Measurements of thickness of a thin film, while being deposited or after being deposited, and of surface undulation are required in many applications. A number of techniques to cover a large range of thickness have been developed. These techniques are based on triangulation principle, interference, polarization, and so on. Some of these techniques are described in this chapter.
10.1 TRIANGULATION-BASED PROBE
This makes use of laser radiation as it can be focused to a tight spot on the surface of an object that is diffuse. A well-corrected lens images the spot on a linear array detector, which is aligned perpendicular to the optical axis of the imaging lens. Figure 10.1 shows the schematic of the instrument.
If the ...
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