Characteristics of Copper thin film deposition and plasma properties in a DC/RF magnetron sputtering

Copper thin films are widely used as interconnects in semiconductor and display device, and are typically deposited using a sputtering system. As plasma sources for sputtering, DC and RF plasmas are employed, and they have different plasma properties such as electron density and electrode voltages. Although both plasma sources are commonly used, the correlation of plasma properties and deposition characteristics has not been comprehensively studied. In this study, we investigated the plasma properties and deposition characteristics of DC and RF plasmas in magnetron sputtering system. The plasma properties—electron density, electrode voltage, and optical emission intensity—were measured, and deposition characteristics such as surface morphology and deposition rate were investigated as well under varying working pressure and applied power. Consequently, significant differences in process results, such as deposition rate and surface morphology, were observed between the DC and RF sources, which were attributed to variations in plasma properties.