Gold-silicon fiber shorts in VLSI devices

An analysis and documentation method used to expose fibrous gold-silicon particle shorts was developed. The particles are a consequence of the die bond scrub-in being performed in an oxidizing atmosphere. Initially attached to the substrate, the fibers become detached during vibration or temperature cycling and cause intermittent shorts. It is shown that this particle generating tendency can be eliminated by using an adequate amount of cover gas concentration, which eliminates oxidation of the silicon. The bonding pressure, amplitude, duration, and temperature are other process parameters requiring optimization