Positioning apparatus including a hydrostatic bearing for spacing apart a supporting surface and a guide surface

摘要

A base board supported on an X-Y stage or the like of an exposure apparatus includes a cylindrical fixed member. Porous pads held on the fixed member support the inner circumferential surface of a guide member provided as one body with a holding member for holding a wafer in a non- contact state. The base board is rotated around its central axis by a . theta. linear motor, and is reciprocated in the vertical direction by Z linear motors provided at an equal interval in the circumferential direction. Each of the Z linear motors and the &thgr; linear motor includes a rotor fixed to the holding board, and a stator that includes a coil fixed to the base board.