A reproducible electropolishing technique to customize tungsten SPM probe: From mathematical modeling to realization

The present work is carried out with the aim of developing an optimized electropolishing technique for the process of electrochemical etching from mathematical modeling to the final realization of the well-prepared tungsten SPM probes. Based on the axisymmetric shapes of bounded interfaces, a calculation scheme of successive approximation is derived, which facilitates the numerical solutions for a wide range of parameter values which will cover most practical situations. The proposed art of electrochemical etching technique and process are experimentally confirmed to have advantages for the tungsten probe fabrication of the stabilized stylus contour, ultra-sharp apex radius and high production reproducibility. The tungsten probes with profiles of exponential, conical, and multi-diameter with stabilized stylus contour, and ultra-sharp apex radius are fabricated. The characteristic parameters of the probe including length, aspect ratio and tip apex radius can also be well defined. The reproducible technique opens a way of batch customization of metallic SPM probes with high quality.