Investigation On Deposition Conditions And Properties Of Fluorocarbon Films By Dielectric Barrier Discharge

The fluorocarbon films will be a potential material as the IC isolation medium, and it is becoming medium dielectric constant materials one of the rivalrous candidate to instead of the SiO₂ for the higher density and higher speed IC in the future because of its' lower dielectric constant and good thermal stability, the film will increase the speed and efficiency of IC. The dielectric barrier discharge (DBD) can produce non-equilibrium plasmas below or above atmospheric pressure.The merits of deposition of fluorocarbon films assisted in the DBD plasma may involve the simplicity of the experimental setup, the significantly lower consumption of the feed gas and the electric energy, as well as the large-area deposition on various substrates at room temperature. The C₄F₈-DBD plasma has been applied to deposit fluorocarbon (FC) films at atmospheric pressure and lower pressure in this work. The diagnosis of the film deposition plasma by using atomic force microscope (AEM), scanning electron microscope (SEM), X-ray photoemission spectroscopy (XPS) and contact angle goniometer is reported and the deposition mechanism is discussed.Large-area films with their diameter up to 60 mm were deposited by the low-pressure DBD C₄F₈ plasmas. It is found that the root-mean-square (RMS) is increasing with the increasing of the frequency of the power supply, also the root-mean-square (RMS) is decreasing whit the increasing of the discharge pressure. XPS is used for elemental and structural analysis of the deposited FC films. Increasing the discharge pressure from 25Pa to 125Pa leads to a significant increase in CF2 content and a concomitant decrease in CF₃ and crosslinking moieties. All deposited FC films are hydrophobic, with contact angles between 105°and 112°. The film deposition rates are plotted as a function of frequencies. The deposition rate increases from 81 nm/min to 152 nm/min when the frequency of the power supply is varied from 1 kHz to 7 kHz.DBD plasma at atmospheric pressure has been applied to prepare fluorocarbon films on silicon substrate from C₄F₈ and Ar mixtures. The influences of discharge gas compositions on film quality have been examined.