US Patent 11822260 Apparatus for removing residue of EUV light source vessel

An apparatus for removing a residue of an EUV light source vessel including an internal side surface having a curved surface is provided. The apparatus includes a frame portion configured to be disposed on a bottom surface of an EUV light source vessel and a head portion above the frame portion. The head portion is configured to be rotatably moved on a circular trajectory while maintaining a desired (and/or alternatively predetermined) distance from the curved surface of the EUV light source vessel. The head portion may have a heating member configured to emit heat toward the curved surface of the EUV light source vessel. The heating member may have a shape curved in an arc corresponding to a portion of the circular trajectory.