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Adjusting Laser Texture Bump Height by Controlling the Oxygen Content of Ambient Atmosphere during Texturing

IP.com Disclosure Number: IPCOM000117795D
Original Publication Date: 1996-Jun-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Baumgart, P: AUTHOR [+3]

Abstract

Laser texturing of Ni-P coated disk substrates for magnetic recording has been introduced. In this process, a pulsed laser creates a landing zone at the disk's inner diameter consisting of distinct protrusions or 'bumps' extending above the original smooth disk surface by ca. 20-50 nm. It is important to control this height since it affects the tribological performance of the disk drive. It must be sufficiently high to eliminate excessive slider-disk stiction, but low enough to be compatible with the fly height of the slider used, since excessive interference between bumps and slider can lead to a wear failure. Controlling the oxygen content of the ambient atmosphere during texturing provides a simple way for fine tuning of bump heights (*).

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Adjusting Laser Texture Bump Height by Controlling the Oxygen Content
of Ambient Atmosphere during Texturing

      Laser texturing of Ni-P coated disk substrates for magnetic
recording has been introduced.  In this process, a pulsed laser
creates a landing zone at the disk's inner diameter consisting of
distinct protrusions or 'bumps' extending above the original smooth
disk surface by ca. 20-50 nm.  It is important to control this
height since it affects the tribological performance of the disk
drive.  It must be sufficiently high to eliminate excessive
slider-disk stiction, but low enough to be compatible with the fly
height of the slider used, since excessive interference between bumps
and slider can  lead to a wear failure.  Controlling the oxygen
content of the ambient  atmosphere during texturing provides a simple
way for fine tuning of bump heights (*).

      Laser texture experiments have been performed using atmospheres
of different gases around the laser focus on the disk.  The gases
tried were: He, Ar, N2, CO2, clean dry air (CDA), O2, and ambient
air.  Experiments in vacuum were also performed.  It was discovered
that a bump height of e.g., 40 nm in ambient air for an optimized
laser pulse energy could be increased by ca.  10 nm when eliminating
oxygen from the ambient atmosphere, independent of which oxygen-free
gas was used from the list given above.  The same effect was observed
in vacuum.  On the other hand, when gradually increasing the...