Tip current/positioning close-loop mode of scanning electrochemical microscopy for electrochemical micromachining

•A tip current/positioning close-loop mode is designed for scanning electrochemical microscopy.•The motion trail of SECM tip can be pre-programmed by this positioning mode.•The SECM mode is verified powerful to fabricate arbitrary 3D microstructures.

Scanning electrochemical microscopy (SECM) has been approved as a prospective electrochemical micromachining (ECMM) technique soon after its birth. However, it still remains challenge for SECM to fabricate arbitrary three-dimensional (3D) microstructures because of the limitation of positioning system. To solve this problem, we proposed a tip current signal/positioning close-loop mode in which the tip current signal is fed back to the positioning system in order to program the motion trial of SECM tip. Both the triedge-cone and sinusoidal microstructures were obtained by the close-loop positioning mode. The static-state etching process was demonstrated not to be disturbed by the slow motion rate of SECM tip. The unique positioning mode would be significant for both ECMM and electrochemical imaging.