Embodiments of the inventive concept provide a substrate processing apparatus. The substrate treating apparatus comprises a process treating unit providing a treating space performed treating the substrate; a plasma generating unit generating the plasma discharging a process gas, and supplying the plasma to the treating space. The plasma generating unit provides a plasma chamber having a generating space of the plasma; an antenna wound to surround the plasma chamber outside the plasma chamber; a first coating film covering inside walls of the plasma chamber and comprising yttrium fluoride (YF3).