Specific Process Knowledge/Characterization/Profiler: Difference between revisions
| Line 93: | Line 93: | ||
====Total uncertainty==== | ====Total uncertainty==== | ||
[[File:Error probability distributions.png| | [[File:Error probability distributions.png|upright=2|alt=Four different probability distributions that contribute to the total error on the Dektak measurement for the 6.5 micron range. By far the widest distribution is the one from the error on the calibration standard, which is a Gaussian. The others are the non-Gaussian spread of the average measurement of the calibration standard height, which cuts off at the QC limits, the resolution, which is a very narrow uniform distribution, and the spread of measurement values for a given step being measured, which is a Gaussian whose width depends on the step in question.|right|thumb|The probability distributions of the main sources of error that are convoluted to create the total error on a Dektak measurement.]] | ||
To estimate the accuracy of the Dektak's measurements we have to combine the error of the calibration with the error from the limit on the resolution and the scatter of repeated measurements. This is shown graphically on the right. You can see an uncertainty budget for the Dektak measurements here (made by Rebecca Ettlinger in 2020): [[Media:uncertainty budget dektaks.xlsx]]. It is based on the procedure described [https://www.nde-ed.org/GeneralResources/Uncertainty/Combined.htm here]. | To estimate the accuracy of the Dektak's measurements we have to combine the error of the calibration with the error from the limit on the resolution and the scatter of repeated measurements. This is shown graphically on the right. You can see an uncertainty budget for the Dektak measurements here (made by Rebecca Ettlinger in 2020): [[Media:uncertainty budget dektaks.xlsx]]. It is based on the procedure described [https://www.nde-ed.org/GeneralResources/Uncertainty/Combined.htm here]. | ||