A novel distributed system for plasma immersion ion implanter control and automation

The high voltage and electromagnetic field environment poses a big challenge to a control system for plasma immersion ion implantation (PIII). The automation process must be immune to electric field interference produced by the high voltage power supply, modulator, radio-frequency or microwave plasma generator, MEVVA plasma sources, and so on. We have recently designed and installed a distributed control system, PIIIDCS, to automate the operation of our PIII facility. Programmable logic controllers are used as the field control stations because of their good anti-interference ability and good real time response. A DH-485 network is used as the communication link between the field controllers and the management station in order to improve the robustness and reliability of the system. The newly developed interface is designed to work in a graphic mode in Microsoft Windows 95. Test runs have shown that the system is reliable, flexible, and easy to operate. The development of this novel control system will expedite the development of commercial PIII instrumentation.