Specific Process Knowledge/Characterization/Stylus Profiler Measurement Uncertainty: Difference between revisions
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For the Dektaks, we have in some cases seen that the scan noise is reproducible not only for scans in the same location, but even for scans in different locations on the stage, which must be due to some kind of dirt on the "feet" of the stage as they move across the optical flat. However in other cases, as in all the scans shown in the document above, the bowing of the scan varies even though the scan coordinates and sample are the same. The latter might be because the stage positioning is a little less accurate than for the P17 or because there is more environmental noise influencing the measurement. | For the Dektaks, we have in some cases seen that the scan noise is reproducible not only for scans in the same location, but even for scans in different locations on the stage, which must be due to some kind of dirt on the "feet" of the stage as they move across the optical flat. However in other cases, as in all the scans shown in the document above, the bowing of the scan varies even though the scan coordinates and sample are the same. The latter might be because the stage positioning is a little less accurate than for the P17 or because there is more environmental noise influencing the measurement. | ||
===How does the underlying scan noise affect the measurement accuracy=== | ===How does the underlying scan noise affect the measurement accuracy?=== | ||
The step determination will usually be better than the noise of the underlying scan - we don't expect an error in the measured step sizes as big as 30-60 nm. This comes down to removing some of the noise due to averaging parts of the scan during leveling and measuring. | The step determination will usually be better than the noise of the underlying scan - we don't expect an error in the measured step sizes as big as 30-60 nm. This comes down to removing some of the noise due to averaging parts of the scan during leveling and measuring. | ||