ESD Affected GMR Head Detection by Using Machine Model: Wavelet Transform Technique Approach

Abstract

This report proposes the wavelet transform technique using the 4th Daubechies order to detect glitches on a magnetic recording head signal in the time-domain. It is found that the glitch occurs when the electrostatic discharged (ESD) level of the machine model (MM) on giant magnetoresistive (GMR) heads is in the range of 6-9 V. The electrical test parameter and scanning electron microscope (SEM) photograph of recording heads shows no change in reader sensor. However, the parameter and SEM results clearly show the visible GMR damage when the MM-ESD voltage (VESD) is 10 V. The glitch in magnetic response signal of the GMR head occurs when the VESD is increased. Therefore, the wavelet transform technique can be a novel instrument to forecast the GMR degradation due to the MM-ESD effect.