This guide covers: the five types of counterfeit components and why visual inspection alone cannot reliably detect them (POINT 01); the five detection methods used by qualified laboratories and incoming inspection teams, and when to apply each (POINT 02); the supply chain prevention measures that address the root causes of counterfeit exposure — not just the symptoms (POINT 03); and the structured response procedure when a counterfeit is confirmed inside your facility (POINT 04).
The term "counterfeit" covers a range of deceptive practices with different physical characteristics, different detection requirements, and different implications for the products they enter. Understanding the specific type of counterfeit you are dealing with is essential to selecting the correct detection method and assessing the likely failure mode in your application.
TYPE 01 — MOST COMMON
Remarked Parts
Used, degraded, or lower-specification components are cleaned, resurfaced to remove original markings, and relabelled with a higher-grade or newer date code. The process frequently involves abrasive polishing or chemical stripping of the original surface followed by laser or inkjet remarking. The internal die is real — it is the marking and condition that are fraudulent. This is the most prevalent counterfeit type and represents the majority of documented counterfeit incidents in the electronics supply chain.
Detection: solvent test (marking dissolves), surface microscopy (polishing marks), X-ray (die matches, but lead oxidation pattern may reveal age)
TYPE 02
Specification-Upmarked Parts
A component from a lower-specification product family — commercial temperature range relabelled as industrial; a 500 MHz device relabelled as 1 GHz; a 40V-rated part relabelled as 100V — is substituted for the genuine article. The internal die may be from the same family and will frequently pass basic functional testing. Failures occur at the edges of the specification — under temperature extremes, at high frequencies, or under sustained voltage stress — often months or years after delivery.
Detection: full electrical characterisation across the specification range (basic functional test may pass); thermal chamber testing at specification limits
TYPE 03
Fully Counterfeit Parts
The package and marking replicate a genuine component, but the internal content is entirely different — a non-functional die, a die from an unrelated component, passive fill material, or in the most extreme cases, an empty package. Fully counterfeit parts fail all functional electrical tests and are typically detected immediately at electrical characterisation. The primary risk is that inadequate incoming inspection allows them to reach the assembly stage, where the failure mode causes significant production disruption.
Detection: electrical characterisation (immediate failure); X-ray (die absent, mismatched, or structurally inconsistent with datasheet)
TYPE 04
Grade-Upmarked Parts
Commercial-grade components (rated for 0°C to 70°C, or 0°C to 85°C operation) are relabelled as industrial-grade (−40°C to 85°C) or automotive-grade (−40°C to 125°C or 150°C). The die may be from the same wafer — the differentiation between grades is often performed by the original manufacturer through selection testing, not by manufacturing different die. A grade-upmarked part will function within the commercial range and fail only when the extended temperature specification is exercised. The failure mechanism is indistinguishable from a genuine part failure without traceability data.
Detection: traceability documentation (lot number cross-check with manufacturer); high-temperature electrical characterisation at automotive/industrial specification limits
TYPE 05
Rejected or Scrap Parts
Components from a manufacturer's out-of-specification reject stream — parts that failed the manufacturer's own production test or quality gate — are diverted back into distribution through unauthorised channels rather than being properly destroyed. These parts carry a genuine manufacturer marking and a real date code; the fraudulent element is that they were quarantined by the manufacturer as non-conforming and should never have entered commerce. Rejected parts are nearly impossible to identify through standard visual or electrical inspection unless the specific failure mode is known.
Detection: traceability cross-check with manufacturer (lot number may appear on scrap or quarantine records); statistical anomalies in electrical characterisation results
⚠ When counterfeit risk is highest: Counterfeit exposure correlates strongly with conditions that push procurement outside of authorised distribution channels. End-of-life (EOL) components where genuine stock is exhausted; components sourced during semiconductor shortage events when authorised distributors are allocated out; and parts procured from unfamiliar brokers without documented traceability are the three highest-risk procurement scenarios. During the semiconductor shortages of 2020–2022, industry bodies including ERAI reported a significant and documented increase in counterfeit incident reports — the correlation between shortage conditions and counterfeit prevalence is not coincidental.
No single detection method identifies all counterfeit types. A layered approach — applying methods in sequence, with each stage informed by the results of the previous one — provides the most reliable coverage. The AS6171 standard defines recommended test methods and sequences for each component type; the methods below follow that framework.
