| AVS 65th International Symposium & Exhibition | |
| Plasma Science and Technology Division | Monday Sessions |
| Session PS+AS+EM+SS-MoM |
| Session: | Plasma-Surface Interactions |
| Presenter: | Yusuke Fukunaga, Nagoya University, Japan |
| Authors: | Y. Fukunaga, Nagoya University, Japan P.L.G. Ventzek, Tokyo Electron America, Inc. B. Lane, Tokyo Electron America, Inc. A. Ranjan, TEL Technology Center America, LLC M. Sekine, Plasma Nanotechnology Research Center, Japan T. Tsutsumi, Plasma Nanotechnology Research Center, Japan H. Kondo, Plasma Nanotechnology Research Center, Japan K. Ishikawa, Plasma Nanotechnology Research Center, Japan R. Upadhyay, Esgee Technologies L. L. Raja, The University of Texas at Austin G. Hartmann, McKetta Department of Chemical Engineering, The University of Texas at Austin G. S. Hwang, The University of Texas at Austin M. Hori, Institute of innovation for future society, Japan |
| Correspondent: | Click to Email |
Organic film etching is important for semiconductor device fabrication especially as it relates to self-aligned-multiple-patterning in which sub-nanometer scale pattern replication is critical. Even though the etching of organic materials has been studied for decades (e.g., O2 plasma ashing), new process applications (e.g. ALE) and new chemistry regimes render older models of organic etching such as those employing the Ohnishi parameter of limited use.[1] Existing kinetic models rely on untested assumptions such as the role of dangling bonds as reaction initiating sites.[2] A need exists to revisit the fundamentals of plasma surface interactions as they pertain to the etching of organic films. Moreover, a need exists to incorporate fundamental kinetic models with macroscale models which could be used for process development.
Progress has been slow because of the computational weight of modeling the chemical kinetics and difficulty defining a tractable problem. In this presentation, we describe the use of an integrated modeling framework involving fundamentals-based ab-initio and plasma chemistry simulations with high performance computing to describe chemical kinetics on model polymer systems. In O2 and Ar plasmas, we use finite carbon size strands with varying degrees of O, OH or H termination as model structures. For simplicity, the structures are polyethylene-like. We use density functional theory (DFT) to model the interactions between plasma species and representative structures. To estimate the relative importance of plasma species and their energy, we derive species and energy flux from a macroscale plasma chemistry model. Both DFT and ab-initio molecular dynamics (AIMD) simulations are used to probe the chemical stability of representative structures to different plasma species (e.g., Ar, O) and energy fluxes. We found that O addition to H terminated structures results in OH group formation on polyethylene by exothermic reaction. Ar ion bombardment formed carbon strands may also be oxidized. The resultant structures (oxo-carbon) are also stable up to large oxygen to carbon ratios. The stability to Ar ion bombardment will be presented. An essential test of any new mechanism is experimental validation. In addition to the computational results, we will present experimental results ranging from basic etch rate measurements to measurements of plasma processed material chemical composition (e.g., XPS).[3]
References:
[1] H. Gokan, et al., J. Electrochem. Soc.: Solid-state Sci. Technol. 130, No. 1, 143 (1983).
[2] F. D. Egitto, Pure & Appl. Chem. 62, No. 9, 1699 (1990).
[3] D. U. B. Aussems, et al., Chem. Sci. 8, 7160 (2017).