菲涅尔衍射光刻

Fresnel diffraction lithography

通过合理选取等间距采样点的数目,利用快速傅里叶变换算法解释了有限通光光阑产生的“内密外疏”菲涅尔衍射条纹.基于菲涅尔衍射,在静态曝光、动态扫描条件下分别实现了约190 nm最小特征尺寸图形制备,以及约350 nm线宽线条直写.菲涅尔衍射光刻无需复杂的光学透镜组合,无需任何微纳衍射光学元件,且具有较大的聚焦容差.该方法有望成为一种新型的,低成本、高灵活度的亚波长图形制备手段.

Lithography plays a vital important role in modern information technologies.Patterning on a nanoscale in a handy way is highly desired for both scientific and industrial purposes.In this work,we propose a convenient nanolithography method based on Fresnel diffraction patterns.We start with the explanation of the "denseinside-sparse-out side" Fresnel diffraction fringes resulting from the apertures of finite extent,by using the fast Fourier transform algorithm through appropriately choosing the number of uniformly spaced samples.Moderately focusing the diffraction patterns via high-numerical-aperture objectives(the method is termed the "Fresnel diffraction lithography"),the rotationally symmetric patterns with a minimum feature size of ~190 nm,and the scanning lines with a width of ~350 nm are realized,respectively,The calculation using vectorial diffraction theory suggests a better resolution when perfectly focused.This method shows good tolerance to defocus and does not require complex lens combinations or micro/nano-diffraction optical elements,Therefore,this method can find some applications in widespread areas,e.g.functional metasurfaces,as a novel and lowcost nano-patterning technology with sub-wavelength resolution and high flexibility.