Metrology becomes more and more a key function in mask making and development of new technologies. Due to the Sematech strategy a precision performance of less than 9 nm (3$sigma@) will be mandatory for the pattern placement and CD metrology tools for masks of the 0.25 $mu@m device generation. Performance data below 9 nm demonstrate the capability of today's metrology systems for this application. On phase shift masks (PSM) the pattern placement metrology tool should be able to measure the positions of the structures of both layers, the phase shifter and the chromium. Measurement data obtained with the LMS 2020 on embedded attenuated PSMs as well as results on Levenson type PSMs demonstrate the excellent applicability of optical metrology systems in this field. Cost of ownership (COO) of the metrology tool is another important issue to be reviewed. Currently more and more purchasing decisions among competing tools of similar performance are based on the COO comparison.
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