Counterfeit Detection Using X-Ray Image as a Fingerprint

This Thursday, October 18 at 3PM, our VP of Technology Dr. Glen Thomas will present the paper “Counterfeit Detection Using X-Ray Image as a Fingerprint” at the SMTA International Conference in Chicago, IL. Here’re the abstract and slides – don’t miss the live show to ask questions and learn more from the expert in x-ray inspection!

Abstract:

Taggants have been widely adopted in the fight against counterfeit components. The process of applying taggants to components consists of first determining the authenticity of the part. This step can be achieved by either knowing that the component is authentic (by a well-documented chain of custody from the original component manufacturer), or by running a batch of tests to sufficiently determine the conformity of the component to its original specifications.

Taggants are often chemical compounds with a unique mix of elements that are embedded into the surface of the component. This unique mix effectively introduces a fingerprint to the component, and the combination of component identification and fingerprint is carefully uploaded to a database. Later in the supply chain, the taggant can be read back by special sensors to verify that the component and the attached fingerprint match as in the database. Some of the shortcomings of this method include the need to prepare this unique compound, the need to correctly apply it to the surface of the component, and the need to use expensive sensors to read back the fingerprint of the component at the point of use. There is also the risk that the taggant might end up in the wrong hands, which would allow such individuals to criminally authenticate counterfeit components.

The other major shortcoming of taggants relate to the authenticity protection of printed circuit board assemblies (PCBA). PCBAs can be considered electronic systems, each with hundreds or thousands of electronic components. Thus, the application of a unique taggant to each component is not feasible.

In this work, we introduce the use of the x-ray image as the unique fingerprint for an electronic component or PCBA. Unique features of the x-ray image such as solder voids, cracks, part alignment, die attach porosity and voiding, die placement and alignment, and wire bonding diagram. These are just a few of the many features in the x-ray image that can be used in tandem to create a unique fingerprint for a single component or an entire PCBA. This technique can also be expanded to mechanical objects by utilizing other idiosyncratic features of the part – such as voids and porosity – to generate the x-ray image fingerprint.

The x-ray image fingerprint is calculated using unique algorithms and inserted into a custom database. Unlike taggants, the x-ray image technique does not allow for any adulteration because we are not adding any material to the component. Instead, the x-ray image fingerprint technique uses features of the material itself to generate the fingerprint.

Later in the supply chain, to read back these features to verify the authenticity of the component or PCBA, the user needs to image the part back with a compatible x-ray machine. The identification of the part will determine which locations and features are to be used to retrieve the fingerprint from the database. The same algorithms are then used to determine if any changes have occurred to the part, and if the part is the same as introduced in the database.

It is important to note that much like taggants, normal usage of the component or PCBAs, even under thermal cycling, humidity and altitude variations, will not change the features utilized to create the x-ray image fingerprint of the parts. However, reworking these parts will cause a fingerprint mismatch. This is an added advantage of the x-ray image technique over taggants, because unlike taggants x-ray image fingerprint can identify illicit reworked parts.