支撑应力对光刻透镜透射波前畸变的影响

为了设计光刻物镜的支撑结构,建立了支撑应力对透镜透射波前影响的模型,研究了该模型中支撑应力与折射率的关系及支撑应力对透镜透射波前畸变的影响。首先,根据晶体理论,建立了融石英透镜波前畸变与支撑应力之间关系的仿真模型。然后,分析了不同支撑结构下支撑应力与融石英透镜波前的关系。最后,分析了支撑应力造成的透射波前畸变的性质,并选择合适的物镜支撑结构。研究结果表明：光刻物镜支撑结构的支撑应力对透镜的透射波前有很大的影响：3点支撑的波前畸变PV值为3.69 nm;随着支撑点数量的增加,支撑应力造成的透射波前畸变逐渐减少;采用大于9点的支撑结构即可满足光刻投影物镜的元件支撑需求。

Influence of mounting stress on wavefront distortion of lithographic object lens

To design the mounting structure of a lithographic object lens, the influence model of mounting stress on the lens wavefront distortion was built. The relation between mounting stress and refractivity and the influence of mounting stress on the wavefront distortion of the lens were studied. First, based on the crystal theory, the relationship of lens mounting stress and wavefront distortion of a fused silica lens was established. Then, the influence of different lens mounting structures on the lens wavefront distortion was analyzed. Finally, the properties of lens mounting wavefront distortion were researched, and the fitted lens mounting structure was selected. Analysis results indicate that the lens mounting stress has a great influence on the lens wavefront distortion. The wavefront distortion of a 3-point mounting structure is 3.69 nm. However, the wavefront distortion induced by mounting stress decreases with the increasing mounting points. The above 9-point mounting structure is fitted to the lithographic object lens.