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提出了一种基于分离变量法的极紫外光刻三维掩模衍射谱快速仿真方法,在保证一定仿真精度的前提下提高了仿真速度。该方法将三维掩模分解为2个相互垂直的二维掩模,对2个二维掩模采用严格电磁场方法进行衍射谱仿真并将结果相乘以重构成三维衍射谱。以6°主入射角、45°线偏振光照明及22nm三维方形接触孔掩模为例,在入射光方位角0°~90°变化范围内,相同仿真参数下,该方法的仿真结果与商用光刻仿真软件Dr.LiTHO的严格仿真结果相比,图形特征尺寸误差小于0.21nm,仿真速度提高约65倍。在上述参数下,该方法与Dr.LiTHO的域分解方法及基于掩模结构分解法等快速方法相比,仿真精度和速度均提高1倍以上。该模型无需参数标定,适用于矩形图形的三维掩模快速仿真。
A rapid simulation method for the diffraction spectrum of EUV lithography three-dimensional mask based on the separation-variable method is proposed. The simulation speed is improved under the premise of ensuring a certain degree of simulation accuracy. In this method, the three-dimensional mask is decomposed into two perpendicular two-dimensional masks. The two two-dimensional masks are subjected to the diffraction spectrum simulation with a rigorous electromagnetic field method and the results are multiplied to reconstruct the three-dimensional diffraction spectrum. Taking the 6 ° main incident angle, 45 ° linear polarized light illumination and 22nm 3D square contact hole mask as an example, under the same simulation parameters, the simulation results of this method are similar to the commercial Compared with the rigorous simulation result of Dr.LiTHO, the feature size error is less than 0.21nm and the simulation speed is increased about 65 times. Under the above parameters, the accuracy and speed of simulation are more than doubled compared with the domain decomposition method of Dr. LiTHO and the rapid method based on mask structure decomposition. The model without parameter calibration, suitable for rectangular graphics rapid simulation of three-dimensional mask.