大数值孔径极紫外光刻物镜设计

Design of High Numerical Aperture for Extreme Ultraviolet Lithography Objective Lens

设计了一种大数值孔径、高分辨率的环形视场极紫外光刻物镜。以环形视场两镜系统的设计理论为基础,推导了相关参数的计算公式;并由此推广到六反射镜系统。该系统采用六枚非球面反射镜,利用环形视场避开普通反射系统的中心遮拦,并通过对分辨率的计算,实现了NA=0.3的大数值孔径。各视场的残余波像差的均方根半径RMS均小于0.02λ,相对畸变小于1%,在线视场220 mm处的传递函数达到衍射极限,可实现22 nm及以下节点的光刻技术。

A large numerical aperture, high-resolution circular field of view EUVL objective lens is designed. It is based on a circular field of view mirror system design theory, derive the formula of relevant parameters, and thus extended to the six-mirror system. The system uses six aspheric mirrors, and an annular field of view to avoid the central obscuration of the ordinary reflection system. Throuth the calculated of resolution, to achieve a large numeri- cal aperture of NA = 0. 3, and the RMS of every field less than 0. 02A , the relative distortion less than 1% , the transfer function of 220 mm at diffraction limit. This system can achieve the photolithography technique below 22 nm node.