Study of the use of the Weibull distribution and compliance of the reliability of lead-free solder in accelerated thermal cycling through varying solder volume, pitch, and thermal range with previously established materials models.

摘要

The research presented addresses the reliability of lead-free solder in accelerated thermal cycling to reevaluate the use of the two-parameter Weibull distribution and to better understand the affects of changing solder joint volume, distances to neutral point, and thermal cycling temperature ranges. 10mil, 12mil, and 16mil diameter Sn96.5Ag3.0Cu 0.5 solder volumes are compared along with five distances to neutral points and three thermal cycling ranges to find their relationships and reliability during thermal cycling. The results of statistical tests and post-failure analyses are compared to popular reliability models to show discrepancies between them and the experimental results. These comparisons demonstrate that many studies do not correctly use the Weibull distribution as they do not include the shape parameter as an integral part of their analyses. 10mil components perform best at equivalent strain ranges. 12mil components undergo an unusual shift in reliability depending on the strain. 16mil components follow normal trends.