Examination of several novel approaches for the measurement of two-dimensional roughness of sidewalls of high-aspect-ratio patterns using the atomic force microscope

Methods of measuring the surface roughness of the sidewalls of high aspect ratio patterns are presented. Cleaving the samples (developed resist and etched silicon) parallel to the long direction of the patterns and rotating the sample 90 degrees fully exposes the sidewall surfaces allowing investigation by either the Scanning Electron Microscope (SEM) or the Atomic Force Microscope (AFM). Another method, simply tipping over the lines in the developed resist samples also allows full access to the resist sidewall. While the SEM can be used to confirm the sidewall surface features, the AFM provides information such as the Root-Mean-Square (RMS) roughness, unobtainable through other methods.