John Davis Bolt

Ceramic-fiber—Polymer composites for electronic substrates☆

Abstract Laminate composites of polymer resins reinforced by certain ceramic fibers exhibit a very favorable combination of properties for advanced microelectronic packaging applications. With proper design, these composites utilize the ease of processing and desirably low dielectric constants of polymers and the high thermal conductivity and dimensional stability of ceramics. Besides selecting appropriate material components, other key considerations in composite design include specifying (1) the directionality as well as magnitude for desired properties, and (2) the degree of component connectivity in various composite directions by controlling filler shape, orientation, loading, and processing. We report electrical and thermal properties of alumina-fiber—polyimide composites as a function of fiber loading, and show their agreement with predictions from theory. The inplane thermal conductivities and expansivities are dominated by the fiber whereas the out-of-plane dielectric constant is comparable with the polymer matrix. Faster, denser microelectronic devices are envisioned, combining the electrical performance of polymers with the thermal performance of ceramics.

Studies on Organoaluminum Precursors OP Aluminum Nitride Fibers

A melt-spinnable precursor of aluminum nitride fibers derived from triethylaluminum and ammonia contains AlNH, AlNH 2 groups, and a small number of AlN units characteristic of aluminum nitride. The molecular weight of a spinnable composition is 070, corresponding to an average molecular weight of 13 organoaluminum groups. Ammonia, a curing agent for the fibers, accelerates elimination of ethane from the material, and decreases its solubility in toluene.

Ceramic Fiber - Fluoropolymer Composites for Electronic Packaging Materials

Aluminum nitride (AIN), alumina and aramid fibers have been incorporated into epoxy and fluoropolymer matrices. The fluoropolymer composites have dielectric constants less than 3.4 and losses below 0.3%, measured out-of-plane. In-plane and out-of-plane thermal conductivities of the AIN-fluoropolymer composites averaged 5.2 and 1.3 W/mK, respectively, at fiber volume fractions of 0.26 to 0.29. In-plane thermal conductivities of woven fabric composites were accurately predicted by mixing rules; for non-woven and short fiber composites, thermal conductivities were less than predicted. These composites had higher out-of-plane thermal conductivities due to out-of-plane components of the fiber orientations.