Flexible heat sink

• US 6,919,504 B2
• Filed: 12/19/2002
• Issued: 07/19/2005
• Est. Priority Date: 12/19/2002
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Soo, Philip P., Liu, Yaoqi J., McCutcheon, Jeffrey W., Narum, Timothy N.
• Primary Examiner(s): Nguyen, Chau N.
• Application Number:
  US10/324,759
• Publication Number:
  US 20040118579A1
• Time in Patent Office: 943 Days
• Field of Search: 174/163, 357/81, 357/82, 357/79, 165/185
• US Class Current: 174/16.3
• CPC Class Codes: F28D 15/0241 the tubes being flexible
• CPC Class Codes: F28F 3/022 the means being wires or pins
• CPC Class Codes: F28F 3/04 the means being integral with the element
• CPC Class Codes: H01L 2224/73253 Bump and layer connectors
• CPC Class Codes: H01L 23/3677 Wire-like or pin-like cooling fins or heat sinks
• CPC Class Codes: H01L 23/3733 having a heterogeneous or anisotropic structure, e.g. powder or fibres in a matrix, wire mesh, porous structures H01L23/3732, H01L23/3737 take precedence
• CPC Class Codes: H01L 23/3735 Laminates or multilayers, e.g. direct bond copper ceramic substrates
• CPC Class Codes: H01L 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/0102 Calcium [Ca]
• CPC Class Codes: H01L 2924/01021 Scandium [Sc]
• CPC Class Codes: H01L 2924/01025 Manganese [Mn]
• CPC Class Codes: H01L 2924/01046 Palladium [Pd]
• CPC Class Codes: H01L 2924/01055 Cesium [Cs]
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: Y10T 29/49366 Sheet joined to sheet

Abstract

Provided is a flexible heat sink article comprising a base comprising a polymer and a plurality of polymeric protrusions extending away from the base, each protrusion having a major dimension and a minor dimension. The base comprises thermally conductive particles, and the protrusions comprise non-spherical thermally conductive particles substantially aligned in the direction of the major dimension within the protrusions. A thermal interface material may be provided contiguous with the base. Also provided is a flexible heat sink article comprising a base comprising a polymer and having a first surface and a second surface, a plurality of polymeric protrusions extending away from the first surface of the base, each protrusion having a major and a minor dimension, and a metallic layer contiguous with the second surface of the base, wherein the base and the protrusions comprise thermally conductive particles. Also provided is a method of making a flexible heat sink.

Claims

1. A flexible heat sink article comprising:

a base comprising a polymer;

a plurality of polymeric protrusions extending away from the base, each protrusion having a major dimension and a minor dimension; and

a thermal interface material contiguous with the base,

wherein the polymer of the base comprises thermally conductive particles,

wherein the polymer of the protrusions comprises non-spherical thermally conductive particles substantially aligned in the direction of the major dimension within the protrusions,

wherein the thermal interface material is provided in two or more intermittent regions and includes two or more of a pressure sensitive adhesive, hot melt adhesive, low surface energy adhesive, epoxy, thermal bond film, phase change material, grease, and eutectic alloy phase change material, wherein the thermal interface material, and

wherein the heat sink flexibility allows bending to a radius of less than about 30 cm at room temperature without significantly adversely affecting the heat sink function.

2. The article of claim 1 wherein the thermal interface material comprises caliper variations.

3. The article of claim 2 wherein the caliper variations arc selected to improve one or more properties selected from heat flow, adhesion, surface wet-out, contact area, and flexibility.

4. The article of claim 1 wherein the thermally conductive particles are selected from carbon black, carbon fibers, coated carbon fibers, diamond, ceramic fiber mesh, ceramics, boron nitride, aluminum oxide, silicon carbide, aluminum nitride, aluminum trihydrate, magnesium hydroxide, metals, metal foils, and combinations thereof.

5. The article of claim 1 further comprising a metallic layer, a scrim, or a combination thereof, selected to reduce at least one of EMI, RFI, and thermal conductivity, said scrim optionally selected from nickel or nickel-coated scrims, carbon scrims, nickel-coated carbon scrims, and combinations thereof.

6. The article of claim 1 wherein the thermal interface material comprises an electrically conductive adhesive.

7. The article of claim 6 wherein the adhesive further comprises thermally conductive particles of sufficient size to increase thermally conductivity as compared to the adhesive without thermally conductive particles between a substrate and the heat sink article, optionally wherein the particles are contained within the adhesive and impinge the base and optionally impinge the surface of the adhesive opposite the base.