Jens Gobrecht

Directly Bonded Copper Metallization of AℓN Substrates for Power Hybrids

Aluminum nitride (AlN) ceramic is emerging as an attractive substrate material for high performance heat sinking in hybrid circuits be -cause of its high thermal conductivity. We report on the application of the direct bonding technique for Cu on AlN substrates. For successful bonds, the surface of the AlN has to be oxidized. Oxidation rates are reported and the oxide morphology is analyzed. The peel strength of the Cu sheet depends on oxide thickness, growth method and Cu-type used. Under optimum conditions the peel strength exceeds 50 N/cm. A detailed analysis using optical microscopy as well as SEM, STEM, EDX, and electron diffraction techniques of the AlN/Al 2 O 3 /Cu interface is carried out.