Work

Optimization Method for the Synergistic Control of DRIE Process Parameters on Sidewall Steepness and Aspect Ratio

Year: 2025

Type: article

Abstract: Deep Reactive Ion Etching (DRIE), as a key process in silicon micromachining, remains constrained in high-precision applications by sidewall angle deviation and aspect ratio limitations. This study systematically investigates the mapping relationship between process parameters and etching morphology, focusing on: The influence mechanism of C₄F₈ passivation time and bottom RF power on sidewall perpendicularity The effect patterns of etch cycle count, single-step time, and bottom RF power on aspect ratio and top-bottom line width (CD) difference Findings reveal: Dynamic adjustment of bottom RF power significantly influences sidewall angle. Incremental adjustment tends to cause sharp angles (decreased angular precision), while decremental adjustment tends to form obtuse angles. Simply increasing cycle count leads to a bottleneck in etch depth growth. Combining incremental bottom RF power adjustment can overcome depth limitations but induces axial variation in aperture dimensions. Optimizing the pas-sivation-etch time ratio effectively controls etch morphology characteristics. This study achieved an etch depth of 112.2 μm for a 5 μm wide trench with an overall ap-erture size difference of 0.279 μm, providing a theoretical basis and practical guidance for parameter optimization in DRIE processes for high-precision silicon structure fab-rication.

Source: Micromachines

DOI: 10.3390/mi17010013