The continuous growth and advancements of semiconductor devices for automotive applications and internet-of-things drive the demand and scaling of embedded non-volatile memories (eNVM). Existing eNVM landscape in 40 nm and 28 nm advanced processes is dominated by split-gate flash memory devices (Do, 2016) where inter-poly oxide (IPO) defect is one of the most challenging types of defect to localize (Tan et al., 2019). IPO defects typically surface as full or partial row NVM failures due to globally shared polysilicon select gate, control gate or erase gate among thousands of NVM cells. Conventional NVM bitmap is not effective to isolate these failures. In this paper, a systematic 2 steps isolation approach using nanoprobing techniques is proposed to effectively localize IPO defects. The first step involves the inter-poly leakage characterization to isolate the smallest failure sub-block. The next step utilizes Electron Beam Absorbed Current (EBAC) analysis to effectively localize IPO defect in nanoscale resolution subsequent TEM analysis. Two case studies of split-gate automotive grade eNVM suffering from read/write cycling failure were described to demonstrate the usefulness of the proposed techniques for accurate and precise localization on the NVM IPO defect.

用于汽车应用和物联网的半导体器件的不断增长和发展，推动了嵌入式非易失性存储器（eNVM）的需求和规模扩展。在40 nm和28 nm先进工艺中，现有的eNVM格局主要由分栅闪存器件（Do，2016）主导，其中多晶硅氧化物（IPO）缺陷是定位缺陷中最具挑战性的缺陷类型之一（Tan等。 ，2019）。IPO缺陷通常由于成千上万个NVM单元之间共享的多晶硅选择栅，控制栅或擦除栅而表面上全部或部分出现行NVM故障。传统的NVM位图无法有效隔离这些故障。在本文中，提出了一种使用纳米探测技术的系统的两步隔离方法，以有效地定位IPO缺陷。第一步涉及多晶间泄漏表征，以隔离最小的故障子块。下一步利用电子束吸收电流（EBAC）分析来有效地定位IPO缺陷，并随后进行TEM分析。描述了遭受读/写循环故障的裂口汽车级eNVM的两个案例研究，以证明所提出的技术对NVM IPO缺陷进行精确定位的有用性。