ESD testing of head stack assemblies used in magnetic recording hard disk drives

Wallash, A.

doi:10.1109/eosesd.1999.819075

Cited by 9 publications

(4 citation statements)

References 6 publications

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“…The ESD test method used in this study is similar to the ESD gun testing at the HSA level [4]. ESD events were simulated up to 5 kV using a PESD 1600 (150 pF, 330 ) ESD gun.…”

Section: Methodsmentioning

confidence: 99%

“…In this kind of test, the ESD transient current is usually applied to the two reader pins (R+ and R-) and the ground plane (slider body or suspension) does not play an important role in affecting the ESD robustness of the MR head. On the other hand, there are several ESD test methods at the HSA level such Manuscript as tribo-charging from insulating parts of the HSA, ESD gun zapping at the actuator body or pins, electromagnetic interference (EMI) from external sources, and direct charging to suspension interconnect [2]- [4]. However, systematic studies on failure modes and their causes were not reported.…”

Section: Introductionmentioning

confidence: 98%

“…There are a lot of studies on the ESD damage of MR sensors. ESD tests can be performed at the slider level, the head gimbal assembly (HGA) level [1], the head stack assembly (HSA) level [2]- [4], or even at the hard disk drive (HDD) level [5].…”

Section: Introductionmentioning

confidence: 99%

“…Both head stacks are designed for recent models of 3.5-in desktop disk drives. In a method similar to [4], the head disk assemblies were stressed using an ESD gun at the pin connector of the HSA. There are several advantages of this ESD test method compared to other HSA-level test methods.…”

Section: Introductionmentioning

confidence: 99%

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Effects of the Suspension Interconnect on ESD Failures of the Head Stack Assemblies

Jang

Lee

2004

IEEE Trans. Magn.

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With increasing recording density and shrinking size of giant magnetoresistive (GMR) read/write heads, the GMR sensor is getting more sensitive to electrostatic discharge (ESD) events. In this study, two different types of head stack assembly (Type A and Type B) were studied in terms of ESD sensitivity. Both head stack assemblies (HSA) consist of head gimbal assemblies (HGA), preamplifier, E-block, flexible printed cable (FPC), voice coil motor (VCM) coil, and 20-pin connector for 3.5-in drive. Type A is a conventional HSA consisting of two or four HGAs with long tail suspensions whereas Type B is a head stack consisting of one HGA with FPC interconnect instead of a long tail. ESD events were simulated by zapping 20-pin connector with an ESD gun. A quasi-static tester (QST) was used for amplitude and resistance measurement of GMR heads after each ESD event. The test results showed that the failure voltage of Type B (1.0-1.2 kV) is much lower than Type A (4.0-5.0 kV). Furthermore, failed HSAs showed different failure modes: preamplifier damage for Type A and read sensor damage for Type B. To understand the main reason for low failure voltage for Type B, we investigated ESD sensitivity by modifying Type B with different interconnects, bonding methods, and arm actuator structures. These results indicate that the write-to-read crosstalk of interconnect (from preamplifier to head slider) during ESD events caused low failure voltage for Type B. It was found that the metallic structure surrounding the VCM coil is another cause for the low failure voltage of Type B.Index Terms-Crosstalk, electrostatic discharge (ESD), giant magnetoresistive (GMR), hard disk drive, interconnect, magnetic heads, preamplifier, slider.

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“…The ESD test method used in this study is similar to the ESD gun testing at the HSA level [4]. ESD events were simulated up to 5 kV using a PESD 1600 (150 pF, 330 ) ESD gun.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%