LAUSR

Alternating between the underpotential deposition (UPD) of Co and surface-limited redox replacement (SLRR) of Cu enables the growth of a Cu(Co) film in a layer-by-layer manner. The technique is essential for fabricating Cu interconnects in nano-sized microelectronics. This work presents a technique to control the composition of a Cu(Co) film by controlling the time of the open circuit potential (OCP) during the SLRR of Cu because a longer OCP time results in a greater replacement of the UPD-Co by Cu. The results of this work further show that the addition of H3BO3 to the Co electrolyte enhances the deposition of UPD-Co without the formation of Co(OH)2. The crystalline structure of the resultant film is examined by X-ray diffraction to confirm the formation of the Cu(Co) film. The effect of the addition of H3BO3 to the Co electrolyte on the formation of the Cu(Co) film via the proposed process is demonstrated.