Variable Depth Grating Etching via Mask Thickness Control
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Solution Overview
Problem
The existing methods for forming optical devices with different structures and slant angles or depths across a single substrate are time-consuming and costly, requiring substantial hardware reconfiguration and complex processes like gray-tone lithography.
Innovation Solution
A method involving a mask layer with specific openings on a substrate, followed by etching to recess the areas, forming a grating material, and then etching trenches at non-zero angles to create structures with varying depths and orientations, using an ion beam source within a chamber to control the etching process without reconfiguring the hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gray-tone lithography is used to form structures with different depths, then variable-depth optical devices can be produced, but the process becomes time-consuming and costly
Solution Approach 1:
The substrate surface is divided into multiple processing areas with different mask layer thicknesses. Each area is selectively etched to a different depth by controlling the ion beam exposure time and mask thickness, enabling parallel production of structures with varying depths without requiring sequential gray-tone lithography steps.
Solution Approach 2:
The mask layer is pre-formed with varying thicknesses across different processing areas before the etching process. This preliminary structuring of the mask layer allows the etching process to automatically produce different depths in different areas through selective exposure, eliminating the need for complex real-time depth control during lithography.
2Manufacturing precision
If ion beam chamber hardware is reconfigured to change slant angle, then structures with different slant angles can be formed, but the process becomes time-consuming and complex
Solution Approach 1:
Different regions of the substrate are assigned different mask layer thicknesses corresponding to different desired slant angles. The ion beam etches each region to a depth determined by its local mask thickness, automatically producing structures with different slant angles in different areas without requiring hardware reconfiguration between regions.
Solution Approach 2:
The mask layer thickness parameter is varied across different processing areas to control the etch depth and resulting slant angle. By changing this geometric parameter of the mask layer rather than the hardware configuration, the system achieves slant angle variation through a simple, fixed ion beam chamber setup.
3Manufacturing precision
If multiple processing steps are used to form variable-depth structures, then precise depth control is achieved, but manufacturing time increases
Solution Approach 1:
The mask formation and depth specification functions are merged into a single step by directly forming the mask layer with the desired thickness profile that corresponds to the final structure depths. This eliminates separate lithography and etch depth control steps, achieving precise variable depth control in one integrated process.
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 simplifies the manufacturing process, reducing time and costs by allowing for the formation of optical devices with variable structures and depths without the need for hardware reconfiguration, enhancing manufacturing efficiency and expanding application ranges.
Implementation Method 1
The ion beam source is configured to generate an ion beam... etching the substrate to recess the first and second processing areas... etching the grating material in the first and second processing areas
Data Source
AI summary
Methods of producing grating materials with variable height fins are provided. In one example, a method may include providing a mask layer atop a substrate, the mask layer including a first opening over a first processing area and a second opening over a second processing area. The method may further include etching the substrate to recess the first and second processing areas, forming a grating material over the substrate, and etching the grating material in the first and second processing areas to form a plurality of structures oriented at a non-zero angle with respect to a vertical extending from a top surface of the substrate.