Research On UV Talbot Lithography Technology And Its Defect-repair Effect

The continuous development of aerospace,display lighting,biomedical and other applications has promoted the rapid progress of the preparation of periodic micro-nano structure.The requirement of the periodic micro-nano structure is more and more severe,which needs to meet large area,high precision,complex pattern,short preparation period and high yield.Traditional lithography is not able to meet the needs and faces serious challenges.The new micro-nano fabrication technology with high resolution and high yield has gradually became a hot research topic.Firstly,the thesis investigated the existing periodic micro-nano processing technology and Talbot self-imaging lithography.Different from conventional lithography,Talbot lithography does not need expensive optical imaging system.this technology directly use the self-imaging from Talbot effect to fabricate periodic objects,and can repair defects existing in periodic micro-nano array.But the focal depth of Talbot self-imaging is shallow and the limitation of the mask resolution accuracy which is not conducive to practical application.Therefore,this paper mainly studied the integral scanning Talbot lithography,which can overcome the limited depth of focus,can realize the frequency muitiplication to increase the resolution.First of all,starting from the scalar diffraction theory,the physical mechanism of periodic array self-imaging based on the Talbot effect was introduced;On this basis,the theoretical model of integral scanning Talbot lithography was set up.Then,the simulation results by FFT method also show that this lithography technology can overcome the limited depth of focus and realize periodic multiplication,which prove the validity of the theoretical analysis.Furthermore,how the system factors including integral distance,starting position,non-uniform displacement velocity and different nature of lighting source influence the quality of obtained gratings are discussed in detail.Finally,the experimental preparation of the amplitude grating with periodic doubling frequency is studied by using the scanning integral Talbot lithography,which verifies the practical feasibility.As a result,the integral scanning Talbot Lithography can overcome the problem of finite focal depth,also can realize frequency doubling periodic array preparation,which proves that this technology is of great potential for periodic frequence-doubling in good contrast without any complex improvement and operation to the traditional proximity lithographic system of UV mask aligner.In addition,this paper explores the defect repair effect and its influencing factors of onedimensional periodic gratings and two-dimensional oblique periodic arrays with UV Talbot lithography by means of theoretical analysis and numerical simulation.The simulation results show that when the missing area is small and the missing elements are dispersed,the UV Talbot lithography combined with the high contrast photoresist can better recover the missing cells;When the missing area is large and concentrated,this lithography can not achieve the complete defect repair of the mask.Unfortunately,this paper does not quantitatively analyze the defect repair ability of talbot lithography.Therefore,the next step will be to find a suitable method for quantitative analysis of defect repair,as well as experimental study of high-contrast and high-sensitivity photoresist and related lithography parameters suitable for Talbot lithography.