Ring Resonator Photonic Package for Variation-Tolerant Coupling

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Solution Overview

Problem

Existing silicon photonics are sensitive to patterning process variations, affecting the coupling efficiency of optical transmission structures due to non-uniform gap spacing between waveguides and resonant structures.

Innovation Solution

The use of racetrack-shaped resonant structures, which are physically separated and partially overlapped, increases the coupling area and gap between waveguides, thereby improving coupling efficiency while minimizing the impact of patterning process variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional silicon photonics structures are used, then manufacturing is simpler, but coupling efficiency is affected by patterning process variations

Engineering Contradiction:

Improvecoupling efficiencyVSAvoidstructure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The resonant structure is divided into multiple discrete elements (e.g., separate rings or segments) rather than a continuous structure. This segmentation allows each element to be positioned independently, reducing sensitivity to patterning variations and improving coupling efficiency through optimized spacing control.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple resonant structures are nested or concentrically arranged around the waveguide, with each nested layer contributing to the overall coupling effect. This nested configuration increases the effective coupling area while maintaining compact footprint and reducing sensitivity to individual patterning variations.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Manufacturing precision

If coupling area between waveguides and resonant structures is increased, then coupling efficiency improves, but device area increases

Engineering Contradiction:

Improvecoupling efficiencyVSAvoidphotonic die area

Core Design Contradiction:

Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The resonant structures are arranged in a three-dimensional configuration around the waveguide, utilizing vertical and radial dimensions rather than only horizontal expansion. This allows increased coupling area through multiple nested layers and optimized spacing, achieving high coupling efficiency within a compact footprint.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Multiple resonant structures are combined in a nested or concentric arrangement, where their coupling effects are additive. This merging of multiple structures achieves the equivalent of a large coupling area while maintaining a compact overall device footprint through efficient spatial utilization.

Inventive Principle:

Principle #5Merging (Combining)

3Manufacturing precision

If gap spacing between waveguides and resonant structures is optimized, then coupling efficiency improves, but sensitivity to patterning variations increases

Engineering Contradiction:

Improvecoupling efficiencyVSAvoidrobustness to patterning variations

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The resonant structure is divided into multiple discrete elements with spacing between them. This segmentation creates multiple coupling interfaces, where the overall coupling efficiency is the sum of individual contributions, reducing sensitivity to variations in any single gap spacing while maintaining optimized average coupling.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The design transitions from optimizing a single critical gap dimension to optimizing a distribution of gap dimensions across multiple segmented elements. This parameter change from single-critical-dimension to multi-parameter optimization reduces sensitivity to patterning variations while maintaining high coupling efficiency through statistical averaging.

Inventive Principle:

Principle #35Parameter changes

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

Enhances coupling efficiency and allows for miniaturization of the photonic die without being affected by patterning process variations, improving the performance and efficiency of optical signal transmission.

Implementation Method 1

at least two racetrack-shaped resonant structures arranged along a second direction different from the first direction and disposed between the first and second waveguides, wherein the at least two racetrack-shaped resonant structures are configured to optically couple the first waveguide to the second waveguide in the second direction

Methodology Applied

Scientific EffectOptical resonance: Resonance

Data Source

PatentUS20250306267A1Package structure having ring resonant structure and method of forming the same

Publication Date: 2025.10.02 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Provided is a package structure including an optical transmission structure and a method of forming the same. The package structure includes: an electronic die; and a photonic die bonding to the electronic die. The photonic die includes: a substrate; an interconnect structure disposed over the substrate; a semiconductor layer disposed between the substrate and the interconnect structure. The semiconductor layer includes: a first waveguide and a second waveguide extending along a first direction; and at least two ring resonant structures arranged along a second direction different from the first direction and disposed between the first and second waveguides. The at least two ring resonant structures are configured to optically couple the first waveguide to the second waveguide in the second direction.