SiC Thermal Bridge on PCB Substrates for Hotspot Heat Removal

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Solution Overview

Problem

Transistor packages using low thermal conductivity substrates, such as PCBs, face challenges in effectively removing heat generated by components due to limited thermal conductivity, leading to high temperatures that can cause component failure and solder joint failure.

Innovation Solution

Integration of a silicon carbide (SiC) thermal bridge on the substrate board to transfer heat from hotspots to ground connections, utilizing SiC's high thermal conductivity to bridge high thermal gradients with minimal electric performance degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If low thermal conductivity substrates (PCB) are used for transistor packages, then electrical performance is maintained, but heat removal capability deteriorates leading to high temperatures

Engineering Contradiction:

Improveelectrical performanceVSAvoidheat removal capability

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The substrate is segmented into two distinct layers: a low thermal conductivity substrate (PCB) for electrical performance and a high thermal conductivity layer (AlN or diamond) for heat removal. This segmentation allows each layer to perform its specialized function independently, resolving the contradiction between electrical performance and heat removal capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses composite material structure combining PCB substrate with high thermal conductivity materials (AlN or diamond) to create a multi-functional substrate that simultaneously provides electrical performance and superior heat removal capability.

Inventive Principle:

Principle #40Composite materials

2Temperature

If AlN thermal conductor is added to improve heat removal, then thermal conductivity increases, but temperature levels remain substantial due to limited thermal conductivity of AlN

Engineering Contradiction:

Improveheat removal capabilityVSAvoidtemperature levels

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The invention changes the thermal conductivity parameter by replacing AlN with diamond material having superior thermal conductivity (10-20 times higher than AlN), enabling effective heat removal and reducing temperature levels to acceptable ranges.

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

The SiC thermal bridge effectively dissipates heat, reducing temperature rises and preventing component failure, while maintaining electrical integrity by using non-electrically conductive SiC materials.

Implementation Method 1

The thermal bridge is configured to transfer heat from the substrate board including an area adjacent to or on a hotspot of the substrate board to another location on the substrate board

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS12402240B2Silicon carbide thermal bridge integrated on a low thermal conductivity substrate and processes implementing the same

Publication Date: 2025.08.26 WOLFSPEED INC

AI summary

A component includes a substrate board; a thermal bridge structured and arranged on the substrate board, where the thermal bridge is configured to transfer heat from the substrate board including an area adjacent to or on a hotspot of the substrate board; where the thermal bridge is configured to transfer the heat to another location on the substrate board for removal of the heat from the substrate board; and where the thermal bridge may include silicon carbide.