Room-temperature copper etching based on a plasma–copper reaction

A promising room-temperature copper etching process is described. The copper thin film can be etched into a vertical profile at a high rate using a parallel-plate reactor under mild conditions. The key factor for the success of this process is a copper swelling phenomenon from the plasma–copper reaction. The reaction product has been identified as a crystalline copper chloride. Key parameters that influence the reaction process and the final copper profile have been studied. In addition to the plasma phase chemistry, ion bombardment plays a critical role in the process. Although results reported in this letter are based on the chlorine plasma, similar results can be obtained with other halogen gases. This process is potentially important to the fabrication of advanced microelectronic, storage, display, and optical devices.