Abstract: A substrates-washing apparatus includes a process vessel in which washing solution is stored to wash a plurality of substrates, a boat for holding the substrates parallel to one another in the process vessel, solution supply openings formed in the bottom of the process vessel, a solution supply system communicated with the solution supply openings to supply washing solution into the process vessel through the solution supply openings, and a straightening plate arranged between the substrates held on the boat and the solution supply openings in the bottom of the process vessel and provided with a plurality of apertures through which washing solution passes. The apertures form plural lines in the longitudinal direction of the straightening plate, the apertures in each line are arranged to correspond to the substrates alternately, and the apertures in one line are shifted from those in the other adjacent line.

Abstract: A wafer drying apparatus incorporated in a semiconductor wafer cleaning system includes a bath for storing IPA. A heater for generating an IPA vapor is arranged on the bath. The bath is surrounded by a housing. The housing has opening portions at three positions. The opening portions are opened/closed by shutters. A sensor for detecting a fire and a nozzle for discharging CO.sub.2 gas into the bath are arranged around the bath. A plurality of wafers are held by a chuck of a convey robot and are conveyed from the outside of the housing into the housing via the opening portions. When a fire is detected by the sensor, the chuck immediately retreats from the housing, and the shutters are closed. Signals for closing the shutters are transmitted to shutter drive sources again 10 seconds after the fire is detected, and discharging of CO.sub.2 gas is started 20 seconds after the fire is detected.