Material Model and Simulation of Multilayer-AgSn-Foils for Transient-Liquid-Phase Bonding of Sensor Elements

Abstract

Thermo-mechanical deformation caused by the CTE-mismatch between device and substrate material is a severe problem for the mounting of sensor MEMS. FEM-simulations are helpful within the design process to minimize and predict errors of the output. Even when low-temperature interconnect methods like Transient-Liquid-Phase bonding are used simulations still might reduce costs in the development process. In this work, a material model for TLP-interconnects out of AgSn-alloys is presented. The elastic and plastic mechanical properties and CTE are determined for a temperature range between $25 ^ { \circ } \mathrm { C }$ and $200 ^{\circ}\mathrm {C}$. A combination of optical measurement for the strain, heating, and tensile testing was used for the experiments. Subsequently, the material data were used to analyze the thermo-mechanical behavior of a pressure sensor. On this example, the advantages of TLP-bonding were shown.