5 ms·
Should be easy to compare - sand down both the cheapo and a legit one (with a similar datecode) with fine sandpaper, clean with isoprop and shove under an optic
by q3k 1y ago
Should be easy to compare - sand down both the cheapo and a legit one (with a similar datecode) with fine sandpaper, clean with isoprop and shove under an optical microscope - you can then tell how similar/dissimilar the dies are, you don't even have to look for markings or anything super legible, or even sand them to the same metal layer.
Clones tend to be vastly different - different technology node, architecture, die size, etc. - that's because they are generally functional clones, not mask clones.
(also, as a general shoutout to the low tech sandpaper technique for exploratory work, here's a sanded down RP2350 thrown under a clapped out SEM: https://object.ceph-eu.hswaw.net/q3k-personal/484e7b33dbdbd914f6bb8974741b143cf727262205ecedf8152ce8d1935c35ba.PNG https://object.ceph-eu.hswaw.net/q3k-personal/484e7b33dbdbd9... https://object.ceph-eu.hswaw.net/q3k-personal/3290eef9b6b9adf78f909a673f84a9fea69741360e7012d77147c054ab8c8d7b.PNG https://object.ceph-eu.hswaw.net/q3k-personal/3290eef9b6b9ad... )
- cheschire 1y agoIt may not even be a clone. As the author said, it could just as easily be production line items that were tested and found to be outside of spec tolerances and resold off-label.
- q3k 1y agoWell, that's the point of the experiment, to figure out if it's a clone or a reject :).
- throwup238 1y agoTI makes all their analog stuff in house so that's unlikely. That's far more common for fabless companies that send their parts off to an outside fab.
- cheschire 1y agoWhat does TI do with their out-of-tolerance products? Straight in the garbage?
- throwup238 1y agoYes, though depending on the product line it may be binned into lower quality parts first. Remember though, the marginal cost of these chips is so small the packaging is usually more expensive than the silicon. They often get tested before the wafer is even sliced up so any waste is hardly worth mentioning until you get into modern processes with large error rates and huge chips like CPUs.
- 15155 1y agoTI isn't patterning $10000 wafers at 3nm with massive chiplets and questionable yield, they are making mostly commodity ICs on cheaper processes - they can afford to discard rejects.
- Lerc 1y agoI think the implied question is do they discard, or do they destroy. Discarded things tend to get lost. Lost things tend not stay in the Anduin forever.
- LeifCarrotson 1y ago> "Discarded things tend to get lost. Lost things tend not to stay in the Anduin forever." I'll have to put that on a warning label near our non-conforming-product containment shelf!
- pinkmuffinere 1y agoLol I love the deep cut to LOTR! Took me a sec but then brought me so much joy. Viva la nerds!
- mikewarot 1y agoNot only that, leakage goes way up as you shrink the transistors, an ADC on a 3nm wafer would require a complete redesign, if it could be made to work at all.
- Arubis 1y agoBinned wafers are viable source material for photovoltaics.
- Hasz 1y agoI have done this a bunch of different times, mostly to resolve sourcing disputes. Dissolving in boiling sulphuric acid/nitric acid will make quick work of most epoxy packaging IMO, I have mostly seen mislabeling, rebinning, and passing off obvious QC rejects. example from many years ago: https://www.youtube.com/watch?v=e6DfBuPwAAA https://www.youtube.com/watch?v=e6DfBuPwAAA
- q3k 1y ago> Dissolving in boiling sulphuric acid/nitric acid will make quick work of most epoxy packaging That's the better method of course (results wise), but it's not nearly as accessible, hence my recent evangelism of the virtues of 2000 grit sandpaper.
- jacquesm 1y agoI like it. I've used sandpaper to solve some interesting problems in the past as well with great success. I suspect we are only seeing the beginnings here in a trend of high-tech applications of fine grit paper.
- Terr_ 1y agoI expect it's much easier to acquire fine sandpaper, yet my inner child yearns for laser decapping. (Or I suppose more than "decapping", depending on the depth.)
- jacquesm 1y agoHigh power lasers are becoming more and more affordable. Laser ablation is definitely an option but you really want to have some proper fume extraction around that.
- BertoldVdb 1y agoLaser decapping will destroy the die, except if you have a rare package that does not mix glass in the epoxy. You could still compare the internal structure of the package and bonding, but the die itself is mostly destroyed.
- fullstop 1y agoI don't know if we can ping people here, but this looks like something that would be right up Ken Shirriff's alley. 1. https://righto.com https://righto.com