Manufacturing Bits: Oct. 11

IC security using AFMs
The National Institute of Standards and Technology (NIST) has developed a probe assisted doping technique (PAD), a technology that could help prevent counterfeit chips and electronic devices from entering the market.

PAD involves creating a unique ID tag on every chip using an atomic force microscope (AFM). Basically, an AFM system incorporates a cantilever with a tiny hard tip or needle. Using AFMs, ID tags are embedded into a device during the manufacturing process. The device is easily authenticated using RF, which in turn ensures a secure supply chain for components in critical systems, according to NIST.

PAD is one of many ways to prevent nefarious groups from developing counterfeit chips, which ultimately end up in systems of all types. It’s a big problem as the counterfeit chip market had a worldwide value estimated at $75 billion in 2019, according to Rambus.

Today, there are already well-entrenched security solutions in the IC market. For some time, the IC industry has used traditional non-volatile memory for secure code storage applications. This memory can store a few bits of authentication information for security purposes using electric-fuse (eFuse) or anti-fuse technology. This is one way to prevent counterfeit chips.

The current solutions may not always be full-proof, prompting the need for a new technology. For example, Multibeam is developing a security lithography technology. Basically, using multi-beam technology, Multibeam’s system can pattern and embed a unique ID inside each IC during fabrication. The system hard codes the ID at the silicon level, making it tamper-proof. The information can link to a secure database to store individual chip data.

NIST has another solution–PAD. In the PAD process, a vendor deposits a thin layer of aluminum atoms on a wafer. The wafer itself consists of chips based on a given design. All told, PAD produces customizable superlattices of p-n junctions on a semiconductor substrate, according to NIST. The diameter of the implanted region is no larger than 200nm.

Then, a vendor would make use of an AFM. The tip of an AFM pushes some but not all of the atoms down in the surface. Then, the wafer is heated, which alters the atoms.

Each dopant-modified lattice has a unique impedance. “As a result, the lattice can serve as a distinctive electronic label — a nanometer-scale version of a QR code for the wafer,” according to NIST.

To authenticate the chip, the device is probed using radio waves. “When a scanner directs a beam of radio waves at the device, the electrically altered lattices respond by emitting a unique radio frequency corresponding to their impedance. Counterfeit devices could be easily identified because they would not respond to the scanner in the same way,” according to NIST.

“The doped structures bestow a customizable radio frequency (RF) electronic signature, which could be leveraged into a distinctive identification tag. This will allow any manufactured item (integrated circuit, pharmaceutical, etc.) to be uniquely authenticatable. Applications of this technology include enabling secure Internet of Things (IoT) and eliminating counterfeit products,” said Jungjoon Ahn, a NIST researcher in a paper.

“We’re putting a sticker on every device, except that the sticker is electronic and no two are identical because in each case the amount and pattern of the dopant atoms is different,” said NIST researcher Yaw Obeng.

“This research is key because it offers a means to uniquely identify components by a secure, unalterable and inexpensive means,” added Jon Boyens, a researcher with NIST’s Computer Security Division.

Anti-counterfeiting inks
ITMO University, Bauman Moscow State Technical University, and the University of Toronto have developed a special ink for anti-counterfeiting protection.

Researchers believe that their anti-counterfeiting technology is superior than existing solutions.

Researchers devised nanocolloidal materials, which can be used as unique ID tags. The materials, which can be applied to the surface of various products, involve an ionic gelation of nanoparticles with different charges. The materials are based on poly(ethyl methacrylate) polymer particles.

The nanoparticles have different optical activity levels. They glow when exposed to light at different wavelengths. “We can create multilayered hidden patterns that can only be seen at different wavelengths. This way, even if the perpetrators succeed in forging a part of the tag, there’s a good chance that they wouldn’t be able to forge the other. What’s more, the difference between the original pattern and the forged one will be immediately apparent,” according to researchers. “In addition, thanks to every image being an optically active structure, we can expand the range of methods used for their analysis and verification. For example, it can be a bar code or a QR code that can only be seen in UV light, and its inverted version – only in light at a different wavelength.”

“Manufacturers lose over 20% of their income to counterfeiting. But in truth, this is an issue for customers, as well – if it’s food or cosmetics that we are talking about, counterfeit goods can be harmful for one’s health. This is why any method that help deal with counterfeiting are in demand. As of now, there’s a competition between radio-frequency methods and the more classical hidden image methods. RFID tags make use of rare-earth metals, which are also used in electronics and so on; they are currently used to mark upscale goods and aren’t very good for mass production. Plus, they are harmful for the environment, and today, there’s a focus on green technology and renewable sources,” said Egor Ryabchenko, a researcher at ITMO.