3D modeling of feature-scale fluorocarbon plasma etching in silica

• Published in: Journal of computational electronics Vol. 22; no. 5; pp. 1558 - 1563
• Main Authors: Rodrigues, Frâncio, Felipe Aguinsky, Luiz, Lenz, Christoph, Hössinger, Andreas, Weinbub, Josef
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-10-2023; Springer Nature B.V
• Subjects: Adsorption; Approximation; Boundary conditions; CMOS; Dynamic random access memory; Electrical Engineering; Engineering; Etchants; Mathematical and Computational Engineering; Mathematical and Computational Physics; Mechanical Engineering; Memory devices; Methodology; Modelling; Optical and Electronic Materials; Perfluorocarbons; Plasma etching; Polymers; Random access memory; Reaction mechanisms; Silicon dioxide; Surface reactions; Theoretical; Three dimensional models; Topography; Level-set; Process modeling; Feature-scale; Langmuir kinetics; TCAD
• ISSN: 1569-8025; 1572-8137
• DOI: 10.1007/s10825-023-02068-y

Fluorocarbon dry etching of vertical silica-based structures is essential to the fabrication of advanced complementary metal-oxide-semiconductor and dynamic random access memory devices. However, the development of etching technology is challenged by the lack of understanding of complex surface reaction mechanisms and by the intricacy of etchant flux distribution on the feature-scale. To study these effects, we present a three-dimensional, TCAD-compatible, feature-scale modeling methodology. The methodology combines a level-set topography engine, Langmuir kinetics surface reaction modeling, and a combination of reactant flux evaluation schemes. We calibrate and evaluate our model to a novel, highly selective, etching process of a
SiO
2
via and a
Ru
hardmask by
CF
4
/
C
4
F
8
. We adapt our surface reaction model to the novel stack of materials, and we are able to accurately reproduce the etch rates, topography, and critical dimensions of the reported experiments. Our methodology is therefore able to prototype and study novel etching processes and can be integrated into process-aware three-dimensional device simulation workflows.