Gas mixer and manifold assembly for ALD reactor

• US 20050092247A1
• Filed: 08/30/2004
• Published: 05/05/2005
• Est. Priority Date: 08/29/2003
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM America Incorporated (ASM International NV)
• Inventors: Verghese, Mohith, Schmidt, Ryan M.
• Granted Patent: US 8,152,922 B2
• Time in Patent Office: Days
• US Class Current: 118/715
• CPC Class Codes: C23C 16/4408 by purging residual gases from the reaction chamber or gas lines
• CPC Class Codes: C23C 16/455 characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
• CPC Class Codes: C23C 16/45512 Premixing before introduction in the reaction chamber
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: C23C 16/45527 characterized by the ALD cycle, e.g. different flows or temperatures during half-reactions, unusual pulsing sequence, use of precursor mixtures or auxiliary reactants or activations
• CPC Class Codes: C23C 16/45544 characterized by the apparatus
• CPC Class Codes: C23C 16/45561 Gas plumbing upstream of the reaction chamber
• CPC Class Codes: C23C 16/45563 Gas nozzles
• CPC Class Codes: C23C 16/45565 Shower nozzles
• CPC Class Codes: C23C 16/45591 Fixed means, e.g. wings, baffles
• CPC Class Codes: Y10T 137/87652 With means to promote mixing or combining of plural fluids

Abstract

A system and method for mixing a plurality of gases for an atomic layer deposition (ALD) reactor. The mixer is configured to mix the plurality of gases while minimizing the potential for re-circulation within the mixer. The mixer is further configured to maintain the flow velocity of the plurality of gases as the gases pass through the mixer.

Claims

1. A mixer for mixing a reactant gas with a buffer gas in a reactor, the mixer comprising:

a housing;

a chamber located within the housing, the chamber having a flow axis through the housing;

an outlet port from the chamber, the outlet port being aligned with the flow axis;

a first port into the chamber, the first port being aligned at an angle of at least 45 degrees relative to the flow axis; and

a second port into the chamber, the second port being aligned at an angle of at least 45 degrees relative to the flow axis.

2. The mixer of claim 1, wherein the chamber comprises a lower trough portion, and wherein the first and second ports are aligned tangential to the trough portion.

3. The mixer of claim 1, wherein the chamber substantially tapers along the flow axis in a direction towards the outlet port.

4. The mixer of claim 1, wherein at least a portion of the chamber comprises a conically shaped surface.

5. A mixer for receiving pulses of gas for use during atomic layer deposition (ALD), the mixer comprising:

a housing having a first inlet, a second inlet, and enclosing means for mixing the received pulses of gas passing along a flow axis, wherein the first and second inlets are aligned tangential to the flow axis.

6. The mixer of claim 5, wherein the means for mixing comprises an insert, the insert being configured to cause pulses of gas passing therethrough to swirl around the flow axis.

7. The mixer of claim 5, wherein the means for mixing substantially tapers along the flow axis.

8. The mixer of claim 5, wherein the means for mixing comprises a trough portion, and wherein the first and second inlets are aligned tangential to the trough portion.

9. An atomic layer deposition (ALD) thin film deposition apparatus, comprising:

a housing;

a chamber located within the housing and having a flow axis through the housing;

a reactor in flow communication with the chamber and configured to deposit a thin film on a wafer mounted therein;

a first reactant gas line configured to supply a first reactant gas to the chamber at an angle relative to the flow axis;

a second reactant gas line configured to supply a second reactant gas to the chamber at an angle relative to the flow axis;

a first buffer gas line in flow communication with the second reactant gas line at a first coupling and configured to supply a first portion of a first buffer gas to the chamber via the second reactant gas line, where the first buffer gas selectively impedes the second reactant gas from reaching the chamber.

10. The ALD thin film deposition apparatus of claim 9 further comprising a second buffer gas line in flow communication with the second reactant gas line at a second coupling and configured to route a second portion of the first buffer gas from the second reactant gas line.

11. The ALD thin film deposition apparatus of claim 9, wherein the chamber has a generally tapering shape.

12. The ALD thin film deposition apparatus of claim 9, wherein the housing comprises a first inlet in flow communication with the first reactant gas line and a second inlet in flow communication with the second reactant gas line, wherein the first inlet is parallel to the second inlet.

13. The ALD thin film deposition apparatus of claim 9, wherein the flow path through the first inlet is substantially parallel to the wafer.

14. The ALD thin film deposition apparatus of claim 9, wherein an inner surface of the housing has a conical shape.

15. The ALD thin film deposition apparatus of claim 9, wherein the housing comprises a first conical surface and a second surface, the second surface being located substantially equidistant from the first surface and forming at least a portion of the chamber.

16. The ALD thin film deposition apparatus of claim 9, wherein the housing comprises a first surface and a second surface, the first and second surfaces having conical shapes forming at least a portion of the chamber.

17. The ALD thin film deposition apparatus of claim 16, wherein the first conical surface is parallel to the second conical surface.

18. The ALD thin film deposition apparatus of claim 9, wherein the housing comprises an insert configured to swirl the first reactant gas.

