AlSiC metal matrix composite base plates

June 20, 2008

CPS Corporation has developed its AlSiC (aluminum silicon carbide) metal matrix composite, suited for base plates material for insulated gate bipolar transistor (IGBT) used in high-power traction, power control, hybrid electric vehicle power systems and fly-by-wire applications. It has been tested and is RoHS compliant.

The low isotropic coefficient of thermal expansion (CTE) value of AlSiC-9 (8 ppm/°C: 30°C - 100°C) is compatible with the thermal expansion value of the die or substrate used in IGBT applications. The AlSiC CTE match reduces the mechanical stresses on IGBT die and substrates that is induced by thermal power cycling, which improves reliability of substrate attachment and reduces die-cracking failures.

The device compatible AlSiC CTE eliminates the need for stress compensation material layers that are required in Cu (CTE = 17ppm/°C) baseplate assemblies. Elimination of stress compensation materials simplifies assembly and reduces the thermal resistance for AlSiC systems so that they have equal or improved thermal dissipation over Cu baseplate assemblies, the company says. AlSiC weighs 1/3 that of copper, which makes it a suitable cooler material for weight-sensitive IGBT applications. CPS fabricates standard of 190 mm x 140 mm, 140 mm x 130 mm and 140 mm x 70 mm base plate formats as well as custom formats.
http://www.alsic.com