采用一个极紫外投影光刻掩模衍射简化模型实现了三维接触孔掩模衍射场的快速仿真计算。基于该模型，得到了接触孔掩模衍射场分布的解析表达式，并对光刻成像时的图形位置偏移现象进行了解释和分析。简化模型中，掩模包括吸收层和多层膜两部分结构，吸收层的透射利用薄掩模修正模型进行计算，多层膜的反射近似为镜面反射。以周期44 nm、特征尺寸分别为16 nm和22 nm的方形接触孔为例，入射光方向发生变化时，该简化模型与严格仿真相比，图形特征尺寸误差小于0.4 nm，计算速度提高了近100倍。此外，考虑到多层膜镜面位置对图形位置偏移量的影响，得到了图形位置偏移量的计算公式，其计算结果也与严格仿真相一致。

This paper proposes a fast simulation method for the three-dimensional (3D) contact hole mask in extreme-ultraviolet lithography. Using the mask diffraction simplified model, an analytical expression of the diffraction spectrum of the contact hole is given, and theory analysis of the pattern shift effect is performed. The mask in the model includes two parts, the absorber and the multilayer structure. The absorber transmission is calculated using the modified thin mask model, and the multilayer reflection is approximated as mirror reflection. Taking 16 nm and 22 nm contact holes with a pitch of 44 nm as examples, the critical dimensional errors of the model are below 0.4 nm by comparison with the rigorous simulations, and the computation speed is increased nearly 100 times. Moreover, considering the equivalent location of the multilayer in the model, a formula is derived to calculate the amount of the pattern shift. The calculation results are consistent with those of the rigorous simulations as well.