Method for single chamber processing of PECVD-Ti and CVD-TiN films for integrated contact/barrier applications in IC manufacturing

{
  "publication_number": "US6274496B1",
  "country": "US",
  "kind": "B1",
  "title": "Method for single chamber processing of PECVD-Ti and CVD-TiN films for integrated contact/barrier applications in IC manufacturing",
  "abstract": "A single chamber method for depositing a stack including titanium and titanium nitride on a wafer surface. Titanium is deposited by plasma enhanced chemical vapor deposition and then plasma nitrided. Titanium nitride is subsequently deposited by a thermal chemical vapor deposition process. Advantageously, the temperatures of the substrate and showerhead as well as the internal chamber pressure are maintained at substantially constant values throughout deposition of the stack.",
  "claims": [
    "1. A method of depositing a stack that includes titanium and titanium nitride films on a wafer surface in a single chamber, comprising the steps of: placing a substrate having a wafer surface in a reaction chamber in spaced relation from a showerhead; depositing a titanium film onto the wafer surface in the chamber by forming within the chamber a first plasma of a gas mixture comprising a titanium halide and hydrogen; nitriding the deposited titanium film within the chamber by creating a second plasma of a gas selected from the group consisting of ammonia, nitrogen and a mixtures thereof; and depositing a titanium nitride film on the nitrided deposited titanium film in the chamber by a thermal CVD process using a gas mixture comprising a titanium halide and a nitrogen source gas.",
    "2. The method of claim 1, wherein the step of depositing a titanium film is performed with the wafer surface at a temperature of at least about 500° C.",
    "3. The method of claim 2, wherein the step of depositing a titanium film is performed with the wafer surface at a temperature from about 550° C. to about 700° C.",
    "4. The method of claim 2, wherein the step of depositing a titanium film is performed with the wafer surface at a temperature of at least about 580° C.",
    "5. The method of claim 1, wherein the step of nitriding the deposited titanium film is performed with the wafer surface at a temperature of at least about 500° C.",
    "6. The method of claim 2, wherein the step of nitriding the deposited titanium film is performed with the wafer surface at the same temperature as in the step of depositing a titanium film.",
    "7. The method of claim 6, wherein the step of depositing a titanium nitride film is performed with the wafer surface at the same temperature as in the steps of depositing a titanium film and nitriding the deposited titanium film.",
    "8. The method of claim 1, wherein the step of depositing a titanium nitride film is performed with the wafer surface at a temperature of at least about 580° C.",
    "9. The method of claim 1, wherein the steps of depositing a titanium film, nitriding the deposited titanium film and depositing a titanium nitride film are performed with the wafer surface at a substantially constant temperature of at least about 580° C.",
    "10. The method of claim 1, wherein the chamber has an internal pressure of about 1 torr to about 10 torr during the step of depositing a titanium film.",
    "11. The method of claim 1, wherein the chamber has an internal pressure of about 0.2 torr to about 20 torr during the step of depositing a titanium nitride film.",
    "12. The method of claim 1, wherein the chamber has a substantially constant internal pressure of about 1 torr to about 10 torr during the steps of depositing a titanium film, nitriding the deposited titanium film and depositing a titanium nitride film.",
    "13. The method of claim 12, wherein the constant internal temperature is about 5 torr.",
    "14. The method of claim 1, wherein the step of depositing a titanium film is performed with a showerhead at a temperature of about 425° C. to about 700° C.",
    "15. The method of claim 1, wherein the step of nitriding the deposited titanium film is performed with a showerhead at a temperature of about 425° C. to about 700° C.",
    "16. The method of claim 1, wherein the step of depositing a titanium nitride film is performed with a showerhead at a temperature of about 425° C. to about 700° C.",
    "17. The method of claim 1, wherein the steps of depositing a titanium film, nitriding the deposited titanium film and depositing a titanium nitride film are performed with the showerhead at a substantially constant temperature of between about 425° C. and about 700° C.",
