NSF Award
0646556
This Small Business Technology Transfer (STTR) Phase II project builds upon the successful Phase I results to develop surface modified 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 reduced viscosity of BN/resin mixtures during processing so that increased BN filler particle loadings can be achieved, resulting in higher thermal conductivity electronic packages. These improvements are best realized using an ultra-thin (nm thick), conformal, pin-hole free, chemically bonded silica nanofilm selectively placed on the edges of primary BN platelets. Coating the edges of platelets only provides for a low cost impact since edges being nanocoated represent less than 10% of the available platelet surface area. Higher BN loadings in filled composites allow for improved heat dissipation in electronic packaging materials, particularly in the case of glob top coatings and potting compounds. Proposed Phase II R&D is focused on working with potential customers to develop applications of particle ALD surface modified BN fillers for their specific moulding compound systems. Film chemistry and thickness will be developed for their specific applications.<br/><br/>Commercially, the ALD nanocoating of individual ultrafine particles to control their surface<br/>chemistry is enabling technology that is unparalleled compared to more conventional CVD,<br/>PVD, PE-CVD, or wet chemistry solution processing. The process allows for individual<br/>ultra-fine particles to be nanocoated, rather than coating aggregates of ultra-fine particles. It<br/>is independent of line of sight and provides for chemically bonded films to the substrate<br/>particle surface. It is easily scalable. It is a forgiving process where the nanocoating<br/>thickness is controlled by self-limiting surface reactions (not flux, temperature, or time of<br/>processing like CVD, etc.). ALD films are pin-hole free and conformal. The potential<br/>impact of successful large scale processing extends far beyond this proposed<br/>microelectronics packaging application. It is now possible to produce<br/>ultrafine particles with designed electrical, magnetic, optical, mechanical, rheological, or<br/>other properties. Markets for such functionalized ultra-fine powders include<br/>microelectronics, defense, hardmetals, cosmetics, drug delivery, energetic materials, and<br/>polymer/ceramic nanocomposites, among others.
