Abstract: Above a substrate mounted on rollers, an upper board is prepared a predetermined distance apart from the substrate. A pipe fills a space between the upper board and the substrate with washing water by supplying the washing water at a predetermined flow rate. A washing water layer is formed evenly on an upper surface of the substrate when the substrate passes below the upper board. Below the substrate, a lower board is prepared a predetermined distance apart from the substrate. A pipe fills a space between the lower board and the substrate with the washing water by supplying the washing water at a predetermined flow rate. A washing water layer is formed evenly on a lower surface of the substrate when the substrate passes above the lower board. The air emitted from an air knife is sprayed to the upper/lower surface of the substrate slantingly at a predetermined incident angle in an opposite direction of a substrate moving direction.

Abstract: Thin substrate plates are transferred in a horizontal or tilted posture on and by a substrate transfer means. Provided by a substrate transfer path is an air knife nozzle for scraping and drying off a liquid successively from surfaces of the substrates on the substrate transfer means. The air knife nozzle is located substantially at a uniform distance across a drying surface of a substrate plate on the transfer means. The air knife nozzle is provided with a slit-like nozzle hole to spurt jet air to the drying surface from an angular direction relative to a direction perpendicular to the substrate transfer direction and to sweep the substrate across the entire width of the drying surface and with a predetermined angle of incidence relative to the substrate transfer direction.