Perpendicular Magnetic Write Head Tapered Pole Formation
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Solution Overview
Problem
The formation of a main magnetic-pole layer with a tapered section in perpendicular magnetic recording heads is cumbersome and imprecise due to the need for post-processing operations, which can lead to variations in shape and precision, especially when forming photoresist patterns on underlayers with tapered sections.
Innovation Solution
A method involving the formation of nonmagnetic layers with specific recessed sections, where the additional nonmagnetic layer deposition creates a shallower depth towards the front part, allowing for the precise formation of a tapered main magnetic-pole layer without requiring extensive post-processing, by utilizing the difference in deposition tendencies between these sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If post-processing operations (etching) are performed to form the tapered section of the main magnetic-pole layer, then the tapered shape can be achieved, but the manufacturing complexity increases and precision decreases due to variations in etching amounts
Solution Approach 1:
The patent applies preliminary action by forming the tapered underlayer structure before depositing the magnetic material layer. The underlayer is prepared with a predetermined tapered shape, and then the magnetic layer is deposited conformally on this pre-formed structure. This eliminates the need for subsequent etching operations to create the tapered shape, as the taper is already established in the underlayer. The magnetic layer simply follows the pre-formed tapered geometry, ensuring high precision without post-processing variations.
Solution Approach 2:
The patent inverts the conventional approach by forming the tapered shape in the underlayer rather than in the magnetic-pole layer itself. Instead of depositing a uniform magnetic layer and then etching it to create the taper, the method deposits the magnetic layer on top of a pre-formed tapered underlayer. This inversion transfers the shaping operation to a different layer where it can be more precisely controlled, and the magnetic layer automatically acquires the tapered shape through conformal deposition.
2Ease of manufacture
If photolithography is performed on an underlayer with a tapered section, then the photoresist pattern can be formed, but the exposure region becomes inaccurate due to light reflection from the tapered surface
Solution Approach 1:
The patent applies preliminary action by forming the tapered shape in the underlayer before performing photolithography on the magnetic layer. The photolithography process is then performed on a planar upper surface of the magnetic layer, not on the tapered underlayer surface. This eliminates the light reflection problem that occurs when photolithography is performed directly on tapered surfaces, as the exposure is now done on a flat surface where light incidence is uniform and predictable.
3Shape
If the main magnetic-pole layer is formed in multiple separate processes, then the tapered shape can be achieved, but the manufacturing complexity and time increase
Solution Approach 1:
The patent merges the shaping operation with the underlayer formation process. The tapered structure is created as an integral part of the underlayer fabrication, and the magnetic layer is then deposited in a single conformal deposition step that automatically acquires the tapered shape. This combines what would otherwise be separate shaping and deposition operations into an integrated process, eliminating the need for multiple separate processes to form the tapered magnetic-pole layer.
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 the easy and accurate formation of a main magnetic-pole layer with a tapered section, suitable for concentrating magnetic flux, by determining the shape based on the depth changes in the recessed sections, thus improving the precision and reproducibility of the magnetic flux concentration.
Implementation Method 1
forming an additional nonmagnetic layer on an inner surface of the first and the second recessed sections
Data Source
AI summary
A method of manufacturing a perpendicular magnetic recording head capable of easily and accurately forming a main magnetic-pole layer having a shape suitable for concentrating a magnetic flux is provided. A nonmagnetic layer having a recessed section (a first recessed section and a second recessed section) is formed, and then an additional nonmagnetic layer is formed on an inner surface of the recessed section. Then, a magnetic layer is formed in the recessed section formed with the additional nonmagnetic layer, and then the magnetic layer is cut to form an air bearing surface, so as to form the main magnetic-pole layer.