Design and Implementation of 13.56MHz, 600w Match Box for RF Plasma Generation

Plasma chamber is an electrical load with time varying characteristic, its impedance varies from the start to the end of the process. RF generator must see a pure 50 ohm load during the whole process at its output in spite of the varying condition of chamber’s electrical load. To cover that measuring of a proper parameter like VSWR and applying proper changes to the elements of MB is essential. In order to match plasma chamber’s electrical load to output impedance of RF generator, design and implementation of a MB with the power transmission of 600W at the frequency of 13.56MHz has been done. In MB, an Ltype network with two varying capacitors and a constant inductance has been used as the matching impedance network. Also a VSWR meter as a matching sensor, two servo motors as actuators for application of varying capacitors has been used. As a matching algorithm the minimum VSWR algorithm has been applied.