Design And Algorithm Research Of Precision Temperature Control System For Lithography

At present, the semiconductor manufacturing process has come in20nm field andphotolithography machines have achieved in extreme ultraviolet lithography technologyphase. For the imaging accuracy requirement, projection lens must have a goodtemperature stability of±0.01℃. Precision temperature control system is the equipmentthat is used for control the index of photolithography machines. China began developingsemiconductor industry in the early21th century. And now our country is still at startingstage. The performance of our semiconductor industry is much lower than mostadvanced countries of the world. Now, it is very urgent to develop semiconductorlithography equipment of our own. The subject is supported by the national science andtechnology major project "193nanometer photolithography machine" and the matcheditem of "Cooling water temperature control system of the photolithography machineprojection lens". In this paper, several typical temperature control algorithms areanalyzed systematically in theory, and the computer simulated experiments are done.In the second chapter, we designed the system of temperature control, the designfocuses on three aspects: structure of a system, hardware control, control theoryDynamic behaviour and physical characteristics of controlled plant are analyzed indetail. In the present study, the mathematical model of control plant derived by usingtheory modeling and system identification technology.In the third chapter, typical PID control and Smith predictive control aretheoretically analyzed for this large time-delay system. And simulated results areobtained. Compare the advantages and disadvantages of two methods, we advance anddesign a multimode control which combined P control, self-tuning fuzzy PID control, PIcontrol. It is very significant for performance index and parameter self-tuning oftemperature control system. The simulated results demonstrate that the multimodecontrol is satisfied, and the control algorithm is helpful for actual hardware design later.In the fourth chapter, according to the design specifications of the temperaturecontrol system, we design the hardware control system and control program. Thecontrol system consists of PLC, intelligent temperature controller, thermoelectric cooler module, heater module, high precision temperature measurement system and safetyprotection module.In the course of researching, we have assembled and debugged the temperaturecontrol system which we designed. Experimental results of different test plan show thattemperature control system is satisfied with requirement of designed. This system has agood stability and the control precision of temperature is less than±0.01℃.