| 摘要 |
<p>PURPOSE:To improve the position alignment precision of a semiconductor wafer or a photomask on an aligner up to the order of nanometer (nm). CONSTITUTION:An uneven mark 30 for position alignment is formed on the rear 1b side of a wafer 1, and scanned by using a probe 6 of an atomic force microscope (AFM) or a probe 9 of a scanning tunnelling electron microscope (STM). Since the form and the position of the uneven mark 30 are not affected by a process performed on the front 1a side, high precision detection is always enabled. The pattern density of the uneven mark 30 is increased toward the center of symmetry, and the change periods of interatomic force and tunnel current are shortened in the vicinity of the center, so that the optimum position can be very easily determined. On a photomask substrate, the uneven mark is formed by working a Cr light shielding film, and similarly can be detected.</p> |
