Apparatus and method for forming thin film using upstream and downstream exhaust mechanisms

• US 20050208217A1
• Filed: 10/07/2004
• Published: 09/22/2005
• Est. Priority Date: 10/09/2003
• Status: Active Grant

• Current Assignee: ASM Japan K.K. (ASM International NV)
• Original Assignee: ASM Japan K.K. (ASM International NV)
• Inventors: Shimizu, Akira, Shinriki, Hiroshi, Kawano, Baiei
• Granted Patent: US 7,408,225 B2
• Time in Patent Office: Days
• US Class Current: 427/248.100
• CPC Class Codes: C23C 16/34 Nitrides C23C16/303 takes precedence
• CPC Class Codes: C23C 16/4412 Details relating to the exhausts, e.g. pumps, filters, scrubbers, particle traps
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: C23C 16/45544 characterized by the apparatus
• CPC Class Codes: C23C 16/45565 Shower nozzles
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32449 Gas control, e.g. control of the gas flow
• CPC Class Codes: H01J 37/32834 Exhausting

Abstract

A thin-film formation apparatus possesses a reaction chamber to be evacuated, a placing portion on which a substrate is placed inside the reaction chamber, a gas-dispersion guide installed over the placing portion for supplying a gas onto a substrate surface, a gas-supply port for introducing the gas into the gas-dispersion guide, a gas-dispersion plate disposed on the side of the substrate of the gas-dispersion guide and having multiple gas-discharge pores, a first exhaust port for exhausting, downstream of the gas-dispersion plate, the gas supplied onto the substrate surface from the gas-dispersion plate, and a second exhaust port for exhausting, upstream of the gas-dispersion plate, a gas inside the gas-dispersion guide via a space between the gas-dispersion guide and the gas-dispersion plate.

Claims

1. A thin-film formation apparatus comprising:

a reaction chamber to be evacuated;

a placing portion for placing a substrate thereon inside said reaction chamber;

a gas-dispersion guide disposed above said placing portion for supplying a gas onto a surface of said substrate;

a gas-supply port for introducing a gas into said gas-dispersion guide;

a gas-dispersion plate disposed on a substrate side of said gas-dispersion guide and having multiple gas-discharge ports;

a first exhaust port for exhausting, downstream of said gas-dispersion plate, the gas supplied onto the substrate surface; and

a second exhaust port for exhausting, upstream of said gas-dispersion plate, a gas inside said gas-dispersion guide through a gap between said gas-dispersion guide and said gas-dispersion plate.

2. The thin-film formation apparatus according to claim 1, wherein a first gas flow path is formed by communicatively connecting an internal space of said gas-dispersion guide, a space between said gas-dispersion guide and said gas-dispersion plate, and a space between said gas-dispersion plate and a substrate with the first exhaust port;

a second gas flow path is formed by communicatively connecting the internal space of said gas-dispersion guide, the space between said gas-dispersion guide and said gas-dispersion plate, and a space facing an outer circumferential wall of said gas-dispersion guide with the second exhaust port.

3. The thin-film formation apparatus according to claim 2, wherein in said second gas flow path, the space between said gas-dispersion guide and said gas-dispersion plate and the space facing the outer circumferential wall of said gas-dispersion guide are communicated with each other via an exhaust pore or an annular exhaust slit provided between an outer circumferential rim of said gas-dispersion guide and an outer circumferential portion of said gas-dispersion plate.

4. The thin-film formation apparatus according to claim 1, wherein said gas-dispersion guide has a truncated cone shape extending downward and being open at its lower side.

5. The thin-film formation apparatus according to claim 1, wherein said gas-dispersion guide further comprises an intermediate dispersion element having pores or slits for discharging a gas toward said gas-dispersion plate in the vicinity of said gas-supply port.

6. The thin-film formation apparatus according to claim 1, wherein a valve connected to an external exhaust system is connected to said second exhaust port.

7. The thin-film formation apparatus according to claim 6, wherein said valve is a valve having exhaust conductance which is variable at high speed of 100 msec or less.

8. The thin-film formation apparatus according to claim 7, wherein said valve'"'"'s minimum conductance is controlled at 1% or less of said valve'"'"'s maximum conductance.

9. The thin-film formation apparatus according to claim 7, which is configured to exhaust the gas predominantly from said second gas flow path when said valve'"'"'s conductance is maximum;

and exhaust the gas predominantly from said first gas flow path when said valve'"'"'s conductance is minimum.

10. The thin-film formation apparatus according to claim 1, wherein an electrode for applying RF power is further provided in said gas-dispersion plate.

