Power Module Heat Dissipation via Segmented Ceramic Coating

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Solution Overview

Problem

Existing power modules face challenges in maximizing heat dissipation performance due to limitations in the thickness of the metal layer and the occurrence of internal residual stress and ceramic fracture, particularly in direct bonded copper (DBC) substrates, which restrict the use of thick metal layers and thin ceramic substrates.

Innovation Solution

A power module design incorporating a thick metal lead frame and a ceramic coating layer on both sides of the semiconductor device, with a metal spacer for heat and electrical transmission, and a ceramic coating layer that is thin enough to prevent ceramic fracture and enhance heat dissipation efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the thickness of the metal layer is increased to increase heat dissipation area, then heat dissipation performance is improved, but internal residual stress accumulates and interfacial delamination occurs

Engineering Contradiction:

Improveheat dissipation performanceVSAvoidinterfacial delamination

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The invention divides the ceramic layer into two separate layers: a first ceramic layer bonded to the metal layer and a second ceramic layer bonded to the semiconductor device. This segmentation reduces the thickness of each individual ceramic layer, thereby reducing internal residual stress and preventing interfacial delamination while maintaining adequate heat dissipation performance through the combined thickness of both ceramic layers.

Inventive Principle:

Principle #1Segmentation

2Loss of energy

If the thickness of the metal layer is increased to improve heat dissipation, then cooling efficiency is improved, but manufacturing difficulty increases

Engineering Contradiction:

Improvecooling efficiencyVSAvoidmanufacturing difficulty

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

By segmenting the ceramic layer into two thinner layers, the invention enables the use of a thicker metal layer for improved heat dissipation while making the overall structure manufacturable. The thinner ceramic layers are easier to bond and less prone to defects, resolving the manufacturing difficulty associated with thick metal layer configurations.

Inventive Principle:

Principle #1Segmentation

3Reliability

If a heat transfer material is interposed between ceramic substrate and copper layer, then electrical insulation is achieved, but heat dissipation performance is limited

Engineering Contradiction:

Improveelectrical insulationVSAvoidheat dissipation performance

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The invention removes the heat transfer material from between the ceramic layer and the copper layer. Instead, the copper layer is directly bonded to the first ceramic layer, eliminating the thermal resistance introduced by the heat transfer material while maintaining electrical insulation through the ceramic layer itself.

Inventive Principle:

Principle #2Taking out (Extraction)

4Loss of energy

If the thickness of the ceramic substrate is reduced to improve heat dissipation, then heat dissipation performance is improved, but ceramic fracture occurs

Engineering Contradiction:

Improveheat dissipation performanceVSAvoidceramic fracture

Core Design Contradiction:

Loss of energyVSStrength

Solution Approach 1:

The invention segments the thin ceramic substrate into two separate ceramic layers, each with adequate thickness to prevent fracture. The first ceramic layer is bonded to the metal layer and the second ceramic layer is bonded to the semiconductor device, allowing each layer to have sufficient thickness for mechanical strength while the combined structure achieves the desired heat dissipation performance.

Inventive Principle:

Principle #1Segmentation

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 design effectively maximizes heat dissipation performance, minimizes internal stress, and improves high-temperature reliability by allowing for a thicker metal layer without ceramic fracture, while also simplifying the coating process and eliminating the need for additional EMC processing.

Implementation Method 1

a coating layer bonded to each of an upper surface of the upper substrate and a lower surface of the lower substrate

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a metal spacer for heat and electrical transmission

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

ceramic and metal are bonded together through a eutectic reaction at a temperature of equal to or greater than 1065° C.

Methodology Applied

Scientific EffectEutectic reaction: Melting

Data Source

PatentUS11373924B2Power module having heat dissipation structure

Publication Date: 2022.06.28 HYUNDAI MOTOR CO LTD

AI summary

Disclosed is a power module capable of maximizing heat dissipation performance through application of a thick lead frame and a ceramic coating layer to upper and lower sides of a semiconductor device.