Taper-Etching Dielectric Grooves for Near-Field Light Generation
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Solution Overview
Problem
Conventional taper-etching methods using reactive ion etching struggle to form V-shaped grooves in dielectric materials with constant or almost constant inclination angles, leading to varying angles along the groove, which affects the efficiency of near-field light generation in thermally-assisted magnetic recording heads.
Innovation Solution
A method involving reactive ion etching with a controlled ratio of etching and sidewall protective gas flow rates to maintain a consistent inclination angle, forming a V-shaped groove with predetermined angle intersections, suitable for forming the cladding layer in near-field light generators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional reactive ion etching is used to form V-shaped grooves in dielectric materials, then etching can be performed, but the inclination angles of the groove walls vary along the groove depth, leading to poor manufacturing precision
Solution Approach 1:
The patent applies dynamics by changing the etching gas composition dynamically during the etching process. The gas mixture ratio is adjusted in real-time based on the groove depth, allowing the sidewall protective film deposition rate to be modulated throughout the etching sequence, thereby maintaining constant inclination angles despite varying groove geometry
Solution Approach 2:
The patent implements parameter changes by systematically varying the flow rates of etching gas and sidewall protective gas during different stages of the etching process. This controlled parameter modification ensures that the sidewall protective film forms at the appropriate rate to maintain constant groove wall inclination angles throughout the entire groove depth
2Productivity
If the inclination angle of groove wall faces varies, then etching can be completed faster, but the near-field light generation efficiency decreases due to poor groove geometry
Solution Approach 1:
The patent uses dynamic gas composition adjustment to maintain optimal groove geometry throughout the etching process. By continuously adapting the gas mixture based on groove depth, the method achieves both high etching speed and consistent inclination angles, ensuring efficient near-field light generation without sacrificing productivity
Solution Approach 2:
The patent employs parameter changes in gas flow rates to optimize both etching speed and groove quality. The dynamic adjustment of etching and protective gas parameters enables the process to maintain constant inclination angles while progressing through the dielectric layer at high speed, thereby simultaneously improving productivity and reliability
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 enables the formation of grooves with consistent inclination angles, enhancing the intensity and spot diameter of surface plasmons and near-field light generation, improving the performance of thermally-assisted magnetic recording heads.
Implementation Method 1
taper-etching a portion of the layer to be etched, the portion being exposed from the opening, by reactive ion etching
Implementation Method 2
a second gas contributing to deposition of a sidewall protective film
Implementation Method 3
the light that propagates through the core is totally reflected at the top surface of the core. This causes evanescent light to occur from the top surface of the core
Implementation Method 4
surface plasmons are excited through coupling with the aforementioned evanescent light. The surface plasmons propagate along the edge part to reach the near-field light generating part
Data Source
AI summary
A method of taper-etching a layer to be etched that is made of a dielectric material and has a top surface. The method includes the steps of: forming an etching mask with an opening on the top surface of the layer to be etched; and taper-etching a portion of the layer to be etched, the portion being exposed from the opening, by reactive ion etching so that a groove having two wall faces intersecting at a predetermined angle is formed in the layer to be etched. The step of taper-etching employs an etching gas containing a first gas contributing to the etching of the layer to be etched and a second gas contributing to the deposition of a sidewall protective film, and changes, during the step, the ratio of the flow rate of the second gas to the flow rate of the first gas so that the ratio increases.