Wang Nan, Li Yi, Sha Feng, He Yu
Opt Lett. 2022 Sep 1;47(17):4427-4430. doi: 10.1364/OL.468177.
Lithography for the next generation of integrated-circuit manufacturing at the 3 nm node requires sub-1-nm misalignment measurement accuracy, which is almost impossible for existing systems due to the optical diffraction limit. Herein, we propose a misalignment sensing strategy based on structured illumination. By virtue of the distinctive modulation effect of a Talbot diffractive illuminated field on moiré fringes, the measurement signals can pass unhindered through the optical system and be used for sensing. Experiments are used to demonstrate that the proposed method can implement real-time-lapse (100 Hz) misalignment sensing with an accuracy of sub-1-nm (0.31 nm @ 3σ), making it suitable for various lithography techniques (e.g., proximity, x ray, projective, and nanoimprint lithography) and fields requiring advanced precision measurement (e.g., quantum measurement, gravitational wave detection, and molecular biology).
用于3纳米节点下一代集成电路制造的光刻技术需要亚1纳米的对准测量精度，由于光学衍射极限，现有系统几乎无法实现这一精度。在此，我们提出一种基于结构照明的对准传感策略。借助于塔尔博特衍射照明场对莫尔条纹的独特调制效应，测量信号可以不受阻碍地通过光学系统并用于传感。实验表明，该方法能够以亚1纳米（3σ时为0.31纳米）的精度实现实时（100赫兹）对准传感，适用于各种光刻技术（如接近式、X射线、投影式和纳米压印光刻）以及需要高精度测量的领域（如量子测量、引力波探测和分子生物学）。
