So you’re having a problem with a printed circuit board assembly (PCBA). You’ve done all you can to narrow down the failure site, but you’re at the limit of the capabilities your equipment has available to you. What do you do now?

The Mil-Std- 883, Method 2018 specifies sampling procedures for die selected from the wafers or die already packaged. In this post, we dive into the purpose and processes required by this standard.

In the current era of System-on-Chip (SoC) designs with 10 and 11 metal layers, copper metallizations, exotic dielectric materials, and the use of area pads scattered across the entire die area of circuit design, FIB provides an ideal diagnostic aid.

Computers used to take up entire rooms to perform what we would consider today rather rudimentary calculations. As computing power increased, the size of the computers decreased. What was once an easily spotted blown tube transistor became very difficult to see electron leakage through a PNP junction. Enter the world of microelectronics. Every mobile electronic device today is powered by microelectronics. They need to be small, fast and reliable. They also need to be durable. When things go wrong with them, we want to know what caused the failure and how it can be fixed to make our electronics as reliable as possible.

In their final, packaged form, many of the secrets of integrated circuits are concealed from an analyst looking to uncover a failure. While techniques like x-ray and acoustic microscopy can penetrate the shroud of mold compound and FR4 that enfold the semiconductor die at the heart of a device and reveal some information, they rarely tell the whole story; to truly determine the root cause of failure, an analyst almost always needs to be able to examine the device directly. This examination may take many forms - optical or electron microscopy may reveal a defect site, or elemental analysis tools may identify contaminants causing corrosion or other issues - so the techniques used to expose the semiconductor die must take into account the potential failure mechanisms that are most likely for any given device. IC decapsulation is the process - part art, part science - of breaking in to these devices to discover what defects might lie within.

The modern electronics consumer is a demanding, discerning individual. The demands placed on any product are extensive; end users expect a wide range of functionality, with high reliability, at low cost. A device as ubiquitous as a smartphone is capable of facilitating transcontinental data transfer, displaying cutting edge graphics, and performing feats of mathematical might, all in a package small enough to fit into a pocket - and at a price point low enough not to empty said pocket. Modern electronic systems require hundreds, if not thousands, of components, all working together in concert to provide the functionality consumers have come to rely on; from the sheer computing power of a cutting-edge microprocessor to the simplicity of a passive capacitor, each component is vital to a device’s operation, since extraneous or redundant parts are trimmed during design in order to minimize costs. When one of these components fail - even one as minor as a surface mount resistor - a device can go from a modern marvel of technology to an extremely expensive inert hunk of plastic and metal. Determining why a device failed is often an excellent first step towards improving the reliability of future generations of products;  electronic…

                The modern electronics and semiconductor markets are fiercely competitive. Manufacturers are constantly vying for supremacy, attempting to carve out a niche with novel, innovative approaches to fulfill the needs and wants of an increasingly demanding customer base. In such a rapidly changing, fast-paced environment, bringing a new product to market can be challenging, especially without any sort of knowledge of how the competition might measure up. Often, a manufacturer looking to break into the market will employ a third party to perform a technical competitive analysis – an in-depth look at the construction of a product that can provide insight into key details like process node, die size, and functional block size that can be used to perform cost and performance analyses. At first blush, technical competitive analyses appear completely separate from failure analysis services; in reality, the tools and techniques developed for finding defects on cutting-edge products translate seamlessly to the type of teardowns necessary to perform a deep dive into the minutiae of a product’s construction.

Failure analysis of consumer electronics can pose a wide variety of challenges, due to the multitude of different failure mechanisms that might befall a device. Environmental factors, mistreatment, and even the way that the device is packaged can contribute to the untimely demise of a device. While the vast majority of integrated circuits are packaged using a plastic or epoxy based mold compound, some high-reliability devices - especially those used in aerospace applications - are encased in hermetically sealed tombs of ceramic and metal. Performing electronic failure analysis of these hermetic packages poses a new set of challenges, as there are certain failure mechanisms and tests that are applicable only to this type of packaging.

