Magnetic Transducer Pole Bevel via Stop Layer Depression
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Solution Overview
Problem
Conventional perpendicular magnetic recording (PMR) transducer fabrication methods fail to achieve improved writability and signal-to-noise ratio, as they result in a pole shape and magnetic flux distribution that do not adequately support enhanced reverse overwrite performance.
Innovation Solution
A method involving a nonmagnetic stop layer with a controlled bevel is used, where a depression is formed in the stop layer to create a leading edge bevel, and an intermediate layer is deposited with a flat top surface, allowing for the formation of a trench with a profile corresponding to the pole, which includes a leading edge bevel matching the stop layer's bevel, thereby improving the pole's shape and magnetic flux distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional trench formation method is used in aluminum oxide layer, then the pole can be formed with reverse angle sidewalls, but the writability and signal-to-noise ratio are insufficient
Solution Approach 1:
A bevel is pre-formed in the stop layer before the intermediate layer is deposited and the trench is etched. This preliminary bevel structure is then replicated in the final pole, achieving the desired shape without requiring complex trench formation processes. The bevel is created by depositing material at an angle or by mechanical means before subsequent processing steps.
Solution Approach 2:
A stop layer is introduced as an intermediary layer between the underlayer and the intermediate layer. This stop layer serves multiple functions: it acts as an etch stop during trench formation, provides a surface for preliminary bevel formation, and enables precise control of the pole shape. The stop layer is removed after serving its purpose, leaving the desired pole structure.
2Shape
If a trailing edge bevel is formed by removing pole materials, then the pole shape is modified, but the leading edge shape control is insufficient
Solution Approach 1:
The bevel is formed in the stop layer before the intermediate layer and pole materials are deposited. This preliminary formation of the bevel geometry allows the final pole to inherit the desired shape characteristics without requiring post-deposition modification. The process is simplified because the bevel is built-in rather than carved out later.
Solution Approach 2:
Instead of forming the bevel by removing material from the pole (as in conventional trailing edge bevel formation), the bevel is formed by depositing or preparing the stop layer in a beveled configuration before the pole materials are added. This inverted approach builds the shape rather than subtracting it, improving leading edge control.
3Ease of manufacture
If the intermediate layer has a non-flat top surface, then the trench formation may be simplified, but photolithography precision is degraded
Solution Approach 1:
The structure is segmented into distinct functional layers: the stop layer with the bevel, the intermediate layer with flat top surface for photolithography, and the pole structure. This segmentation allows each layer to optimize its function - the stop layer provides shape definition while the intermediate layer provides a flat surface for precise patterning.
Solution Approach 2:
The intermediate layer acts as an intermediary between the beveled stop layer and the pole formation process. Its flat top surface provides a stable platform for photolithography and trench patterning, while its bottom surface conforms to the beveled stop layer geometry. This intermediary layer decouples the shape definition function from the patterning function.
Data Source
AI summary
A method provides a pole of magnetic recording transducer. A nonmagnetic stop layer having a thickness and a top surface is provided. A depression that forms a bevel is provided in the stop layer. The bevel has a depth less than the thickness and a bevel angle with respect to a remaining portion of the top surface. The bevel angle is greater than zero and less than ninety degrees. An intermediate layer having a substantially flat top surface is provided over the stop layer. A trench is formed in the intermediate layer via a removal process. The trench has a profile corresponding to the pole. The stop layer is a stop for the removal process. The method also includes providing the pole in the trench. The pole has a leading edge bevel corresponding to the bevel in the stop layer.