GB2345576A - Heat-sink of ICs and method of mounting to PCBs - Google Patents

Heat-sink of ICs and method of mounting to PCBs Download PDF

Info

Publication number
GB2345576A
GB2345576A GB9900165A GB9900165A GB2345576A GB 2345576 A GB2345576 A GB 2345576A GB 9900165 A GB9900165 A GB 9900165A GB 9900165 A GB9900165 A GB 9900165A GB 2345576 A GB2345576 A GB 2345576A
Authority
GB
United Kingdom
Prior art keywords
heat sink
board
heat
printed circuit
generating component
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB9900165A
Other versions
GB9900165D0 (en
Inventor
Carl Carley
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Telefonaktiebolaget LM Ericsson AB filed Critical Telefonaktiebolaget LM Ericsson AB
Priority to GB9900165A priority Critical patent/GB2345576A/en
Publication of GB9900165D0 publication Critical patent/GB9900165D0/en
Publication of GB2345576A publication Critical patent/GB2345576A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/0201—Thermal arrangements, e.g. for cooling, heating or preventing overheating
    • H05K1/0203—Cooling of mounted components
    • H05K1/0204—Cooling of mounted components using means for thermal conduction connection in the thickness direction of the substrate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
    • H01L23/367—Cooling facilitated by shape of device
    • H01L23/3677—Wire-like or pin-like cooling fins or heat sinks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/0001—Technical content checked by a classifier
    • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09—Shape and layout
    • H05K2201/09209—Shape and layout details of conductors
    • H05K2201/09654—Shape and layout details of conductors covering at least two types of conductors provided for in H05K2201/09218 - H05K2201/095
    • H05K2201/09781—Dummy conductors, i.e. not used for normal transport of current; Dummy electrodes of components
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
    • H05K2201/10227—Other objects, e.g. metallic pieces
    • H05K2201/10416—Metallic blocks or heatsinks completely inserted in a PCB
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
    • H05K2201/10613—Details of electrical connections of non-printed components, e.g. special leads
    • H05K2201/10621—Components characterised by their electrical contacts
    • H05K2201/10689—Leaded Integrated Circuit [IC] package, e.g. dual-in-line [DIL]
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
    • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
    • H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
    • H05K3/341—Surface mounted components

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Power Engineering (AREA)
  • Cooling Or The Like Of Electrical Apparatus (AREA)
  • Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)

Abstract

A heat-sink suitable for use with ICs is of a generally cylindrical cross-section with one end region of larger cross-section. A method of mounting such a heat-sink 14 to a heat generating component 26 and a PCB 2 consists of the following steps: the heat-sink 14 is inserted in a slot 4 in a PCB 2 from a first PCB face 8 and held by solder 12 applied to copper foil 10 on face 8. The heat generating component 26 is then mounted to the heat-sink 14 using solder 24. Pins 28 from the component 26 are fixed with solder 20 to copper foil 22 on a second face 6 of the PCB. The heat generating component may be a power amplifier IC chip. The method may be used with pick-and place automated PCB mounting technology.

