摘要
In high-power-density power modules, where heavy Al wire bonding is prevalent, reliable top-side interconnection continues to be a critical bottleneck. When Al wire bonding onto copper (Cu) pads on direct bonded copper (DBC) substrates, typically a compatible surface metallization such as Ni/Au plating or organic solderability preservatives (OSP) prevents surface Cu oxides from forming. However, these oxidation protection schemes introduce increased costs or process complexity. In this study, an AlCl 3 /urea deep eutectic solvent (DES) electrolyte (molar ratio 1.3:1) is utilized to directly electrodeposit Al onto DBC Cu pads to provide an oxidation-resistant Al surface compatible with Al-Al wire bonding. Ultrasonic wedge bonding of 380 μm Al heavy wires demonstrates that the initially granular Al surface is effectively accommodated after electrodeposition, producing a flat and continuous bonded interface. Bonding tests demonstrate wire deformation of 1.3x wire diameter, sufficient to DVS 2811 guidelines, and shear residuals show failure originating within the Al wire/bonded Al rather than at the Al/Cu interface. These results provide the first experimental demonstration that electrodeposited Al on DBC Cu pads can serve as a practical metallization layer for heavy Al wire bonding in power-module packaging, offering a scalable alternative to vacuum-deposited Al and conventional oxidation finishes.