POSITIONING DEVICE HAVING THREE COIL SYSTEMS MUTUALLY ENCLOSING ANGLES OF 120 DEG , AND LITHOGRAPHIC DEVICE COMPRISING SUCH A POSITIONING DEVICE

摘要

The invention relates to a positioning device (3) comprising a first part (33) and a second part (35) having an object table (5). The second part can be displaced relative to the first part parallel to an X-direction and parallel to a Y-direction which is perpendicular to the X-direction and can be rotated relative to the first part about an axis of rotation (73) directed parallel to a Z-direction which is perpendicular to the X-direction and perpendicular to the Y-direction by means of three motors (75, 77, 79) which each comprises a permanent-magnet system (97, 99, 101) and an electrical-coil system (81, 83, 85) cooperating with the permanent-magnet system. The electrical-coil systems each comprises windings which are mainly directed parallel to a main axis (87, 89, 91) of the electrical-coil system which is directed perpendicularly to the Z-direction. 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 (119) of the second part. In a special embodiment of the positioning device, the main axes of the three motors are mutually arranged in a star-shaped configuration. In a further embodiment of the positioning device (3'), the main axes (87', 89', 91') of the three motors (75', 77', 79') are mutually arranged in a triangular configuration. The positioning device is used in a lithographic device according to the invention for displacing a substrate table (5) of the lithographic device relative to a focusing unit of the lithographic device.