Four-dimensional scanning transmission electron microscopy (4D-STEM) is a spatially resolved electron diffraction technique that records the electron scattering distribution at each point of the electron beam raster, thereby producing a four-dimensional dataset. The final article in this series covers ptychography, a form of computational imaging that recovers the phase information imparted to an electron beam as it interacts with a specimen.

Soft electrical failures caused by monograin defects can have a significant impact on yield in technology nodes below 40 nm. Moreover, the failures are hard to identify and the defects give very few signatures during localization testing. In this article, the authors explain how they used nanobeam diffraction with automated crystal orientation and phase mapping to pinpoint a single grain orientation causing the problem and, as a result, are now able to recognize the symptoms of this type of failure, observe the defect, and limit the impact on electrical timing margins through both design and process corrections.

This column explains how simulation tools and materials life data can provide a new level of productivity for engineers involved in forensic analysis of MEMS devices.

This article discusses the basic principles of terahertz time-domain spectroscopy (THz-TDS) and the function and limitations of key components in a THz-TDS system. It also provides examples of some of the ways THz-TD imaging is used alone and in combination with other analytical techniques.

The second Electronics Resurgence Initiative (ERI 2.0), sponsored by the U.S. Defense Advanced Research Project Agency (DARPA) Microsystems Technology Office (MTO), is focused on driving next generation dual use microelectronics for national security and domestic needs. The initiative focuses on creating U.S. capability for three-dimensional heterogeneous integration (3DHI) manufacturing and pursuing focused research for the manufacture of complex 3D microsystems. This guest editorial describes the outcomes from a three-day summit (Seattle, Washington, August 2023) where the initiative was launched.

Root-cause analysis and FA work hand-in-hand to identify the source of a problem, gather relevant data, and resolve the issue. However, even experienced professionals can succeed in FA while failing in the outcome. This article explains how to avoid common traps, dead ends, and faulty thought processes in the search for root causes.

Long-term stability studies indicate that cathode degradation is one of the main failure mechanisms in anode-supported SOFCs. In order to better understand the microstructural degradation mechanisms of the cathode and the influence of oxygen partial pressure at relevant operating temperatures, the authors of this article acquired TEM samples from technological cells to study cation interdiffusion mechanisms and LSM-YSZ interactions, particularly in areas where LSM grains are in contact with YSZ electrolyte. Here they present and interpret the results.

This article describes a form of lock-in thermography that achieves 3D localization of thermally active defects in stacked die packages. In this approach, phase shifts associated with thermal propagation delay are analyzed as a function of frequency. This allows for a precise localization of defects in all three spatial dimensions and can serve as a guide for subsequent high-resolution physical analyses.

A scanning electron microscope system measures voltage contrast on device-under-test surfaces. This article addresses a limited set of applications that rely on voltage contrast (VC) measurements in SEM systems, showing how VC measurements can probe electrical activity running at speeds as high as 2 GHz on modern active integrated circuits.

Modified Talbot X-ray interferometry provides three contrast modes simultaneously: absorption, phase, and dark field/scattering. This article describes the powerful new imaging technique and shows how it is used to characterize various types of defects in advanced semiconductor packages.

Four-dimensional scanning transmission electron microscopy (4D-STEM) is a spatially resolved electron diffraction technique that records the electron scattering distribution at each point of the electron beam raster, thereby producing a four-dimensional dataset. This second installment of this series presents applications of 4D-STEM, including measurements of crystal orientation and phase, short- and medium-range order, and internal electromagnetic fields.

Scanning microwave impedance microscopy is a nearfield technique using microwaves to probe the electrical properties of materials with nanoscale lateral resolution.

Four-dimensional scanning transmission electron microscopy (4D-STEM) is a spatially resolved electron diffraction technique that records the electron scattering distribution at each sampling point. 4D-STEM provides researchers with information that can be analyzed in a multitude of ways to characterize a sample’s structure, including imaging, strain measurement, and defect analysis. This article introduces the basics of the technique and some areas of application with an emphasis on semiconductor materials.

Off-axis electron holography is a TEM-based imaging technique that reveals dopant anomalies and junction profiles in semiconductor devices. This article explains how the method works and how it is being used to visualize transistor source-drain regions, diffusion-related defects, and other features of interest in TEM samples. It also discusses related challenges and compares off-axis electron holography with other profiling techniques, particularly junction staining.

The shrinking geometries in today’s 3-D integrated circuit (IC) designs generate an urgent need for a variety of tools to isolate failures on advanced semiconductor devices. There has been no single technique that adequately addresses all types of failures with the required fast cycle time. Complex failures that are not resolved by the faster global approaches are best addressed by probing technologies, where waveforms or voltages are measured from node to node. These approaches are time-consuming and usually require detailed understanding of the circuit operation. Global techniques that map the secondary effects of defects have been widely used for as many failures as possible. These secondary effects include thermal emission, photon emission, and circuit operation dependencies on localized heating or carrier generation at a defect site. Each technique addresses some segment of the failure mechanisms, but none is universally effective in itself. The use of thermal emission techniques has waned due to the issues of lower power supply voltages, which result in poor sensitivity for older techniques and decrease in minimum resolved feature sizes.

This article describes how physical attacks can be launched on different types of nonvolatile memory (NVM) cells using failure analysis tools. It explains how the bit information stored inside these devices is susceptible to read-out and fault injection attacks and defines vulnerability parameters to help quantify risks associated with different modalities of attack. It also presents an in-depth security analysis of emerging NVM technologies and discusses potential countermeasures.

Localizing defects in one-of-a-kind failures can take days, weeks, or even months, after which a detailed physical analysis is conducted to determine the root cause. TEM and STEM play complimentary roles in this process; TEM because of its superior spatial resolution and STEM because it produces images that are easier to interpret and is less susceptible to chromatic aberrations that can occur in thicker samples. In the past, the use of STEM in FA has been limited due to the time required to switch between imaging modes, but with the emergence of TEM/STEM microscopes with computer controlled lenses, the use of STEM is increasing. This article provides an overview of STEM techniques and present examples showing how it is used to characterize subtle and complex defects in ICs.

Researchers at Boston University have made significant improvements in the resolution that can be achieved with backside imaging techniques. In this article, they explain how they optimize lateral and longitudinal resolution of IR-based methods using aplanatic solid immersion lenses in combination with adaptive optics that correct for aberrations, interferometry to improve signal-to-noise ratios, vortex beams that overcome diffraction limitations, and image reconstruction techniques based on prior knowledge about the objects under investigation.

Wafer-level failure analysis plays an important role in IC fabrication, both in process development and yield enhancement. This article outlines the general flow for wafer-level FA and explains how it differs for memory and logic products. It describes the tools and procedures used for failure mode verification, electrical analysis, fault localization, sample preparation, chemical analysis, and physical failure analysis. It also discusses the importance of implementing corrective actions and tracking the results.

Failure analysis is becoming increasingly difficult with the emergence of 3D integrated packages due to their complex layouts, diverse materials, shrinking dimensions, and tight fits. This article demonstrates several FA techniques, including high-frequency scanning acoustic microscopy, lock-in thermography, and FIB cross-sectioning in combination with plasma ion etching or laser ablation. Detailed case studies show how the various methods can be used to analyze bonding integrity between different materials, chip-to-chip interface structures, buried interconnect defects, and through-silicon vias at either the device or package level.