Magnetic Head Writer With Embedded Write Gap Between Wear-Resistant Pole Tips
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Solution Overview
Problem
The challenge lies in defining narrow pole tips and incorporating wear-resistant materials at the media bearing surface of magnetic heads, particularly as track widths narrow, making the pole tip definition process more difficult and costly, and affecting the control of pole tip width and wear resistance.
Innovation Solution
A magnetic head fabrication method involving a serial sequence of wear-resistant bottom pole tip deposition, write gap deposition, and wear-resistant top pole tip deposition, followed by a two-stage ion mill process to define the zero throat location and dimensions of the pole tips and track width, utilizing materials like CZT, nitride wear-resistant layers, and alumina for the write gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pole tip definition process is performed at the top pole level near the end of fabrication, then pole tip width control is achieved, but manufacturing cost increases and processing errors become more costly
Solution Approach 1:
The patent performs pole tip definition at the bottom pole level before completing the full writer fabrication sequence. By defining the pole tip width early in the process using the bottom pole as a template, the invention avoids costly rework at later stages while maintaining precise dimensional control. The bottom pole tip definition serves as a preliminary action that guides subsequent top pole fabrication.
Solution Approach 2:
The fabrication process is divided into distinct stages: bottom pole formation with embedded write gap, followed by top pole formation. The pole tip definition is segmented into bottom pole tip definition (performed early) and top pole tip formation (performed later using the bottom pole tip as a reference). This segmentation allows precise control to be achieved at the optimal point in the process sequence.
2Quantity of substance
If track width is reduced to increase data capacity, then storage density improves, but pole tip definition difficulty increases
Solution Approach 1:
The bottom pole tip structure serves as a self-generated template for defining the top pole tip dimensions. By using the already-formed bottom pole tip (with its precisely controlled narrow width) as a reference during top pole formation, the process automatically ensures matching dimensions without requiring separate measurement and adjustment steps. This self-service approach simplifies narrow track width fabrication.
Solution Approach 2:
The invention replaces complex mechanical measurement and adjustment systems with a field-based approach. During top pole formation, the bottom pole tip's magnetic field or physical presence serves as a guide for depositing or forming the top pole material to the correct dimensions. This substitution of mechanical measurement with field-based guidance reduces definition difficulty for narrow tracks.
3Reliability
If wear-resistant materials are incorporated at the media bearing surface, then head durability improves, but pole tip width control becomes more difficult
Solution Approach 1:
The patent applies different material properties to different locations: the bottom pole body uses standard magnetic material, while only the bottom pole tip region receives wear-resistant coating. Similarly, the top pole tip receives wear-resistant material. This localized application of wear resistance preserves the precision of pole tip dimensions while providing durability only where contact with media occurs.
Solution Approach 2:
Wear-resistant materials are deposited on the bottom pole tip before the top pole is formed. This preliminary coating establishes a durable foundation that maintains its dimensional integrity during subsequent processing steps. The pre-applied wear layer on the bottom pole tip serves as a stable reference surface for defining the top pole tip dimensions.
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 method enables precise control of pole tip dimensions and wear resistance, ensuring accurate track width definition and reducing the risk of processing errors, thereby improving the reliability and efficiency of magnetic head fabrication.
Implementation Method 1
wear-resistant bottom pole tip deposition, write gap deposition, and wear-resistant top pole tip deposition
Implementation Method 2
two-stage ion mill process which defines the zero throat location and the dimensions of the pole tips and the bottom pole body
Data Source
AI summary
A method of fabricating a magnetic writer includes depositing a wear-resistant bottom pole tip layer on a bottom pole; depositing a write gap layer on the bottom pole tip layer; and depositing a wear-resistant top pole tip layer on the write gap layer. The layers are patterned such that the write gap layer and the top pole tip layer each have a track width facing a media surface and the write gap layer and the top pole tip layer each have the same length equal to a throat height between the media surface and a zero throat location. The bottom pole tip layer and the bottom pole are patterned such that the bottom pole tip layer has the track width facing the media surface and the bottom pole has a bottom pole tip at the media surface with the bottom pole tip having the track width facing the media surface.