Time-dependent microstructural and compositional changes at the interfaces between materials in electronics

摘要

Combined thermodynamic and kinetic models and concepts were presented for the better understanding, prediction and control of the time-dependent microstructural and compositional changes caused by diffusion, dissolution and chemical reaction processes at the interfaces between different materials. The chemical compatibility of the multitude of materials used in high-density electronics interconnections is increasingly important with decreasing solder volumes and thinner metallization layers, but needs also to be considered in the kinetically constrained local edge regions of the joints in conventional surface mount assemblies. The thermodynamic assessment of the joining or bonding system combined with the introduced qualitative kinetic understanding and models can indeed be used to improve the design and production of electronics devices. However, the presence of liquid phase, irregularities such as grain boundaries as well as the lack of kinetic and thermodynamic data and realistic kinetic software cause practical limitations to the extensive modelling concept.