Photo-dielectric polymers material characterizations for 3D packaging applications

When considering wafer level packaging (WLP) applications, the use of dielectric polymer materials becomes more relevant for reliability performance. Indeed, polymer materials can have excellent dielectric performances with a processability at lower thermal balance. Their mechanical properties also offer a better compliance between the silicon 3D stack and the organic substrate underneath, improving the overall Front-End / Back End compatibility. This study reports the thermo-mechanical behavior and properties evaluation of the most advanced photo-sensitive dielectric polymers with higher resolution available in the market. It will allow direct comparisons between different dielectric polymer materials with the focus of stress control and thermal stability. First part of the paper will present thermal and mechanical characterization of these polymers performed with the same experimental conditions. Second part will present the advantages and limitations of each measurement characterization technique. And finally, the most relevant characterizations will be extracted in order to compare such dielectric polymers for 3D packaging applications.