METHOD 01Visual Inspection
The first and most accessible screening method. Performed under magnification (10× loupe as a minimum; 30–100× stereo microscope for detailed examination) on all incoming lots. Evaluate: marking clarity and font consistency (genuine laser markings have sharp, consistent edges; inkjet and chemical etching have characteristic differences); lead plating condition (oxidation, inconsistent plating coverage, evidence of re-plating or abrasive cleaning); package surface condition (polishing marks from remarking operations are visible under raking light); date code and lot number format compliance; and package dimensions and weight relative to the manufacturer's published specification. Visual inspection is effective for catching poorly executed counterfeits and establishing a baseline for all subsequent testing, but professional-grade remarked parts and grade-upmarked parts are frequently indistinguishable from genuine articles by visual inspection alone.
Marking clarityLead platingSurface polish marksDate code formatPackage dimensions
METHOD 02X-Ray Inspection
Non-destructive internal examination of the package to verify the presence and structure of the internal die and lead frame. X-ray images are compared against reference images from the component manufacturer or from previously verified genuine lots. Key findings: fully counterfeit parts with absent, mismatched, or dimensionally inconsistent die; die bond wire configuration inconsistent with the manufacturer's known structure; lead frame construction inconsistent with the manufacturer's package variant. X-ray inspection does not reveal the electrical performance of the die or differentiate between genuine and specification-upmarked or grade-upmarked parts where the die is from the same family. AS6171 includes X-ray inspection as a primary method for IC and semiconductor components. When a qualified X-ray technician identifies an anomaly, the finding should trigger decapsulation of a sample for direct die examination.
Die presenceDie dimensionsBond wire patternLead frame structureNon-destructive
METHOD 03Decapsulation (Die Inspection)
A destructive examination in which the package is opened — chemically, using hot concentrated acid (fuming nitric or sulphuric acid), or mechanically using a precision milling tool — to expose the internal die for direct optical examination. The exposed die is examined for: manufacturer logo or die marking; die dimensions relative to the manufacturer's known specifications; process node characteristics consistent with the claimed product; and any signs of damage, contamination, or non-authentic origin. Decapsulation is applied to a statistical sample from the lot — not to every unit — due to its destructive nature. The sample size required for a given confidence level is defined in AS6171. A decapsulation finding that identifies a non-authentic die is definitive evidence of counterfeiting and triggers immediate lot quarantine.
Die manufacturer markingsDie dimensionsProcess nodeDestructive — sample basis
METHOD 04Electrical Characterisation
Measurement of key electrical parameters specified in the component datasheet — including DC characteristics (VIH, VIL, VOH, VOL, Icc), AC timing parameters, and functional truth tables for digital devices; or key parametric values for analog and power devices (Vth, RDS(on), leakage currents, gain bandwidth). Testing must be performed across the full specification range — including at temperature extremes — to detect grade-upmarked and specification-upmarked components that pass testing at ambient conditions but fail at the specification limits. Electrical characterisation identifies fully counterfeit parts (immediate failure on all tests) and specification-upmarked parts (pass at ambient, fail at extremes). It does not reliably identify remarked parts where the die is genuine, or rejected parts where the specific failure mode is outside the tested parameter set.
Full datasheet coverageTemperature extremesDC + AC parametersFunctional test
METHOD 05Solvent and Environmental Testing
A rapid and low-cost screening method for detecting remarked components. The package surface is wiped with acetone, isopropyl alcohol (IPA), or methyl ethyl ketone (MEK) on a white cloth or cotton swab. Genuine laser-marked or moulded markings are resistant to these solvents. Inkjet, pad-printed, or chemical-etched counterfeit markings applied over the original surface during the remarking process will partially or completely dissolve or transfer to the swab. A positive solvent test result is presumptive evidence of remarking and should trigger immediate escalation to X-ray inspection and decapsulation. AS6171 specifies the solvent sequence and observation criteria. Note that some genuine manufacturer markings — particularly older ink-stamp markings on through-hole components — may show slight solvent sensitivity; interpret results in the context of the specific component type and manufacturer marking method.
