A systematic study on the reliability of lead-free solder alternatives including Sn based microbump configurations and Cu based nanomaterials

The present work focuses on developing a systematic understanding of two challenges at the forefront of today's microelectronics assembly technology; 3D interconnects and solder alternatives. The first section of research focuses on investigating Sn-based microbump configurations (5.5mum-60mum), from a reliability standpoint. When dealing with joint dimensions on the micro level, Intermetallic Compound (IMC) formation and evolution are very different than in standard dimension joints. It is critical to understand IMC growth from a systematic perspective, focused on materials, experimental design and process optimization. Nanotechnology has enabled the development of a Copper nanoparticle paste (most particles <10nm) which can be processed at 200°C as a solder alternative using standard surface mount technologies. The second section of research focuses on understanding factors that impact the reliability of a nanoporous and nanocrystalline copper joint. Material properties such as shear strength, fatigue life, and creep values are investigated to further understand this unique material.