Heat sink structure for cooling a substrate and an electronic apparatus having such a heat sink structure

• US 5,894,882 A
• Filed: 05/17/1996
• Issued: 04/20/1999
• Est. Priority Date: 02/19/1993
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Kikuchi, Shunichi, Kanda, Takashi, Yoshimura, Hideaki, Seyama, Kiyotaka, Nori, Hitoshi, Hirano, Minoru
• Primary Examiner(s): Leo, Leonard R.
• Application Number:
  US08/650,029
• Time in Patent Office: 1,068 Days
• Field of Search: 165/80.3, 165/185, 174/16.3, 257/713, 257/722, 361/690, 361/697, 361/703, 361/704
• US Class Current: 165/80.3
• CPC Class Codes: F28F 3/027 with openings, e.g. louvered corrugated fins; Assemblies of corrugated strips
• CPC Class Codes: H01L 23/3672 Foil-like cooling fins or heat sinks being part of lead-frames H01L23/49568
• 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

Abstract

A heat sink structure of a module substrate includes a plurality of stripe-like bottom regions extending in a longitudinal direction and repeated in a lateral direction with a predetermined pitch, a plurality of stripe-like top regions extending in said longitudinal direction and repeated in the lateral direction with said predetermined pitch, such that the stripe-like bottom regions and the stripe-like top regions are repeated alternately in the lateral direction, wherein the stripe-like top regions and the stripe-like bottom regions have respective lateral edges that are connected with each other by cooling fins.

Claims

1. A heat sink structure having first and second opposite ends spaced apart in a longitudinal direction, comprising:

plural cooling fins extending in substantially parallel relationship with respect to each other in the longitudinal direction from the first end to the second end of said heat sink structure, each as an effectively continuous planar surface, and spaced in a lateral direction, each cooling fin having a top edge and a bottom edge extending in said longitudinal direction;

a plurality of bottom members respectively interconnecting corresponding pairs of adjacent said cooling fins at said respective bottom edges thereof and extending in said longitudinal direction from said first end to said second end of said heat sink structure and having corresponding bottom surfaces adapted for contact with a heat source for conducting heat generated by said heat source to said corresponding pairs of cooling fins;

a plurality of ceiling members, each ceiling member comprising a substantially continuous planar surface, respectively interconnecting corresponding pairs of adjacent said cooling fins at said respective top edges thereof and extending from said first end to said second end of said heat sink structure, and defining therewith corresponding, substantially completely surrounded air flow paths in the longitudinal direction between said heat sink structure and said heat source and extending from said first end to said second end of said heat sink structure, any airflow in a direction transverse to the longitudinal airflow paths being insubstantial relatively to the airflow in the airflow path; and

each of said bottom members being segmented into a plurality of bottom segments by a corresponding plurality of first cutouts disposed in parallel in the lateral direction and spaced in the longitudinal direction by a first pitch, each first cutout extending through the corresponding bottom member and through the pair of cooling fins interconnected thereby from the respective bottom edges thereof and toward the respective top edges thereof, each of said plurality of ceiling members being segmented into a plurality of ceiling segments by a corresponding plurality of pairs of second cutouts disposed in parallel in the lateral direction and spaced in the longitudinal direction by the first pitch, each ceiling segment being a continuous planar surface and extending continuously between successive pairs of second cutouts and the second cutouts of each pair being separated by a second pitch, substantially smaller than the first pitch, and defining therebetween a bridging ceiling portion of said corresponding ceiling member, each pair of second cutouts, further, extending on each of said pair of adjacent cooling fins, interconnected by said corresponding ceiling member, generally vertically from said respective top edges and toward said respective bottom edges thereof and being grouped, in each of the pair of adjacent cooling fins, with a respective said first cutout disposed therebetween and defining a corresponding deformable part having an inverted U-shaped configuration, the plural groups of corresponding pairs of second cutouts and respective first cutouts defining respective, plural deformable parts in said corresponding cooling fins spaced in said longitudinal direction at the first pitch and defining and flexibly interconnecting successive cooling fin segments, each successive cooling fin segment extending as a continuous planar surface continuously between successive said deformable parts.

2. A heat sink structure as claimed in claim 1, wherein said bottom connection members and said ceiling members are disposed in alternate succession in said lateral direction such that each pair of cooling fins interconnected by a corresponding said bottom connection member and a next successive pair of cooling fins, interconnected by the next successive said ceiling member, share one cooling fin in common.

