Investigating Stress in Hybrid Electronic Packages Using White Light Surface Profilometry

摘要

Hybrid electronic packages are often used in space applications because of their rigidity, hermeticity, and goodthermal dissipation properties. These properties make them highly reliable in the harsh space environment.However, a recent space application of hybrid electronic packages failed during testing. The failure was traced tocracks in the high temperature co-fired alumina ceramic substrates that resulted in the loss of electrical continuityin some packages. To investigate stress states and crack growth in the packages, a novel technique for stressdetermination using optical surface profilometry was developed. The technique employs a scanning white lightsurface profilometer to obtain topographical contour maps of the hybrid electronic packages. Surface curvaturereveals the stress state of a component, which can affect its functionality and reliability. By comparing thetopography during thermal cycling and de-processing of a fully assembled package, hypotheses regarding the buildupof stress can be investigated.