Oxidation study on as-bonded intermetallic of copper wire-aluminum bond pad metallization for electronic microchip

► 3 nm Al4Cu9 are found in sample prepared with Forming Gas ON. ► 15 nm mixed CuAl + CuAl2 are found in sample prepared with Forming Gas OFF. ► Voids are present at the bonding interfaces of both samples. ► Both samples have similar ball shear strength. ► Estimated interfacial temperature of as-bonded Forming Gas ON sample ∼437 °C.