The Digital Autopsy: X-ray Tomography to Unmask Counterfeit Chips
In sectors where reliability is vital, such as aviation or medicine, the inexplicable failure of a component can trigger a crisis. To solve these mysteries, a high-tech forensic investigation is deployed whose main objective is to identify electronic counterfeits. The star technique in this process is X-ray tomography, a non-destructive method that acts as a digital autopsy scanner, revealing the deepest secrets of an integrated circuit without touching it. 🔍
Three-Dimensional Scanning: From Suspicion to Volumetric Model
The process begins with specialized equipment, such as a high-resolution X-ray microscope. This device does not capture a simple flat image, but hundreds of two-dimensional projections while the component rotates 360 degrees. From this vast dataset, reconstruction software generates a 3D volumetric model with micrometric precision. This digital model, which can be a dense point cloud or a polygonal mesh, reveals the complete anatomy of the chip: from the silicon substrate layers and intricate metal traces, to the delicate bonding wires and possible manufacturing defects in the encapsulation. 🧩
Key elements revealed by tomography:- Layer architecture: Visualization of all metal and dielectric layers that make up the circuit.
- Interconnections and vias: Precise mapping of electrical connections between different levels of the chip.
- Material anomalies: Detection of voids, delaminations, or incorrect material inclusions in the epoxy encapsulation.
X-ray tomography turns the chip into an open book, where each page is a layer and each connection a word that can be read without destroying the volume.
Forensic Analysis: Comparison with the Original Truth
Once the 3D model of the suspicious device is obtained, the comparative forensic analysis phase begins. Using scientific visualization software, experts segment and isolate specific structures for examination. The acid test consists of contrasting this scan with the reference of a genuine component or, optimally, with the original design files (GDSII). Tools like KLayout allow pixel-by-pixel overlay between the theoretical design and the captured physical reality. 🕵️♂️
Discrepancies that betray a counterfeit:- Missing or ghost connections: Traces or vias that appear in the design but not in the physical chip, or vice versa.
- Undesired bridges or short circuits: Metal connections where there shouldn't be any, resulting from a deficient manufacturing process.
- Altered geometry: Transistors with different sizes or a logic gate arrangement that does not match the authentic architecture.
Irrefutable Digital Evidence
The identification of these discrepancies constitutes the irrefutable forensic evidence of a counterfeit. This digital autopsy process not only confirms the fraud but also helps trace its origin and understand its security implications. The next time a critical system fails, behind the investigation there might be an engineer analyzing a 3D model and discovering, with frustration and precision, that where there should have been a buffer there is a NAND gate placed by a counterfeiter. This technology is the silent guardian of integrity in modern electronics. ⚖️