Magnetic Main Pole Side Shield Formation
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Solution Overview
Problem
Conventional methods for forming the main pole of a magnetic head face challenges such as bending of the pole and difficulty in maintaining pole shape integrity for narrow widths, as well as issues with forming a wrap-around shield.
Innovation Solution
A method involving the formation of a side shield layer of ferromagnetic material on a substrate, with regions covered and uncovered by the shield, followed by masking, trench formation, and deposition of a pole layer with a nonmagnetic material, allowing for a thicker pole layer where the substrate is not covered by the side shield, which enhances pole shape integrity and facilitates wrap-around shield formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ion milling process is used to form main pole from full film layer, then wrap around shield can be formed, but pole shape integrity cannot be maintained for narrow pole widths
Solution Approach 1:
The invention divides the pole formation process into separate stages: first forming the side shield layer, then creating the pole trench, and finally depositing the pole material. This segmentation allows the side shield to be formed independently before the pole, enabling narrow pole widths while maintaining shape integrity through the structured sequential process.
Solution Approach 2:
The side shield layer is formed in advance before the pole trench is created. This preliminary action establishes the side shield structure first, which then serves as a template and constraint for subsequent pole formation, ensuring that the pole maintains its shape integrity during the narrowing process.
2Manufacturing precision
If trench method is used to form main pole, then pole shape integrity is maintained, but wrap around shield cannot be formed easily
Solution Approach 1:
The invention segments the structure formation by first creating the side shield layer as a separate entity, then forming the pole trench within or adjacent to it. This segmentation enables both the pole shape integrity (through controlled trench formation) and wrap around shield creation (through the side shield layer that wraps around the pole structure).
Solution Approach 2:
The pole structure is nested within the side shield layer configuration. The side shield layer is formed first, then the pole trench is created within this established structure, and the pole material is deposited into the trench. This nesting approach allows the wrap around shield to encompass the pole while maintaining precise pole shape control.
3Ease of manufacture
If pole layer is made uniformly thick, then manufacturing is simpler, but pole shape integrity deteriorates for narrow widths
Solution Approach 1:
The pole layer is designed with non-uniform thickness, being thicker in regions where the side shield provides support and narrower where precision is critical. This local variation in thickness is achieved through controlled deposition processes that account for the underlying side shield topography, maintaining pole shape integrity while accommodating manufacturing constraints.
Data Source
AI summary
A method according to another embodiment includes forming a side shield layer of ferromagnetic material above a substrate; masking the side shield layer; milling an unmasked region of the side shield layer for forming a pole trench therein; and forming a pole layer in the pole trench. A structure according to one embodiment includes a substrate; a side shield layer of ferromagnetic material on the substrate, wherein the substrate has a region covered by the side shield layer and a region not covered by the side shield layer; a pole trench in the side shield layer and the region of the substrate not covered by the side shield layer; a layer of nonmagnetic material in the pole trench; and a pole layer in the pole trench, wherein the pole layer has a greater thickness above the region of the substrate not covered by the side shield layer than above the region of the substrate covered by the side shield layer.