计算光刻是提高光刻成像性能的有效方法。但是, 大多数计算光刻技术建立在理想光刻系统下而忽略了系统误差的影响。系统误差中的工件台振动会导致光刻图形误差增大和工艺窗口下降。因此, 必须要降低工件台振动对光刻性能的影响。建立了一种对工件台振动低敏感的光刻系统协同优化方法。首先利用Zernike多项式表征光源来降低算法计算量并提高光源优化自由度。然后创建一项涵盖工件台振动影响的综合评价函数。最后采用基于梯度的统计优化算法建立优化流程。14 nm节点一维掩模图形仿真表明极端工件台振动下, 该方法的特征尺寸误差降低28.7%, 工艺窗口增大67.3%。结果证明该方法可以有效降低工件台振动敏感度并提高光刻工艺稳定性。

Computational lithography is an effective way to improve the lithographic imaging performance. However, most computational lithography technologies are usually established in an ideal lithography system without considering the impact of system errors. In fact, the stage vibration among the system errors can increase the lithographic pattern error and decrease the process window(PW). Therefore, it is imperative to reduce the impact of stage vibration on lithographic performance. For the first time to our knowledge, a lithography system holistic optimization method with low stage vibration sensitivity was proposed. Firstly, the source was represented by Zernike polynomials for easing the computational burden and improving the source flexibility. Then a weighted cost function incorporating the influence of stage vibration which consists of critical dimension error(CDE) and depth of focus(DOF) was built. Finally, a gradient-based statistical optimization algorithm was applied to build the optimization framework. The simulations of 1D mask pattern at 14 nm node show that for the system with extreme stage vibration, compared with the traditional method, the CDE of the proposed method is reduced by 28.7%, and the PW is increased by 67.3%. The results demonstrate that this method reduces the vibration sensitivity and improves the process robustness effectively.