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Because copper is no longer a good enough conductor when it it is used in very thin layers, the latest and densest CMOS fabrication processes have begun to repl
by adrian_b 2y ago
Because copper is no longer a good enough conductor when it it is used in very thin layers, the latest and densest CMOS fabrication processes have begun to replace copper with other metals for the first 2 metal layers, which are the thinnest.
It is not known with certainty what metals are currently used by Intel or TSMC, though cobalt and ruthenium have been considered as the most promising choices.
There has been a lot of speculation about whether the choice of cobalt for the thinnest metal layers has been an important cause of Intel's woes with their "10 nm" CMOS fabrication process.
While there were chances for this hypothesis to be true, the actual reasons for Intel's failure to achieve the predicted clock frequencies and fabrication yields with their "10 nm" processes remain unknown, because Intel has never published any information about this.
Whichever was the reason, eventually Intel has succeeded to fix this fabrication process, even if only around 5 years later than in their initial plan, after rebranding it in "Intel 7", at least from the point of view of the achievable performances, which have culminated in Raptor Lake Refresh, though perhaps Intel's incapacity of predicting accurately the reliability behavior as a function of the supply voltage, as demonstrated in many failures of Raptor Lake/Alder Lake CPUs, may indicate that they have never succeeded to understand the exact characteristics of this fabrication process.
- q3k 2y ago> It is not known with certainty what metals are currently used by Intel or TSMC, though cobalt and ruthenium have been considered as the most promising choices. Wait, shouldn't that be easy to find out? Section/delayer a chip and throw it under a SEM-EDX system?
- hnuser123456 2y agoAlright, who here has the delidding tools and SEM? Let's crack this egg
- q3k 2y agoI mean I have access to SEM with EDX [1] and I can (poorly) crack open chips [2], 'just' need to get some LN to run the EDX... I just can't believe this isn't something that another lab has already done and published! [1] - https://wiki.fa-fo.de/equipment:zeiss-dsm-962 https://wiki.fa-fo.de/equipment:zeiss-dsm-962 ; it's still not 100% restored [2] - Here's what I believe to be metal1 on a RP2350: https://object.ceph-eu.hswaw.net/q3k-personal/c98c23b8db73df4f523c5d6f601e8062bc1d3c3dbe68460a93e80d40f1bc2057.png https://object.ceph-eu.hswaw.net/q3k-personal/c98c23b8db73df...
- hnuser123456 2y agoNice! Can you tell that it's copper from the RP2350 image?
- q3k 2y agoThe EDX isn't functional yet, so I can't tell that.
- IlikeKitties 2y agoDer8auer on Youtube is the most likely candidate to figure it out if he so choses.
- adrian_b 2y agoThere are companies that specialize in studying semiconductor chips made with recent manufacturing processes. They write reports with the results of their investigations, which are sold at hefty prices. So the competitors in this domain certainly know exactly what metals are used. This does not mean that these facts are published anywhere in the open literature. In general, trade secrets about what is in a product have rarely any value against well-funded competitors. They may work only to prevent the appearance of new entrants in the market. The secrecy maintained by many companies about how their products really work is very annoying, because it hurts only their customers, never their competitors. The only trade secrets that are enforceable are those about how something is made, not about what it is or what it contains.