Tribology of Textured Sliders in Near Contact Recording Situations

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Tribology of Textured Sliders in Near Contact
Recording Situations
Lin Zhou1, M. Beck2, H. H. Gatzen2, and Frank E.
Talke1
1 CMRR, University of California, San Diego,
USA 2 Institute for Microtechnology, Hannover
University, Germany
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Outline

• Background
• Proposal of textured slider
• Texturing method
• Evaluation of textured sliders
• Stiction/friction measurements
• Slider dynamics
• Steady flying status
• Contact start/stop (CSS)
• Lubricant redistribution on disk surface
• Summary

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Background

• To achieve flying height below 10 nm, super
  smooth disks are required
• Super smooth disks cause stiction
• Load/Unload technology or zone texturing are used

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Proposal of textured slider

• Reduce stiction by texturing slider rather than
  the disk

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Texturing method
Argon plasma etching Ion beam etching
Al2O3 crystals
Wear resistant coating
etching
coating
TiC crystals
Island-type texture created due to different
etching rate of different phases
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Slider samples
(Nominal flying height 7 nm _at_ 7200 rpm)
(Nominal flying height 5 nm _at_ 7200 rpm)
Original slider surface
Texture height 4.5 nm
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Disk samples
Disk M lubricant thickness 18 A data zone
Ra 0.35 nm landing zone bump height 10
nm Disk S lubricant thickness 20 A data
zone Ra 0.28 nm landing zone bump height
7.5 nm INSIC disk (batch IV) lubricant
thickness 12 A data zone Ra 0.20 nm
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Stiction/friction measurements during CSS
A typical CSS cycle
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disk M landing zone (bump height 10 nm)
(Nominal flying height 7 nm _at_ 7200 rpm)
stiction
7200 rpm
7200 rpm
stiction
Untextured slider
Textured slider
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disk M landing zone (bump height 10 nm)
(Nominal flying height 5 nm _at_ 7200 rpm)
7200 rpm
7200 rpm
stiction
stiction
Untextured slider
Textured slider
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Friction measurement at flying height 5 nm
On Disk M Bump height 10 nm
On Disk S Bump height 7.5 nm
In landing zone
In data zone
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Slider Dynamics
1. Steady flying status
LDV
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7200 rpm _at_ disk M landing zone (bump height 10
nm)
(Nominal flying height 7 nm _at_ 7200 rpm)
Slider bending mode
Untextured slider
Textured slider
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5400 rpm _at_ disk M landing zone (bump height 10
nm)
(Nominal flying height 7 nm _at_ 7200 rpm)
Slider bending mode
Slider torsion mode
Untextured slider
Textured slider
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7200 rpm _at_ disk M data zone
(Nominal flying height 7 nm _at_ 7200 rpm)
Untextured slider
Textured slider
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5400 rpm _at_ disk M data zone
(Nominal flying height 7 nm _at_ 7200 rpm)
Slider bending mode
Untextured slider
Textured slider
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Slider Dynamics
2. Contact start/stop (out-of-plane)
LDV
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INSIC slider (Flying height 7 nm)
untextured
On disk M Bump height 10 nm
On disk S Bump height 7.5 nm
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INSIC slider (Flying height 7 nm)
4.5 nm textured
On disk M Bump height 10 nm
On disk S Bump height 7.5 nm
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INSIC slider (Flying height 5 nm)
untextured
On disk M Bump height 10 nm
On disk S Bump height 7.5 nm
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INSIC slider (Flying height 5 nm)
4.5 nm textured
On disk M Bump height 10 nm
On disk S Bump height 7.5 nm
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Slider Dynamics
3. Contact start/stop (in-plane)
skew 10 degrees
LDV
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INSIC slider (Flying height 7 nm)
untextured
On disk M Bump height 10 nm
On disk S Bump height 7.5 nm
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INSIC slider (Flying height 7 nm)
4.5 nm textured
On disk M Bump height 10 nm
On disk S Bump height 7.5 nm
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INSIC slider (Flying height 5 nm)
untextured
On disk M Bump height 10 nm
On disk S Bump height 7.5 nm
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INSIC slider (Flying height 5 nm)
4.5 nm textured
On disk M Bump height 10 nm
On disk S Bump height 7.5 nm
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Lubricant redistribution on disk surface
Slider INSIC slider, FH 5 nm Disk INSIC
disk (batch 4), lubricant thickness 12 A
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After 5 min flying
3 mm
Untextured slider
45 degree
After 1 hour flying
After 5 hours flying
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After 5 min flying
3 mm
Textured slider (with 2.5 nm carbon overcoat)
45 degree
After 1 hour flying
After 5 hours flying
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After 5 min flying
3 mm
Textured slider (without overcoat)
45 degree
After 1 hour flying
After 5 hours flying
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(No Transcript)
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Right after testing
After 18 hours recover
degradation
After 1 week recover
Textured carbon coated slider
Textured uncoated slider
Original slider
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Removal mobile lubricant (with a Q-tip dipped in
HFE-7100)
Mobile lube thickness 2 A
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Wear track formed by textured slider without
overcoat
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Drag tests on bonded lubricant
After 5 min flying
After 1 hour flying
After 5 hours flying
Textured carbon coated slider
Textured uncoated slider
Original slider
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Textured uncoated slider
Original slider
Degradation
Textured carbon coated slider
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(No Transcript)
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Right after testing
degradation
After 18 hours recover
After 1 week recover
Textured carbon coated slider
Textured uncoated slider
Original slider
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Summary

• Textured coated sliders cause less lubricant
  depletion than untextured slider
• Textured uncoated sliders cause more lubricant
  depletion than textured coated slider
• Slight lubricant degradation was observed with
  the uncoated slider

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• Comment
• Textured sliders may be a possibility to avoid
  instability due to intermolecular forces if such
  an instability really exist.

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Future work

• Need to mask the read/write element during
  etching to evaluate manufacturability of textured
  sliders