DIMENSIONAL METROLOGY WITH SCANNING PROBE MICROSCOPES

We review the application of scanning probe microscopes to dimensional measurement of topographic features. Probe microscopes show great pro mise as metrology tools because they produce three-dimensional data ov er almost all solids in a wide range of ambients. Even though these mi croscopes readily achieve atomic resolution, there are several aspects of their behavior that can cause them to exhibit large measurement er rors. 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 intera ction intrinsically nonlinear. Forces on the probe that cause it to fl ex are another source of inaccuracy. Probe fabrication and characteriz ation are, consequently, important issues. We describe present underst anding of these problems and the techniques being developed to solve t hem.