The Research On The Generation And Testing Method In A Polarization Illumination System

Numerical aperture and exposure wavelength are the key influence factors oflithography imaging resolution.Using large numerical aperture and short exposurewavelength will get high resolution and contrast ratio, but the polarization effect willbe introduced when using large numerical aperture, and it affects the performance oflithography more significantly. In order to study the performance of the projectionoptical lithography, it is very urgently to research the polarization. According to thespecific mask pattern, using the corresponding polarized beam (or polarization-mode)along with the off-axis illumination will improve the resolution and the imagingquality of the illumination system.Therefore, the research on the generation of specialpolarization modes and its conversion methods become more and more important. Inthis paper,we studied the generation and testing method of typical polarizationillumination modes(X polarization,Y polarization,X-Y polarization,Y-X polarization，radial and azimuthal polarization) in a lithography illumination system, the mainworks are listed as follow:(1)In order to study the development of the polarization illumination, weanalysised the advantages and disadvantages of various realization methods afterreading a lot of references about linear polarization mode、radial and azimuthalpolarization mode.(2) Design and simulation analysis of typical polarization modes.On the onehand, In order to produce linearly polarized lights with high degree of polarization(DOP) and purity, the polarization purification device based on the wave-plate stackwas designed.And the expression of DOP for the output beam was derived by themueller matrix of the device. The results show that,the DOP and energy utilizationwill be improved by making full use of the reflected s polarization of wave-plate stack.on the other hand, the design parameter of segmented wave plate was determined byestablishing the model of X-Y polarization,Y-X polarization，radial and azimuthalpolarization in ASAP(Advanced Systems Analysis Program).(3)Designed a testing scheme for the three kinds of polarizers. Finally, we useddivision of amplification method to measure four stokes vectors of the output beamsSimultaneously by studying the testing method of various polarizationperformance.And then calculated the DOP. (4) Experimental Verification. According to the designed testing scheme,we setup the experimental platform to test the polarization performance such as DOP of thedesigned devices.(5) Error analysis. The theoretical analysis mainly considered the number, thethickness of the wave-plate stack and the incident angle.