光刻用准分子激光器光谱控制中温度分布对输出光谱影响特性分析

Analysis of Influence of Temperature Distribution in Spectral Control of Excimer Lasers for Lithography on Output Spectra

研究了激光传输过程线宽压窄模块内部热量累积对系统输出光谱的影响。通过理论分析及实验验证,分析了激光光束传输条件下,棱镜温度变化引起的材料折射率分布不均匀,以及不同惰性气体对输出激光光谱长时间稳定性的影响。结果表明,激光与线宽压窄模块内部元件相互作用,使光学元件温度升高,输出光谱展宽。惰性气体防护系统通过气体流动减小线宽压窄模块内部热量的积累,维持输出光谱的长时间稳定性。模块内部热量的累积对光谱纯度值影响较大,对半峰全宽影响不大。与N2相比,He折射率随温度变化较小,可使输出激光光谱纯度值长时间保持稳定。

To gain an in-depth understanding of the thermal effect of the excimer laser on the linewidth narrowing module(LNM),we investigated the influence of the internal heat accumulated in the module on the output spectrum of the system.Through theoretical analysis and experimental verification,we consider the uneven distribution of the refractive index caused by the temperature change of the prism and the influence of different inert gases on the longterm stability of the output laser spectrum.The results show that the laser interacts with the internal components in the LNM to increase the temperature of the optical components and broaden the output spectrum.The inert gas protection system reduces the accumulation of heat inside the LNM through gas flow and maintains the long-term stability of the output spectrum.The accumulation of heat inside the module has a great influence on the spectral purity value,and has little influence on the full width at half maximum.Compared with N2,the refractive index of He has a smaller change with temperature,which can keep the spectral purity of the output laser spectrum stable for a long time.