电子束光刻研制高分辨X射线波带片透镜最新进展  

Recent Progress in Nanofabrication of High Resolution X-Ray Zone Plate Lenses by Electron Beam Lithography

作　　者：陈宜方 Chen Yifang(School of Information Science and Technology,Fudan University,Shanghai200433,China)

机构地区：[1]复旦大学信息科学与工程学院,上海200433

出　　处：《光学学报》2022年第11期74-88,共15页Acta Optica Sinica

基　　金：上海市科创仪器项目(STCSM2019-11-20,19142202700);自然科学基金联合基金(U1732104);国家重大科研仪器研制项目(61927820)。

摘　　要：首先综述了当前X射线透镜的分辨率和效率的水平,预测并讨论了发展我国波带片透镜、赶超国际先进水平的技术路径图。在原有100 nm分辨率波带片和会聚透镜工艺基础上,综述了电子束光刻结合金电镀进一步发展30~70 nm分辨率的X射线波带片的最新进展。在研发30 nm分辨率的波带片中,电子束光刻中的邻近效应严重限制了波带高宽比,而现有商业软件(基于蒙特卡罗模型和显影动力学)的邻近效应修正在同时处理从微米到30 nm的各种图形时效果甚微。为此,本团队针对70 nm分辨率的硬X射线波带片采用了图形修正法,实现了20:1的波带高宽比,针对50 nm分辨率的硬X射线波带片采用了分区域修正法,获得了15:1的波带高宽比;30 nm波带片透镜的金属化摒弃了传统的直流电镀工艺,采用脉冲金电镀,实现了金环均匀电沉积,成功研制了30 nm分辨率的软X射线波带片透镜和30~100 nm的大高宽比分辨率测试卡。所有研制的波带片透镜在上海同步辐射装置得到了X射线光学成像验证。This paper first reviews and comments on the performance of resolution and imaging efficiency of various types of X-ray lenses, and then discusses and predicts the roadmap of technical development of zone plate lenses in China, which was first established in 2013 by the author. Following the roadmap, the technical advance for the resolution from 70 nm up to 30 nm has been achieved by electron beam lithography with Au electroplating, based on the earlier success in 100 nm resolution zone plate lenses and convergent lenses for both soft and hard X-ray optics. When the resolution approaching 30 nm, the limitation to the aspect ratio(ratio of zone-height to zone-width) owing to the proximity effect in electron beam lithography becomes more and more severe. The commercial software packages, which are based on Monte Carlo model and development dynamics, are not able to manage the correction of proximity effect on the whole zone plate with the varying zone-widths from micrometers down to 30 nm. To overcome the difficulty, pattern correction of proximity effect is proposed in the electron beam lithography for 70 nm resolution zone plates and as high as 20:1 for the aspect ratio has been realized. Furthermore, a local proximity effect correction is also developed in replicating 50 nm resolution zone plates and the aspect ratio of 15:1 has been realized. In the attempt for 30 nm resolution zone plate lenses, pulsed Au electroplating is applied to eliminate the crystallization and epitaxial growth of Au, and 30 nm resolution zone plates for soft X ray are fabricated. For the characterizations of the fabricated zone plate lenses, high aspect ratio Siemens stars with various resolutions from 30 nm to 100 nm have been fabricated, which are used as standard samples for optical detection. 50 nm resolution imaging in both soft and hard X-ray has been demonstrated in Shanghai Synchrotron Radiation Facilities(SSRFs) for the first time in China by using completely in-house fabricated zone plate lenses.

关 键 词：X射线光学 X射线波带片透镜 X射线显微成像系统 电子束光刻纳米加工 30 nm分辨率 分区域/图形法邻近效应修正 脉冲金电镀工艺 

分 类 号：O436[机械工程—光学工程]