Migrated copper resistive shorts in plastic encapsulated devices

Abstract

Summary form only given. Integrated-circuit devices using the Al-Cu bond pad systems may be subjected to failure mechanisms based on electrolytic corrosion. The migratory copper resistive short (MCRS) failure mode is one example of this mechanism and results in the formation of filamentary or dendritic deposits of copper between adjacent bond pads on the IC chip. Such a failure mode was identified in the plastic encapsulated ECL devices. A number of advanced analytical techniques have been applied in order to characterize the failure mechanism. These techniques included environmental scanning electron microscopy (ESEM), energy dispersive X-ray spectroscopy (EDX) and c-mode scanning acoustic microscopy (C-SAM). A model, based on the physics of condensation, ionic migration and thermally activated mechanism, was developed, and verified with the field returned failure data. The source of moisture, copper and ionic contaminants that accelerate the failure mechanism were also discussed.