A plasma processing system includes a radio-frequency (RF) power source unit configured to generate three RF powers; a process chamber to which a process gas supplied and to which the RF powers are applied to generate a plasma; and an impedance matcher between the RF power source unit and the process chamber, the impedance matcher configured to adjust an impedance. The RF power source unit may include a first RF power source connected to a first electrode located in a lower portion of the process chamber to apply a first RF power having a first frequency, a second RF power source connected to the first electrode and to apply a second RF power having a second frequency, and a third RF power source connected to a second electrode located in an upper portion of the process chamber and to apply a third RF power having a third frequency.