From Event: SPIE Advanced Lithography + Patterning, 2023
An innovative metrology technique has been devised to address current limitations of optical critical dimension (OCD) in advanced semiconductor metrology. This technique is based on multiple self-interferometric pupil imaging, called Mueller matrix self-interferometric pupil ellipsometry (M-SIPE). The system integrates an innovatively designed interference generator in both illuminating and imaging optics, allowing for the massive acquisition of full polarization information across entire angles around the device. The vast amount of information can offer fully comprehensive structural analysis, accomplishing enhanced sensitivity and the ability to break the well-known parameter correlation issues. The system employs a single-shot holographic measurement technique on the pupil plane, enabling rapid acquisition of three-dimensional spectral information, such as wavelengths, incidence angles, and azimuth angles. Thus, unlike conventional OCD tools, M-SIPE can obtain multi-angular and full polarization information without any mechanical movements. We verified the performance of M-SIPE by the experiment of non-patterned wafers of various conditions using an optical testbed. Our results confirmed good agreement between the experiment and theoretical simulations across all angular ranges. Furthermore, the actual device simulation was conducted to show sensitivity enhancement and ability for breaking the parameter correlation issues. The results confirmed that the large amount of angular information from M-SIPE technique could overcome current metrological challenges.
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Garam Choi, Jinyong Kim, Daehoon Han, Young-Uk Jin, Soonhong Hwang, Jinseob Kim, Wookrae Kim, Jaehwang Jung, Seungwoo Lee, Taejoong Kim, Jinwoo Ahn, Myungjun Lee, Gideok Kim, Su-Young Lee, and Yusin Yang, "Mueller matrix metrology with multi-angle information using multiple self-interference," Proc. SPIE 12496, Metrology, Inspection, and Process Control XXXVII, 1249610 (Presented at SPIE Advanced Lithography + Patterning: March 01, 2023; Published: 27 April 2023); https://doi.org/10.1117/12.2657852.