Katsumi Miyama

Effects of external bending stress on device-embedded substrate

The displacement and stress-strain distribution of a device-embedded substrate under bending stress was simulated using the finite element method (FEM). In addition, the capacitance change of embedded devices was measured experimentally using an actual TEG substrate under bending stress. The results of the FEM analysis indicated that tensile stress at the surface of an embedded device may be a cause of electrical property changes. They may be affected by the substrate construction, especially the existence of a surface-mounted device. From the results of measuring the capacitance of an embedded chip capacitor with applied bending stress, the capacitance value increased relative to the stress. It was presumed that the distance between the electrodes of a laminated ceramic capacitor was narrowed slightly by the bending stress, which caused the capacitance increase.