CPS Offers AlSiC-9 Baseplates For IGBT Power Modules
CPS Technologies Corp. introduced its AlSiC (Aluminum Silicon Carbide), a metal matrix composite ideally suited for baseplates material for insulated gate bipolar transistor (IGBT) used in high-power traction, power control, and motor controller (motion control) applications.
According to the company, more than half of the electricity consumed in the world is used to drive motors of some kind, whether they are for commercial, industrial or military applications. Motor Control IGBT Power Modules need to meet the energy efficiency and reliability standards for today’s variable speed motor control applications. Both factors affect the cost of energy over time. The switching for motor speed controls thermally stresses the IGBT power modules.
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 power modules for motor control applications. The AlSiC CTE match reduces the mechanical stresses on IGBT die and substrates that is induced by thermal power cycling (variable speed motors, surges, etc.), which is said to improve 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.
According to the company, in high power motor control 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 a suitable cooler material for the weight-sensitive IGBT applications (aircraft actuators, control systems, etc.). AlSiC is also said to have a higher strength and stiffness than Cu, which, combined with its lightweight nature, makes AlSiC assemblies more tolerant to shock and vibration.
The CPS AlSiC near net-shape fabrication process both produces the composite material and fabricates the product geometry, allowing for the design of IGBT baseplates with a dome profile. This geometry is said to improve thermal interface contact with cold plates and coolers, adding to AlSiC’s advanced thermal management qualities. CPS fabricates standard of 190 x 140mm, 140 x 130mm and 140 x 70mm baseplate formats as well as custom size configurations. AlSiC has been tested and meets the requirements of the Restriction of Hazardous Substances Directive of the European Parliament (RoHS compliant).
