Novel electrical re-connection of very thin fine pitch ball grid array (VFBGA) package for advanced backside fault isolation

With the development of the semiconductor industry, the layers of metal interconnection have increased, and the front-side package dimensions have shrunk. All these trends emphasize the importance of backside fault isolation (FI) in advanced product failure analysis (FA). However, electrical signal re-connection when handling the repackage becomes the primary challenge in handling backside FA. An innovative method for electrical re-connection, which can be effectively applied to the very thin fine pitch ball grid array (VFBGA) package for backside FI, is introduced. By engraving a pattern (for example holes, blocks and trenches) on the surface of the package, and depositing metal into the pattern, electrical signals can be re-connected out from bond pads to metal blocks on the package surface through metal lines embedded in the pattern. Detailed processes, operating parameters and experimental results are represented.