Computational modeling of direct molten solder delivery for ball grid array applications

摘要

Computational modeling has been performed to determine optimum operational parameters for a piston-driven molten solder jetting device used to create array interconnects for BGA applications. The device is capable of delivering a 20 x 20 array of 600-800 (mu)m diameter molten 60Sn40Pb solder droplets onto an array of copper pads and primarily consists of an electromechanically driven piston, a heated reservoir, and an orifice plate. computer simulations were performed to determine the relationship between the amplitude and the rate of piston displacement, the onset of fluid ''pinch off'', and the production of satellite droplets. Results show that stable droplets are generated when the volume of the displaced fluid has a spherical diameter that is approximately equal to the orifice diameter.