Analysis and Modeling of Thermo mechanical Deformations and Stresses in Redistribution Layers in the Fan-out Wafer Level Packaging

The paper describes the design of a temporary base for the integrated circuit dies placement used for the packaging operation at wafer level. In order to accurately predict the thermal deformation that would take place during the technological process, an analytical model has been devised to estimate the thermal deformation of the polyimide carrier. The level of deformation of the carrier and dies was determined through simulation of the structure in a finite element analysis environment. The difference in the values of the deformation of the die carrier when calculated by the analytical method and the finite element method turned out to be significant, but within the same order of magnitude. This indicates that the analytical calculation method can be used to quickly estimate the deformations occurring in the designed structure. However, when calculating the deformation of the dies themselves, this analytical method gives a significant error, which requires the development of a new analytical model.