极紫外(EUV)投影光刻掩模在斜入射光照明条件下,掩模成像图形位置和成像图形特征尺寸(CD)都将随入射光方向变化,即存在掩模阴影效应。基于一个EUV掩模衍射简化模型实现了掩模阴影效应的理论分析和补偿,得到了掩模(物方)最佳焦面位置和掩模图形尺寸校正量的计算公式。掩模(物方)焦面位置位于多层膜等效面上减小了图形位置偏移;基于理论公式对掩模图形尺寸进行校正,以目标CD为22nm的线条图形为例,入射光方向变化时成像图形尺寸偏差小于0.3nm,但当目标CD继续减小时理论公式误差增大,需进一步考虑掩模斜入射时整个成像光瞳内的能量损失和补偿。 EUV projection lithography mask Under oblique incident illumination conditions, the position of the mask imaging pattern and the characteristic dimension (CD) of the imaging pattern will vary with the incident light direction, ie there is a shadow effect of the mask. Based on an EUV mask diffraction simplified model, the theoretical analysis and compensation of the mask shadow effect are realized. The formulas for calculating the optimal focal plane position of the mask (object side) and the size correction of the mask pattern are obtained. Mask (object) focal plane position is located on the equivalent surface of the multilayer film to reduce the position deviation of the pattern; based on the theoretical formula of the mask pattern size correction, the target CD 22nm line pattern as an example, the incident light direction The variation of the size of the image is less than 0.3nm. However, when the target CD continues to decrease, the error of the theoretical formula increases. Therefore, the energy loss and compensation of the entire imaging pupil when the mask is obliquely incident must be further considered.