Example embodiments relate to a method of treating a substrate after performing a cleaning step with a liquid chemical in a single substrate spin cleaner. A method of treating a substrate according to example embodiments may include forming a film of deionized water on a surface of the substrate during rinsing, and drying the substrate by supplying a drying gas to the water film on the surface of the substrate. When rinsing the substrate, the rotating speed of the substrate may be reduced to about 50 rpm or less to form a film of water on the surface of the substrate. The film of water may shield the surface of the substrate from direct exposure to atmospheric air. The film of water may be maintained on the surface of the substrate when commencing the supply of the drying gas. Consequently, the number of water marks on the dried substrate may be reduced or prevented.