Design and measurement of stress indicator structures for the characterization of Epoclad negative photo resist

摘要

Using new materials for the structural or active layers in MEMS requires the knowledge of the material properties. In this paper, the internal stress and the coefficient of thermal expansion of Epoclad negative photoresist are measured. Despite being a photoresist, the epoxy-based material has very good mechanical properties. It enables the creation of microscale mechanical structures using this material. The internal stress and the coefficient of thermal expansion were measured using on-wafer stress indicator structures. The structures were designed to give a response caused by internal stress measurable using an optical microscope. The coefficient of thermal expansion is measured via the internal stress at different temperatures.