31 December 2010 Clearance measurement of commercial slider/disk with a symmetrical common-path heterodyne interferometry
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Proceedings Volume 7544, Sixth International Symposium on Precision Engineering Measurements and Instrumentation; 75444Z (2010) https://doi.org/10.1117/12.885916
Event: Sixth International Symposium on Precision Engineering Measurements and Instrumentation, 2010, Hangzhou, China
Abstract
Slider/disk clearance, also known as flying height, is one of the most critical parameters when designing a hard disk drive (HDD). Flying height is supposed to be lower and lower with the increase of magnetic recording areal density in order to maintain sufficient signal amplitude and hence high signal-to-noise. In this paper, a symmetrical common-path heterodyne interferometry (SCPHI) is introduced and utilized to measure the clearance of commercial slider/disk. A high-speed phase measurement technology is employed and the symmetrical common-path configuration can effectively compensate the errors induced by spinning disk distortion, disk runout and some environment disturbances. Theoretical analysis indicates the resolution of SCPHI is better than 0.1 nm when the resolution of phase measurement is 0.10. On the other hand, the method was employed to measure the height of an etched groove, and the results agree well with these by a commercial white light interferometric surface profiler, verifying its sub-nanometer resolution. Furthermore, clearances of commercial slider/disk interface under different rotation speeds were successfully obtained by the proposed method.
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Nanhai Song, Nanhai Song, Yonggang Meng, Yonggang Meng, } "Clearance measurement of commercial slider/disk with a symmetrical common-path heterodyne interferometry", Proc. SPIE 7544, Sixth International Symposium on Precision Engineering Measurements and Instrumentation, 75444Z (31 December 2010); doi: 10.1117/12.885916; https://doi.org/10.1117/12.885916
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