Utilizing PFIB for Preparing TEM Lamellae Tailored to High Aspect Ratio 3D NAND Structures

Abstract The TEM sample preparation by Plasma focused ion beam (PFIB) for a 3D NAND sample with high aspect ratio (HAR) was investigated. Through the PFIB window delayering method, a nearly curtain-free and uniform thickness of TEM lamella could be obtained, addressing the issue of curtaining effectively. Moreover, the pre-treatment step for preparing the chunk of the region of interesting (ROI) out from wafer can be performed by PFIB automated procedures, which could promote the sample preparation efficiency. Through the PFIB window delayering method, TEM analysis of large-area HAR 3D NAND nanostructures becomes achievable.