11. The thin-film formation apparatus according to claim 1, wherein an electrode for applying RF power is further provided on a wall constituting said gas-dispersion guide.

12. The thin-film formation apparatus according to claim 1, wherein a heating source for heating a gas passing through said gas-dispersion plate is further installed in said gas-dispersion plate.

13. The thin-film formation apparatus according to claim 1, wherein a heating source for heating a gas inside said gas-dispersion guide is further installed in a wall constituting said gas-dispersion guide.

14. The thin-film formation apparatus according to claim 13, wherein a temperature of said wall is controlled within the range of 50°

C.-450°

C., and a temperature of said gas-dispersion plate is controlled at 250°

C. or below.

15. The thin-film formation apparatus according to claim 1, wherein said gas-dispersion guide further comprises an intermediate plate between said gas-dispersion plate and said gas-supply port, wherein said intermediate plate has intermediate gas-discharge pores in positions not overlapping with said gas-discharge pores of said gas-dispersion plate and functions as a second dispersion plate.

16. The thin-film formation apparatus according to claim 6, wherein said valve is configured to have conductance controlled to be approx. 10 times to approx. 1,000 times conductance of said dispersion plate when said valve is opened at maximum;

and have conductance of said valve controlled to be approx. 0.001 times to approx. 0.1 times conductance of said dispersion plate when conductance of said valve is at minimum.

17. The thin-film formation apparatus according to claim 6, wherein exhaust conductance of said exhaust valve is 30 liter/sec when said exhaust valve is opened at maximum.

18. The thin-film formation apparatus according to claim 2, wherein a purge-gas ring is disposed concentrically with said placing stand at a given distance apart from a side portion of said placing stand;

a slit is constituted by the side portion of said placing stand and said purge-gas ring; and

a third gas flow path is formed by communicatively connecting a lower space below said placing stand with the first exhaust port via said slit.

19. The thin-film formation apparatus according to claim 18, wherein said purge-gas slit has a thickness of approx. 0.5 mm to approx. 1.5 mm and a length of approx. 15 mm to approx. 40 mm in said placing stand'"'"'s axial direction.

20. The thin-film formation apparatus according to claim 18, wherein an annular slit is disposed, as an entrance of the first exhaust port, concentrically outside said placing stand and substantially and nearly at the same level as that of a substrate-placing surface of the placing stand.

21. The thin-film formation apparatus according to claim 18, wherein said purge-gas ring is provided around the side portion of said placing stand at a lower position than the substrate-placing surface;

and an exhaust ring is disposed above said purge-gas ring along and concentrically with the side portion of said placing stand, thereby constituting an exhaust slit which is an annular slit disposed as an entrance of said exhaust port between said exhaust ring and said purge-gas ring.

22. The thin-film formation apparatus according to claim 21, wherein said exhaust slit has a thickness larger than a thickness of said purge-gas slit.

23. The thin-film formation apparatus according to claim 22, wherein said exhaust slit has a thickness of approx. 2 mm to approx. 4 mm.

44. The method according to claim 16, wherein RF power is applied between said gas-dispersion plate and said placing portion when the gas is supplied onto the substrate.

45. The method according to claim 16, wherein RF power is applied between said gas-dispersion guide and said placing portion when the gas is supplied onto the substrate.

46. The method according to claim 16, wherein a gas going through said gas-dispersion plate is heated by a heating source provided in said gas-dispersion plate.

47. The method according to claim 16, wherein a gas inside said gas-dispersion guide is heated by a heating source provided on a wall comprising said gas-dispersion guide.

48. The method according to claim 47, wherein said wall is controlled at a temperature within the range of 50°

C.-450°

C., and said gas-dispersion plate is controlled at a temperature of 200°

C. or below.

49. The method according to claim 16, wherein said gas-dispersion guide further comprises an intermediate plate between said gas-dispersion plate and said gas-supply port, and said intermediate plate has intermediate discharge pores in positions not overlapping with said gas-discharge pores in said gas-dispersion plate wherein the gas is dispersed upstream of said gas-dispersion plate by going through said intermediate discharge pores.

24. A method for forming a thin film comprising the steps of:

placing a substrate on a placing portion inside a reaction chamber evacuated;

introducing a gas from a gas-supply port to a gas-dispersion guide installed above said placing portion;

supplying the gas onto a substrate surface via a gas-dispersion plate disposed on a substrate side of the gas-dispersion guide and having multiple gas-discharge pores;

exhausting the gas supplied from said gas-dispersion plate onto the substrate surface from a first exhaust port downstream of said gas-dispersion plate; and

when switching to a subsequent gas to be introduced from said gas-supply port to said gas-dispersion guide, exhausting the gas remaining inside said gas-dispersion guide via a space between said gas-dispersion guide and said gas-dispersion plate from a second exhaust port upstream of said gas-dispersion plate.

