Dry Etching Performance and Gas-Phase Parameters of C6F12O + Ar Plasma in Comparison with CF4 + Ar

Nomin Lim,Yeon Sik Choi,Alexander Efremov,Kwang-Ho Kwon

doi:10.3390/ma14071595

Nomin Lim, Yeon Sik Choi + Show 2 more

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https://doi.org/10.3390/ma14071595

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Abstract

This research work deals with the comparative study of C6F12O + Ar and CF4 + Ar gas chemistries in respect to Si and SiO2 reactive-ion etching processes in a low power regime. Despite uncertain applicability of C6F12O as the fluorine-containing etchant gas, it is interesting because of the liquid (at room temperature) nature and weaker environmental impact (lower global warming potential). The combination of several experimental techniques (double Langmuir probe, optical emission spectroscopy, X-ray photoelectron spectroscopy) allowed one (a) to compare performances of given gas systems in respect to the reactive-ion etching of Si and SiO2; and (b) to associate the features of corresponding etching kinetics with those for gas-phase plasma parameters. It was found that both gas systems exhibit (a) similar changes in ion energy flux and F atom flux with variations on input RF power and gas pressure; (b) quite close polymerization abilities; and (c) identical behaviors of Si and SiO2 etching rates, as determined by the neutral-flux-limited regime of ion-assisted chemical reaction. Principal features of C6F12O + Ar plasma are only lower absolute etching rates (mainly due to the lower density and flux of F atoms) as well as some limitations in SiO2/Si etching selectivity.

Highlights

Silicon-based electronics still play the leading role in the worldwide production of integrated electronic circuits
This work reports on the comparative study of C6 F12 O + Ar and CF4 + Ar gas chemistries in respect to Si and SiO2 reactive-ion etching processes under the condition of low input power mode
The X-ray photoelectron spectroscopy showed no principal differences in corresponding polymerization abilities

Summary

Introduction

Silicon-based electronics still play the leading role in the worldwide production of integrated electronic circuits. The main feature of RIE is the simultaneous action of two parallel etching mechanisms, such as physical sputtering and ion-assisted chemical reaction [5,6]. This provides the effective adjustment of output process characteristics (etching rate, etching profile, selectivity in respect to mask and/or under-layer material, etching residues, surface roughness, etc.) by an appropriate choice of working gas and processing conditions [2,3,4,5]

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