Stiffness mapping, scanning force

The tip is thus engaged similar to contact mode AFM. Scan rates of 1 Hz and low imaging forces are advisable to minimize possible impact of lateral forces. During each scan line the tip periodically indents the sample surface. From the feedback loop correction for the z-component for each pixel a topography (height) image is obtained the simultaneously recorded rms cantilever amplitude provides a stiffness map [117]. 

In general, the available indentation techniques are based either on scanning force microscopy (SFM) or on dedicated indentation setups providing well-defined tip geometries. The two approaches are described in Sections 8.2.1 and 8.2.2, respectively. Issues related to potential artifacts in IP characterization are discussed in Section 8.3. Finally, examples of epoxy IP characterization by means of SFM-based stiffness mapping as well as depth-sensing micro-indentation (DSI) are given in Sections 8.4.1 and 8.4.2, respectively. 

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