High resolution nanotopography characterization at die scale of 28 nm FDSOI CMOS front-end CMP processes

• T-boxes are not representative of the die topography.
• Full die range is not the most representative die value.
• Full die and die σ ranges provide new and relevant data about die topography.
• Characterization of CMP impact of a structure on its neighborhood is made possible.
• Pattern density dependency of the CMP processes is quantifiable.

This work concerns high resolution topography characterization at die scale of 28 nm FDSOI CMOS technology by interferometric microscopy. It shows that usual test boxes (T-boxes) in scribe line are not representative of the full die topography. Consequently, new parameters are needed in order to take full advantage of high resolution topography characterization at die scale. In that sense, it is observed in this study that coupling full die and die σ ranges can provide new and relevant information about the Chemical Mechanical Polishing (CMP) processes. Moreover, high resolution die topography data makes possible to characterize in-die impact of a structure on its neighborhood and evaluate the pattern density dependency of the CMP processes.

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