A Novel HBR-Based High Selectivity Non-Bosch Deep Silicon Etching Process Enhancing Mechanical Performance for MEMS Device

This paper reports a novel HBr-based, high-selectivity, non-Bosch deep silicon etching process capable of producing smooth etched surfaces while maintaining comparable selectivity and verticality to the conventional Bosch process. By eliminating the scallop structures inherent to the Bosch method, this non-Bosch approach significantly enhances the mechanical strength of silicon structures. Comparative analysis with varying HBr proportions confirms that this method increases the torsional fracture strength of silicon structures by approximately 38% compared to the Bosch process. This advancement holds broad applicability in the fabrication of various MEMS devices, offering a promising pathway to improve their mechanical strength and overall reliability.