Group III nitride based flip-chip intergrated circuit and method for fabricating

{
  "publication_number": "US6825559B2",
  "country": "US",
  "kind": "B2",
  "title": "Group III nitride based flip-chip intergrated circuit and method for fabricating",
  "abstract": "A flip-chip integrated circuit includes a circuit substrate having electronic components. The circuit substrate typically includes GaAs or Si. Another substrate can include Group III nitride based active semiconductor devices. This substrate typically includes SiC and can be separated to provide individual nitride devices. After separation, one or more of the Group III devices can be flip-chip mounted onto the circuit substrate. The electronic components on the circuit substrate can be coupled to the nitride devices using conductive interconnects and/or vias.",
  "claims": [
    "1. A flip-chip integrated circuit, comprising: a circuit substrate having drive electronics on one surface; an active semiconductor device comprising a substrate with layers of semiconductor material and a plurality of terminals, each of said terminals in electrical contact with one of said layers of semiconductor material, said active semiconductor device flip-chip mounted on said circuit substrate, at least one of said terminals in electrical contact with said drive electronics; and at least one conductive vias through said circuit substrate, each of said conductive vias in electrical contact with one of said plurality of terminals.",
    "2. The integrated circuit of claim 1, wherein each of said at least one vias comprises a hole through said circuit substrate, the surface of said hole covered by a first layer of conductive material.",
    "3. The integrated circuit of claim 2, further comprising a second layer of conductive material on the surface of said circuit substrate opposite said drive electronics.",
    "4. The integrated circuit of claim 3, wherein said second layer of conductive material is in electrical and thermal contact with said first layer of conductive material, said second layer of conductive material forming a ground for said vias and dissipating heat from said active semiconductor device.",
    "5. The integrated circuit of claim 1, further comprising at least one heat sink base plate to help dissipate heat from said active semiconductor device and drive electronics.",
    "6. The integrated circuit of claim 5, wherein said at least one heat sink base plate comprises a heat sink base plate arranged adjacent to said substrate.",
    "7. The integrated circuit of claim 1, wherein each of said at least one vias further comprises a plug of conductive material at the top of said via.",
    "8. The integrated circuit of claim 1, wherein said drive electronics comprise passive components and interconnects.",
    "9. The integrated circuit of claim 1, wherein said drive electronics comprise pre-stage amplifiers and interconnects.",
    "10. The integrated circuit of claim 7, further comprising a conductive bonding pad between each of said at least one terminal and vias that are in electrical contact.",
    "11. A flip-chip integrated circuit, comprising: a circuit substrate having drive electronics on one surface; an active semiconductor device comprising a substrate with layers of semiconductor material and a plurality of terminals, each of said terminals in electrical contact with one of said layers of semiconductor material, said active semiconductor device flip-chip mounted on said circuit substrate, at least one of said terminals in electrical contact with said drive electronics; a second layer of conductive material on the surface of said circuit substrate opposite said drive electronics; and at least one heat sink base plate to help dissipate heat from said active semiconductor device and drive electronics, wherein said at least one heat sink base plate comprises a heat sink base plate arranged adjacent to said second conductive layer.",
    "12. The integrated circuit of claim 11, wherein said layers of semiconductor material are Group III nitride based materials and said substrate is sapphire or silicon carbide.",
    "13. A flip-chip integrated circuit, comprising: a high electron mobility transistor (HEMT) comprising; a substrate; a high resistivity semiconductor layer on said substrate; a barrier semiconductor layer on said high resistivity layer, said barrier layer having a wider bandgap than said high resistivity layer; a two-dimensional electron gas between said barrier layer and said high resistivity layer; respective source and drain contacts on said high resistivity layer and contacting said barrier layer; a gate contact on said barrier semiconductor layer; and a circuit substrate comprising drive electronics on one surface and a conductive vias, said HEMT flip-chip mounted on said circuit substrate with said source contact in electrical contact with said conductive vias, and said gate and drain contacts in electrical contact with said drive electronics.",
    "14. The integrated circuit of claim 13, wherein said high resistivity semiconductor layer and said barrier semiconductor layer are made of a Group III nitride semiconductor material.",
    "15. The integrated circuit of claim 13, wherein said substrate is made of a material from the group consisting of sapphire and silicon carbide.",
    "16. The integrated circuit of claim 13, further comprising a layer of conductive material on the surface of said circuit substrate opposite said passive components, said layer of conductive material in electric and thermal contact with said vias.",
    "17. The integrated circuit of claim 13, further comprising one or more heat sink base plates to dissipate heat from said HEMT and said passive components.",
    "18. The integrated circuit of claim 13, wherein said drive electronics comprise pre-stage amplifiers and integrated circuits."
  ],
  "description_excerpt": "1. Field of the Invention\n\nThis invention relates to nitride based semiconductor devices, and more particularly to nitride based power devices that are flip-chip mounted on circuit substrates having passive components and/or pre-stage amplifiers.\n\n2. Description of the Related Art\n\nMicrowave systems commonly use solid state transistors as amplifiers and oscillators, which has resulted in significantly reduced system size and increased reliability. To accommodate the expanding number of microwave systems, there is an interest in increasing their operating frequency and power. Higher frequency signals can carry more information (bandwidth), allow for smaller antennas with very high gain, and provide radar with improved resolution.\n\nField effect transistors (FETs) and high electron mobility transistors (HEMTs) are common solid state transistors that can be fabricated from semiconductor materials such as Silicon (Si) or Gallium Arsenide (GaAs). One disadvantage of Si is that it has low electron mobility (approximately 1450 cm 2 /V-s), which produces a high source resistance. This resistance seriously degrades the high performance gain otherwise possible from Si based HEMTs. [CRC Press, The Electrical Engineering Handbook, Second Edition, Dorf, p.994, (1997)]\n\nGaAs is also a common material for use in HEMTs and has become the standard for signal amplification in civil and military radar, handset cellular, and satellite communications. GaAs has a higher electron mobility (approximately 6000 cm 2 /V-s) and a lower source resistance than Si, which allows GaAs based devices to function at higher frequencies.",
  "cpc": [
    "H10D 84/05",
    "H05K 1/0206",
    "H05K 1/181",
    "H05K 2201/066",
    "H10D 30/4755",
    "H10D 62/8503",
    "H10D 84/01",
    "H10D 84/0123",
    "H10W 40/22",
    "H10W 40/228",
    "H10W 44/20",
    "H10W 70/698",
    "H10W 72/07252",
    "H10W 72/227",
    "H10W 72/877",
    "H10W 90/724",
    "Y10T 29/4913"
  ],
  "ipc": [
    "H01L 23/66",
    "H10D 30/01",
    "H10D 30/87",
    "H10D 84/05",
    "H10D 84/40",
    "H10D 99/00"
  ],
  "assignees": [
    "Cree Inc"
  ],
  "inventors": [
    "Umesh K. Mishra",
    "Primit Parikh",
    "Yifeng Wu"
  ],
  "filing_date": "2003-01-02",
  "publication_date": "2004-11-30",
  "grant_date": "2004-11-30",
  "priority_date": "2003-01-02",
  "application_number": "US-33591503-A",
  "family_id": "32680887",
  "cited_by_count": 69,
  "citations": [
    "GB2136203A",
    "US5192987A",
    "US5949140A",
    "EP0938139A2"
  ]
}