    "18. The method of claim 1, wherein the showerhead is metal and the steps of depositing a titanium film, nitriding the deposited titanium film and depositing a titanium nitride film are performed with the showerhead at a substantially constant temperature of between about 425° C. and about 500° C.",
    "19. The method of claim 1 further comprising throughout the depositing of the titanium film, the nitriding of the deposited titanium film and the depositing of the titanium nitride film on the nitrided deposited titanium film in the chamber, maintaining the wafer surface at a substantially constant temperature, maintaining total gas pressure in the chamber at a substantially constant pressure, and maintaining showerhead temperature at a substantially constant temperature.",
    "20. The method of claim 1 further comprising throughout the depositing of the titanium film, the nitriding of the deposited titanium film and the depositing of the titanium nitride film on the nitrided deposited titanium film in the chamber, maintaining the wafer surface at a substantially constant temperature of at least about 580° C., maintaining total gas pressure in the chamber at a substantially constant pressure between about 1 torr and about 10 torr, and maintaining showerhead temperature at a substantially constant temperature of between about 425° C. and about 500° C.",
    "21. The method of claim 1 further comprising an initial step of pre-coating at least one of an internal chamber surface with TiN after cleaning the chamber surface.",
    "22. The method of claim 1, wherein the step of depositing the titanium nitride film comprises a first thermal CVD deposition under conditions of titanium tetrachloride depletion to a first thickness of titanium nitride, and a second thermal CVD deposition under conditions of titanium tetrachloride saturation to a final thickness of titanium nitride.",
    "23. The method of claim 1, wherein the wafer surface is silicon, and further comprising during the step of depositing the titanium film forming a layer of titanium suicide between the silicon wafer surface and the deposited titanium film.",
    "24. The method of claim 1, wherein the first and second plasmas are created within 25 mm of the wafer surface.",
    "25. The method of claim 1, wherein the steps of depositing a titanium film, nitriding the deposited titanium film and depositing a titanium nitride film are performed with the showerhead at a temperature of between about 150° C. to about 250° C.",
    "26. The method of claim 1, wherein the titanium halide is titanium tetrachloride.",
    "27. A method of depositing a stack that includes titanium and titanium nitride films onto a substrate surface in a single chamber comprising: placing a substrate having a surface in a reaction chamber in spaced relation from a showerhead; depositing a titanium film onto the surface in the chamber by plasma enhanced chemical vapor deposition; then nitriding the deposited titanium film in the chamber by forming a plasma of a gas selected from the group consisting of ammonia and nitrogen or a mixture of ammonia and nitrogen; then depositing a titanium nitride film on the nitrided deposited titanium film in the chamber by a thermal CVD process; and throughout the depositing of the titanium film, the nitriding of the deposited titanium film and the depositing of the titanium nitride film on the nitrided deposited titanium film in the chamber, maintaining the surface at a substantially constant temperature that is at least about 580° C., maintaining total gas pressure in the chamber at a substantially constant pressure that is between about 1 torr and about 10 torr, and maintaining showerhead temperature at a substantially constant temperature that is at least about 425° C.",
    "28. The method of claim 27 wherein the showerhead is metal and its temperature is maintained at a substantially constant temperature that is between about 425° C. and about 500° C.",
    "29. The method of claim 27, wherein the showerhead temperature is maintained at a substantially constant temperature that is between about 500° C. and about 700° C., and wherein the showerhead comprises a surface material that is resistant to corrosion at temperatures above about 500° C.",
