Terahertz near-field imaging of buried structures

We report a characterization of the spatial resolution of terahertz (THz) apertureless near-field imaging of metal lines deeply buried beneath a silicon dioxide layer. We find a good resolution for edge contrast, even in the case where the capping layer is considerably thicker than the tip radius. W...

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Veröffentlicht in:Optics express 2024-10, Vol.32 (22), p.39785
Hauptverfasser: Ma, Pingchuan, Kölbel, Johanna, Ying, Ji-Feng, Lin, J-H, Pizzuto, Angela, Mittleman, Daniel M
Format: Artikel
Sprache:eng
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Zusammenfassung:We report a characterization of the spatial resolution of terahertz (THz) apertureless near-field imaging of metal lines deeply buried beneath a silicon dioxide layer. We find a good resolution for edge contrast, even in the case where the capping layer is considerably thicker than the tip radius. We find that contrast and resolution depend on demodulation frequency, thickness of the capping layer, and radius of the tip. Furthermore, we observe a distinct dependence of the contrast on the direction of the incoming radiation, in both experiments and simulations. Characterization of buried features can be a valuable tool in non-contact failure analysis of semiconductor devices.
ISSN:1094-4087
1094-4087
DOI:10.1364/OE.532478