Pulsed plasmas have been proposed many years ago by research labs and have shown a great potential for etch process improvement. Nevertheless, they have been introduced in manufacturing only recently and the exact characteristics of pulsed plasmas in industrial scale reactors are hardly known. In this paper, we have characterized silicon etching in pulsed HBr/O₂ plasmas using advanced plasma diagnostics (mass spectrometry and ion flux probe) in a 300 mm industrial reactor. We show that pulsing the plasma at low duty cycle reduces the gas molecules dissociation and plasma temperature, as well as the flux of energetic ions to the wafer. The ions during silicon etching are mostly silicon-containing ions that are heavier at low duty cycle. Silicon patterns etched using pulsed plasmas present improved profiles, which is attributed to more uniform passivation layers at low duty cycle.

Date Published: 29 March 2013
PDF: 8 pages
Proc. SPIE 8685, Advanced Etch Technology for Nanopatterning II, 86850J (29 March 2013); doi: 10.1117/12.2011462

Published in SPIE Proceedings Vol. 8685:
Advanced Etch Technology for Nanopatterning II
Ying Zhang; Gottlieb S. Oehrlein; Qinghuang Lin, Editor(s)