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FEAT


ATURE


COVER STO RY


SEMICONDUCTOR COUNTERFEITING The myths and the methods used to uncover the ths and the methods used to uncover the t ruth


By Ken Greenwood, technical sales manager EMEA, Rochester Electronics By Ken Greenwood, technical sales manager EMEA, and increased rework.


• Increased in-service failures and reduced reliability.


• Heightened risks and financial lia bilit associated with catastrophic system failure.


• Cost of reputational damage.


WHAT DOES “100% TESTED” REALLY MEAN?


Customers may incorrectly assume “T esting” provides a 100 per cent


genuine guarantee. At it s most basic, 3rd party t esting comprises one or some of the following:


C


ounterfeits come in many guises. The most basic definition of a Count erfeit is “an imit ation intended to be passed off fraudulently or deceptively as genuine, for profit.”


In times of supply shortage, or


where component obsolescence limits availability, the prevalence of counterfeitavailability, t devices often multiplies. As awareness increases, so does sophist ication. We have moved far bey ond incorrect manufacturers logos and IC packages with no die inside caught by the simplistic visual inspection t esting used by those following AS6081. The Counterfeiters now have very sophisticated operat iions as the potent gains can be enormous.


ons as the potent ial


Customers whose normal supply routes prove insufficient may assume unauthorised or gray market sources are the only solution; and that “T esting” can eliminate qualit y risks. Nothing could be further from the truth; but there ARE zero-risk sourcing options available.


WHAT IS A COUNTERFEIT SEMICONDUC


WHA SEMICONDUCTOR?


In the Semiconductor world Counterfeit s include:


• Non-Functional or scrap product which is re-marked as good and re-sold. • Functional yet sub-standard product purchased by the count erfeit er remarked and re-sold as full grade product at an increased price.


• Re-cycled and recovered component s re-sold as new.


34 MAY 2020 | ELECTRONICS


In all these cases, the process of et ching back the original ext ernal markings with aggressive chemicals or even mechanical grinders can result in internal bond or substrate damage. Or the chemical residues from the cleaning process, slowly ent er and contaminate the device, causing bond-pad or bond- wire failures in-service.


The process of recovering previously used semiconductors from old PCB’s can also result in catastrophic heat and/ or mechanical damage. Recovery of the IC from the PCB itself is normally t he last step of a long scrap t rail which includes; a previous working life; and a return-for-recovery route through an uncont rolled storage environment. Exposure to excessive humidity, water, and salt is often routine. This process can produce an authentic used product that has questionable reliability. Authent icity does not automatically mean Reliability. Identifiable surplus stock and traceability provides no guarantee regarding the storage conditions encount ered during the components complete shelf- life.


ered during t The


consequences of allowing sub-


standard product to enter the


supply chain may include:


• Reduced product ion y ields / ELECTRONICS


• Paperwork and Visual Inspect ion: Unlikely t o identify the professional counterfeit devices. T raceability documents & certificates are also regularly forged to support the overall deception.


• X-Ray Inspection: Unlikely to identify fraudulently up-screened, well-marked recovered & re-used, or recovered failed- test devices.


Writer Ken Greenwood of Rochester Electronics


• Basic Continuity or Funct ional Testing: Will not identify the fraudulently


• Basic Continuity or Funct


upscreened or well-marked recovered & re-used devices.


• Full Functional Testing: The


datasheet only provides a subset of the characteristics tested by the Original- Chip-Manufacturer (OCM).


S FUNCTIONAL TESTING CARRI ED OUT OVER THE FULL TEMPERATUATU RE RANGE?


IIS F


When functionally t esting a device, FAULT COVERAGE is critical. Without 100 per cent test fault coverage, t he device WILL have residual failures. Residual failures are devices that cont ain faults, but which PASS the testing used.


Example of Basic Functional Testing: Simple Traffic Controller:


LY bilit y


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