Optical Ring Waveguide Vertical Coupling for Stable Gap Control

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Solution Overview

Problem

Existing silicon photonics devices face challenges in coupling efficiency due to variations in gap spacing between ring waveguides and input/output waveguides caused by patterning processes, leading to suboptimal performance in silicon-on-insulator photonic devices.

Innovation Solution

Implementing a vertical coupling mechanism where the ring waveguide and input/output waveguides are made of different materials and located in different layers, allowing for precise control of the gap distance through the thickness of the interposed dielectric material, enhancing coupling efficiency and loss characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If horizontal coupling between ring waveguide and I/O waveguides is used in the same layer, then device integration is achieved, but coupling efficiency deteriorates due to variations in gap spacing caused by patterning processes

Engineering Contradiction:

Improvedevice integrationVSAvoidcoupling efficiency

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent transitions from horizontal coupling in the same layer to vertical coupling across different layers. The ring waveguide is positioned in a first horizontal plane while I/O waveguides are positioned in a second horizontal plane at a different elevation, with dielectric layers separating them. This vertical arrangement eliminates sensitivity to in-plane patterning variations while maintaining integration, directly resolving the contradiction between ease of manufacture and coupling efficiency.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Dielectric layers are introduced as intermediary elements between the ring waveguide and I/O waveguides. These dielectric layers provide precise vertical spacing control through their thickness, acting as mediators that enable consistent coupling gaps independent of lateral patterning processes. The intermediary dielectric structure resolves the contradiction by decoupling the spacing control from the problematic lateral patterning step.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If vertical coupling with different layers is implemented, then coupling efficiency is improved through precise gap control, but device complexity increases due to multiple layers and materials

Engineering Contradiction:

Improvecoupling efficiencyVSAvoidlayer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The dielectric layers serve multiple functions simultaneously: they provide vertical spacing control for coupling efficiency, act as structural support between layers, and enable planar integration compatible with standard semiconductor fabrication. This multi-functionality reduces the need for additional specialized components, thereby mitigating the complexity increase while achieving improved coupling efficiency.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the spatial parameter from lateral positioning in the same plane to vertical positioning across different planes. By controlling the vertical distance through dielectric layer thickness rather than lateral gap through patterning, the system achieves precise gap control with standard thin-film deposition processes, reducing the complexity burden compared to achieving similar precision through lateral lithography.

Inventive Principle:

Principle #35Parameter changes

3Loss of energy

If ring waveguide and I/O waveguides are made of different materials in different layers, then loss characteristics are improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improveoptical lossVSAvoidlayer alignment

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical lateral alignment requirements with vertical stacking based on dielectric layer thickness. Instead of relying on precise lateral positioning through complex lithography and alignment processes, the coupling gap is determined by the vertically stacked dielectric layer thickness, which can be controlled with standard thin-film deposition precision. This substitution reduces manufacturing precision requirements while enabling different materials for optimized optical loss characteristics.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 vertical coupling scheme improves the coupling efficiency and loss characteristics of optical devices, providing better performance and flexibility in design for optical communication systems.

Implementation Method 1

an I/O waveguide embedded in the dielectric layer and optically coupled to the ring waveguide in a vertical manner

Methodology Applied

Scientific EffectOptical coupling: Waveguide (optics)

Data Source

PatentUS12572050B2Semiconductor device including optical ring waveguide

Publication Date: 2026.03.10 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A semiconductor device and a manufacturing method thereof are provided. The device includes a dielectric layer, a ring waveguide embedded in the dielectric layer, and an input/output (I/O) waveguide embedded in the dielectric layer and optically coupled to the ring waveguide in a vertical manner. Materials of the dielectric layer, the ring waveguide, and the I/O waveguide are different.