Precision Motion Platform For High-precision Pid Controller

Ultra-precision motion stage is one of the key components of the step&scan lithography. With the continuous pursuing to high quality and high efficiency of the semiconductor lithography equipment in production, the motion stage is developing further towards high velocity and high acceleration. Thereby, how to improve the precision of the motion stage and guarantee the lithography quality of the related productions, is becoming an urgent problem in the process of developing semiconductor lithography equipments.The research contents in this paper come from the project of National Natural Science Foundation and Shanghai Municipal Science and Technology commission "Damping and Isolating Vibration Technology for Precision Machine". This paper takes the motion stage of the vibration isolation platform as the research object. According to the research task and the research status of the project at home and abroad, theoretical study and computer simulation analysis and experimental study are taken as the research means in this paper. Simulation analysis and experimental study on compound PID control for the motion stage are taken by using Fuzzy control theory in order to reduce the effect of nonlinear disturbance of the macro-motion table. Basd on the character of the motion stage repetitive control is analyzed to reduce the tracking error of the system.The main contents of the degree thesis are as follows:First, the mathematics models of the macro-motion tables for lithography wafer stage and stencil stage are established after analyzing the mathematics models of the components. The simulation models can be used for designing and testing the control methods of the macro-motion tables.Second, in order to reduce the effect of nonlinear disturbance of the macro-motion table, a control model of incremental fuzzy PID control is established based on the character of the three parameters of PID control. Simulation tests and experiment results indicate that the dynamic performance and positioning accuracy of the system adopting the suggested compound controller is much better than common PID control method and the designed controller can excellently maintain the dynamic performance and positioning accuracy of the system with the parameters of the system being adjusted dynamicly.Third, in order to reduce the tracking error of the system, based on the character of the macro-motion table for stenci stage, the paper puts up a control model of PID control with feedforward compensation and repetitive control compensation for the position controller. Simulation tests using MATLAB software indicate that the tracking performance of adopting the suggested compound controller is better than common PID control method and the time constant of the lowpass filter for the repetitive controller affects the performance greatly.All above mentioned research contexts, methods and coclusions are helpful to the research on motion control of the step&scan lithography.