NTAG213 chip from NFC RFID label

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rjlittlefield
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NTAG213 chip from NFC RFID label

Post by rjlittlefield »

First, to translate the title...
  • NTAG216 = a manufacturer's model number, sort of
  • chip = integrated circuit
  • from = I ripped the thing apart to see what was inside
  • NFC = Near Field Communications
  • RFID = Radio Frequency IDentification
  • label = thin flat sticky thing
Now, the face of the chip. This is 0.72 x 0.48 mm.

Image

Various views and pieces. The glass slide is 2" wide. The metal washer with the shiny thing sitting on it is part of the setup that I used to burn away the plastic and epoxy. The shiny thing on the washer is mostly a small portion of the antenna coil, with the chip still sitting under the two pieces of antenna that are now only tenuously attached to it. The fully cleaned chip that is shown in the first image is glued to the slide between the washer and the label. You'll have to look close, because in this image the chip itself is only about 5 pixels square.

Image


Zooming in closer, plus some montaging, this is the decapsulated chip sitting next to its sibling which is still fully functional inside the label. You can see that the antenna coil is split and is bonded to the chip in all four corners. It turns out that two of those bonds are only mechanical at this point. When manufactured, the chip has four electrical connections, two for the antenna and two more for GND and TP. But the manufacturer's documentation at https://www.nxp.com/docs/en/data-sheet/ ... 15_216.pdf makes clear that "Pads GND and TP are disconnected when wafer is sawn."

Image


This chip is particularly interesting to me because portions of it have richly detailed 3D structure. Here are a couple of stereo pairs at high magnification, cropped in so that the structure is easier to see. These are Zerene Stacker synthetic stereo at +-8 degrees, so 16 degrees total stereo separation. I want to say that this exaggerates the 3D structure, compared to what you'd see through a stereo scope, but these structures are so small that with my stereo scope they're basically invisible even at 45X. These were shot at 20X NA 0.42, same as the image at top of post, but here we are strongly zoomed in by cropping.

Image

Image

In offline communications I've been asked how I photograph these things. Photographing flat at this magnification often makes a mess because the only light that gets into the objective is what bounces off the edges of 3D structures. The structure looks a lot better if the flat surfaces are illuminated also. That could be done with through-the-lens illumination ("episcopic brightfield"), but the trick I use is to just tip the chip a little (about 8 degrees), so that some diffuse illumination can get around the objective, bounce off the mirrored surfaces of the chip, and still get into part of the objective. The light does not get into the whole objective, which causes some strange apparent lateral movements that depend on focus, even though no physical lateral movement happens.. But the stacking process sorts it out pretty well, so we end up with good images in the end.

Here is a stereo pair showing the setup. This pair is shot using cha-cha technique with a cell phone, then run through StereoPhoto Maker for alignment and cropping. I was surprised at how simple and effective this technique turns out to be. Just maneuver my head into position so that my real eyes can see what they want, then position the camera of the cell phone directly in front of each eye while taking the shot. I can get the cell phone aligned with my eyes to within a few mm, so this really is a matter of what-I-saw-is-what-I-got. In this image the chip is sitting in the middle of the circular hole punched in black velvet paper that suppresses reflections from the rest of the glass slide. Careful positioning of my head was required so that both eyes could see the chip, and that positioning was nicely preserved in the images captured by camera.

Image

--Rik

More details: Canon R7 camera, Mitutoyo DCR-150 tube lens, Mitutoyo M Plan Apo 20X NA 0.42, focus-stepped at 1 micron. Decapsulated by 10 minutes burn-off, held between washers sitting on a red-hot electric heating coil, then ultrasonically cleaned after cooling.

Marcepstein
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Re: NTAG213 chip from NFC RFID label

Post by Marcepstein »

Rik, what iso were you shooting at?