19. The ALD thin film deposition apparatus of claim 18, wherein the insert forms a surface of the chamber.

20. The ALD thin film deposition apparatus of claim 18, wherein at least a portion of the insert has a conical shape.

21. The ALD thin film deposition apparatus of claim 18, wherein at least a portion of the insert has a parabolic shape.

22. The ALD thin film deposition apparatus of claim 18, wherein at least a portion of the insert has a hemispherical shape.

23. A housing for mixing a first gas with a second gas in a vapor deposition reactor, the housing comprising:

an upstream member comprising,

an insert member having a base, a distal end located downstream of the base, and a first mixing surface located between the base and the distal end,

a second mixing surface located parallel to a portion of the first mixing surface,

a trough circumscribing the base and forming a transition surface between the first and second mixing surfaces,

an inlet; and

a downstream member in flow communication with the upstream member and having a generally tapering inner surface, the first and second mixing surfaces, the trough, and the tapering inner surface together forming at least a portion of a chamber.

24. The mixer of claim 23, wherein a flow path through the inlet is substantially aligned with the trough.

25. The mixer of claim 23, wherein a flow area of the chamber decreases in a flow direction towards the downstream member.

26. The mixer of claim 23, wherein the first mixing surface is parallel to the second mixing surface.

27. The mixer of claim 23, wherein the first mixing surface has a conical shape.

28. The mixer of claim 27, wherein the second mixing surface has a conical shape.

29. A method of performing atomic layer deposition (ALD) in a reactor, the method comprising:

flowing a first reactant gas through a first reactant gas line and towards a housing having a first generally tapering surface;

flowing a second reactant gas through a second reactant gas line and towards the housing;

flowing a buffer gas through a buffer gas line and into the first reactant gas line;

forming a first gas buffer in the first reactant gas line to prevent the first reactant gas from reaching the housing;

mixing the second reactant gas with a first portion of the buffer gas in the housing to form a mixture;

swirling the mixture in the housing; and

flowing the mixture into a deposition chamber.

30. The method of claim 29, further comprising:

exhausting a non-deposited portion of the mixture from the deposition chamber;

exhausting a second portion of the buffer gas from the first gas buffer; and

purging the deposition chamber.

31. The method of claim 29, wherein the housing further comprises a second generally tapering surface.

32. The method of claim 29, further comprising:

reducing the flow of the buffer gas into the first reactant gas line so that the first reactant gas enters the housing;

flowing a second buffer gas through a second buffer gas line and into the second reactant gas line;

forming a second gas buffer in the second reactant gas line to prevent the second reactant gas from entering the housing;

mixing the first reactant gas with a first portion of the second buffer gas in the housing to form a second mixture;

swirling the second mixture in the housing;

reacting the second mixture with the deposit on the wafer;

exhausting a non-deposited portion of the second mixture from the deposition chamber;

exhausting a second portion of the second buffer gas from the second gas buffer; and

purging the deposition chamber.

33. A gas distribution system for use with an Atomic Layer Deposition (ALD) chamber, the gas distribution system comprising:

a first reactant line;

a second reactant line;

a housing communicating with the first and second reactant lines and a source of inert gas, and configured to form a mixture by swirling a reactant gas from the second reactant line with a buffer gas from the first buffer line;

a transfer tube in flow communication with the housing and configured to collect the mixture;

an intake plenum in flow communication with the transfer tube and configured to distribute the mixture into a deposition chamber; and

an exhaust launder communicating with the deposition chamber and configured to collect and exhaust the mixture from the deposition chamber.

34. The gas distribution system of claim 33, further comprising:

a cover plate located below the first and second reactant lines and the transfer tube, and having a passageway in flow communication with the intake plenum; and

a base plate located below the cover plate to form a flow path for the mixture to enter the deposition chamber.

35. The gas distribution system of claim 33, further comprising a third reactant line.

36. The gas distribution system of claim 33, wherein the housing comprises:

an upstream member comprising,

an insert member having a base, a distal end located downstream of the base, and a first mixing surface located between the base and the distal end,

a second mixing surface located parallel to a portion of the first mixing surface,

a trough circumscribing the base and forming a transition surface between the first and second mixing surfaces,

an inlet; and

a downstream member in flow communication with the upstream member and having a generally tapering inner surface, the first and second mixing surfaces, the trough, and the tapering inner surface together forming at least a portion of a chamber.

37. The gas distribution system of claim 33, further comprising:

a first buffer line coupled to the first reactant line at a first coupling; and

a second buffer line coupled to the first reactant line at a second coupling, wherein a location of the first coupling is different than a location of the second coupling.

38. The gas distribution system of claim 37, wherein the first coupling is located between the second coupling and the housing such that the buffer gas entering the first reactant gas line from the first buffer line impedes the flow of the reactant gas through the first reactant gas line.

39. A mixer for mixing a reactant gas with a buffer gas in an atomic layer deposition (ALD) reactor, the mixer comprising:

a housing with a first inner surface;

an insert located within the housing and having a transition surface between the outer surface and the first inner surface, wherein a portion of the insert has a generally tapering cross-section;

a mixing chamber formed between the generally tapering cross-section, the first inner surface, and the trough;

a first inlet passing through the housing and configured to couple the mixing chamber with a first reactant gas line; and

a second inlet passing through the housing and configured to couple the mixing chamber with a second reactant gas line.

40. The mixer of claim 39, wherein the first reactant gas line is coupled to a first buffer line and a second buffer line.