NASA SBIR 2003 Solicitation


PROPOSAL NUMBER:03-S4.03-7773 (For NASA Use Only - Chron: 035234)
SUBTOPIC TITLE:Advanced Miniature and Microelectronics, Nanosensors, and Evolvable Hardware
PROPOSAL TITLE:Polymer Flip Chips with Extreme Temperature Stability in Space

SMALL BUSINESS CONCERN (Firm Name, Mail Address, City/State/Zip, Phone)
Nanosonic Inc
1485 South Main St
Blacksburg ,VA 24060 - 5556
(540) 953 - 1785

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Jennifer   Lalli
1485 South Main St
Blacksburg ,VA  24060 -5556
(540) 953 - 1785
U.S. Citizen or Legal Resident: Yes

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.

Potential NASA applications of the unique poly(organo-complexing)siloxane conductive nanocomposites range from polymer flip chips to conductive coatings, adhesives or sealants for thermal and power management of delicate microelectronic components in the spacecraft systems for increased service life spans. Resilient conductive nanocomposites are of great commercial interest for bonding substrates with large mismatches in coefficients of thermal expansion (CTE) or irregularly shaped substrates. Importantly, low modulus polyorganosiloxane elastomers can compensate for thermal expansion differences opposed to glassy epoxy or acrylate adhesives, while performing consistently over a wide service temperature range in extreme chemical and environmental conditions.

Several significant commercial examples of thermal management include microelectronic chips in miniaturized devices, cellular phones, hearing aids, microelectromechanical systems (MEMS), lab-on-a-chip and system-on-a-chip. IBM envisions the nanocomposites also as a potential replacement for all currently soldered microelectronic packages. Thermally conductive nanocomposites effectively dissipate heat away from delicate microelectronic components, thereby maximizing the service lifetime. The market for such an environmentally friendly and cost effective alternative to lead-based solders would eventually equal or surpass the market for current thermal management packages. Nonpolar polydimethylsiloxanes do not yield stable microcomposite dispersions; therefore novel functionalized polyorganosiloxanes will be exploited as high performance binding resins.