The method and the apparatus prevents the deformation of a substrate, e.g. a wafer, supported with its edge area or periphery at a support or chuck, and also avoids the damage and/or contamination of the active area of the substrate. In particular, the substrate is mechanically supported at its peripheral or edge portion, namely in the non-active area of the substrate, only; an additional non-mechanical extended support is provided in the active area by a gas cushion. The gas cushion is generated by a controllable nozzle or purge for a distinct and controlled compensation of the downward deflection of the substrate.