SEMICONDUCTOR DEVICE

PURPOSE:To enable a reference point to be detected with high precision by a method wherein, within a planar region in the same level with one alignment mark, a focus adjusting region of beams is provided in contact with the alignment mark. CONSTITUTION:Within a planar region in the same level with one alignment mark 2, a focus adjusting region 7 of beams is provided in contact with the alignment mark 2. At this time, the focus adjusting region 7 of the beams for chip processing step is provided in contact with the L type alignment mark 2 as a high reflectance part 3 firstly to perform the focus adjustment using the focus adjusting region 7. On the other hand, the part 4 in low reflectance can be clearly discriminated from the focus adjusting region 7 in high reflectance. Next, the beam scanning step is performed in the alignment mark 2. Through these procedures, a reference point can be easily detected with high precision using focused beams.