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42 SMT Magazine • September 2016 For example, the 0603 chip is green for all processes at all confidence levels. That means that there is greater than 0.99 chance that a part will have the required <97% tin once soldered. On the other hand, the SSOP28-5.3 mm is col- ored yellow for process G at 60% confidence be- cause we expect a greater than 0.9 chance that a part will have <97% tin. At higher confidence levels, however, this part process combination turns orange because at higher confidence, it is more likely to be between 0.75 and 0.9 chance of having <97% tin. Although the higher con- fidence levels have lower probabilities of parts having <97% tin, generally the part-process combinations stay in the same category regard- less of confidence level. This suggests that the results are not being driven by a lack of sam- ple size. Conclusions The data clearly indicates that the prob- ability for self-mitigation is strongly depen- Table 4. Self-mitigation probabilities with 60% confidence. Table 5. Self-mitigation probabilities with 80% confidence. MITIGATION OF PURE TIN RISK BY TIN-LEAD SMT REFLOW