Two-dimensional precise positioning device for use in a semiconductor manufacturing apparatus

A precision positioning device particularly adapted for a semiconductor manufacturing operation comprising:

• a loading table;
• an armature, said armature being disposed on said loading table;
• a magnetic field group formed from a plurality of magnetic fields disposed on a plane in a two-dimensional array, the centers of the magnetic fields of the array being separated by an equal period, the magnetic fields of the array being disposed perpendicular to the plane and adjacent magnetic fields being directed in alternate directions;
• and
• a first coil group comprising at least first, second, third and fourth coils having a fixed dimensional relationship:
• (i) each coil of said first coil group being provided with an outer dimension approximately equal to 3/2 of the period of the array of magnetic fields;
• (ii) each coil of said first coil group being provided with a winding width approximately equal to 1/2 of the period of the array of magnetic fields;
• (iii) said second coil of said first coil group being displaced along the plane from said first coil by an odd number multiple of approximately 1/2 of the period of the array of magnetic fields;
• (iv) said third coil of said first coil group being displaced along the plane in a direction orthogonal to the direction of displacement of said second coil by an odd number multiple of approximately 1/2 of the period of the array of magnetic fields;
• and
• (v) said fourth coil of said first coil group being displaced along the plane from both said second and said third coils by an odd number multiple of approximately 1/2 the period of the array of magnetic fields;
• one of said magnetic field groups and said first coil group being disposed on said armature and freely movable along the plane.