Ion Beam Etching for Waveguide Sidewall Roughness Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing waveguide technologies face challenges in forming angled device structures with reduced sidewall thickness variation, which is crucial for efficient light propagation and overlaying virtual images on ambient environments in augmented, virtual, and mixed reality applications.
Innovation Solution
A method involving the use of ion beam etching with controlled rotation angles to form angled device structures on a substrate, where the substrate is positioned at multiple rotation angles and exposed to an ion beam with specific beam angles to create trenches with minimal sidewall thickness variation, allowing for efficient formation of waveguide structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ion beam etching is used to form angled device structures, then manufacturing precision of sidewall thickness is improved, but device complexity increases due to multiple rotation angles and cycling
Solution Approach 1:
The etching process is divided into multiple cycles, each cycle consisting of positioning at a first rotation angle to etch a portion of the trench, then rotating to a second rotation angle to etch another portion. This segmentation allows precise control of sidewall thickness by treating different trench portions separately through repeated cycling
Solution Approach 2:
The substrate rotation angle is dynamically changed during the etching process between the first rotation angle (for etching) and the second rotation angle (for roughness reduction). This dynamic adjustment enables the ion beam to maintain optimal incidence angles for both precision etching and surface smoothing throughout the manufacturing process
2Manufacturing precision
If multiple rotation angles are used to reduce sidewall thickness variation, then manufacturing precision is improved, but productivity decreases due to repeated positioning and rotation cycles
Solution Approach 1:
The etching process employs periodic cycling between two rotation angles, where the substrate is repeatedly positioned at the first rotation angle for etching and then rotated to the second rotation angle for roughness reduction. This periodic action between contrasting states enables simultaneous achievement of precise trench formation and surface quality improvement
Solution Approach 2:
The ion beam etching process maintains continuous useful action by ensuring that both the first rotation angle positioning and the second rotation angle positioning contribute productively to the final result. Each cycle of positioning and rotation performs dual functions: etching material removal and sidewall roughness reduction, eliminating wasted steps in the manufacturing process
3Manufacturing precision
If ion beam etching with controlled angles is used, then manufacturing precision of angled structures is improved, but use of energy increases due to multiple positioning and etching cycles
Solution Approach 1:
The process utilizes parameter changes by varying the substrate rotation angle between two specific values during the etching cycles. By changing the rotation angle parameter, the ion beam incidence angle relative to the substrate surface is optimized for different process stages: precise etching at the first angle and roughness reduction at the second angle, thereby achieving high precision while managing energy consumption efficiently
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 effectively reduces sidewall thickness variation to less than 20 nm, enhancing the efficiency and performance of waveguide structures by maintaining the desired device angles while increasing throughput through consistent beam angles and reducing the need for reconfiguration.
Implementation Method 1
exposing the substrate to an ion beam, forming first partial trenches defined by adjacent angled device structures
Implementation Method 2
The ion beam is configured to contact the substrate at a beam angle θ relative to a surface normal of the substrate
Data Source
AI summary
Embodiments described herein relate to a method of using an apparatus for forming waveguides. The method includes positioning a substrate at a first rotation angle, exposing the substrate to an ion beam, forming first partial trenches defined by adjacent angled device structures with the first device angle, rotating the substrate to a second rotation angle, exposing the substrate to the ion beam, etching the first partial trenches, and repeating the method from about 1 cycle to about 100 cycles to form a plurality of trenches defined by adjacent angled device structures. The first rotation angle is selected to form one or more angled device structures with a first device angle relative to a vector parallel to the substrate. The ion beam is configured to contact the substrate at a beam angle ϑ relative to a surface normal of the substrate.