Center for Advanced Life Cycle Engineering
University of Maryland
College Park, MD, USA
The ability to assess the life expectancy of solder interconnects in electronic assemblies is critical for determining the reliability of electronic equipment. While tin-silver-copper (SAC) solder with 3–4 percent silver content by weight has been examined and adopted extensively, low-silver and no-silver solders are being proposed and used for electronic assemblies. Of these solders, SN100C, a tin-copper-based solder, has gained acceptance particularly in wave solder applications due to copper dissolution issues associated with tin-silver-copper solders. However, the ability to predict lifetime performance is needed. This paper provides results from temperature cycling tests conducted over a variety of temperature ranges. Test results comparing no-silver SN100C with tin-silver-copper solder are presented. These results are used to derive models for predicting the life expectancy of no-silver SN100C solder. Regression analysis of test data is used to examine model form and derive model constants. Comparisons of estimates of time to failure using the derived models and results for additional tests are provided. The derived models allow for the estimation of temperature cycle–induced fatigue failure of solder interconnects under test and use conditions.
Complete article available to CALCE consortium members