A breakthrough on throughput and accuracy limitation in ellipsometry using self-interference holographic analysis

Jaehwang Jung; Yasuhiro Hidaka; Jinseob Kim; Mitsunori Numata; Wookrae Kim; Shinji Ueyama; Myungjun Lee

doi:10.1117/12.2581555

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15 March 2021 A breakthrough on throughput and accuracy limitation in ellipsometry using self-interference holographic analysis

Jaehwang Jung, Yasuhiro Hidaka, Jinseob Kim, Mitsunori Numata, Wookrae Kim, Shinji Ueyama, Myungjun Lee

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Proceedings Volume 11611, Metrology, Inspection, and Process Control for Semiconductor Manufacturing XXXV; 116111J (2021) https://doi.org/10.1117/12.2581555
Event: SPIE Advanced Lithography, 2021, Online Only

Abstract

An innovative self-interferometric pupil ellipsometry (SIPE) technique has been demonstrated to overcome the accuracy and throughput limitations raised from the conventional spectroscopic ellipsometry (SE) tools to precisely measure the optical critical dimensions (OCD) in the advanced semiconductor devices. The proposed SIPE technique will be extremely powerful, because key ellipsometric parameters, Ψ and Δ, from all possible incident angles can be obtained simultaneously from the single measurement, while the conventional SE technique needs to collect several hundreds of measurements to get the identical information. By employing a Nomarski prism, one can angularly separate the reflected light from the wafer into two orthogonally polarized lights. Then, the self-interference pupil ellipsometer could interfere those two beams without an additional reference beam path. The interfered fringe includes rich ellipsometric information at incident angles from -70º to 70º with 0-360º azimuthal directions, where those Ψ and Δ information can be extracted by the novel holographic algorithm we proposed. To verify the usefulness of SIPE system and the algorithms, both experimental and theoretical validation have been performed for the patterned wafers. In short, the proposed system and algorithms, which are completely new concept, show a capability to overcome current metrology challenges by breaking multiple parameter correlations between various structural parameters, eventually resulting in the improved metrology sensitivity and precision. Based on the results presented here, we strongly believe the SIPE is a promising metrology solution that can be eventually replacing the traditional OCD tools.

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Jaehwang Jung, Yasuhiro Hidaka, Jinseob Kim, Mitsunori Numata, Wookrae Kim, Shinji Ueyama, and Myungjun Lee "A breakthrough on throughput and accuracy limitation in ellipsometry using self-interference holographic analysis", Proc. SPIE 11611, Metrology, Inspection, and Process Control for Semiconductor Manufacturing XXXV, 116111J (15 March 2021); https://doi.org/10.1117/12.2581555

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