On the chemistry mechanism for low-pressure chlorine process plasmas

Abstract

A chemical reaction mechanism of chlorine plasma under low-pressure conditions that is widely used in the literature is validated against the experimental data of Y. Wang and J. K. Olthoff [J. Appl. Phys. 85, 6358 (1999)] for an inductively coupled plasma reactor. The model used in the present study is a self-consistent two-dimensional fluid plasma model coupled with Maxwell’s equations. The quantities of interest in the plasma are the fluxes and energy distribution functions of Cl2+ and Cl+ ions. We find that the charge exchange reaction between Cl+ and Cl2 that is typically included in chlorine plasma reaction mechanisms results in poor predictability of the model compared to experiments. Neglecting this reaction allows for a correct prediction of the dominant ion species in the low-pressure chlorine plasma and dependence of their fluxes on the gas pressure. Additionally, neglecting the charge exchange reaction allows for a rather accurate prediction of ion energy distribution functions at the grounded electrode. Overall, we conclude that the rate coefficient of the charge exchange reaction between Cl+ and Cl2 reported in the literature significantly exceeds what may in fact explain the role of this process in a low-pressure plasma discharge.

Investigation of the dual-frequency bias effect on inductively coupled Cl2 plasmas by hybrid simulation

“…Furthermore, the EAE is mainly investigated in electropositive or weakly electronegative CCPs, such as Ar, H 2 , H 2 /SiH 4 and O 2 discharges [35,[41][42][43][44][45][46][47][48], and the studies in strongly electronegative gases, such as Cl 2 , are rarely reported. Actually, high-density Cl 2 plasmas have been widely used in the etching process as a preferable reactant with semiconductors, metals and composite ferroelectrics films [14,[49][50][51] Therefore, the purpose of this paper is to employ a hybrid model, i.e. a global model coupled bi-directionally with an ion Monte-Carlo collision (MCC) sheath model, to investigate the EAE on the separate control of the ion flux and ion energy in Cl 2 ICPs with DF bias sources.…”

Gas heating by inductively coupled low-pressure chlorine process plasmas

“…Based on the results of [10], Thorsteinsson and Gudmundsson [11] proposed convenient fitting formula which can be used for modeling of chlorine plasmas. Today, this fitting formula is used widely in both global and multidimensional plasma models to estimate the gas temperature [12,13].…”