High‐Precision Silicon Microgrooves via Metal‐Assisted Chemical Etching (MACE) Using Electrospun Nanofibers

ABSTRACT Silicon nano/microstructures have attracted significant interest for their applications in electronics, sensors, and energy devices. However, conventional photolithography‐based fabrication processes face challenges such as high cost, procedural complexity, and limited scalability for large‐area patterning. In this study, we propose a novel and cost‐effective fabrication method to precisely create silicon nano/microstructures by utilizing metal mask patterning based on electrospinning. The palladium (Pd) nanocluster patterns, with linewidths below 1 µm formed by electrospinning, act either as catalysts or protective masks depending on the etching environment. Under acidic conditions, Pd acts as a catalyst for metal‐assisted chemical etching (MACE), forming semicircular silicon structures along the nanofiber patterns. In alkaline environments, the porous nature of the Pd clusters allow partial penetration of the etchant, enabling anisotropic etching and lift‐off effects that produce pyramid‐shaped microgrooves with crystallographic angles of 54.74°. This process achieves structures with 5–10 µm linewidths and feature spacing as narrow as 1 µm. Conducted under atmospheric pressure and without the need for expensive equipment, this technique presents strong potential for next‐generation microelectronic and biosensing applications.