Three-dimensional transient simulation of magnetoresistive head temperature during an ESD event

Abstract

Magnetoresistive (MR) heads for disc drives are susceptible to very low levels of ESD in the manufacturing and assembly process. The cost of failed heads and the ESD controls in the factories are high. One mode of failure is overheating of the MR sensor due to the ESD current. Knowledge of the head design parameters which affect the peak ESD temperature are desirable to guide the head design. The MR sensor temperature during an ESD event is modeled in three dimensions using finite elements. Results are given for the relative effect of ESD with a range of thermal and electrical properties, dimensions, and discharge time constants. The key parameters are the material properties of the sensor and insulator, the sensor height, and the insulator thickness. Lateral heat conduction reduces the temperature at the edges of the sensor.