Specific Process Knowledge/Characterization/Profiler: Difference between revisions
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Nanolab staff check the instrument's measurement accuracy with a standard step height of 9160 Å for the 65 kÅ range and 24.865 µm for the larger ranges. The 95 % confidence intervals for the standards are 300 Å for the 9160 Å standard and 0.15 µm for the 24.865 µm standard. If the control measurement is beyond the limit set in our Quality Control procedure, the instrument is calibrated and the users informed (see LabManager for details on the [http://labmanager.dtu.dk/d4Show.php?id=2493&mach=304 control instruction] and the [https://labmanager.dtu.dk/view_binary.php?type=data&mach=304 control measurement data]). | Nanolab staff check the instrument's measurement accuracy with a standard step height of 9160 Å for the 65 kÅ range and 24.865 µm for the larger ranges. The 95 % confidence intervals for the standards are 300 Å for the 9160 Å standard and 0.15 µm for the 24.865 µm standard. If the control measurement is beyond the limit set in our Quality Control procedure, the instrument is calibrated and the users informed (see LabManager for details on the [http://labmanager.dtu.dk/d4Show.php?id=2493&mach=304 control instruction] and the [https://labmanager.dtu.dk/view_binary.php?type=data&mach=304 control measurement data]). | ||
The size of the calibration standard confidence intervals mean that the measurement uncertainty is much more significant for very shallow steps below 500-1000 nm than for steps in the micron range: The 95 % confidence interval in the 65 kÅ range is obviously at least ± | The size of the calibration standard confidence intervals mean that the measurement uncertainty is much more significant for very shallow steps below 500-1000 nm than for steps in the micron range: The 95 % confidence interval in the 65 kÅ range is obviously at least ± 30nm, so measuring a 100-200 nm step will have a large error percentage-wise. Note that this error (from the calibration standard) is systematic. The random error associated with repeated measurements is usually smaller (perhaps ± 5 nm). One can therefore measure shallow steps to compare samples even if the absolute numbers are not very reliable. | ||
====Total uncertainty budget==== | ====Total uncertainty budget==== | ||