This Small Business Innovation Research (SBIR) Phase II project will further the development of lead-free transient liquid phase sintering (TLPS) adhesives with very high thermal and electrical conductivity for packaging high-power semiconductor devices. Conductive adhesives are typically used for low?]cost assembly, but these materials represent the weakest point in the thermal path. To address this issue, TLPS conductive adhesives form metallurgical bonds with the adherent metallization and can provide an order of magnitude or more improvement in thermal performance versus existing adhesive technologies. These low?]cost, lead-free materials are designed as drop?]in replacements for existing manufacturing processes. During this Phase II project, the focus will be the formulation, characterization, and qualification of lead-free TLPS adhesives for high-volume semiconductor device manufacturing. The primary objective of this project will be the demonstration of an order of magnitude improvement in effective thermal conductivity compared to commercial conductive adhesives for electronics packaging. Advanced characterization techniques, along with durability studies, will be instrumental for bringing these materials to a readiness level suitable for market penetration. The broader impact/commercial potential of this project is the development of new semiconductor die-attach materials suitable for the low-cost packaging of high-power semiconductor devices. A number of industries are aggressively developing innovative product lines centered on the concept of energy efficiency and higher performance; these include hybrid electric vehicles (HEVs) in the automotive sector, high-brightness light emitting diodes (HBLEDs) in commercial lighting, and concentrator photovoltaics (CPVs) for utility-scale electricity. Further, next-generation silicon devices, particularly those based on stacked-die architectures, also require improved conductive adhesives to fully enable their performance benefits. At present there exist no RoHS-compliant products that can satisfy all the needs identified by these markets in a cost-effective fashion. Yet these needs are becoming more urgent as a multitude of electronic devices reach the limits of today?fs heat dissipation technologies. The primary products which will result from this Phase II effort are advanced thermally and electrically conductive adhesives that can meet the thermal management requirements of advanced semiconductor packages while lowering their cost of manufacture
