极紫外光刻（Extreme ultraviolet lithography, EUVL）技术是7纳米以下节点集成电路芯片制造的首选光刻技术。由于EUV光易被空气吸收，EUV光刻机内部必须保持真空环境。在EUV光刻机曝光过程中，以光刻胶裂解、材料释气和高速微粒为主的污染物将导致光学器件表面污染和光刻质量降低。基于EUV光刻机的工况特点，可以将腔室真空环境分为考虑非曝光时的非工作真空与考虑曝光时的工作真空。面向EUV光刻机气体组分控制需求，本文以EUVL工件台腔室为研究对象，开展非工作真空下的简化建模与工作真空下的流态耦合建模，并基于两种模型分析了动态气体锁与低温冷板对EUVL工件台腔室气体组分控制的影响。 首先，面向分子流流态下的EUVL工件台腔室非工作真空建模需求，本文提出基于形状简化的最小包围面简化建模方法。在数值案例验证中，以微动台子系统为研究对象，分析比较了简化结构与原始结构的压强求解结果，并利用真空泵抽实验进一步验证该模型的准确性。结果表明，简化建模方案能够在取得小于6%仿真误差的同时，节省2/3以上的仿真时间。基于非工作真空模型开展EUVL工件台腔室的释气指标分解工作，确定了各子系统在满足腔室总压指标下的释气边界条件。 进一步，面向过渡流与滑移流共存的EUVL工件台腔室工作真空流场建模需求，结合直接仿真蒙特卡洛（DSMC）方法和Navier-Stokes（NS）方程在不同流态求解中的优缺点，本文采用基于状态参数传递的方案进行耦合建模。通过NS法和DSMC法的边界信息传递，完成流态耦合分区与计算。以EUVL工件台测试腔室为案例验证对象，数值计算与实验结果验证了该耦合建模方案的高效性与准确性。 最后，针对EUVL工件台腔室中的气体组分控制需求，本文在EUVL工件台腔室非工作真空简化建模与工作真空流态耦合建模的基础上，进行了动态气体锁与冷板的仿真分析工作。针对光刻胶裂解气体分压控制需求，基于工作真空流态耦合模型分析动态气体锁不同参数对EUVL工件台腔室光刻胶裂解气体分压的影响，得出清洁气体流量与污染气体分压的对数关系。针对水分压控制需求，利用低温吸附实验计算冷板对水分子的吸附系数，并基于非工作真空简化模型分析了冷板不同参数对EUVL工件台腔室水分压的影响。在优选参数方案中水分压下降高达83%，验证了低温冷板方案的可行性。
Extreme ultraviolet lithography (EUVL) technology is the preferred lithography technology for the manufacturing of integrated circuit below 7 nm features. Due to the strong absorption of EUV light by air, the EUVL machine must work in vacuum. During the exposure process of EUVL, contaminants such as outgassing of photoresist, outgassing of components, and particles at high speed will lead to surface contamination of optical elements and degradation of lithography quality. Based on the operating characteristics of EUVL machine, the environment in vacuum of the chamber can be divided into non-working vacuum when not exposed and working vacuum when exposed. Focusing on the requirements of gas composition control for EUVL machine, this thesis analyses the simplified modeling under non-working vacuum and the modeling of coupled flow field under working vacuum of the EUVL wafer stage chamber, and studies the influences of cold plate and dynamic gas lock on gas composition control in the EUVL wafer stage chamber based on the two models. Firstly, this thesis proposes a simplified modeling method based on shape simplification and minimum bounding surface for the requirements of vacuum modeling of EUVL wafer stage chamber in molecular flow. In the verification of numerical case, taking short-stroke subsystem as the research object, the pressure results of simplified structure and original structure are compared. The accuracy of simplified model is further verified by pumping experiments. The results show that the simplified modeling scheme can save more than two-thirds of simulation time while the simulation error is less than 6%. Finally, the outgassing targets of the EUVL wafer stage chamber are carried based on the simplified non-working vacuum model. Secondly, oriented to the requirements of modeling coupled flow field where transitional flow and slip flow are both existing in working vacuum of EUVL wafer stage chamber, a state-based coupling scheme is adopted to the modeling which combines the advantages and disadvantages of direct simulation Monte Carlo (DSMC) method and Navier-Stokes (NS) equation in different flow regimes. By transferring information between NS field and DSMC field, the pressure int the flow field can be simulated. Then the efficiency and accuracy of the coupled modeling scheme are verified by numerical calculation and experimental results by taking the testing EUVL wafer stage chamber as the case for verification. Subsequently, oriented to the requirements of gas composition control in EUVL wafer stage chamber, the simulation and analysis of dynamic gas lock and cold plate are carried out based on the simplified modeling in non-working vacuum and the coupled modeling in working vacuum of EUVL wafer stage chamber. To meet the requirements of photoresist outgassing control in EUVL wafer stage chamber, the relationship of different parameters of dynamic gas lock on the partial pressure of photoresist outgassing is analyzed based on the coupled model in working vacuum. Then, the adsorption coefficient of water molecules on the cold plate is calculated by carrying out a experiment at low temperature, and the impact of different parameters of cold plate on the pressure of water vapor in EUVL wafer stage chamber is analyzed based on the simplified model in non-working vacuum. In the optimal scheme, the pressure of water vapor is reduced by up to 83%, which demonstrates the feasibility of the cold plate scheme.
