How to Identify Remarked or Re-Labeled ICs

In complex electronics supply chains, IC remarking (re-labeling or re-marking) is one of the most common identification-related risks. Remarking refers to secondary processing of package markings—such as part number, date code, lot code, or brand identifiers—so that the device appears inconsistent with its true origin. This practice does not necessarily change the internal structure of the IC, but it undermines traceability and may coexist with refurbishment, grade-downgrade substitution, or the recirculation of scrapped materials. As a result, remarking can introduce uncertainty into system reliability and compliance. Therefore, any conclusion about remarking must be based on cross-verification of multiple evidence sources rather than a single surface observation.

1. Risk Context and Typical Remarking Processes

From a laboratory risk-assessment perspective, remarking is generally driven by three motivations:

a) Value arbitrage: disguising lower-cost or lower-grade devices as higher-value parts;

b) Time or lifecycle masking: changing old or obsolete lots into newer date codes to meet delivery or qualification expectations;

c) Source concealment: altering brand, origin, or lot information to obscure the real supply route.

In terms of processing methods, common techniques include overcoating the original markings and reprinting new ones, locally modifying existing marks (often on date or lot codes), or fully re-marking by laser or ink. Because these operations typically involve sanding, repainting, cleaning, or secondary engraving, they often leave detectable deviations in surface appearance, material properties, or internal structure.

2. Marking and Surface Consistency Screening (Visual + Microscopy)

Visual inspection is the first screening layer. Its objective is not to “find cosmetic defects,” but to identify risk signals that deviate from original manufacturer processes and to classify lots accordingly. Laboratories should establish OEM baselines and focus on:

Font and layout consistency: OEM markings show strong uniformity in stroke width, character spacing, alignment, line spacing, and edge margins. Remarked parts often present uneven spacing, tilted characters, or layouts inconsistent with datasheet examples.

Marking logic and code validity: Part numbers, date codes, and lot codes should follow the manufacturer’s coding scheme (digit length, week/year format, plant code structure, etc.). Mismatched rules or implausible code ranges warrant escalation.

Surface condition and texture: Non-uniform gloss, localized reflectivity differences, directional micro-scratches, coating boundaries, or cleaning residues may indicate sanding, repainting, or reprinting.

In-lot uniformity: Devices within the same reel or tray should display a consistent manufacturing style and close lot proximity. Clear “dual-process peaks” or mixed-style populations within a lot are significant risk indicators.

If visual screening suggests medium-to-high risk, microscopy and oblique lighting should be used to reinforce evidence:

Laser-etch edge quality: OEM laser marks usually have sharp edges and uniform depth. Secondary laser marking may show rough edges, inconsistent depth, or localized overheating.

Ink adhesion characteristics: OEM ink markings typically exhibit stable thickness and clean boundaries. Secondary ink may present pooling, bleed-out, bubbles, or uneven penetration into micro-textures.

Sanding or overcoat traces: Resurfaced packages often retain fine, directional abrasion marks and show unnatural “wave-like” reflections or local flatness irregularities under oblique light.

Results at this stage can support a preliminary assessment, but confirmation should rely on objective measurements and structural consistency checks.

3. Objective Measurement and Structural Consistency Verification

When remarking is suspected to involve overcoating or surface treatment replacement, material characterization can provide objective support:

XRF (X-ray fluorescence) enables rapid screening of surface elemental composition and plating characteristics. Significant deviation from known-good baselines or same-lot authentic references may indicate secondary coating or non-OEM surface processing.

FTIR or coating analysis can further confirm polymer composition and film characteristics, supporting detection of paint or overcoat differences.

It is important to note that material differences do not automatically confirm remarking, but they substantially strengthen the objectivity of the overall conclusion.

If the risk motivation includes value arbitrage or grade-downgrade substitution, X-ray/CT should be applied to verify whether internal structure matches the claimed device. Typical checks include die size and position, leadframe and wire-bond layout, and any abnormal voiding or re-work signatures. This step answers whether the internal construction is consistent with a correct device, but it does not directly prove that surface markings were altered, so it must be interpreted together with surface evidence.

For critical applications or lots with conflicting evidence, decapsulation and die identification may be used as the final adjudication method. By comparing die markings, layout features, mask revisions, and fab identifiers against the stated part number, laboratories can confirm authenticity. As decapsulation is destructive, it should be performed only when sample sufficiency, risk-benefit justification, and customer authorization are clearly established.

4. Tiered Workflow and Traceable Decision System

To reduce subjective bias and ensure consistent conclusions across lots and inspectors, remarking identification should be formalized into a tiered verification workflow with full traceability. A recommended structure is:

Level 1: Rapid Screening

Visual inspection and in-lot consistency checks for initial risk grading, focusing on non-OEM marking or surface indicators.

Level 2: Evidence Reinforcement

Microscopy/oblique-light inspection combined with manufacturer coding-rule validation to form a defensible preliminary conclusion.

Level 3: Objective Cross-Verification

Material and structural measurements (e.g., XRF/FTIR and X-ray/CT) used to cross-validate anomalies observed in Levels 1–2.

Level 4: Final Confirmation (as needed)

Decapsulation and die identification applied when risk is high, application criticality is strong, or evidence conflicts remain.

At each level, laboratories should systematically archive images, raw measurement data, and documented decision rationales in a standardized format. This ensures conclusions are reviewable, auditable, and suitable for downstream supply-chain tracing and post-event analysis.

5. Conclusion

Identifying remarked ICs is a systematic task grounded in consistency analysis and multi-source evidence cross-verification. Laboratories must remain sensitive to process anomalies while strictly respecting evidentiary boundaries: any definitive judgment should rely on multiple corroborating methods and complete documentation. Only through a structured screening path can stable, repeatable counterfeit-mitigation capability be achieved in real supply-chain environments.

In incoming quality management and high-risk lot verification, when more systematic multi-method testing is required, laboratories with integrated capability—such as Rapid Rabbit Laboratory—can serve as an optional third-party support resource, providing a more reliable basis for engineering evaluation.