ACT Educational Series #5 – January 2018
The Power of SEM Analysis
Analysis of an EEE component via a scanning electron microscope (SEM) is a truly enlightening process that may reveal things which might go undetected with less powerful equipment. By magnifying up to 250,000 times and providing a greater depth of field, a SEM can help a trained specialist uncover the telltale signs of a counterfeit part or gain insight into if and possibly why a device may have failed.
Here’s how it works. A scanning electron microscope produces images by scanning the surface with a focused beam of electrons (as opposed to light) emitted through a gun and through a series of electromagnetic lenses in the SEM column. These electrons interact with atoms in the sample, producing various signals containing information about surface and composition. The incident electron beam is scanned in a raster pattern across the surface to create an image. By synchronizing the position in the image scan to that of the scan of the incident electron beam, the display represents the surface area’s morphology.
SEM analysis is a destructive test because of the potential damage to the sample as a result of decapsulation, electron beams, and (where applicable) sputter coating. As a result, SEM analysis is generally performed only in select circumstances—and after most other tests and inspections are performed.
When to Consider SEM Analysis:
- Mandated by or assists with conformance to flowdown requirements or to an industry standard such as SAE AS6171
- Failure within the final product or system is likely result in loss of life, severe injury or major property damage
- Untraceable to OEM and supplier did not comply with AS6081 during sourcing or has recent problem reports against it
Those who attempt to pass off parts as something they’re not, either as new or as a different part number, are increasingly crafty. In response more sophisticated methods are becoming increasingly essential to providing solid assurances that a part without a manufacturer’s certificate of compliance is truly new and authentic. SEM analysis is one of the best tools in the industry’s toolbox to reveal anomalies that may lead to a suspect counterfeit classification.
By inspecting the surface of a semiconductor via a SEM, surface abnormalities and modifications that might otherwise go undetected may be discovered. Zooming in closer than possible with other methods enables technicians to, for example, see contrasts between textures that may indicate a coating was applied OR identify overspills on molds as a sign that the device was blacktopped. SEM analysis can also document contrasts in laser patterns around part markings as evidence that a sample was laser etched. Surface abrasions and sanding marks may also be discovered.
As the chips used within semiconductors become more miniaturized and complex, the causes of EC failures become more diverse and complicated. Failure analysis, for which SEM analysis can be integral, may lead to the identification of a device as the cause of failure and/or reveal the reason why a particular device failed to perform as expected. This information can be used to improve design, increase production yield, and minimize returns or repairs.
During SEM analysis, a device may be delidded and the metallization of the die inspected to search for imperfections or burn marks that might affect how a part operates. Technicians may also inspect the bonding, including where the bond attaches to the die, to confirm whether or not all the joints are clean.
At Advanced Component Testing, we can perform sophisticated SEM analysis via a Hitachi SEM. Our in-house staff can use this powerful microscope to inspect the surface for signs of adulteration during counterfeit testing or, as part of failure analysis, to check metallization and attachments for anomalies including scratches, cracks, voids and burn marks created by prior use or during the manufacturing process.
ACT Educational Series #4 – September 2017
Up-Screening Issues & Tips
It happens, especially when you’re working with older parts. When you just can’t find an electronic component with the right manufacturer specs to do the job, either at all or at anything but an exorbitant price, then it’s time to consider up-screening parts you either have in stock or can purchase. “Up-screening” is testing for the purpose of documenting device performance to higher specs, including wider temperature ranges, as compared to original manufacturer drawings. Up-screening is made possible by the fact that semiconductors and other active and passive components can often operate above and beyond at least some of their official specifications.
Common scenarios in which up-screening may contribute to a viable solution include:.
- An obsolete component that is no longer available is required to maintain, repair or produce a legacy part or system and thus you seek to substitute another part.
- A customer is looking for a military or industrial version of a COTS item so you need to enhance performance or environmental tolerance.
- Part selection to weed out marginal product via burn-in to help ensure reliability.
- To address a design issue in which a part needs to perform at a higher level or withstand a higher stress level and thus needs to meet higher specs or be replaced.
