Wire heat sink assembly and method of assembling

• US 6,249,436 B1
• Filed: 08/30/1999
• Issued: 06/19/2001
• Est. Priority Date: 08/30/1999
• Status: Expired due to Fees

• Current Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Bollesen, Vernon
• Primary Examiner(s): Picard, Leo P.
• Assistant Examiner(s): CHERVINSKY, BORIS LEO
• Application Number:
  US09/385,480
• Time in Patent Office: 659 Days
• Field of Search: 361/704, 361/707, 361/709, 361/710, 361/715, 361/719-1, 361/721, 165/80.2, 165/80.3, 174/16.3, 257/706, 257/707, 257/712, 257/713, 257/718, 257/719-1, 257/722, 257/727
• US Class Current: 361/720
• CPC Class Codes: H01L 23/4093 Snap-on arrangements, e.g. clips
• 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: Y10T 24/44017 with specific mounting means for attaching to rigid or semirigid supporting structure or structure-to-be-secured

Abstract

A heat sink assembly includes a heat sink, a circuit board and an integrated circuit package. The heat sink includes torque bars having locking features. The package is located between the heat sink and the circuit board and attached to a die attach area of the circuit board. A heat sink retainer has ends secured in the locking features of the torque bars. Tension in the retainer imparts torque on the heat sink which causes the heat sink to impart a downward force on the package. The retainer presses the heat sink down uniformly on the package. Further, the downward force applied by the heat sink to the package is countered by an equal upward force applied by a base section of the retainer on the circuit board. Since the base section is located directly opposite the die attach area, the upward force is transferred from the base section directly back to the heat sink without imparting any bending force on the circuit board.

Claims

1. A structure comprising:

a heat sink comprising;

a base having a plurality of aperture;

a plurality of torque bars extending from said base, each torque bar of said plurality of torque bars being adjacent an aperture of said plurality of apertures; and

a plurality of locking features, wherein each torque bar of said plurality of torque bars has a locking feature of said plurality of locking features;

a circuit board comprising a plurality of apertures;

a package comprising an electronic component;

wherein said package is located between said heat sink and said circuit board and attached to a die attach area of said circuit board; and

a retainer having a plurality of spring elements and a plurality of ends, each spring element of said plurality of spring elements passing through an aperture of said plurality of apertures in said circuit board and also through an aperture of said plurality of apertures in said base of said heat sink, wherein each end of said plurality of ends is secured in a locking feature of said plurality of locking features, wherein tension in said retainer imparts torque on said heat sink which causes said heat sink to impart a first force on said package, said first force being countered by a second force applied by a base section of said retainer on said circuit board directly opposite said die attach area.

2. The structure of claim 1 wherein said retainer passes through said circuit board at a distance from said die attach area.

3. A structure comprising:

a retainer comprising;

a plurality of ends;

a base section; and

a plurality of spring elements, wherein each spring element of said plurality of spring elements integrally connects an end of said plurality of ends to said base section; and

a heat sink comprising;

a base comprising a plurality of apertures; and

a plurality of torque bars extending from said base, each torque bar of said plurality of torque bars being adjacent an aperture of said plurality of apertures and comprising a locking feature of a plurality of locking features, said plurality of locking features securing said plurality of ends to said heat sink.

4. The structure of claim 3 wherein each locking feature of said plurality of locking features is a notch in a torque bar of said plurality of torque bars.

5. The structure of claim 4 wherein each end of said plurality of ends snaps into a notch of said plurality of notches to secure said retainer to said heat sink.

6. The structure of claim 3 wherein tension in said retainer presses each end of said plurality of ends into a locking feature of said plurality of locking features.

7. The structure of claim 6 further comprising:

a substrate; and

a package comprising an electronic component, said package being located between said heat sink and said substrate, wherein said retainer presses said heat sink towards said package without imparting a bending force on said substrate.

8. The structure of claim 3 further comprising a substrate, wherein each spring element of said plurality of spring elements passes through an aperture of a plurality of apertures in said substrate.

9. The structure of claim 8 further comprising a package comprising an electronic component, said package located between said heat sink and said substrate.

10. The structure of claim 9 wherein said package is attached to a die attach area of said substrate, said base section being located adjacent said substrate directly opposite said die attach area.

11. The structure of claim 10 further comprising a standoff located between said base section and said substrate.

12. The structure of claim 10 wherein each aperture of said plurality of apertures in said substrate are located at a distance from said die attach area.

13. The structure of claim 3 wherein said retainer is symmetric around a center line of said retainer.

14. The structure of claim 3 wherein said said retainer has the ability to return to its original form after being bent out of shape.

15. A structure comprising:

a heat sink having a plurality of torque bars and a plurality of locking features, wherein each torque bar of said plurality of torque bars has a locking feature of said plurality of locking features;

a circuit board;

a package comprising an electronic component;

wherein said package is located between said heat sink and said circuit board and attached to a die attach area of said circuit board; and

a retainer having a plurality of ends, wherein each end of said plurality of ends is secured in a locking feature of said plurality of locking features, said plurality of ends pressing said plurality of locking features in a first direction towards said package and in a second direction towards said circuit board, wherein tension in said retainer imparts torque on said heat sink which causes said heat sink to impart a first force on said package, said first force being countered by a second force applied by a base section of said retainer on said circuit board directly opposite said die attach area.

16. A method of pressing a heat sink into thermal contact with a package comprising an electronic component, said method comprising:

attaching said package to a die attach area of a substrate;

positioning said heat sink such that said package is located between said heat sink and said substrate; and

attaching a first end of a retainer to a locking feature of a first torque bar of said heat sink and a second end of said retainer to a locking feature of a second torque bar of said heat sink, said first end pressing said first locking feature in a first direction towards said package and in a second direction towards said substrate, said second end pressing said second locking feature in said first direction towards said package and in said second direction towards said substrate, wherein said first and second ends impart torque on said heat sink which causes said heat sink to impart a first force on said package, said first force being countered by a second force applied by a base section of said retainer on said substrate directly opposite said die attach area.

17. The method of claim 16 wherein said first force and said second force are applied without imparting a bending force to said substrate.

18. The method of claim 16 wherein said attaching comprises snapping said first end into said first locking feature and snapping said second end into said second locking feature.

19. The method of claim 18 wherein said attaching further comprises moving said first end away from said package and to said first locking feature and said second end away from said package to said second locking feature.

20. A method of pressing a heat sink into thermal contact with a package comprising an electronic component, said method comprising:

attaching said package to a die attach area of a substrate;

positioning said heat sink such that said package is located between said heat sink and said substrate, said heat sink comprises a plurality of torque bars and a plurality of locking feature, wherein each torque bar of said plurality of torque bars has a locking feature of said plurality of locking features;

spreading a plurality of ends of a retainer apart from one another; and

attaching said plurality of ends of said retainer to said heat sink by snapping each end of said plurality of ends into a locking feature of said plurality of locking features, said plurality of ends pressing said plurality of locking features in a first direction towards said package and in a second direction towards said substrate, wherein said plurality of ends impart torque on said heat sink which causes said heat sink to impart a first force on said package, said first force being countered by a second force applied by a base section of said retainer on said substrate directly opposite said die attach area.