SBIR-STTR Award

This Small BusinessTechnology Transfer Research (STTR) Phase I project seeks to advance the fundamental knowledge base and performance of lead-free electronic solders. Current lead-free electronic solders are performance limited by their thermomechanical fatigue and electrical characteristics due to microstructural instabilities, such as coarsening, grain boundary sliding, and ion migration along grain boundaries in these alloys. While nanoscale building blocks have been shown to alloy and provide enhanced properties in polymers, these tools have not been applied to control the dynamics of analogous structures in metals. An opportunity exists to utilize nanoscopic chemical reinforcement to control both microstructural stability and damage accumulation during service for lead-free electronic solder alloys. It is the objective of this project to utilize polyhedral oligomeric silsesquioxanes (POSS) to impart structural control at the 1-10 nm level in solders. Such control will afford solders with higher strength, durability, and dimensional stability for use as interconnects in aerospace, automotive, consumer and micro-electromechanical systems.The commercial application of this project is in improved, lead-free electronic solders. The identification of the mechanistic and process limitations for such control in alloys will afford insights into the development of solutions for metal fatigue, creep, and service life issues which plague commercial and military aircraft, automobiles, restorative dental amalgams and related prosthetics.

This Small Business Technology Transfer (STTR) Phase II project will develop nanostructured reinforcements to improve the thermo-mechanical fatigue (TMF) performance and service reliability of tin-based electronic solder alloys. Service reliability of solder joints will be studied under Phase II by simultaneously imposing external electrical, thermal and mechanical excursions under simulated realistic service conditions. Toward developing commercially viable products, Phase II will address scale-up issues in manufacturing different forms of nanostructured solder materials, as well as processing and disposal issues associated with the use of this product in fabrication of electronic components under different soldering methodologies, and in collaboration with solder suppliers and end users. A result of attempted adoption of lead-free solders has highlighted several adoption issues and concerns over service reliability of interconnects made with lead-free solder compositions. In Phase I, the general viability of incorporating surface active, and thermally stable nanostructured particulates as grain boundary reinforcements to significantly enhance mechanical and service performance and reliability of joints, was demonstrated. This fundamental discovery has significantly enhanced the understanding of the overall processes that affect the high temperature service performance and reliability of the solder joints. The proposed Phase II project will develop the knowledge base required for scale-up production of nanostructured solder materials and to obtain the technical data base necessary for implementation of the same in the manufacture of electronic components. The validation of nano-reinforcement of solders is expected to have significant commercial implications in a wide variety of structural materials. The proposed project represents an excellent step towards obtaining environmentally-benign solder materials with equivalent performance to traditional lead-tin, eutectic solders and which could lead to significant sales in the multi-billion dollar worldwide solder market.