METHOD FOR IN-SITU ABERRATION MEASUREMENT OF OPTICAL IMAGING SYSTEM IN LITHOGRAPHIC TOOLS

摘要

The present invention has disclosed a method for in-situ aberration measurement in an optical imaging system of lithographic tools, which comprises the steps of: imaging the reticle pattern by the beams transmitting through the reticle via the optical imaging system; using particular tools to measure plural groups of linewidths by modifying the intensity distribution at the exit pupil plane of the optical imaging system; calculating the asymmetry and ununiformity of the linewidths and calculating the aberrations of the optical imaging system. The present method for aberration measurement can simplify the process of measurement; increase the measurement accuracy of the parameters of image quality; and reduce the time of measurement.