Paper
20 March 2020 OPO residuals reduction with imaging metrology color per layer mode
Shlomit Katz, Honggoo Lee, Dongyoung Lee, Jinsoo Kim, Jaesun Woo, Chunsoo Kang, Chanha Park, Dohwa Lee, Seongjae Lee, Sanghuck Jeon, Dongsub Choi, Anna Golotsvan, Roie Volkivich, Efi Megged
Author Affiliations +
Abstract
As the semiconductor industry rapidly approaches the 3nm lithography node, on product overlay (OPO) requirements have become tighter and as a result, residuals magnitude requirements have become even more challenging. Metrology performance enhancements are required to meet these demands. Color Per Layer (CPL) is a unique imaging overlay metrology approach that enables the measurement of each layer with individually-optimized wavelength and focus position. CPL allows the user to custom-define the most suitable conditions per layer, thereby ensuring optimal performance. Imaging-based overlay (IBO) utilizes CPL in order to overcome inaccuracies due to interactions between bottom and top layers. These layers are fundamentally different in that the top grating is usually the photoresist layer, but the bottom grating can be any process layer. Therefore, optimizing the conditions for each layer will maximize measurement accuracy. KLA’s Archer™ 700 metrology tool addresses these metrology challenges by putting CPL to use, where the Wave Tuner (WT) allows the user to select a specific wavelength. This paper presents this novel CPL approach and discusses its reduction in OPO and contrast, and reviews use cases from DRAM and 3D NAND. We will present the results from these case studies, focusing on SK Hynix DRAM production wafers.
© (2020) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Shlomit Katz, Honggoo Lee, Dongyoung Lee, Jinsoo Kim, Jaesun Woo, Chunsoo Kang, Chanha Park, Dohwa Lee, Seongjae Lee, Sanghuck Jeon, Dongsub Choi, Anna Golotsvan, Roie Volkivich, and Efi Megged "OPO residuals reduction with imaging metrology color per layer mode", Proc. SPIE 11325, Metrology, Inspection, and Process Control for Microlithography XXXIV, 113252E (20 March 2020); https://doi.org/10.1117/12.2541933
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CITATIONS
Cited by 2 scholarly publications.
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KEYWORDS
Metrology

Overlay metrology

Optical filters

3D metrology

Optical parametric oscillators

Semiconducting wafers

Near infrared

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