Acetone / IPA testMarking transfer on swabLow costRapid screeningRemark indicator
Applying the methods in sequence: For a standard incoming lot from a qualified authorised distributor, visual inspection is typically sufficient as a baseline. For a lot from an independent distributor with full traceability, add electrical characterisation. For a lot where traceability is incomplete, the source is unfamiliar, the component is life-safety-relevant, or the part is an EOL/shortage-period procurement: apply the full sequence — visual, solvent test, X-ray, electrical characterisation, and decapsulation on a sample. Any anomaly at an earlier stage should trigger escalation to the next stage, not a pass decision.
Incoming inspection is a containment measure — it catches counterfeits that have already entered your receiving dock. The prevention measures below address the conditions that allow counterfeits into your supply chain in the first place. The most effective counterfeit prevention programmes operate primarily through procurement controls, not through inspection intensity.
🏆Prioritise Authorised Distribution Channels — As Policy, Not Just Preference
Authorised distributors — those holding a direct franchise agreement with the component manufacturer — source exclusively from the manufacturer or manufacturer-authorised sources. Their counterfeit exposure is structurally near-zero by virtue of their sourcing model. Major global authorised distributors include Digi-Key, Mouser, Arrow, Avnet, and their regional franchised partners. In Japan, established manufacturer-authorised commercial distributors (公認販売代理店) provide equivalent assurance. Formalise this preference as a written policy: define the conditions under which non-authorised sourcing is permissible (EOL, shortage, with management approval and enhanced incoming inspection), and make the default assumption that non-authorised sources require additional scrutiny.
🏅Require AS6081 Certification for Independent Distributors
When sourcing from an independent distributor is unavoidable, confirm that the distributor holds AS6081 certification from an accredited body (SAE International or a nationally accredited certification body). AS6081 defines the management system requirements for independent distributors to avoid, detect, mitigate, and dispose of counterfeit electronic parts. A certified distributor has been audited against these requirements by a third party. AS6081 certification does not guarantee that a specific lot is genuine — it confirms that the distributor has adequate systems in place. Complement it with traceability requirements and incoming inspection appropriate to the specific component and risk level.
📋Require Documented Traceability to the Original Manufacturer
For all lots sourced outside authorised distribution, require: proof of purchase documentation tracing the lot through each point in the distribution chain back to the original component manufacturer; the manufacturer's certificate of conformance for the specific lot, including date code and lot number; and — for life-safety-relevant components — an AS6171-compliant third-party test report from an independent laboratory. If the distributor cannot produce a documented chain of custody that reaches the original manufacturer, the lot has unverifiable provenance. Treat unverifiable provenance as a high-risk indicator and apply comprehensive incoming inspection before any use, or reject the lot.
🔍Standardise Incoming Inspection — Risk-Proportionate, Not Uniform
Apply incoming inspection requirements that are proportionate to the source and application risk, not uniform across all lots. Authorised distributor lots for non-life-safety applications: visual inspection as baseline. Independent distributor lots with full traceability: visual inspection plus electrical characterisation. Incomplete traceability, unfamiliar source, or life-safety application: full AS6171 inspection sequence including X-ray and decapsulation. Document the risk-proportionate inspection matrix and make it a quality procedure — not an ad-hoc decision for each incoming lot.
🔎Conduct Periodic On-Site Supplier Audits
For significant independent distributor relationships, conduct documented on-site audits at a frequency proportionate to the volume and criticality of your sourcing from them. Key audit areas: physical warehouse conditions and segregation of suspect or quarantine stock; incoming inspection processes and equipment; traceability record systems and record retention; quality management system documentation; and evidence of prior counterfeit detection and disposition. Physical audit reveals risk factors that documentation-only review cannot — a warehouse with poor stock segregation, missing chain-of-custody records, or a lack of systematic incoming inspection is a much higher counterfeit risk than its certificates suggest.
⚠ Cost-reduction pressure is the primary driver of counterfeit exposure: The decision to source from an unfamiliar or unverified broker is almost always driven by price — the component is cheaper, or it is the only apparent source during a shortage. The cost comparison that should be made is not unit price versus unit price, but unit price from an unverified source versus the cost of a counterfeit reaching your product: incoming inspection time, production stoppage, field failure investigation, warranty claims, recall costs, and — in life-safety applications — regulatory action. The total cost of a single counterfeit escaping to field service routinely exceeds the aggregate savings from years of cost-optimised sourcing decisions.
