| 摘要 |
PURPOSE:To make it possible to align the position of a semiconductor substrate stably, by arranging a step part in the vicinity of an alignment mark, and selecting a signal having the best contrast from among a plurality of alignment signal outputs, which are obtained by changing the thickness of a resist film on the alignment mark. CONSTITUTION:A vertical step part 2, which is directed to an alignment mark 1, is provided in the vicinity of an alignment mark 1. The thickness of photoresist 3 is changed by more than half-wavelength of aligning light on the alignment mark 1 due to the step part 2. The aligning light is projected on a semiconductor substrate together. The position is detected with video signals having a scanning line group 4 which is orthogonal to the direction A-A. With respect to the signal outputs obtained from scanning lines SB, SC, SD and SE for positions B, C, D and E, the reflectivities are intactly used for the signal outputs. Only the signal from the scanning line SD which has the best contrast is selected from among the signals. Then the most stabilized position alignment is performed. |
