PURPOSE: A plasma processing apparatus is provided to balance horizontal symmetry of plasma density in a reaction space of a process chamber through a balance member, thereby forming a uniform thin film on a substrate. CONSTITUTION: A process chamber provides a reaction space. A substrate support unit is installed in the process chamber to support a substrate. An antenna(140) is installed in the process chamber to face the substrate support unit. The antenna generates plasma in the reaction space using RF power. A balance member(146) balances horizontal symmetry of plasma density generated in the reaction space.