25. The method according to claim 24, wherein said gas-dispersion guide has a truncated cone shape extending downward and being open at its lower side and further comprises an intermediate dispersion element having pores or slits for discharging gas toward said gas-dispersion plate in the vicinity of said gas-supply port, wherein the gas is supplied to said gas-dispersion plate via said intermediate dispersion element.

26. The method according to claim 24, wherein a first gas flow path is formed by communicatively connecting an internal space of said gas-dispersion guide, a space between said gas-dispersion guide and said gas-dispersion plate, and a space between said gas-dispersion plate and a substrate with the first exhaust port;

a second gas flow path is formed by communicatively connecting the internal space of said gas-dispersion guide, the space between said gas-dispersion guide and said gas-dispersion plate, and a space facing an outer circumferential wall of said gas-dispersion guide with the second exhaust port, wherein exhaust gas volumes from said first exhaust port and said second exhaust port are controlled by changing exhaust conductance of said second gas flow path against exhaust conductance of said first gas flow path.

27. The method according to claim 26, wherein in said second gas flow path, the space between said gas-dispersion guide and said gas-dispersion plate and the space facing the outer circumferential wall of said gas-dispersion guide are communicated with each other via an exhaust pore or an annular exhaust slit provided between an outer circumferential rim of said gas-dispersion guide and an outer circumferential portion of said gas-dispersion plate, wherein the second gas flow path is exhausted via the exhaust pore or said annular exhaust slit.

28. The method according to claim 24, wherein a gas after the gas switching is introduced into said gas-dispersion guide from said gas-supply port substantially simultaneously with start of exhausting gas from the second exhaust port.

29. The method according to claim 24, wherein a gas after the gas switching is introduced into said gas-dispersion guide from said gas-supply port after exhausting gas from the second exhaust port is nearly completed.

30. The method according to claim 26, wherein changes of conductance of the second gas flow path are synchronized with the gas switching.

31. The method according to claim 26, wherein the gas is exhausted predominantly from the second gas flow path by controlling conductance of said second gas flow path to be approx. 10 times to approx. 1,000 times conductance of said first gas flow path;

and the gas is exhausted predominantly from the first exhaust port by controlling conductance of said second gas flow path to be approx. 0.001 times to approx. 0.1 times conductance of said first gas flow path.

32. The method according to claim 26, wherein the gas switching is executed by varying exhaust conductance at high speed of approx. 100 msec or below.

33. The method according to claim 26, wherein exhaust from the second exhaust port is controlled by controlling minimum conductance of said second gas flow path at 1% or below of its maximum conductance.

34. The method according to claim 26, wherein a purge-gas ring is disposed concentrically with said placing stand at a given distance apart from aside portion of said placing stand;

a slit is constituted by the side portion of said placing stand and said purge-gas ring; and

a third gas flow path is formed by communicatively connecting a lower space below said placing stand with the first exhaust port via said slit, wherein a purge gas is introduced from the third gas flow path when the first gas flow path is being used, thereby suppressing diffusion of a gas from the first gas flow path to the lower space below said placing stand.

35. The method according to claim 34, wherein the purge-gas slit has a thickness of approx. 0.5 mm to approx. 1.5 mm and a length of approx. 15 mm to approx. 40 mm in said placing stand'"'"'s axial direction.

36. The method according to claim 34, wherein an annular slit is disposed, as an entrance of said first exhaust port, concentrically outside said placing stand and substantially and nearly at the same level as that of a substrate-placing surface of said placing stand.

37. The method according to claim 34, wherein said purge-gas ring is provided around the side portion of said placing stand at a lower position than the substrate-placing surface;

and an exhaust ring is disposed above the purge-gas ring along and concentrically with the side portion of said placing stand, thereby constituting a exhaust slit which is an annular slit disposed between said exhaust ring and said purge-gas ring as an entrance of the exhaust port.

38. The method according to claim 37, wherein the gas is exhausted by setting a thickness of said exhaust slit larger than a thickness of said purge-gas slit.

39. The method according to claim 38, wherein the gas is exhausted by setting a thickness of said exhaust slit at approx. 2 mm to approx. 4 mm.

