Nanoparticles sintering technology for power electronics modules and beyond

Abstract

IN advancing the ’More thanMoore’ paradigm, heterogeneous integration has emerged to facilitate the creation of highly efficient, compact, and multi-functional semiconductor systems. Addressing the challenges related to power efficiency, superior performance, and integration density, low-temperature nanoparticle sintering technology has become pivotal for integrating diverse materials and components in advanced semiconductor packaging. Traditional electronic packaging materials face limitations and process complexity, making low-temperature nanoparticle sintering an attractive option. With its benefits of low processing temperatures (< 0.4 Tm), exceptional electro-thermomechanical performance, and high process flexibility, this technology is gaining increasing attention, particularly in high-power electronics packaging applications. Over the past decade, silver (Ag) sintering technology has shown promise in the power electronics industry, serving as an effective solution for high-power die-attach. However, due to the high cost of materials, efforts have been directed towards pressure reduction and exploring alternative sinter materials to reduce overall process costs. In recent years, the concept of ’all copper (Cu) interconnect’ has transcended fromlow-power to high-power applications, with low-temperature Cu nanoparticle sintering showing substantial potential as a replacement for Ag in pressure-assisted sintering. Despite this promising avenue, the understanding of sintered Cu materials remains limited, primarily due to susceptibility to oxidation issues. Comprehensive studies comparing both sinter materials, extending beyond mere shear tests, are insufficient, leaving a significant gap in our understanding. Furthermore, methodologies for characterizing the sintered structure and providing detailed insights into its thermo-mechanical behavior are notably absent. In this dissertation, molecular dynamics (MD) simulation was employed at first to study the nanoparticles’ coalescence kinetics and mechanical and chemical performance of coalesced nanoparticles. A two-hemispherical nanoparticle model was built to simulate the impact of sintering temperature and pressure on low-temperature pressureassisted coalescence. The sintering dynamics and microstructure evolution were analyzed, including neck growth, shrinkage variation, grain boundary development, and dislocation activities. Furthermore, on the basics of pressure-assisted sintered nanoparticles, uniaxial tensile tests with a constant strain rate were employed to investigate its tensile performance. Subsequently, another mechanical nanoindentation simulation was implemented in a multi-nanoparticle sintered structure. The impact of indentation position and indenter size on the nanoindentation response was investigated. At the end of the first chapter, the chemical corrosion of sulphidation on multi-Ag nanoparticles’ sintered structure was simulated by the reactive-force-field (ReaxFF) MD method. The sulphidation on the dense Ag and porous sintered structures was compared and analyzed. Moreover, the sulphidation mechanism was revealed at an atomic level...Electronic Components, Technology and Material