Power Module Substrate With Diffusion-Bonded Copper-Aluminum Circuit Layer

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Solution Overview

Problem

Conventional power module substrates face reliability issues with either heat cycle or power cycle due to the limitations of circuit layers made of aluminum or copper, where aluminum provides high heat cycle reliability but poor power cycle reliability, and copper provides high power cycle reliability but reduced heat cycle reliability, making it difficult to achieve both simultaneously.

Innovation Solution

A power module substrate with a circuit layer composed of a copper layer for efficient heat dissipation and an aluminum layer with solid phase diffusion bonding to copper, which absorbs heat stress and suppresses cracking, ensuring high reliability for both power and heat cycles by forming a diffusion layer with intermetallic compounds and maintaining thermal and electrical conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the circuit layer is made of an aluminum plate, then the deformation resistance is reduced, but the thermal conductivity deteriorates

Engineering Contradiction:

Improvedeformation resistanceVSAvoidthermal conductivity

Core Design Contradiction:

StrengthVSTemperature

Solution Approach 1:

The composite circuit layer uses aluminum and copper materials with complementary properties. The copper plate provides superior thermal conductivity for efficient heat dissipation, while the aluminum plate provides lower deformation resistance to absorb thermal expansion stress during heat cycles.

Inventive Principle:

Principle #40Composite materials

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 solution effectively reduces thermal resistance during power cycles and suppresses cracking in ceramic substrates during heat cycles, enhancing the overall reliability of the power module substrate with a heatsink, allowing for efficient heat dissipation and stable operation of semiconductor devices.

Implementation Method 1

an aluminum layer with solid phase diffusion bonding to copper, which absorbs heat stress and suppresses cracking

Methodology Applied

Scientific EffectSolid phase diffusion bonding: Diffusion Welding

Implementation Method 2

a circuit layer composed of a copper layer for efficient heat dissipation

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2833398B1Power module substrate, and method for manufacturing a power module substrate

Publication Date: 2018.06.20 MITSUBISHI MATERIALS CORP

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AI summary

A power module substrate includes a circuit layer 12, an aluminum layer 12A arranged on a surface of an insulation layer 11, and a copper layer 12B laminated on one side of the aluminum layer 12A. The aluminum layer 12A and the copper layer 12B are bonded together by solid phase diffusion bonding.