Effect of low-level ESD on the lifetime of GMR heads

This paper describes an experiment to address the issue of latent damage due to ESD. Controlled low level discharge from an ESD simulator was applied to GMR heads to produce slight damage. These heads were then subjected to overvoltage stress testing at elevated ambient temperature. The heads subjected to minor ESD show increased scattering of the signal amplitude change vs. time. Although the average lifetime at the same bias remains unaffected by the zapping, statistical analysis show a reduction in 95 % confidence lifetime due to the increased scattering of the data.