This article provides a brief overview of STEM-in-SEM, discussing the pros and cons, recent advancements in detector technology, and the emergence of 4D STEM-in-SEM, a relatively new method that uses diffraction patterns recorded at different raster positions to enhance images offline in selected regions of interest.

This article describes two innovative methods that can significantly improve the resolution of SEM imaging: scanning transmission electron microscopy in a scanning electron microscope (STEM-in-SEM) and forward-scattered electron imaging (FSEI). Both methods can be implemented in any SEM using special sample holders. No other modifications are required. Test results presented in the article show that 1 to 2 nm resolution is possible in thin sections, uncoated polysilicon gates, and photoresist.

STEM-EBIC imaging, a nano-characterization technique, has been used in the study of electrically active defects, minority carrier diffusion length, surface recombination velocity, and inhomogeneities in Si pn junctions. In this article, the authors explain how they developed and built a STEM-EBIC system, which they then used to determine the junction location of an InGaN quantum well LED. They also developed a novel FIB-based sample preparation method and a custom sample holder, facilitating the simultaneous collection of Z-contrast, EBIC, and energy dispersive spectroscopy images. The relative position of the pn junction with respect to the quantum well was found to be 19 ± 3 nm from the center of well.

Scanning electron microscopes (SEMs) are the dominant tool for electronic device testing, failure analysis, and characterization. This status was not apparent, however, when the first commercial SEM, the Cambridge Stereoscan, appeared in 1963. A market survey by the manufacturer at that time predicted total sales of six to ten units worldwide. For the last four decades, SEMs have sold at an average rate of one unit every 24 hours, with two out of every three instruments destined for the semiconductor industry.

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.

Electronic device failure analysis usually starts with electrical testing, followed by visual inspection via optical microscopy, then examination in a scanning electron microscope. When imaging reveals the need to determine the composition of materials, defects, and suspected contaminants, the electron beam produced by the SEM can be used to obtain the necessary information. As the article explains, this is the basic concept behind the method known as energy dispersive X-ray spectroscopy (EDS or EDX) and the key to its widespread use. In addition, the article presents three examples showing how SEM/EDS measurements helped failure analysts identify human contaminants on a die sample, determine the source of a particle embedded in the film stack on a wafer, and conclude that lead spatter from a solder die-attach preform caused wire bond lift.

Voltage contrast, a phenomenon that occurs in scanning electron microscopes, produces brightness variations in SEM images that correspond to potential variations on the test sample. Through appropriate processing, voltage contrast signals can reveal an extensive amount of information about the functionality of ICs. Voltage contrast can be used, for example, to map electrical logic levels and timing waveforms from internal nodes of the chip as it operates inside the SEM chamber. This article describes the fundamentals of voltage contrast and its applications in IC failure analysis.

Scanning electron microscopes can be used to analyze almost anything that conducts electricity and is prone to failure, including relays, coils, inductors, capacitors, resistors, transistors, diodes, IGBTS, MOSFETS, and hybrid circuits. As the author of the article explains, SEMs are one of the most versatile tools for failure analysis if used to the full extent of their capabilities. Their operating modes include emissive imaging, backscattering, voltage contrast, EBIC or specimen current, and conductivity resistive mapping. The author describes each operating mode and presents examples of the various ways they can be used.

Improved X-ray detector technology continues to be a critical need in the semiconductor industry, particularly for high-spatial-resolution X-ray microanalysis using lowbeam-voltage field-emission scanning electron microscopes (FE-SEMs). In response to this need, a prototype microcalorimeter energy-dispersive spectrometer has been developed. This article discusses the capabilities of the new tool and demonstrates its use in thin-film and particle analysis. It also discusses ongoing development efforts and potential future advancements.

A new and improved sample preparation technique was developed by Wang. This technique uses an FIB instrument for the 90° rotation of a small portion of the specimen on the original grid by taking advantage of static force. All sample preparation steps, including thin-section creation and sample tilting, can be accomplished in a single process. The procedure is monitored in a high-resolution FIB instrument to assure a 100% success rate. Figure 1 shows a scanning electron microscope image of a 3D TEM sample with two rotated sections. The original TEM sample is a lift-out sample laid on carbon film.

This article describes an ebook titled STEM-in-SEM: Introduction to Scanning Transmission Electron Microscopy for Microelectronics Failure Analysis , intended as an introductory tutorial for those with little or no transmission imaging experience and as a source of ideas for SEM users looking to expand the imaging and diffraction capabilities of their equipment.

This article discusses the advantages of SEM-based nanoprobing and the various ways it can be used to locate defects associated with IC failures. It describes the basic measurement physics of electron beam induced current, absorbed electron, and voltage distribution contrast imaging and presents examples showing how the different methods are used to isolate low- and high-resistance sites, shorts, and opens as well as ion implantation and metal patterning defects.

This article provides an introduction to scanning ion microscopy, explaining how it overcomes one of the biggest limitations of SEMs, namely the tradeoff between spatial resolution and depth of field, while also providing significantly more surface detail, a wide range of novel and familiar contrast mechanisms, and the potential for new microanalytical techniques that combine nanometer spatial resolution and single monolayer sensitivity. In addition to describing the capabilities of scanning ion microscopes, the article also addresses the issue of sample charging and the potential for physical damage that can result from ion beam irradiation.

This article presents the principles of scanning thermal microscopy (SThM) instruments and their potential uses for the local thermal analysis of passive and active electronic components and devices. Three examples are given that demonstrate the SThM’s ability to perform thermal analysis on a microscopic scale. The results suggest that SThM could be used as a powerful tool for analyzing printed circuit boards and electronic devices with high spatial resolution, during the development cycle, failure analysis during and after manufacture, and during operation.

Advances in IC technology have made failure site localization extremely challenging. Through a series of case studies, the authors of this article show how such challenges can be overcome using EBIC/EBAC, current imaging, and nanoprobing. The cases involve a wide range of issues, including resistor chain defects, substrate leakage, microcracking, micro contamination, and open failures due to copper plating problems and missing vias.

This is the second article in a two-part series on deep ultraviolet (DUV) microscopy. The first part, published in the February 2000 issue of EDFA, discusses the working principles and capabilities of the method and the types of applications for which it is suited. In this issue, the author describes the basic design of DUV microscopes, the role of major components, and their effect on imaging quality.

This column describes a unique arrangement between two IC manufacturers that built and share a state-of-the-art failure analysis laboratory. The lab is dedicated to helping the two companies characterize their new technologies, debug new designs, measure IC performance, find defects responsible for yield loss, and improve product reliability. In addition to discussing the technical capabilities of the lab, our guest columnist also explains how the lab is funded and managed.

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.

Probing in the sub-100 nm realm requires new tools and techniques that are relatively easy to learn if users follow the advice of the authors of this article. The authors present a probing method based on scanning probe technology and demonstrate its use on a 90-nm transistor failure due to a poly-silicon gate short. They also address challenges associated with sample preparation, probe tip contamination and wear, and the effects of vibration and drift.

This article provides a practical overview of energy-dispersive spectroscopy (EDS) and its various uses in semiconductor device manufacturing and failure analysis. It explains how EDS techniques are typically implemented, compares and contrasts different methods, and discusses the factors that determine spatial and energy resolution, measurement depth, sensitivity, signal-to-noise ratio, and ease of use.