Electrical Variable Capacitor of Resonance type with improved Power Density for Plasma System

As semiconductor technology advances, etching processes demand higher precision and deeper etching depths. In these processes, impedance matching networks are used to improve etching accuracy. Traditionally, Vacuum Variable Capacitors (VVC) have been widely employed in impedance matching networks. However, due to their mechanical operation, VVC struggles to keep up with the rapid changes in plasma impedance, reducing etching precision and making it difficult to meet the increasingly stringent process requirements. To address this issue, Electrical Variable Capacitors (EVC) have been proposed. EVC, which operates electrically using switches such as MOSFET, provides capacitance adjustment speeds over 1000 times faster than conventional VVC, enabling $\mu$ s level adjustment speeds suitable for high-precision processes. However, conventional EVC circuits have the drawback of requiring additional components such as diodes and external power supplies, which increase circuit size, cost, and complexity. To overcome these issues, this paper proposes a new EVC design that is smaller, simpler, and more cost-effective. The performance of the proposed circuit was experimentally verified using a setup simulating semiconductor process. Therefore, the proposed EVC is expected to serve as a next-generation impedance matching network, effectively replacing VVC systems.