An immersion lithography apparatus includes a lens system, an immersion hood, a wafer stage, an inspection system and a cleaning fluid supplier. The lens system is configured to project a pattern onto a wafer. The immersion hood is configured to confine an immersion fluid between the lens system and the wafer, and includes a peripheral hole configured to suck up the immersion fluid. The wafer stage is configured to position the wafer under the lens system. The inspection system is configured to detect whether there is contamination in the peripheral hole. The cleaning fluid supplier is coupled to the inspection system and configured to supply a cleaning fluid through the peripheral hole to remove the contamination, in which the inspection system and the cleaning fluid supplier are coupled to the wafer stage.