Methods for plasma processing

• US 9,096,932 B2
• Filed: 04/14/2014
• Issued: 08/04/2015
• Est. Priority Date: 07/08/2009
• Status: Active Grant

• Current Assignee: Aixtron AG
• Original Assignee: Aixtron Inc. (Aixtron AG)
• Inventors: Savas, Stephen E., Galewski, Carl, Wiesnoski, Allan B., Mantripragada, Sai, Joh, Sooyun
• Primary Examiner(s): MILLER, JR, JOSEPH ALBERT
• Application Number:
  US14/251,851
• Publication Number:
  US 20140212601A1
• Time in Patent Office: 477 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: C23C 16/24 Deposition of silicon only
• CPC Class Codes: C23C 16/26 Deposition of carbon only
• CPC Class Codes: C23C 16/345 Silicon nitride
• CPC Class Codes: C23C 16/40 Oxides
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/407 of zinc, germanium, cadmium, indium, tin, thallium or bismuth
• CPC Class Codes: C23C 16/4412 Details relating to the exhausts, e.g. pumps, filters, scrubbers, particle traps
• CPC Class Codes: C23C 16/45504 Laminar flow
• CPC Class Codes: C23C 16/45519 Inert gas curtains
• CPC Class Codes: C23C 16/45591 Fixed means, e.g. wings, baffles
• CPC Class Codes: C23C 16/466 using thermal contact gas
• 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 16/503 using dc or ac discharges
• CPC Class Codes: C23C 16/505 using radio frequency discharges
• CPC Class Codes: C23C 16/545 for coating elongated substrates
• CPC Class Codes: H01J 37/32036 AC powered
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• 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 37/32541 Shape
• CPC Class Codes: H01L 21/67069 : for drying etching

Abstract

Apparatus and method for plasma-based processing well suited for deposition, etching, or treatment of semiconductor, conductor or insulating films. Plasma generating units include one or more elongated electrodes on the processing side of a substrate and a neutral electrode proximate the opposite side of the substrate. Gases may be injected proximate a powered electrode which break down electrically and produce activated species that flow toward the substrate area. This gas then flows into an extended process region between powered electrodes and substrate, providing controlled and continuous reactivity with the substrate at high rates with efficient utilization of reactant feedstock. Gases are exhausted via passages between powered electrodes or electrode and divider.

Claims

1. A method for plasma-based coating of thin films on a substrate, said method comprising:

providing a chamber, connecting it to a vacuum pump and maintaining a gas pressure in a range of 50 Pascals to 2000 Pascals in said chamber;

positioning a plurality of electrodes within said chamber, whose lengths are greater than their width or height, and positioning a support for substrates, with at least one said electrode having a part of its surface opposite said support for said substrate, the lengths extending parallel to a plane defined by said support; and

placing a substrate on said support such that a side of said substrate to be coated faces at least one said electrode, and where the minimum gap between said electrode and said substrate is less than the electrode width; and

maintaining the part of said substrate adjacent said pedestal at a temperature less than 200°

C.; and

injecting a first gas into the space between two said electrodes to flow towards said substrate, said first gas comprising a compound of at least one of;

nitrogen and oxygen;

but no silicon-based compound;

providing AC power to at least one of said two electrodes to form a plasma, activating said first gas in the space between said two electrodes, and forming a plasma between at least one of said electrodes and said substrate that provides ion bombardment of said substrate; and

injecting a second gas from within at least one said electrode into said flowing activated first gas to form a mixed gas, said second gas comprising at least one of;

a silicon-containing compound and a metal containing compound; and

wherein said mixed gas forms a thin film on the substrate that contains said at least one of;

a metal oxide, metal nitride, metal oxynitride, silicon oxide, silicon nitride and silicon oxynitride on said substrate.

2. The method of claim 1 wherein said AC power is one of radiofrequency (RF) or very high frequency (VHF) power.

3. The method of claim 1 wherein said electrode length is greater than four times the electrode width or electrode height.

4. The method of claim 1 wherein said minimum gap between said electrodes and said substrate on said support structure being less than the width and less than the height of said electrodes.

5. The method of claim 1 wherein said inter-electrode gap is between 5 mm and 20 mm.

6. The method of claim 1 wherein the flow of said mixed gas adjacent the front of at least one said electrode is non-recirculating.

7. The method of claim 1 wherein said mixed gas after flowing past the front of at least one said electrode, flows adjacent a second side of at least one electrode to an exhaust.

8. The method of claim 1 wherein the flow of said mixed gas is around at least one of said electrodes to an exhaust.

9. The method of claim 1 wherein a first power density in said inter-electrode gap is higher than a second power density between said electrode and said substrate;

and wherein a power ratio between said first power density and said second power density is less than a 10;

1.

