SUBSTRATE PROCESSING APPARATUS AND METHOD

PROBLEM TO BE SOLVED: To downsize a substrate processing apparatus and to easily form a thin liquid film on a substrate.SOLUTION: A substrate processing apparatus 1 includes: a chamber 7; a humidity control unit 81 for controlling humidity inside the chamber 7; and a cooling medium supply unit 4 for supplying a cooling gas toward a substrate 9. The cooling gas supplied toward a center portion of an upper surface 91 of the substrate 9 is expanded over an entire surface of the upper surface 91 by rotation of the substrate 9 to entirely cool the substrate 9, so that a water content (pure water) in a processing gas in the chamber 7 is condensed into droplets on the upper surface 91 of the substrate 9 to form a thin liquid film of the pure water entirely covering the upper surface 91. When the formation of the liquid film is completed, the reciprocating movement of a cooling gas nozzle 41 between the center portion and an outer edge portion of the substrate 9 allows the cooling gas to be entirely supplied to the upper surface 91 of the substrate 9 to freeze the liquid film. A structure for discharging the liquid for the liquid film formation toward the upper surface 91 of the substrate 9 is omitted, thereby allowing the substrate processing apparatus 1 to be downsized and allowing the thin liquid film to be easily formed on the substrate 9.