Research On Temperature Control Of Air For Sealing Immersion Flow Field In Immersion Lithography

Immersion lithography is currently the only semiconductor manufacturing equipment that is widely used in 45 nm integrated circuit production lines.Dynamic seal of immersion flow field is one of the core technologies of immersion lithography.Air as an important medium for seal,its temperature will directly affect the immersion system and lithography environment.In order to control the temperature of the air for sealing immersion flow field,following research work is completed in this thesis:According to the principle of air sealing in immersion flow field,the temperature change of the gas into the immersion unit was analyzed by fluid simulation,through which we can get the specific requirements of system with certain adaptability.The relationship between the temperature,humidity,cleanliness and pressure flow of the sealing gas is analyzed synthetically.The air supply system is designed,in which the air temperature control scheme is put forward.An air temperature control scheme based on gas-liquid heat transfer is proposed.First,this thesis analyzes the strength and weakness of direct temperature control method(heating and cooling)and indirect temperature control method(heat exchange).Considering the characteristics of small flow rate and high precision of the air temperature control system,the way based on heat exchange is more suitable.Then by analyzing the static characteristics of the heat exchanger,we choose to change the temperature of water to control the heat transfer quantity.To control the temperature of water,a scheme based on the circulating circuit is put forward.And the advantages of the scheme are anatomized.The results show that it can improve the inertia of the temperature control system and ameliorate the control characteristics of the system.Based on models established by mechanism,a temperature control algorithm was proposed.In view of the characteristics of multi-interference of temperature control system,a cascade control structure is adopted.In order to improve the robustness of the temperature control system,a method of setting the parameters of the cascade PID controller based on maximum sensitivity is introduced.The main and a secondary controller choose different maximum sensitivities according to requirements of the system.The design of the air temperature control equipment was preliminarily completed in this thesis.To complete the electrical design,conceptual design of control system was done and Electrical Schematic Diagram was drawn up.The mechanical design is made of mechanical frame design,liquid layout design and electrical structure design.The simulation results show that the temperature control system has good anti-interference ability and strong robustness,and it will be applied to temperature control of air for sealing immersion flow field in immersion lithography.