Fast Qualification Using Thermal Shock Combined with Moisture Absorption

Abstract

Time to market is becoming one of the most important factors because of the fierce market competition. However, traditional reliability and interface toughness characterization tests take a very long time. For example, moisture sensitivity level assessment (MSL 1) will take 168 hours pre conditioning at 85C/85%RH and tradition thermal cycling takes even longer time. The long preconditioning times are chosen to ensure that also the thicker section of a package are completely saturated. Thinner packages, however, are already saturated after one to two days. In this study, we therefore investigated whether it would be possible to speed up the qualification process by shortening the preconditioning time. We focus in particular on the interface toughness. From our four point bending test and analysis, it is found that temperature has great effects on the interface toughness and moisture also has small effects on the interface toughness. In order to do the fast qualification test, thermal shock cycling tests combined with moisture absorption are performed. Experiments show that moisture can speed up the delamination.