Deeper Wrap Around Shield for Magnetic Head ATI Reduction

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Solution Overview

Problem

The miniaturization of components in magnetic disk drives leads to increased adjacent track interference (ATI), which hinders the achievement of higher recording density and storage capacity.

Innovation Solution

The method involves etching an underlayer to reduce its thickness and create an undercut, adding gap material along the sides and in the undercut, and forming a shield along at least a portion of the gap material to minimize ATI.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If component dimensions are reduced to increase recording density, then storage capacity is improved, but adjacent track interference increases

Engineering Contradiction:

Improverecording densityVSAvoidadjacent track interference

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

A nonmagnetic gap material is introduced as an intermediary substance between adjacent magnetic pole structures. This gap material fills the space between poles and prevents magnetic flux from leaking into adjacent tracks, thereby eliminating ATI while preserving the miniaturized structure that enables high recording density.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary anti-action by pre-positioning the nonmagnetic gap material between adjacent pole structures before the magnetic recording process. This preventive measure blocks magnetic flux leakage paths in advance, preventing adjacent track interference before it can occur during writing or reading operations.

Inventive Principle:

Principle #9Preliminary anti-action

2Quantity of substance

If writer dimensions are reduced to achieve higher recording density, then storage capacity is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improverecording densityVSAvoidcomponent fabrication accuracy

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent changes the material parameter of the gap region from magnetic to nonmagnetic material. This parameter change allows for relaxed manufacturing tolerances because the nonmagnetic gap material can be deposited as a conformal layer that automatically maintains proper spacing between poles, reducing the precision requirements for pole positioning and spacing.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If deeper wrap around shield is implemented to minimize ATI, then adjacent track interference is reduced, but device complexity increases

Engineering Contradiction:

Improveadjacent track interferenceVSAvoidmagnetic head structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts the ATI mitigation function from the complex wrap-around shield structure and relocates it to a simpler nonmagnetic gap material layer. By taking out the shielding function and implementing it through material selection rather than complex geometry, the structure is simplified while maintaining ATI protection.

Inventive Principle:

Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach effectively reduces ATI, enabling higher recording density and storage capacity by maintaining the integrity of smaller components and optimizing the magnetic head's design.

Implementation Method 1

etching an underlayer positioned under a main pole for reducing a thickness thereof and creating an undercut under the main pole

Methodology Applied

Scientific EffectEtching:

Implementation Method 2

adding gap material along sides of the main pole and in the undercut

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Data Source

PatentUS8634161B2Systems having writer with deeper wrap around shield and methods for making the same

Publication Date: 2014.01.21 WESTERN DIGITAL TECHNOLOGIES INC

AI summary

A method according to one embodiment includes etching an underlayer positioned under a main pole for reducing a thickness thereof and creating an undercut under the main pole; adding a gap material along sides of the main pole and in the undercut; and forming a shield along at least a portion of the gap material. A magnetic head according to one embodiment includes a main pole; an underlayer positioned under the main pole and spaced therefrom, thereby defining an undercut therebetween; a first layer of gap material extending along sides of the main pole and in the undercut; a second layer of gap material extending continuously along the underlayer under the main pole; and a shield encircling the main pole, wherein the shield extends between the first and second layers of gap material in the undercut. Additional systems and methods are also presented.