    "30. The method of claim 27 wherein the depositing of the titanium nitride film on the nitrided deposited titanium film in the chamber includes: depositing titanium nitride by thermal CVD in an initial step in a titanium halide depletion regime with titanium halide flowing at a first flow rate in which titanium halide is diluted in a flow of gas that includes a nitrogen containing gas; and following deposition of titanium nitride by the initial step, increasing the flow rate of titanium halide to a flow rate in a saturation regime and thereby depositing titanium nitride in a second step over the titanium nitride deposited in the initial step.",
    "31. The method of claim 27, wherein the depositing of the titanium nitride film on the nitrided deposited titanium film in the chamber includes: depositing the titanium nitride film in an initial step in a titanium tetrachloride depletion CVD mode with titanium tetrachloride flowing at a flow rate of about 8 sccm, with ammonia flowing at a flow rate of about 80 sccm and with nitrogen flowing at a flow rate of about 1 liter per minute as a diluent at a pressure of about 5 torr to thereby form a layer of TiN about 100 to 500 angstroms thick; and then increasing the flow rate of titanium tetrachloride to a flow rate in a saturation regime of about 30 sccm with the flow rates of ammonia and of nitrogen remaining constant, thereby forming a further layer of TiN over the thin layer.",
    "32. The method of claim 27 wherein the PECVD of Ti includes forming within the chamber a first plasma of a gas mixture comprising titanium halide and hydrogen, wherein the first plasma is created within 25 mm of the substrate surface.",
    "33. The method of claim 27, wherein the plasma during nitriding is created within 25 mm of the deposited titanium film.",
    "34. The method of claim 27, wherein the temperature of the substrate surface is not more than 700° C.",
    "35. The method of claim 27 further comprising an initial step of pre-coating at least one of an internal chamber surface with TiN after cleaning the chamber surface.",
    "36. The method of claim 27, wherein the substrate surface is silicon, and further comprising during the step of depositing the titanium film forming a layer of titanium silicide between the silicon substrate surface and the deposited titanium film."
  ],
  "description_excerpt": "This application is a continuation-in-part of U.S. patent application Ser. No. 09/294,487, filed Apr. 20, 1999 now abn, hereby expressly incorporated by reference herein.\n\nThis invention relates generally to chemical vapor deposition (CVD) for applying film coatings to substrates, and more specifically to CVD for applying barrier layer stacks, of for example titanium and titanium nitride, to semiconductor wafer substrates.\n\nIn the formation of integrated circuits (IC's), thin films containing metal elements are often deposited upon the surface of a substrate, such as a semiconductor wafer. Thin films are deposited to provide conducting and ohmic contacts in the circuits and between the various devices of an IC. For example, a desired thin film might be applied to the exposed surface of a contact or via hole on a semiconductor wafer, with the film passing through the insulative layers on the wafer to provide plugs of conductive material for the purpose of making interconnections across the insulating layers.\n\nOne well known process for depositing thin metal films is chemical vapor deposition (CVD) in which a thin film is deposited using chemical reactions between various deposition or reactant gases at the surface of the substrate. In CVD, reactant gases are pumped into proximity with a substrate inside a reaction chamber, and the gases subsequently react at the substrate surface resulting in one or more reaction by-products which form a film on the substrate surface. Any by-products remaining after the deposition are removed from the chamber.",
  "cpc": [
    "H10W 20/048",
    "C23C 16/0218",
    "C23C 16/14",
    "C23C 16/34",
    "C23C 16/50",
    "C23C 16/56",
    "H10P 14/418",
    "H10P 14/43",
    "H10W 20/033"
  ],
  "ipc": [
    "C23C 16/02",
    "C23C 16/14",
    "C23C 16/30",
    "C23C 16/34",
    "C23C 16/56",
    "H10P 14/24"
  ],
  "assignees": [
    "Tokyo Electron Ltd"
  ],
  "inventors": [
    "Gerrit J. Leusink",
    "Michael G. Ward",
    "Michael S. Ameen",
    "Joseph T. Hillman"
  ],
  "filing_date": "2000-04-21",
  "publication_date": "2001-08-14",
  "grant_date": "2001-08-14",
  "priority_date": "1999-04-20",
  "application_number": "US-55383300-A",
  "family_id": "23133656",
  "cited_by_count": 394,
  "citations": [
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    "JPH06349774A",
    "WO1995033865A1",
    "US5593511A",
    "WO1996012048A2",
    "US6225213B1",
    "US5926737A"
  ]
}