A novel decapsulation technique for failure analysis of epoxy molded IC packages with Cu wire bonds

A cost-effective and simple technique involved in the decapsulation technique of different packages with various epoxy molding compounds (EMCs) attracted a large interest for use in failure analysis of reverse engineering. In this study, we reported that the epoxies molded IC packages with Cu wire bonds were decapsulated using a mixed acid controlled by a jet etcher with minimum degradation of Cu wires and bond interfaces. It was found that the nitric acid to sulfuric acid ratio of 2:1 was the optimum recipe for the preservation of Al pad and Cu wire. We also successfully developed a process both including laser and wet treatments to solve the over-etching and corrosion problems for critical package geometries of ball grid array packages. Additionally, the various physicochemical properties of the wet etching rates for EMCs were also studied using an atomic force micro microscopy, a Kelvin probe force microscopy, and thermo-gravimetrical analyses.

► The decapsulation of EMCs can be achieved by acid etching and laser ablation. ► The increase of silica in EMCs can enhance the thermal stability of backbone. ► The wet etching rate of EMCs can be evaluated by their physicochemical properties.