Heat-Assisted Magnetic Recording Head Internal Mirror Taper-Etching
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Solution Overview
Problem
Heat-assisted magnetic recording heads face challenges in maintaining high light use efficiency due to difficulties in forming precise internal mirrors with large inclined surfaces, leading to reduced laser light reflection and near-field light generation efficiency.
Innovation Solution
The heat-assisted magnetic recording head incorporates an internal mirror with a reflecting film support body featuring multiple inclined surfaces, which are formed through a two-step taper-etching process to enhance precision and prevent deformation, ensuring efficient light reflection and near-field light generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-step taper-etching process is used to form the internal mirror, then the manufacturing process is simpler, but the precision and flatness of the inclined surface deteriorate due to mask deformation
Solution Approach 1:
The patent divides the single-step taper-etching process into two separate steps: a first taper-etching step to form an initial inclined surface, and a second taper-etching step to form the final precise inclined surface. This segmentation allows each step to be optimized independently, with the first step removing bulk material and the second step achieving high precision, thereby resolving the contradiction between manufacturing simplicity and surface precision.
Solution Approach 2:
The first taper-etching step performs a preliminary action by forming an initial inclined surface that serves as a foundation for the second step. This preliminary preparation reduces the etching depth required in the second step, allowing for more precise control and better surface flatness while maintaining overall manufacturing efficiency.
2Strength
If the etching mask is made thicker to prevent deformation during etching, then mask strength increases, but the ability to form precise large-area inclined surfaces deteriorates
Solution Approach 1:
By segmenting the etching process into two steps, the patent reduces the etching depth required in each individual step. This allows the use of thinner masks in each step that can maintain sufficient strength without the deformation issues that would occur with a single thick mask attempting to cover the entire etching depth, thereby resolving the contradiction between mask strength and surface precision.
Solution Approach 2:
The first taper-etching step performs a partial action by removing only a portion of the required etching depth, leaving the remaining depth to be removed in the second step. This partial action in the first step allows the mask to maintain its shape better, while the second step completes the precision work with a freshly applied mask, achieving both adequate mask strength and high surface flatness.
3Productivity
If a large-area inclined surface is formed in a single etching step, then the manufacturing process is faster, but the precision and flatness of the surface deteriorate
Solution Approach 1:
The patent segments the large-area inclined surface formation into two sequential etching steps. The first step covers a larger area with less stringent precision requirements, maintaining high productivity. The second step focuses on the same area with higher precision requirements, achieving the necessary flatness. This segmentation resolves the contradiction by allowing different precision levels in different phases of the same manufacturing process.
Solution Approach 2:
The first taper-etching step performs a preliminary action over the large area, establishing the basic inclined geometry quickly. This preliminary coverage maintains productivity, while the second step refines the surface precision. The preliminary action thus enables both fast initial processing and final high-precision results.
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 allows for higher precision in forming the internal mirror surfaces, preventing light loss and maintaining high use efficiency, thereby improving the generation of near-field light for heat-assisted magnetic recording.
Implementation Method 1
the reflecting film has a first reflecting surface, and a second reflecting surface... the light that comes from above the waveguide is reflected by the internal mirror so that the reflected light travels through the waveguide
Implementation Method 2
a near-field light generating element having a near-field light generating part located in the medium facing surface, a surface plasmon being excited based on the light propagating through the waveguide, the surface plasmon propagating to the near-field light generating part, the near-field light generating part generating near-field light based on the surface plasmon
Implementation Method 3
The step of etching the initial support body includes: a first etching step of taper-etching the initial support body by reactive ion etching using the first etching mask; a second etching step of taper-etching the initial support body by reactive ion etching using the second etching mask
Data Source
AI summary
A manufacturing method for a heat-assisted magnetic recording head includes the step of forming an internal mirror that includes a reflecting film support body and a reflecting film. The reflecting film support body includes first and second inclined surfaces. The reflecting film includes first and second portions that are located on the first and second inclined surfaces, respectively. The step of forming the internal mirror includes the step of forming the reflecting film support body and the step of forming the reflecting film. The step of forming the reflecting film support body forms an initial support body, and performs two taper-etching processes on the initial support body so that the initial support body is provided with the first and second inclined surfaces.