Design and Experiment of a Slotted Antenna Surface Wave Plasma Flood Gun

Abstract

In a modern ion implanter, plasma flood gun (PFG) is used to neutralize wafer charge during doping process, preventing the breakdown of floating wafers caused by the space charge accumulation. In order to obtain the PFG which can produce ribbon electron beams with the characteristics of high stability, high plasma density, no metal pollution and long life, studies at Peking University (PKU) are focused on surface wave plasma flood gun (SW-PFG) recently. A 2.45 GHz SW-PFG with a quartz plate and a series of metal slotted antenna arrays was designed and tested. Theoretical studies are carried out to optimize the SW-PFG structural parameters. The quartz plate thickness is determined as 15 mm. The size of the plasma chamber is 280 mm×150 mm×40 mm with a 280 mm×2 mm extraction slit. In the experiment, a relatively uniform argon plasma is obtained under the condition of gas flow rate of 2 sccm and input power of 800 W. In this case, the plasma distribution is studied by emission spectrum diagnosis and 73 mA ribbon electron beam is measured.