Most semiconductor devices are now packaged in an epoxy polymer composite, which includes silica powder filler for reducing the thermal expansion coefficient. However, increased heat output from near‐future semiconductors will require higher thermal conductivity fillers such as aluminum nitride (AlN) powder, instead of silica. Dispersant chemistry is applied, in order to achieve a high volume percentage of AlN powder in epoxy without causing excessive viscosity before the epoxy monomer is crosslinked, thereby increasing the thermal conductivity of the composite. In the preliminary experiment, high solids loading, up to 57 vol%, was achieved with a wide particle size distribution, and the viscosity of that dispersion was 60 000 to 90 000 cps, resulting in easy flow by gravity alone at room temperature. The highest thermal conductivity of the composites measured by the hot‐disk method was 3.39 W/mK, which is approximately 15 times higher than pure epoxy. The Agari and Uno model was a good fit to the experimental data. Electronic I–V curves obtained after encapsulation of testing devices indicated that the highly AlN‐filled epoxy slip appeared to be feasible for use in the encapsulation of integrated circuit chips.

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A new binder formulation has been developed for Fused Deposition of Ceramics (FDC) which consists of commercially-available polymer constituents.. This formulation was used. in conjunction with lead zirconate titanate (PZT) and hydroxyapatite (HAp) powders. Adsorption studies were performed to test the effectiveness of several carboxylic acids and alcohols on the dispersion of these powders in the binder system. In both cases, it was found that stearic acid was most effective as a dispersant for the ceramic powder / thermoplastic system. After a suitable dispersant was chosen, ceramic powders were compounded with the binder formulation to yield 55 vol.% ceramic-loaded materials. The resultant compound was• used to make filament suitable for use in a modified StratasysTM 3D-Modeler. The filament was well suited for FDC usage, and the parts made using FDC contained no detectable filament-related defects.

Self-diffusion data are collected from tlhe literature in an attempt to better understand the strong effects of carbon as a sintering aid in SIC. These data indicate that the presence of excess carbon, in addition to reduciing the native S O 2 layer of the Sic, probably enhances the ralte-controlling bulk self-diffusion rate of Sic by a factor of about 100. [