New method for producing power electronic circuit boards by cold-gas spraying and investigation of adhesion mechanisms

Ceramic substrates for power electronic circuits or integrated components are usually metallised by cost-intensive thermal processes. Simple, flexible and cost-effective solutions are increasingly demanded for integrated power electronic devices. Cold gas spraying (CGS) can deliver these demands. It is employed to produce dense, well adherent and oxide free coatings with properties comparable to the respective bulk material. The CGS-metallisation of non-conductive parts for power electronic devices permits a direct assembly and contacting of semi-conductors. rially available Al2O3 substrates are first CGS-coated with aluminium, which acts as an adhesive layer. In a second step, the aluminium layer is coated with copper, which exhibits good electric properties. The conductive structure on the ceramic is achieved by using a laser cut steel template, which allows for a minimal circuit width of about 250 μm. er to clarify the adhesion mechanisms of cold-gas sprayed aluminium on alumina coated samples were subjected to micro-structural characterisation with scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM) and electron backscatter diffraction (EBSD).