Heat sink with thermally compliant beams

• US 7,749,812 B2
• Filed: 08/06/2007
• Issued: 07/06/2010
• Est. Priority Date: 08/06/2007
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Chainer, Timothy J
• Primary Examiner(s): Dang; Phuc T
• Application Number:
  US11/834,552
• Publication Number:
  US 20090039499A1
• Time in Patent Office: 1,065 Days
• Field of Search: 438/118, 438/121, 438/122, 257/706, 257/707, 257/E23.193, 361/704, 361/719
• US Class Current: 438/122
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 23/3677 Wire-like or pin-like cooling fins or heat sinks
• CPC Class Codes: H01L 23/433 Auxiliary members in containers characterised by their shape, e.g. pistons
• 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 2924/01004 Beryllium [Be]
• CPC Class Codes: H01L 2924/10253 Silicon [Si]

Abstract

A heat dissipating structure includes: a heat spreader; and a plurality of compliant beams attached to the heat spreader. The beams are formed of a high-conductive material such that a maximum stress of each beam is less than a fatigue stress of the high-conductive material; said beams are placed at an angle relative to a chip surface such that the beams are able to exert bending compliance in response to x, y, and z forces exerted upon them. The structure also includes a thermal material interface for bonding said structure to the chip surface. Both the heat spreader and the compliant beams can be machined from a copper block. An alternative heat dissipating structure includes compliant beams soldered to the chip surface.

Claims

1. A method of producing a heat dissipating structure, the method comprising:

shaping a plurality of compliant beams;

attaching the plurality of compliant beams to a surface of a heat spreader, wherein the compliant beams are formed of a high-conductive material such that a maximum stress of each compliant beam is less than a fatigue stress of the high-conductive material; and

placing the compliant beams in a position such that at least a part of each beam is in a non-perpendicular angle relative to a chip surface such that the compliant beams are able to exert bending compliance in response to x, y, and z forces exerted upon them.

2. The method of claim 1 further comprising:

placing the heat spreader under a bearing weight to exert z forces on the compliant beams to bring them into physical contact with the chip surface.

3. The method of claim 1 wherein the placing element comprises:

placing the compliant beams at an angle lying between forty-five degrees and eighty-five degrees relative to the chip surface; and

wherein a bottom surface of each compliant beam is parallel to the chip surface.

4. The method of claim 1 further comprising:

placing solder balls between the heat dissipating structure and the chip surface for bonding said heat dissipating structure to the chip surface.