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Re: NTAG213 chip from NFC RFID label

Post by rjlittlefield »

Marcepstein wrote:
Thu Mar 23, 2023 2:39 pm
Rik, what iso were you shooting at?
I assume you're looking at the rather high noise levels. These are stacked from in-camera JPEGs, shot at ISO 100, stacked with PMax, then heavily sharpened in post-processing (Photoshop Filter > Sharpen > Unsharp Mask with Amount: 75%, Radius: 4.0 pixels, and Threshold: 0), with no noise reduction. The purpose of this treatment is to bring out detail that would otherwise be severely softened due to diffraction, without risk of introducing misleading artifacts through the use of a computed depth map or "smart" sharpening such as Topaz AI. Yep, they are noisy, but at least the noise is random.

--Rik

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Re: NTAG213 chip from NFC RFID label

Post by Marcepstein »

No, actually just curious because you mentioned the R7 . Im seeing minute subject vibrations at high magnification 3x+ which I think is from a nearby highway and am trying higher iso's to get a greater shutter speed. I haven't processed any of the images yet. Thanks for the explanation tho, informative.

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Re: NTAG213 chip from NFC RFID label

Post by rjlittlefield »

At high magnification, like the 20X used here, I usually shoot with low power flash so as to get short effective exposure times that will freeze out whatever motion there may be. In this case I was shooting around 1/8 power with two flashes, so probably around 1/5000 second effective. Unlike my earlier Canon cameras, the R7 does support flash even with electronic first shutter, as long as the second shutter is mechanical. So that's what I used in this case -- electronic first shutter, mechanical second. To go full electronic shutter I would have to jump through some hoops as described at viewtopic.php?f=8&t=45281 , not worth the trouble in this case.

--Rik

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Re: NTAG213 chip from NFC RFID label

Post by lothman »

rjlittlefield wrote:
Wed Mar 22, 2023 3:41 pm
Here is a stereo pair showing the setup. This pair is shot using cha-cha technique with a cell phone, then run through StereoPhoto Maker for alignment and cropping. I was surprised at how simple and effective this technique turns out to be. Just maneuver my head into position so that my real eyes can see what they want, then position the camera of the cell phone directly in front of each eye while taking the shot. I can get the cell phone aligned with my eyes to within a few mm, so this really is a matter of what-I-saw-is-what-I-got. In this image the chip is sitting in the middle of the circular hole punched in black velvet paper that suppresses reflections from the rest of the glass slide. Careful positioning of my head was required so that both eyes could see the chip, and that positioning was nicely preserved in the images captured by camera.
:shock: =D> :shock: :lol: :mrgreen: =D> =D> =D>

Wow that is STUNNING. But what is cha-cha technique and how do you align the cell phone with your eyes within a few mm. Or could this be done by shifting the cellphone by the pupil distance I know from my reading glasses?

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Re: NTAG213 chip from NFC RFID label

Post by rjlittlefield »

"Cha-cha" stereo is where you take one picture, move the camera, and take another picture. To use it here, I first figured out which camera lens on the phone's back was going to be used at the scale and distance that I wanted to photograph, and mapped that to a corresponding point on the screen side of the phone. Call that P for lens Position. To set up the shot, I moved my head around until both eyes could see what I wanted, in particular the chip location as seen through the gap between diffuser and positioning stack. Carefully holding my head at that position, I closed my left eye, moved the cell phone until P appeared in my right eye just where the chip had been before the phone got there. Click for picture #1. Then, still without moving my head, I closed my right eye, moved the cell phone until P appeared in my left eye where the chip had been, and click for picture #2. Load both pictures into StereoPhoto Maker, Adjust > Auto Alignment, crop, and the job is done.

If I measured the difference in lens positions, indeed that would be very close to the pupil distance for my glasses. But if I had tried to take this pair with the camera mounted on a stand, then to be sure that both images were showing that nearly hidden chip position, I would have had to jockey back and forth between left and right positions until both of them worked. It was much faster and easier to just move my head, monitoring both eyes at the same time, then use the actual eye positions as references for the phone.

