Patent ID: 7390735

Claim:
A process for forming packages of electronic components mounted on a substrate having a conductive coating, the electronic components and conductive substrate bonded by an electrically conductive metallic mixture, said package operable for extended periods of time at temperatures in excess of about 300° C. and under high voltage loads or current flows comprising: selecting at least a first, second, and third conductive metal with different melting temperatures, a first conductive metal having the highest melting temperature, the second conductive metal having a lower melting temperature, and the third conductive metal having an intermediate melting temperature such that a combination of said conductive metals form the electrically conductive metallic mixture, said electrically conductive metallic mixture having a melting point greater than the melting point of the second conductive metal, forming an electrically conductive coating of one or more of the first and third metals on the electronic components and the conductive substrate, placing a conductive metallic composition which comprises at least the second conductive metal between the coated electronic component and the coated substrate and clamping said assembly together, heating the clamped assembly to a temperature in excess of the melting point of the conductive metallic composition containing the second metal causing the conductive metal composition to melt, and maintaining said temperature for a sufficient period of time to allow diffusion of the material comprising the melted conductive metallic composition into the electrically conductive coatings on the electronic component and the substrate, and cooling the clamped assembly, the conductive material between the substrate and the electronic component comprising the electrically conductive metallic mixture that has a melting point greater than the melting point of the second conductive metal.