为实现λ/100峰谷值(PV)的光刻投影物镜面形检测精度要求，深入分析了自重变形对大口径超高精度Fizeau干涉仪的光学性能产生的影响。设计的球面标准具结构，其系统波像差达到λ/1000(PV)、像方数值孔径（NA）值为0.36，用于口径超过300 mm的球面镜面形检测。使用Patran/Nastran软件通过有限元方法（FEM）对标准具镜组中一块镜子在胶结辅助支撑和压圈切向支撑两种支撑方式下的自重变形进行分析的基础上，得出在假定载荷作用下各光学元件表面的变形量及刚体位移量。利用泽尼克多项式将变形量大小进行拟合，得到镜子的波像差大小，完成光机转换，分析得到适合的支撑方式。将此支撑方式运用到整个系统，实现了在自重变形下系统的波像差大小优于λ/100(PV)水平。结果证明采用这种支撑方式，可以满足超高精度检测要求，为合理的干涉仪设计提供了数据依据、为提高系统精度奠定了基础。

In order to realize the figure accuracy of λ/100 peak-vally (PV) value for the lithographic projection objective, the effect of gravity deformation on the optical performance of large-aperture Fizeau interferometer with super accuracy has been deeply analyzed. The optical configuration designed with a wavefront aberration of λ/1000(PV) and a numerical aperture(NA) of 0.36 in image space are employed to test the spherical surface with a diameter larger than 300 mm. One element in the configuration is analyzed by the finite element method (FEM) under two supporting types: adhesive support and retainer support. Based on the finite element analysis(FEA) results, surface deformation and body displacement due to gravity are obtained under a certain condition of load. By Zernike polynomials, the surface deformation is fitted, the wavefront error is acquired, the optomechanical conversion is finished, and a proper supporting type is proposed. When this supporting type is applied to the whole configuration, the wavefront aberration of the system achieved is better than λ/100 (PV). The result verifies that super accuracy can be reached. Besides, the data offered here will be useful for a reasonable interferometer design.