Rf Plasma, Dust Particles And Dust Void Experiments Study

Charged dust particles exist extensively in plasmas produced in space, laboratory as well as for plasma processing. The growth and charging of dust particles and their dynamics in plasmas have attracted much attention in the recent years since dust contamination is recognized as a serious problem in plasma etching processes of integrated circuits. Dust particles are investigated in the dissertation are created in situ in RF discharge of mixture reactive gases of silane and ethene. There are two focus included as the following two topics:(I)The measurement of equilibrium charge of dust particles in the plasmas By studying the forces acting on dust particles at the equilibrium position, where, the electric force and gravity force are importantly considered, the equilibrium charge of dust particles can be presumedly calculated according to the relation of the forces. The calculation results indicate that the equilibrium charge of dust particles is in range of 102e-105e, which is consistent to the previous results of other researchers.(II)The experimental dynamics investigation of dust cloud and dust void The growth processes, levitation and instability of dust particles in the RF sheath, especially the formation of dust void and its behavior with varying external parameters such as pressure, RF power and the configuration of the RF electrode are investigated. Experiment results indicate that the volume of dust cloud and the diameter of dust void gradually increases with gas pressure till pressure gets to a critical value, and then the increase grows slowly; the diameter of dust cloud and dust void vary periodically with RF power; the shallow hole centered at the RF driving electrode is irrespective of the void shape, but the size affects the diameter of void; during the void formation some instabilities (rotation, shrink, expansion) appear.