A Review of Nanoporous Metals in Interconnects

Abstract

Interconnections in semiconductor devices need to provide a seamless electrical, thermal, and mechanical link to different parts of the circuit. Since the move away from lead-based solders due to toxicity concerns, the search has been on for materials that can provide desirable attributes before, during, and after bonding. While lead-free solders have been extensively used as a replacement, they are now reaching their limits in terms of pitch scaling, as well as, electrical and thermal properties, forcing the semiconductor industry to look for alternative material systems for the next interconnection node. This review provides an overview of key properties needed in metal interconnections and possible use of nanoporous metals due to ease of fabrication, nanostructured ligaments, and other key physical attributes.