Over the course of a failure analyst’s career, they will be exposed to an extensive and varied array of devices. No matter the technology – whether they be nanoscopic silicon sensors with moving parts so small as to defy belief or massive circuit assemblies comprised of thousands of discrete components and integrated circuits – no device is completely immune to failure. Variations in process control, insufficiently robust designs and extended abuse by an end user can all spell early doom for a device. In our introductory article, we took a high-level overview of the failure analysis process, discussing the steps an analyst takes to turn a failing, rejected product into actionable knowledge for process improvement; in this column, we will see how these steps are applied to a specific failure. Naturally, examining a relatively trivial case would not provide the necessary depth of learning, so instead, we choose to give an example of a failure many analysts dread: an intermittent failure on a printed circuit assembly.

                It is an inexorable fact of life that all electronic assemblies – from the most complex, densely interconnected systems to the cheapest mass-produced consumer devices – will eventually fail. Such devices may be victims of various forms of abuse at the hands of their end users, subject to mechanical, environmental, or electrical stresses far beyond what any design engineer would consider reasonable. Some, especially early prototypes, may be inherently flawed and susceptible to malfunction as a result of a simple mistake made during one too many late night, bleary-eyed design review sessions, conducted over energy drinks and cold takeout. Of course, it is also possible for assemblies to simply die of old age; eventually, normal wear and tear will break down even the most robust of electronic devices. In all these cases, the result is the same (at least at a very high level): a device that no longer performs its intended function.

                Modern printed circuit assemblies are vastly complex labyrinths of interconnected devices, comprising many hundreds of components and thousands of individual signals being routed through the networks of metal, silicon, and dielectric material. While the individual integrated circuits on an assembly may steal most of the glory – just look at the buzz surrounding the processors inside the latest and greatest cell phone, video card, or supercomputer – interconnect technology is just as important to the success of a given product. To ensure a robust product, the reliability of the connections between individual components and the PCB that hosts them is paramount; to maximize this reliability, failure analysis of electronic assemblies to investigate solder failures is an excellent springboard to continuous improvement.

The culminating moment of triumph for any failure analysis project is when a defect is captured in all its glory - that instant where the noisy tangle of data and observations are crystallized into a coherent analysis due to the addition of one crowning piece of evidence. While it would seem that the final photograph, showcasing the defect that lies at the root of a failure, would draw a failure analysis project to a close, there is often still work left to do; in many cases, analyzing semiconductor failures requires an even deeper examination of the defect, to determine its most likely origin.

IAL has always been proud to be a one-stop shop for electron microscopy services, consistently offering the high-quality imaging and analysis that is necessary for the failure analysis and intellectual property industries. As the microelectronics industry has evolved, producing smaller, more complex devices, electron microscopy tools have been forced to evolve as well; in keeping with our commitment to providing the highest quality results for our customers, IAL is pleased to announce that we have taken delivery of our new FEI Versa 3D dual beam tool, combining the increased resolution of a field emission electron microscope with the flexibility and added capability of a focused ion beam (FIB) tool. This new acquisition represents an exciting leap forward for our microscopy lab, allowing us to offer several services that previously were out of our reach.

Part of the inherent nature of failure analysis is the fact that no two jobs will ever be quite the same. Failure modes, environmental conditions, device applications – all these parameters shape the circumstances of a given failure analysis project. Managing a failure analysis project therefore requires particular care and attention, to ensure that the proper tools and techniques are chosen for a given job. Charting the course of a failure analysis project requires not only a solid grounding in the tests and equipment used in the lab, but also requires on-the-fly synthesis of disparate data points – not just the incoming data generated by the failure analysts, but also information about how and under what conditions a device was used before its failure.

Every morning in the failure analysis lab holds the potential for a new challenge. A board from a missile guidance system, an integrated circuit from the latest cell phone or video game console, or pieces of a high tech neural implant may be but a few of the many different devices that analysts may find waiting on their desks in the morning (after, of course, a requisite stop at the coffee pot – like many other engineering fields, xanthic alkaloids are one of the cornerstones of a healthy analyst’s diet). Though there is a vast range of device types that may cross an electronic failure (FA) analyst’s desk, there are similarities between every FA project that can be examined; regardless of the unique circumstances of a given electronic device, there are still a handful of standard steps that come together to make up a typical day in the electronic failure analysis lab.

  In many cases, it is necessary to isolate a single defect amidst a vast array of circuitry, singling out a single leaky gate or overdriven transistor from among billions, in order to perform a successful failure analysis. Without some visual way to pluck the single defective device out from the lineup of identical looking circuit elements, an analyst cannot properly target the more destructive steps in the analysis, like cross-section or deprocessing. While some tools, like thermal imaging or other heat-sensitive techniques, can be successful in isolating an area for further investigation, in some cases they aren’t enough; the defect may not be generating enough heat to be detected. In these cases, a different approach, in which one takes the time to understand a device more completely by contrasting some sort of characteristic signature of malfunctioning devices against those that are properly functioning, may be able to isolate the failure. Emission microscopy is one such method of characterizing devices, and offers an excellent picture of many different types of failure upon which to build an analysis.

In part one of this series of tips for outsourcing or hiring an electronics failure analysis service, we examined the wide variety of information that should be gathered before sending a failing part out for analysis. The construction of a detailed packet of data, including a problem description, a background or history of the failing device, and any auxiliary documents like layouts or schematics that may be necessary in chasing down the root cause of failure of a device is an involved process - but, once such a dataset has been assembled, the struggles of choosing a lab to entrust it with can begin in earnest. Just as one would not want to drop an expensive supercar off with any random shadetree mechanic, a one-of-a-kind failure should be sent to a lab with the  best (and most relevant) capabilities, experience, and a proven track record, in order to help ensure the best results.

Electronic component distributors are faced with a myriad variety of risks when dealing with the vast array of devices available on the contemporary market. The looming specter of counterfeit or fraudulent devices, combined with the expected stresses of dealing with run-of-the-mill complaints and RMAs, can be an overwhelming combination of potential problems that must be overcome. In order to surmount these obstacles, diligent distributors must often enlist outside assistance. Fortunately, electronic component failure analysis labs are perfectly poised to help these suppliers struggle through any quality issues they may face.

Non-destructive testing provides the foundation for any thorough failure analysis project. Without properly gathering initial data about the part - condition of the package and leads, electrical behavior, and so on - an analyst would be hard pressed to identify and track down a defect. Often, the use of acoustic microscopy for electronics component inspection can provide invaluable data about the condition of a part that directly leads to identifying the root cause of failure - for example, delamination of the package over the lead for an open-circuited signal. Looking for delamination is only one of the acoustic microscope's applications, however; properly applied, it can reveal much more.

The culminating point of any semiconductor failure analysis job is the task of deprocessing the integrated circuit: removing the various layers of metal and oxide that make up a device until a defect or damage site is revealed. While, in theory, deprocessing seems straightforward, there are many potential pitfalls and nuances that must be accounted for; as such, IC failure analysis companies who can successfully offer IC deprocessing services on a wide range of parts are few and far between. Successful results hinge upon correctly identifying a process type and matching it with the proper set of techniques from an IC failure analysis engineers a comprehensive set of tools.

Historically, the role of IC failure analysis labs has been fairly narrowly defined. A failing device is submitted for analysis (either to an internal or external FA lab), where it is torn apart and subjected to countless different tests before the root cause of failure is finally determined, with analysts trained to distinguish between failures due to manufacturing defects and unintentional overstress induced in a customer’s application (among other typical causes of failure). As the microelectronics market has expanded and evolved, however, failure analysts find themselves faced with another potential source of problems: devices that claim to be something that they are not.

In the blink of an eye, modern electronics systems can sample sensors, perform countless computations, and drive dazzling displays. The sheer amount of data a single system can generate and process is staggering. All this microcomputing muscle would be for naught, however, without a way to store data. Memory is one of the core components of almost any system, from a simple RFID tag to the most powerful processing behemoth. While electronic memories can certainly store and accurately recall more detail than the notoriously malleable human mind, they are by no means immune to failure. Since many modern memories have upwards of 4 billion "bits" of potential data that may be malfunctioning, it is often necessary to enlist outside help in the form of failure analysis services to get to the root of a case of silicon paramnesia.

The printed circuit board is one of the cornerstones of modern electronics technology. The sheer amount of devices and necessary interconnects to interlink them required for even relatively simple consumer electronics cannot be realized without modern high-density circuit board technology. Naturally, this increased level of complexity poses unique challenges for failure analysis; finding an open trace, for example, may require hours of painstaking work poring over board layouts, performing countless microsurgeries on the board to finally isolate the failing node. Even then, once the failure has been isolated through extensive printed circuit board testing, an analyst's tribulations are not finished, as they must then find a way to unearth the buried failure.

Though electron microscopy is an invaluable tool for electronic failure analysis, it has limitations that must be accounted for in the failure analysis lab. Learn more.

To someone unfamiliar with failure analysis of integrated circuits, it can be extremely difficult to imagine how any sort of meaningful data can be produced from a non-functioning piece of electronics – especially when the problem description is often phrased in nebulous terms, sprinkled heavily with empty words like “broken” and “defective”.  Yet, in many cases, a good analyst can turn these imprecise terms into a finely honed insight into a particular defect or device. One may ask how this is possible, given the extreme complexity of modern semiconductor devices. In IAL’s case, the answer lies in a well-planned IC failure analysis lab flow that takes a device from initial observations to final reporting.

Generally speaking, most discussion of electronics failure analysis is geared towards finding silicon-based integrated circuit defects. The reason for this is fairly straightforward; silicon is, by far, the most prevalent semiconductor used to create modern electronics, and therefore has the lion’s share of defects associated with it. In some cases, however, silicon circuits are simply insufficient for a given application – especially when extremely high frequency applications are considered. In these cases, it is much more common to use a III-V semiconductor like gallium arsenide (usually referred to as GaAs). Though the high frequency performance of III-V devices may be much greater than their silicon counterparts, their unique construction poses some difficult challenges for a failure analyst hoping to dig into their inner workings.

PCB failure analysis can be a daunting task in even the most ideal of cases. Modern printed circuit boards are densely-packed, multilayer rat’s nests of copper interconnects, integrated circuits, and discrete components. Isolating a single defect - which may often be a single splash of solder, misregistered via, or cracked copper trace - is an arduous process, requiring hours of probing and isolation to finally narrow down the point of failure. This process is taxing, to say the least; however, the problem is often compounded when the device to be analyzed is no more than a twisted, blackened hunk of burnt PCB material.

One of the most pivotal points of any IC failure analysis is the process of electrical characterization. In order to correctly understand a failure and choose the proper course of action to find its root cause, it is vital to understand the failure’s electrical signature; for example, analysis of a short circuit will follow a far different path than an FA targeting an open circuit. Since it is is so crucial to properly understand the electrical characteristics of a failure, a good FA lab will have a comprehensive semiconductor test program in place that can handle a wide variety of devices.

One of the most critical points of any failure analysis is the decapsulation step. Decapsulation is the point where non-destructive analysis ends and more risky operations begin – the die is removed from its protective plastic shell to allow failure analyst access to the complex circuitry within. Usually, decapsulation is performed using wet-etch procedures, dissolving the plastic encapsulant material of an IC package with any of a variety of different acids or solvents. The downside of this approach, of course, is that working with these potentially hazardous chemicals necessitates some serious safety measures like fume hoods and other types of personal protective equipment. Furthermore, the chemicals most often used for decapsulation, though relatively common, are still not cheap and can amount to a significant expense depending on the number and type of parts that must be decapsulated. Most importantly, the chemical decapsulation process can often disrupt the failure on the part; in some cases, like when working with GaAs or some other III-V semiconductors, the decapsulation chemicals can even dissolve the integrated circuit completely! Fortunately, there is an experimental alternative to chemical decapsulation: laser decapsulation is one of the most promising new technologies on the horizon.

One of the most powerful tools at a failure analyst’s disposal for non-destructively studying the integrity of a component’s packaging is scanning acoustic microscopy. By using ultrasonic waves, the scanning acoustic microscope can detect cracks, air gaps, or delamination with relative ease. There is one caveat to the results from scanning acoustic microscopy, however; in many cases, seeing is believing, and an acoustic image does not necessarily quench the burning desire to view the defect directly. Many manufacturers requesting acoustic imaging services may call the results of a test into question (especially if the result is not one they find favorable); in these cases, it may be necessary to provide another, more tangible piece of evidence.

Oftentimes, discussion of failure analysis services for semiconductor devices tends to focus on the most complex of devices – microprocessors with millions of transistors, intricately designed printed circuit boards, or the fantastically precise silicon sensors called MEMS (micro-electro-mechanical systems). The reality of the industry, however, is that the vast majority of electronic components are far more simple, running the gamut from passive discretes like resistors and capacitors to simple active components like light-emitting diodes (LEDs) and power transistors. Almost every television remote control system, for example, uses a combination of LEDs and photodetectors to allow a user to channel surf. Despite their relative ubiquity, these types of components are just as susceptible to failure as any other – and, therefore, failure analysis can be just as useful in their improvement.

The failure analysis blog we run at IAL has been up for a little over a year now, during which time we’ve covered a handful of different topics pertaining to the services we offer and how we can be of benefit to our customers. We’ve striven to provide a no-nonsense, plain English description of what failure analysis is, as well as straightforward explanations of our equipment – how it works, what it is best suited for, and what its limitations may be. In doing so, we hope to make the general operation of our lab accessible to the widest audience possible, from the most experienced engineer to someone who may only have a passing interest in electronics FA.

Like any problem-solving endeavor, failure analysis can often be stopped cold by a seemingly insurmountable obstacle; electrical isolation techniques fail, deprocessing proves too challenging, or (worst of all) the failure mode simply disappears, vanishing into thin air like a magician’s cheap parlor trick. Any of these situations will give the dreaded result of “No Fault Found”, which essentially means that no valuable information was gleaned from the analysis. Encountering a stymie like one of these in the course of an analysis can elicit wailing and gnashing of teeth from even the most intrepid engineers; at times like these, it is often necessary to enlist the help of external failure analysis services to provide a fresh look at the problem.

One of the fundamental truths of electronics is thus: all devices generate heat to some degree. Some heat emitted by devices is normal – after all, millions of transistors, switching off and on millions of times a second, will consume sizeable amounts of power and therefore produce a considerable amount of heat. However, there are certain types of defects that increase power consumption, thereby increasing the amount of heat given off by a device. While this additional heat is immaterial to the engineering team responsible for the design and production of a device, it can provide a useful avenue for isolating the item that they’re truly interested in – the defect itself. Using thermal emission microscopy, slight differences in temperature can be turned into useful data about a device, enabling a failure analyst to drive to the heart of a defect and determine the root cause of failure.

The modern printed circuit board is a veritable labyrinth of components, vias, and conductive traces, routing electrical signals from point to point through convoluted pathways that span large areas of onboard real estate. While electrical signals have no problem navigating this maze of circuitry, the human eye cannot always follow the same route as traces dive into buried layers deep within the board. Naturally, this greatly increases the difficulty for an analyst tasked with performing PCB failure analysis. Though the unassisted eye may not always be able to detect an issue on a PCB, an analyst has access to many different tools and techniques that can allow the analyst to “see” the defect. As shown in the following two case studies in which both samples were reported as failing for shorts, these tools can be invaluable to a successful analysis.

In an attempt to minimize the ecological impact of the increasing amounts of “e-waste” generated as electronic devices reach the end of their lifespan and are shipped off to the great scrapyard in the sky, the European Union passed the Restriction on Harmful Substances (RoHS) directive. This directive is an edict prohibiting the use of a handful of different materials in any electronic devices manufactured after a certain date (with some exceptions allowed for some applications like medical devices). While it is relatively easy for a manufacturer to guarantee that their own process is free of these elements, given that relatively few manufacturers are vertically integrated, it is often necessary to qualify parts that have been received from various subcontractors and suppliers in order to achieve RoHS certification for a device.

The task of producing high-quality, reliable printed circuit boards have become increasingly difficult as the demands of modern technology have expanded. Even in the time frame of a few years, the inexorable march of technological advancement has demanded the construction of more and more complex circuits, oftentimes with far more stringent requirements placed on parameters like board size and power consumption. Inevitably, increased complexity leads to an increased potential for failure; it is, therefore, more crucial than ever to be able to continually identify and remedy process weaknesses in order to produce the highest number of functioning devices. Fortunately, there are several printed circuit board tests that can be used to examine the quality of a product.

A well-equipped, fully staffed failure analysis lab is a veritable wellspring of knowledge about integrated circuits, semiconductors, and microelectronics in general. With the wide breadth of experience gleaned from years of working with microelectronics, such a lab can take on even the most complex defects and find the root cause of the problem. The skills and expertise honed through the failure analysis process can be applied to other aspects of the electronics industry as well. For this reason, a failure analysis lab may also offer a variety of other support services for the semiconductor industry.

Though failure analysis is an integral part of continually improving a process or product, for many companies it is not feasible to build an internal FA lab. The price of maintaining a wide range of equipment and retaining staff with the diverse sets of skills necessary to perform a successful analysis can be daunting; further, since the FA lab does not directly produce a product, it can often be difficult to justify its existence in terms of number of units sold or amount of revenue generated. Be that as it may, however, failure analysis is still an invaluable contribution to the efforts of such a company to create the absolute best product that they can. In such situations, finding an external lab providing failure analysis services is often the best course of action.

As mentioned in a previous article, the failure mode of an integrated circuit can, in the hands of a trained analyst, be pivotal in determining the course of analysis and successfully isolating a defect. Without understanding how a device malfunctions, it is nearly impossible to determine why – unless, of course, an analyst is blessed with an abundance of luck and a dearth of caution. For those who are not so happily gifted, a well-identified failure mode can save hours of time that would otherwise be spent digging through datalogs and schematics, hunched over a workbench illuminated by the faint green light of test equipment, hunting for any possible toehold to begin the analysis. While it is true that failure modes can be as unique and varied as the endless menagerie of integrated circuits they occur on, there are a handful of usual suspects that an analyst will see time and again over the course of their career.

Considering the relative ubiquity of printed circuit boards in modern electronics, a typical failure analysis engineer will undoubtedly see countless numbers of printed circuit board failures over the course of his or her career. At first blush, many of these jobs may seem to have very little in common – a twisted, charred circuit board from the onboard computer of a river ferry and a defective video game console could hardly be more dissimilar. While it is true that no two failure analysis jobs are alike, and that all defects have subtle nuances that make them unique, PCB failures can generally be broken down into two categories: those occurring during the manufacturing process, and those that occur after the unit has been delivered to the end user.

One of the single most common failures that plague modern electronic devices is current leakage. This leakage can manifest in many ways; some devices may exhibit normal functionality with excessive power consumption, while others may stop working altogether. This is partly due to the multitude of different causes for current leakage – improper processing, packaging, or handling (in the form of electrostatic discharge damage) can result in defects that will draw excessive current, as can electrical overstress of a device in the field. Since current leakage is such a common failure mode, a good failure analyst will have many different tools to assist in the detection and isolation of defects that may cause an anomalous current draw.

The world of electronics grows and evolves at a breakneck pace. On a seemingly daily basis, new electronic gadgets hit the market – the tech-savvy consumer is inundated with choices for faster home computers, powerful smartphones, and more visually stunning TVs; these examples only scratch the surface of the ever-changing landscape of electronic devices. This process of continual growth and discovery seems clearly beneficial for all; there is, however, an unspoken corollary to the unfettered progress made in electronics: the specter of obsolescence looms large, relegating the old, broken, and tragically untrendy devices to the wastebasket. As electronics have become cheaper and more commonplace, the amount of electronics waste in landfills around the world grows at a seemingly exponential rate. To limit the ecological impact of the growing problem of “e-waste”, the European Union created the Restriction on Harmful Substances (RoHS) directive, establishing limits on the amounts of the most ecologically dangerous materials commonly used in electronics. Manufacturers who choose to “go green” take this directive to heart; however, given the complex supply chain involved in most modern manufacturing, it is sometimes difficult to ensure that all components of a device meet RoHS requirements. In these situations, RoHS auditing can…

