Details

Autor(en) / Beteiligte

• Baek, Kye Hyun
• Lee, Eunwoo
• Klick, Michael
• Rothe, Ralf

Titel

Comprehensive understanding of chamber conditioning effects on plasma characteristics in an advanced capacitively coupled plasma etcher

Ist Teil von

• Journal of vacuum science & technology. A, Vacuum, surfaces, and films, 2017-03, Vol.35 (2)

Erscheinungsjahr

2017

Link zum Volltext

Quelle

American Institute of Physics

Beschreibungen/Notizen

• An advanced capacitively coupled plasma etcher with two frequencies and additional direct current is characterized with complementary sensors. Due to the restrictive boundary conditions of the manufacturing environment, which the authors had to take into account, applicable plasma sensors are limited. Thus, the plasma parameters depending on the center, wall, sheath, and cathode regions are extracted separately based on the tool parameters, optical emission spectroscopy, and self-excited electron spectroscopy. One main target of this investigation is a cross verification of complementary sensor data and a deeper understanding. Due to the complex chamber setup, the authors use a chemically simple system of an Ar plasma with a blank Si wafer as the substrate. It is found that the removal of SiO2 and sputtering Si from the cathode and wafer changes the chamber condition and thus causes changes in the plasma characteristics. The established plasma process model comprises a change in secondary electron emission caused by changing the surface condition and a subsequent change in collisionless electron heating, in particular, in the case of applied low frequency power. Current electron heating models and conditioning models are used for cross verification of the plasma process model. It indicates that both chemical and electrical aspects to chamber conditioning should be considered in multiple frequency driven plasma etchers. The results presented in this paper are expected to contribute to the understanding of the interaction of the chamber conditioning effects and plasma parameters in advanced plasma etchers for sub-20 nm devices.