherein said sets of gas introduction ports are provided both in said top electrodes and walls of said chamber.

27. The apparatus as claimed in claim 22, further comprising isolation plates being provided to extend from between said sampling stages to between said top electrodes so as to isolate spaces over said substrates and under said top electrodes, wherein said sets of gas introduction ports are provided both in said isolation plates and walls of said chamber.

28. The apparatus as claimed in claim 1, further comprising isolation plates being provided to extend from between said sampling stages to between said top electrodes so as to isolate spaces over said substrates and under said top electrodes, wherein said sets of gas introduction ports are provided both in said top electrodes and said isolation plates.

29. The apparatus as claimed in claim 1, further comprising isolation plates being provided to extend from between said sampling stages to between said top electrodes so as to isolate spaces over said substrates and under said top electrodes, wherein said sets of gas introduction ports are provided in said top electrodes, walls of said chamber and said isolation plates.

30. The apparatus as claimed in claim 1, further comprising magnets provided around said chamber for applying a time-constant magnetic field to said space within said chamber to reduce variations in density of said plasma gas.

31. The apparatus as claimed in claim 1, further comprising the same number of heaters as said sampling stages for heating said substrates independently so that temperatures of said substrates are controlled independently.

32. The apparatus as claimed in claim 1, further comprising a lateral meshed plate being provided between said sampling plates and said chamber for confining said plasma gases within said spaces over said substrates, wherein said lateral meshed plate has pores which prevent said plasma gases from passing through said pores.

33. An apparatus for a batch processing of a plurality of substrates at a time with plasma gas, comprising:

a chamber;

a plurality of sampling stages accommodated within said chamber, said sampling stages being spaced apart from each other;

bottom electrodes being provided on said plurality of sampling stages, said bottom electrodes being spaced apart from each other, so that substrates are placed on said bottom electrodes;

the same number of top electrodes, as said bottom electrodes, being provided over a space which is positioned over said substrates, said top electrodes being positioned to make pairs with said bottom electrodes so that said substrates are positioned between said top and bottom electrodes paired respectively, each of said top electrodes being divided into a plurality of parts separated from each other by microwave radiation ports through which microwave radiates toward said substrates, said microwave radiation ports varying in opening area over positions so that intensity of microwave radiation is uniform over positions;

the same number of sets of gas introduction ports being provided on said chamber at a level above said substrates and below said top electrodes for introducing process gases into said spaces over said substrates respectively, provided gas flow rates of said sets of gas introduction ports are independently controlled;

at least a process gas discharge nozzle being provided at a bottom portion of said chamber and having one end connected to said bottom portion of said chamber;

means being provided at an intermediate portion of said process gas discharge nozzle for adjusting a pressure of said process gas within said chamber;

means being provided at the opposite end of said process gas discharge nozzle for reducing said pressure of said process gas within said chamber;

the same number of dielectric plates, as said top electrodes, being provided over said top electrodes, said dielectric plates are positioned to make pairs with said top electrodes so that said dielectric plates are positioned over every said substrates;

microwave guides being coupled to said dielectric plates for transmitting microwaves through said dielectric plates separately and radiating microwaves via said microwave radiation ports toward said substrates individually to excite process gasses introduced and generate plasma gases; and

means being electrically connected to at least any of said top and bottom electrodes for applying individual high frequency voltages independently to a plurality of pairs of said top and bottom electrodes where voltage levels and frequencies of said individual high frequency voltages are independently controlled.

34. The apparatus as claimed in claim 33, wherein said chamber has a substantially rectangular parallelepiped shape.

35. The apparatus as claimed in claim 33, wherein said sampling stages are arranged in matrix at the same level.

36. The apparatus as claimed in claim 33, wherein said means for applying high frequency voltages comprises the same number of power supplies as said sampling stages, said power supplies being provided outside said chamber and being electrically connected to said bottom electrodes through walls of the chamber.

37. The apparatus as claimed in claim 33, wherein said top electrodes are provided on a bottom surface of a ceramic plane plate extending in a horizontal plane.

38. The apparatus as claimed in claim 33, wherein said top electrodes are separated from each other by an insulator provided on the bottom surface of the ceramic plane plate.

39. The apparatus as claimed in claim 33, wherein said process gas discharge nozzle has a cylindrical shape.

40. The apparatus as claimed in claim 33,

wherein said process gas pressure adjusting means comprises a variable conductance valve;

and

wherein said process gas pressure reducing means comprises a vacuum pump.

41. The apparatus as claimed in claim 33, wherein said process gas discharging means has the same number of process gas discharge nozzles as said sampling stages, said process gas discharge nozzles being integrated at said opposite end into a single nozzle;

and

wherein a plurality of variable conductance valves are provided for every said process gas discharge nozzles.

42. The apparatus as claimed in claim 33, wherein said dielectric plates are made of Teflon.

43. The apparatus as claimed in claim 33, further comprising a ceramic plate provided to extend under said dielectric plates and over said top electrodes, where said ceramic plate has a thickness which is sufficiently smaller for allowing microwaves to penetrate said ceramic plate.

44. The apparatus as claimed in claim 33, further comprising separation plates between said dielectric plates to separate said dielectric plates from each other.

45. The apparatus as claimed in claim 33, wherein said high frequency voltage applying means comprises the same number of high frequency power supplies, as said bottom electrodes, being electrically connected to said bottom electrodes respectively and said high frequency power supplies are provided outside of said chamber.

46. The apparatus as claimed in claim 33, further comprising isolation plates being provided to extend from between said sampling stages to between said top electrodes so as to isolate spaces over said substrates and under said top electrodes.

47. The apparatus as claimed in claim 33, wherein said sets of gas introduction ports are provided in walls of said chamber.

48. The apparatus as claimed in claim 46, wherein said sets of gas introduction ports are provided both in walls of said chamber and in said isolation plates.

49. The apparatus as claimed in claim 33, wherein said sets of gas introduction ports are provided in said top electrodes.

50. The apparatus as claimed in claim 33, wherein said sets of gas introduction ports are provided both in said top electrodes and walls of said chamber.

51. The apparatus as claimed in claim 46, wherein said sets of gas introduction ports are provided both in said top electrodes and said isolation plates.

52. The apparatus as claimed in claim 46, wherein said sets of gas introduction ports are provided in said top electrodes, walls of said chamber and said isolation plates.

53. The apparatus as claimed in claim 33, further comprising magnets provided around said chamber for applying a time-constant magnetic field to said space within said chamber to reduce variations in density of said plasma gas.

54. The apparatus as claimed in claim 33, further comprising the same number of haters as said sampling stages for hating said substrates independently so that temperatures of said substrates are controlled independently.

55. The apparatus as claimed in claim 33, further comprising a lateral meshed plate being provided between said sampling plates and said chamber for confining said plasma gases within said spaces over said substrates, wherein said lateral meshed plate has pores which prevent said plasma gases from passing through said pores.