Study On Temperature Control Method Of ArF Excimer Lasers Cavity

ArF excimer lasers are now widely used in medical,semiconductor processing,scientific research and other fields.The multi-cavity structure of the ArF excimer laser on the temperature stability requirements are higher.This thesis mainly studies the temperature control method of excimer laser,and designs a temperature control system.The main work and conclusions of this thesis are as follows:In this thesis,a kind of temperature control scheme is designed for the control of ArF excimer lasers with the characteristics of interference and change in the system.Through controlling the flow of PCW,we can achieve the aims.In addition,a flow balance valve,pressure balance valve and relief valve are used in the schemes to solve the problem that mutual influence of flow.Then,the hardware and software for system are designed.The transfer function of the proportional valve is established by means of the identification experiment.The transfer function of temperature and the flow,the relationship of the cavity temperature and the discharge power,the relationship of the cavity temperature and the PCW temperature are deduced by theoretical analysis.Through the above model,this thesis use a single closed loop temperature control structure.The control parameters are calculated by the D segmentation method and the sensitivity,so that the control system has a good sensitivity,amplitude and phase margin.Finally,the cascade control structure,feedforward cascade control structure and fuzzy PID-cascade control structure are designed to solve the shortcomings of single-loop control which can not suppress the flow disturbance.The temperature control system of the excimer laser is gradually getting better,which can fit to flow interference,repetitive frequency interference and changing parameters of object.At the same time,the simulation of the algorithm are carried out to prove that it can complete the control index of ± 0.2 ? and has certain robustness.