US Patent 7187432 Holding system, exposure apparatus, and device manufacturing method

A holding system for holding an object from above, against gravity. The holding system includes at least one holding portion adapted to be in contact with the object, to hold the object from above, at least one attracting portion for attracting a limited portion of the object upwardly, without contact thereto, and a gap measuring unit for measuring a gap between the object and the at least one attracting portion. The attraction force of the attracting portion is controlled on the basis of the measurement made by the gap measuring unit.