J. E. Klein, L. A. Copeland, Texas Instruments, Tucson, AZ

Summary: Copper wire is beginning to replace gold as the standard electrical connection from the silicon die to the package leadframe. In order to characterize or perform failure analysis on these devices, the plastic molding compound must be removed, but without compromising the copper wire or copper bonding surfaces. Utilizing a 1064nm NdYAG lamp pumped marking laser along with unique mixes of fuming sulfuric acid and nitric acid, reproducible decapsulation of copper bonded devices without damage to the wires, packaging material, or to the silicon die circuitry itself can be achieved.