Tapered Waveguide Core for Low-Cost Manufacturing
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Solution Overview
Problem
Current waveguides for thermally-assisted magnetic recording face challenges in achieving high reliability and cost reduction due to the need for high-resolution photolithography, which increases costs and can result in photoresist residue issues during the manufacturing process.
Innovation Solution
A waveguide design featuring a core with a first dielectric material and a cladding of a second dielectric material with a lower refractive index, where the core's front portion tapers with increasing distance from the inlet, allowing for a photoresist mask with a thickness-changing portion that increases in thickness, enabling the formation of a reliable waveguide without the need for high-resolution photolithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-resolution photolithography is used to form a sharp tip portion of the waveguide core, then the manufacturing precision is improved, but the manufacturing cost increases
Solution Approach 1:
The invention changes the geometric parameters of the waveguide core by introducing a tapered structure with gradually varying thickness instead of a sharp tip. This parameter change allows the use of lower-resolution photolithography processes while maintaining adequate light propagation performance, thereby reducing manufacturing costs without completely sacrificing precision requirements
Solution Approach 2:
The invention applies partial action by forming a photoresist mask with varying thickness that exceeds the minimum required coverage at certain regions. This excessive photoresist thickness at the tapered portion compensates for the lower resolution of the photolithography process, allowing standard equipment to achieve the desired structural form without requiring high-resolution tools
2Ease of operation
If ultrasonic waves are used to remove the photoresist mask, then the ease of operation is improved, but the reliability deteriorates due to breaking of the tip portion
Solution Approach 1:
The invention provides beforehand cushioning by designing a tapered waveguide core structure with gradually varying thickness that inherently reduces stress concentration. This structural cushioning protects the tip portion from breaking during photoresist mask removal, even when ultrasonic waves are applied, thereby maintaining reliability while allowing easy operation
Solution Approach 2:
The invention performs preliminary action by carefully controlling the photoresist mask formation process to create a thickness gradient that facilitates gentle removal. The photoresist is designed to be removed more easily from thicker regions first, progressively exposing the tapered core structure without subjecting the tip portion to sudden mechanical stress that would cause breaking
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
The proposed waveguide achieves high reliability and cost reduction by preventing photoresist residue and allowing for lower-cost manufacturing processes while maintaining effective light propagation and near-field light generation for thermally-assisted magnetic recording.
Implementation Method 1
a waveguide including a core 40 allowing light to propagate therethrough and a cladding 20 around the core 40... The core includes a front portion 41A... The thickness of the front portion 41A decreases with increasing distance from the inlet
Implementation Method 2
A known method for generating near-field light is to use a plasmon generator, which is a piece of metal that generates near-field light from plasmons excited by irradiation with laser light
Data Source
AI summary
A waveguide includes a core and a cladding. The core has an inlet on which light is incident. The core includes a front portion and a rear portion located between the front portion and the inlet. The front portion and the rear portion each have a thickness that is a dimension in a first direction and a width that is a dimension in a second direction. The first direction is orthogonal to a propagation direction of the light. The second direction is orthogonal to the propagation direction of the light and the first direction. The thickness of the front portion decreases with increasing distance from the inlet.