极紫外光辐照下表面碳沉积污染的计算模型

Simulation Model of Surface Carbon Deposition Contamination Under Extreme Ultraviolet Radiation

极紫外光刻（EUVL）是最有可能实现22 nm技术节点的下一代光刻技术。极紫外（EUV）光刻系统使用波长为13．5 nm，在此波段下曝光设备只能采用全反射式系统。然而，在极紫外光辐照下的光学元件，薄膜表层的碳化和氧化是导致EUV反射膜反射率下降的两种主要机制。结合EuV光学器件的表面分子动力学理论，研究碳沉积层的作用机理，以便找到抑制污染沉积的有效方法。通过针对碳污染层模型的计算研究，验证了模型和假设的有效性，从侧面证明了Boiler等的“二次电子诱导分解是主要沉积过程”理论。通过迭代法模拟了控制污染的几个关键参数对沉积层的影响，得到50～80 nm的非工作波段产生的碳沉积最为严重的计算结果。

Extreme ultraviolet lithography （EUVL） is one of the most promising candidates for next generationlithography to achieve 22 nm technology node. It takes of extreme ultraviolet （EUV） at 13. 5 nm. With thiswavelength, all the exposure equipments must be reflective. Whereas, for the extreme ultraviolet irradiated opticalelements, the two main mechanisms that reduce reflectivity of EUV reflective film are carbonization and oxidation ofthe film surface. Researching the mechanism of carbon deposited layer with surface molecule kinetic theory of EUVoptical devices to find an effective way for inhibiting the deposition of pollution. We investigate the validity of modelsand assumptions by researching on carbon pollution layer model, indirectly proving the Bollerrs theory ＂secondaryelectron induced decomposition is the main deposition process＂. Present preliminary numerical results on thedependence of contamination rates on key parameters with the iterative method, and suggest a band of 50-80 nmwhere will produce a higher contamination rate.