Designing the Topology of a Unipolar Pulsed-DC Power Supply using the Open-source Scilab/Xcos Software for a Low-cost Plasma Etcher

We proposed a design topology for a unipolar pulsed direct-current power supply to produce low-cost reactive plasma etcher system. The design was simulated by a block diagram method using the open-source software Scilab/Xcos, and the results were validated by prototyping the power supply. In the topology, the snubber circuit and the RLC circuit play a critical role in producing a smoother pulse waveform and regulating the characteristics of the plasma current. Their optimized parameters can provide well-controllable duty cycles in the voltage output of the power supply. Moreover, the effect of the duty cycles on the performance of the power supply is analyzed. We found that the duty cycle can adjust the transient response of the plasma current as well as the density of the plasma ions. This aspect is useful not only for reducing the arcing effect but also for modifying the surface wettability of the treated substrates. As a result, the glass substrates treated with a 100% duty cycle becomes more hydrophilic, while those treated with a 20% duty cycle tend to be more hydrophobic.