Copper based composite:L-Cop

Cu High thermal Conductive

Cu2O Low thermal expansive

Anna malaiIndustrial Engineering

Material Science

Introduction

ApplicationElectronic devices to achieve long life and reliable performance

High current power modulesTo reduce high shear stress at soldering joint

• Mismatch in coefficient of thermal expansion between ceramic substrate to Cu/Al base plate attachment

Silicon carbide reinforced aluminum SiC/Al• Difficult to machine due to high ceramic content

Cu/Mo & Cu/W Composite• Difficult to manufacture – Sintering at above 2000°C

L-Cop: powder-metallurgy process

Electrolytic Cu powder & and CuO powder are used

Cu2O is thermally stable than CuO and in elevated temperature stable phase of Cu & Cu2O can be readily achieved in sintering process due to internal oxidation of Cu & CuO.

It is possible to distribute the Cu phase and Cu2O phase uniformly by Cu + CuO Cu2O reaction Fabricated into preform

using a press

Ball Milling

Microstructure in Powder metallurgy process

Thermal Conductivity Vs. Coefficient of Thermal Expansion

Hot Extrusion Process6500 Mpa Cold Isostatic press

Subsequent hot extrusion.

Improves Heat conductivity, Coefficient of thermal expansion & Density

Extruded L-Cop Vs. Sintered L-Cop

Extruded L-Cop application

References

www.hitachi-cable.co.jp/en/review/22/pdf/h-13.pdf

www.howstuffworks.com