Effect of Printed Circuit Board Design Parameters on Solder Joint Reliability for Memory Packages

Electronic packages are susceptible to solder joint failure arising from thermal strain mismatch and thermo-mechanical stresses during thermal cycling conditions. The performance of the overall system through temperature cycling stresses is determined not only by the individual attributes of a component, such as die and substrate on BGAs (ball grid array), but also those of the system PCB (printed circuit board). System level mechanical and electrical requirements should be considered when defining component layout, PCB thickness/materials and the use of underfill. In addition, matching the pad design of the system PCB to that of the component plays an important role in the Temperature Cycling (TC) response of the system. This work utilizes methods of simulation and test validation to understand the effects of PCB design considerations on the robustness of the overall system. Various parameters including pad size, pad ratio, pad type, PCB CTE (coefficient of thermal expansion), PCB modulus, and mixed pad distribution were studied for their impact.