Printed circuit board and heat sink arrangement

• US 5,796,582 A
• Filed: 11/21/1996
• Issued: 08/18/1998
• Est. Priority Date: 11/21/1996
• Status: Expired due to Fees

• Current Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Original Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Katchmar, Roman
• Primary Examiner(s): Thompson, Gregory D.
• Application Number:
  US08/755,429
• Time in Patent Office: 635 Days
• Field of Search: 165/80.2, 165/80.3, 165/185, 174/16.3, 174/252, 174/259, 257/706, 257/707, 257/713, 257/717-719, 257/722, 257/726, 257/727, 361/704-722, 361/767, 361/773
• US Class Current: 361/704
• CPC Class Codes: H05K 7/20463 Filling compound, e.g. potted resin
• CPC Class Codes: H05K 7/20509 Multiple-component heat spreaders; Multi-component heat-conducting support plates; Multi-component non-closed heat-conducting structures

Abstract

Making an assembly of a printed circuit board structure and heat sink structure by locating a thermally conductive surface release agent upon a side of one of the structures and causing a flowable thermally conductive material to flow through a hole in the heat sink and lie between the release agent and the other structure. The thermally conductive material lies in heat conductive contact with the release agent and with the other structure and in alignment with an electronic component which is to be cooled upon the board. The release agent ensures easy release of the printed circuit board structure from the heat sink structure for disassembly purposes. An assembly of the two structures is also covered.

Claims

1. A method of making an assembly of a printed circuit board structure and heat sink structure comprising:

providing a printed circuit board structure comprising a printed circuit board and an electronic component mounted upon a first side of the printed circuit board;

providing a heat sink structure with a hole defined through the heat sink structure;

disposing a thermally conductive surface release agent upon a first side of a selected one of the structures;

relatively disposing the printed circuit board structure and the heat sink structure with the first sides of the two structures facing towards and spaced from each other and with the hole having its axis extending in a direction generally towards the electronic component;

and creating a heat conductive path from the heat sink structure to the printed circuit board structure by causing a flowable thermally conductive material or compound to flow through the hole so as to occupy and be caused to remain in a spatial region;

a) between and in heat conductive contact with the thermally conductive surface release agent on one side of the spatial region and in thermally conductive contact with the structure disposed on the other side of the spatial region; and

b) in alignment with the electronic component.

2. A method according to claim 1 wherein the thermally conductive release agent comprises a tape having a surface release feature on a first side of the tape, and the release agent is provided by heat conductively securing a second side of the tape to the first side of the selected structure, and subsequently causing the flowable thermally conductive material to occupy and remain within the spatial region, the conductive material after hardening intimately contact the release feature while being capable of being physically separated therefrom by the application of a separation force.

3. A method according to claim 1 comprising providing the release agent by coating the first side of the selected structure with a flowing settable release material and with the release material in a set condition, causing the flowable thermally conductive material to flow through the hole so as to occupy and remain in the spatial region, the thermally conductive material after at least partially hardening intimately contacting the set release material while being capable of being physically separated therefrom by the application of a separating force.

4. A method according to claim 3 wherein the release material is coated onto the first side of the selected structure only upon desired areas of the first side.

5. A method according to claim 1 further comprising providing a disassembly aperture in the heat sink in a positioned spaced from the hole, the disassembly aperture located for insertion of a tool to engage the printed circuit board structure to enable the printed circuit board structure and the heat sink structure to be urged apart during which the thermally conductive material becomes removed from the release agent.

6. A printed circuit board structure and heat sink structure assembly comprising:

a structure of printed circuit board and an electronic component detachably mounted upon the printed circuit board;

a heat sink structure with a hole defined through the heat sink structure for injection purposes;

the two structures disposed with first sides of the structures face-to-face and spaced-apart with the hole extending in a direction generally towards the electronic component;

and thermally conductive material that has flowed through the hole to be disposed between the two structures and occupy a spatial region extending across the hole to provide a heat conductive bridge between the two structures and in alignment with the electronic component, the thermally conductive material held away from a first side of a selected one of the structures by a thermally conductive surface release agent which is disposed in thermal conductive engagement both with the first side of the selected structure and with the thermally conductive material while being capable of being physically separated from the thermally conductive material by the application of a separating force.

7. An assembly according to claim 6 wherein the thermally conductive release agent comprises a tape having a surface release feature in contact with the thermally conductive material and the tape upon the other side is heat conductively secured to the first side of the selected one of the two structures.

8. An assembly according to claim 6 wherein the thermally conductive release agent is provided by a coating on the first side of the selected structure, the coating being in a set condition and lying on its two sides in intimate heat conductive relationship with the thermally conductive material and with the first side of the selected structure.

9. An assembly according to claim 8 wherein the release agent is provided as a coating only upon desired areas of the first side of the selected structure.

10. An assembly according to claim 6 further comprising a disassembly aperture in the heat sink in a position spaced from the hole, the disassembly aperture located for insertion of a tool to engage the printed circuit board structure so as to apply the separation force against the printed circuit board structure and urge the printed circuit board structure and the heat sink structure apart by separation of the thermally conductive material from the release agent.