Evaluation of tribocharging and ESD protection schemes on GMR magnetic recording heads during CO2 jet cleaning

Abstract

This paper presents the results of investigations into tribocharging and ESD effects of CO/sub 2/ snow jet cleaning on magnetic recording components for hard disk drives. The studies are performed at different levels of integration, including component parts, head gimbal assembly (HGA) and head stack assembly. The electrical stresses induced during the cleaning process are evaluated, followed by investigation of the effectiveness of traditional ESD protection schemes. CO/sub 2/ snow jet cleaning uses specially designed nozzles to expand liquid CO/sub 2/ into a two-phase flow. The jet stream consists of a high-density jet of solid, yet soft, CO/sub 2/ particles ('snow') immersed in a CO/sub 2/ gas. The tribocharging effect of the high velocity impact of the CO/sub 2/ particles on the surfaces of the slider, suspension, flex cable, and e-block components and assemblies is studied. This paper also includes results of process design variations, such as grounding and ionization to reduce the risk of ESD damage. A quasistatic tester was used to characterize the HGAs and HSA before and after cleaning.