STTR Phase I: Improved Boron Nitride Materials for Enhanced Thermal Management

This Small Business Technology Transfer Phase I project provides for the manufactureof improved boron nitride (BN) filler materials for electronic thermal management applications. Novel Atomic Layer Deposition (ALD) nanocoating is used to selectively functionalize edges only or edges/basal planes to improve wetting of BN platelets with resin encapsulants. The improved wetting allows for significantly reduced viscosity (~ 5 times less) of BN/resin mixtures during processing and improved interfacial adhesion in the cured composite. These improvements are realized using an ultra-thin (nm thick), conformal, pin-hole free, chemically bonded alumina nanofilm on individual BN platelets that provides for an improvement in rheological properties without a significant reduction in thermal conductivity. Hence, higher BN loadings in filled composites will allow for significantly improved heat dissipation in electronic packaging materials, particularly in the case of glob top coatings and potting compounds. Individual fine sized BN platelet particles will be selectively nanocoated (edges only or edges/basal planes) with chemically bonded Al2O3 films of ~50, 25, 12.5, 6.3, 3.2, 1.6, and 0.8 nanometer thickness. The nanocoated BN will be blended at a 40 volume % loading in a liquid encapsulant mixture (will measure viscosity), cured, and tested for thermal conductivity and peel strength. Commercially this addresses one of the most pressing problems in the electronics industry, namely the heat dissipation required by the use of faster and more powerful chips. Since boron nitride has one of the best thermal conductivities as a filler, any improvement in its performance can positively address this problem. Furthermore the potential impact of successful large scale processing extends far beyond this proposed microelectronics packaging application. Nanoscience will only achieve true "disruptive" technology status if the individual surfaces of ultrafine particles can be functionalized. ALD nanocoating of ultrafine particles provides such an opportunity. It is now possible to produce ultrafine particles with designed electrical, magnetic, optical, mechanical, rheological, or other properties. Markets for such functionalized ultra-fine powders include microelectronics, defense, hard metals, cosmetics, drug delivery, energetic materials, and polymer/ceramic nanocomposites, among others. A better understanding of the nanocoating of ultra-fine particles and its cost/performance value will be developed.