TSMC wafer found in a dumpster – is this the ultimate case of chip binning?

WTF?! A Reddit user claims to have discovered an entire 12nm TSMC wafer discarded in a dumpster near one of the chipmaker’s fabs in China. While it was just a test wafer, the find sparked jokes about cutting it into working GPUs and served as a reminder of the complexities of chip manufacturing.

The Reddit user who shared the pictures, AVX512-VNNI, claims to have found the wafer near TSMC’s Fab 16 factory in Nanjing, China. While not cutting-edge, that fab still produces reasonably advanced 12nm node chips, meaning we’re talking about highly valuable silicon here.

But surely a company like TSMC wouldn’t just dump their IP this way for the world to copy? Indeed, they didn’t, and there’s a reasonable explanation for the “blunder.” The same Redditor pointed out later under the post that this appears to be what’s known as a “test wafer” used to calibrate the lithography machines that pattern the circuitry onto production wafers.

Phew. That’s certainly not as disastrous as tossing out wafers containing actual customer chip designs, like Nvidia’s RTX 50 series GPUs. Those would be far too valuable to misplace. Or perhaps the explanation is even simpler: the Redditor is an employee at one of the foundries and is just joking.

Don’t miss our explainer: What is Chip Binning?

Anyway, for some quick context, semiconductor wafers are the blank slates that get transformed into finished chips through repeated lithographic patterning, deposition, and etching steps. After processing, they get chopped up into individual chip dies, a process known as dicing. These individual dies are then packaged into CPUs, GPUs, and other semiconductor products.

However, not all chips perform equally, even if they come from the same wafer. This is where chip binning comes in. After dicing, each die is tested and sorted based on factors like speed, power efficiency, and defect count. Only the best-performing chips make it into the highest bins, destined for flagship products, while more flawed dies are assigned to lower bins for mid-range or entry-level parts.

So in that sense, this wafer incident could be seen as a rather extreme case of “binning” – as in straight into the trash can. Now, while it’s already established that the wafer was likely a test unit, this hasn’t stopped Redditors from pondering whether it would be possible to salvage the wafer and extract any individual dies.

One commenter suggested using a pizza cutter to dice up the wafer, while another proposed skipping the slicing altogether and wiring up the entire wafer. Interestingly, that’s actually a legitimate technique called wafer-scale computing, so they may be onto something.

The incident also sparked some good-natured roasting of Nvidia over the RTX 50 series, with one commenter quipping “Hey look, someone found the missing ROPs” in reference to some of those GPUs shipping with missing render output units.