| 摘要 |
PURPOSE:To prevent the generation of an error in detection of positioning mark by a method wherein the range of selection of signal-noise ratio of the signal with which the positioning mark on a wafer is detected by an electron beam is set based on the signal obtained by scanning an electron beam on the pattern located on the wafer. CONSTITUTION:The reference value of the signal-noise ratio of the signal with which a positioning mark is detected by an electron beam is calculated from the signal obtained by scanning an electron beam 5 on the optimum pattern located on a wafer 1, and the selecting range of the signal-noise ratio of the signal of a positioning mark detecting signal is established. When an exposing process is going to be performed on the signals obtained by scanning an electron beam on the mark 3 of a chip 2, the signals having too small or too large signal-noise ratio which is beyond the range of selection are excluded, and the mark position is distinguished using the signals within the range of selection. For example, a large peak appears when a substance having different atomic weight is adhered to the surface of the wafer, and a little peak is generated by the recesses and protrusions on the wafer surface, but the erroneous recognition of the above as a positioning mark can be prevented remarkably by properly selecting the signal. |
