Circuit board unit and method for production thereof

• US 20080160246A1
• Filed: 10/25/2007
• Published: 07/03/2008
• Est. Priority Date: 10/27/2006
• Status: Active Grant

• Current Assignee: Agie Charmilles SA (Georg Fischer AG), Charmilles Technologies SA (Georg Fischer AG)
• Original Assignee: Agie Charmilles SA (Georg Fischer AG)
• Inventors: Buhler, Ernst, D'Amario, Rino, Knaak, Reto
• Granted Patent: US 7,948,758 B2
• Time in Patent Office: Days
• US Class Current: 428/99
• CPC Class Codes: B23H 1/02 Electric circuits specially adapted therefor, e.g. power supply, control, preventing short circuits or other abnormal discharges
• CPC Class Codes: B23H 11/00 Auxiliary apparatus or details, not otherwise provided for
• CPC Class Codes: H01L 23/3735 Laminates or multilayers, e.g. direct bond copper ceramic substrates
• CPC Class Codes: H01L 23/467 by flowing gases, e.g. air H01L23/473 takes precedence
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H05K 1/0206 by printed thermal vias
• CPC Class Codes: H05K 1/0272 Adaptations for fluid transport, e.g. channels, holes
• CPC Class Codes: H05K 1/144 Stacked arrangements of planar printed circuit boards
• CPC Class Codes: H05K 2201/0187 with regions of different dielectrics in the same layer, e.g. in a printed capacitor for locally changing the dielectric properties
• CPC Class Codes: H05K 2201/043 Stacked PCBs with their backs attached to each other without electrical connection
• CPC Class Codes: H05K 2201/10166 Transistor
• CPC Class Codes: H05K 3/0061 onto a metallic substrate, e.g. a heat sink heat sinks for electric apparatus H05K7/20
• CPC Class Codes: Y10T 29/49139 by inserting component lead or terminal into base aperture
• CPC Class Codes: Y10T 428/24008 including fastener for attaching to external surface

Abstract

The invention relates to a circuit board unit and a method for production thereof. The circuit board unit comprises a circuit board topmost laminate with conductive tracks on the upper side for mounting surface-mountable devices. The circuit board topmost laminate features a thickness dimensioned such that the anticipated heat dissipated by the surface-mountable devices is transported from the upper side to the underside of the circuit board laminate to good effect. The circuit board unit further comprises an electrically insulating laminate arranged under the circuit board topmost laminate, inserts made of a material with good heat conductivity and electrical insulation embedded in the electrically insulating laminate at sites below surface-mountable devices with high heat dissipation, and a cooling plate arranged below the electrically insulating laminate and the inserts.

Claims

1. A method of producing a circuit board unit comprising the steps of:

producing a circuit board topmost laminate with conductive tracks on the upper side for mounting surface-mountable devices in a thickness dimensioned such that an estimated heat dissipated by the surface-mountable devices is transported from the upper side to the underside of the circuit board topmost laminate;

arranging under the circuit board topmost laminate an insulation laminate;

embedding in the insulation laminate at sites below surface-mountable devices with high heat dissipation, inserts made of a material with good heat conductivity and electrical insulation; and

arranging below the insulation laminate and the inserts a cooling plate.

2. The method as set forth in claim 1, wherein one or more plated-through holes for transporting the dissipated heat from the upper side to the underside of the topmost laminate at sites below surface-mountable devices with high heat dissipation are provided, the number and design of said plated-through holes being adapted to an estimated heat dissipated of each surface-mountable device, and wherein the circuit board topmost laminate is produced from a glass-fiber epoxy resin material or from a powder-filled polymer.

6. The method as set forth in claim 1, wherein the electrically insulating laminate is produced from a glass-fiber epoxy resin material or from a powder-filled polymer, and wherein the inserts are produced from a ceramic having high thermal conductivity and high electrical insulation, particularly aluminum nitride (AlN) or aluminum oxide (Al₂O₃).

10. The method as set forth in claim 1, wherein the cooling plate is produced from a metal or metal alloy having good thermal conductivity and resistance to corrosion, and cooling passageways are provided for routing a coolant through the cooling plate.

11. The method as set forth in claim 1, wherein two circuit board units are combined with additional sidewalls into a circuit board module such that the two cooling plates of the two circuit board units form outer walls of the circuit board module and together with the sidewalls a hermetically sealed package, and the two circuit board units are interconnected electrically directly by means of surface-mountable device connectors, the circuit board units being ambiently connected via hermetically sealed electrical connections through the additional sidewalls.

12. The method as set forth in claim 11, wherein a plurality of circuit board modules is combined into a system pack such that the circuit board modules located within the system pack share a cooling plate.

14. The method as set forth in claim 1, wherein the electrically insulating laminate and the inserts are releasably connected to the cooling plate and the releasable connection is produced in accordance with at least one of the following connections:

a soft-solder joint of a solder alloy with a low melting point;

a hot-melt bond which is remeltable;

a two-sided self-adhesive film which is detachable; and

via a difference in air pressure between the upper side of the circuit board topmost laminate and an air-permeable, heat conducting intermediate layer between the electrically insulating laminate and the inserts on the one hand and the cooling plate on the other hand.

15. The method as set forth in claim 14, wherein the air-permeable, heat conducting intermediate layer is made of at least one of the following materials;

a wire mesh;

a structured film; and

a fabric.

