ROOT CAUSE FAILURE ANALYSIS OF DENDRITE SHORTING: A COMPARISON OF ANALYTICAL TECHNIQUES

摘要

1. FTIR testing showed no difference organically on the surface of the dendrites from the coated reference area. No root cause for the failure could be determined by this analytical method for dendrite growth. 2. SEM and optical imaging showed the dendrite growth was on top of the coating and that the coating did not completely cover the solder mound, leaving the exposed metal to react within the environmental conditions. Optical imaging with UV light showed the exposed metallization of the solder domes was not covered by conformal coating. No root cause for the failure could be determined by this analytical method for dendrite growth, but it does show there is an open path for condensate to bridge pads. 3. EDS analysis showed the dendrites are comprised of tin, carbon and oxygen. There was not enough concentration to detect chlorine or sulfur elements. No root cause for the failure could be determined by this analytical method for dendrite growth.