Search Results for optical analysis

Rough grinding and polishing of mounted specimens are required to prepare the composite sample for optical analysis. This chapter describes these techniques for preparing composite materials. First, it provides information on grinding and polishing equipment and describes the processes and process variables for sample preparation. Then, the chapter discusses the processes of abrasive sizing for grinding and rough polishing. Next, it provides a summary of grinding methods, rough polishing, and final polishing. Finally, information on common polishing artifacts that can result from any of the steps is provided.

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.

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.

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.

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.

Laser Voltage Probing (LVP) is a key enabling technology that has matured into a well-established and essential analytical optical technique that is crucial for observing and evaluating internal circuit activity. This article begins by providing an overview on LVP history and LVP theory, providing information on electro-optical effects and free-carrier effects. It then focuses on commercially available continuous wave LVP systems. Alternative optoelectronic imaging and probing technologies for fault isolation, namely frequency mapping and laser voltage tracing, are also discussed. The subsequent section provides information on the use of Visible Laser Probing. The article closes with some common LVP observations/considerations and limitations and future work concerning LVP.

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.

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.

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.

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 provides an introduction to the dynamic random access memory (DRAM) operation with a focus to localization techniques of the defects combined with some physical failure analysis examples and case studies for memory array failures. It discusses the electrical measurement techniques for array failure analysis. The article then presents know-how-based analysis techniques of array failures by bitmap classification. The limits of bitmapping that lead to well-known localization techniques like thermally induced voltage alteration and optical beam induced resistance change are also discussed. The article concludes by providing information on soft defect localization techniques.

After the fault-tree, a failure-cause identification method has identified potential failure causes and the failure analysis team has prepared a failure mode assessment and assignment (FMA&A). The team knows specifically what to search for when examining components and subassemblies from the failed system. There are numerous techniques and technologies available for examining and analyzing components and subassemblies, which are categorized as follows: optical approaches, dimensional inspection and related approaches, nondestructive test approaches, mechanical and environmental approaches, and chemical and composition analysis for assessing material characteristics. This chapter is a detailed account of the working principle and the steps involved in these techniques and technologies.

This chapter assesses the capabilities and limitations of electric fault isolation (EFI) technology, the measurement challenges associated with new device architectures, and the pathways for improvement in emission microscopy, laser stimulation, and optical probing. It also assesses the factors that influence signal strength, spatial and timing resolution, and alignment accuracy between signal response images and the physical layout of the IC.

This chapter assesses the benefits of using a solid immersion lens (SIL) to detect faults in ICs via optical imaging and laser-stimulation techniques. It discusses the advantages and limitations of different types of SILs and their effect on spatial resolution, spot size, focus depth, and collection efficiency. It also provides a brief overview of technical challenges at the die level.

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.

This chapter elucidates the indispensable role of characterization in the development of cold-sprayed coatings and illustrates some of the common processes used during coatings development. Emphasis is placed on the advanced microstructural characterization techniques that are used in high-pressure cold spray coating characterization, including residual-stress characterization. The chapter includes some preliminary screening of tool hardness and bond adhesion strength, as well as a distinction between surface and bulk characterization techniques and their importance for cold spray coatings. The techniques covered are optical microscopy, X-Ray diffraction, scanning electron microscopy, focused ion beam machining, electron probe microanalysis, transmission electron microscopy, and electron backscattered diffraction. The techniques also include electron channeling contrast imaging, X-Ray photoelectron spectroscopy, X-ray fluorescence, Auger electron spectroscopy, Raman spectroscopy, oxygen analysis, and nanoindentation.

Intermetallic phase precipitates in aluminum alloys can often be identified without resorting to chemical analysis. Very often the determination can be made based on the shape, color, and refractive properties of the particular phase. This chapter explains how these visual attributes can be observed using metallographic techniques. It describes, and in many cases illustrates, the characteristic shapes, colors, and optical properties associated with aluminum alloy intermetallic phases and how they can be enhanced through selective etching. It provides an atlas of microstructures comparing the effects of selective etching procedures on various phase constituents in cast aluminum-silicon alloys. The compilation of images demonstrates the use of two types of reagents: those that reveal discontinuities in crystal orientation and grain boundaries, and those that reveal differences in chemical composition.