Research On Polarization Aberration Of Hyper-NA Optical System

Hyper-NA optical systems generally refer to Hyper-NA projection lithography objectives.For lithography machine,the Hyper-NA projection lithography objective is the most important component,and its imaging is decisive to determine the performance of lithography.Polarization aberrations can affect the imaging of optical systems,such as reducing imaging contrast.In order to improve the imaging quality of Hyper-NA projection lithography objectives,it is also necessary to optimize the polarization aberration of the optical system except controlling wavefront aberrations.Studying the polarization aberration of Hyper-NA optical systems is of great significance for developing projection lithography.Therefore,this paper takes NA1.35 projection lithography objective as an example to introduce systematically the polarization aberration theory of optical system,and analyzes and optimizes the polarization aberration of optical system.Firstly,the theory of polarization aberration is introduced.Hyper-NA optical system imaging is described using a vector imaging model,which uses a vector imaging model to derive the concept of optical system polarization aberrations.Describes the method of describing polarization aberrations using Jones pupil.The SVD decomposition is used to decompose the Jones pupils into a physical pupils,and the diattenuation and retardation are used as evaluation criteria for polarization aberration.The calculation method of optical thin film properties is introduced,and the Jones matrix expression of optical film is given,which provides theoretical support for analysis and design of optical films.Secondly,the factors causing the polarization aberration of the optical system are analyzed,and the corresponding theoretical expressions are derived.Third,the polarization aberration of NA1.35 projection lithography objective lens with conventional film is analyzed,and a method for designing a multilayer film for optical components based on the maximum incident angle of light is proposed to optimize the polarization aberratioin of the optical system.A corresponding multilayer film was designed for each optical surface according to the optimized conditions of the film.Compared with NA1.35 projection lithography objective lens with the conventional film,diattenuation and retardation of NA1.35 projection lithography objective lens with optimized multilayer are significantly reduced.That is,the polarization aberration of the optical system is optimized.Imaging contrast is improved by decreasing the polarization aberration of optical system.The Prolith lithography simulation software is used to simulate the exposure performance of the NA1.35 projection lithography optical system of the conventional films and the optimized films.The result shows that the imaging contrast of the optical system with optimal films is improved,and the effectiveness of the polarization aberration optimization method is proved.