Abstract : In this work, we optimize a CH$_3$F/O$_2$/He/SiCl$_4$ chemistry to etch silicon nitride gate spacers for 3D CMOS devices in a 300mm inductively
coupled plasma reactor. The chemistry has high directivity and high selectivity to Si and SiO$_2$. A cyclic approach, which alternates this
chemistry with a CH$_2$F$_2$/O$_2$/CH$_4$/He plasma, is investigated. Using $quasi\ in\ situ$ x-ray photoelectron spectroscopy and ellipsometry measurements,
etching mechanisms are proposed to explain the results obtained. As a result of process optimization, silicon nitride spacers with vertical
profile and a small critical dimension loss of 3 nm as well as complete spacers removal on sidewalls of the active area are obtained on
3D patterns, confirming the advantages of this approach.
https://hal-cea.archives-ouvertes.fr/cea-03343549 Contributor : Contributeur MAP CEAConnect in order to contact the contributor Submitted on : Tuesday, September 14, 2021 - 11:30:02 AM Last modification on : Thursday, September 16, 2021 - 3:23:58 AM Long-term archiving on: : Wednesday, December 15, 2021 - 6:22:38 PM
Valentin Bacquie, Aurelien Tavernier, Francois Boulard, Olivier Pollet, Nicolas Posseme. Gate spacers etching of Si$_3$N$_4$ using cyclic approach for 3D CMOS devices. Journal of Vacuum Science and Technology A, American Vacuum Society, 2021, 39, pp.033005. ⟨10.1116/6.0000871⟩. ⟨cea-03343549⟩