Temperature and Process Dependent Material Characterization and Multiscale Stress Evolution Analysis for Performance and Reliability Management under Chip Package Interaction

Abstract

Abstract Distinct temperature and process dependent deformation behaviors under packaging temperature cycles are characterized for various packaging materials. Substrate and underfill deformations are described using Maxwell viscoelasticity model. Solder bump deformation is represented by incremental plasticity model. Anisotropic deformation in silicon and orthotropic deformation in substrate are also considered. The material deformation effects on stress evolutions during fabrication and under chip package interaction (CPI) are analyzed for a large package structure. Complex geometries spread over a large range of length scales are simulated using multi-level and multiscale sequential submodeling technique. Global package simulations show that substrate orthotropy has a significant impact on the package warpage during the assembly process. Sequential package assembly simulations are performed to examine the residual stresses at package, bump and interconnect scales. The results show that the package material behaviors during the assembly process affect not only the residual stresses in the large package structure but also in the local bump regions and the interconnect structures. The temperature dependent material non-linear behaviors under operating conditions also affect residual stresses and carrier mobility. This work demonstrates that developing performance and reliability management strategies under CPI should consider temperature and process dependent material deformations during fabrication and packaging.