用于投射式电子束曝光系统的磁浸没透镜的优化设计

Optimization Design of Immersion Magnetic Lenses Used for Projection Electron Beam Lithography

以磁浸没透镜的电流密度值的大小为优化参量 ,以成像系统的轴上像散为目标函数 ,利用单纯形优化法对用于投射式电子束曝光系统的新型磁浸没透镜进行了优化设计。结果表明 ,目标函数由未经优化前的 35 8.187nm降低到 5 0 .6 93nm。同时单纯形优化法不需要已知目标函数与优化参量之间的解析关系式及求导 。

The design of a novel immersion magnetic lens,used in projection electron beam lithography,was optimized with the simplex method.In this method,the current density of the immersion magnetic lens was the key variable to be optimized and the axial astigmatism was taken as the objective function. The results show that the axial astigmatism decreased from 358.187 nm before the optimization to 50.693 nm after the optimization.Besides,the obvious advantage of the simplex method is that it is not necessary to know explicitly the analytical dependence of the objective function on the optimized variables.