Degradation of Leadfree Solder Materials Subjected to Isothermal Aging with Use of the CABGA208 Package

Abstract

Electronic products are continuing to improve and evolve with new and innovative packaging technology. With these advancements and the legislation banning SnPb, the reliability of lead-free solder materials has become a high priority. When considering the effects of isothermal aging on the relative reliability of various electronic packages, the data indicates packages will show various decreased levels of reliability as aging is increased. The most commonly used lead-free solder, SAC305, has shown increased levels of reliability compared to SnPb, but as the solder material is aged, the reliability begins to degrade at an exceedingly high rate when compared with other materials. Multiple lead-free solder materials with various combinations of metals have been examined to provide a solution for this high degradation rate. This paper examines the degradation rate as aging time is increased in multiple lead-free solder materials combined with the CABGA208 package when subjected to multiple test conditions. The CABGA208 package is an excellent example of this trend based on the level of failure throughout the various test and the rate of degradation. For each test performed, the CABGA208 package exhibited high failure rates with most test groups having 100% failure. The testing method includes thermal cycling between −40°C to 125°C. A comparison between 0-month (no aging) and 24-month aging was performed to measure the reliability of the solder joints using degradation plots through use of Weibull analysis. Results show a systemic adverse effect of aging time on package level reliability in multiple harsh environments.