Sn whisker concern in IC packaging for high reliability application

In the study, the Ni underlayer plus matt Sn plated IC packaging of PLCC, PDIP and LQFP were subject to lead free (SAC) and SnPb surface mounting and wave soldering, respectively, then followed by TCT (-55degC to 85degC) 1000 cycle, THT (60degC /90%RH) 3000 hrs to investigate whisker growth propensity. The practical whisker performance confirmation on the PCB beyond reflow simulation and component level was concluded to understand the Sn whisker potential in term of Ni underlayer efficiency. Additionally, various Sn thickness over Ni layer in packaging level was also applied to explore the Sn thickness effect on the whisker growth over TCT. The Ni underlayer as Cu migration barrier to mitigate Sn whisker growth efficiency was concluded for high reliability application.