Vault-shaped target and magnetron having both distributed and localized magnets

{
  "publication_number": "US6436251B2",
  "country": "US",
  "kind": "B2",
  "title": "Vault-shaped target and magnetron having both distributed and localized magnets",
  "abstract": "A target and magnetron for a plasma sputter reactor. The target has an annular vault facing the wafer to be sputter coated. Preferably, the magnetron includes annular magnets of opposed polarities disposed behind the two vault sidewalls and a small closed unbalanced magnetron of nested magnets of opposed polarities scanned along the vault roof. The nested magnets are rotated along the vault. An integrated copper via filling process with the inventive reactor or other reactor includes a first step of highly ionized sputter deposition of copper, which can optionally be used to remove the barrier layer at the bottom of the via, a second step of more neutral, lower-energy sputter deposition of copper to complete the seed layer, and a third step of electroplating copper into the hole to complete the metallization. The first two steps can be also used with barrier metals.",
  "claims": [
    "1. A magnetron plasma sputter reactor, comprising: a plasma chamber arranged about a central axis and configured to accommodate a substrate to be sputter coated; a target arranged around said central axis and having at least one annular vault disposed on a first side of said target facing said substrate, said vault having an inner sidewall, an outer sidewall, and a roof, said target being configured to receive electrical power to create a plasma within said plasma chamber; a first magnetron system producing a first magnetic field distribution that is substantially uniform along a circumference of said vault about said central axis, wherein said first magnetron system comprises: at least one first magnet disposed behind said inner sidewall; and second magnets disposed behind said outer sidewall; and a second magnetron system producing at any one time a second magnetic field distribution in a localized area along said circumference of said vault and being rotatable along said circumference.",
    "2. The reactor of claim 1, wherein said at least one first magnet has a first magnetic polarity along said central axis and said second magnets have a second magnetic polarity along said central axis opposite said first magnetic polarity.",
    "3. The reactor of claim 2, wherein said second magnetron system is disposed behind said roof and comprises: at least one third magnet of a third magnetic polarity along said central axis and producing a first total magnetic flux; and at least one fourth magnet of a fourth magnetic polarity along said central axis opposite said third magnetic polarity, surrounding said at least one third magnet, and producing a second total magnetic flux.",
    "4. The reactor of claim 3, wherein said second total magnetic flux is at least 50% greater than said first total magnetic flux.",
    "5. The magnetron of claim 1, wherein said at least one first magnet includes two first magnets arranged along said central axis and separated by a non-magnetic spacer.",
    "6. A magnetron plasma sputter reactor, comprising: a plasma chamber arranged about a central axis and configured to accommodate a substrate to be sputter coated; a target arranged around said central axis and having at least one annular vault disposed on a first side of said target facing said substrate, said vault having an inner sidewall, an outer sidewall, and a roof, said target being configured to receive electrical power to create a plasma within said plasma chamber; a first magnetron system producing a first magnetic field distribution that is substantially uniform along a circumference of said vault about said central axis; and a second magnetron system producing at any one time a second magnetic field distribution in a localized area along said circumference of said vault and being rotatable along said circumference disposed behind said roof, wherein said second magnetron system comprises at least one first magnet of a first magnetic polarity along said central axis and producing a first total magnetic flux; and at least one second magnet of a second magnetic polarity along said central axis opposite said first magnetic polarity, surrounding said at least one first magnet, and producing a second total magnetic flux.",
    "7. The reactor of claim 6, wherein said second total magnetic flux is at least 50% greater than said first total magnetic flux.",
    "8. A magnetron for use with a vaulted target having an annular vault arranged about a central axis, having an inner sidewall, an outer sidewall, and a roof, said magnetron system comprising: a yoke rotatable about said central axis; a first magnet assembly of a first magnetic polarity supported on said yoke and disposable in back of said inner sidewall of said vault; a second magnet assembly of a second magnetic polarity opposite said first magnetic polarity disposable in back of said outer sidewall of said vault; a third magnet assembly of said first magnetic polarity supported on said magnetic yoke and disposable in back of said roof of said vault and producing a first total magnetic flux; and a fourth magnet assembly of said second magnetic polarity supported on said magnetic yoke, surrounding said third magnet assembly and disposable in back of said roof of said vault and producing a second total magnetic flux.",
    "9. The magnetron of claim 8, wherein said second total magnetic flux is at least 1.5 times said first total magnetic flux.",
    "10. The magnetron of claim 8, wherein said second magnet assembly extends completely around said central axis.",
    "11. The magnetron of claim 10, wherein said second magnet assembly is stationary.",
    "12. A magnetron plasma sputter reactor, comprising: a plasma chamber arranged about a central axis and configured to accommodate a substrate to be sputter coated; a target arranged around said central axis and having at least one annular vault disposed on a first side of said target facing said substrate, said vault having an inner sidewall, an outer sidewall, and a roof, said target being configured to receive electrical power to create a plasma within said plasma chamber; a first magnetron system producing a first magnetic field distribution that is substantially uniform along a circumference of said vault about said central axis; and a second magnetron system positioned in back of said roof and producing at any one time a second magnetic field distribution in a localized area along said circumference of said vault and being rotatable along said circumference.",
    "13. The reactor of claim 12, wherein said first magnetron system includes: at least one first magnet of a first magnetic polarity along said central axis disposed behind said inner sidewall; and second magnets of a second magnetic polarity opposite said first magnetic polarity disposed behind said outer sidewall."
