Plasma enhanced atomic layer deposition (PEALD) equipment and method of forming a conducting thin film using the same thereof

• US 7,138,336 B2
• Filed: 08/06/2001
• Issued: 11/21/2006
• Est. Priority Date: 08/06/2001
• Status: Expired due to Term

• Current Assignee: ASM Korea Ltd. (ASM International NV)
• Original Assignee: Asm Genitech Korea Ltd. (ASM International NV)
• Inventors: Oh, Min Sub, Park, Hyung Sang, Lee, Chun Soo
• Primary Examiner(s): GHYKA, ALEXANDER G
• Application Number:
  US10/486,311
• Publication Number:
  US 20040231799A1
• Time in Patent Office: 1,933 Days
• Field of Search: 438/680, 438/685, 438/695, 118/729
• US Class Current: 438/680
• CPC Class Codes: C23C 16/4412 Details relating to the exhausts, e.g. pumps, filters, scrubbers, particle traps
• CPC Class Codes: C23C 16/45508 Radial flow
• CPC Class Codes: C23C 16/45519 Inert gas curtains
• CPC Class Codes: C23C 16/4554 Plasma being used non-continuously in between ALD reactions C23C16/56 takes precedence
• CPC Class Codes: C23C 16/45544 characterized by the apparatus
• CPC Class Codes: C23C 16/45565 Shower nozzles
• CPC Class Codes: C23C 16/45591 Fixed means, e.g. wings, baffles
• CPC Class Codes: C23C 16/50 using electric discharges generation and control of plasma in discharge tubes for surface treatment H01J37/32, H01J37/34
• CPC Class Codes: C23C 16/5096 Flat-bed apparatus
• CPC Class Codes: H01J 37/32082 Radio frequency generated discharge H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence
• 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: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 21/3141 Deposition using atomic layer deposition techniques [ALD]
• CPC Class Codes: H01L 21/318 composed of nitrides

Abstract

A plasma enhanced atomic layer deposition (PEALD) apparatus and a method of forming a conductive thin film using the same are disclosed. According to the present invention of a PEALD apparatus and a method, a process gas inlet tube and a process gas outlet tube are installed symmetrically and concentrically with respect to a substrate, thereby allowing the process gas to flow uniformly, evenly and smoothly over the substrate, thereby forming a thin film uniformly over the substrate. A uniquely designed showerhead assembly provides not only reduces the volume of the reactor space, but also allows the process gases to flow uniformly, evenly and smoothly throughout the reation space area and reduces the volume of the reaction space, and the smaller volume makes it easier and fast to change the process gases for sequential and repeated process operation.

Claims

1. A plasma enhanced atomic layer deposition (PEALD) apparatus for depositing a thin film on a substrate, the apparatus comprising:

a substrate carrier for supporting a substrate;

a reactor wall defining the interior of a reactor together with said substrate carrier and said reactor wall having an opening at the top thereof;

a gas inlet tube for supplying a gas into said reactor;

a showerhead assembly to which said gas inlet tube is connected and installed within said reactor wall and defining a reaction space together with said substrate carrier and said showerhead assembly for supplying a gas to said reaction space;

a micro-feeding tube assembly made of insulating materials mounted between said gas inlet tube and the showerhead assembly for preventing generation of plasma due to potential difference between said gas inlet tube and the showerhead assembly while maintaining flow of gas supplied through said gas inlet tube, the micro feeding tube having a plurality of small tubes mounted in parallel, the plurality of small tubes configured to suppress plasma generation therein;

a gas outlet tube for discharging a gas from the reaction space; and

a radio frequency (RF) connection terminal for generating plasma.

2. The apparatus of claim 1, wherein the plurality of tubes in the micro-feeding tube assembly each have a diameter and a length small enough to prevent generation of plasma.

3. The apparatus of claim 1, wherein the gas inlet tube is inserted into the opening at the top of the reactor wall with a diameter less than the opening of the reactor wall, and the gas outlet tube is installed in the opening so that the gas supplied to the reaction space passes through a space between the reactor wall and the showerhead assembly and is discharged through a gap between the reactor wall and the gas inlet tube.

4. The apparatus of claim 1, wherein the RF connection terminal is connected to the showerhead assembly through the reactor wall, and is electrically insulated form the reactor wall.

5. The apparatus of claim 1, further comprising a reactor body having a gas inlet port and a gas outlet port that can open and shut, the reactor body forming an outer wall surrounding a predetermined region of the reactor wall and the substrate support.

6. The apparatus of claim 5, wherein the RF connection terminal is connected to the showerhead assembly through the reactor body and the reactor wall in order to apply RF power, and is electrically insulated from the reactor body and the reactor wall.

7. The apparatus of claim 1, further comprising a gas sealer ring covering the substrate carrier and connecting to the reactor wall in order to provide sealing of the inner part of the reactor.

8. The apparatus of claim 1, further comprising a heater installed to surround the sidewall of the reactor wall.

9. The apparatus of claim 1, further comprising a heater installed underneath of the substrate carrier for heating the substrate.

10. The apparatus of claim 1, wherein the substrate carrier moves up and down so that the substrate is loaded into or unloaded from the reaction space.

