Improvement of redeposition removal from hard disk head etched by reactive ion etching

Abstract

As the feature size of read-write head devices becomes smaller, the removal of the post-etch residue, redeposition, at etched sidewall becomes a critical issue in the fabrication of read-write head fabrication due to the significant increase in etching time which causes the increase in redeposition formation. However, cleaning with alkaline base solution, sodium hydroxide, is one of method due to its advantages of high cleaning efficiency, low operation cost, easiness and safety to handle, soft chemistry, and requiring no special or expensive equipment. In this research, the effect of sodium hydroxide concentration and the scrubbing time are investigated. For the experimental results, it could be clearly that the cleanliness of etched sidewall is dependent upon these parameters. With high sodium hydroxide concentration and long scrubbing time give more cleaning efficiency. In other hand, pitting defect can be created. The best cleaning condition which provides best cleanliness is 0.05% sodium hydroxide and scrubbing time of 12 minutes. When compared with the outcome of new cleaning condition and current condition, 0.02% sodium hydroxide and scrubbing time of 4 minutes should result in the best in sidewall cleanliness which are confirmed by SEM and AFM analyses and fluoride ions measurement by Ion Chromatography. Moreover, the better electrical performance and failure rate due to cleanliness improvement are also obtained.