  ],
  "description_excerpt": "The invention relates generally to plasma sputtering. In particular, the invention relates to the sputter target and associated magnetron used in a sputter reactor and to an integrated via filling process using sputtering.\n\nA semiconductor integrated circuit contains many layers of different materials usually classified according to whether the layer is a semiconductor, a dielectric (electrical insulator) or metal. However, some materials such as barrier materials, for example, TiN, are not so easily classified. The two principal current means of depositing metals and barrier materials are sputtering, also referred to as physical vapor deposition (PVD), and chemical vapor deposition (CVD). Of the two, sputtering has the inherent advantages of low cost source material and high deposition rates. However, sputtering has an inherent disadvantage when a material needs to be filled into a deep narrow hole, that is, one having a high aspect ratio. The same disadvantage obtains when a thin layer of the material needs be coated onto the sides of the hole, which is often required for barrier materials. Aspect ratios of 3:1 present challenges, 5:1 becomes difficult, 8:1 is becoming a requirement, and 10:1 and greater are expected in the future. Sputtering itself is fundamentally a nearly isotropic process producing ballistic sputter particles which do not easily reach the bottom of deep narrow holes. On the other hand, CVD tends to be a conformal process equally effective at the bottom of holes and on exposed top planar surfaces.",
  "cpc": [
    "H10W 20/034",
    "C23C 14/046",
    "C23C 14/165",
    "C23C 14/185",
    "C23C 14/225",
    "C23C 14/35",
    "C23C 14/352",
    "H01J 37/3405",
    "H01J 37/342",
    "H01J 37/3423",
    "H01J 37/3452",
    "H01J 37/3455",
    "H01J 37/3458",
    "H10P 14/44",
    "H10W 20/033",
    "H10W 20/0425",
    "H10W 20/043",
    "H10W 20/0523",
    "H10W 20/054",
    "H10W 20/083"
  ],
  "ipc": [
    "C23C 14/04",
    "C23C 14/16",
    "C23C 14/32",
    "C23C 14/34",
    "C23C 14/35",
    "H01J 37/34",
    "H10P 14/22"
  ],
  "assignees": [
    "Applied Materials Inc"
  ],
  "inventors": [
    "Praburam Gopalraja",
    "Jianming Fu",
    "Wei Wang"
  ],
  "filing_date": "2001-05-11",
  "publication_date": "2002-08-20",
  "grant_date": "2002-08-20",
  "priority_date": "2000-01-21",
  "application_number": "US-85428101-A",
  "family_id": "27413858",
  "cited_by_count": 89,
  "citations": [
    "US4746417A",
    "JPH024966A",
    "US5178739A",
    "JPH059722A",
    "US5482611A",
    "US5865961A",
    "US5512150A",
    "US5589041A",
    "US5685959A",
    "US6080284A",
    "US5985762A",
    "US6156172A",
    "JPH11106914A",
    "US6217716B1",
    "US6193854B1",
    "US6179973B1",
    "WO2000048226A1",
    "US6251242B1",
    "US6277249B1"
  ]
}