Abstract: An apparatus for the treatment of semi-conductor wafers is provided. The apparatus has a first valve mechanism for introducing different treatment fluids into a treatment tank from different reservoirs. At least one collection device is provided for collecting a treatment fluid after treatment of wafers therewith in the treatment tank. A second valve mechanism is provided for conveying at least a portion of the treatment fluid out of the collection device and to a respective reservoir. A rinsing mechanism is provided for rinsing the collection device.

Abstract: In a method of treating substrates a treatment fluid is fed into a collection vessel after treatment, at least a portion of the treatment fluid is withdrawn from the collection vessel and returned to respective reservoir and the collection vessel is rinsed before receiving another treatment fluid.