| Summary: | 碩士 === 國立清華大學 === 工程與系統科學系 === 105 === Capacitively coupled plasma (CCP) sources have been widely used for material processing. The purpose of this study is to investigate the effect of trench on the plasma properties. In this study, CCP discharges have been investigated by fluid model numerical simulations (CFD-ACE+, ESI Corp.).In order to produce the hollow cathode discharge (HCD) to tune the plasma distribution and uniformity. This study is divided into two parts, respectively, using Argon and Carbon tetrafluoride, the discharge is generated by a 27 MHz radio frequency power.. The two-dimensional fluid model was used to simulate the plasma behavior in the plasma etching system, and the correlation between the plasma properties and the operating parameters was compared by analyzing the simulation results.
The simulation model takes into account 3 gaseous species and 4 reactions for Ar. Simulation results show that, for typical operation conditions(electrode without trench),the electrons ,is around 1.11017 1/m-3,are evenly concentrated in the plasma chamber, and the sheath width on the grounded electrode is 1.2 mm. When a trench of dimension 4 mm x 8 mm is added, simulation results reveal that there is a significant modification the spatial profile of the plasma density(2.41017 1/m-3), as a result of the hollow cathode effect：Simulation results show that, for typical operation conditions, the plasma density of the CCP is enhanced by the “hollow cathode“ effect of the trench if the width of the trench is wider than twice the thickness of the plasma sheath, as expected. In addition, simulation results also demonstrate that the plasma uniformity can also be tailored by the hollow cathode effect due to a grounded electrode (GE) trench.
The simulation model takes into account 11 gaseous species and 43 reactions for Ar. First, the basic plasma model (without trench) was established. The simulation results show that the F- density is concentrated in the central a very narrow region with a large spatial density gradient, so the numerical convergence results is not good . We have been tested: adjust the convergence range and change the initial value of the plasma ... but there is still the simulation calculation problem.
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