AVS 66th International Symposium & Exhibition
    Plasma Science and Technology Division Tuesday Sessions
       Session PS+EM-TuA

Paper PS+EM-TuA4
Non-selective Silicon Oxide and Nitride Etch in Oxygen/Nitrogen-containing Fluorocarbon Plasmas

Tuesday, October 22, 2019, 3:20 pm, Room B131

Session: Advanced BEOL/Interconnect Etching and Advanced Memory and Patterning
Presenter: Yu-Hao Tsai, TEL Technology Center, America, LLC
Authors: Y.-H. Tsai, TEL Technology Center, America, LLC
D. Zhang, TEL Technology Center, America, LLC
Y. Han, TEL Technology Center, America, LLC
J. Baillargeon, TEL Technology Center, America, LLC
Y. Shi, TEL Technology Center, America, LLC
H. Kim, TEL Technology Center, America, LLC
M. Wang, TEL Technology Center, America, LLC
T. Yokoyama, Tokyo Electron Miyagi Ltd., Japan
M. Iwata, Tokyo Electron Miyagi Ltd., Japan
Y. Kihara, Tokyo Electron Miyagi Ltd., Japan
M. Honda, Tokyo Electron Miyagi Ltd., Japan
W. Sakamoto, Tokyo Electron Miyagi Ltd., Japan
A. Mosden, TEL Technology Center, America, LLC
A. Metz, TEL Technology Center, America, LLC
P.E. Biolsi, TEL Technology Center, America, LLC
Correspondent: Click to Email
Performing an all-in-one etch process for 3D-NAND fabrication requires comparable and high etch rates (E/R) for SiO2 and Si3N4; the goal remains challenging. As the discrepancy of E/R largely results from the different nature of materials, surface modifications of SiO2 and Si3N4 to achieve comparable composition during etch can improve the desired non-selectivity. In the presented work, we study the conversion of SiO2 [Submitted] and Si3N4 [J. Micro. Manuf.1, 20180102 (2018)] to oxynitride (SiOxNy) via the nitridation and oxidation-etch reactions, respectively. We computationally identify the etching mechanism of SiO2/Si3N4 in the N/O-containing fluorocarbon plasmas using both quantum chemistry (QC) and molecule dynamics (MD) simulations; the surface conversion to SiOxNy is predicted. The results are further validated by the plasma etching of blanket SiO2 and Si3N4 films in a Capacitively Coupled Plasma (CCP) chamber; both E/R trends and surface analysis on validation of oxinitride and/or nitrioxide (SiOxNy) formation using methods such as XPS, EDS etc. are discussed. We detail the etch reaction pathway, in which the elimination of O/N atom forming nitric oxide (NO) species is predicted. Along with that, the synergy of having F species in the process is justified. Finally, we discuss the impact of fluorocarbon to N/O ratio on the preference of either high E/R or active SiOxNy formation. The research builds a foundation for future development work on pursuing robust all-in-one non-selective SiO2/Si3N4 etch processes.