RFID Prox Card Failure Analysis - Version 2.0

Images made through a microscope. All subject types.

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Bob-O-Rama
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RFID Prox Card Failure Analysis - Version 2.0

Post by Bob-O-Rama »

A colleague of mine came to me with a problem "because you are into all sorts of weird sh*t )

We had a bumper crop of HID Prox ( 125Khz ) ID cards which failed this year, many had a very visible "melt" spot around where the RFID chip should be. Excuse the first few from the mobile phone 8-[ of extracting the dies.

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I then used a mini core saw to cut out the RFID chip area from several of the cards based on the location of the dimple, then dissolved away the PVC card material in solvent:

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After some cleaning, this produced a "rich deposit" of RFID chips and fragments.

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To give you a sense of size, the die is about 1 x 1.5 mm. The leads looks ridiculous.

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And now to the microscope... This is a hasty stitch ( not great ) of 3 shots.

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About half of the chips are broken at the same spot, near the pads. When the chip is broken under the pad, it is held together, like this one:

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You can see the crack extends across the whole die as seen in this crop.

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The chip itself is a standard issue Atmel part used for ... RFID.

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The best working theory is that people are exposing the cards to wireless charging stations. The field coil goes to a rectifier that produces power for the chip. When there is an excess of power, it shunts it through a diode, so I suspect the analog section under the pads over heats and the chip cracks.
Last edited by Bob-O-Rama on Tue Dec 06, 2022 12:40 pm, edited 3 times in total.

rjlittlefield
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Re: RFID Prox Card Failure Analysis

Post by rjlittlefield »

Interesting stuff!

But, I'm seeing a lot of broken image icons, to go along with the two chip images that show up well. For example there's an img tag that references https://photos.smugmug.com/photos/i-Vrk ... MQC-X3.jpg . It shows as a broken icon, and when I try to visit that URL in a separate browser page, I get an http error 404, page not found. I suppose this could also be smugmug's way of reporting a permission problem.

The only two images that are displaying properly link to https://photos.smugmug.com/Infinity-Pho ... adj-X3.jpg and https://photos.smugmug.com/Infinity-Pho ... Adj-X3.jpg .

--Rik

Scarodactyl
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Re: RFID Prox Card Failure Analysis

Post by Scarodactyl »

This looks like fun but most of the images are broken for me.

Macro_Cosmos
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Re: RFID Prox Card Failure Analysis

Post by Macro_Cosmos »

The two that shows up demonstrates lots of nice detail, I like it.

Bob-O-Rama
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Re: RFID Prox Card Failure Analysis

Post by Bob-O-Rama »

"I truly hate everything!" sorry for that. I think its fixed. I normally check these things in private browser to make sure, but I got lazy. -- Bob

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