A ball grid array assembly includes a package cover that encapsulates a die and a portion of a substrate to which the die is attached, including an edge of the substrate. Encapsulation of the substrate edge by the cover reduces penetration of moisture or other contaminants into the substrate. The cover...http://www.google.com.hk/patents/US7091060?utm_source=gb-gplus-share專利 US7091060 - Circuit and substrate encapsulation methods
