3D metrology with a compact scanning probe microscope based on self-sensing cantilever probes

Abstract

The key element of a scanning force microscope (SFM) is the cantilever probe. Commonly, its deflection is measured using either an optical lever or interferometric methods. However, optical detection methods increase the complexity of the microscope set-up and restrict its application in difficult environments. By integrating the detection system on the cantilever chip itself, the microscope becomes easier to implement and use. Integrated systems have been realized based upon piezoelectric, piezoresistive and capacitive methods. In the present work self-sensing piezoresistive cantilevers have been used. For these probes a very compact SFM unit has been developed based upon a novel chip holder, which allows simultaneous fixing of the chip and contacting of the piezoresistive sensor electrodes. This compact unit can be tilted to perform investigations on three-dimensional structures not feasible with conventional scanning force microscopes. As an example of a 3D application, measurements on a 100 µm ruby sphere are presented.