Title: Silicon nitride hardmask fabrication using a cyclic CHF3-based reactive ion etching process for vertical profile nanostructures
Authors: Kaspar, Peter ×
Jeyaram, Yogesh Sharma
Jaeckel, Heinz
Foelske, Annette
Koetz, Ruediger
Bellini, Sandro #
Issue Date: Nov-2010
Publisher: Published for the Society by the American Institute of Physics
Series Title: Journal of Vacuum Science & Technology B, Microelectronics and Nanometer Structures vol:28 issue:6 pages:1179-1186
Abstract: A cyclic approach to silicon nitride dry-etching is presented, which differs in concept from most established high aspect ratio etching processes. Alternating steps of CHF3 etching and oxygen plasma treatment are applied to form vertical sidewalls. During the CHF3 etching step, an etch-inhibiting fluorocarbon film gradually forms on silicon nitride surfaces, whereas the oxygen plasma step removes the fluorocarbon layer and restores the bare nitride surface. By adjusting the timing between the two steps, the etch-inhibition by the fluorocarbon film can be controlled to yield vertical sidewalls. Using x-ray photoelectron spectroscopy, the formation and removal of the fluorocarbon film are confirmed, and its chemical composition is analyzed. The authors show the influence of cycle step duration on etched sidewall angles and present the results of an optimized set of etching parameters for smooth and vertical sidewalls. By feeding only one gas at a time to the plasma reactor, they avoid having to control the delicate balance between the fluxes of species that deposit and etch the fluorocarbon film. This makes their process very robust and removes the highly variable effects of reactor wall conditions. Finally, the authors comment on the feasibility of implementing a process for etching silicon dioxide in a similar fashion. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3501120]
ISSN: 1071-1023
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Non-KU Leuven Association publications
× corresponding author
# (joint) last author

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