Production of 1-m size uniform plasma by modified magnetron-typed RF discharge with a subsidiary electrode for resonance

A large-diameter uniform plasma of 1 m size is produced using a modified magnetron-typed (MMT) RF plasma source at the frequency of 13.56 MHz. The construction and operation of the MMT RF plasma source are very simple and we can place two substrates simultaneously. To achieve an efficient production of high density plasma, a parallel resonance circuit is connected to one of the substrates which acts as a subsidiary RF electrode controlling the plasma parameters. In the case of the resonance the plasma density increases to approximately three times as much as that in case of non-resonance. The plasma density reaches ∼ 1 × 10¹¹/cm³ in Ar at 1 mtorr when the RF input power is 2.8 kW. The MMT RF plasma source provides a plasma with uniformity within several percent over 1 m in diameter in front of the substrate in the low gas pressure regime.