Integrated Side Shield PMR Head for Flux Choking Prevention
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Solution Overview
Problem
Existing perpendicular magnetic recording (PMR) technologies face challenges in achieving self-aligned structures for side and trailing shields, leading to interface flux choking and adjacent track erasure due to the use of separate fabrication processes for these shields.
Innovation Solution
A method is developed to fabricate both side shields and trailing shields in a single process, using a substrate with a magnetic pole and integrated shield structure where the side shields are formed on the substrate and the trailing shield is integral with them, eliminating the interface between the two.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate fabrication processes are used for side shields and trailing shields, then manufacturing flexibility is improved, but interface flux choking occurs leading to adjacent track erasure
Solution Approach 1:
The patent combines the fabrication of side shields and trailing shields into a single integrated structure formed by one continuous electroplating process. The shield structure includes side shields extending from the pole tips and a trailing shield connected to the side shields, forming an integrated magnetic shield that eliminates the interface between separate shields. This merging approach prevents interface flux choking while maintaining manufacturing efficiency through a single process step.
2Reliability
If self-aligned structure is achieved between side shield and trailing shield, then adjacent track erasure is reduced, but fabrication complexity increases due to integrated process requirements
Solution Approach 1:
The patent employs preliminary patterning actions where a photoresist mask is formed with patterns defining both side shield and trailing shield regions before the electroplating process begins. The mask is strategically designed to guide the integrated shield formation, ensuring self-alignment between side and trailing shields during a single electroplating step. This preliminary patterning simplifies the overall process by establishing alignment references in advance.
Solution Approach 2:
The integrated electroplating process serves multiple functions simultaneously: it forms the side shields, forms the trailing shield, and ensures self-alignment between them, all in one operation. The single electroplating step acts as a universal manufacturing method that accomplishes what would otherwise require multiple separate processes, reducing fabrication complexity while achieving self-aligned structures.
3Reliability
If integrated shield structure is formed in one process, then interface flux choking is eliminated, but manufacturing precision requirements increase for single-step formation
Solution Approach 1:
The integrated shield structure is designed to be self-aligning through its geometric configuration. The side shields and trailing shield are formed as a continuous structure where the trailing shield connects to the side shields at defined angles, creating inherent geometric constraints that ensure proper alignment without requiring external alignment mechanisms or multiple positioning steps. The structure serves its own alignment function through its design.
Solution Approach 2:
The patent controls the electroplating process parameters including plating time, current density, and solution composition to achieve uniform shield thickness and proper geometric formation in a single step. By optimizing these parameters, the process achieves the required manufacturing precision for the integrated structure without needing multiple fabrication steps, eliminating interface flux choking while maintaining alignment precision.
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 prevents interface flux choking and reduces adjacent track erasure by ensuring full alignment and integration of the shields, enhancing track density and track profile in PMR heads.
Implementation Method 1
a magnetic pole formed over the substrate, the pole having a pole tip
Implementation Method 2
an integrated shield comprising side shields on the substrate laterally surrounding the pole tip and a trailing shield overlying the pole tip and integral with the side shields
Data Source
AI summary
A PMR head comprises a substrate, a magnetic pole formed over the substrate, the pole having a pole tip having a cross-sectional tapered shape wherein the pole tip is surrounded by a write gap layer, an integrated shield comprising side shields on the substrate laterally surrounding the pole tip and a trailing shield overlying the pole tip and integral with the side shields.