ESD damage by arcing near GMR heads

This paper reports the ESD damage of GMR heads in gold ball bonding process (GBB), which utilizes a high voltage arc to form a gold ball, then ultrasonically bonds two adjacent pads. An ESD failure model of transient current damage, different from those previously reported on directly arcing to GMR or due to EMI, is described and explained by device charge-up due to nearby arc, and successive discharge event. GMR heads suffer serious damage when an oxidized layer forms on the wand surface, resulting in typical arc point shift.