A Three-Dimensional Solder Shape Model Incorporating Top Pad Inclination and Misalignment

Abstract

In this technical brief, we describe a simple, yet versatile solder shape prediction model that can handle inclination (as is likely to occur when warped substrates are used) and misalignment of the top pad of the solder joint relative to the bottom pad. The developed model is general in nature and is demonstrated on a solder joint with circular top and bottom pads and on a stud joint where the interconnection is to a stud on which the wetted area is to be determined through simulation. The model was able to accurately predict the solder profiles from literature with an error of ±5%. A program written within the MATHEMATICA ® environment was developed and used for the above simulations.