Design considerations on solder joint reliability of dual row quad flat no-lead packages

The present studies are to determine the largest possible package body size and die size for dual row quad flat no-lead package feasibility designs by taking the warpage and solder joint board level reliability into consideration. The impacts of solder materials and lead finishing are also investigated. A three-dimensional finite element analysis is conducted to predict the solder joint creep behavior under a board level temperature cycling condition as defined in JEDEC specification. In order to model the solder joint structure in more detail without significantly increasing computational time, the global/local model approach is utilized. Since the first failure cycle for solder joint is of most interested during package development, the Coffin-Manson relationship between the first failure cycle and the incremental sectional-area averaged equivalent creep strain per temperature cycle simulated with finite element method is provided. The first failure cycle for solder joint can be then estimated with the Coffin-Manson fatigue life mode. Hence, the maximum package body size and die size can be optimized accordingly to suit application requirements.