Flexible power assembly

• US 6,362,964 B1
• Filed: 11/09/2000
• Issued: 03/26/2002
• Est. Priority Date: 11/17/1999
• Status: Expired due to Fees

• Current Assignee: ASBU Holdings, LLC
• Original Assignee: International Rectifier Corporation (Infineon Technologies AG)
• Inventors: Vaysse, Bertrand P., Lin, Heny W., Corfield, Michael A., Siu, Stephen Nicholas, Dubhashi, Ajit
• Primary Examiner(s): TOLIN, GERALD P
• Application Number:
  US09/709,883
• Time in Patent Office: 502 Days
• Field of Search: 361/816, 361/818, 361/761, 361/764, 361/704, 361/705, 361/707, 361/713, 361/709-711, 361/717-719, 174/35.R, 174/52.3, 165/80.3, 165/185, 257/698, 257/704, 257/706, 257/712, 257/713, 257/723, 257/724
• US Class Current: 361/707
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/0603 Bonding areas having different sizes, e.g. different heights or widths
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/48139 with an intermediate bond, e.g. continuous wire daisy chain
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/85399 Material
• CPC Class Codes: H01L 23/24 solid or gel at the normal operating temperature of the device H01L23/3135 takes precedence
• CPC Class Codes: H01L 23/4006 with bolts or screws
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/49 of a plurality of wire connectors
• CPC Class Codes: H01L 24/73 Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• CPC Class Codes: H01L 25/16 the devices being of types provided for in two or more different main groups of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. forming hybrid circuits
• CPC Class Codes: H01L 25/162 the devices being mounted on two or more different substrates
• CPC Class Codes: H01L 25/165 : Containers
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01057 : Lanthanum [La]
• CPC Class Codes: H01L 2924/01068 : Erbium [Er]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/12041 : LED
• CPC Class Codes: H01L 2924/13055 : Insulated gate bipolar transistor [IGBT]
• CPC Class Codes: H01L 2924/15153 : the die mounting substrate comprising a recess for hosting the device
• CPC Class Codes: H01L 2924/1517 : Multilayer substrate
• CPC Class Codes: H01L 2924/16152 : Cap comprising a cavity for hosting the device, e.g. U-shaped cap
• CPC Class Codes: H01L 2924/16195 : Flat cap [not enclosing an internal cavity]
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/19041 : being a capacitor
• CPC Class Codes: H01L 2924/19105 : in a side-by-side arrangement on a common die mounting substrate
• CPC Class Codes: H01L 2924/207 : Diameter ranges
• CPC Class Codes: H01L 2924/30107 : Inductance
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding
• CPC Class Codes: H05K 7/1432 : specially adapted for power drive units or power converters
• CPC Class Codes: H05K 7/14322 : wherein the control and power circuits of a power converter are arranged within the same casing
• CPC Class Codes: H05K 7/209 : Heat transfer by conduction from internal heat source to heat radiating structure H05K7/20909 takes precedence

Abstract

A flexible power assembly (FPA) provides a new packaging concept suitable for motor control and other functions. An insulated metal substrate (IMS) supports power semiconductor devices and is mounted directly on a heatsink, which supports a circuit board that is mounted above and spaced from the top side of the IMS. There are provided devices that are mounted on the circuit board which are electrically connected to the power semiconductor devices. There may be a cavity in the circuit board allowing the top of the IMS to be exposed, and optionally providing access for bonding wires to the top of the circuit. Bonding pads may be provided on the circuit board for electrical connection with the bonding wires. A cover may be optionally provided to enclose a space over the cavity. Potting compound may be contained in the space created by the cavity.

Claims

1. A semiconductor device module comprising:

a heatsink having a top surface and a bottom surface;

a planar, thermally conductive substrate having a top surface including a surface area and a bottom surface thermally connected to said top surface of said heatsink;

at least one semiconductor device mounted on said top surface of said thermally conductive substrate;

at least one circuit board, having a bottom surface and a top surface, arranged above and spaced from said top surface of said thermally conductive substrate, said circuit board having an opening therein that is situated above said thermally conductive substrate, said opening having an opening area, wherein said at least one semiconductor device on said conductive substrate is exposed through said opening; and

at least another device mounted on said circuit board, said another device being electrically connected to said semiconductor device on said thermally conductive substrate;

wherein said circuit board is directly mounted on said heatsink.

2. The semiconductor device module of claim 1, wherein said thermally conductive substrate has an outer rim and wherein said outer rim of said top surface of said thermally conductive substrate is adhesively attached to said bottom surface of said circuit board thereby closing said opening.

3. The semiconductor device module of claim 1, wherein said thermally conductive substrate has an outer rim and wherein said outer rim of said top surface of said thermally conductive substrate is adhesively attached to said bottom surface of said circuit board by adhesive tape.

4. The semiconductor device module of claim 1, wherein said at least one semiconductor device is electrically connected to said another device by a bonding wire.

5. The semiconductor device module of claim 1, further comprising at least one bonding pad disposed along the periphery of said opening and electrically connected to said semiconductor device by a bonding wire.

6. The semiconductor device module of claim 1, further comprising a molded cover disposed on said top surface of said circuit board enclosing a space above said opening in said circuit board.

7. The semiconductor device module of claim 6, wherein said space enclosed by said molded cover contains potting material.

