Study On The Polarization Aberrations Of Projection Lithography Lens

In recent years,the domestic integrated circuit industry has developed rapidly with the popularization of smart products,and the domestic integrated circuit market has become a major market for global integrated circuits.However,the development of integrated circuits in our country started relatively late,and a large number of chips rely mainly on imports.Especially in the manufacturing technology of integrated circuits,there is a obivious gap with foreign countries.The core of the semiconductor integrated circuit manufacturing process is the lithography machine.The foreign immersion lithography machine has already achieved industrialization,and our country lags behind.From the perspective of national strategic economic security,the catch-up and surpassing of integrated circuit technology is imminent.Therefore,it is of great significance to independently develop high-resolution projection lithography objectives.However,with the increase of the resolution of the objective lens,the numerical aperture of the lithography objective lens is increasing.In the case of high numerical aperture,the influence of polarization aberrations on the imaging quality of the projection lithography objective lens can not be ignored.Therefore,it is necessary to deeply study the polarization aberrations in the lithography objective lens.Compared with the conventional wavefront aberrations,the polarization aberrations are much more complicated.The research on the polarization aberrations of the objective lens at home and abroad mainly focuses on the characterization and imaging effects,but there is less research on compensation and measurement of polarization aberrations.For the projection lithography objective lens,it is necessary to form a systematic description theory of polarization aberrations,and to use the description theory to study related problems in compensation and measurement.This article relies on National Science and Technology Major Project to carry out research on polarization aberrations for high NA projection lithography objectives,mainly including the following research content:First,the description theory of polarization aberrations.In order to obtain the Jones matrix which describes the polarization aberrations of the objective lens,polarization ray tracing needs to be performed.For this reason,some researches on polarized ray tracing have been done in this paper.Both the Jones matrix and the Mueller matrix lack physical intuition and need to be mathematically decomposed.For Jones matrix,singular value decomposition and orientation Zernike polynomials decomposition are studied.For Mueller matrix,this paper proposes a new method based on homomorphism mapping in group theory,which can decompose nondepolarizing non-singular Mueller matrix and obtain polarization parameters such as diattenuation and retardation.The singular value decomposition and orientation Zernike polynomials decomposition of Jones matrix,together with the Mueller matrix decomposition method proposed in this paper,constitute a theoretical system for describing the polarization aberrations of lithography objective lens.Second,polarization aberrations compensation.In high NA projection objectives,some of the optical elements will use CaF2 crystal material,and the retardation introduced by the intrinsic birefringence will degrade the imaging quality,so the retardation needs to be compensated.In this paper,the intrinsic birefringence of CaF2 is studied.A new index based on orientation Zernike polynomials is established to describe the value of retardation.A method based on particle swarm optimization to rotate the CaF2 lens to compensate for the retardation in objective lens is presented,and a simulation is provided to validate the method.Third,polarization aberrations measurement research.In the development of lithography objective lens,polarisation aberration needs to be measured in order to obtain its polarization properties.In this paper,based on the measurement principle of Mueller matrix polarimetry,and optimized by condition number,the scheme of measuring the objective Mueller matrix is determined.Error simulation analysis was performed and the tolerances were assigned.A method for calibrating system errors was proposed,and simulation experiment shows that the measurement accuracy is improved after calibration compensation.The study results of this dissertation could be helpful for the development of high NA projection lithography objectives.