Polymer Flip Chips with Extreme Temperature Stability in Space

The objective of the proposed SBIR Phase I program is to develop highly thermally and electrically conductive nanocomposites for space-based flip chips for performance over a wide service temperature range (-60 ?C to 400 ?C). Novel polyorganosiloxanes with controlled concentrations of pendent complexing moieties for metals, oxide-fillers, or nanotubes would be crosslinked to generate highly conductive elastomeric nanocomposite networks. NanoSonic has recently demonstrated electrical resistance of 0.1 Ohm through adhesively bonded polycarbonate substrates with a poly(organo-complexing)siloxane Ag composite. Low stress interfacial adhesives remain flexible under cryogenic conditions, effectively bond highly mismatched CTE substrates, offer superior corrosion resistance towards fuels, are impervious to UV and ozone degredation, and offer significantly greater adhesive strength over typical polysiloxanes. Polysiloxanes are an ideal candidate material for space systems yet have not been exploited to their full potential due to poor adhesion and the inability to evenly disperse polar conductive fillers (resulting in segregation and adverse insulating locales). The proposed poly(organo-complexing)siloxanes yield stable even dispersions with polar conductive fillers and would be developed during Phase II for microelectronics packaging on space platforms and with a major electronics company for microelectronics as an environmentally sound, low-cost replacements for current lead-based soldering systems.