Rounded Interlayer Dielectric Edge Coupler for Photonics Micro-Trenching
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Solution Overview
Problem
High-energy reactive ion etching processes used in photonics chip manufacturing often lead to micro-trenching, which damages the waveguide core and is an undesired process artifact, particularly when forming openings for fiber-to-chip couplers.
Innovation Solution
A structure and method involving a dielectric layer with interlayer dielectric layers having rounded regions that overlap with the waveguide core, which reduces micro-trenching by deflecting energetic ions during reactive ion etching, thereby protecting the waveguide core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-energy reactive ion etching is used to form openings through the back-end-of-line stack, then the opening can be completely formed to reveal the waveguide core, but micro-trenching occurs that erodes and damages the waveguide core
Solution Approach 1:
A mandrel structure is formed beforehand at the location where the opening will be etched. This mandrel serves as a protective element during the subsequent high-energy reactive ion etching process, preventing direct damage to the waveguide core while allowing the opening to be formed through the interlayer dielectric stack.
Solution Approach 2:
The mandrel acts as an intermediary protective element between the high-energy ions and the waveguide core. It absorbs or deflects the ion bombardment that would otherwise cause micro-trenching and damage to the waveguide core, while still allowing the etching process to proceed effectively.
2Manufacturing precision
If high-energy reactive ion etching is used to form openings, then the etching process can penetrate through the back-end-of-line stack, but micro-trenching enhances the vertical etch rate causing excessive erosion
Solution Approach 1:
The mandrel structure converts the harmful micro-trenching effect into a beneficial outcome. By positioning the mandrel to overlap with the waveguide core, the controlled micro-trenching that occurs during etching actually helps define the opening boundaries while the mandrel protects the underlying waveguide core from damage.
Solution Approach 2:
The mandrel serves as a mediator that allows the high-energy ion bombardment to proceed (maintaining etching efficiency) while protecting the waveguide core. It absorbs the excess energy that would otherwise cause damaging micro-trenching in the waveguide core region.
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
The rounded regions of the interlayer dielectric layers effectively reduce micro-trenching and damage to the waveguide core, enhancing the reliability and integrity of the edge coupler structure in photonics chips.
Implementation Method 1
The rounded regions of the interlayer dielectric layers effectively reduce micro-trenching and damage to the waveguide core, enhancing the reliability and integrity of the edge coupler structure in photonics chips
Data Source
AI summary
Structures for an edge coupler of a photonics chip and methods of forming an edge coupler for a photonics chip. The structure includes a waveguide core on a dielectric layer, as well as an interconnect structure including a interlayer dielectric layer positioned over the dielectric layer and an opening penetrating through the interlayer dielectric layer to the waveguide core. A region of the interlayer dielectric layer is positioned to overlap with a portion of the waveguide core. The region of the interlayer dielectric layer has a surface that is rounded with a curvature.