为有效评估和预测在极紫外光辐照下,极紫外光刻机中残留的碳氢化合物气体在多层膜光学元件表面造成的碳污染状况,建立了光学元件表面碳沉积的复杂理论模型,描述了残留碳氢化合物在光学表面的传输,在极紫外光子和二次电子激发下引起的分子分解,并在光学表面形成碳沉积层的过程。模型预测结果和实验数据吻合得很好。理论分析表明引起碳氢化合物分解的主要原因是光子分解而不是二次电子分解。碳层的增长依赖于碳氢化合物气体偏压和极紫外光强,具有较轻分子量的碳氢化合物(<~100amu)对污染的贡献很小。同时当基底温度适度增加时(~30℃),能够加速表面碳氢化合物分子的解吸附,可有效减少碳污染。 In order to effectively evaluate and predict the carbon pollution caused by the hydrocarbon gas remaining in the EUV lithography machine under the EUV light irradiation, a complex theoretical model of carbon deposition on the surface of the optical element is established. Describes the transport of residual hydrocarbons on the optical surface, the molecular decomposition caused by extreme ultraviolet and secondary electron excitation, and the formation of a carbon deposit on the optical surface. The model predictions and experimental data are in good agreement. Theoretical analysis shows that the main reason for the decomposition of hydrocarbons is photon decomposition rather than secondary electron decomposition. The growth of the carbon layer depends on the hydrocarbon gas bias and the intensity of the extreme ultraviolet light. Hydrocarbons with lighter molecular weights (<~ 100 amu) contribute little to the pollution. At the same time when the substrate temperature is moderately increased (~ 30 ℃), it can speed up the desorption of surface hydrocarbon molecules, which can effectively reduce carbon pollution.