Mechanism of pressure on the etching precision of polymer nanostructured surfaces

Polymer nanostructures have been found extensive applications in fields such as integrated circuits and intelligent sensing. However, existing reactive ion etching technologies still face challenges in achieving high precision and uniformity control. This paper systematically investigates the critical role of chamber pressure in O 2 /Ar reactive ion etching, revealing its profound influence on the morphology, etching rate, and uniformity of spherical-curved nanostructures. Experimental results demonstrate that chamber pressure is a critical parameter for modulating etching behavior: at 1-3Pa, etching proceeds slowly but results in rough structures, making it suitable for constructing hierarchical micro/nanostructures; the 4-6Pa range offers optimal etching uniformity, enabling highprecision morphological control; while pressures >7Pa dramatically accelerate the etching rate, facilitating efficient material removal. Through macroscopic plasma fluid simulations, ion transport kinetics diagnostics, and X-ray photoelectron spectroscopy (XPS) analyses, it is revealed that chamber pressure acts as a critical dial to modulate the competitive synergy between physical sputtering and chemical oxidation. The comprehensive diagnostics successfully unveil the underlying physics driving the morphological transition from rough anisotropic "flying-saucers" to smooth isotropic nanospheres. This study provides a novel method and theoretical foundation for high-precision, controlled etching of polymer nanostructures, holding significant implications for the further advancement of the nanoscale precision etching process.