An apparatus and method for processing wafer-shaped articles comprises an array of nozzles that are stationary in use, and are individually controlled to simulate the action of a moving boom arm without the actual need for such an arm. Preferably three such arrays are provided, for dispensing three different types of liquid at various process stages. The computer control of the nozzle valves may cause only one nozzle of each array to be open at any given time, or may cause a pair of adjacent nozzles to be open simultaneously.