| Autor: |
Philipp Hönicke, Grzegorz Gwalt, Anna Andrle, Philipp-Immanuel Schneider, Victor Soltwisch, Frank Siewert, Yves Kayser |
| Rok vydání: |
2021 |
| Předmět: |
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| Zdroj: |
Metrology, Inspection, and Process Control for Semiconductor Manufacturing XXXV. |
| DOI: |
10.1117/12.2586082 |
| Popis: |
The characterization of nanostructures and nanostructured surfaces with high sensitivity in the sub-nm range has gained enormously in importance for the development of the next generation of integrated electronic circuits. A reliable and non-destructive characterization of the material composition and dimensional parameters of nanostructures, including their uncertainties, is strongly required. Here, an optical technique based on grazing incidence X-ray fluorescence measurements is proposed. The reconstruction of a lamellar nanoscale grating made of Si3N4 is presented as an example. This technique uses the X-ray standing wave field, which arises due to interference between the incident and the reflected radiation, as nanoscale gauge. This enables the spatial distribution of the specific elements to be reconstructed using a finite-element method for the calculation of the standing wave field inside the material. For this, the optical constants for the constituent materials of the structure are needed. We derived them from soft X-ray reflectivity measurements on an unstructured part of the wafer sample. To counteract the expensive computation of the finite-element-Maxwell-solver, a Bayesian optimizer is exploited to obtain a most efficient sampling of the searched parameter space. The method is also used to determine the uncertainties of the reconstructed parameters. The homogeneity of the sample was also analyzed by evaluating several measurement spots across the grating area. For the validation of the reconstruction results, the grating line shape was measured by means of Atomic Force Microscopy. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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