Mechanical stability analysis of 3D nanosheet-stacked structure

초록

The three-dimensionally (3D) stacked gate-all-around (GAA) nanosheet (NS) channel structures have been adopted into the state-of-the-art integrated circuit technologies to overcome the scaling limit of conventional device structure. However, a mechanical stress during the channel release process, which results in the channel deformation, is a severe concern for the high yield. In this study, the origins of the stress are examined by using a technology computer-aided design (TCAD) simulation and the design guidelines are proposed for the NS fabrication without the deformation. The results show that the stress is mainly determined by the active pads and NS length ratio (Lpad/LNS). Finally, it is demonstrated by fabricating the NS with Lpad/LNS = 1 that the mechanical stress is efficiently suppressed, thereby preventing the deformation.

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