The design of an atomic force microscope (AFM) starts from the observation when the tip of such a microscope probe a surface, the working distances (of the order of angström) are such that significant forces are exerted between the atoms of the tip and those of the surface.
A device capable of amplifying the local variations of these forces during scanning should allow force mapping at the atomic scale, revealing the surface topography. The simplest amplifier device is a lever with a solid tip. It is on these simple considerations that the idea of the atomic force microscope was born: to make a profilometer with very high resolution. The success that followed was immediate.
The advantages are enormous since one can analyze any type of material, and most often by air (there are now microscopes operating in ultravacuum, if the study requires it). Force maps can be obtained at the atomic scale if the condition of the surface allows (rough surfaces). The analysis windows range from the nanometer fraction to tens of micrometers, allowing for mesoscopic-scale vision of a surface.
The AFM also has difficulties in precise positioning of the probe on the measuring surface and the need for use by a qualified person (correct mounting of the cantilever, etc.)