Fabrication of Atomic Force Microscope Probe with Low Spring Constant Using SU-8 Photoresist

Microfabrication processes of atomic force microscope (AFM) probe using SU-8 photoresist have been developed. Photolithographic patterning of the SU-8 on the anisotropically etched Si substrate produced the AFM cantilever with integrated tip. Use of the self-assembled monolayers and Al interlayer between the SU-8 and the Si substrate played a significant role for retrieving the probe out of the Si micromold without any damage. Fabricated SU-8 probe with a relatively sharp tip (radius of curvature ∼80 nm) had a resonant frequency of 44 kHz, which yields a spring constant of 0.248 N/m.