| abstract |
A probe tip of a scanning probe microscope or a profilometer is scanned across a surface in a contact, non-contact, or intermittent contact mode to sense the presence of a feature to be located. The probe tip may be scanned along substantially parallel paths, spiral paths or in a sequence of random positions to locate the feature. After the feature has been located, a different searching sequence is employed in order to locate a center of the feature if such is desired. Then, the probe tip is scanned across the surface over the center of the feature in order to perform a measurement of the feature. For some particular features such as tungsten plugs, metal clusters or metal filled via holes of a surface, an electrical or magnetic parameter of the feature may be used for locating the feature after which the same or a different characteristic of the feature, such as geometric profile, can be measured. |