Presentation + Paper
27 April 2023 Soft x-ray: novel metrology for 3D profilometry and device pitch overlay
Christina Porter, Teis Coenen, Niels Geypen, Sandy Scholz, Loes van Rijswijk, Han-Kwang Nienhuys, Jeroen Ploegmakers, Johan Reinink, Hugo Cramer, Rik van Laarhoven, David O'Dwyer, Peter Smorenburg, Andrea Invernizzi, Ricarda Wohrwag, Hugo Jonquiere, Juliane Reinhardt, Omar el Gawhary, Simon Mathijssen, Peter Engblom, Heidi Chin, William T. Blanton, Sury Ganesan, Brian Krist, Florian Gstrein, Mark Phillips
Author Affiliations +
Abstract
Due to their increasingly complex 3D geometries, upcoming gate all around (GAA) devices pose new metrology challenges for which there is not yet any established HVM metrology solution, in particular for various critical timed etch steps [5]. Soft x-ray (SXR) scatterometry using 10-20 nm wavelength light is a promising next-generation metrology technique for 3D profile metrology and overlay (OVL) applications. This wavelength regime offers unique benefits over existing metrology techniques today: (1) Short wavelengths allow for higher resolution measurements than traditional visible wavelengths could offer, enabling measurement of structures at device pitches. (2) Primarily single scattering yields low correlation between parameters and aids physical interpretation of signals. This enables many parameters of interest to be extracted accurately and simultaneously. (3) SXR provides 3D capability, with stack heights up to 400 nm supported and high depth resolution due to the broadband source and sensor. These properties together make SXR suitable for measuring the 3D profiles of advanced devices such as gate all around (GAA) transistors, as well as after develop (ADI) overlay at device pitch. In this paper, we demonstrate SXR for profile metrology of GAA devices. We show sensitivity to average SiGe lateral recess etch depth as well as individual nanosheet critical dimensions, which cannot be reliably accessed by other nondestructive, inline metrology techniques available today. We furthermore demonstrate sensitivity in ADI OVL measurements directly on device-pitch structures in the presence of an underlying patterned nuisance layer.
Conference Presentation
© (2023) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Christina Porter, Teis Coenen, Niels Geypen, Sandy Scholz, Loes van Rijswijk, Han-Kwang Nienhuys, Jeroen Ploegmakers, Johan Reinink, Hugo Cramer, Rik van Laarhoven, David O'Dwyer, Peter Smorenburg, Andrea Invernizzi, Ricarda Wohrwag, Hugo Jonquiere, Juliane Reinhardt, Omar el Gawhary, Simon Mathijssen, Peter Engblom, Heidi Chin, William T. Blanton, Sury Ganesan, Brian Krist, Florian Gstrein, and Mark Phillips "Soft x-ray: novel metrology for 3D profilometry and device pitch overlay", Proc. SPIE 12496, Metrology, Inspection, and Process Control XXXVII, 124961I (27 April 2023); https://doi.org/10.1117/12.2658495
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KEYWORDS
Etching

Metrology

Overlay metrology

Diffraction

Signal detection

Semiconducting wafers

3D metrology

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