10. The method of claim 9 wherein said power ratio is less than a factor of 5.

11. The method of claim 1 wherein a dielectric film is deposited on said substrate.

12. The method of claim 1 wherein a silicon-containing transparent film deposited on said substrate.

13. The method of claim 1 wherein a transparent, metal-containing, conducting film is deposited on said substrate.

14. A method for plasma-based deposition of silicon-based films on a substrate, said method comprising:

providing a chamber, connecting it to a vacuum pump and maintaining a gas pressure of less than 2,000 Pascals in said chamber;

positioning at least one electrode and at least one other element both with lengths that are greater than the electrode width or electrode height within said chamber, said electrode having a first side facing said element and a front side facing a support structure for said substrates; and

placing said substrate on said support structure such that a side of said substrate to be coated faces said front side of said electrode, and wherein the minimum gap between said electrode and said substrate on said support is less than the electrode width, the lengths extending parallel to a plane defined by said support;

maintaining said substrate at a temperature under 200 degrees Celsius; and

injecting a first reactant gas comprising compounds not containing silicon, which gas flows toward said substrate adjacent said first side of said electrode;

providing AC power to said electrode to form a plasma by activating said first gas in a gap between said electrode and said element, and forming a plasma adjacent the front side of said electrode providing ion bombardment of said substrate;

injecting a second gas into said flowing activated first gas to form a mixed gas, said second gas comprising a silicon-containing compound, and depositing a silicon-based thin film upon the substrate; and

wherein said mixed gas flows adjacent said front side of said electrode without recirculation.

15. The method of claim 14 wherein said AC power includes at least one of:

radiofrequency (RF) and very high frequency (VHF) power.

16. The method of claim 14 wherein after flowing adjacent the front of said electrode the mixed gas flows adjacent a second side of said electrode, opposite the first side, to an exhaust.

17. The method of claim 14 wherein said electrode length is greater than four times the electrode width or electrode height.

18. The method of claim 14 wherein said minimum gap between said electrodes and said substrate on said support structure is less than the width or less than the height of the plurality of electrodes.

19. The method of claim 14 wherein said gap between said first side of said electrode and said element is between 5 mm and 20 mm.

20. The method of claim 14 wherein said mixed gas after flowing adjacent the front side of said electrode flows adjacent a second side of said electrode to said exhaust.

21. The method of claim 14 wherein said first gas is activated by plasma prior to flowing adjacent said electrode.

22. The method of claim 14 wherein said first gas comprises a compound of at least one of nitrogen or oxygen;

and

wherein said second gas contains a silicon compound to form a film with said first gas that contains at least one of;

silicon oxynitride and silicon nitride.

23. The method of claim 14 wherein a dielectric film is deposited containing at least one of:

silicon nitride, silicon oxynitride, and silicon oxide.

24. The method of claim 14 wherein a transparent, metal-containing, electrically conducting film is deposited on said substrate.

25. A method for plasma-based coating of thin films on a substrate, said method comprising:

providing a chamber, connecting it to a vacuum pump and maintaining a gas pressure in a range of 50 Pascals to 2000 Pascals in said chamber;

positioning a plurality of electrodes within said chamber, whose lengths are greater than their width or height, and positioning a support for substrates, with at least one said electrode having a front side opposite said support for said substrate, the lengths extending parallel to a plane defined by said support; and

placing a substrate on said support such that a side of said substrate to be coated faces at least one said electrode, and where the minimum gap between said electrode and said substrate is less than the electrode width; and

maintaining the part of said substrate adjacent said pedestal at a temperature less than 200°

C.; and

injecting a first gas into the space between opposing faces of said electrodes to flow towards said substrate;

providing AC power to at least one of said electrodes to form a plasma between said electrode and substrate providing ion bombardment of said substrate;

injecting a second gas from within at least one said electrode into said flowing first gas to form a mixed gas;

wherein said mixed gas deposits a thin film on said substrate; and

flows adjacent said front side of at least one said electrode without recirculation.

26. The method of claim 25 wherein said AC power is one of RF or VHF power.

27. The method of claim 25 wherein said electrode length is greater than four times the electrode width or electrode height.

28. The method of claim 25 wherein said minimum gap between said electrodes and said substrate on said support structure being less than the width or less than the height of the plurality of electrodes or less than both the height or width.

29. The method of claim 25 wherein said inter-electrode gap is between 5 mm and 20 mm.

30. The method of claim 25 wherein the flow of said mixed gas is around at least one of said electrodes to an exhaust.

31. The method of claim 25 wherein a first power density in said inter-electrode gap is higher than a second power density between said electrode and said substrate;

and

wherein a power ratio between said first power density and said second power density is less than a factor of 5.

32. The method of claim 25 wherein said first gas comprises a compound of at least one of nitrogen or oxygen;

and

wherein said second gas contains a silicon compound to form a film with said first gas that contains silicon oxynitride or silicon nitride.

33. The method of claim 25 wherein a dielectric film is deposited on said substrate.

34. The method of claim 25 wherein a transparent, metal-containing, electrically conducting film is deposited on said substrate.