Description

HEAT SINK TECHNICAL FIELD OF THE INVENTION This invention relates to a heat sink, and in particular to a heat sink for use in an electronic circuit. In another aspect, the invention relates to a method of mounting a heat sink to a printed circuit board.
BACKGROUND OF THE INVENTION A problem which arises in many electronic devices relates to the dissipation of heat generated by the components of the device. In particular, power amplifier integrated circuits generate significant amounts of heat, which must be dissipated if they, and the surrounding components, are to be maintained at optimum operating temperatures.
A typical way of dealing with this problem involves the provision of a heat sink, which can be mounted to a printed circuit board, or other substrate, in thermal contact with the heat-generating component.
EP-A-0660399 discloses a device in which the heat sink is, for example, in the form of a slug of copper or other metal, which is located in an opening in the printed circuit board.
A further problem which arises in the manufacture of electronic circuits is that automated assembly techniques require that components should be able to be mounted easily and securely to circuit boards.
In the case of heat sinks which are mounted entirely within the printed circuit board, this mounting conventionally occurs as a pre-assembly stage, before components are mounted to the board.
SUMMARY OF THE INVENTION The present invention seeks to provide a heat sink which can be mounted to a printed circuit board by automated assembly techniques. The invention further seeks to provide a method of mounting a heat sink, and a heat generating component, to a printed circuit board, in such a way that this can form part of an automated assembly process.
According to a first aspect of the invention, there is provided a heat sink in the form of a generally cylindrical slug of thermally conductive material, having first and second ends. At one end of the slug of material, the heat sink extends beyond the periphery of the cylinder.
This has the advantage that, when mounting the heat sink to a printed circuit board, having a cylindrical hole therethrough for mounting the heat sink, solder can be placed around the outside of the hole on an upper surface of the printed circuit board, and the extension part of the heat sink can be placed on the layer of solder.
According to a second aspect of the invention, there is provided a method of mounting a heat sink, and a heat generating component, to a printed circuit board. The method comprises forming a slot through the printed circuit board, and applying solder around the outside of the slot on a first surface of the board.
The heat sink is then placed in the slot with a first end generally at a second surface of the board, and passed through a heating stage to secure the heat sink to the board. Solder is then applied to the first end of the heat sink. The heat generating component is then placed on the first end of the heat sink, and the assembly is passed through the heating stage again, to secure the component to the heat sink, and hence to the board.
This has the avantage that the mounting of the heat sink can take place during a step of a fully automated assembly process.
Preferably, when solder is applied to the first end of the heat sink, it is also applied, as required, to the second surface of the board, and the component is wire bonded to the board.
In a particularly preferred embodiment, the heat generating component is a power amplifier integrated circuit.
BRIEF DESCRIPTION OF DRAWING Figure 1 is a cross-sectional view through a printed circuit board, having a heat sink mounted thereto in accordance with the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT A printed circuit board, having a heat sink mounted thereon as shown in Figure 1, will now be described with reference to a preferred method of manufacture thereof.
A printed circuit board 2, shown in Figure 1 in partial cross-section, has a slot 4 provided therein, at a location at which a heat generating component, in this illustrative case an integrated circuit power amplifier, is to be mounted. The size of the heat sink required to conduct heat from the power amplifier can be determined with reference to the characteristics of the power amplifier, and the intended use thereof. The slot 4 can then be sized appropriately to receive the heat sink.
In the drawing, the surface 6 of the printed circuit board, to which most of the circuit components are to be mounted, is shown as the upper surface, while the other surface 8 is shown as the lower surface.
However, it will be appreciated that any orientation of the board is possible, and in particular that different orientations might be more convenient at different stages in the assembly process.
Located around the slot 4 on the lower surface 8 of the printed circuit board 2 is a layer of copper foil 10. As part of the automated assembly process of the device, that is at the same time as other components are being assembled, a layer of solder paste 12 is applied to the copper foil 10. Then the heat sink 14 is automatically located ("pick-and-placed") in the slot 4.
The heat sink 14 is in this case in the form of a slug of metal, preferably copper, which is generally cylindrical (for example circularly cylindrical, but of any convenient cross-sectional shape) for most of its length. The slot 4 is sized so that this cylindrical part 16 of the heat sink is located within the slot, although it extends beyond both surfaces of the printed circuit board 2.
In one embodiment of the invention, the heat sink 14 and slot 4 may be sized so that the heat sink is press-fitted into the slot, and stitch vias could be used around the inner surface of the slot to conduct heat to the ground plane of the board 2.
At one end region, the heat sink 14 is provided with a region 18 of increased cross-sectional area.
For example, if the cylindrical part 16 of the heat sink is circularly cylindrical, the region 18 may have a circular cross-section of larger diameter.
The outer part of the region 18 of larger crosssectional area contacts the layer 10 of copper foil.
Then, the board is passed through an oven in a conventional way, to melt the solder 12 and then allow it to resolidify, thereby securing the heat sink 14 to the board 2.
A layer of solder paste 20 is then applied to copper foil 22 surrounding the slot 4 on the upper surface 6 of the printed circuit board 2.
Further, a layer of solder paste 24 is applied to the upper surface of the heat sink 14.
Then, in the same manner as the heat sink, the power amplifier 26 is automatically located ("pick-and placed") on top of the heat sink 14, with the pins 28 of the integrated circuit in contact with the solder paste 20 on the copper foil 22. Again, this step can take place in the same stage in which other components are being located on the board.
Then, as before, the board is passed through the oven in a conventional way, to melt the solder 20,24 and then allow it to resolidify, thereby securing the power amplifier 26 to the heat sink 14, and the pins thereof to the copper foil 22.
The heat sink and power amplifier are therefore mounted securely and reliably as part of an automated process.

