The system's high-speed tuning unit combines a high accuracy non-rotary type vacuum variable capacitor (VVC) with a linear actuator. Plasma is shifted readily towards a more stable domain even during the plasma arc -- or even in the event of an abnormal arc. Since the VVC has no rotating components there are no malfunctions from friction and burning. These innovations remarkably improve operational reliability The sensor circuit uses a narrow band frequency-selective impedance detection system for automatic matching. This circuit offers excellent suppression of miss operation and/or miss detection caused by spurious components resulting from non-linear load conditions associated with plasma generation or from interference caused by multi-frequency feeding. Tuning unit Click here for large image. Highly stable and accurate output power is maintained by a double loop with a real-time RF output control system. In order to cope with impedance variations during plasma transition and to ensure stable and accurate output power, the system uses both a digital power loop system and high-speed DSP. Each RF and its matching unit has a serial port (RD- 232C). By using this port and a PC data logger, it is possible to obtain and record various on-duty performance parameters -- such as output power, power supply voltage, current, cooling water temperature. The automatic matching process locus can be displayed on the PC screen to monitor and record matching status in smith chart formats. With optional application software, self-diagnostic tests can be used to for trouble-shooting, using PC data. Smith chart : Matching process Click here for large image. Ordinary solid-state RF power supplies are designed to protect the circuit elements from damage caused by abnormal load conditions. This protective functionality, however, can disrupt output power and operation -- with the plasma state losing uniformity and semiconductors in the power amplifier unit breaking down. JRC's new system, on the other hand, uses high-voltage power MOSFETs in the power amplifier unit. Using constant-current type power amplification circuitry, this new concept system offers various advantages including the dispersion of reflected power and thermal stress, the suppression of undesirable modes such as abnormal oscillation, and the prevention of system breakdowns due to abnormal load situations. In conventional systems, system failure activates an alarm circuit, halting the affected process -- with an effect on the entire production process. The JRC system offers three predefined levels of operation, An internal processor continuously monitors all system parameters, and displays either "Normal", "Tolerance", or "Alert" on a PC screen. "Tolerance" allows continuous operation. When potential problems are within specified operational tolerances -- the predicted alarm range -- and troubleshooting sessions can be scheduled using self-diagnostic tests and the like at a later time -- for example, between production sessions. The electrode surface voltage and impedance transition, from excitation to matching status, are calculated by using chamber parameters: size, permittivity, etc. Consequently the equipment design for optimum matching is possible. Chamber Simulation Click here for large image.