Modeling Analysis And Optimal Design Of Immersion Supplying System In Immersion Lithography

The precise control of the injection flow rate plays an important role in the manufacturing equipment of the semiconductor IC. The flow fluctuation of the immersion liquid will cause its pressure fluctuation and then the appearance of the tiny air bubbles. It will also cause the turbulence of the immersion fluid field layer. These have impacts on the quality of lithography and even lead to etching failure.In addition to the flow index, the lithography system has strict requirements on the liquid temperature. The temperature fluctuation will cause the surface strain of silicon wafer and make the resolution reduce, affecting the quality of lithography. The design of traditional liquid system separates flow and temperature control, resulting in repulsion phenomenon and ineffective regulation in the integrated process.At the same time, the flow requirement of the core component immersion unit can be regarded as variable system. So it is necessary for the liquid injection system to have a certain degree of adaptability. But traditional flow control design, such as PID control can meet the system requirements after setting as well as fail to have the function of self-adaptability.According to the problems in the process of the current injection system design and the self-adaptive requirements in control, the topic puts forward the complete process design and introduces the fuzzy control to meet the requirement for self-adaptability. The fuzzy PID is verified by the simulation and then implanted into the experimental platform for actual control. Specific works are as follow:1. Analyzing the reasons of the function repulsion in the design of traditional liquid injection system and putting forward improved process principle. Descripting and decomposing the function of each stage in the process.2. According to process principle, the corresponding design works including device and material selection, mechanical structure design, electrical wiring design and control process design are done and then building the experimental platform.3. Introducing the fuzzy control theory and building the fuzzy PID control method after combining with PID control. The simulation model is established by the MATLAB software and then the excellent performance of the fuzzy PID is verified.4. Setting up the experimental test platform which is including integrated flow control unit, pressure transmitter, flow meter, proportional control valve and other core components and the function of basic fuzzy PID control in PLC controller.5. Analyzing the different control effect of the experimental system in fuzzy PID and conventional PID control mode, especially the optimization effect of overshoot and response time and verifying the self-adaptability of fuzzy PID control mode.