Memory module assembly including heat sink attached to integrated circuits by adhesive

• US 7,215,551 B2
• Filed: 09/29/2004
• Issued: 05/08/2007
• Est. Priority Date: 09/29/2004
• Status: Expired due to Fees

• Current Assignee: Super Talent Technology, Corporation
• Original Assignee: Super Talent Electronics, Inc.
• Inventors: Ni, Jim, Wang, Kuang-Yu, Chiou, Ren-Kang
• Primary Examiner(s): Vortman; Anatoly
• Application Number:
  US10/956,893
• Publication Number:
  US 20060067054A1
• Time in Patent Office: 951 Days
• Field of Search: 361/707, 257/707
• US Class Current: 361/707
• CPC Class Codes: H01L 23/3672 Foil-like cooling fins or heat sinks being part of lead-frames H01L23/49568
• CPC Class Codes: H01L 23/42 Fillings or auxiliary members in containers or encapsulations selected or arranged to facilitate heating or cooling
• CPC Class Codes: H01L 25/105 the devices being of a type provided for in group H01L27/00
• 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: H05K 7/20509 Multiple-component heat spreaders; Multi-component heat-conducting support plates; Multi-component non-closed heat-conducting structures

Abstract

A memory module assembly includes two-plate heat sink attached to one or more of the integrated circuits (e.g., memory devices) of a memory module PCBA by adhesive. The adhesive is either heat-activated or heat-cured. The adhesive is applied to either the memory devices or the heat-sink plates, and then compressed between the heat-sink plates and memory module using a fixture. The fixture is then passed through an oven to activate/cure the adhesive.

Claims

1. A memory module assembly comprising:

a memory module printed circuit board assembly (PCBA) including;

a substrate having opposing first and second surfaces, a plurality of wiring traces formed on the first and second surfaces, at least some of the wiring traces being connected to metal contact pads formed along a connector edge of the substrate, and

a plurality of first integrated circuit (IC) devices mounted on the first surface of the substrate such that an upper surface of each of the plurality of first IC devices is parallel to the first surface of the substrate;

a first heat-sink plate having a planar underside surface; and

a plurality of adhesive portions, each adhesive portion being sandwiched between the planar underside surface of the first heat-sink plate and the upper surface of an associated IC device of said plurality of first IC devices such that the first heat-sink plate is rigidly secured to the memory module by the plurality of adhesive portions,

wherein each of the plurality of adhesive portions comprises one of a heat-activated adhesive material and a heat-cured adhesive material.

2. The memory module assembly according to claim 1, wherein the heat-activated adhesive material is characterized by exhibiting a first adherence when heated to a first temperature, and exhibiting a second adherence when subsequently cooled to a second temperature, wherein the first adherence is lower than the second adherence, and the first temperature is higher than the second temperature.

3. The memory module assembly according to claim 1, wherein the heat-cured adhesive material is characterized by exhibiting a first adherence when applied, and exhibiting a second adherence when subjected to heating, the first adherence being lower than the second adherence.

4. The memory module assembly according to claim 1, further comprising a fastener connected between the first heat-sink plate and the memory module.

5. The memory module assembly according to claim 1, wherein the first heat-sink plate is mounted onto the memory module PCBA such that the first heat-sink plate substantially overlaps the first surface in such a way that the plurality of first IC devices are covered by the first heat-sink plate, and the connector edge is exposed such that the contact pads are exposed for pluggable insertion into a host socket.

6. The memory module assembly according to claim 1,

wherein an upper edge of the first heat-sink plate is substantially aligned with an upper edge of the substrate, and

wherein the first heat-sink plate further comprises at least one wall extending from at least one of the upper edge and side edges of the first heat-sink plate, and

wherein said at least one wall extends substantially perpendicular to the planar underside surface.

7. The memory module assembly according to claim 6, wherein said at least one wall contacts the first surface of the substrate.

8. The memory module assembly according to claim 1,

wherein the memory module further comprises a plurality of second IC devices mounted on the second surface of the substrate such that an upper surface of each of the plurality of second IC devices defines a plane that is parallel to the second surface, and

wherein the memory module assembly further comprises a second heat-sink plate having a second planar underside surface, and a plurality of second heat-activated adhesive portions, each of said second heat-activated adhesive portions being sandwiched between the second planar underside surface and the upper surface of an associated IC device of said plurality of second IC devices such that the second heat-sink plate is rigidly secured to the memory module by the plurality of second adhesive portions.

9. The memory module assembly according to claim 1, wherein the memory module PCBA comprises one of a Double Data Rate (DDR) device, a second-generation double data rate (DDR2) device, a Single Inline Memory Module (SIMM) device, a Dual Inline Memory Module (DIMM) device, a Small Outline DIMM (SODIMM) device, and a Fully-Buffered DIMM (FB-DIMM) device.

10. A memory module assembly comprising:

a memory module printed circuit board assembly (PCBA) including;

a substrate having opposing first and second surfaces, a plurality of wiring traces formed on the first and second surfaces, at least some of the wiring traces being connected to metal contact pads formed along a connector edge of the substrate, and

a plurality of first integrated circuit (IC) devices mounted on the first surface of the substrate such that an upper surface of each of the plurality of first IC devices is parallel to the first surface of the substrate;

a first heat-sink plate having a planar underside surface; and

a plurality of adhesive portions, each adhesive portion being sandwiched between the planar underside surface of the first heat-sink plate and the upper surface of an associated IC device of said plurality of first IC devices such that the first heat-sink plate is rigidly secured to the memory module by the plurality of adhesive portions,

wherein the first heat-sink plate is secured to the memory module solely by the plurality of adhesive portions.

11. The memory module assembly according to claim 10, wherein the first heat-sink plate comprises a peripheral region surrounding a depression region, the depression region having an inside concave surface and an outside convex surface, and wherein the planar underside surface is located on the outside convex surface of the depression region.

12. The memory module assembly according to claim 11, wherein the depression region of the first heat-sink plate is formed such that the planar underside surface contacts the upper surface of each of the plurality of first IC devices.

13. The memory module assembly according to claim 10, wherein an upper edge of the first heat-sink plate extends over an upper edge of the substrate such that an opening is defined between the first heat-sink plate and the first surface of the substrate adjacent to an upper edge of the first heat-sink plate.

14. The memory module assembly according to claim 13, wherein the first heat-sink plate further comprises a plurality of ribs extending from the upper edge toward the substrate.

15. The memory module assembly according to claim 13, wherein the first heat-sink plate further comprises a plurality of walls extending from the upper edge of the first heat-sink plate at an acute angle relative to the planar underside surface.

16. The memory module assembly according to claim 10, further comprising a thermal interface material sandwiched between the planar underside surface of the first heat-sink plate and the upper surface of a second IC device of said plurality of first IC devices,

wherein each said adhesive portion has a first thermal conductivity, and

wherein the thermal interface material has a second thermal conductivity, the first thermal conductivity being lower than the second thermal conductivity.

17. The memory module assembly according to claim 10, further comprising a thermal interface material sandwiched between the planar underside surface of the first heat-sink plate and the upper surface of a second IC device of said plurality of first IC devices,

wherein each said adhesive portion has a first adhesion between the planar underside surface of the first heat-sink plate and the upper surface of the first IC device, and

wherein the thermal interface material has a second adhesion between the planar underside surface of the first heat-sink plate and the upper surface of the second IC device, the first adhesion being higher than the second adhesion.