Integral design features for heatsink attach for electronic packages

• US 6,373,703 B2
• Filed: 01/03/2001
• Issued: 04/16/2002
• Est. Priority Date: 12/17/1997
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: MacQuarrie, Stephen Wesley, Kosteva, Stephen John, Johnson, Eric Arthur
• Primary Examiner(s): THOMPSON, GREGORY D
• Application Number:
  US09/753,642
• Publication Number:
  US 20010005312A1
• Time in Patent Office: 468 Days
• Field of Search: 165/80.2, 165/80.3, 165/185, 174/16.3, 361/697, 361/704-705, 361/707-710, 361/714-718, 361/722, 257/706-707, 257/712-713, 257/718-719, 257/722, 257/726-727, 257/796
• US Class Current: 361/704
• CPC Class Codes: H01L 2224/056 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 2224/73253 Bump and layer connectors
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/85399 Material
• CPC Class Codes: H01L 23/4093 Snap-on arrangements, e.g. clips
• CPC Class Codes: H01L 24/48 of an individual wire connector
• 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 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/10253 Silicon [Si]
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: H01L 2924/15311 being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/1815 : Shape
• CPC Class Codes: H01L 2924/18161 : of a flip chip
• CPC Class Codes: H01L 2924/207 : Diameter ranges

Abstract

An apparatus and method attaching a heatsink to a surface of an electronic package comprising a substrate, an integrated circuit chip attached to the surface of the substrate, an encapsulant encapsulating the integrated circuit chip and contacting at least a portion of the surface of the substrate, and an orifice formed in the top portion of the encapsulant to attach the heatsink to the surface of the electronic package. The heatsink may be attached and removed as desired to allow for package identification or rework.

Claims

1. An electronic package assembly comprising:

a substrate having a first surface and a second surface;

an integrated circuit chip having a top surface;

first attaching means for attaching the integrated circuit chip to the first surface of the substrate;

encapsulating means for encapsulating the integrated circuit chip, the encapsulating means contacting at least a portion of the first surface of the substrate;

an orifice formed in a top portion of the encapsulating means, the orifice partially penetrating a surface of the encapsulating means;

heat dissipating means disposed on the top portion of the encapsulating means; and

second attaching means detachably coupled to the orifice, the second attaching means aligned with and separate from the heat dissipating means to maintain the heat dissipating means in contact with the top portion of the encapsulating means.

2. The electronic package assembly of claim 1, wherein the substrate is a laminated substrate having a plurality of layers.

3. The electronic package assembly of claim 2, wherein the substrate is a polymer.

4. The electronic package assembly of claim 1, wherein the integrated circuit chip is a wirebond chip having a lower surface and the first attaching means physically bonds the lower surface of the wirebond chip to the first surface of the substrate and electrically connects the top surface of the wirebond chip to the first surface of the substrate.

5. The electronic package assembly of claim 1, wherein the encapsulating means is an overmold formed on the top surface of the integrated circuit chip and on the first surface of the substrate.

6. The electronic package assembly of claim 5, wherein the overmold is a polymer.

7. The electronic package assembly of claim 1, further comprising heat transfer means disposed between the heat dissipating means and the overmold.

8. The electronic package assembly of claim 7, wherein the heat transfer means is one of an epoxy, an acrylic, a thermal grease, a conductive pad and a thermal tape.

9. The electronic package assembly of claim 1, further comprising third attaching means for attaching the second surface of the substrate to a circuit board.

10. The electronic package assembly of claim 9, wherein the third attaching means is a ball grid array (BGA).

11. An electronic package assembly comprising:

a substrate having a first surface and a second surface;

an integrated circuit chip having a top surface;

first attaching means for attaching the integrated circuit chip to the first surface of the substrate;

an overmold formed on the top surface of the integrated circuit chip and on the first surface of the substrate for encapsulating the integrated circuit chip, the overmold contacting at least a portion of the first surface of the substrate;

a slot formed in a top portion of the overmold, the slot partially penetrating a surface of overmold;

heat dissipating means disposed on the top portion of the overmold, and

second attaching means detachably coupled to the slot, the second attaching means aligned with and separate from the heat dissipating means to maintain the heat dissipating means in contact with the top portion of the overmold.

12. The electronic package assembly of claim 11, further comprising heat transfer means disposed between the heat dissipating means and the overmold.

13. The electronic package assembly of claim 12, wherein the heat transfer means is one of an epoxy, an acrylic, a thermal grease, a conductive pad and a thermal tape.

14. The electronic package assembly of claim 11, wherein the second attaching means engages the slot formed in the overmold.

15. The electronic package assembly of claim 14, wherein the second attaching means is at least one unitary resilient member.

16. The electronic package assembly of claim 15, wherein the second attaching means is one of a metal and a polymer.

17. A method for packaging an electronic assembly comprising the steps of:

(a) attaching an integrated circuit chip to a first surface of a substrate using a first attachment,

(b) encapsulating the integrated circuit chip using an encapsulant contacting the integrated circuit chip and at least a portion of the first surface of the substrate, and

(c) forming a second attachment in a top portion of the encapsulant, the attachment partially penetrating the top portion of the encapsulant;

(d) detachably coupling a heat dissipator to the encapsulant using a third attachment; and

(e) disposing heat transfer means between the encapsulant and the heat dissipator.

18. An electronic package assembly comprising:

a substrate having a first surface and a second surface;

an integrated circuit chip having a top surface;

first attaching means for attaching the integrated circuit chip to the first surface of the substrate;

an overmold formed on the top surface of the integrated circuit chip and on the first surface of the substrate for encapsulating the integrated circuit chip, the encapsulating means contacting at least a portion of the first surface of the substrate;

an orifice formed in a top portion of the overmold;

heat dissipating means disposed over the top portion of the overmold;

heat transfer means disposed between the heat dissipating means and the overmold; and

second attaching means detachably coupled to the orifice, the second attaching means aligned with the heat dissipating means and maintaining the heat dissipating means in contact with the top portion of the overmold.

19. An electronic package assembly comprising:

a substrate having a first surface and a second surface;

an integrated circuit chip having a top surface;

first attaching means for attaching the integrated circuit chip to the first surface of the substrate;

an overmold formed on the tope surface of the integrated circuit chip and on the first surface of the substrate for encapsulating the integrated circuit chip, the overmold contacting at least a portion of the first surface of the substrate;

a slot formed in a top portion of the overmold;

heat dissipating means disposed on the top portion of the overmold;

second attaching means detachably coupled to the overmold, the second attaching means aligned with the heat dissipating means and maintaining the heat dissipating means in contact with the top portion of the overmold; and

heat transfer means disposed between the heat dissipating means and the overmold.