Morphing fillers and thermal interface materials

• US 6,797,758 B2
• Filed: 09/05/2001
• Issued: 09/28/2004
• Est. Priority Date: 04/05/2000
• Status: Expired

• Current Assignee: Henkel IP & Holding GmbH (Henkel AG & Co KGaA)
• Original Assignee: Berquist Company The (Henkel AG & Co KGaA)
• Inventors: Misra, Sanjay, Elahee, G M Fazley
• Primary Examiner(s): Cain, Edward J.
• Application Number:
  US09/946,879
• Publication Number:
  US 20030027910A1
• Time in Patent Office: 1,119 Days
• Field of Search: 524/404, 524/434, 524/439
• US Class Current: 524/404
• CPC Class Codes: F28F 13/00 Arrangements for modifying heat-transfer, e.g. increasing, decreasing F28F1/00 - F28F11/00 take precedence
• CPC Class Codes: F28F 2013/006 Heat conductive materials
• CPC Class Codes: H01B 3/301 Macromolecular compounds obtained by reactions forming a linkage containing sulfur with or without nitrogen, oxygen or carbon in the main chain of the macromolecule, not provided for in group H01B3/302
• CPC Class Codes: H01B 3/306 Polyimides or polyesterimides
• CPC Class Codes: H01L 23/3735 Laminates or multilayers, e.g. direct bond copper ceramic substrates
• CPC Class Codes: H01L 23/3736 Metallic materials H01L23/3732, H01L23/3733, H01L23/3735, H01L23/3737, H01L23/3738 take precedence
• CPC Class Codes: H01L 23/3737 Organic materials with or without a thermoconductive filler
• 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: H01L 2924/3011 Impedance
• CPC Class Codes: H05K 2201/0129 Thermoplastic polymer, e.g. auto-adhesive layer; Shaping of thermoplastic polymer
• CPC Class Codes: H05K 2201/0209 Inorganic, non-metallic particles
• CPC Class Codes: H05K 2203/0759 Forming a polymer layer by liquid coating, e.g. a non-metallic protective coating or an organic bonding layer
• CPC Class Codes: H05K 3/0061 onto a metallic substrate, e.g. a heat sink heat sinks for electric apparatus H05K7/20

Abstract

A thermally conductive mechanically compliant pad including a quantity of gallium and/or indium alloy liquid at temperatures below about 120° C. and a boron nitride particulate solid blended into the liquid metal alloy to form a paste. The paste is then combined with a quantity of a matrix forming flowable plastic resin such as microwax, silicone wax, or other silicone polymer to form the thermally conductive mechanically compliant pad, the compliant pad comprising from between about 10% and 90% of metal alloy coated particulate, balance flowable plastic resin.

Claims

1. A method of preparing thermally conductive mechanically compliant pads comprising the steps of:

(a) selecting a quantity of an indium containing alloy which has a melt temperature of between about 40°

C. and 120°

C.;

(b) treating said alloy to cause dispersal into divided form;

(c) combining said dispersed alloy with a compatible surface active agent and thermally conductive particles and blended to form a paste; and

(d) combining said dispersed alloy containing paste with a quantity of a flowable plastic resin material to form a thermally conductive mechanically compliant pad with said thermally conductive mechanically compliant pad comprising from between about 10% and 90% by volume of the combined dispersed metal alloy and thermally conductive particulate, balance flowable plastic resin.

2. The method of claim 1 wherein the particles making up said thermally conductive particulate solid have a diameter of between about 1 and 40 microns.

3. The method of claim 1 wherein said liquid alloy substantially encapsulates said thermally conductive particles to form a coating thereon, and wherein the liquid metal to thermally conductive particle volume ratio is at least 3:

1.

4. The method of claim 1 wherein said blended paste is further blended with microwax or silicone wax to form a conformable pad, with the pad comprising between about 10% and 90% by volume of homogeneous paste, balance microwax or silicone wax.

5. The method of claim 1 being particularly characterized in that said liquid metal alloy is in liquid state at temperatures above 60°

C.

6. The compliant thermally conductive pad prepared in accordance with the steps of claim 1.