AVS 53rd International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS2-MoM

Paper PS2-MoM5
Plasma Atomic Layer Etching Using Conventional Plasma Equipment*

Monday, November 13, 2006, 9:20 am, Room 2011

Session: Advanced Gate Fabrication
Presenter: A. Agarwal, University of Illinois at Urbana-Champaign
Authors: A. Agarwal, University of Illinois at Urbana-Champaign
M.J. Kushner, Iowa State University
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The thinning of the dielectric in gate stacks and the need to resolve etching on an atomic layer basis in applications such as FinFETs present large technological challenges in plasma etching. To insure atomic-level control it is desirable to use a self-limiting process which is independent of the processing time. In plasma atomic layer etching (PALE), formation of a monolayer of reactants or passivation is followed by the removal of the layer that then self terminates the process. For example, deposition of a thin layer of polymer or passivation in a non-etching plasma followed by etching in a non-polymerizing plasma with low energy ion energy could remove only a single layer or less of underlying material. The higher threshold energy required to remove the underlying material in the absence of the passivation would self-terminate the process. A challenge is to perform these processes in conventional plasma equipment as opposed to highly specialized beam equipment. In this talk, results from a computational investigation of PALE will be discussed with the goal of demonstrating the potential of the process using conventional etching tools. The Hybrid Plasma Equipment Model (HPEM) and the Monte Carlo Feature Profile Model (MCFPM) were modified to have pulse periodic capability as required for PALE, and to kinetically resolve ion energy distributions to finely resolve threshold energies. Results for PALE will be discussed, for geometries of interest to future technological nodes, for at least two systems: 1) PALE of Si using steps of an Ar/Cl@sub 2@ plasma (passivation) followed by Ar plasma (etch) and 2) PALE of SiO@sub 2@ using steps of a fluorocarbon plasma (passivation) followed by an Ar plasma (etch). @FootnoteText@ *Work supported by Semiconductor Research Corp. and the National Science Foundation.