Magnetic Write Head With Beveled Trailing Edge

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Solution Overview

Problem

Conventional magnetic recording heads with front shield gaps (FSG) suffer from side track erasure (STE) and adjacent track interference (ATI), which degrade their reliability, especially at high data-writing rates, due to the overhangs that separate the front shield from the side shields.

Innovation Solution

A method for forming a write head without front shield gap overhangs, where a layer of pole material is deposited on a substrate, and a masking material is used to create a write pole with beveled side walls and a sacrificial material is filled in trenches, allowing for the deposition of a front shield gap without overhangs, thereby eliminating STE and ATI.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If front shield gap overhangs are used to separate front shield from side shields, then on-track performance is improved, but side track erasure and adjacent track interference occur which degrade reliability

Engineering Contradiction:

Improveon-track performanceVSAvoidrecording head reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent removes the front shield gap overhangs that were previously used to separate the front shield from side shields. By extracting this problematic structural element, the invention eliminates the source of side track erasure and adjacent track interference, thereby resolving the reliability issue while maintaining acceptable on-track performance through alternative shielding configurations

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the front shield and side shields by eliminating the separating overhangs, creating a continuous shielding structure. This integration removes the harmful electromagnetic field leakage that occurred at the gap interface, simultaneously improving reliability while the merged structure maintains the necessary field confinement for on-track performance

Inventive Principle:

Principle #5Merging (Combining)

2Productivity

If write field gradient is increased by providing magnetic shielding, then more data can be recorded in smaller spaces, but side track erasure and adjacent track interference are generated

Engineering Contradiction:

Improvedata recording capacityVSAvoidside track erasure and adjacent track interference

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies magnetic shielding selectively in specific locations to maximize write field gradient where needed for high-density recording, while avoiding shielding configurations that would generate side track erasure and adjacent track interference. The shielding is optimized to provide local field enhancement without creating harmful electromagnetic effects in adjacent tracks

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent converts the potential harmful effect of strong magnetic fields into a beneficial outcome by carefully designing the shielding configuration to confine the write field gradient to the intended track area. The magnetic shielding that could potentially cause interference is instead configured to direct and contain the magnetic flux, transforming what could be harmful into a force that enables higher data density without side effects

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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

The solution effectively reduces STE and ATI, enhancing the reliability of the recording head by maintaining the write field gradient while avoiding detrimental interferences, thus improving on-track performance.

Implementation Method 1

A layer of pole material is deposited on a substrate

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Implementation Method 2

A masking material is deposited over a portion of the top surface

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Implementation Method 3

At least a portion of at least one trench formed by removal of the material from the layer of pole material is filled with a sacrificial material

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Implementation Method 4

Front shield gap material is deposited over the beveled trailing edge surface and over portions of the side walls

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Data Source

PatentUS9972345B1Method for making a write head for magnetic recording

Publication Date: 2018.05.15 SEAGATE TECH LLC

AI summary

A method includes depositing a layer of pole material on a substrate. The layer of pole material has a bottom surface that is adjacent to the substrate and a top surface that is opposite the bottom surface. A masking material is deposited over a portion of the top surface. Material from the pole material unprotected by the masking material is removed to form a write pole having first and second side walls. At least a portion of a trench formed by removal of the material from the layer of pole material is filled with a sacrificial material. The mask and a portion of the write pole at the top surface are removed to form a beveled trailing edge surface. The sacrificial material is then removed. Front shield gap material is deposited over the beveled trailing edge surface and over portions of the side walls.