AlSiC

AlSiC, pronounced "alsick", is a metal matrix composite consisting of aluminium matrix with silicon carbide particles. It has high thermal conductivity (180–200 W/m K), and its thermal expansion can be adjusted to match other materials, e.g. silicon and gallium arsenide chips and various ceramics. It is chiefly used in microelectronics as substrate for power semiconductor devices and high density multi-chip modules, where it aids with removal of waste heat.

Several variants exist:

AlSiC composites are suitable replacements for copper-molybdenum (CuMo) and copper-tungsten (CuW) alloys; they have about 1/3 the weight of copper, 1/5 of CuMo, and 1/6 of CuW, making them suitable for weight-sensitive applications; they are also stronger and stiffer than copper. They are stiff, lightweight, and strong. They can be used as heatsinks, substrates for power electronics (e.g. IGBTs and high-power LEDs), heat spreaders, housings for electronics, and lids for chips, e.g. microprocessors and ASICs. Metal and ceramic inserts and channels for a coolant can be integrated into the parts during manufacture. AlSiC composites can be produced relatively inexpensively (USD 2-4/lb in large series); the dedicated tooling however causes large up-front expenses, making AlSiC more suitable for mature designs.Heat pipes can be embedded into AlSiC, raising effective heat conductivity to 500–800 W/m K.

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