11. A plasma enhanced atomic layer deposition (PEALD) apparatus for depositing a thin film on a substrate, the apparatus comprising:

a substrate carrier for supporting the substrate;

a reactor wall defining the interior of the reactor together with the substrate carrier and the reactor wall having an opening at the top thereof;

a gas inlet tube for supplying a gas into the reactor;

a showerhead assembly to which the gas inlet tube is connected and is installed within the reactor wall for defining a reaction space together with the substrate carrier and the showerhead assembly for supplying a gas to the reaction space;

a showerhead insulating wall surrounding the top part and the sides of the showerhead assembly;

a plasma generation barrier wall installed between the showerhead insulating wall and the reactor wall and having the same potential as the reactor wall, plasma generation barrier wall having a gap to the showerhead insulating wall;

a gas outlet tube for discharging a gas from the reaction space; and

a radio frequency (RF) connection terminal connected to the showerhead in order to apply an RF power.

12. The apparatus of claim 11, wherein an inert gas is forced to flow through the gap between the plasma generation barrier wall and the showerhead insulating wall, thereby blocking the gas supplied to the reaction space from being flown into the gap between the plasma generation barrier wall and the showerhead insulating wall and thus preventing formation of a conductive thin film on the outside surface of the showerhead insulating wall.

13. The apparatus of claim 12, wherein the RF connection terminal has the shape of a tube so that an inert gas can flow, into it and a gap is formed between the plasma generation barrier wall and the showerhead insulating wall, thereby providing a passage for an inert gas.

14. The apparatus of claim 13, further comprising a symmetric buffered passage ways provided by forming a set of trenches on the top part of the showerhead insulating wall or the bottom part of the plasma generation barrier wall so that the inert gas supplied through the RF connection terminal flows uniformly through the gasp between the plasma generation barrier wall and the showerhead insulating wall.

15. The apparatus of claim 11, wherein the RF connection terminal is connected to the showerhead assembly through the reactor wall, the plasma generation barrier wall, and the showerhead insulating wall, and is electrically insulated from the reactor wall as well as the plasma generation barrier wall.

16. The apparatus of claim 11, further comprising a reactor body having a gas inlet tube and a gas outlet tube with an on-off switch, respectively, the reactor body forming an outer wall surrounding a specified region of the reactor wall and the substrate carrier.

17. The apparatus of claim 16, wherein the RF connection terminal is connected to the showerhead assembly through the reactor body, the reactor wall, the plasma generation barrier wall, and the showerhead insulating wall in order to apply an RF power, and is electrically insulated from the reactor body, the reactor wall, and the plasma generation barrier wall.

18. The apparatus of claim 11, wherein the gas inlet tube is inserted into the opening at the top of the reactor wall with a diameter less than the opening of the reactor wall, and the gas outlet tube is installed in the opening so that the gas supplied to the reaction space passes through a space (gap) between the reactor wall and the plasma generation barrier wall, and is discharged through a gap between the reactor wall and the gas inlet tube.

33. The apparatus of claim 11, further comprising a reactor body having an inert gas inlet port and an inert gas outlet port with on/off valves and surrounding reactor parts including said substrate carrier.

34. The apparatus of claim 33, wherein the RF connection terminal is connected to the showerhead assembly through the reactor body, the reactor wall, the plasma generation barrier wall, and the showerhead insulating wall in order to apply an RF power, and is electrically insulated from the reactor body, the reactor wall, and the plasma generation barrier wall.

19. A plasma enhanced atomic layer deposition (PEALD) apparatus for depositing a thin film on a substrate, the apparatus comprising:

a substrate carrier for supporting the substrate;

a reactor wall defining the interior of reactor together with said substrate carrier and having an opening at the top thereof;

a gas inlet tube for supplying a gas into said reactor;

a showerhead assembly having a volume adjusting horn for minimizing the volume of a reaction space and for allowing smooth and even flow of a gas;

a gas outlet tube for removing gas from said reaction space; and

a radio frequency (RF) power connection terminal connected to the showerhead assembly in order to apply RF power.

20. The apparatus of claim 19, further comprising a showerhead insulating wall surrounding the top and sides of said showerhead assembly.

21. The apparatus of claim 19, wherein said RF power connection terminal is connected to said volume adjusting horn through said reactor wall, and is electrically insulated from said reactor wall.

22. The apparatus of claim 19, further comprising a reactor body having an inert gas inlet port and an inert gas outlet port with on/off valves and surrounding reactor parts including said substrate carrier.

23. The apparatus of claim 22, wherein the RF connection terminal is connected to the volume adjusting horn through said reactor body and said reactor wall in order to apply RF power, and is electrically insulated from said reactor body and said reactor wall.

24. The apparatus of claim 19, wherein a gas inlet tube is installed in the opening at the top center of said reactor wall and a gas outlet tube is installed in the opening at the top center of said reactor wall and a gas outlet tube is installed in the opening at the top center, concentrically outside of said gas inlet tube and flows through the interior of said reactor and then exhausted through said gas outlet tube.

