Combination of optics-based and SEM-based techniques for fault isolation of advanced technology node devices

Failure analysis is essential for semiconductor technology development, manufacturing yield improvement, and long-term product reliability. As device dimensions continue to shrink into the single-digit nanometer regime, traditional optics-based global fault isolation (GFI) techniques—such as lock-in thermography, photon emission microscopy, optical beam-induced resistance change, thermally induced voltage alteration, critical parameter analysis, and laser voltage imaging/probing—are increasingly limited by the diffraction limit of light and can no longer precisely localize defects in dense 3D structures, including FinFETs and gate-all-around (GAA) nanosheet devices. Consequently, semiconductor failure analysis now relies heavily on SEM-based local fault isolation techniques, including nanoprobing, active voltage contrast, electron beam absorption current, electron beam induced current, and electron beam induced resistance change, which offer true nanoscale spatial resolution. However, these SEM-based techniques are only suitable to investigate a small area, which need be priorly narrowed down by GFI. This article evaluates the strengths and limitations of both optics-based and SEM-based techniques and presents case studies showing how combining these complementary techniques enables faster, more efficient, and more accurate defect localization in advanced 2 nm GAA nanosheet devices.