The analysis of composite materials using optical microscopy is a process that can be made easy and efficient with only a few contrast methods and preparation techniques. This chapter is intended to provide information that will help an investigator select the appropriate microscopy technique for the specific analysis objectives with a given composite material. The chapter opens with a discussion of macrophotography and microscope alignment, and then goes on to describe various illumination techniques that are useful for specific analysis requirements. These techniques include bright-field illumination, dark-field illumination, polarized-light microscopy, interference and contrast microscopy, and fluorescence microscopy. The chapter also provides a discussion of sample preparation materials such as dyes, etchants, and stains for the analysis of composite materials using optical microscopy.

This chapter discusses the tools and techniques of light microscopy and how they are used in the study of materials. It reviews the basic physics of light, the inner workings of light microscopes, and the relationship between resolution and depth of field. It explains the difference between amplitude and optical-phase features and how they are revealed using appropriate illumination methods. It compares images obtained using bright field and dark field illumination, polarized and cross-polarized light, and interference-contrast techniques. It also discusses the use of photometers, provides best practices and recommendations for photographing structures and features of interest, and describes the capabilities of hot-stage and hot-cell microscopes.

Transmitted-light methods reveal more details of the morphology of fiber-reinforced polymeric composites than are observable using any other available microscopy techniques. This chapter describes the various aspects relating to the selection and preparation of ultrathin-section specimens of fiber-reinforced polymeric composites for examination by transmitted-light microscopy techniques. The preparation steps covered are a selection of the rough section, preparation of the rough section for preliminary mounting, grinding and polishing the primary-mount first surface, mounting the first surface on a glass slide, and preparing the second surface (top surface). The optimization of microscope conditions and analysis of specimens by microscopy techniques are also covered. In addition, examples of composite ultrathin sections that are analyzed using transmitted-light microscopy contrast methods are shown throughout.

Contaminants can be a cause of numerous types of system failures. There are numerous techniques for confirming contaminant presence. When the presence of a contaminant is suspected, the failure analysis team must find and eliminate the contaminant source, which can be obvious or quite subtle. This chapter summarizes a few commonly encountered contaminant sources to stimulate the reader's thinking about potential contaminant sources. A case study of titanium component washing at Litton Lasers is presented to illustrate how the presence of contaminants leads to a system failure.

The scanning acoustic microscope (SAM) is an important tool for development of improved molded and flip chip packages. The SAM used for integrated circuit inspection is a hybrid instrument with characteristics of both the Stanford SAM and the C-scan recorder. This chapter presents the historical development of SAM for integrated circuit package inspection, SAM theory, and analysis considerations. Case studies are presented to illustrate the practical applications of SAM. Other non-destructive imaging tools are briefly discussed, as well as SAM challenges and methods including spectral signature analysis and GHz-SAM.

This chapter describes some of the most effective tools for investigating boiler tube failures, including scanning electron microscopy, optical emission spectroscopy, atomic absorption spectroscopy, x-ray fluorescence spectroscopy, x-ray diffraction, and x-ray photoelectron spectroscopy. It explains how the tools work and what they reveal. It also covers the topic of image analysis and its application in the measurement of grain size, phase/volume fraction, delta ferrite and retained austenite, inclusion rating, depth of carburization/decarburization, scale thickness, pearlite banding, microhardness, and hardness profiles. The chapter concludes with a brief discussion on the effect of scaling and deposition and how to measure it.

Moore's Law has driven many degree circuit features below the resolving capability of optical microscopy. Yet the optical microscope remains a valuable tool in failure analysis. This article describes the physics governing resolution and useful techniques for extracting the small details. It begins with the basic microscope column and construction. The article discusses microscope adjustments, brightfield and darkfield illumination, and microscope concepts important to liquid crystal techniques. It also discusses solid immersion lenses, infrared and ultraviolet microscopy and concludes with laser microscopy techniques such as thermal induced voltage alteration and external induced voltage alteration.

As semiconductor feature sizes have shrunk, the technology needed to encapsulate modern integrated circuits has expanded. Due to the various industry changes, package failure analyses are becoming much more challenging; a systematic approach is therefore critical. This article proposes a package failure analysis flow for analyzing open and short failures. The flow begins with a review of data on how the device failed and how it was processed. Next, non-destructive techniques are performed to document the condition of the as-received units. The techniques discussed are external optical inspection, X-ray inspection, scanning acoustic microscopy, infrared (IR) microscopy, and electrical verification. The article discusses various fault isolation techniques to tackle the wide array of failure signatures, namely IR lock-in thermography, magnetic current imaging, time domain reflectometry, and electro-optical terahertz pulse reflectometry. The final step is the step-by-step inspection and deprocessing stage that begins once the defect has been imaged.

This appendix is a compilation of suggested analysis methods for suspected component failure causes.

This chapter explains how to achieve accurate, sharp delineation of the microstructure of metals using appropriate etching and contrasting techniques. It covers a variety of methods, including chemical etching, heat tinting, gas contrasting, vapor deposition, magnetic etching, ion bombardment, and dislocation etch pitting.

