Atomic force microscopy (AFM) is used for surface measurements with resolution down to atomic levels – dimensions that are far beyond even the highest resolution optical microscopes. AFM is a noncontact procedure, with forces between a very fine measuring tip and the object surface revealing information about the topography, chemical surface condition, defects, etc. Atomic force microscopy is an established method used both in research and in production with applications including materials research, nano/bio-technology life sciences, and semiconductor inspection. High spatial resolution requires extreme precision for positioning both the measuring tip and the sample. Piezo-flexure scanned nanopositioning stages are well suited for this scanning method because they provide sub-nm resolution along with fast response and high scanning rates.
While atomic force microscopy is not a novelty, a “low noise metrological AFM” designed at the PTB (German Institute of Standards and Technology) is taking it to the next level (Figure 1). This system will be employed for traceable measurements of step standards (used to calibrate other AFMs) and CD critical dimension (smallest reproducible structures) measurements in the latest semiconductor generation.