| 摘要 |
The present invention provides three 2D heads (60i, 60ia, 60ib (i=1-4)) at the corner section of each of the first, second, third and fourth quadrants which originate at the center on the surface of a stage (WST1). While powering the stage (WST1), the position of the stage (WST1) is measured by using, of the four heads (60i (i=1, 2, 3, 4), the three heads (60i) facing a 2D grating (RG) of a scale plate (21) positioned above the stage (WST1). While powering, differential data for the measured values is captured pertaining to the measurement direction of the remaining two heads (60ia, 60ib) besides the heads (60i) among each set of three heads belonging to the head groups (61i) to which the three heads respectively belong. Using this differential data, the grid error in the measurement direction of the 2D grating (RG) is calibrated. |
