Xenon plasma focused ion beam specimen preparation is ideal for preparing plan view TEM specimens due to its large-volume-milling capabilities. This article describes concentrated Ar ion beam milling using low energy as a post-pFIB final thinning step of plan view TEM specimens from a phase change memory device. Precise control of specimen thinning is achieved, which results in high-quality specimens with pristine surfaces and a large field of view for TEM characterization.

TEM specimens prepared using a Ga FIB are susceptible to artifacts, such as surface amorphization and ion-implanted layers, that can be problematic in advanced technology nodes, particularly for FinFETs. As this article shows, however, post-FIB cleaning via concentrated argon ion milling makes for a fast and effective specimen preparation process for FinFET devices controlled to a thickness of less than 20 nm. Although the results presented here are based on 14 nm node FinFETs, the method is also applicable to the 10 and 7 nm FinFET technologies currently in production.

Transmission electron microscopy (TEM) plays an important role semiconductor process development, defect identification, yield improvement, and root-cause failure analysis. At the same time, however, certain artifacts of specimen preparation and imaging present barriers for linear scaling of TEM techniques. This article assesses these challenges and explains how electron tomography is being used to overcome them.

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.

Ex-situ lift out (EXLO) techniques rely on van der Waals forces to transfer FIB milled specimens to various types of carriers using a glass probe micromanipulator. This article describes some of the latest EXLO techniques for site specific scanning transmission electron microscopy, including the use slotted half-grids and vacuum-assisted lift out for plan-view analysis.

The combination of microcleaving and precision broad ion beam techniques allows failure analysts to prepare site-specific specimens for SEM analysis with 0.5 μm accuracy. Microcleaving, as the article explains, uses the cleaving characteristics inherent in single-crystal semiconductor substrates. Because the substrate has significantly more mass than the process layers, it dictates the overall cross-section quality and precision of the sample. The cleave loses no material, preserves the integrity of the designated area, and enables analysis of both sides of the cross-section. When the cleave is off-set due to a buried target or when debris lies on the surface of the cross-section, ion beam etching and coating are used to fine tune the cleave location and remove debris prior to SEM analysis.

New materials integration and improved design can be promoted by using atom probe tomography (APT) as an analysis technique. This article provides an overview of APT principles and setups and provides diverse examples that focus on its use to characterize electronic devices.

This article discusses the practice of FIB-based in situ lift-out, a sample preparation method that has proven particularly useful for failure analysis. It explains how samples are now being made for a wide range of TEM techniques, including holography, tomography, high-angle annular dark-field scanning, and electron energy-loss spectroscopy. In most cases, achieving optimal quality requires the use of alternate FIB milling angles, as in plan-view, sideways, and backside milling, all of which are discussed.

This is the story of how the mainstream Omniprobe FIB lift-out solution was invented and delivered to the market.

This article discusses the basic procedures involved in atom probe tomography (APT) and demonstrates its use on complex material stacks. Although still a relatively new technique, APT has moved to the forefront of semiconductor failure analysis because it can provide 3D chemical composition of a wide range of materials on a near-atomic scale.

This article compiles summaries of User Group meetings held at ISTFA 2013, including the Contactless Fault Isolation User’s Group, the Focused Ion Beam User’s Group, the Sample Prep/3D Package User’s Group, and the Nanoprobing User’s Group. For each meeting, a brief synopsis of the presentations and subsequent dialog is provided.

This article provides an overview of atom probe tomography (APT) and its use in semiconductor FA and new product development. It discusses the basic components in an atom probe, the making of APT tips, and the general approach for data collection and reconstruction. It also includes a case study in which 3D atom probe techniques are used to map dopant profiles and identify defects in the source-drain region of SiGe FinFET transistors.

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.

This article describes a sample preparation technique by which specific areas on integrated circuits can be manually polished to TEM transparency. The technique, called tripod polishing or the wedge method, produces cross-section samples within a few hours that require little or no additional thinning for TEM analysis. The method can also be used to prepare plan view TEM samples as well as samples for SEM analysis and light microscopy.

This article describes how focused ion beam (FIB) technology is being used in combination with various other analytical tools for failure and yield analysis of MEMS devices. It provides examples showing how FIB is used with TEM analysis, AFM analysis, scanning acoustic microscopy, and scanning laser microscopy.

The sixth FIB-SEM workshop was held March 1, 2013, in Cambridge, Mass. This article provides a summary of the event along with highlights from the 18 paper presentations.

This article provides a summary of the presentations given at the four User’s Group meetings at ISTFA 2012. Each user group focused on one of the following topics: nanoprobing, contactless fault isolation, focused ion beam, and sample preparation.

With the growing complexity of new processes and the introduction of new materials, the need for product yield management and process control is placing unprecedented demands on failure analysis laboratories in the semiconductor industry. These demands are calling for faster and superior analytical capabilities to determine root-cause failure mechanisms in semiconductor devices fabricated using deep submicron processes. This article presents a new automated sample preparation technique that facilitates direct electrical contact to the area of interest, with a surface quality sufficient for scanning probe microscope analysis.

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.

The scribe-and-cleave method is a widely used sample preparation technique, although numerous challenges make it less than ideal. A new indent-and-cleave approach described in this article provides improved results, even on samples previously considered uncleavable. Several case studies are presented to demonstrate the capabilities of the new technique.