The Underground Parts Store: Keeping Fake Chips Out Of The Supply Chain
Supply chain management is a hard problem for engineers to solve. There are fake chips everywhere, and those chips may inexplicably make it into production. This means op-amps that don’t have the right capabilities, capacitors that are the wrong value, and chips that simply don’t work.
Derf Electronics in Poughkeepsie, NY is an electronic parts distributor specializing in managing excess inventory from contract manufacturers. These are the left-over reels of parts from board assembly houses, and every part must be verified to make sure it’s a real, genuine component.
Derf must then verify every single batch of parts, and to do that they’ve come up with some interesting techniques that include visual inspection, x-ray inspection, and even decapsulating the part to look at the silicon die inside.
The problem of fake chips is everywhere in the electronics industry, but no where is it more apparent than the vintage synthesizer market. The chips inside your favorite video game consoles are in very high demand these days, and they’re not making them any more. This opens the door to an entire industry made of fakes that was investigated by David Viens, CEO of Plogue and manufacturer of vintage synth ephemera. To the trained eye, though, it’s almost easy to tell the real chips from the fake ones.
The easiest way to tell the difference between a fake chip and a real one is the appearance of the ejector pin markings. These circular depressions on a chip should have a smooth, near-mirror finish to them. The rest of the chip, on the other hand, has a slightly rough texture. During chip relabeling, the entire surface of the chip is sanded off and new markings are applied. But these new markings are only put on after a coat of ‘black top’ that is meant to replicate the finish of an original chip. If any of this black top gets into the ejector pin markings, you know it’s a fake.
But there’s more to fake chips than rough plastic. If you have a bit of fuming nitric acid, you can decapsulate the chip, revealing the silicon die. At Derf, they looked at an NXP part with a Philips die. This isn’t unusual; NXP bought Philips a few years ago, and the dies and masks have remained unchanged.
But visual inspection will only get you so far. By carefully inspecting the machine marks on a pin, you’ll see clean cuts and smooth tooling marks on a real chip. The fake chip will have the same texture all over the pins, indicating those pins have been replated.
There’s a wealth of information that can be gleaned from a visual inspection of a chip. Simply by looking at the surface texture of a chip, or the tooling marks on a pin can reveal if a chip is fake or not. That’s important when it comes to supply chain management, and with a trained eye, a simple microscope can save millions of dollars in time and effort.
