Specific Process Knowledge/Characterization/Dektak XTA: Difference between revisions
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To estimate the overall accuracy of the profiler's measurements you can convolute these various sources of error. The error sources are shown graphically in Figure 2 for measuring the small standard step with the DektakXT's smallest range. You can see an uncertainty budget for the DektakXT measurements here (''made by Rebecca Ettlinger''): [[Media:Uncertainty budget Dektak rev.xlsx |Uncertainty budget Dektak rev.xlsx]]. It is based on the assumption that all the error sources are independent and can therefore be added by the sum of squares method. | To estimate the overall accuracy of the profiler's measurements you can convolute these various sources of error. The error sources are shown graphically in Figure 2 for measuring the small standard step with the DektakXT's smallest range. You can see an uncertainty budget for the DektakXT measurements here (''made by Rebecca Ettlinger''): [[Media:Uncertainty budget Dektak rev.xlsx |Uncertainty budget Dektak rev.xlsx]]. It is based on the assumption that all the error sources are independent and can therefore be added by the sum of squares method. | ||
The resulting error calculation for the DektakXT of a 1 µm very well defined standard step is about 2 % (as the uncertainty on the calibration standard dominates), while for a very well defined step of 25 µm the cumulative error is about 0.7-1 % | The resulting error calculation for the DektakXT of a 1 µm very well defined standard step is about 2 % (as the uncertainty on the calibration standard dominates), while for a very well defined step of 25 µm the cumulative error is about 0.7-1 %. However, in real devices the random error will often be much larger than for our standard samples and so the real confidence interval will be larger. | ||
To calculate the accuracy of your particular measurement, you should repeat the measurement several times and estimate the standard deviation. If the scatter is quite small you can try to calculate the total error on your measurement using the sum of squares method to combine the intrinsic step height error, the QC error and the random scatter error. If the scatter of your measurements is large that will be the dominant source of error in your measurement and you can safely ignore the other contributions. | To calculate the accuracy of your particular measurement, you should repeat the measurement several times and estimate the standard deviation. If the scatter is quite small you can try to calculate the total error on your measurement using the sum of squares method to combine the intrinsic step height error, the QC error and the random scatter error. If the scatter of your measurements is large that will be the dominant source of error in your measurement and you can safely ignore the other contributions. | ||
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