Wordline defects in 3D Replacement Gate NAND (RG NAND) are a major issue holding back part functionality and yield. Shorted wordline locations isolated by EBIRCH enable precise lamella preparation for STEM/TEM, increasing the defect visual rate for physical failure analysis. Due to deprocessing limitations, such as specialized tool requirements, part-specific die preparation knowledge, and the location of the defect in the die, makes preparing samples for successful EBIRCH isolation difficult and time-consuming. A novel sample preparation method for SEM-based nanoprobing has been developed to solve these issues, enabling EBIRCH/EBAC for isolating wordline defect locations with minimal advanced deprocessing and which can be similarly applied to any RG NAND node.

In this paper, we present a new application of electron beam induced resistance change (EBIRCH) as a means to spatially isolate wordline shorts in 3D replacement gate NAND for high-precision physical failure analysis (PFA).