DIMENSIONAL METROLOGY WITH SCANNING PROBE MICROSCOPES

We review the application of scanning probe microscopes to dimensional measurement of topographic features. Probe microscopes show great promise as metrology tools because they produce three-dimensional data over almost all solids in a wide range of ambients. Even though these microscopes readily achieve atomic resolution, there are several aspects of their behavior that can cause them to exhibit large measurement errors. The actuators that drive the probe exhibit hysteresis and creep, so they must be independently monitored. In addition, the geometry of an extended probe moving across the surface makes probe-sample interaction intrinsically nonlinear. Forces on the probe that cause it to flex are another source of inaccuracy. Probe fabrication and characterization are, consequently, important issues. We describe present understanding of these problems and the techniques being developed to solve them.