The invention discloses a plasma processing apparatus comprising a chamber lid, a chamber body and a support assembly. The chamber body, defining a processing volume for containing a plasma, for supporting the chamber lid. The chamber body is comprised of a chamber sidewall, a bottom wall and a liner assembly. The chamber sidewall and the bottom wall define a processing volume for containing a plasma. The liner assembly, disposed inside the processing volume, comprises of three or more slots formed thereon for providing an axial symmetric RF current path. The support assembly supports a substrate for processing within the chamber body. With the liner assembly with several symmetric slots, the present invention can prevent electromagnetic fields thereof from being azimuthal asymmetry.