A substrate measuring stage of this type includes a mounting board on which a substrate is mounted and a plurality of support pins provided to penetrate through the mounting board. The substrate measuring stage is structured so that the mounting board is fixed and the support pins are moved or both the mounting board and the support pins are moved and the support pins protrude from below the mounting board.
However, the substrate measuring stage configured to move the support pins has a problem of poor reproducibility of height positions of the support pins in every measurement.
Furthermore, the substrate measuring stage configured to adjust the height positions of the respective support pins has a following problem. It is difficult to locate tip ends of the respective support pins to be flat with one another. To solve the problem, there are proposed a substrate measuring stage structured so that a plurality of support pins is fixed to a common member and all the support pins are vertically moved simultaneously, as disclosed in, for example, Patent documents 1 and 2.
However, it is difficult to move up a plurality of support pins in parallel and the support pins are temporally offset at the time of contacting with the substrate. As a result, positional displacement occurs between the substrate mounted on the mounting board and the substrate supported on the support pins at least in an XY plane (in a horizontal direction).
Moreover, to compare a measurement result of a thickness or the like with that of a curve, it is considered to be necessary to set a measurement position for measurement of the thickness or the like equal in height to that for measurement of the curve. This is because focuses of a thickness measuring system and a curve measuring system deviate from each other to adversely influence measurement results if the substrate on the mounting board differs in height from the substrate on the support pins. If such a thing occurs, it is necessary to adjust the heights of the support pins to adjust the height of the substrate to be identical to the height at which the substrate is mounted on the mounting board after the substrate is supported on the support pins when the position of the substrate is moved from the position on the mounting board to the position on the support pins.
Nevertheless, as described, the substrate disadvantageously deviates in the horizontal direction during moving of the position of the substrate and the substrate measuring stage structured to move the support pins is disadvantageously poor in height reproducibility.
[Patent document 1] Japanese Unexamined Patent Publication No. 1994-97269
[Patent document 2] Japanese Unexamined Patent Publication No. 2006-332587