Image Sensors World: Anteryon WL Optics Reverse Engineered

Image Sensors World: Anteryon WL Optics Reverse Engineered

Smellphone

You thought cellphones were a public nuisance, now we get smellphones. I may be speaking to a certain older demographic when I mention the old SCTV 3D movie skits where John Candy and co. upped the ante with "smellorama." But that's exactly what this patent for cellphones sounds like.

What brilliant product manager or marketing guru came up with this idea? You think loud cellphone talkers are annoying? You think the old lady with the flowery perfume is bad? Now you can experience the synergies between those two next time you are spending some quality time in an airport departure lounge.

On the other hand, think of the passive-aggressive messages you can now send to your co-workers. This is certain to cause a surge in demand for HR professionals to write new policies to cover smell message services.

The press release on the ConVISUAL site suggests that in the future, you will be able to send the fresh scent of the ocean breeze to your friend stuck in the middle of a kid-western winter. Smells like something entirely different to me. Motorola patented this as reported in InformationWeek. They started with the RAZR followed by the ROKR and the KRZR. Now they have the REEKR.

REEKR brand is the sole property of Andrew Woodard. Thanks Andrew.

Phony Image Sensors

A couple of my colleagues were surprised to say the least this week when the devices they were working on turned out to be rather elaborate fakes. Or not - I'm not sure.

SI was undertaking a reverse engineering project looking at a certain leading CMOS image sensor supplier's sensor who is known to use a certain leading Asian fab to manufacture its devices. Ten units of the chip came from a parts distributor in Hong Kong.

At first glance, the devices appeared as expected. The package was standard-issue for image sensors with hermetically-sealed glass over the sensor die. Everything still appeared normal after removing the sensor die from the package. A typical SoC type of image sensor layout was clear with the pixel array occupying about 26% of this 38 square millimeter chip.

But that's where expectations diverged from reality.

After dropping one die into acid to remove all interconnect layers to get a quick look at the active area patterning, the silicon appeared blank. Then the engineer quickly beveled the IC in order to reveal all of the active layers. Again, there was only whitespace deeper into the chip. Starting with yet another sample from the lot, our lab cross-sectioned through the device. This final step showed us that only the top metal level, color filter array, and microlenses were present.

A senior process engineer not assigned to the project suggested these devices could be mechanical samples. That seemed reasonable. If you wanted to test a new package type for instance, it might make sense to order a few duds but with the BEOL processes down to the microlenses intact. Even more believable would be a BEOL-only device for environmental testing since the filter and microlens arrays are notoriously sensitive to high temperatures. Increasing adoption of imagers into the automotive industry along with research reports of temperature-hardened microlenses adds some credibility to this idea.

However, we bought these devices not as mechanical samples but as working real image sensors under the manufacturers part number. The distributor is from China, so I know what many of you are thinking - another counterfeit chip scandal. There's been a lot made of counterfeiting activity in China. And it wasn't just one or two devices. The whole lot of 10 appears to suffer the same lack of active circuitry.

My best guess at this is that there was a legitimate order placed somewhere for mechanical samples. But more test samples were produced than required for the environmental testing. Some enterprising worker at the manufacturer decided not to waste the extras and found a discount IC distributor on the lookout for cheap devices. At least I hope they were sold at a discount.

The first step to uncovering a possible scandal would be to identify the foundry of origin. I work with some engineers who have a lot of experience in this field. If they are able to determine that these devices were produced one of the expected manufacturers main production lines, then the mechanical sample overrun theory would be supported. If not, then maybe this will be the beginning of a bigger story of a real counterfeiting operation based on chips that could only pass a visual inspection.

This isn't the first strange case of a partially processed, yet fully packaged chip getting into the distribution channel. It's too bad my memory is so bad that I can't remember more details of that chip from several years ago, and the device in question is now buried somewhere deep in the SI chip graveyard. What I do remember is strikingly similar though. Despite containing all the interconnect levels, the polysilicon was an unpatterned, featureless sheet, and there were no vias between metal lines. I guess we weren't as focussed on counterfeit in those days because it never occurred to me at the time, but it may have been another case of it.

My conspiracy theory is that the bean counters took over the fab. Maybe this is the "New Economics of Semiconductor Manufacturing" as described in IEEE Spectrum. Why not save a couple bucks by just avoiding those costly front-end manufacturing steps? After all, with image sensor ASP's getting continuously hammered, what else can they do to keep making a buck?