Photonic Comb Structures With Multi-Depth Etching and Clean Trenches
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Solution Overview
Problem
Existing techniques for forming photonic devices with comb-like structures suffer from issues such as undesirable residues, which impact performance due to the use of a single mask layer for etching, leading to incomplete and inefficient fabrication processes.
Innovation Solution
A method involving the formation of dummy tiers and recessed regions across these tiers to etch substrates, creating comb-like structures with varying depths, which are then filled with dielectric material and polished to form effective photonic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single mask layer is used to directly etch the substrate multiple times, then the fabrication process is simplified, but undesirable residues remain in the formed comb-like structures impacting device performance
Solution Approach 1:
The fabrication process is divided into multiple separate etching steps, each with its own dedicated mask layer. The first mask layer forms initial comb-like structures, then a second mask layer forms additional comb-like structures. This segmentation allows each etching step to be independently controlled and cleaned, eliminating residue accumulation while maintaining process simplicity.
Solution Approach 2:
A second mask layer is introduced as an intermediary between the first mask layer and the substrate for the second etching step. This intermediary mask layer protects previously formed structures while enabling precise formation of additional comb-like structures, ensuring clean fabrication without cross-contamination or residue from previous steps.
2Manufacturing precision
If multiple etching steps are performed with separate mask layers, then residue issues are eliminated, but the fabrication process complexity increases
Solution Approach 1:
Multiple comb-like structures with different depths are formed by merging two etching steps that use different mask layers. The first etching step creates comb-like structures extending to a first depth, and the second etching step creates additional comb-like structures extending to a second depth. These structures are merged into a single integrated photonic device, achieving complex functionality through systematic combination of simpler steps.
Solution Approach 2:
The fabrication process transitions from a single-layer mask approach to a multi-layer mask approach, adding a vertical dimension to the masking strategy. The second mask layer is positioned at a different vertical level than the first mask layer, allowing independent control of etching depths for different comb-like structures. This dimensional addition to the masking process enables precise depth control while maintaining overall process manageability.
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 eliminates residue issues and enhances the performance of photonic devices by creating structures with precise depth variations, improving their optical signal processing capabilities.
Implementation Method 1
performing an etching operation to concurrently forming a third plurality of trenches with respective different depths in the substrate through the at least one subgroup of the second plurality of recessed regions
Data Source
AI summary
A method includes: forming a first plurality of tiers that each comprises first and second dummy layers over a substrate, wherein within each tier, the second dummy layer is disposed above the first dummy layer; forming a second plurality of recessed regions in the first plurality of tiers, wherein at least one subgroup of the second plurality of recessed regions extend through respective different numbers of the second dummy layers; and performing an etching operation to concurrently forming a third plurality of trenches with respective different depths in the substrate through the at least one subgroup of the second plurality of recessed regions.