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

Existing methods of characterising surface topography (planarity, feature d imensions, roughness, etc.) include atomic force microscopy (AFM) and stylu s profilometry. Stylus profilers can scan up to 200 mm in length to charact erise global planarity, but are limited in their lateral resolution for acc urately characterising micro-and submicrometre features. They can also caus e damage to the surface under study by dragging the stylus with forces in e xcess of what the surface can tolerate without inelastic deformation occurr ing. The AFM is gentler on the specimen than stylus profilers and has highe r lateral resolution, but is limited in its ability to image areas greater than 100 x 100 mu m. Two new types of metrology tools, the atomic force pro filer and the long scan AFM, have been developed, combining AFM resolution, non-destructive characterisation capability, and long profile lengths. The se tools can be used for measuring surface roughness, waviness, profile, st ep height, and angle, as well as for imaging surface defects. The main char acteristics of these tools are presented, in addition to respective measure ment data from each.