Three-dimensional FEM analysis of a hermetic seal ring design

The finite element method is applied to investigate the stress distribution of the seal ring/braze/substrate structures subjected to uniform thermal load in electronic packaging. A three-dimensional investigation is focused on the impact of the seal ring radius on the stress concentration at the corner of a rectangular hermetic package. Nine cases, each with a different seal ring radius, are evaluated in terms of the equivalent stress (Mises) and interfacial stress distributions on the brazing surface at both the seal ring and substrate sides. The investigation has concluded that stress concentration depends mainly on the ratio between the seal ring width, w, and the outer radius, R. An optimized design of the seal ring radius is suggested for the proposed model.