- Base plate

The base plate, as the foundation and heat conductor of power modules, also has the strict material requirement, which should have characteristics of excellent thermal conductivity and similar CTE with the substrate [34]. Table 4 shows the thermal mechanical attributes of possible materials for the base plate. CTE of Cu and Al are much higher than that of AlN (only 4.5 ppm/◦C), while CTE of metal matrix composites with Mo and Cu is close to that of AlN. The thermal conductivity of metal matrix composites makes these materials have excellent heat dissipation property. With these advantages, the metal matrix composite is an excellent choice for power modules to endure in a high-temperature environment. Due to the adjustable CTE from 6.5 to 9.5 ppm/◦C, and relatively high thermal conductivity with the range of 170–200 W/<sup>m</sup>·K, AlSiC is also an excellent material to constitute base plate.


**Table 4.** The thermal mechanical attributes of materials for the base plate.