ACT can test and characterize EEE parts including passives, logic, analog and discrete devices to a source control drawing or to comply with other (for example, military) specifications. Parameters to which ACT engineers and technicians can perform up-screen testing include: temperature, voltage, current, timing and frequency.
Before you embark on an up-screening project, here are a few suggestions from the staff at ACT:
- Prior to buying a large stock of parts that you hope to up-screen or perform part selection on, consider testing a small sample to gauge whether or not you’re likely to achieve the desired outcome.
- If you need assurance that a device can operate reliably at a higher or lower temperature, then keep in mind that temperature can affect device speeds and voltage levels. To avoid problems, we advise additional testing of all parameters that may be affected.
- Although authentic new parts should perform to manufacturer specs every time, these same parts may outperform these specifications to varying degrees and thus may not consistently reach the level desired. The smart move is to plan for some fall out.
- Before embarking on burn-in or other stress testing, you might want to confirm that any anticipated reduction in lifespan is acceptable.
SAE Releases Sister Standard to AS6081 for Labs: AS6171 – March 2017
ACT is One of Few Facilities that Can Comply
The fact that counterfeit EEE parts are in the supply chain, and may be unwittingly purchased by those requiring components that are unavailable through direct or franchised channels, has been a known issue for over a decade. During this time, counterfeiters keep finding new ways to make and profit from seemingly authentic parts that are refurbished, mislabeled, substandard and/or non-functional.
In order to mitigate the numerous costs and even potentially catastrophic risks associated with counterfeit electronic components, industry organizations and U.S. agencies have been developing standards that various supply chain actors can (and in many cases, must) comply with in an effort to weed out counterfeit parts and improve the overall integrity of the supply chain. As the problem continues to evolve, so do the standards in the form of sporadic revisions and altogether new standards that provide increasing granular detail with respect to requirements and test methods.
SAE international released its latest standard, AS6171, in late 2016. A few AS6171 highlights include:
- For use in aviation, space, defense and other high performance applications when parts lack traceability to an OCM or OEM
- Specifies testing as per acceptable risk levels to identify anomalies or performance issues that may indicate parts are counterfeit
- Specifies detailed test methods that must be performed by a responsible laboratory that is accredited to ISO 17025 for the tests executed (ACT is compliant for AS6171 testing)
- .The counterpart to AS6081 (for distributors) and AS5553 (for manufacturers); with similar, complementary requirements and detailed methods
- Visit the SAE landing page on AS6171 for more information
If you are a supplier to the aerospace industry and you possess, or are purchasing, a EEE part for an aerospace application lacking full traceability than you may want (or need) to adhere to AS 6171 in order to either meet flowdown requirements or simply to take maximum precautions against the use of a substandard component within an aerospace assembly or system. After all, counterfeiters are getting more sophisticated in their techniques every year. With that in mind, it seems prudent for those who buy or utilize electronic components to adopt the latest and greatest safeguards against potentially substandard inauthentic devices
ACT Educational Series #3 – August 2016
What Makes Op Amp Testing So Challenging
Operational amplifiers are a key building block used by engineers to develop analog circuits and are thus one of the most widely used electronic devices today. Unfortunately these little workhorses have a propensity to oscillate and their testing entails minute measurement, which means that one has to get creative in order to produce accurate results. The staff at ACT has significant expertise dealing with analog phenomena and, over the last year, has developed a variety of field proven methods:
- By their very nature, op amps (which are differential amplifiers) have very high gain and tend to oscillate. Because of this they must be stabilized before precise measurements can be taken. ACT has perfected compensation techniques that operate into the hundreds of MHz range.
- When input bias currents are small (as is the case with most newer op amps) additional complications arise. Small currents are tested with large precision resistors, making the circuitry far more susceptible to noise and stray EM fields. ACT addresses this issue through guard banding, Faraday shielding, and/or battery powering circuitry.
- Low noise op amps present another challenge. When noise measurements are required on these: low-noise, battery-powered, shielded fixtures are a must.
Given all these challenges, competency with analog technology should really be considered a mandatory requirement for any test house performing op amp testing. ACT has the experience as well as the fixturization to successfully evaluate op amps.
ACT Educational Series #2 – February 2016
Manual vs. Automated Testing
There are two basic approaches to performing electrical tests: manual and automated. ACT offers both types of testing and would like to explain and compare them to help you understand the difference.
Manual testing involves the development of specific test circuits and the use of electronic bench equipment in its execution. It is a labor intensive methodology that begins with the development of a test procedure, which is followed by an operator who performs the test manually.
Despite this limitation, manual testing is generally mandated by special test conditions. For example, a special PCB would need to be developed in order to test high speed digital devices where transition times are in the sub nanosecond range. Other drivers would be high current, high voltage or high resistance, as these characteristics are typically beyond the normal capabilities of generalized testers.
Automatic testing, on the other hand, is implemented by running a part-specific algorithm on a general purpose test fixture. The algorithm is basically the equivalent of a test procedure used in manual testing. The benefits of automatic testing are that (1) Execution is much faster, reducing labor costs and (2) The test is always done exactly the same way.
Automated testing is generally used for testing larger quantities of parts. The cost tradeoff is between estimating the cost to create a procedure and manually test versus the cost to develop a test algorithm and run on a machine. Manual testing is executed by highly trained personnel at significant expense. Automated testing begins with highly trained personnel developing the algorithm, which is run by lab technicians at a lower labor rate.
Advanced Component Testing offers automated testing (including parametric, functional, burn-in, up screening, binning and more) as well as manual testing to both AC and DC characteristics. Read more about electrical testing with ACT.
Avoid Paying for Subpar Testing
For a while, Advanced Component Testing (ACT) has been hearing from some of our customers about their paying for component testing only to realize, after the fact, that the testing failed to meet their actual requirements. As one of a handful of trusted test labs for some of the most discerning organizations, recently recertified to ISO 17025, ACT would like to offer you insight into the problem and a few tips on how to avoid finding yourself in this precarious situation.
The Problem: You request a quote for electrical testing and receive one from a test house that appears to meet your specifications. Unfortunately you don’t realize that the testing quoted does not rise to the level of your requirements—and may even have little value as an electrical test, such as inappropriate use of go/no-go results.
The Consequences: Once you realize that the electrical testing was inadequate you will most likely need to resume the process to secure proper testing. Of course, in the meantime you might miss key in-house and customer deadlines. Not to mention the wasted money spent on the subpar testing. But that’s only if you catch it, otherwise the part could end up in a product or system and could cause premature and even catastrophic failure.
Possible Warning Signs:
- Lab neglects to ask for specifics on an RFQ that uses general terms.
- Temptingly low estimate, especially as compared to prices quoted by other labs.
- Quote uses different or vague terminology to describe tests, as compared to the RFQ.
- Footnotes and other fine print that might indicate an inferior level of testing.
How to Avoid Falling Prey
- Submit RFQs with detailed language spelling out testing needs including flow-down requirements, where applicable.
- Ask your lead project engineer or quality manager to review quotes to verify that the testing quoted will actually satisfy all requirements.
The most reputable of test labs—those that deserve your trust—asks questions to ensure that all test requirements are fully and correctly defined before submitting a quote. They may even make suggestions to better ensure that your testing goals and flow-down requirements will be fully met by the proposed testing. They may not always be cheaper in the short term but, in the long run, using such a lab will pay dividends.
ACT Educational Series #1 – December 2015
Three Electrical Test Types
Sy Syms, founder of the now defunct off-price clothing chain, famously coined the slogan “An Educated Consumer is our Best Customer.” We at Advanced Component Testing also ascribe to that philosophy and, in that spirit, we’d like to begin sharing even more to help you understand electrical testing of electronic components.
Let us start by comparing three main types of electrical testing that are often confused with each other.
- Electrical Curve Tracing is a simple test of each pin to evaluate PN junctions, shorts and open circuits, in which findings are matched against manufacturer definitions of input and output types and structures. Curve tracing generates a graphical display of the relationship between two parameters (normally voltage and current) of an electronic component. It is generally considered the most basic electrical test performed for authenticity screening.
- Functional Testing is basic testing to verify whether or not a device performs a particular action or set of actions. It demonstrates the ability of a component or assembly to meet design requirements. Functional tests may require a laboratory, such as ACT, to design unique tests for specific functionality.
- Parametric Testing is detailed electrical testing of a component against parameters specified by the manufacturer or drawing. Common DC parametric tests include voltage levels, thresholds, drive capability, and leakage tests. AC parametric tests may include frequency of operation, delay, setup and hold tests. Advanced Component Testing recently commissioned the Lorlin Double Impact Discrete Component Tester to perform a wide array of automated DC parametric tests on small signal and power semiconductor components.Sy Syms, founder of the now defunct off-price clothing chain, famously coined the slogan “An Educated Consumer is our Best Customer.” We at Advanced Component Testing also ascribe to that philosophy and, in that spirit, we’d like to begin sharing even more to help you understand electrical testing of electronic components.
Please check back occasionally for a continuation of this educational series.
Factors to Consider BEFORE Utilizing Aged Component Inventory – July 2015
Just because it’s in your warehouse or in a box in the back of your engineering lab doesn’t mean an electronic component is suitable for use whenever the need arises. That’s because the longer a component has been in house, the greater the odds that there may be an issue that needs to be addressed before it is used. Ignoring these concerns could result in electronic components that are either substandard or counterfeit making it into the supply chain—and into an end product or system where they may result in product failures and warranty costs.
In contrast, when proper precautions are taken aged inventory can be converted from a costly liability to a valuable asset. Which situation would you rather be in?
Here are the main factors to consider before using an in-stock, legacy electronic component:
Unknown Authenticity: Unless an electronic component has full documentation linking it back to the OCM, there’s a chance it might not be authentic: especially if its acquisition predated your organization’s adoption of a counterfeit mitigation plan. You see, back in the day before the threat posed by counterfeit electronics components was widely recognized; independent distributors did not generally screen parts for quality and authenticity. That means the component sitting on your shelf could be counterfeit or otherwise substandard and the only way to feel confident that is not the case, short of a C of C, is to have it undergo comprehensive component authenticity inspection and testing.
Moisture Permeation: The longer an electronic component sits in a warehouse the greater the odds that it has been compromised by moisture. Even a relatively small amount of moisture can cause a product to fail prematurely and there’s a shelf life to dry packing—and climate controlled warehouses have their limitations. Often the most certain and cost-effective way to ensure that moisture is not a problem is to re-bake-out and dry pack in accordance with IPC/JEDEC J-STD-033B.
Compromised Quality: How do you know for sure that components stored long term at your facility will perform to manufacturer’s specifications? Especially if you suspect they could have been mishandled or unintentionally compromised in some manner. Full parametric electrical testing will validate whether or not a component operates in accordance with published specs. That’s one surefire way to be certain that you’re still dealing with a high quality electronic component.
In the end, after proper precautions are taken, aged inventory can be converted from a costly liability to a valuable asset. And when it comes to sensitive electronic components, isn’t it always best to err on the side of caution?
Rushing to Judgment on these 3 Tests Can Be Misleading – February 2015
When most people think about authenticity testing they think it’s simply a matter of performing a few tests and noting the results. But the reality is that it often goes way beyond that, especially when an anomaly is identified. That’s because the presence of an anomaly does not necessarily signify that a component is substandard or inauthentic. While that may sound counterintuitive at first, it actually makes sense when you consider the complexities of the manufacturing process.
In our experience, three authenticity tests that are most prone to false fails are the XRF material analysis, delidding die analysis and Dynasolve 750 test. Better understanding how these tests are done and the nature of the findings will make you a more informed customer—and that’s good for everyone. So please read on… and feel free to contact an ACT technician or engineer with any questions you may have about these or any other component authenticity test ACT offers.
Extra XRF Analysis
XRF analysis begins with the scanning of leads and/or the package via X-ray fluorescence spectroscopy to identify the elemental composition of materials, the concentration of solids and solutions, and trace elements. This data is then compared to a device’s official data sheet. In many cases the initial findings do not present an exact match; especially when it comes to the presence of lead. If lead is detected within a device’s plating, that a spec sheet states should be lead-free, then ACT will investigate to see if a valid justification exists. For example, the device may have actually been lead dipped for a particular military application, which is denoted by some obscure mark on the device. If the intended use is military, and RoHS compliance is not mandated, then this intentional deviation may be completely acceptable and even desirable.
In another scenario, a trace of carbon may be detected on the leads. The next logical step is for ACT to investigate the plating and methods that may have been used in the retinning process to see if this may have caused the carbon trace. This may require contact with the OEM and may transform what would have been a 5-minute test into one that takes several hours or more.
Solving the Dynasolve 750
With the Dynasolve 750 test, ACT submerges a device in the solvent for 45 minutes and then swabs it to observe for evidence of resurfacing under a microscope. It is not unusual for thermal coating to be found on a device but ACT does not automatically record this as a fail, although that certainly would speed up the process. Instead our next step is to investigate to see if the thermal coating may have been applied by the manufacturer during a certain time period that can be linked to the date code that we interpret from the part marking. This may require getting information and documentation directly from the manufacturer, which can take days.
Delidding Detective Work
When a device is delidded for internal inspection, ACT checks that the external and internal part markings are consistent. Unfortunately, it is not uncommon for the two to differ. When this happens, instead of simply indicating a fail for the test, ACT must research the device further. Two common scenarios are when a manufacturer is fabless or when a manufacturer enters into a joint venture with another company to provide the die on a specific line. The only way to know this is to research the device and its production schedule to see if they can explain the apparent anomaly and then confirm that via the date code that can be extrapolated from the part markings.
When it comes to counterfeit testing, initial observations and findings often require additional research and interpretation before they can be reliably reported. The period of time this may take is not always predictable and this can occasionally delay results but, as you can see, there are times it is unavoidable—for accuracy sake.
Government QTSL Mandate & ACT Compliance – August 2014
A few weeks ago, the DLA Land and Maritime contacted QTSL suppliers with a reminder about the minimum requirements to which components covered by the program must adhere. They noted that “all electrical tests are required to have full read and record electrical test results performed and included with all QTSL test reports.” Rest assured that all past and future price quotes from Advanced Component Testing meet these standards and all outstanding quotes will be honored by ACT. But with other labs that’s not always the case.
So the next time you get a lowball quote, look closely to see exactly what’s included… because as a QTSL supplier your company is responsible for ensuring component quality. And make sure you get it in writing.
As far as ACT goes, Advanced Component Testing performs all applicable tests and inspections strictly to AS6081 standards. The exception is with customers specifying a lesser testing standard for commercial parts with no connection to the DLA. We can accommodate those orders too.
So remember: Sometimes when it sounds too good to be true it’s because it IS too good to be true.
Anything Less than Full CAIR Can be Risky – July 2014
At Advanced Component Testing, we believe that performing the complete component authenticity inspection report (CAIR) is almost always the right way to go because each step is invaluable to identifying component inconsistencies and defects.
HERE’S HOW IT WORKS: Visual inspections allow us to locate obvious defects and inconsistencies between components of the same lot or date code. Much like an airline pilot performing a pre-flight walk around, we’re making sure to notice anything out of the ordinary. But that alone certainly doesn’t validate authenticity.
XRF spectrum analysis is another tool offering clues to a component’s origins. If the material composition does not match what the manufacturer indicates, suspicions are raised and we have yet another path to follow. Mechanical de-lidding and chemical decapsulation are vital methods for confirming physical consistency. Again, counterfeiting techniques are quite advanced and the components may perform electrically and pass all marking permanency tests; but removing the cover and exposing the die will let us visually confirm that the heart of the device originated at the correct manufacturer’s facility. Couple that with X-rays to match the layout and configuration of the internals and we can conclude with relative certainty whether or not a device is authentic.
So don’t shortchange yourself by running only a few cherry picked tests and rolling the dice. ACT’s entire process is designed to chip away at the various methods counterfeiters use to fool buyers. And isn’t it better to be safe than sorry?