8. The semiconductor device module of claim 1, wherein said circuit board is directly supported on said heatsink by at least one standoff and mounted on said heatsink by a screw.

9. The semiconductor device module of claim 1, wherein said thermally conductive substrate is an insulated metal substrate.

10. The semiconductor device module of claim 1, wherein a portion of said top surface of said heatsink is raised to provide a platform under said bottom surface of said thermally conductive substrate.

11. The semiconductor device module of claim 10, wherein said surface area of said top surface of said thermally conductive substrate is smaller than said opening thereby allowing said substrate to fit through said opening, further comprising insulation means tucked between a rim around said opening on said bottom surface of said circuit board and said top surface of said platform on said heatsink.

12. The semiconductor device module of claim 11, further comprising a molded cover disposed on said top surface of said circuit board to enclose a space over said opening in said circuit board.

13. The semiconductor device module of claim 12, wherein said space enclosed by said molded cover contains potting material.

14. The semiconductor device module of claim 11, wherein said surface area of said top surface of said thermally conductive substrate is larger than said opening area, thereby preventing said substrate from fitting through said opening, further comprising at least one electrical contact on said top surface of said thermally conductive substrate electrically connected to said semiconductor device by at least one bonding wire, said at least one electrical contact electrically touching at least another electrical contact disposed on said bottom surface of said circuit board, said another contact being electrically connected to said at least another device on said circuit board.

15. The semiconductor device module of claim 14, wherein said opening in said circuit board is closed by said thermally conductive substrate.

16. The semiconductor device module of claim 15, further comprising a molded cover disposed on said top surface of said circuit board, said molding cover enclosing a space over said opening in said circuit board.

17. The semiconductor device module of claim 16, wherein said space contains potting material.

18. A semiconductor device module comprising:

a heatsink having a top surface and a bottom surface;

a planar, thermally conductive substrate having a top surface and a bottom surface thermally connected to said top surface of said heatsink;

at least one semiconductor device mounted on said top surface of said thermally conductive substrate;

at least one circuit board, having a bottom surface and a top surface, arranged above and spaced from said top surface of said thermally conductive substrate;

an enclosure means disposed between said top surface of said thermally conductive substrate and said bottom surface of said circuit board to define a space between said thermally conductive substrate and said bottom of said circuit board;

at least one via for providing electrical communication from said semiconductor device to said top of said circuit board;

at least one bonding wire electrically connecting said semiconductor device to said via;

at least another device mounted on said top surface of said circuit board and electrically connected to said via.

19. The semiconductor device module of claim 18, wherein said circuit board is mounted on said top surface of said heatsink.

20. The semiconductor device module of claim 19, wherein said circuit board is supported on said top surface of said heatsink by at least one circuit board standoff and mounted on said heatsink by at least one screw.

21. The semiconductor device module of claim 18, wherein the space between said thermally conductive substrate and said bottom of said circuit board contains a potting material.

22. The semiconductor device module of claim 21, wherein said potting material is a gel.

23. The semiconductor device module of claim 18, wherein said thermally conductive substrate is an insulated metal substrate.

24. An improved semiconductor device module of the type made from the combination of a support base having top and bottom surfaces and having an opening therein which extends from said top surface to said bottom surface, a length and a width of said support base defining a first area;

a planar, thermally conductive substrate disposed in said opening in said support base such that a bottom surface of said substrate is disposed to contact an external heatsink located beneath said bottom surface of said support base, a length and a width of said planar, thermally conductive substrate defining a second area such that said first area is at least approximately six times larger than said second area;

at least one semiconductor device mounted on a top surface of said thermally conductive substrate;

at least one circuit board arranged above and spaced from said top surface of said base and having an opening therein that is situated above said thermally conductive substrate;

at least another device mounted on a top surface of said circuit board;

said top surface of said circuit board having at least one bonding pad area arranged at a periphery of said opening in said circuit board and being electrically connected to said another device;

at least one bonding wire for connecting said one semiconductor device to said bonding pad; and

a cover, having a planar top face, situated above said circuit board and said thermally conductive substrate wherein the improvement comprises;

application of a conductive shielding material to said cover to reduce the allowance of radiated RFI noise from said at least one bonding wires.

25. The improved semiconductor device module of claim 24, wherein said cover is made from said conductive shielding material.

26. The improved semiconductor device module of claim 24, wherein said cover provides support to at least one capacitor.

27. The improved semiconductor device module of claim 26, wherein a first capacitor and a second capacitor, each being cylindrically shaped and each having a side, are supported on their said respective sides on a first plane and a second plane respectively above said cover by means of a support structure, said support structure comprising, a first stop member restricting the lateral movement of said first capacitor to prevent the same from falling over said top of said cover;

a second stop member restricting the lateral movement of said second capacitor, said second stop member integrally attached to a support means to vertically support said second capacitor on a plane above said top of said first plate, said stop member preventing said second capacitor from falling over said top of said cover;

said first stop member, said second stop member, and said support means being integrally formed on said top of said cover.

28. The improved semiconductor device module of claim 24 or 25, wherein a potting material is contained within a space created by said molded cover and said circuit board.

29. The improved semiconductor device module according to claim 28, wherein said potting material is a gel.

30. The improved semiconductor device of claim 24, wherein said thermally conductive substrate is an insulated metal substrate.