Claims (7)

1. A heat sink, having a generally cylindrical cross-section over most of its length, and one end region of larger cross-section.
2. A heat sink as claimed in claim 1, formed of thermally conductive material.
3. A heat sink as claimed in claim 1, having a generally circularly cylindrical cross-section of a first diameter over most of its length, and a generally circularly cylindrical cross-section of a second diameter greater than the first at the one end region.
4. A method of mounting a heat sink, and a heat generating component, to a printed circuit board, the method comprising: forming a slot through the printed circuit board; applying solder around the outside of the slot on a first surface of the board; placing the heat sink in the slot with a first end generally at a second surface of the board, the heat sink having a second end region of larger crosssectional area than the first end, and the second end region being in contact with the solder on the first surface of the board; passing the board through a heating stage to secure the heat sink to the board ; applying solder to the first end of the heat sink; placing the heat generating component on the first end of the heat sink; and passing the board through the heating stage again, to secure the component to the heat sink, and hence to the board.
5. A method as claimed in claim 4, wherein, when solder is applied to the first end of the heat sink, it is also applied to the second surface of the board, and the component is bonded to the board.
6. A method as claimed in claim 4, wherein the heat generating component is a power amplifier integrated circuit.
7. A method of assembly of an electronic device, the device including a heat generating component and a heat sink element, both mounted to a printed circuit board, wherein the printed circuit board has a hole therethrough; wherein the heat sink element is sized to fit generally within said hole, and has two end regions, a first end region at which the heat sink element has an end surface, and a second end region opposite the first, at which the heat sink element has a larger cross-sectional area; the method comprising: mounting the heat sink element in said hole in said printed circuit board, and soldering said end region of the heat sink element to one side of the printed circuit board around said hole; soldering the heat generating component to an opposite end of said heat sink element; and bonding the heat generating component to the printed circuit on a second side of said board opposite the first.
GB9900165A 1999-01-05 1999-01-05 Heat-sink of ICs and method of mounting to PCBs Withdrawn GB2345576A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9900165A GB2345576A (en) 1999-01-05 1999-01-05 Heat-sink of ICs and method of mounting to PCBs

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9900165A GB2345576A (en) 1999-01-05 1999-01-05 Heat-sink of ICs and method of mounting to PCBs

Publications (2)

Publication Number Publication Date
GB9900165D0 GB9900165D0 (en) 1999-02-24
GB2345576A true GB2345576A (en) 2000-07-12

Family

ID=10845593

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9900165A Withdrawn GB2345576A (en) 1999-01-05 1999-01-05 Heat-sink of ICs and method of mounting to PCBs

Country Status (1)

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GB (1) GB2345576A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1395098A1 (en) * 2002-09-02 2004-03-03 Catem GmbH & Co.KG Electrical heating for vehicle
EP1503615A2 (en) * 2003-07-31 2005-02-02 Kathrein-Werke KG Circuit board having a cooled component, particularly a SMD-component
WO2006059923A1 (en) * 2004-11-30 2006-06-08 Telefonaktiebolaget Lm Ericsson (Publ) A printed board assembly with improved heat dissipation
WO2015120582A1 (en) * 2014-02-12 2015-08-20 华为终端有限公司 Printed circuit board and method for manufacturing printed circuit board
CN104883133A (en) * 2015-06-19 2015-09-02 苏州英诺迅科技股份有限公司 GaAs and LDMOS/GaN mixed integrated microwave amplifier based on PCB process
CN105283031A (en) * 2014-07-11 2016-01-27 台达电子工业股份有限公司 Heat dissipation module and combination method
EP3496140A1 (en) * 2017-12-05 2019-06-12 NXP USA, Inc. Microelectronic components having integrated heat dissipation posts, systems including the same, and methods for the fabrication thereof

