Thermal Interface Material with Mixed Aspect Ratio Particle Dispersions

Abstract

An electron package includes an interface member between an electronic component and a thermal dissipation member. The interface member is highly efficient in transmitting thermal energy and/or suppressing electromagnetic radiation, with a particle filler dispersion including a combination of substantially spherical particles and substantially platelet-shaped particles within dispersion attribute ranges.

What is claimed is: 
     
         1 . A thermal interface material positionable in proximity to a heat source for thermal dissipation from the heat source and for shielding of electromagnetic interference, said thermal interface material comprising:
 a polymer matrix; and   thermally conductive particulate filler dispersed in said polymer matrix at 30-50% by volume, said particulate filler including substantially spherical particles having an aspect ratio of between 0.8-1.2 and a spherical particle diameter, and platelet particles having a length, a width, and a thickness and a platelet particle diameter, wherein said length and said width are each substantially greater than said thickness, said platelet particles having an aspect ratio of at least 10, a volumetric loading ratio of said platelet particles to said spherical particles being between 0.1:1 and 1:1, and a particle diameter ratio of said platelet particle diameter to said spherical particle diameter being between 1:1 and 20:1,   wherein said thermal interface material exhibits a thermal conductivity of at least 0.5 W/m*K.   
     
     
         2 . A thermal interface material as in  claim 1  which exhibits an electromagnetic radiation absorption of at least 10 dB/in at 2.4 GHz. 
     
     
         3 . A thermal interface material as in  claim 1  wherein said particulate filler is dispersed in said polymer matrix at 40-50% by volume. 
     
     
         4 . A thermal interface material as in  claim 1  wherein said platelet particles have an aspect ratio of at least 100. 
     
     
         5 . A thermal interface material as in  claim 4  wherein said length and said width of said platelet particles are substantially equal. 
     
     
         6 . A thermal interface material as in  claim 1  wherein said spherical particles include alumina, and said platelet particles are selected from the group consisting of boron nitride, graphene, and combinations thereof. 
     
     
         7 . A thermal interface material as in  claim 6  wherein said polymer matrix is a thermoplastic elastomer. 
     
     
         8 . A thermal interface material as in  claim 1  which exhibits a compressive modulus of less than 5 MPa at 20° C. 
     
     
         9 . An electronic package, comprising:
 an electronic component;   a heat dissipation member; and   the thermal interface material of  claim 1  disposed between and in contact with said electronic component and said heat dissipation member.