Understanding atomic force microscopy
A comprehensive guide to AFM fundamentals, nano analytik's active cantilever technology, and how our approach compares to classical AFM systems.
Why Active Cantilevers Matter ?
Classical AFM systems use optical beam deflection (OBD) to detect cantilever motion. While OBD is a proven and sensitive technique, it comes with inherent limitations in terms of complexity, alignment, and applicability. The challenge in realizing next-generation atomic force microscopes is maintaining atomic resolution while scanning at speeds needed for high-throughput imaging and metrology. This requires precise, fast detection of tip–sample interactions. For that the cantilevers must be small and soft with high signal-to-noise ratios. Conventional optical read-out works against this: diffraction limits sensitivity, the external components make the system bulky and expensive, and a minimum reflective area of approximately 3 µm is required on the cantilever backside even in high-end systems for facilitating a small laser spot. As probe dimensions scale down, this optical footprint becomes the bottleneck. By integrating sensing and actuation directly onto the probe, nano analytik's active cantilever approach directly addresses each of these limitations. The active cantilever AFM design is robust to environment and less optics-dependent; the absence of external laser or light paths reduces sensitivity to vibrations, ambient light, and scattering, which is beneficial in dusty or illuminated industrial environments. For AFM users, this translates into no optical alignment effort, a substantially lower component count, simplified assembly, reduced maintenance, lower cost of ownership, and a more compact system architecture. Compared with OBD-based architectures, active-cantilever AFM can offer a more compact and integration-friendly route to high-resolution measurement, while the best choice still depends on the application, measurement mode, and system requirement.
Plug-and-Image
Integrated electrical sensing eliminates the need for laser alignment and detector positioning during probe replacement. Swapping a cantilever is as simple as plugging in a new chip, enabling rapid probe exchange and faster switching between different measurement modes and probe types.
Seamless System Integration
Active cantilevers integrate directly into environments conventional AFM cannot reach. Their compact architecture enables straightforward integration into vacuum chambers and SEM platforms, where routing a laser to the cantilever backside is impractical. They can be combined with optical inspection techniques such as phase-shift interferometry, enabling nanoscale topographic measurements alongside high-speed full-field optical characterization. The elimination of external optical components produces a significantly smaller, lighter instrument, one that is easier to control, simpler to automate, and well-suited to the precision demands of metrological and lithographic workflows.
High-Throughput Parallel Imaging
Scaling AFM to multiple probes operating in parallel is fundamentally incompatible with optical beam deflection - each cantilever would require its own dedicated laser and detector. Electrical read-out removes this constraint entirely, making cantilever arrays and parallel probe architectures a practical reality. nano analytik GmbH has demonstrated parallel active cantilever arrays as a practical tool for high-throughput inspection and metrology, This opens a path toward wafer-scale nanoscale imaging at throughputs required by the semiconductor industry.