Browse Prior Art Database

Method for Producing Micron Sized Asperity Bumps on Disks

IP.com Disclosure Number: IPCOM000112362D
Original Publication Date: 1994-May-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Khanna, VD: AUTHOR [+4]

Abstract

Several methods for producing micron sized bumps on magnetic recording hard disks are identified. All methods use a laser to define the height, size, and geometry of the bumps.

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Method for Producing Micron Sized Asperity Bumps on Disks

      Several methods for producing micron sized bumps on magnetic
recording hard disks are identified.  All methods use a laser to
define the height, size, and geometry of the bumps.

      It is generally necessary to test magnetic recording hard disks
for irregularities in their surface contour.  In order to achieve
this, a calibrated glide head or slider must be flown over each disk
to determine that any surface irregularities are below a set value.
This procedure requires calibrating the slider on a calibration disk
with known small asperities.  The asperities should have an
approximately gaussian contour in the direction parallel to the disk
circumference.

      Suggested are several unique methods for making these bumps,
sub-micron in height, several microns in length in the plane of the
disk.  The first consists of laser enhanced exchange plating using a
focused laser beam directed through an electrolytic solution covering
the disk.  For a copper coated disk submerged in copper sulfate
solution, exchange plating will cause maskless selective plating in
the form of bumps to occur after a few  seconds of laser dwell time
in the region of the absorbed laser radiation on the disk.  At higher
laser intensities, small holes (craters) can be made in the disk
resulting in a surrounding circumferential bump by way of laser
melting.  Metallic nickel bumps can be deposited via laser enhanced
electro...