9:30 AM - 9:45 AM
△ [12a-N102-3] Behavior of active species in the cycle process modulated Ar/C4F8/SF6 gases - 2
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.