Thermally-Assisted Magnetic Recording Head Main Pole Formation
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Solution Overview
Problem
The challenge in forming a main pole for a thermally-assisted magnetic recording head with a specific configuration, where the core is located farther from the substrate than the plasmon generator, and the main pole is interposed between the core's end face and the medium facing surface, is that it requires a complex shape with a rear end face perpendicular to the substrate and a front end face with varying width, which is difficult to manufacture effectively.
Innovation Solution
A method involving multiple etching steps with masks to form an accommodation layer and main pole, where the etching masks define the shape of the accommodation layer's wall faces, allowing the main pole to be formed with a rear end face perpendicular to the substrate and a front end face with a smaller width closer to the substrate, facilitating efficient transformation of light into near-field light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main pole is configured with a complex shape (rear end face perpendicular to substrate, front end face with varying width), then the write magnetic field generation and light transformation efficiency are improved, but the manufacturing difficulty increases
Solution Approach 1:
The patent applies segmentation by dividing the main pole formation process into multiple etching steps with different masks. The first etching step forms the accommodation layer with a specific shape, and the second etching step forms the main pole with the desired complex geometry. This segmentation allows the complex shape to be achieved through controlled, sequential manufacturing steps rather than a single difficult step.
Solution Approach 2:
The patent employs preliminary action by first forming the accommodation layer with a predetermined shape before forming the main pole. The accommodation layer serves as a pre-prepared structure that guides and constrains the subsequent main pole formation, ensuring the final complex geometry is achieved accurately. This preliminary structuring simplifies the overall manufacturing process.
2Reliability
If the core is located farther from the substrate than the plasmon generator, then the light propagation and near-field light generation are improved, but the spatial arrangement complexity increases
Solution Approach 1:
The patent resolves the spatial arrangement complexity by utilizing vertical dimensionality. The core is positioned at a higher elevation than the plasmon generator, creating a layered vertical structure. This dimensional arrangement allows light to propagate efficiently from the core to the plasmon generator while maintaining clear spatial separation, avoiding the need for complex lateral arrangements.
3Reliability
If the front end face of the main pole has a smaller width closer to the substrate, then the light transformation to near-field light is enhanced, but the etching precision requirements increase
Solution Approach 1:
The patent applies local quality by creating a non-uniform width profile in the main pole's front end face. The width varies along the vertical axis, being smaller near the substrate and larger toward the top. This localized geometric variation is achieved through controlled etching processes that selectively remove material at different rates or depths, optimizing the light transformation efficiency at specific locations without requiring uniform precision throughout the entire structure.
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 allows for the easy formation of a main pole with the desired shape, enhancing the generation of a large write magnetic field and efficient light transformation into near-field light, improving the thermally-assisted magnetic recording process.
Implementation Method 1
A method involving multiple etching steps with masks to form an accommodation layer and main pole
Implementation Method 2
a plasmon generator... configured so that a plasmon is excited based on the light propagating through the core, and the near-field light generating part generates near-field light based on the plasmon
Implementation Method 3
a main pole that produces a write magnetic field for writing data on the recording medium
Implementation Method 4
When writing data, a write magnetic field and heat are simultaneously applied to the area of the recording medium where to write data, so that the area rises in temperature and drops in coercivity
Data Source
AI summary
In a method of forming a main pole, an initial accommodation layer is etched by RIE using a first etching mask having a first opening, whereby a groove is formed in the initial accommodation layer. Next, a part of the initial accommodation layer including the groove is etched by RIE using a second etching mask having a second opening, so that the groove becomes an accommodation part. The main pole is then formed in the accommodation part. The first etching mask has first and second sidewalls that face the first opening and are opposed to each other at a first distance in a track width direction. The second etching mask has third and fourth sidewalls that face the second opening and are opposed to each other at a second distance greater than the first distance.