Dresden 2017 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 21: Thin Film Characterisation: Structure Analysis and Composition II

DS 21.4: Vortrag

Dienstag, 21. März 2017, 10:15–10:30, CHE 91

Characteristic Diffuse Scattering from Rough Lamellar Gratings — •Analia Fernandez Herrero¹, Victor Soltwisch¹, Mika Pflüger¹, Jürgen Probst², and Frank Scholze¹ — ¹Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany — ²Helmholtz-Zentrum-Berlin (HZB), Albert-Einstein Str. 15, 12489 Berlin, Germany

Lamellar-gratings are commonly-used diffractive optical elements or structural elements in state-of-the-art integrated electronic circuits. For the control of the lithographic manufacturing process a rapid in-line characterization of such structures is indespensible. There are numerous reports on the determination of the geometry parameters of such gratings from optical and EUV light scattering. With shrinking structure sizes, roughness gains influence on the structure performance. Its characterization by scatterometry requires to identify the roughness contributions. For lamellar gratings, roughness is clasified as line width roughness (LWR) or line edge roughness (LER). We prepared a set of eight Si-lamellar gratings with well defined LER or LWR and a prototype grating by e-beam lithography at HZB. The samples were investigated at PTB using EUV-scatterometry, which is very sensitive to the imperfections on the structures and therefore provides a high sensitivity for roughness. We observed that each type of line roughness leads to a characteristic diffuse scattering pattern, with strong correlation between the type of roughness and the diffuse scatter angular distribution. The analysis of these diffuse scatter contributions opens a new path for the roughness characterization of line structures.