Design And Implementation Of Communication In Immersion Control System

With the liquid refractive index is higher than that of gas, immersion lithography improves the lithography resolution by filling immersion liquid between silicon wafer and the final lens. Immersion lithography is the best inheritance of traditional dry lithography, so it has been paid much attention in the semiconductor industry. In immersion lithography machine, the immersion control system is a very important subsystem, which produces the immersion liquid and realizes injection and recovery of immersion liquid. The function of immersion control system is implemented by three subsystems, which are pure water system, transportation control system and attitude regulation system. When immersion control system is integrated in immersion lithography machine, the master control system receives messages from host and controls these subsystems to collaborate. Since robust control process is based on message exchange, effective and reliable communication is one of the most important factors of integration in immersion control system.In this thesis, the immersion control system which produces the immersion liquid and settles stable immersion flow field was studied, and the communication in immersion control system was mainly designed and implemented, and the main completed contents are briefly stated as the followings:1. The hardware and software in each subsystem were analyzed, and the feasibility of industrial Ethernet was analyzed on this basis. Furthermore, the hardware and software framework of communication in immersion control system were designed. And some methods which improve the reliability of communication were put forward.2. Six system states of each subsystem were designed, and the communication protocol in immersion control system was designed on this basis. Meanwhile, according to the message priority scheduling requirement of immersion control system, the message scheduling based on mixing static priority and dynamic priority was designed, which improves the flexibility of control and real-time performance of message transportation.3. Above the communication framework and protocol, the communication program was accomplished by the modular design of software, main flowchart design of program, the programming of each module, the design of application programming interface and so on.4. According to the communication requirements of immersion control system and the designed communication protocol and scheme, the function and performance of communication program were tested by message communication test, communication state monitoring test, network switching test, delay time test, packet loss rate test, etc.