Slanted Nanostructure Lithography on Glass With Precise Angle Control
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Solution Overview
Problem
The existing methods for forming nanostructures on waveguides are challenging due to difficulty in accurately controlling the size and alignment of slanted nanostructures, often requiring over-etching which can damage the substrate.
Innovation Solution
A method involving multiple alternating layers of different materials is used, where each layer is deposited and etched to form slanted nanostructures with precise control over their angle and alignment, utilizing lithography tools to ensure accurate formation and minimize substrate damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ion beams are used to etch nanostructures, then the slanted profile can be controlled, but the angle control is difficult and over-etching occurs removing substrate portions
Solution Approach 1:
The patent segments the nanostructure formation into multiple distinct steps: first forming the nanostructures with a lithography tool, then separately etching the sidewalls to create the slanted profile. This segmentation allows precise control of each step independently, preventing over-etching while achieving the desired slanted angle.
Solution Approach 2:
The patent performs preliminary action by first forming the nanostructures with vertical sidewalls using a lithography tool before performing the sidewall etching step. This preliminary formation establishes a controlled foundation that prevents substrate removal during the subsequent slanted profile creation.
2Manufacturing precision
If conventional ion beam etching is used, then nanostructures can be formed, but the thickness and width are inconsistent
Solution Approach 1:
The patent divides the manufacturing process into two independent stages: first forming the nanostructure body with consistent dimensions using lithography, then separately creating the slanted sidewalls through controlled etching. This segmentation ensures dimensional consistency while simplifying process control.
Solution Approach 2:
The patent replaces the mechanical ion beam etching system with a lithography tool for the primary nanostructure formation, providing superior dimensional control. The subsequent sidewall etching uses a separate, more controllable process to achieve the slanted profile without compromising the original dimensions.
3Manufacturing precision
If over-etching is performed to ensure consistent nanostructure dimensions, then dimension consistency is achieved, but substrate portions are inadvertently removed
Solution Approach 1:
The patent segments the etching process into two distinct phases: first forming the nanostructure with precise dimensions, then separately etching only the sidewalls to create the slanted profile. This segmentation eliminates the need for over-etching and prevents substrate material loss.
Solution Approach 2:
The patent introduces an intermediary step of forming vertical sidewalls first, which acts as a protective intermediary during the subsequent slanted profile etching. This intermediary structure prevents direct etching of the substrate while still achieving the desired slanted nanostructure profile.
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 the accurate and controlled formation of slanted nanostructures on transparent substrates, improving the precision and reducing substrate damage, enabling better overlay of virtual images in augmented reality applications.
Implementation Method 1
performing a first process with a lithography tool comprising: depositing a first layer of a first material on a first surface of a transparent substrate
Implementation Method 2
removing one or more first portions of the first layer of the first material to form one or more trenches
Data Source
AI summary
The present disclosure generally relates to methods of forming optical devices comprising nanostructures disposed on transparent substrates. A first process of forming the nanostructures comprises depositing a first layer of a first material on a glass substrate, forming one or more trenches in the first layer, and depositing a second layer of a second material in the one or more holes to trenches a first alternating layer of alternating first portions of the first material and second portions of the second material. The first process is repeated one or more times to form additional alternating layers over the first alternating layer. Each first portion of each alternating layer is disposed in contact with and offset a distance from an adjacent first portion in adjacent alternating layers. A second process comprises removing either the first or the second portions from each alternating layer to form the plurality of nanostructures.