Marangoni Effect-Based Under-Layer For A Dual Damascene Via-First Approach

A scalable solution to the unwanted photoresist swing effect.


One of the main challenges of a Dual Damascene (DD) via-first process is the control of the Critical Dimensions (CDs) in the lithography of the trenches. The PhotoResist (PhR) thickness presents variations from the via arrays to the open areas, which cause the variation of CDs: the swing effect. The planarization of a DD via-first process is reported. A dual-layer solution is used to demonstrate the complete filling of deeply etched structures and the advanced planarization in a multilayer technique. The first material coating the substrate exhibits a Marangoni effect; the second material owns the same physico-chemical properties of the first one, except for the Marangoni properties.

The Marangoni effect of the first coating produces a thicker film in the via array than in the open area, resulting in a negative Film Thickness (FT) bias. Then, the coating with second material is performed and having it standard planarization properties, a positive thickness bias occurs. The addition of these two coatings results in a thickness bias intra-die and on complex topographies, ranging from 0 nm to 30 nm across the wafer.

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STMicroelectronics (Italy): V. Dall’Asta, E. Litterio, N. Corneo, P. Cantù
Brewer Science: J. Koza, J. Jeauneau

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V. Dall’Asta, E. Litterio, N. Corneo, J. Koza, J. Jeauneau, and P. Cantù “Marangoni effect-based under-layer for a Dual Damascene via-first approach: a scalable solution to the unwanted photoresist swing effect”, Proc. SPIE 11326, Advances in Patterning Materials and Processes XXXVII, 1132622 (23 March 2020);

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