Surface Mount Solder Attachment Reliability Figures of Merit -- 'Design For Reliability' Tools.

The design of high-reliability surface mount circuit products requires up-front attention to several critical design and assembly parameters. The Surface Mount Attachment Reliability Task Force has developed dimensionless solder attachment reliability Figures of Merit (FMs) that account for the primary factors determining long-term interconnection integrity. The FMs provide simply-applied relative measures of the reliability impact of a component or device/substrate assembly, and serve as a GO/NO-GO reliability decision tool for package, physical, and circuit designers. The FMs are an integral part of the "Design For Reliability" process at key product development stages. These design phases include component design and/or selection, component/substrate assembly design, and system design including thermal environment, product service life, and attachment reliability target. FM applications in attachment reliability evaluation are demonstrated through several examples based on the solder joint fatigue performance of thermally cycled leaded and leadless surface mounted devices.