Vent blocking on vented ball grid arrays to provide a cleaner solution barrier

摘要

A vented BGA package is reconfigured by first applying a continuous bead of adhesive around the perimeter of the package to seal the gap between the lid and substrate. The continuous bead defines a channel through the pressure relief vents to a polarity through-hole in the lid. The BGA package is reflow soldered to a PWB at an elevated temperature using solder flux, clean or no-clean. The IC die achieves elevated temperature pressure relief through the pressure relief vents along the channel and out the polarity through-hole. After reflow a seal is applied to plug the polarity through-hole. The PWB is washed in an aqueous cleaner solution to remove flux residue. The continuous bead of adhesive and the seal form a cleaner solution barrier that prevents the solution from contacting conductors inside the package. The seal may be removed or left intact depending on the operating environment.