[12a-N102-1~9] 8.2 Plasma deposition of thin film, plasma etching and surface treatment

△ [12a-N102-3] Behavior of active species in the cycle process modulated Ar/C₄F₈/SF₆ gases - 2

〇(M2)Taito Yoshie¹, Takayoshi Tsutsumi², Kenji Ishikawa², Masaru Hori² (1.Nagoya Univ. Eng., 2.Center for Low-temperature Plasma Sciences, Nagoya Univ.)

Keywords:Plasma etching, Semiconductor, Gas modulation cycle process

Although it has been shown that there are few shape abnormalities by a gas modulation cycle process that repeats side wall protective film deposition (C₄F₈) and hole bottom etching (SF₆) to form Si pores with a high aspect ratio, it is an active species that realizes it. The behavior of is not elucidated. In this study, the time course of electron density during the cycle of gas-modulated Ar / C₄F₈ plasma and Ar / SF₆ plasma was measured by a surface wave probe for high-speed time-resolved. As a result, we found that Ar / C₄F₈ plasma and Ar / SF₆ plasma differ only in the gas mixture and the other conditions are the same, but there is a difference in the change in electron density depending on the gas composition that stays after gas switching. It is mainly the effect of the amount of negative ions in the plasma due to the retention of SF₆, and the plasma simulation of the device model was performed to show the guideline for optimizing the process conditions such as gas modulation.