A failure analysis process flow development for a board mount plastic BGA multichip module is described. Both front and backside approaches are investigated. Following the probing (at both front and backside), front side chemical de-cap procedure is also developed to expose the components without disturbance. The development of this failure analysis process flow has successfully isolated defective IC dice, identified a die attach interface corrosion mechanism, and assembly related die top mechanical defects. This process can be adopted to failure analysis for other plastic BGA modules.