AVS 50th International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS-TuA

Paper PS-TuA4
Investigation of Bottom-emitted Particles and their Influence on the Etch Characteristics of Sidewall in the Fluorocarbon Plasma Etching

Tuesday, November 4, 2003, 3:00 pm, Room 315

Session: Dielectric Etch
Presenter: G.-R. Lee, Seoul National University, Korea
Authors: G.-R. Lee, Seoul National University, Korea
J.-H. Min, Seoul National University, Korea
J.-K. Lee, Seoul National University, Korea
S.H. Moon, Seoul National University, Korea
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When energetic ions impinge on the bottom of an etched pattern, various particles are emitted from the bottom surface, which constitute an additional source for modifying the composition of plasma gases besides collisions among gas-phase particles generated in a plasma. The effect of bottom-emitted particles on the composition of gas-phase radicals increases with a decrease in the distance from the bottom surface and, accordingly, the etch characteristics of sidewalls in proximity to the bottom of an etched pattern is strongly affected by the bottom-emitted particles. However, information about the bottom-emitted particles, including species and amount of the particles and their influence on the etch characteristics of sidewall, is limited largely due to the lack of experimental methods for observing the phenomenon in a larger scale. In this study, we have analyzed particles emitted from different bottom materials using mass spectrometry at various bias voltages. We also examined the effect of the bottom-emitted particles on the etch characteristics of a SiO@sub 2@ surface located vertically and in proximity to the bottom surface. Ions of high energy sputter the steady-state fluorocarbon polymer layer covering the bottom to generate heavy and unsaturated fluorocarbon radicals, which contribute to the etch characteristics of the sidewall. As a result, the effect of bottom-emitted particles on the sidewall etching is profound under the conditions of high bias voltages and those allowing the formation of a thick steady-state polymer layer on the bottom surface.