25. A plasma enhanced atomic layer deposition (PEALD) apparatus for depositing a thin film on a substrate, the apparatus comprising:

a substrate carrier for supporting a substrate;

a reactor wall defining the interior of the reactor together with said substrate carrier and having an opening at the top thereof;

a gas inlet tube for supplying a gas into said reactor;

a showerhead, assembly to which a gas inlet is connected and installed within said reactor wall defining a reaction space together with said substrate carrier and for supplying a gas to said reaction space;

a micro-feeding tube assembly made of insulating material disposed between the gas inlet tube and the shower head for preventing generation of plasma due to potential difference between the gas inlet tube and the shower head while maintaining the flow of gas introduced from the gas inlet tube, the micro feeding tube having a plurality of narrow tubes connected in parallel;

a showerhead insulating wall surrounding the top and sides of said showerhead assembly;

a plasma generation barrier wall installed with a gap between said showerhead insulating wall and said reactor wall and having no potential difference with respect to said reactor wall;

a gas outlet tube for removing a gas from said reaction space; and

a radio frequency (RF) power connection terminal connected to the showerhead assembly for applying RF power.

26. The apparatus of claim 25, wherein the showerhead assembly includes a gas dispersion perforated grid and a volume adjusting horn connected to a micro-feeding tube assembly through a hole at the center of said volume adjusting horn.

27. The apparatus of claim 25, wherein each of the plurality of the small tubes of the micro-feeding tube assembly has a diameter small enough to prevent plasma generation.

28. The apparatus of claim 25, wherein an inert gas forced to flow through the gap between the plasma generation barrier wall and the showerhead insulting wall, thereby blocking the gas supplied to the reaction space from being flow into the gap between the plasma generation barrier wall and the showerhead insulating wall and thus preventing formation of a conductive thin film on the outside surface of the showerhead insulating wall.

29. The apparatus of claim 28, wherein the RF connection terminal has the shape of a tube so that an inert gas can flow, into it and a gap is formed between the plasma generation barrier wall and the showerhead insulating wall, thereby providing a passage for an inert gas.

30. The apparatus of claim 29, further comprising a symmetric buffered passage ways provided by forming a set of trenches on the top part of the showerhead insulating wall or the bottom part of the plasma generation barrier wall so that the inert gas supplied through the RF connection terminal tube flows uniformly through the gap between the plasma generation barrier wall and the showerhead insulating wall.

31. The apparatus of claim 25, wherein the gas inlet tube is inserted into the opening at the top of the reactor wall with a diameter less than the opening of the reactor wall, and the gas outlet tube is installed in the opening so that the gas supplied to the reaction space passes through a space between the reactor wall and the plasma generation barrier wall, and is discharged through a gap between the reactor wall and the gas inlet tube.

32. The apparatus of claim 25, wherein the RF connection terminal is connected to the showerhead assembly through the reactor wall, the plasma generation barrier wall, and the showerhead insulating wall, and is electrically insulated form the reactor wall as well as the plasma generation barrier wall.

35. The apparatus of claim 25, further comprising a gas sealer ring covering the substrate carrier and connecting to the reactor wall in order provide sealing of the inner part of the reactor.

36. The apparatus of claim 25, further comprising a heater installed to surround the sidewall of the reactor wall.

37. The apparatus of claim 25, further comprising a heater installed underneath of the substrate carrier for heating the substrate.

38. The apparatus of claim 25, wherein the substrate carrier moves up and down so that the substrate is loaded into or unloaded from the reaction space.

39. A method of forming a conductive thin film on a substrate, the method comprising the steps of:

preparing a process gas containing desired metallic components;

loading a substrate into a reaction space defined in part by a gas injection assembly, and a reactor wall, the gas injection assembly having a gas injection face and an adjacent side wall, the gas injection assembly protruding from the reactor wall such that a space is formed between the side wall of the gas injection assembly and the reactor wall;

supplying said source gas containing metallic components to said reaction space through a gas inlet tube;

ceasing to supply said source gas and supplying H₂ or H₂ containing purge gas to said reaction space through said gas inlet tube;

generating plasma to activate said purge gas for a specified period of time while said purge gas is continuously supplied;

exhausting gas from the reaction space through the space between the gas injection assembly side wall and the reactor wall; and

purging said reaction space using said purge gas;

wherein the step of supplying said source gas, the step of supplying said purge gas, the step of generating plasma, and the step of purging are repeated specified number of times.

40. The method of claim 39, wherein a micro-feeding tube assembly in which a plurality of small tubes are connected in parallel is installed at the end of said gas inlet tube, and the process gases are supplied through said gas inlet tube and then through said micro-feeding tube assembly.

41. The method of claim 39, wherein said source gas includes Titanium Tetra-Chloride (TiCl₄).

42. The method of claim 39, wherein the gas injection assembly comprises a showerhead assembly.

43. The method of claim 39, further comprising discharging the exhausted gas through a gap between the reactor wall and the gas inlet tube.

44. The method of claim 39, wherein said conductive thin film is titanium nitride (TiN).

45. The method of claim 39, wherein said purge gas includes H₂ and N₂ gases.

46. The method of claim 39, wherein said conductive thin film is titanium metal.