ENE692
LECTURE 4_2
HGA Technology
1
Basic HGA Technology
• HGA assembly process
• HGA process control
• Suspension design and function
• Slider design and function
2
HGA Assembly process
3
Typical HGA process flow
4
HGA mechanical controls
5
HGA alignment
6
HGA pre-load
7
Motivations from Gram load adjustment
• Increasing Magnetic Recording Density requires lower and
tighter flying height distribution.
• Suspension Preload is a significant contributor to the flying
height. Even more important for femto sliders.
• HGA (Head Gimble Assembly) and HSA (Head Stack
Assembly) processes can produce significant shift of the mean
and sigma of gram load and flying height.
• Gram load adjust can be used to compensate for the deviations
caused by crown, camber, etch depths, PSA, stacking tolerances
etc. on the flying heights.
8
Motivations from Gram load adjustment
Crown (C) is the maximum separation between the cylindrical contour
along the flying direction and an imaginary plane drawn between leading
and trailing edges of the ABS.
Camber has a similar definition in the perpendicular direction
between the two sides of the slider.
9
How does the gram load adjustment work?
10
HGA PSA/RSA
11
Gimbal bond strength
12
Fly Height
13
Fly Height
14
Impact of contamination
15
Suspension design and function
16
Gimbal strength testing
17
Stress due to buckling and pitch
18
Slider components
19
Slider components
• Air bearing
• Read/Write circuit
• Trailing edge
• Leading edge
20
Air bearing/fly model
21
Fly height history
22
Effect on Fly height
23
Effect on Fly height
24
Air bearing/fly model
25
Air bearing/fly model
26
Air bearing/fly model
27
Performance prediction of air bearing
28
Sensitivity analysis
29
Take-off profile
30
Unload Footprints
31
Head-Disk Spacing Budget
32