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ENE692

LECTURE 4_2HGA Technology

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Basic HGA Technology • HGA assembly process

• HGA process control

• Suspension design and function

• Slider design and function

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HGA Assembly process

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Typical HGA process flow

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HGA mechanical controls

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HGA alignment

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HGA pre-load

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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 A ssembly) processes can produce significant shift of th

e mean and sigma of gram load and flying height.

• Gram load adjust can be used to compensate for the d eviations caused by crown, camber, etch depths, PSA,

stacking tolerances etc. on the flying heights.

Motivations from Gram load adjustment

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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 directionbetween the two sides of the slider.

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How does the gram load adjustment work?

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HGA PSA/RSA

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Gimbal bond strength

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Fly Height

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Fly Height

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Impact of contamination

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Suspension design and function

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Gimbal strength testing

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Stress due to buckling and pitch

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Slider components

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Slider components

• Air bearing

• Read/Write circuit

• Trailing edge

• Leading edge

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Air bearing/fly model

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Fly height history

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Effect on Fly height

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Effect on Fly height

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Air bearing/fly model

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Air bearing/fly model

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Air bearing/fly model

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Performance prediction of air bearing

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Sensitivity analysis

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Take-off profile

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Unload Footprints

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Head-Disk Spacing Budget