大面积10000线/毫米软X射线金属型透射光栅的设计、制作与检测

基于严格的矢量耦合波理论，优化设计了用于13.4nm软X射线干涉光刻的透射型双光栅掩模版. 采用电子束光刻技术，在国内首次成功制作了周期为100nm的大面积金属型透射光栅.光栅面积为1.5mm ×1.5mm，Cr浮雕厚度为50nm，Gap/period为0.6，衬底Si₃N₄厚度为100nm. 此光栅将用于上海光源软X射线干涉光刻实验站.利用其1级衍射光和2级衍射光将可以经济高效地制作周期为50和25nm的大面积周期结构.最后，测量了该光栅对波长为13.4nm 同步辐射光的衍射光强度，并且推算得出该光栅的1级和2级衍射效率分别为4.41%和0.49%，与理论设计值比较符合.实验结果与理论模拟结果的对比表明该光栅侧壁陡直，Gap/period的控制也与设计值符合. 关键词： 软X射线金属型透射光栅 严格耦合波方法 衍射效率 软X射线干涉光刻

The design, fabrication and performance of a large area 10000 line/mm metal transmission diffraction gratings for soft X-ray

Based on the rigorous coupled-wave analysis, the optimized design for a transmission two-gratings mask for 13.4nm soft X-ray interference lithography has been accomplished. Then a large area transmission gratings was successfully fabricated by electron beam lithography (EBL), which has an area of 1.5mm×1.5mm, ruling period of 100nm, Cr relief thickness of 50nm, gap/period of 0.6, and Si₃N₄ substrate thickness of 100nm. Based on the quantitative estimation of the measurement data, the first and second order diffraction efficiencies were determined as 4.41% and 0.49%, respectively， in good agreement with the numerical simulation results. Through comparison between the measurement and the numerical simulation results, it was shown that the relief is entirely vertical and the gap/period was well controlled. This two-grating mask will be used installed on the soft X-ray interference lithography endstation at Shanghai Synchrotron Radiation Facility (SSRF). With its 1st and 2nd order diffraction, 50nm period and 25nm period gratings can be cost-effectively fabricated, respectively.