ESD damage of GMR sensors at head stack assembly

Magnetic performance degradation of GMR sensors in magnetic recording heads often occurs after ESD exposure. This ESD damage phenomenon is not just limited to slider fabrication and head gimbal assembly (HGA) levels. It also can happen at head stack assembly (HSA) level. This study is to investigate ESD damage phenomena at HSA level under four types of experiments: Tribe-charge from insulating parts of HSA, EMI from external sources, direct charge, and AC field around HSA. The results indicate that the design and the connection of Flex Printed Circuit (FPC) has a significant impact on ESD protection for both HSA manufacturing and disk drive manufacturing.