Manufacturing of Tungsten Micro-tools by Electrochemical Etching: Study of the Electrical Parameters

Introduction: This paper aims to fabricate the high aspect ratio tungsten micro-tools with diameters up to 80µm by electrochemical etching. This process is simple and easy to develop, but it requires a deep study to achieve the fabrication of micro-tools with a diameter of 5 µm. Methods: In this work, we studied the effect of the pulsed signal parameters used during the electrochemical etching. The parameters studied are VON and TOFF (The applied voltage and the rest phase, respectively). Results: The experiments show that VON = 0.5V leads to satisfactory results (validation of the reproducibility, homogeneous etching, and fabrication of micro-tools with a diameter of 80µm with an initial tungsten wire diameter of 250µm) by applying an etching charge of 13 C. Voltages VON = 0.1V and VON = 1V does not ensure homogeneous etching. A rest phase TOFF = 3s allows obtaining microtools with a diameter of 80µm in 7 min. For a rest phase of TOFF = 9s, the etching takes 20 min and the micro-tool diameter is almost the same. Conclusion: The results of this study will be used in the manufacture of cylindrical micro-tools with a high aspect ratio Fc > 100.