The invention relates to an apparatus and nozzle head for processing a surface of a substrate. The apparatus includes a substrate support mechanism for supporting the substrate on a substrate support plane in a process zone, a nozzle head for subjecting the surface of the substrate to successive surface reactions of at least a first precursor and a second precursor and a nozzle head support mechanism for supporting the nozzle head at a predetermined distance from the substrate support plane. The nozzle head support mechanism includes a nozzle head support surface and, that the nozzle head is supported to the nozzle head support surface.