Specific Process Knowledge/Characterization/Sample imaging: Difference between revisions

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 Using the different options such as bright/dark field, polarizer or transmitted/reflected light one can find a better signal for a specific need. Some of them have a camera that allows you to capture and store images.
-One of the advantages of the optical microscopes is that they provide fast and easy accessible information about any sample without any kind of sample preparation. They do, however, also have some limitations.
+One of the advantages of the optical microscopes is that they provide fast and easy accessible information about any sample without any kind of sample preparation. They do, however, also have some limitations. Since the depth of focus is quite limited, especially at high magnifications, one will experience problems when trying to image strucutures that have been etched more than some 10 µm: One cannot focus on both the top and the bottom at the same time. Another disadvantage is the physical limit to the resolution that makes it impossible to image structures below 1 µm.
+Both shortcomings of the microscopes mentioned above are addressed if you use a SEM instead. The depth of focus and the resolution of a SEM are at least one order better.