Characterization of Moisture Uptake in Microelectronics Packaging Materials

Moisture uptake of materials, used in optoelectronic sensor packaging for the purpose of component attach or for encapsulation, is investigated. The diffusion behavior of these mostly epoxide-based polymer compounds is characterized under various temperature and humidity loads and described using analytical models. The water uptake during soak tests was determined and the data can be fit assuming multistep diffusion behavior. It is assumed that this behavior can be assigned to the formation of hydrogen bonds and moisture absorption in the free volume of the polymer matrix [1]. To investigate this assumption further, in addition to gravimetric methods, the evolution of the O-H stretch modes are measured by Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR).