Dendritic Identifiers as Digital Triggers in Microelectronics Manufacturing

M.N. Kozicki, J. Joseph
Arizona State University and Densec ID, LLC,
United States

Keywords: digital trigger, track and trace, authentication, IC packaging, dendrites


Counterfeit integrated circuits (ICs) have existed in the electronics marketplace for decades but the problem has recently become worse with the tightening of supply and the rise of sophisticated illegal manufacturing capability. Fake products include re-marked used or lower-spec components, substandard cloned devices, and ICs that have been redesigned to include malicious hardware. Manufacturers often attempt to mitigate the problem via the use of hardware blocks and authentication software, which require the inconvenience and cost of having the IC installed in a system and powered up. Concern is building for the most advanced client/server and graphics chips, which comprise advanced logic and memory ICs and less sophisticated chiplets connected within a single package in heterogeneous integration (HI) schemes. To reduce cost, the chiplets are made at relaxed process nodes and thereby can be more readily counterfeited, an issue that will become more possible as the chiplet marketplace moves to a more open structure. The problem of counterfeit microelectronic parts could be significantly reduced via the adoption of digital identity technologies to ensure the authenticity and traceability of components throughout the supply chain. Digital identity requires a connection between the item in the real world and its presence in the Cloud via a digital trigger. Currently available triggers, e.g., QR codes, RFID tags, are not appropriate for the individualized and secure tracking of ICs, and so we have developed the Dendritic Identifier (DI) for this purpose. DI triggers are naturally item-unique, secure enough to resist replication and tampering, and sufficiently inexpensive and scalable to allow them to be deployed on any part, regardless of price or size. DIs comprise branching structures that emerge naturally from Laplacian instabilities in a wide range of material systems. The topology is ideal for identifiers, as dendrites simultaneously possess high information entropy, which ensures a unique “fingerprint” for every part with a very low chance of collisions, and a low structural entropy, which means that faults and noise are seen as departures from the rule-based structure and can be dealt with without the need for complex error correction schemes. Dendrites possess distinctive, localizable, and robust keypoints, allowing them to be reliably read using computer vision approaches. We utilize a formation method that has shown great promise for high speed, high volume, low-cost formation based on the compression of a sub-microliter volume of an off-the-shelf fluid mixture directly on the item to be protected. The materials used depend on the part and the production/use environment and include polymers and metallic inks that can withstand solder reflow temperatures. The dendritic pattern forms spontaneously when the stamping surface is withdrawn, leaving the high-resolution unique identifier on the component without the need for lithography or deliberate individualization. Copy resistance comes from the unclonable optical signal derived from the fluid mixture’s illumination angle-dependent light scattering signature. The triggers are instantly read and authenticated using simple camera systems in the packaging/assembly line or in the field.