The objective of this proposal was to develop double side cooled packaging solutions for semiconductors eliminating the use of inherently unreliable aluminium wire bonds and replacing with seamless contacting techniques to either side of the active semiconductor thereby providing a very reliable low thermal resistance, low inductance contact. The solutions developed using innovative additive laser machining and lost wax techniques was applicable to not only todays active components but tomorrows also. The constructional methods developed to package the active devices were inherently low cost compared to those associated with today's double side cooled structures.
The double side cooled structures emanating out of this project were extremely manufacturable and will offer the ultimate in long-term reliability required by the aerospace industry and facilitated the use of higher temperature devices operating at higher current densities and frequencies i.e. SiC. In the event of system over currents the devices designed within the project are intended to fail short circuit. The ability for Europe to have an indigenous semiconductor supplier able to supply advanced components packaged in a unique thermal efficient, compact and reliable manner will give the EUs systems suppliers a significant competitive edge in aerospace and other advanced applications. A 10KW silicon carbide inverter based on specification supplied by the SGOs was envisaged.
The resultant module consisted of two single switches to form a half bridge configuration, each of which had four SiC-MOSFET and four matched SiC-SBD. The module outlines a new packaging concept which included silver sintering, a silicon nitride substrate, no wire bonds, no baseplate and a flexible PCB foil with integrated terminals. By using the newly developed SiC-based chip set and the new packaging technology the temperature of the SiC power module could be operated at 200 ºC as per the specification.
The second main area was focused on a higher voltage option where a larger standoff is necessary, this used technology, based on an electroforming process, Selective Layer Additive Manufacture Process. This novel approach was based on the 2000-year-old lost wax process incorporating a low temperature plating process to create an electroformed shell.