Achieving the specifications of line width roughness (LWR), sensitivity and resolution of wafer resist is one of the top challenges of bringing extreme ultraviolet lithography (EUVL) into high volume manufacturing. At the same time, EUV mask LWR is set on very ambitious target value from ITRS [1] because mask LWR would contribute to wafer resist LWR more strongly than that of ArF lithography due to dramatic decrease of wavelength. Mutual relation between mask and wafer resist LWR has been discussed [2] [3] but not frequently, so standardization of mask LWR measurement is not fixed. SEM image analysis is common to measure mask LWR but the value depends on measurement parameters such as segment length of pattern edge. In this paper, optimum measurement conditions with SEM will be investigated and discussed using SEM images of actual mask and aerial simulation. And also we will report development status of actual mask LWR.
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