The advances on IC technology have made defect localization extremely challenging. “Soft” failures (resistive vias and contacts) are typically difficult to localize using commonly available failure analysis (FA) techniques such as emission microscopy (EMMI) and scanning optical microscopy (SOM), and often cannot be observed by two-dimensional inspections using layer by layer removal. The article describes the Resistive Contrast Imaging (RCI) defect localization technique (also known as Electron Beam Absorbed Current (EBAC), instrumentations, and case studies on test structures or process control monitors especially designed to detect “soft” open failures on advanced (28nm and below) technology devices. It also lists the key SEM parameters critical for effective FA using the RCI nano-probing system.

This paper presents two case studies, based on 32nm Silicon-On-Insulator (SOI) and 28nm bulk Si technology, on finding the root cause of nanometer scale short failures using Passive Voltage Contrast (PVC), Active Voltage Contrast (AVC) and Transmission Electron Microscopy (TEM). PVC/AVC is used as precision localization technique that is critical for a successful FA-TEM analysis. Combining planar TEM sample preparation and high sensitivity Energy Dispersive Spectroscopy (EDS) mapping, a small residual filament, which is not visible even at high resolution TEM, is found to short two metal lines. The effective usage of voltage contrast and TEM provides the need of high throughput, high precision, and high resolution in the advanced FA lab that serves leading-edge semiconductor manufacturing.