Stress analysis of metal seal ring AlN packages

The static response of the molybdenum/AlN seal ring structure, subjected to uniform cooling (or heating), is evaluated by finite-element analysis, and results are compared with those of the widely used Kovar/Al₂O₃ combination. Results have shown that within the main portion of the seal ring structure (0⩽x⩽0.85l), shear stress and transverse stress are close to zero and can be neglected when compared to the level of longitudinal stress. However, near the ends, the shear stress and transverse stress can no longer be neglected, and the complicated stress distribution at the end area has far exceeded the results of classical bending theory, especially for the non-zero transverse stress