Specific Process Knowledge/Characterization/Topographic measurement: Difference between revisions

The fact that the tips of the Dektak profilers and the AFM are shaped like a cone with some tip angle causes a problem when characterizing high aspect ratio structures. For instance, if a 20 <math>\mu</math>m wide trench is etched deeper than approximately 18 <math>\mu</math>m, the tip of the Dektak will not be able to reach the bottom. The optical profiler uses a light beam that are focused through an objective therefore it is able to measure higher aspect ratios. The aspect ratio is limited by the posibility for the light to reach the bottom and get back to the detector. On some samples we have been able to measure aspect ratios above 1:10. Other wise the solution is to cleave the sample along a line that is perpendicular to the trench and then put it in a [[Specific Process Knowledge/Characterization/SEM: Scanning Electron Microscopy|scanning electron microscope]].