|
|
|
   Mil PlasticFAILURE MECHANISMS OF PEMs AND HSMs
Appendix Table A1 lists the major package related failure mechanisms identified for both plastic and hermetic ICs. These mechanisms are sourced from both field return and reliability test data. The table shows that there are as many failure mechanisms for HSMs as there are for PEMs. Some mechanisms are common to both while others are unique to each package type. An important observation is that hermetic packages are more susceptible to mechanical stresses, whereas plastic packages are virtually immune to such stresses. Therefore, centrifuge, vibration, and impact shock are rarely, if ever, specified in the qualification of PEMs. However, there are three mechanisms unique to plastic packages, which warrant further discussion: moisture ingress, SMD package cracking, and thin film metal deformation/cracked passivation.
|
