Spectroscopic EUV metrology for nanoscale gratings

纳米级光栅的光谱 EUV 计量

• 批准号: 415848294
• 负责人: Professor Dr. Carlo Holly, since 7/2021
• 金额: --
• 依托单位: Lehrstuhl für Technologie optischer Systeme (TOS)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/415848294?language=en
• 关键词: Spectroscopic; EUV; metrology; nanoscale; gratings

Constantly decreasing feature sizes in semiconductor manufacturing lead to increasing demands on the metrology used in the production process. The metrology of nanoscale grating structures for the determination of the critical dimension is one of the core tasks.Since currently used spectroscopic metrology methods using infrared, visible and ultraviolet light are reaching their limits with respect to the sensitivity to very small feature sizes, alternative metrology methods are being explored. Especially metrology methods using X-rays have been extensively tested over the last years. However, these do not provide sufficiently small measuring spots and demonstrate only limited throughput. Metrology methods in the EUV spectral range, on the other hand, have the potential to overcome the mentioned disadvantages. The applicability of EUV metrology as a metrology method for nanoscale gratings should therefore be theoretically and experimentally investigated within the planned project.Spectroscopic EUV reflectometry at grazing angles of incidence will be used to identify contrasts in EUV reflectance of nanoscale gratings of different geometries (line width, trapezoidal angle). For this purpose, theoretical investigations will be carried out by means of rigorous electromagnetic diffraction simulations. After that, the simulation results will be used to extract spectral ranges and illumination settings for which particularly high contrasts between gratings of different geometries are expected. Based on these results, a set of samples with relevant geometry variations will be fabricated. Subsequently, the EUV reflectance of the fabricated samples will be determined experimentally in the applicant’s existing experimental setup for spectroscopic EUV reflectometry. In a further step, the grating geometry parameters will be reconstructed from the experimentally acquired EUV reflectance values by an iterative fit of simulated reflectance values to the experimentally measured ones. Conclusively, the theoretical limits of EUV metrology for nanoscale gratings will be evaluated, taking into account real measurement uncertainties, and including spectral ranges and illumination settings that are not directly accessible in the experiment. Finally, a comparison to the already existing metrology methods will be made with respect to the applicability to future feature sizes in semiconductor manufacturing.A successful outcome of the project will show that EUV metrology has the necessary sensitivity even for the smallest semiconductor feature sizes. EUV metrology can thus become an integral part of quality assurance and process control in future semiconductor manufacturing.

半导体制造中的特征大小不断减小，导致对生产过程中使用的计量学的需求不断增加。确定临界维度的纳米级光栅结构的计量学是核心任务之一。由于目前使用光谱计量学方法使用红外，可见光和紫外线光线达到了对非常小的特征大小的敏感性，因此正在探索替代的计量学方法。在过去的几年中，特别对使用X射线的计量方法进行了广泛的测试。但是，这些没有提供足够小的测量点，并且仅证明吞吐量有限。另一方面，EUV光谱范围内的计量方法具有克服上述缺点的潜力。因此，在计划的项目中，应在理论上和实验研究EUV计量学作为纳米级光栅的计量方法的适用性。光谱的EUV反射在发射率的振动角度将用于识别EUV的对比度的对比，以反射不同的纳米级反射（nansoscale genoseties的纳米级反射）（线条宽度宽度，宽度，Trapezoid terapezoid alytal）。为此，将通过严格的电磁衍射模拟进行理论研究。之后，模拟结果将用于提取光谱范围和照明设置，这些设置期望在不同几何的光栅之间特别高。基于这些结果，将制造一组具有相关几何变化的样品。随后，将在适用的光谱EUV反射率的现有实验设置中通过实验确定制造样品的EUV反射率。在进一步的一步中，将通过模拟反射值对实验测量值的迭代拟合，从实验获得的EUV反射率值中重建光栅几何参数。结论说，将考虑实际测量不确定性，包括在实验中无法直接访问的光谱范围和照明设置，包括纳米级光栅的EUV计量学的理论极限。最后，将与已经存在的计量方法进行比较，就半导体制造中未来功能大小的适用性进行比较。项目的成功结果将表明，即使对于最小的半导体特征大小，EUV计量学也具有必要的敏感性。因此，EUV计量学可以成为未来半导体制造中质量保证和过程控制的组成部分。