Positioning device having three coil systems mutually enclosing angles of 120 DEG and lithographic device comprising such a positioning device

摘要

A positioning device is disclosed. The positioning device has a first part and a second part, the second part further has an object table. The second part may be displaced relative to the first part parallel to the XY-plane and may be rotated about the Z-axis by means of three motors. The motors are Lorentz type motors having a permanent magnet system and an electrical coil system cooperating therewith. The electrical coil systems each have windings which are substantially directed parallel to a main axis of the electrical coil system and perpendicular to the Z-axis. According to the invention, the main axis of each of the three motors encloses an angle of substantially 120 DEG with the main axis of each of the two other motors. In this manner, the points of application on the second part of the driving forces of the three motors are uniformly distributed relative to the second part, so that the driving forces can be uniformly transmitted to the object table by means of a relatively light and simple stiffening structure of the second part. In a particular embodiment of the positioning device, the main axes of the three motors are mutually arranged in a star-shaped configuration. In a second embodiment the main axes of the three motors are mutually arranged in a triangular configuration. The positioning device is used in a lithographic projection apparatus according to the invention for displacing a substrate table of the lithographic device relative to a focusing unit of the lithographic projection apparatus.