If a counterfeit is confirmed — at incoming inspection, during assembly, or in the field — the response must be immediate, systematic, and documented. The speed of the initial containment action determines how much of the affected lot reaches your products and your customers. The following steps should be part of a pre-defined procedure, not improvised under time pressure.
Immediate Quarantine — Full Lot, All Locations
The moment a counterfeit is confirmed or strongly suspected, quarantine the entire affected lot across all locations simultaneously — not just the units on the receiving bench. This includes units in bonded stock, units in WIP, units already assembled into PCBAs, and finished goods that have not yet shipped. Do not allow any further processing of units from the affected lot pending investigation.
Immediate stopAll locationsWIP + finished goods
100% Inspection of the Quarantined Lot
Conduct 100% inspection of all quarantined units using the detection methods appropriate to the counterfeit type confirmed. The objective is to determine whether the contamination is lot-wide or isolated to a portion of the lot — this determination drives the scope of product containment required. Document every inspection result, every unit disposition (destroyed, returned to supplier, held for further testing), and every unit that cannot be accounted for.
Full lot inspectionScope determinationUnit-level documentation
Trace Affected Products and Initiate Containment
Use your traceability records to identify all products that may have incorporated units from the affected lot. This includes PCBAs in WIP, finished goods in inventory, products already shipped to customers, and products in transit. For shipped products: initiate a customer notification and field containment action proportionate to the application risk — a life-safety device requires immediate notification; a non-critical consumer product may allow a more structured response. Document the scope of the containment action and the rationale for the response level selected.
Product traceabilityField containmentCustomer notification
Formal Supplier Claim and Root-Cause Demand
Submit a formal written claim to the supplier with the inspection evidence — photographs, test data, and X-ray or decapsulation reports where available. Demand a root-cause analysis report (8D or equivalent format) with a documented corrective action plan. Preserve all suspect units in documented storage pending supplier response and potential regulatory involvement — do not destroy evidence. The supplier's response to a formal counterfeit claim is itself a qualification data point: a supplier who handles it professionally demonstrates a level of supply chain integrity that a supplier who denies, delays, or deflects does not.
Written claim + evidence8D root causePreserve samples
Emergency Procurement of Genuine Replacement Parts
Initiate an emergency procurement of verified genuine replacement components from an authorised distributor. If the component is EOL and no authorised stock exists, escalate the situation — an EOL part with no authorised inventory is a high-risk sourcing condition that requires careful evaluation of alternative sources or a design change. Do not re-source from the same unverified channel that supplied the counterfeit lot, regardless of price or availability pressure.
Authorised source onlyNo re-sourcing from same channel
Report to Industry Bodies and Review Internal Processes
Report the confirmed counterfeit incident to an industry reporting body — ERAI (Electronic Resellers Association International) for commercial electronics; GIDEP (Government-Industry Data Exchange Program) for US government supply chains; or equivalent regional bodies. Industry reporting alerts other buyers in the market to the same counterfeit lot or supplier, and contributes to the collective intelligence that the entire supply chain depends on to contain counterfeit activity. Internally, conduct a process review: which procurement decision allowed this lot to enter your facility, and what process change prevents recurrence?
ERAI reportGIDEP (US gov)Internal process reviewRecurrence prevention
Summary
Counterfeit electronic components are a supply chain risk that scales with the distance between your procurement and the original component manufacturer. The five types — remarked parts, specification-upmarked parts, fully counterfeit parts, grade-upmarked parts, and rejected scrap — each require different detection approaches, and no single method detects all types. The five detection methods — visual inspection, X-ray, decapsulation, electrical characterisation, and solvent testing — work best as a layered sequence, with the depth of testing calibrated to the source risk and application criticality. The most effective counterfeit prevention is procurement policy: default to authorised distribution channels, require AS6081 certification from independent distributors, demand complete traceability documentation to the original manufacturer, and formalise a risk-proportionate incoming inspection matrix. When a counterfeit is confirmed, the response must be immediate, systematic, documented, and include a report to an industry body — not just an internal corrective action. Short-term cost optimisation through unverified sourcing channels consistently produces long-term costs that dwarf the savings achieved.