Waveguide Combiner Grating Formation with Selective Ion Beam Protection
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Solution Overview
Problem
The existing manufacturing processes for waveguides are time-consuming and costly due to the difficulty in creating gratings with different material properties, orientations, and depth profiles, which limits the capability to form varying grating profiles.
Innovation Solution
A method involving the deposition of a protective material over specific regions of a waveguide combiner substrate, followed by ion beam etching to form gratings with controlled angles and profiles, allowing for the creation of gratings with different depths and orientations, while protecting other regions from etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different mask steps and photolithography methods are used to manufacture gratings with different material properties, orientations, and depths, then grating diversity is achieved, but manufacturing time and cost increase significantly
Solution Approach 1:
The substrate is divided into multiple regions with different grating profiles. Each region is selectively protected or exposed using region-specific protective layers, allowing simultaneous formation of different grating types (e.g., first gratings with 5-45 degree angles, second gratings with 45-85 degree angles) in a single ion beam processing step, eliminating the need for multiple separate photolithography steps
Solution Approach 2:
Protective layers are deposited on specific regions before the ion beam processing step. This preliminary protection allows the ion beam to selectively etch only the desired regions while leaving other regions intact, enabling complex multi-profile grating structures to be formed in one processing cycle rather than requiring sequential mask steps
2Manufacturing precision
If multiple photolithography steps are performed to create varying spacing and depth profiles, then grating precision is improved, but manufacturing complexity increases
Solution Approach 1:
Different regions of the substrate are assigned different protective layer configurations, resulting in locally optimized grating properties. For example, a first region receives a protective layer configuration that produces gratings with 5-45 degree angles, while a second region receives a different configuration for 45-85 degree angles, allowing each region to have precisely tailored grating characteristics without affecting other regions
Solution Approach 2:
The protective layer parameters (thickness, material composition, deposition method) are varied across different regions to control the final grating depth and profile. By changing these parameters locally, the method achieves precise control over grating depth profiles and spacing variations in a single processing step, avoiding the need for multiple photolithography steps
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 enables faster and more cost-effective formation of waveguides with diverse grating profiles, enhancing the efficiency of waveguide manufacturing for augmented reality applications.
Implementation Method 1
directing the ion beam toward the substrate such that at least a portion of the grating material from the one or more first regions of the waveguide combiner is removed
Implementation Method 2
the protective material having a first thickness such that the protective material at least partially inhibits removal of a grating material disposed on the waveguide combiner when an ion beam is directed toward the substrate
Data Source
AI summary
Embodiments of the present application generally relate to methods for forming a plurality of gratings. The methods generally include depositing a material over one or more protected regions of a waveguide combiner disposed on a substrate, the material having a thickness inhibiting removal of a grating material disposed on the waveguide combiner when an ion beam is directed toward the substrate, and directing the ion beam toward the substrate. The methods disclosed herein allow for formation of a plurality of gratings in one or more unprotected regions, while no gratings are formed in the protected regions.