| 摘要 |
PURPOSE:To correct deviation of a maximum light intensity value due to a limit of fineness of a diffraction grating pattern, by adding an offset value to the maximum value in distribution of peak intensity values of collected light when a gap between a mask and a wafer is registered. CONSTITUTION:Registration between a mask 11 and a wafer 12 is performed manually in a rough manner. Then, one of four alignment marks is irradiated with laser light. A stage S is moved by an X-Y driver 22 while a scanner driver 23 is manipulated so that a peak value of light intensity is obtained and an FZP is registered in the X-or Y-direction with diffraction grating. This general control is performed by a microcomputer while the light intensity is monitored by a photodiode 7. Registration in the Z-direction, namely registration of a gap is performed by a piezoelectric element P controller by a piezocontroller 21. The maximum intensity value is obtained by monitoring the light intensities by means of the photodiode 7 under the control of the microcomputer 20. An offset value which has been previously calculated and inputted to the microcomputer is added to the maximum value thus obtained. |
