大数值孔径产业化极紫外投影光刻物镜设计  

Design of High Numerical Aperture Projection Objective for Industrial Extreme Ultraviolet Lithography

作　　者：刘菲[1] 李艳秋[1] 

机构地区：[1]北京理工大学光电学院光电成像技术与系统教育部重点实验室(筹),北京100081

出　　处：《光学学报》2011年第2期224-230,共7页Acta Optica Sinica

基　　金：国家科技重大专项;教育部长江学者特聘教授奖励计划;北京理工大学基础研究基金(20090442019);北京理工大学优秀青年教师资助计划扩展项目(2010CX04020)资助课题

摘　　要：极紫外光刻技术（EUVL）是半导体制造实现22 nm及以下节点的下一代光刻技术,高分辨投影物镜的设计是实现高分辨光刻的关键技术。为设计满足22 nm产业化光刻机需求的极紫外光刻投影物镜,采用6枚高次非球面反射镜,像方数值孔径达到0.3,像方视场宽度达到1.5 mm。整个曝光视场内的平均波像差均方根值（RMS）为0.0228λ,不采用任何分辨率增强技术的情况下,75 nm光学成像的焦深内,25 nm分辨力的光学调制传递函数（MTF）大于45%。在部分相干因子为0.5-0.8的照明条件下,畸变小于1.6 nm,线宽变化小于1.6%。物面到像面的距离为1075 mm,像方工作距大于30 mm。该物镜结合离轴照明或相移掩模等分辨率增强技术,能够在更大的焦深内实现22 nm光刻分辨率的光刻胶成像,满足半导体制造中22 nm节点技术对产业化极紫外光刻物镜的需求。Extreme ultraviolet lithography （EUVL） is the next generation lithography for the semiconductor manufacturer to achieve 22 nm node and below. Design of the projection objective is a core technology for the high- resolution lithography. An optical projection system with six high-order aspheric mirrors is presented to meet the industrial needs of the extreme ultraviolet lithography at 22 nm node. In the catoptrics embodiment of the present design, an image numerical aperture of 0.3 and a field width of 1.5 mm are obtained resulting in a working resolution of 25 nm across the exposure field, while the depth of focus is greater than 75 nm and modulation transfer function （MTF） larger than 45 % without any resolution enhancement technologies. The mean wave front error of 0. 02282 （RMS） is reached. And the distortions of all field points are below 1.6 nm, CD （critical dimension） error is smaller than 1.6 % while it is partial coherently illuminated （partial coherent factor 0.5 - 0. 8）. The total length of the system is 1075 nm. Image working distance is above 30 mm. Combined with resolution enhancement technologies, such as off-axis illumination or phase-shift mask, a greater depth of focus for 22 nm resolution can be achieved within the photoresist to meet extreme ultraviolet lithography lens industry need with 22 nm nodes.

关 键 词：光学设计 投影物镜 高次非球面 极紫外光刻(EUVL) 

分 类 号：TN305.7[电子电信—物理电子学]