Research On The Control System Of High-order Aberration Compensation System For Projection Lithography Lens

Optical projection exposure technology is the most innovative lithography technology now,which possesses the fastest technological progress and is the widest applied in the research and development of the very large scale integration.At present,only ASML Corporation and Nikon Corporation have the ability to develop and massively produce high-performance projection photoetching machines in the international market,the development of high-performance projection photoetching machines in China starts relatively late and has very weak foundation,and each company has carried out strict technical blockade and patent protection for its core technology which seriously restricts the development of projection photoetching machines in China.High-order aberration compensation system is an important part of projection lithography lens,and there are mature research findings which are not disclosed abroad.There are little researches on high-order aberration compensation system of projection lithography lens in China,the gap exists in the technical level between the domestic and abroad researches,so that it has therotical meaning and application value to do some researches on high-order aberration compensation system.The paper carries out the researches about the control of the high-order aberration compensation system for projection lithography lens,which are as follows:1.Researches on the structure of the heating controlled deformable mirror and the principle of the high-order aberration compensation system.The principle of high-order aberration compensation system for projection lithography lens is proposed based on the theory of two-dimensional function discretization,the proposed principles are analyzed and simulated concisely,and the mathematical relationship between high-order aberration and the heating unit's power of heating controlled deformable mirror is pointed out.The topology of the heating controlled deformable mirror is designed based on the proposed principle of the high-order aberration compensation system,the micro-macro transfer circuit to connect the heating controlled deformable mirror and the print circuit board is designed,and the critical performance of the heating controlled deformable mirror is analyzed and verified by experiments.Finally,the architecture of the high-order aberration compensation system is presented,and the requirements of the output power of the heating unit in the heating controlled deformable mirror are put forward.2.Research on the driver system of heating controlled deformable mirror.The drive system of the heating controlled deformable mirror is proposed by the principle of Pulse Width Modulation,the system uses a voltage source to supply power,and the output power is controlled by the duty cycle of the switching circuit.The factors affecting the accuracy of output power are concretely analyzed in the design,and these factors are limited in the design.It is difficult to realize the voltage source in the design as the voltage source needs to possess the property of low internal resistance,so that the method to setup the nonlinear model of the analog circuit is proposed,then the design of analog circuit is transformed into the design of system stability analysis and system correction in classical control.This method is applied to the design of the power amplifier for driving piezoelectric stack actuators and has achieved excellent results,which proves that the proposed method is effective.3.Research on the power estimator of the heating unit for heating controlled deformable mirror.The power estimator is designed to realize the accurate control of the power of heating controlled deformable mirror,and the power estimator uses the output voltage to estimate the output power based on the circuit model.The errors of the power estimator are concretely analyzed in the design,it is definite that the AD circuit error contributes the most error,and the standard to chiose the sampling resistor is proposed.The power estimator is realized by FPGA logic,then its results is evaluated by some tests.The test results show that the systematic relative error of the power estimator is less than 1% and the peak to peak value of output random noise is about 0.020 m W,and these results prove that the performances of power estimator is in line with the requirements which are proposed by the system.4.Research on the high precision control of output power of the heating unit for the heating controlled deformable mirror.The control model of the system is established by analyzing the theory of the system,an adaptive PI controller is designed to reduce the influence introduced by the time-varying parameters in the model,the stability of the controller and the influence of parameter estimation error are analyzed,and the analysis results show that the designed controller is stable and the accuracy of parameter estimation can meet the requirements of the adaptive control.The controller is verified by Simulink Simulation,the method to choise the control parameters is discussed,and these analyses offer path to determine the parameters of the controller.The experimental results show the designed controller possesses the advantages of low computational complexity which is easily implemented by embedded system,the most concerned steady-state error is about0.002 m W when the input is step signal,the maximum steady-state output noise is about 0.030 m W,so that the designed controller can meet the requirements which are proposed by the high-order aberration compensation system.