The Effect of Cavities and Channels on the Strength of LTCC Substrate

The effect of cavities and channels on the strength of LTCC substrate has been investigated by finite element analysis with commercial software ANSYS. The simulation model is based on three-point bending test of thick film LTCC substrate. Axial tensile stress and shear stress among layers are characterized to describe the effect on flexural strength and inter-layer shear strength. X, Y-axial channels, Z-axial via-hole, and cavities of various amounts are formed in the middle or surface layers of the LTCC substrate. The simulation results show that the maximum tensile stress always appears on the midline of the substrate bottom and causes fracture. The shear stress concentration has been found on the sidewalls of the holes and cavities and enhances the interlayer stripping.