极紫外投影光刻物镜设计  

Design of Extreme Ultraviolet Lithographic Objectives

作　　者：杨雄[1] 邢廷文[1] 

机构地区：[1]中国科学院光电技术研究所,四川成都610209

出　　处：《光学学报》2009年第9期2520-2523,共4页Acta Optica Sinica

摘　　要：极紫外投影光刻用14 nm波长的电磁辐射,可以在实现高分辨率的同时保持相对较大的焦深,有希望成为制造超大规模集成电路的下一代光刻技术。极紫外投影光刻工作于步进扫描方式,采用全反射、无遮拦、缩小的环形视场投影系统。无遮拦投影系统的初始结构设计困难且重要。介绍了一种近轴搜索方法,该方法引入了像方远心、物方准远心、固定放大率、Petzval条件和物像共轭关系等约束,通过计算确定第一面反射镜、最后一面反射镜、光阑所在反射镜的曲率,以及物距和像距。编写了近轴搜索程序,搜索出初始结构。从初始结构出发,优化得到两套物镜,一套由四反射镜组成的系统,数值孔径0.1,像方视场26 mm×1 mm,畸变10 nm,分辨率优于6000 cycle/mm。一套系统由六反射镜组成,数值孔径0.25,像方视场26 mm×1 mm,畸变3 nm,分辨率优于18 000 cycle/mm。Using radiation with a wavelength of 14 nm, Extreme ultraviolet lithography （EUVL） can reach a high resolution and remain relative large depth of focus, and it is a promising future-generation lithographic technique for manufacturing VLSI. EUVL operates in step-and-scan mode, and utilize all-reflective unobstructed reduction ringfield projection system. The starting configurations designing of unobstructed projection system is a nontrivial and important issue. A paraxial search method is introduced, which imposes constraints, such as rigorous telecentricity on the image side, quasi-telecentricity on the object, fixed magnification, Petzval condition and conjugated objectimage. Curvatures of first mirror and last mirror, object distance and image distance are all solved consequently. And curvature of a reflecting surface coinciding with stop surface is solved. Paraxial search program is developed and some starting configurations are found. Two objectives are designed by optimizing two starting configurations. One is composed of four mirrors with the NA of 0.1, image field of 26 mm× 1 mm, distortion of 10 nm, and the resolution better than 6000 cycle/mm. The other objective is composed of six mirrors with the NA of 0.25, image field of 26 mm× 1 mm, distortion of 3 nm, and the resolution better than 18000 cycle/nm.

关 键 词：光学设计 物镜 光刻 极紫外 

分 类 号：O435.2[机械工程—光学工程]