## 3 Plasma Sources
### Dielectric Coplanar Surface Barrier Discharge (DCSBD)  
The dielectric coplanar surface barrier discharge (DCSBD) source is a specific type of DBD. The DCSBD is an innovative arrangement designed to produce a large-area, uniform plasma layer that is open to the environment at atmospheric pressure. The main difference is that, in the case of DCSBD plasma sources, the discharge is generated on the surface of a single dielectric plate. All electrodes, typically in a series of parallel metallic strips or an interdigitated pattern, are on the same plane and are therefore coplanar. In DCSBD plasmas, all the electrodes, which are typically formed from a series of metal strips having a parallel or an interdigitated pattern, are embedded within or on one side of a single dielectric plate. Similarly as was the case in DBD plasmas, the electrodes in the system are covered by a dielectric material for which the barrier prevents the electrical discharge from turning into a hot, high-current arc, thus limiting the current flow, keeping the plasma stable and cold. The AC voltage is applied between adjacent electrode strips, creating a significant electric field to be formed. This strong electric field at the edges of the electrodes causes gas breakdown on the dielectric surface and forms a plasma, which then spreads laterally over the surface. The plasma forms as a thin, uniform layer on the surface of the dielectric, spreading across the area above the electrodes. Thus, unlike DBD plasmas, in this case, the plasma is not formed in the gap between the electrodes, but rather on top of them. The key advantage of a DCSBD plasma is that it produces a very uniform, diffuse, and stable plasma layer at atmospheric pressure, especially in air. The plasma is completely open and accessible on one side, which leads to it being used for treating large, flat surfaces that are passed over the plasma body. Figure 4 provides a schematic representation of a DCSBD plasma system. The dark-grey area represents the ceramic base layer, while the light-grey area presents the dielectric layer. Other features include orange and green \begin{table}
\begin{tabular}{c c} \hline
**Parameter** & **References** & **Parametric Score** \\ \hline Plasma Stability & The plasma from this source generally has lower stability than comparable MW or RF sources. However the stability of DBD plasmas depends also on the ambient setting. At atmospheric pressure, DBD plasmas often operate in a filamentary mode, where the discharge consists of many micro-discharges (filaments). These filaments are spatially and temporally random, but are stabilized by the dielectric barrier. At lower pressures, DBD plasmas can achieve a more homogeneous (glow-like) discharge, although DBD plasmas are not generally used in vacuum conditions, apart from in a few limited applications [55]. \\ \hline Plasma Energy Density & DBD plasmas typically operate at lower energy densities compared with RF plasmas. The energy density in DBD systems is influenced by the dielectric material and the applied voltage, which limits the current and prevents acting [61]. \\ \hline Electron Temperature & The electron temperature in DBD plasmas typically ranges from 1 to 10 eV [18; 27; 62]. \\ \hline \end{tabular}
\end{table} 
Table 7: _Cont._structures, which represent the electrodes that are alternatively connected to the positive and negative sides of a high voltage generator. The plasma formation is seen as the yellow-shaded zone formed above the dielectric layer [63]. The reviewed literature has indicated that DCSBD plasmas are mostly used under atmospheric conditions as a fast, cheap, and effective method to simultaneously clean and activate a silicon surface. The oxidation it causes is a key part of the activation process that makes the surface highly useful for subsequent coating steps. While this is desirable in the case of wafers, it would be counterproductive in the case of lead frame cleaning [63]. Table 8 provides the grading of parameters with respect to DCSBD plasma sources.