Elucidating the effects of gas flow rate on an SF6 inductively coupled plasma and on the silicon etch rate, by a combined experimental and theoretical investigation

Stefan Tinck (1) , Thomas Tillocher (2) , Remi Dussart (2) , Erik Neyts (1) , Annemie Bogaerts (1)

1 Research group PLASMANT
2 GREMI - Groupe de recherches sur l'énergétique des milieux ionisés

Experiments show that the etch rate of Si with SF6 inductively coupled plasma (ICP) is significantly influenced by the absolute gas flow rate in the range of 50–600 sccm, with a maximum at around 200 sccm. Therefore, we numerically investigate the effects of the gas flow rate on the bulk plasma properties and on the etch rate, to obtain more insight in the underlying reasons of this effect. A hybrid Monte Carlo—fluid model is applied to simulate an SF6 ICP. It is found that the etch rate is influenced by two simultaneous effects: (i) the residence time of the gas and (ii) the temperature profile of the plasma in the ICP volume, resulting indeed in a maximum etch rate at 200 sccm.

Domaines: Physique des plasmas [physics.plasm-ph]

Stefan Tinck, Thomas Tillocher, Remi Dussart, Erik Neyts, Annemie Bogaerts. Elucidating the effects of gas flow rate on an SF6 inductively coupled plasma and on the silicon etch rate, by a combined experimental and theoretical investigation. Journal of Physics D: Applied Physics, 2016, 49 (38), pp.385201. ⟨10.1088/0022-3727/49/38/385201⟩. ⟨hal-01374746⟩