Novel hybrid interference and atomic force microscopy

A novel hybrid microscope which combines an interference microscopic (IM) and an atomic force microscopic (AFM) measurement mode is introduced. It is realised by adding an AFM probe to an IM, where the AFM probe can be mechanically switched in or out of the beam path of the IM. When the AFM cantilever is out of the beam path, the system works in the IM measurement mode for noncontact and fast optical measurements. When the AFM cantilever is in the beam path, it works in the AFM measurement mode, where the AFM tip interacts with sample surfaces for measurements. The deformation of the AFM cantilever induced by the tip-sample interaction force is detected from interference fringes, which are formed by the interference of the light beam reflected from the backside of the AFM cantilever and a reference beam in the IM. This novel design has a high-level synergy of AFM and IM technologies and provides promising application potentials. For instance, the limited resolution capacity of the IM mode can be complemented by the high-resolution AFM. AFM measurements are capable of offering measurement results with higher topography fidelity than IM measurements, thus for providing in-situ reference areal surface metrology. In the paper, design concept, realisation of a prototype instrument, and experimental results illustrating the performance of the prototype instrument are detailed.