Optical Isolation Structure for Silicon Photonic Thermal Management

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Solution Overview

Problem

The integration of thermal interface materials with photonic integrated circuit devices is challenging due to compatibility issues, which lead to significant waveguide insertion loss and potential 'optical blindness' caused by light absorption, scattering, and coupling by thermally conductive fillers.

Innovation Solution

The implementation of an optically compatible thermal interface structure that includes an optical isolation structure, such as a light insulating die attach film, and a thermal interface material, which effectively reduces light coupling effects while facilitating heat conduction from the silicon photonic integrated circuit device to a heat dissipation device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If thermal interface materials with thermally conductive fillers are used to remove heat from photonic integrated circuit devices, then heat dissipation is improved, but light absorption, scattering, and coupling occur causing waveguide insertion loss and optical blindness

Engineering Contradiction:

Improveheat dissipationVSAvoidwaveguide insertion loss

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent introduces an intermediary structure consisting of a light insulating dielectric layer and a light shield layer positioned between the waveguide and thermal interface materials. This intermediary blocks light from interacting with thermally conductive fillers while still allowing heat to be conducted away from the photonic device, thus resolving the contradiction between heat dissipation and optical performance

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The thermal interface path is segmented into multiple functional layers: a light insulating dielectric layer that provides optical isolation, a light shield layer with high optical absorption, and thermal interface materials for heat conduction. This segmentation allows each layer to perform its specific function without interfering with the others, enabling simultaneous heat removal and optical protection

Inventive Principle:

Principle #1Segmentation

2Reliability

If the silicon substrate is thinned to ensure optical beam confinement in waveguides, then optical performance is improved, but thermal interface materials come into close proximity with waveguides increasing light coupling

Engineering Contradiction:

Improveoptical beam confinementVSAvoidlight coupling with thermal interface materials

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A light insulating dielectric layer is introduced as an intermediary between the thinned silicon substrate and thermal interface materials. This layer provides optical isolation preventing light coupling while maintaining thermal conduction path, thus resolving the contradiction between achieving thin substrate for optical confinement and preventing light interaction with thermal materials

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If thermal interface materials are limited in contact area with silicon photonic devices to reduce light coupling, then optical performance is improved, but heat flow path is constrained reducing cooling efficiency

Engineering Contradiction:

Improveoptical performanceVSAvoidcooling efficiency

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent extends the thermal management solution to three dimensions by implementing a layered structure with vertical stacking: optical waveguides in the silicon substrate, light insulating dielectric layer, light shield layer, and thermal interface materials above. This vertical arrangement allows full-area thermal contact for efficient cooling while maintaining optical isolation in the vertical dimension

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 solution enables effective heat management for photonic integrated circuit devices, preventing light coupling issues and ensuring efficient heat dissipation, thereby maintaining optimal operating temperatures and performance.

Implementation Method 1

an optical isolation structure, such as a light insulating die attach film... which reduces light coupling effects

Methodology Applied

Scientific EffectLight isolation: Absorption (EM radiation)

Implementation Method 2

a thermal interface material, which effectively reduces light coupling effects while facilitating heat conduction from the silicon photonic integrated circuit device to a heat dissipation device

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP4099070B1Thermal interface structures for optical communication devices

Publication Date: 2025.06.18 INTEL CORP

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AI summary

The removal of heat from silicon photonic integrated circuit devices is a significant issue in integrated circuit packages. As presented herein, the removal of heat may be facilitated with an optically compatible thermal interface structure (400) on the silicon photonic integrated circuit device (200). These thermal interface structures (400) may include stack-up designs, comprising an optical isolation structure (410) and a thermal interface material (430), which reduces light coupling effects, while effectively conducting heat from the silicon photonic integrated circuit device (200) to a heat dissipation device (300), thereby allowing effective management of the temperature of the silicon photonic integrated circuit device (200).