40. The method according to claim 29, wherein the gas switching process comprises the steps of:

(I) when a process gas is introduced as the gas into said gas-dispersion guide, decreasing conductance of the second gas flow path to nearly minimum, thereby exhausting the gas through the first gas flow path passing via the substrate;

(II) when a purge gas is introduced as the gas into said gas-dispersion guide, increasing conductance of the second gas flow path to nearly maximum, thereby exhausting said process gas through the second gas flow path not passing via the substrate;

(III) sequentially, repeating steps (I) and (II) for subsequent process gases, wherein one cycle is completed when all process gases have passed through the substrate; and

(IV) repeating the cycle until a thickness of a thin film to be formed on the substrate reaches a given value.

41. The method according to claim 40, wherein the time required for one cycle is approx. 0.5 seconds to approx. 3 seconds.

42. The method according to claim 40, wherein each cycle is controlled to deposit each atomic layer.

43. The method according to claim 40, wherein the gas switching is executed by controlling minimum conductance (Cpse) of the second gas flow path, conductance of the first gas flow path (Cpde), and maximum conductance of the second gas flow path (Cse) in the following ratio:

Cpse;

Cpde;

Cse=1 or less;

5-20;

100.

50. A thin-film formation apparatus comprising:

a reaction chamber to be evacuated;

a placing portion on which a substrate is placed inside said reaction chamber;

a gas-dispersion guide installed above said placing portion for supplying a gas onto a surface of said substrate;

a gas-supply port for introducing a gas into said gas-dispersion guide,

a gas-dispersion plate being disposed on a substrate side of said gas-dispersion guide and having multiple gas discharge pores;

an exhaust port for exhausting a gas supplied from said gas-dispersion plate to the substrate surface radially from a perimeter of said placing stand; and

a purge-gas ring disposed concentrically and at a given distance apart from a side portion of said placing stand,

wherein a purge-gas slit is constituted by the side portion of said placing stand and said purge-gas ring, and a gas flow path is constituted by communicatively connecting said exhaust port with a lower space below said placing stand via said slit.

51. The method according to claim 50, wherein said purge-gas slit has a thickness of approx. 0.5 mm to approx. 1.5 mm and a length of approx. 15 mm to approx. 40 mm in said placing stand'"'"'s axial direction.

52. The method according to claim 50, wherein an annular slit is disposed, as an entrance of said exhaust port, concentrically outside said placing stand and substantially and nearly at the same level as that of a substrate-placing surface of said placing stand.

53. The method according to claim 50, wherein said purge-gas ring is provided around the side portion of said placing stand at a lower position than the substrate-placing surface;

and an exhaust ring is disposed above said purge-gas ring along and concentrically with the side portion of said placing stand, thereby constituting an exhaust slit which is an annular slit disposed as an entrance of said exhaust port between said exhaust ring and said purge-gas ring.

54. The method according to claim 53, wherein said exhaust slit has a thickness larger than a thickness of said purge-gas slit.

55. The method according to claim 54, wherein said exhaust slit has a thickness of approx. 2 mm to approx. 4 mm.

56. A method for forming a thin film comprising the steps of:

placing a substrate on a placing portion inside a reaction chamber evacuated;

introducing a gas from a gas-supply port to a gas-dispersion guide installed above said placing portion;

supplying the gas onto a substrate surface via a gas-dispersion plate disposed on a substrate side of the gas-dispersion guide and having multiple gas-discharge pores;

exhausting the gas supplied from said gas-dispersion plate onto the substrate surface from an exhaust port provided annularly around said placing stand;

suppressing diffusion of the gas to a lower space below said placing stand by introducing a purge gas from the lower space below said placing stand through a purge-gas slit and exhausting the purge gas from said exhaust port, said purge-gas slit being formed by a purge-gas ring disposed concentrically with said placing stand and at a given distance apart from a side portion of said placing stand.

57. The method according to claim 56, wherein the purge-gas slit has a thickness of approx. 0.5 mm to approx. 1.5 mm and a length of approx. 15 mm to approx. 40 mm in said placing stand'"'"'s axial direction.

58. The method according to claim 56, wherein an annular slit is disposed, as an entrance of said first exhaust port, concentrically outside said placing stand and substantially and nearly at the same level as that of a substrate-placing surface of said placing stand.

59. The method according to claim 56, wherein said purge-gas ring is provided around the side portion of said placing stand at a lower position than the substrate-placing surface;

and an exhaust ring is disposed above the purge-gas ring concentrically with said placing stand and along the side portion of said placing stand, thereby constituting an exhaust slit which is an annular slit disposed between said exhaust ring and said purge-gas ring as an entrance of said first exhaust port.

60. The method according to claim 59, wherein said exhaust slit has a thickness larger than a thickness of said purge-gas slit.

61. The method according to claim 60, wherein said exhaust slit has a thickness of approx. 2 mm to approx. 4 mm.