17. The method as set forth in claim 10, wherein water is used as the coolant and anti-freeze, corrosion inhibitors and/or active agents against algae and microbes are added to the water.

20. The method as set forth in claim 1, wherein the cooling plate is composed of two structured semi-boards, wherein the structures of the semi-boards are produced by at least one of the following methods:

machining;

pressing;

cutting with a further layer separation of the semi-boards;

casting; and

die-casting, and wherein the semi-boards are joined together by at least one of the following methods;

bonding;

soft-soldering;

brazing; and

welding, and wherein the structures in the heat exchanger zones are configured so that a labyrinth materializes from joining the two semi-boards together, and wherein at least two planes for conductive tracks are configured on the circuit board topmost laminate.

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25. A circuit board unit comprising:

a circuit board topmost laminate with conductive tracks on the upper side for mounting surface-mountable devices in a thickness dimensioned such that an estimated heat dissipated by the surface-mountable devices is transported from the upper side to the underside of the circuit board topmost laminate;

an electrically insulating laminate arranged under the circuit board topmost laminate;

inserts made of a material with good heat conductivity and electrical insulation embedded in the electrically insulating laminate at sites below surface-mountable devices with high heat dissipated; and

a cooling plate arranged below the electrically insulating laminate and the inserts.

26. The circuit board unit as set forth in claim 25, wherein the circuit board topmost laminate is produced from a glass-fiber epoxy resin material or from a powder-filled polymer.

28. The circuit board unit as set forth in claim 25, wherein the electrically insulating laminate is produced from a glass-fiber epoxy resin material or from a powder-filled polymer, and wherein the inserts are produced from a ceramic having high thermal conductivity and high electrical insulation, particularly aluminum nitride (AlN) or aluminum oxide (Al₂O₃).

32. The circuit board unit as set forth in claim 25, wherein the cooling plate is made from one of aluminum, an aluminum alloy, copper and a copper alloy.

35. The circuit board unit as set forth in claim 25, wherein the cooling plate is composed of two structured semi-boards.

36. The circuit board unit as set forth in claim 25, wherein the cooling plate is composed of four punched board layers.

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37. A circuit board module comprising:

two circuit board units, each including a circuit board topmost laminate with conductive tracks on the upper side for mounting surface-mountable devices in a thickness dimensioned such that an estimated heat dissipated by the surface-mountable devices is transported from the upper side to the underside of the circuit board topmost laminate;

an electrically insulating laminate arranged under the circuit board topmost laminate;

inserts made of a material with good heat conductivity and electrical insulation embedded in the electrically insulating laminate at sites below surface-mountable devices with high heat dissipated; and

a cooling plate arranged below the electrically insulating laminate and the inserts;

wherein the two circuit board units and additional sidewalls form the circuit board module, the circuit board units are directly electrically interconnected by surface-mountable device connectors and the electrical inputs and outputs are ported through the sidewalls by hermetically sealed electrical connections.

38. The circuit board module as set forth in claim 37, wherein two circuit board units share a cooling plate and the cooling plate comprises recesses for mounting surface-mountable device connectors which directly interconnect the two circuit boards arranged on both sides of the cooling plate.

39. The circuit board module as set forth in claim 37, wherein the circuit board units with the component side are arranged facing each other.

40. The circuit board module as set forth in claim 37, wherein the cooling plate is composed of two semi-boards comprising passageways and through holes for distributing a coolant, and wherein the semi-boards further comprise additional Passageways and through holes for exhausting air and for communicating compressed air.

44. The circuit board module as set forth in claim 37, wherein one circuit board unit is designed for control functions and the other circuit board unit for power functions.

46. The circuit board module as set forth in claim 44, wherein the circuit board unit for control functions and/or for power functions is releasably connected to the cooling plate, and the releasably connection is composed of at least one of the following:

a soft-solder joint of a solder alloy with a low melting point;

a hot-melt bond;

a two-sided self-adhesive film; and

an air-permeable, heat conducting layer between circuit board and cooling plate, this layer being subjected to a lower air pressure than that of the remaining interior space of the circuit board module in all, and wherein the air-permeable and heat conducting layer is connected by a first tubular connection, in a dry and clean environment, to atmospheric or low pressure and all of the remaining interior space of the circuit board module is supplied by a second tubular connection with dry and clean air at an elevated air pressure.

49. The circuit board module as set forth in claim 37, wherein the circuit boards comprise voltage, current, temperature, moisture, strain and/or pressure sensors and actuators for controlling the coolant flow as well as a controller for open and closed loop control, monitoring and protection of the circuit board units.

50. The circuit board module as set forth in claim 49, wherein the controller is configured such that the flow of air supplied to the circuit board module is monitored, from which information is derived for diagnostic, warning and protection functions as to the condition of the hermetic seal of the circuit board module.

51. The circuit board module as set forth in claim 37, wherein each cooling plate of the two circuit board units is configured as a metal plate and fixedly connected to each electrically insulating laminate and interconnected via an interposed molding, wherein the molding likewise forms the sidewalls, the coolant ports and/or air ports and wherein the molding is configured so that it comprises in the heat exchanger zones a labyrinth structure for the coolant flow.

54. The circuit board module as set forth in claim 51, wherein the molding is made of one of a plastics material, a metallized plastics material, a metal and a metal alloy.

55. A system pack including at least two circuit board modules as set forth in claim 37, wherein the at least two circuit board modules are stacked to form a system pack.

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