The present invention provides an apparatus and method for cleaning substrates such as semiconductor wafers by sinking the substrates into cleaning fluids such as cleaning chemicals or rinsing liquids and then drying the substrates. The substrate clean and dry apparatus of present invention includes a process chamber comprising a cleaning chamber that carries the cleaning fluid and discharges at bottom the cleaning fluid; and a drying chamber above the cleaning chamber. The process chamber further includes a discharge device for evacuating the gas from the drying chamber, the gas supplied into the drying chamber. The discharge device is located between the cleaning chamber and the drying chamber, and evacuates the gas by force such that the gas is driven down vertically in the drying chamber. The substrate clean and dry apparatus of the present invention generates fairly vertical and uniform gas flows over the surfaces of substrates in the drying chamber, and also evacuates the gas rapidly from the drying chamber, thereby enhancing efficiency of the drying process.