Selective Copper Plating in Silicon Dioxide Trenches with Metal Plasma Immersion Ion Implantation

ABSTRACTSelective deposition of copper in SiO2 trenches has been carried out using plasma immersion ion implantation and electroless Cu plating. To form the seed layer for electroless Cu plating on SiO2 , sputtered Pd and Si atoms were partially ionized by the Ar plasma and then deposited at bottoms of SiO2 trenches; Ar ions also assisted the ion beam mixing of the deposited Pd/Si films with the SiO2 substrate. We found a threshold Pd dose of 2–3×1014/cm2 is required to initiate the electroless plating of Cu. By controlling the Pd dose and the tapering angle of the SiO2 trench sidewalls, 1 μm wide Cu filled lines with flat surfaces suitable for planarized multilevel metallization were successfully fabricated.