CURVATURE BASED METRICS FOR INTEPRETING WARPAGE AND PREDICTING RELIABILITY IN SECOND LEVEL INTERCONNECTS

摘要

The authors in this paper have proposed a new methodology to predict curvature from depth data. This is a whole field methodology that measures curvature by the method of fitting surfaces through moving patches. Ability to estimate curvature and localized bend modes or shapes can help identify process defects like solder joint non-wets, shorting and also predict board flexure induced stresses in second level interconnects. This methodology has been demonstrated through synthetic range data as well as true experimental data. Authors in this paper have proposed methods to reduce the impact of noise, which is unavoidable in real measurements.