Reduction of voiding in eutectic ball grid array solder joints

Abstract

The rapid progress of ball grid array (BGA) component technology has served to alleviate many problems associated with the placement and soldering of high lead count, fine pitch surface mount technology (SMT) packages. An unfortunate result of this process, however, is the occurrence of voids in the interconnecting eutectic solder balls of these packages. Large voids can affect the mechanical and thermal properties of the interconnect, which can reduce a component’s mean time‐to‐failure and may also affect the transmission of high frequency electrical signals through the solder ball. For this reason, several experiments were conducted to investigate the manner and mechanisms in which voids are introduced into eutectic BGA solder ball joints. The following process parameters were found to be the primary parameters responsible for the voiding phenomenon: condition of the component’s alloy and substrate, oxygen concentration in the reflow atmosphere, solder paste properties and the reflow profile. Through modification and optimization of process parameters in the manufacturing environment, BGA solder joint voiding was greatly reduced.