A design modification intended to reduce dowel bolt failures in an aircraft engine proved ineffective, prompting an investigation to determine what was causing the bolts to break. As the chapter explains, failure specimens were examined under various levels of magnification and subjected to chemical analysis and low-cycle fatigue tests. Based on their findings, investigators concluded that the bolts failed due to fatigue compounded by excessive clearances and poor surface finishes. The chapter provides a number of recommendations addressing these issues and related concerns.

The second-generation composite materials were added to increase the strain to failure of the primary phase and/or create a dispersed second phase, thereby enhancing the fracture toughness of the thermosetting matrix. These matrices offered novel design capabilities for composites in a variety of aircraft applications. To improve the damage tolerance of composite materials even further, an engineering approach to toughening was used to modify the highly stressed interlayer with either a tougher material or through the use of preformed particles, leading to the third generation of composite materials. This chapter discusses the development, processes, application, advantages, and disadvantages of dispersed-phase toughening of thermoset matrices. Information on the processes of particle interlayer toughening of composite materials is also included.

The ultimate goal of the failure analysis process is to find physical evidence that can identify the root cause of the failure. Transmission electron microscopy (TEM) has emerged as a powerful tool to characterize subtle defects. This article discusses the sample preparation procedures based on focused ion beam milling used for TEM sample preparation. It describes the principles behind commonly used imaging modes in semiconductor failure analysis and how these operation modes can be utilized to selectively maximize signal from specific beam-specimen interactions to generate useful information about the defect. Various elemental analysis techniques, namely energy dispersive spectroscopy, electron energy loss spectroscopy, and energy-filtered TEM, are described using examples encountered in failure analysis. The origin of different image contrast mechanisms, their interpretation, and analytical techniques for composition analysis are discussed. The article also provides information on the use of off-axis electron holography technique in failure analysis.

This chapter focuses on common failure characteristics exhibited by mechanical and electrical components. The topic is considered from two perspectives: one possibility is that the system failed because parts were nonconforming to drawing requirements and another possibility is that the system failed even though all parts in the system met their drawing requirements. The common failures discussed in this chapter include those associated with metallic components, composite materials, plastic components, ceramic components, and electrical and electronic components.

The overall chemical composition of metals and alloys is most commonly determined by x-ray fluorescence (XRF) and optical emission spectroscopy (OES). High-temperature combustion and inert gas fusion methods are typically used to analyze dissolved gases (oxygen, nitrogen, and hydrogen) and, in some cases, carbon and sulfur in metals. This chapter discusses the operating principles of XRF, OES, combustion and inert gas fusion analysis, surface analysis, and scanning auger microprobe analysis. The details of equipment set-up used for chemical composition analysis as well as the capabilities of related techniques of these methods are also covered.

The complexity of semiconductor chips and their packages has continuously challenged the known methods to analyze them. With larger laminates and the inclusion of multiple stacked die, methods to analyze modern semiconductor products are being pushed toward their limits to support these 2.5D and 3D packages. This article focuses on these methods of fault isolation, non-destructive imaging, and destructive techniques through an iterative process for failure analysis of complex packages.

Photon emission (PE) is one of the major optical techniques for contactless isolation of functional faults in integrated circuits (ICs) in full electrical operation. This article describes the fundamental mechanisms of PE in silicon based ICs. It presents the opportunities of contactless characterization for the most important electronic device, the MOS - Field Effect Transistor, the heart of ICs and their basic digital element, the CMOS inverter. The article discusses the specification and selection of detectors for proper PE applications. The main topics are image resolution, sensitivity, and spectral range of the detectors. The article also discusses the value and application of spectral information in the PE signal. It describes state of the art IC technologies. Finally, the article discusses the applications of PE in ICs and also I/O devices, integrated bipolar transistors in BiCMOS technologies, and parasitic bipolar effects like latch up.

Magnetic field imaging (MFI), generally understood as mapping the magnetic field of a region or object of interest using magnetic sensors, has been used for fault isolation (FI) in microelectronic circuit failure analysis for almost two decades. Developments in 3D magnetic field analysis have proven the validity of using MFI for 3D FI and 3D current mapping. This article briefly discusses the fundamentals of the technique, paying special attention to critical capabilities like sensitivity and resolution, limitations of the standard technique, sensor requirements and, in particular, the solution to the 3D problem, along with examples of its application to real failures in devices.

This chapter describes the methods and equipment applicable to metallographic studies and discusses the preparation of specimens for examination by light optical microscopy. Five major operations for preparation of metallographic specimens are discussed: sectioning, mounting, grinding, polishing, and etching. The discussion covers their basic principles, advantages, types, and applications, as well as the equipment setup. The chapter includes tables that list etchants used for microscopic examination. It also provides information on microscopic examination, microphotography, and the effects of grain size on the structural properties of the material.