为满足浸没式光刻照明系统对掩模面高均匀性和不同照明模式的要求，对照明系统中的照明模式变换器进行了研究。采用衍射光学元件(Diffractive Optical Elements，DOE)来产生各种照明模式，从光栅结构出发，经两步变换分析了光栅转变为DOE的过程。并提出一种离散抽样加密算法，以抽样线宽1~5 μm的四极照明DOE为例，揭示了DOE特征尺寸、衍射效率和光强分布非均匀性的实际对应关系。设计结果表明：随着抽样线宽的减小，整形光束的衍射效率和均匀性将得到较大提高。利用接触式光刻工艺完成了特征尺寸为1.76 μm×1.76 μm的16台阶照明模式变换DOE的制作，通过搭建光学测试平台对不同照明模式下DOE的光强非均匀性和衍射效率进行了测试，结果满足设计要求，验证了离散抽样加密算法能够有效指导照明模式变换系统DOE的设计。

In order to meet the high uniformity and different illumination mode requirement of the mask plane of the immersion lithography illumination system, the illumination mode converter system was studied. Diffractive Optical Elements (DOE) were used to generate various illumination modes, started from grating structure, the process of converting the grating into DOE by two-step transformation was analyzed. And a discrete sampling encryption algorithm was proposed. By examples of quadrupole illumination DOE with sampling width 1-5 μm, the correspondence relationship between the DOE feature size, diffraction efficiency and the intensity distribution non-uniformity was disclosed. The design results show that as the sampling line width decreases, the diffraction efficiency and uniformity of the shaped beam will be greatly improved. The 16-step illumination mode conversion DOE with feature size of 1.76 ?滋m×1.76 ?滋m was fabricated by contact lithography.The optical non-uniformity and diffraction efficiency of DOE under different illumination modes were tested by setting up an optical test platform. The results meet the design requirements and verify that the discrete sampling encryption algorithm can effectively guide the design of the DOE for the illumination mode transformation system.