Multidimensional topography sensing simulating an AFM
| Autor: | Solomon Davis, Eyal Rubin, Izhak Bucher |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Materials science Acoustics Resolution (electron density) Metals and Alloys Resonance 02 engineering and technology 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials symbols.namesake Quality (physics) Experimental system Normal mode 0103 physical sciences symbols Curve fitting Electrical and Electronic Engineering van der Waals force 0210 nano-technology Instrumentation Frequency modulation |
| Zdroj: | Sensors and Actuators A: Physical. 303:111690 |
| ISSN: | 0924-4247 |
| DOI: | 10.1016/j.sna.2019.111690 |
| Popis: | Atomic force microscopy (AFM) is used in the semiconductor industry for inspection and quality control. Frequency modulated AFM (FM-AFM) extracts surface topography by measuring the frequency shift created by the Van der Waals (VdW) interaction forces between the tip and the sample. To improve the measurement speed and address complex geometries emerging in industrial microchip constructions, several enhancements are introduced. While most FM-AFM devices operate in a single vibrating mode, this article proposes a method for multidimensional sensing using frequency modulation of 2 orthogonal vibration modes, simultaneously. The concept was tested on a large-scale experimental system, where VdW forces were replaced by magnetic forces, using a magnetic tip and ferromagnetic samples. To emulate the VdW forces accurately, the designed ratio between the base frequency and frequency shift was kept to mimic a Nano-scale AFM. By utilizing an Autoresonance (AR) control scheme for faster locking onto resonance and a curve fitting frequency estimation algorithm it is possible to sense the minute changes in frequency experienced by several modes, simultaneously. Experimental results employ 3D relevant topographies such as inclined surfaces, steep walls and trenches that were reconstructed experimentally with 4 (μm) resolution or better. Downscaling to typical AFM dimensions would theoretically yield sub-nanometer resolution. |
| Databáze: | OpenAIRE |
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