The surface mount technology(SMT) has been widely utilized and replaced the previous pin-in-hole(PIH) method. In this study, a systematic way to determine the design criteria of the SMT from the predicted 3D solder joint profile is proposed. The solder joint profile is calculated using the available 3D FEM code which minimizes the system energy due to the surface tension and gravity. The FEM code is modified to extend its application to the gullwing type lead and leadless components. The design parameters are selected to be the solder volume, pad dimensions and lead location on pad. The solder joint profiles of QEP and SOP are calcualted for various design parameters, and acceptable ranges are derived. The Bond number in the acceptable range is also calculated. The results show that the length of pad is the most significant factor compared with the pad width and pad area.
