Research On Nanoscale Precise Control Of Piezoelectric Actuator And Its Application In Lithographic Projection Lens

The rapid development of semiconductor technology represented by integrated Circuit(IC)has promoted the progress of society.With the development of critical dimension of IC to less than 30 nm,as a core component of IC manufacturing photolithography technology,lithographic projection lens' s aberration has more and more prominent influence on the imaging quality.As the core driving device of the adjustment mechanism for the optical lens,the piezoelectric actuator can compensate aberration such as astigmatism,spherical aberration and distortion in real time,and thus greatly improve the imaging quality of projection lens.Hence,this paper adopts the following methods and conducts deep research on modeling and control of piezoelectric actuator,which realizes micrometer displacement control in less than 0.15 s with accuracy better than 20 nm and satisfies the requirement of precise aberration compensation for the lithographic projection lens.1.The working principles of capacitive displacement sensor,optical grating encoder and laser interferometer are analyzed,their displacement measurement noises are tested in the experiments respectively,and their application occasions for nanoscale precise closed loop control are obtained.2.The hysteresis characteristics of stacked piezoelectric actuators are studied,a fuzzy hysteresis model is established,an adaptive fuzzy internal model control algorithm is designed,its stability is analyzed and the closed loop precise control experiments are conducted for sinusoidal trajectory tracking.In addition,a phase shifter system driven by a stacked piezoelectric actuator is designed.With the help of the displacement measurement and correction of an external high-precision laser interferometer,a semi-closed loop control method is used to achieve the 3nm repeatable positioning accuracy.3.The relationship between the displacement and voltage of the walking piezoelectric actuator in quasi-static condition is analyzed and motion characteristics under different driving voltage waveforms are compared.The dynamic linear model of the walking piezoelectric actuator system is established and then identified based on experimental data of frequency response.The path planning,velocity feedforward,PID feedback and repetitive learning control algorithm are designed to conduct the closed loop precise control experiments for point-to-point motion and trajectory tracking of the walking piezoelectric actuator system.4.The applications of piezoelectric actuators in lithographic projection lens are analyzed.For nanoscale precision displacement adjusting control applications in the aberration compensation axial adjustment mechanism and six degrees of freedom adjustment mechanism,the stroke range,displacement resolution,settling time,steady-state error and surface shape change of the optical element during closed loop adjustment control are studied respectively.