A device for processing wafer-shaped articles comprises a closed process chamber providing a gas-tight enclosure, and a rotary chuck located within the closed process chamber. The closed process chamber comprises an annular duct surrounding the rotary chuck and extending along a first direction radially outwardly of the rotary chuck and obliquely to a rotary axis of the rotary chuck, from an inlet end that communicates with the rotary chuck to an outlet end that communicates with an exhaust duct. The annular duct comprises a duct section extending between the inlet and outlet ends that is defined by an inner chamber wall spaced apart from an outer chamber wall. The extent of the duct section along the first direction is at least twice a spacing of the inner and outer chamber walls throughout the duct section, as measured in a direction perpendicular to the first direction.