The investigation of read layers damage during the electromagnetic curing process of head gimbal assembly

The investigation of the soft electrostatic discharge (ESD) event in which the magnetic polarity reversal of the pinning/pinned bilayers of a tunneling magnetoresistive (TMR) read head is randomly detected during the electromagnetic curing process of the head gimbal assembly (HGA) is carried out using a 3-dimensional (3D) simulation, followed by the experimental validation. It is found that the thermal radiation mechanism associated with radiative properties and physical structures of materials under exposure could largely be responsible for the damage. The important finding is that the average slider peak temperature, which presumably represents the average reader peak temperature, is much higher than that obtained from the chamber's thermocouple reading. The result is experimentally validated with only 4.6-6% difference.