| 摘要 |
PURPOSE:To enable detection with high precision by a method wherein the minimum values are successively detected until the change in physical properties of a photoresist layer in case of exposure to light is stabilized so that a means to assume the electric signal component corresponding to the edge of alignment mark to be the component with stabilized minimum value may be provided. CONSTITUTION:When an alignment mark 12 buried in a photoresist layer 23 is illuminated, the photoresist layer 23 covering the alignment mark 12 is exposed to light changing the physical properties thereof so that the alignment mark detection signal VDIN transmitted from alignment mark signal forming means 18, 19 may change the electric signal components correspondingly to the change of photoresist layer 23. The electric signal component corresponding to the edge face 12B of alignment mark 12 out of those components transmitted from the alignment mark signal means 18, 19 constantly represents the minimum value and the position represented by this minimum value can be assumed to be the position of alignment mark 12. Through these procedures, the alignment mark 12 can be detected under no substantial influence of the photoresist 23 to perform the alignment with high precision. |
