Research On Gas Temperature Control Algorithm Based On Variable Universe Fuzzy PI Control

The optical lithography tool is a key device for the manufacture of integrated circuits.The accuracy and stability of the gas temperature are important factors affecting its resolution and image quality.In order to achieve high accuracy and high stability of the gas temperature,it is necessary to study a temperature control algorithm having high accuracy,stability,and robustness.The main research work and conclusions of this article are as follows:Gas temperature control system has the characteristics of non-linear,time-varying,large time lag and multi-disturbance.For the needs of multi-temperature control targets,this paper proposes an optimized multi-target air ratio control adapted to the changes of the ambient temperature.The control structure reduces the influence of ambient temperature disturbance on temperature stability and solves the problem that multiple control targets cannot meet the temperature index at the same time.The “gray” identification method is used to obtain the model parameters of the temperature control system.Based on the above model,the servo air valve is used to control the air volume ratio,and a PI control algorithm that can eliminate the reverse mechanical clearance of the air valve is proposed.The Si temperature control algorithm is simulated using Simulink.The simulation results show that the algorithm can effectively make Both control targets reach the temperature setting.The temperature control algorithm is implemented using the.NET framework and tested on the experimental platform of the gas temperature control system.The experimental results show that the algorithm obtains higher temperature accuracy,but the system has a large overshoot,a long stabilization time.And lack of robustness.In order to solve the above algorithm problems,the variable universe fuzzy control algorithm was further designed and the temperature control algorithm was simulated.The simulation results show that this algorithm can effectively reduce the overshoot,shorten the settling time and improve the anti-interference ability.The variable universe fuzzy control algorithm was tested on the above platform for accuracy,stability,and robustness.The experimental results show that the algorithm achieves a temperature accuracy of ±0.04°C,and the short-term temperature stability can reach 10K/5min,which meets the requirements of the optical lithography tool for gas temperature control performance.