Hao Ming, Teng Shuai, Liu Jiaxing, Xie Yuanhua, Ba Dechun, Bian Xin, Ba Yaoshuai, Chen Zhengwei, Liu Kun
School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China.
Tobacco Machinery Co., Ltd., Qinhuangdao, China.
J Chem Phys. 2024 Jan 28;160(4). doi: 10.1063/5.0182717.
The optical surface of extreme ultraviolet (EUV) lithography machines is highly vulnerable to contamination by hydrocarbons, resulting in the formation of carbon deposits that significantly degrade the quality and efficiency of lithography. The dynamic gas lock (DGL) has been proven as an effective approach to alleviate carbon deposition. However, the majority of existing studies on carbon deposition neglect the influence of the DGL. This paper is dedicated to investigating the phenomena of hydrocarbon adsorption, desorption, and cleavage with considering the effects of the DGL. A comprehensive mathematical model of the carbon deposition process is established, and the impact of radiation intensity, temperature, and hydrocarbon types on the depositing rate is considered. The results suggest that the primary cause of carbon deposition is the direct cracking of hydrocarbons induced by photons with a wavelength range between 12.5 and 14.5 nm. Additionally, it has been observed that the carbon deposition rate decreases exponentially as clean gas flow increases when EUV radiation intensity exceeds 50 mW/mm2. Conversely, at low EUV radiation intensity, clean gas flow has little effect on the carbon deposition rate. An effective approach to mitigate carbon deposition is to elevate the temperature of the optical surface and employ light hydrocarbon materials in the EUV process.
极紫外（EUV）光刻机的光学表面极易受到碳氢化合物污染，导致形成碳沉积物，从而显著降低光刻的质量和效率。动态气锁（DGL）已被证明是减轻碳沉积的有效方法。然而，现有的大多数关于碳沉积的研究都忽略了DGL的影响。本文致力于研究考虑DGL影响的碳氢化合物吸附、解吸和裂解现象。建立了碳沉积过程的综合数学模型，并考虑了辐射强度、温度和碳氢化合物类型对沉积速率的影响。结果表明，碳沉积的主要原因是波长范围在12.5至14.5 nm之间的光子引起的碳氢化合物直接裂解。此外，还观察到当EUV辐射强度超过50 mW/mm2时，随着清洁气体流量增加，碳沉积速率呈指数下降。相反，在低EUV辐射强度下，清洁气体流量对碳沉积速率影响很小。减轻碳沉积的有效方法是提高光学表面的温度，并在EUV工艺中使用轻质碳氢化合物材料。
