为了提升扫描干涉场曝光光束对准精度，保证制作的光栅掩模槽形的质量，建立了曝光光束对准误差模型，利用模型对光束对准误差进行了分析。同时为了满足系统对光束重叠精度的要求，设计研制了光束自动对准系统，并对曝光光束进行了对准实验。分析结果表明，当光束存在较大对准误差时，光栅基底表面曝光对比度大幅下降，而且由于采用步进扫描的曝光方式，光刻胶表面出现了各处曝光不均匀的现象，影响光栅掩模槽形的质量。设计的对准系统可以对光束角度与位置进行对准调节，系统整体表现出良好的收敛性能，多步调节后可使光束位置对准精度优于10 μm，光束角度对准精度优于9 μrad。这样的曝光光束对准精度可以满足系统要求，达到了预期的设计目的。

In order to improve alignment accuracy of exposure beams in the scanning beam interference lithography system and guarantee quality of the fabricated grating mask groove shape, an alignment error model of exposure beams is established and used to analyze the beam alignment error. Meanwhile, to meet the requirement of the system for beam overlapping accuracy, an automatic beam alignment system is designed and fabricated, and alignment experiments are conducted on the exposure beams. Analysis results show that the exposure contrast on the grating substrate surface decreases obviously when the beams have large alignment errors. Under the exposure mode of stepping-scanning, uneven exposure appears at different positions of the photoresist surface, which influencing the quality of grating mask groove shape. The designed alignment system can adjust the beam angles and positions. The system shows good convergence performance as a whole. After multi-step adjustment, the position alignment accuracy of the beams exceeds 10 μm, and the angle alignment accuracy of the beams exceeds 9 μrad. The alignment accuracy of exposure beams satisfies system requirements and the expected purpose is achieved.