Atomic force profilometry and long scan atomic force microscopy: New techniques for characterisation of surfaces

Abstract

Existing methods of characterising surface topography (planarity, feature dimensions, roughness, etc.) include atomic force microscopy (AFM) and stylus profilometry. Stylus profilers can scan up to 200 mm in length to characterise global planarity, but are limited in their lateral resolution for accurately characterising micro- and submicrometre features. They can also cause damage to the surface under study by dragging the stylus with forces in excess of what the surface can tolerate without inelastic deformation occurring. The AFM is gentler on the specimen than stylus profilers and has higher lateral resolution, but is limited in its ability to image areas greater than 100 × 100 μm. Two new types of metrology tools, the atomic force profiler and the long scan AFM, have been developed, combining AFM resolution, non-destructive characterisation capability, and long profile lengths. These tools can be used for measuring surface roughness, waviness, profile, step height, and angle, as well as for imaging surface defects. The main characteristics of these tools are presented, in addition to respective measurement data from each.