A double ignition strategy for enhanced efficiency in atmospheric plasma machining

Abstract

Due to the advantages of high efficiency, low cost and versatile operation, atmospheric plasma machining has drawn significant attention in the field of semiconductor and optical fabrication. Nevertheless, for conventional atmospheric plasma machining sources feature low temperature, the machining efficiency is limited due to the low gas ionization rate. This paper presents a novel double ignition strategy based on coupled coupling plasma (CCP) for enhanced radical concentration and machining efficiency. The double ignition plasma jet (DIPJ) enhances electron concentration and promotes the dissociation of fluorine radicals compared to single ignition plasma jet (SIPJ), exhibiting higher removal efficiency. Afterwards, the jet characteristics are significantly affected by regulating the electric field distribution of DIPJ through adjusting the structural parameters, which further promotes the ignition strength and radical generation. With the optimization of ignition configuration and process parameters, a Gaussian removal function can be obtained and the material removal rate (MRR) can be reached over 0.4 mm³/min at a full width at half maximum (FWHM) of 4.8 mm. The form error of a 100 × 50 mm² Si planar mirror can be reduced from 150.41 nm to 19.36 nm RMS within 7.9 min after one iteration of figuring, which demonstrates the high processing efficiency optical manufacturing.