Specific Process Knowledge/Characterization/Dektak XTA: Difference between revisions
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===Adjust Measurement Settings for your Sample=== | ===Adjust Measurement Settings for your Sample=== | ||
Both the force setting and the scan speed are important: Too high force may compress a soft material like Al, Au or some polymers, while too low force may lead to the stylus "jumping" over features, especially if the scan speed is high. Too low scan speed may result in drift of the measurement and noise from vibrations while too high scan speed may mean that the stylus tip does not have time to reach the bottom of the features you are measuring and can also give rise to increased noise levels (see the [http://labmanager.dtu.dk/d4Show.php?id=2346&mach=304 DektakXT manual], Figure 3 for details). | Both the force setting and the scan speed are important: Too high force may compress a soft material like Al, Au or some polymers, while too low force may lead to the stylus "jumping" over features, especially if the scan speed is high. Too low scan speed may result in drift of the measurement and noise from vibrations while too high scan speed may mean that the stylus tip does not have time to reach the bottom of the features you are measuring and can also give rise to increased noise levels (see the [http://labmanager.dtu.dk/d4Show.php?id=2346&mach=304 DektakXT manual] on labmanager, Figure 3 for details). | ||
A sharp vertical step is easiest to measure. If the step is gradual or the surface is rough, it can be difficult to determine where to measure and how the scan should be leveled. Underlying sample curvature can also make it hard to level the scan. | A sharp vertical step is easiest to measure. If the step is gradual or the surface is rough, it can be difficult to determine where to measure and how the scan should be leveled. Underlying sample curvature can also make it hard to level the scan. | ||
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===Influence of Calibration Standard Uncertainty=== | ===Influence of Calibration Standard Uncertainty=== | ||
[[File:intrinsic step h error.png|350px|upright=2|alt=Axes with Measured values versus expected values and three lines illustrating measured=expected, plus two not-quite straight lines illustrating the confidence intervals growing as the values grow constrained by the calibration standard measurements. Two diamonds illustrate the location of the calibration sample measurement points. The plot's title says "Error from intrinsic uncertainty step height used for calibration".|right|thumb|Figure 1: Measurement uncertainty from uncertainty in the calibration standard (Not to scale). The linearity of the sensor means that the measurement error increases approximately linearly with the size of the feature being measured. The percentage-wise error on the smallest standard step is larger than on the bigger standard step, meaning the lines are not completely straight.]] | [[File:intrinsic step h error.png|350px|upright=2|alt=Axes with Measured values versus expected values and three lines illustrating measured=expected, plus two not-quite straight lines illustrating the confidence intervals growing as the values grow constrained by the calibration standard measurements. Two diamonds illustrate the location of the calibration sample measurement points. The plot's title says "Error from intrinsic uncertainty step height used for calibration".|right|thumb|Figure 1: Measurement uncertainty from uncertainty in the calibration standard (Not to scale). The linearity of the sensor means that the measurement error increases approximately linearly with the size of the feature being measured. The percentage-wise error on the smallest standard step is larger than on the bigger standard step, meaning the lines are not completely straight.]] | ||