AlSiC Metal Matrix Composite Base Plates For High Power and High Reliability IGBT Modules

AlSiC (Aluminum Silicon Carbide), a metal matrix composite ideally suited for base plates material for insulated gate bipolar transistor (IGBT) is used in high-power traction, power control, Hybrid Electric Vehicle power systems, and fly-by-wire applications. AlSiC has been tested and meets the requirements of the Restriction of Hazardous Substances Directive of the European Parliament (RoHS compliant).

The low isotropic coefficient of thermal expansion (CTE) value of AlSiC-9 (8 ppm/°C: 30 – 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 redribbonlive 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 AlSiC systems have equal or improved thermal dissipation over Cu baseplate assemblies. ristomanager

In high power applications (> 1200 V/ 400 A), IGBT modules assembled with AlSiC baseplates are found to have a service reliability of many tens of thousands of thermal power cycles over Cu equivalent systems.

AlSiC is a lightweight material (1/3 that of Cu), which makes it an ideal cooler material for the weight-sensitive IGBT applications. AlSiC also has higher strength and stiffness than Cu, MATRIX CRACK which, combined with its lightweight nature, makes AlSiC assemblies more tolerant shock and vibration.

AlSiC near net-shape fabrication process both produces the composite material and fabricates the product geometry, allowing for the design of IGBT base plates with a dome profile. This geometry improves thermal interface contact with cold plates and coolers, adding to AlSiC’s advanced thermal management qualities. These are fabricated in standard of 190 mm x 140 mm, 140 mm x 130 mm and 140 mm x 70 mm base plate formats (shown) as well as custom formats.


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