Applied FEM techniques in ceramic feedthru package design

With the advent of high power GaAs MMIC devices, hermetic feedthru microelectronic packages have become increasingly more important in aerospace applications. Critical to the design of this product, is the thermal expansion mismatch that takes place during brazing between package components. This thermal expansion mismatch produces high residual stresses in the alumina feedthru that, depending on the severity, can lead to premature component failure. In the present work, ANSYS™ finite element method software has been coupled with CARES/Life failure probability design software to quantitatively determine the reliability of this package.