3. A heat sink structure as claimed in claim 1, wherein said bottom connection members and said ceiling members are disposed in repeating, alternate succession in said lateral direction.

4. A heat sink structure as claimed in claim 1, wherein the respective pluralities of first cutouts, formed in the plurality of bottom members and in the associated pairs of cooling fins respectively interconnected thereby, are aligned in the lateral direction and the respective pluralities of pairs of second cutouts, formed in the plurality of ceiling members and in the associated pairs of cooling fins respectively interconnected thereby, are aligned in the lateral direction.

5. A heat sink structure as claimed in claim 4, wherein each bridging ceiling portion, as defined by an associated pair of second cutouts, interconnects the laterally aligned deformable parts commonly defined by the same pair of second cutouts in the cooling fins interconnected by the corresponding ceiling member.

6. A heat sink structure as claimed in claim 5, wherein each cooling fin segment extends continuously to, and forms an integral connection with, the bottom segment defined by the adjacent and common, first cutouts.

7. A heat sink structure having first and second opposite ends spaced apart in a longitudinal direction, comprising:

a continuous sheet of heat conductive material configured to have a cross sectional configuration substantially of a square wave extending in a lateral direction in a plane which is perpendicular to the longitudinal direction and defining plural cooling fins, extending in parallel relationship in the longitudinal direction, and plural ceiling members and plural bottom members, extending in parallel relationship in the longitudinal direction and respectively interconnecting respective upper edges and respective lower edges of adjacent said cooling fins in alternating succession;

the bottom members having respective lower surfaces adapted for contact with a heat source and conducting heat generated by the heat source to the corresponding cooling fins interconnected thereby and the adjacent pairs of cooling fins interconnected by a corresponding ceiling member defining therewith, relatively to the heat source, a surrounded airflow path extending in the longitudinal direction;

each ceiling member and corresponding pair of adjacent cooling fins interconnected thereby having respective pluralities of cutouts therein, the respective plurality of cutouts in each ceiling member defining therein an alternating succession of plural ceiling segments and plural ceiling bridging portions, each ceiling bridging portion being spaced between and separating successive ceiling segments and the respective pluralities of cutouts, in the pair of adjacent cooling fins interconnected by a respective said ceiling member, defining in each thereof an alternating succession of plural cooling fin segments and plural deformable parts, each of an inverted U-shaped configuration, the deformable parts being spaced at a first pitch in the longitudinal direction and having a length in the longitudinal direction which is substantially smaller than the first pitch, respective deformable parts of the pair of adjacent cooling fins being aligned in the lateral direction with, and interconnected by, a bridging portion of the corresponding ceiling member and flexibly interconnecting the successive cooling fin segments, each ceiling segment being aligned in the lateral direction with, and integrally interconnecting respective cooling fin segments of, the pair of cooling fins interconnected by the corresponding ceiling member, the respective pluralities of cutouts having a minimal dimension in the longitudinal direction so as to minimize air flow passage transversely through the cooling fin and ceiling members while permitting thermally induced relative displacements between respective interconnected cooling fin segments and ceiling member segments.

8. A heat sink structure as claimed in claim 7, wherein said bottom connection members and said ceiling members are disposed in alternate succession in said lateral direction such that each pair of cooling fins, interconnected by a corresponding said bottom connection member, and a next successive pair of cooling fins, interconnected by the next successive said ceiling member, share one cooling fin in common.

9. A heat sink structure as claimed in claim 7, wherein said bottom connection members and said ceiling members are disposed in repeating, alternate succession in said lateral direction.

10. A heat sink structure as claimed in claim 7, wherein each bottom member has a corresponding plurality of cutouts therein defining corresponding bottom segments and each cooling fin segment extends continuously to and forms an integral connection with a laterally aligned, respective bottom segment.