The "few mm" refers to my estimate about how well I can line up P with the position of the chip as it appeared just before I moved the phone into place.

--Rik

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Re: NTAG213 chip from NFC RFID label

Post by rjlittlefield »

Here is the edge of the chip, as manufactured, after decapsulation.

This is a 100% crop of the camera resolution stack (Canon R7, nominal 20.8X magnification). The fine layers at top are where the active circuitry is formed. Those are 1.2 microns per light/dark pair. I suppose that must be metal and insulator. The total layered surface thickness is only about 9 microns.

Image


I was surprised by how distinct the active surface layering is, and also by how much fine structure there is within each layer. I was expecting that when the chips were sawn out of the wafer, the cut edges would only go through inactive areas of the wafer so we would see only uniform layers. But I guess the cut zones actually contain some temporarily useful circuitry (for testing, maybe?), or maybe something about the cutting process produces the structure we see here.

I have no idea at all what causes the bold layering in the body of the silicon.

Here's the whole edge: 0.72 mm long by 0.12 mm thick.

Image

--Rik

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Re: NTAG213 chip from NFC RFID label

Post by rjlittlefield »

I really should say something about what these chips do.

Quoting here the explanation offered by ChatGPT:
NTAG213 is a type of Near Field Communication (NFC) chip developed by NXP Semiconductors. These chips are commonly used in a wide range of applications that require contactless data transfer.

Some common uses of NTAG213 chips include:
  1. Access control: NTAG213 chips can be used as a secure method of access control for buildings, rooms, and other secure areas.
  2. Electronic ticketing: NTAG213 chips can be used for electronic ticketing, allowing users to quickly and easily access public transportation, events, and other services.
  3. Loyalty programs: NTAG213 chips can be used to manage customer loyalty programs, allowing businesses to reward their customers for repeat business.
  4. Product authentication: NTAG213 chips can be used to authenticate products, ensuring that they are genuine and not counterfeit.
  5. Smart advertising: NTAG213 chips can be used to deliver targeted advertising to consumers based on their location and other demographic data.
Overall, NTAG213 chips are versatile and widely used in a range of industries and applications that require contactless data transfer.
All of this hinges on the chip's ability to maintain a small amount of nonvolatile data on-chip, and to transmit, receive, or modify that data when properly commanded on the RF communications channel. For the NXP213, this is 137 bytes of read/write memory, plus a unique chip ID.

In addition to working with specially made NFC reader/writers, these tags can also be read and written by most cell phones. For example when a blank label is scanned by the NFC Tools app loaded onto my Android phone, the screen looks like this:

Image

But if I program the label to contain a URL and a bit of text, then the NFC Tools app says this:

Image

Image

If this non-blank label is scanned by my NFC-enabled phone when it is not running the NFC Tools app, I get a popup window that says "Open link? // Your phone received a link through NFC: // https://photomacrography.net/forum " and offers options to Cancel or Open link. Clicking on Open Link immediately puts me into my browser viewing this forum.

Like all NFC communications, this only works over short range, about 20 mm from the center back of my phone.

It's worth noting that "NTAG213" seems to be a bit generic, at least in the marketplace. I have some different labels that were sold on eBay as NTAG213, but are seen by NFC Tools as "NXP - Mifare Ultralight", with Technologies available of "NfcA, Ndef". Internally, they have a completely different chip layout, which carries the number F8213B. The web suggests that those chips are from Shanghai Feiju Microelectronics Co, versus the ones in this thread that seem to be from NXP.

One more bizarre note: the labels containing the F8213B chips came from China as expected, while the labels containing the NXP chips shown in this thread were advertised by eBay as being from China, but when the package arrived the customs declaration said that it came from Kyrgyzstan. I cannot make sense of the world these days.

Anyway, regarding NFC labels in general, I have no idea what I personally might do with these things, but it's nice to have a better understanding of what they do and how they work.

--Rik

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