With semiconductor device dimension continuously scaling down and increasing complexity in integrated circuits, delayering techniques for reverse engineering is becoming increasingly challenging. The primary goal of delayering in semiconductor failure analysis is to successfully remove layers of material in order to locate and identify the area of interest. Several of the top-down delayering techniques include wet chemical etching, dry reactive ion etching, top-down parallel lapping (including chemical-mechanical polishing), ion beam milling and laser delayering techniques. This article discusses the general procedure, types, advantages, and disadvantages of each of these techniques. In this article, two types of different semiconductor die level backend of line technologies are presented: aluminum metallization and copper metallization.

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.

The need for precise targeted interactive surgery on boards or modules is the main driver of backside preparation technology. This article assists the analyst in making decisions on backside thinning and polishing requirements. Thinning of the substrates can be accomplished by flat lapping, laser assisted chemical etch, plasma reactive ion etch, and CNC based milling and polishing. The article discusses the general characteristics, key principles, advantages, and disadvantages of these processes. It also contains case studies that illustrate the application of these processes to ceramic cavity devices, injection molded parts, and ball grid arrays.

The orientation of the devices within a package determine the best chosen approach for access to a select component embedded in epoxy both in package or System in Package and multi-chip module (MCM). This article assists the analyst in making decisions on frontside access using flat lapping, chemical decapsulation, laser ablation, plasma reactive ion etching (RIE), CNC based milling and polishing, or a combination of these coupled with optical or electrical endpoint means. This article discusses the general characteristics, advantages, and disadvantages of each of these techniques. It also presents a case study illustrating the application of CNC milling to isolate MCM leakage failure.

This appendix lists etch compositions and procedures that reveal strain patterns in aluminum and nickel-base superalloys.

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.

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.

The first step in die-level failure analysis is to narrow the search to a specific circuit or transistor group. Then begins the post-isolation process which entails further localizing the defect, determining its electrical, physical, and chemical properties, and examining its microstructure in order to identify the root cause of failure. This chapter assesses the tools and techniques used for those purposes and the challenges brought on by continued transistor scaling, advanced 3D packages, and new IC architectures. The areas covered include sample preparation, nanoprobing, microscopy, FIB circuit edit, and scanning probe microscopy.

This chapter discusses field, visual, physical, and metallurgical examinations of gear failures. Physical examinations reviewed include nondestructive testing, including magnetic-particle inspection, tooth characteristic studies, surface hardness testing, ultrasonic testing, nital etching, profilometer measurements, and dimensional checking. Metallurgical examinations reviewed include the cross-sectional hardness survey, macroscopic examination, carbon gradient traverse, chemical analysis, case hardness traverse [microhardness], microscopic examination, and scanning electron microscopy.

This chapter discusses the important aspects that a metallographer should understand in order to effectively reveal a microstructure. It begins by exploring etching response and how it can be a tool for revealing various microstructural features. The next part of the chapter discusses methods for revealing microstructure in the as-polished (unetched) specimen, then guidelines for selecting and using etchants when needed. The chapter discusses different types of etchants in terms of their ingredients, etching procedure, and major uses. The etchants discussed include basic etchants (nital and picral and their variations) and tint etchants for carbon and low-alloy steels and cast irons, and basic etchants for stainless steels. Finally, information is provided on different illumination methods (differential interference contrast and dark-field illumination) that can be used to highlight certain features in microstructures.