While many different tools and techniques are used in performing failure analysis and assembling a report, the crux of the analysis is a clear, sharp photograph of the defect that lies at the root of the failure. Indeed, not only in failure analysis but in any of the sciences, it can be said that "seeing is believing": a detailed picture can remove any shadow of a doubt as to the nature of an object. In the case of failure analysis, a good image can help to identify the type of corrective action that must be implemented to resolve a recurring problem. For larger defects, an image taken with an optical microscope is often sufficient; however, given the infinitesimally small geometries used in modern semiconductors, a defect that may be catastrophically huge in terms of circuit performance may still be so small that it is effectively invisible to a traditional microscope - some defects are so minuscule, it is physically impossible to image them accurately with any sort of visible light optics. In these cases, electron microscopy is more than capable of peeling away the cloak of invisibility enshrouding a defect, providing crisp, detailed images at magnifications far beyond the limits…

The ability to isolate a defect in a sea of circuitry, pinpointing a problem hiding amongst a plethora of transistors and metal lines, is one of the cornerstones of successful failure analysis. An analyst would be hard-pressed to study an anomaly in depth without first knowing where the anomaly is. The resourceful analyst has many tools and techniques to aid in the detection of defects on an integrated circuit; some, like liquid crystal or thermal imaging, are best used to find short circuits that generate large quantities of heat, while others, like time domain reflectometry, are best suited to finding open circuits. Unfortunately, these techniques are often not sufficient, and an analyst must find a way to characterize a device, creating a baseline against which to contrast a failing unit in order to detect the defect at the root of an electronic component failure. In these cases, emission microscopy provides the perfect platform upon which to build an analysis.

Since the demonstration of the first integrated circuit in the late 1950s, semiconductor technology has developed explosively, growing at an exponential rate. The guidance computers that were used in the Apollo space program, performing the critical calculations necessary to land a manned spacecraft on the moon, have been completely dwarfed in complexity, memory capacity, and processing power by modern video game consoles and handheld MP3 players. Where an early microchip might contain several hundred devices, today's IC is home to billions of transistors. Even though semiconductor technology has come so far from its inception, it is not yet infallible, and failures do occur as a result of improper processing, misuse, or simply due to the inexorable march of time. Finding a defect on such a complex device may bring to mind clichéd sayings about needles and haystacks; however, the process of semiconductor failure analysis brings together a comprehensive toolset, a breadth of industry experience, and a certain degree of intuition, all in order to find that one in a billion defect.

Electronics failure analysis is, at times, a daunting task. An analyst must constantly question his or her assumptions about a given device, circuit, or process, discarding false premises and peeling away the myriad layers of a problem until the root cause of the failure can be determined. Sometimes, one of the steps in this grand inquisition is to question the fundamental composition and purity of a material. Could ionic contamination be causing a short circuit? Was residual material, left behind on an improperly cleaned printed circuit board, the underlying cause for a solder joint failure? Fortunately, the analyst has tools to analyze materials, even down to their elemental makeup. Auger spectroscopy failure analysis is one of several such tools that an analyst might choose in such a case.

Scanning Acoustic Microscopy (SAM) is a fast, non-destructive investigative technique frequently used in electronic failure analysis. SAM uses ultrasound waves to image interfaces and detect possible defects within optically opaque structures and components such as chip capacitors, chip resistors, circuit board traces, discrete semiconductor devices, integrated circuits (ICs), and other electronic components. SAM is frequently used in failure analysis to evaluate die attach integrity, heat spreader adhesion, and solder quality.

This post explains how to use the Fault Tree Analysis (FTA) technique in integrated circuit failure analysis to find out the root causes of an error in an electronic circuit or component.

Detecting and isolating a failure in an integrated circuit is no easy matter. There are many techniques used in failure analysis and choosing the right one is an art as well as a science. Sometimes we may need to use many techniques both for better detection as well as independent corroboration so that we can be sure of the results of a particular test. But all tests fall into one of two categories - destructive testing, and non-destructive testing. In this article, we look at why non-destructive testing is so important and what methods fall into this type of test.