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We have established a measurement system for the direct calibration of energy density (dose) meters. It consists of beam-shaping objects, a beamsplitter, calibrated apertures, a beam profile monitor, an energy monitor, and a transfer standard. The 193 nm wavelength beam is homogenized by a fly's eye array producing a measured beam uniformity of 1.3 % (according to ISO 13694). This is well within the semiconductor manufacturing requirements for excimer laser beam uniformity of less than {+or-} 3%. Correlation measurements indicate the magnitude of spatial fluctuations within the homogenized beam profile have a correlation factor greater than 97%, validating our use of a beamsplitter. An analysis of confidence interval is approximately {+or-} 1.5%. The overall uncertainty is mainly dependent upon the uncertainty of the transfer standard's calibration factor; replacing the transfer standard with a primary standard, such as an electrically-calibrated calorimeter, should reduce the overall measurement uncertainty.
Laabs, H.
, Jones, R.
and Dowell, M.
(2002),
Dose Meter Calibration System for 193 nm, NEWRAD 2002, Gaithersburg, MD, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=30760
(Accessed October 17, 2025)