| 摘要 |
PURPOSE:To estimate error when detecting pattern and prevent erroneous shot on exposure by operator's judgment by detecting the fluctuation of quantity of light of illuminating light for detecting pattern. CONSTITUTION:The detection light received by the detector 32 is fed to the alignment signal analysis circuit 36 to obtain an amount of misalignment of reticle R and wafer W and to output the information to the CPU 42. One part of laser light LA which has passed through the half mirror 40 is output to the circuit 46 as a noise signal, where required noise information is obtained and the information is output to the CPU 42. The CPU 42 judges whether it is possible to perform alignment from the information obtained from the circuit 46 and gives warning by the indicator 48 or warning lamp 50 if the specified amount of noise is exceeded or performs alignment being based on the information from the alignment signal analysis circuit if the noise is below the specified amount. |
