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.

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.

The mechanical properties of steel are strongly influenced by the underlying microstructure, which is readily observed using optical microscopy. This chapter describes common room-temperature steel microstructures and how they are achieved via heat treatment. It discusses the production of hypo- and hypereutectoid steels and the effect of cooling rate on microstructure. It also examines quenched steels and the phase transformations associated with rapid cooling. It describes the development of lath and plate martensite, retained austenite, and bainite and how to identify the various phases. The chapter concludes with a brief review of spheroidized microstructures.

This chapter describes the various features of the metallurgical microscope. Key concepts are defined such as resolving power, the virtual image, bright- and dark-field illumination, numerical aperture, focal length, image contrast, depth of field, and spherical and chromatic aberration. Metallurgical microscope features such as apochromatic objectives, hyperplane oculars, vertical illuminators, counting reticles, widefield oculars, polarization filters, field diaphragms, interferometers, and tungsten-halogen lamps are explained. The optical system, nosepiece, types of objectives (the lens assembly close to the specimen) and eyepieces, and components of the illumination system are all explained. The last part of this chapter describes special procedures involved in using and calibrating the metallurgical microscope.

This appendix contains detailed micrographs of nickel- and cobalt-base superalloys selected to illustrate the microstructural features described in this book.

This chapter explains how to prepare material samples for optical microscopy, the most common method for characterizing the microstructure of cast iron and steel. It provides information on sectioning, mounting, polishing, etching, and recording. It describes the nature of surface roughness, the factors that contribute to it, and its effect on image quality. It discusses the use of fixturing and holding devices, includes photographic examples of polishing defects and drying marks, and provides an overview of micrographic etchants and the features they reveal. It also describes the steps involved in replicating part surfaces.

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.

This chapter provides an overview of the tools and techniques used to examine failure specimens and the wealth of information that can be obtained from fracture surfaces, cracks, wear patterns, and other such features. It discusses the use of metallography, fractography, and optical and electron microscopy. It presents a number of images recorded using these methods and explains what they reveal about the mode of fracture and the state of the component prior to failure.

After several failed attempts to lower their starboard wheels for landing, pilots engaged the help of gravity through g-force maneuvers and managed to coax the wheels into place. An inspection following the incident revealed a broken universal joint in one of the linkages that opens and closes the doors to the undercarriage compartment. The failed component was removed from the aircraft and examined using optical and electron microscopes. Under low magnification, the fracture surface appeared jagged except for one corner that was relatively smooth. SEM fractography revealed the presence of fatigue striations in the smooth region and dimpling elsewhere. Based on their findings, investigators concluded that fatigue loading initiated a crack in the universal joint that progressed with time and that the final fracture occurred due to bending tensile overload.

The quill shaft in an aircraft engine was found in two pieces following a flameout. One piece was short, straight, and otherwise undamaged; the other piece was bent in several places as was the sleeve that covered it. The facture surface, as viewed under optical and scanning electron microscopes, was flat and shiny with deformation marks and dimples, typical of torsional overload, and signs of severe rubbing on the periphery. Based on their observations, investigators concluded that the quill shaft failed by torsional overload, the source of which could not be determined.

A pair of bolts on a connecting rod failed during a test run for a prototype engine. They were replaced by bolts made from a stronger material that also failed, one due to fatigue, the other by tensile overload. The fracture surfaces on all four bolts were examined using optical and electron microscopes, indicating that the operating loads on the bolts far exceeded the design loads. Based on their observations, which are summarized in the report, failure analysts concluded that the design of the connecting rod system needs to be reassessed.

Education and training play an important role if the failure analyst is to be successful in his or her work. This article discusses the history of training activities in the failure/product analysis discipline and describes where this area is heading. It provides information on three areas of education and training that should be given to the analyst for him or her to be successful developing and fielding modern semiconductor components: analysis process, technology, and technique training.

This article reviews the basic physics behind active photon injection for local photocurrent generation in silicon and thermal laser stimulation along with standard scanning optical microscopy failure analysis tools. The discussion includes several models for understanding the local thermal effects on metallic lines, junctions, and complete devices. The article also provides a description and case study examples of multiple photocurrent and thermal injection techniques. The photocurrent examples are based on Optical Beam-Induced Current and Light-Induced Voltage Alteration. The thermal stimulus examples are Optical Beam-Induced Resistance Change/Thermally-Induced Voltage Alteration and Seebeck Effect Imaging. Lastly, the article discusses the application of solid immersion lenses to improve spatial resolution.

This article provides an overview of how to use the scanning electron microscope (SEM) for imaging integrated circuits. The discussion covers the principles of operation and practical techniques of the SEM. The techniques include sample mounting, sample preparation, sputter coating, sample tilt and image composition, focus and astigmatism correction, dynamic focus and image correction, raster alignment, and adjusting brightness and contrast. The article also provides information on achieving ultra-high resolution in the SEM. It concludes with information on the general characteristics and applications of environmental SEM.

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.

Steels are over 95% Fe, so a good starting point for understanding steel is to study the nature of solid iron. This chapter provides information on the composition, phase transformation, and associated changes in the crystal structure of pure iron at varying temperatures.

This article introduces the wafer-level fault localization failure analysis (FA) process flow for an accelerated yield ramp-up of integrated circuits. It discusses the primary design considerations of a fault localization system with an emphasis on complex tester-based applications. The article presents examples that demonstrate the benefits of the enhanced wafer-level FA process. It also introduces the setup of the wafer-level fault localization system. The application of the wafer-level FA process on a 22 nm technology device failing memory test is studied and some common design limitations and their implications are discussed. The article presents a case study and finally introduces a different value-add application flow capitalizing on the wafer-level fault localization system.

This article introduces the subject of fractography and how it is used in failure analysis. The discussion covers the structure of and fracture and crack-propagation behavior of polymeric materials, the distinction between the ductile and brittle fracture modes on the basis of macroscopic appearance, and the examination and interpretation of the features of fracture surfaces. In addition, the article considers several cases of field failure in various polymers to illustrate the applicability of available analytical tools in conjunction with an understanding of failure mechanisms.

This article presents methods that enable one to consistently, uniformly and quickly remove substrate silicon from units without imparting damage to the structure of interest. It provides examples of electron beam probing and backside nano-probing techniques. The electron beam probing techniques are E-beam Logic State Imaging, Electron-beam Signal Image Mapping, and E-beam Device Perturbation. Backside nano-probing techniques discussed include: Electron Beam Absorbed Current, Electron Beam Induced Resistance Change, four terminal resistance measurements, resistive gate defect identification, and circuit editing. The article also presents methods to prepare electron beam probing samples where some remaining silicon is required for the transistor functions and transmission electron microscope samples from units where the substrate silicon has been partially or completely removed.

Since the introduction of chip scale packages (CSPs) in the early 90s, they have continuously increased their market share due to their advantages of small form factor, cost effectiveness and PCB optimization. The reduced package size brings challenges in performing failure analysis. This article provides an overview of CSPs and their classification as well as their advantages and applications, and reveals some of the challenges in performing failure analysis on CSPs, particularly for CSPs in special package configurations such as stacked die multi-chip-packages (MCPs) and wafer level CSPs (WLCSPs). The discussion covers special requirements of CSPs such as precision decapsulation for fine ball grid array packages, accessing the failing die for MCP packages, and careful handling for WLCSP. Solutions and best practices are shared on how to overcome these challenges. The article also presents a few case studies to demonstrate how failure analysis work on CSPs can be successfully completed.