Magnetic Write Pole Fabrication via Vacuum Deposition

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Solution Overview

Problem

Conventional magnetic recording heads face limitations in performance at higher recording densities due to insufficient write field magnitude and magnetic field gradient, particularly in the formation of the main pole.

Innovation Solution

The method involves forming a main pole using a combination of vacuum deposition and electroplating techniques, where vacuum-deposited materials with higher saturation magnetization are used to create a void-free structure, reducing the formation of stripe domains and enhancing the magnetic field gradient.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electroplating is used to form the main pole, then the main pole can be formed with a flat top surface, but the saturation magnetization is insufficient leading to inadequate write field magnitude

Engineering Contradiction:

Improvewrite field magnitudeVSAvoidfabrication process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The main pole formation process is segmented into multiple stages: first vacuum deposition to create a seed layer with high saturation magnetization, then electroplating to build up the main pole structure. This segmentation allows each process to contribute its strengths - vacuum deposition provides high magnetization while electroplating provides structural formation capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses composite material deposition by combining vacuum-deposited magnetic materials (such as CoFeB, CoFe) with electroplated materials. The vacuum-deposited layer serves as both seed layer and magnetic enhancement layer, creating a composite structure that achieves both high saturation magnetization and proper geometric formation.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If conventional electroplating is used, then fabrication is simpler, but the magnetic field gradient is insufficient for higher recording densities

Engineering Contradiction:

Improvemagnetic field gradientVSAvoidfabrication process

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality enhancement by concentrating high saturation magnetization materials specifically at the pole tip region through vacuum deposition. This localized material placement creates enhanced magnetic field gradient where it is most needed for high-density recording, without requiring complex modifications throughout the entire fabrication process.

Inventive Principle:

Principle #3Local quality

3Reliability

If vacuum deposition is used to increase saturation magnetization, then writeability improves, but the fabrication process becomes more complex

Engineering Contradiction:

ImprovewriteabilityVSAvoidfabrication process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges vacuum deposition and electroplating processes into a unified main pole formation sequence. The vacuum-deposited magnetic layer serves dual purposes as both seed layer for electroplating and as the high-magnetization functional layer, eliminating the need for separate layers and simplifying the overall process despite using advanced vacuum deposition technology.

Inventive Principle:

Principle #5Merging (Combining)

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 improves the saturation magnetization of the main pole, leading to increased overwrite gain, writeability, and reliability, while maintaining fabrication efficiency without adverse effects on the magnetic recording head's performance.

Implementation Method 1

A first main pole layer is vacuum deposited, via step 112. A second main pole layer is vacuum deposited, via step 116

Methodology Applied

Scientific EffectVacuum deposition: Physical Vapour Deposition

Implementation Method 2

A portion of the first main pole layer is removed, via step 114. A portion of the second main pole layer is removed, via step 118

Methodology Applied

Scientific EffectIon beam etching: Ion Beam

Data Source

PatentUS9135930B1Method for fabricating a magnetic write pole using vacuum deposition

Publication Date: 2015.09.15 WESTERN DIGITAL TECHNOLOGIES INC

AI summary

A method and system provide a magnetic transducer having an air-bearing surface (ABS) and an intermediate layer. A trench having a shape and location corresponding to a main pole is formed in the intermediate layer. The main pole is provided. At least a portion of the main pole is in the trench. Providing the main pole further includes vacuum depositing a first main pole material layer. The first main pole material layer is thin enough to preclude filling of the trench. The first main pole material layer is then ion beam etched. A second main pole layer is vacuum deposited on the first main pole layer. The second main pole material layer is also thin enough to preclude filling of the trench. An additional main pole layer is also deposited.