A Study Of 0201’s And Tombstoning In Lead-Free Systems, Phase II Comparison Of Final Finishes And Solder Paste Formulations http://sheaengineering.com/Documents/APEX%2008%200201s%20and%20Tombstoning%20phase%202%20paper.pdf
CONCLUSION The conditions that were varied in this phase of the experiment were component type, padstack, paste volume, paste offset, placement offset, solder paste formulation and PWB final finish. Reflow profile and atmosphere were held constant: ramp profile and air environment. Only two of the four original pad stacks were used. The top four contributors to defect generation were component type, solder paste type, component orientation and padstack dimensions. Final finish was also a factor, with OSP producing 30% fewer defects than ENIG.
reply »