It is relatively easy to make a cantilever with a spring constant low enough to sense the forces between atoms, such as a cantilever made of aluminium foil that is 4 mm long and 1 mm wide. However AFM cantilever manufacturers do not make cantilevers that large. They make them much smaller, typically 100 to 200 microns long and 20 to 50 microns wide. What is the reason for this

Scanning probe microscopy section Force Repulsion Forces Contact Distance D - Non Contact Attraction Forces