Electrode material effect on electron density in cpacitive coupled plasma

Abstract

Capacitively coupled radio-frequency discharge has been widely used as one of the plasma processing sources, because the geometry of capacitive coupled plasma (CCP) is very simple and easily discharged. Especially, etching and deposition are accounted for the largest part of plasma processing and improving the efficiency of processing is considered to be an important subject. Furthermore, plasma interaction with material is an important effect of plasma processing, because various materials are used in plasma processing, and materials of chamber wall and wafer surface can influence plasma. Changing the material of electrodes can affect the plasma characteristics of capacitively coupled discharge. The etch rate and deposition rate are closely related to the ion and radical flux density of the plasma. If the electrode material is different at the capacitively coupled discharge, it can affect the ion and the radical flux density because the interactions with the plasma depend on the kind of materials. [4] In order to improve the etching rate, selectivity, and deposition quality, it is important to know the effect of the electrode material on the plasma and how to control the process. The experiment was produced in a parallel-plate capacitively coupled plasma chamber in the shape of cylinder. We used three electrode materials for experiments such as aluminum, aluminum oxide ($Al_2O_3$), and stainless-steel. The use of different electrode materials allowed to vary the influence of secondary electrons. The measurements of electron density and electron temperature are indicated with varying pressure, voltage, and power. The effect of γ electron of the plasma discharge and the mode transition of the plasma are investigated.