针对应用于50~150 nm波段的变栅距光栅, 采用球面波曝光系统进行优化设计, 分析了不同宽度光栅的刻槽密度变化和光谱分辨能力。理论分析结果表明, 光栅宽度为4 mm时, 理论分辨能力高于14 000; 光栅宽度为10 mm时, 理论分辨能力约为9 000; 光栅宽度为30 mm时, 理论分辨能力急剧下降, 约为3 000。光栅的宽度越大, 其刻槽弯曲程度就越大, 光栅的光谱分辨能力就越低, 因此球面波曝光系统只适合制作宽度较小的变栅距光栅。

For the varied line-space (VLS) grating used in the region of 50-150 nm, the spherical wave exposure system was used for the optimization design, and the groove density and spectra resolution of the different width grating were analyzed. The theory resolution ability is higher than 14 000 when the grating width is 4 mm in the use of wavelength range, about 9 000 when the grating width is 10 mm, and about 3 000 when the grating width is 30 mm, respectively. The bigger the grating width is, the bigger the bending degree of groove is, and the lower the spectral resolution ability is. Therefore, spherical wave exposure system is only suitable for making the VLS grating with smaller width.