Adhesion features of bonded interfaces interpreted by Taguchi technique

With the increasing applications of flip-chip technology in the microelectronics industry, the adhesion strength of interfaces in the flip-chip microelectronic structures has become an important issue for manufacturing and operation. The existence of defects in the corresponding interfaces can gradually degrade the interfacial adhesion when the package is exposed to the high temperature and humidity. The effects of IC package with different solder mask thickness under different temperature and relative humidity environment conditions on the adhesion strength were studied. The control parameters are environmental temperature, relative humidity, soaking moisture time and solder mask thickness. The interfacial adhesion strength was obtained by using a dynamically material testing system (MTS 810) with a set of special testing jig. Analysis of variance (ANOVA) is the statistic method used to interpret these experimental data. Taguchi technique with ANOVA is used in this paper. The significant variables (factors) can be checked from Taguchi techniques, which indicate a very good fit to the estimated regression equation for the moisture weight gain and the interfacial adhesion strength. The research results are helpful to identify improvements required in the adhesion performance of underfill/solder mask/substrate interface.