11. A heat sink structure having first and second opposite ends spaced apart in a longitudinal direction, comprising:

a continuous sheet of heat conductive material configured to have a cross sectional configuration substantially of a square wave extending in a lateral direction in a plane which is perpendicular to the longitudinal direction and defining plural cooling fins, extending in parallel relationship in the longitudinal direction, and plural ceiling members and plural bottom members, extending in parallel relationship in the longitudinal direction and respectively interconnecting respective upper edges and respective lower edges of adjacent said cooling fins in alternating succession;

the bottom members having respective lower surfaces adapted for contact with a heat source and conducting heat generated by the heat source to the corresponding cooling fins interconnected thereby and the adjacent pairs of cooling fins interconnected by a corresponding ceiling member defining therewith, relatively to the heat source, a surrounded airflow path extending in the longitudinal direction;

the ceiling and bottom members having respective pluralities of cutouts therein, extending in the lateral direction and spaced in parallel relationship in the longitudinal direction and defining plural ceiling segments in each of the plurality of ceiling members and plural bottom segments in each of the plurality of bottom members, the respective pluralities of segments of the ceiling and bottom members being aligned in the lateral direction;

the cooling fins having pluralities of cutouts therein aligned with the respective pluralities of cutouts in the ceiling and bottom members and defining a corresponding plurality of cooling fin segments, aligned in the lateral direction with and interconnecting corresponding ceiling and bottom member segments, the plurality of cutouts in each of the cooling fins furthermore defining a plurality of deformable parts spaced at a first pitch in the longitudinal direction, each of an inverted U-shaped configuration and having a length in the longitudinal direction which is substantially smaller than the first pitch, separating and flexibly interconnecting respective, successive cooling fin segments; and

each cutout, of the respective pluralities of cutouts in the ceiling members and the cooling fins, having a minimal dimension in the longitudinal direction so as to minimize air flow passage transversely through the cooling fin and ceiling members while permitting thermally induced relative displacements between the successive cooling fin segments and ceiling member segments.

12. A heat sink structure as claimed in claim 11, wherein said bottom connection members and said ceiling members are disposed in alternate succession in said lateral direction such that each pair of cooling fins, interconnected by a corresponding said bottom connection member, and a next successive pair of cooling fins, interconnected by the next successive said ceiling member, share one cooling fin in common.

13. A heat sink structure as claimed in claim 11, wherein said bottom connection members and said ceiling members are disposed in repeating, alternate succession in said lateral direction.

14. A heat sink structure as claimed in claim 11, wherein each bottom member has a corresponding plurality of cutouts therein defining corresponding bottom segments and each cooling fin segment extends continuously to and forms an integral connection with a laterally aligned, respective bottom segment.

15. A heat sink structure, comprising:

a sheet of heat transfer material formed to have a rectangular-wave-like cross section when viewed in a first, longitudinal direction and comprising plural cooling fins disposed in spaced, parallel relationship in a second, lateral direction transverse to the first, longitudinal direction, alternate pairs of adjacent fins being integrally interconnected respectively, by bottom members and ceiling members respectively defining, and lying in, a common bottom plane and a common ceiling plane substantially parallel to the bottom plane, both thereof substantially perpendicular to the cooling fins; and

the plural cooling fins and the associated bottom and ceiling members having plural deformable parts formed therein, spaced at a first pitch in the longitudinal direction, each deformable part separating and interconnecting corresponding, adjacent segments of the cooling fin and associated bottom and ceiling members, each deformable part being of a substantially smaller dimension in the longitudinal direction than the first pitch and having substantially less rigidity in the longitudinal direction than the segments of the cooling fins and associated bottom and ceiling members and permitting the heat sink structure to expand in the longitudinal direction by deformation of the deformable members producing relatively increased separation of the respective, adjacent segments of the cooling fins and associated bottom and ceiling members interconnected thereby; and

each pair of adjacent cooling fins and the respective ceiling member defining a substantially completely surrounded airflow path in the longitudinal direction, directing airflow therethrough in the longitudinal direction and restricting any airflow in the lateral direction to a relatively insubstantial amount.

16. A heat sink structure as recited in claim 15, wherein corresponding deformable parts of the respective, plural cooling fins are aligned in the lateral direction and are defined by respective first U-shaped slots lying in a first common plane in the lateral direction and transverse to the longitudinal direction, extending through the bottom members and the respective, adjacent cooling fins upwardly to a position adjacent the respective ceiling members and by respective, second and third inverted U-shaped slots lying respectively in second and third common planes parallel to and spaced symmetrically with respect to the first common plane and extending through the ceiling members and through the cooling fins to positions adjacent the bottom members and thereby defining a U-shaped configuration of each deformable part when viewed in the lateral direction.

17. A heat sink structure as recited in claim 16, wherein the pitch of the deformable members is a multiple of the