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10504813B2 (en) * 2016-09-30 2019-12-10 Astec International Limited Heat sink assemblies for surface mounted devices

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB821830A (en) * 1955-08-29 1959-10-14 Mullard Radio Valve Co Ltd Improvements in and relating to semi-conductor devices
GB851544A (en) * 1957-10-28 1960-10-19 English Electric Valve Co Ltd Improvements in or relating to semi-conductor devices
GB2135525A (en) * 1983-02-22 1984-08-30 Smiths Industries Plc Heat-dissipating chip carrier substrates
EP0321899A1 (en) * 1987-12-22 1989-06-28 Alcatel Cit Method and cooling device for an integrated-circuit housing
US5287242A (en) * 1991-05-01 1994-02-15 Sony Corporation Degaussing apparatus
US5514327A (en) * 1993-12-14 1996-05-07 Lsi Logic Corporation Powder metal heat sink for integrated circuit devices
WO1997012504A1 (en) * 1995-09-29 1997-04-03 Intel Corporation Method for surface mounting a heatsink to a printed circuit board
US5784255A (en) * 1995-12-04 1998-07-21 Integrated Device Technology, Inc. Device and method for convective cooling of an electronic component

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB821830A (en) * 1955-08-29 1959-10-14 Mullard Radio Valve Co Ltd Improvements in and relating to semi-conductor devices
GB851544A (en) * 1957-10-28 1960-10-19 English Electric Valve Co Ltd Improvements in or relating to semi-conductor devices
GB2135525A (en) * 1983-02-22 1984-08-30 Smiths Industries Plc Heat-dissipating chip carrier substrates
EP0321899A1 (en) * 1987-12-22 1989-06-28 Alcatel Cit Method and cooling device for an integrated-circuit housing
US5287242A (en) * 1991-05-01 1994-02-15 Sony Corporation Degaussing apparatus
US5514327A (en) * 1993-12-14 1996-05-07 Lsi Logic Corporation Powder metal heat sink for integrated circuit devices
WO1997012504A1 (en) * 1995-09-29 1997-04-03 Intel Corporation Method for surface mounting a heatsink to a printed circuit board
US5784255A (en) * 1995-12-04 1998-07-21 Integrated Device Technology, Inc. Device and method for convective cooling of an electronic component

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1395098A1 (en) * 2002-09-02 2004-03-03 Catem GmbH & Co.KG Electrical heating for vehicle
US6919535B2 (en) 2002-09-02 2005-07-19 Catem Gmbh & Co. Kg Electric heating for motor vehicles
EP1503615A2 (en) * 2003-07-31 2005-02-02 Kathrein-Werke KG Circuit board having a cooled component, particularly a SMD-component
EP1503615A3 (en) * 2003-07-31 2005-07-27 Kathrein-Werke KG Circuit board having a cooled component, particularly a SMD-component
WO2006059923A1 (en) * 2004-11-30 2006-06-08 Telefonaktiebolaget Lm Ericsson (Publ) A printed board assembly with improved heat dissipation
WO2015120582A1 (en) * 2014-02-12 2015-08-20 华为终端有限公司 Printed circuit board and method for manufacturing printed circuit board
CN105283031A (en) * 2014-07-11 2016-01-27 台达电子工业股份有限公司 Heat dissipation module and combination method
CN104883133A (en) * 2015-06-19 2015-09-02 苏州英诺迅科技股份有限公司 GaAs and LDMOS/GaN mixed integrated microwave amplifier based on PCB process
EP3496140A1 (en) * 2017-12-05 2019-06-12 NXP USA, Inc. Microelectronic components having integrated heat dissipation posts, systems including the same, and methods for the fabrication thereof
US10861764B2 (en) 2017-12-05 2020-12-08 Nxp Usa, Inc. Microelectronic components having integrated heat dissipation posts and systems including the same

Also Published As

Publication number Publication date
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