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could someone ELi5 the backside power delivery please ?
by tvbv 2y ago
could someone ELi5 the backside power delivery please ?
- bayindirh 2y agoSignal wires and power wires are not routed together, but separately. As a result, transistors are sandwiched between two wiring stacks. Resulting in lower noise, but makes heat removal a bit harder AFAICS. See the image at: https://www.custompc.com/wp-content/sites/custompc/2023/06/Intel-PowerVia-backside-power-delivery-03.jpg https://www.custompc.com/wp-content/sites/custompc/2023/06/I...
- Tempest1981 2y agoHow many power layers are there? Or how do the power "wires" cross over each other? Are they sparse, like wires? Or solid, like the ground plane of a PCB? Are there "burried vias"?
- gostsamo 2y agoAn article on the topic though about Intel: https://spectrum.ieee.org/backside-power-delivery https://spectrum.ieee.org/backside-power-delivery
- AnimalMuppet 2y agoSo, if I understood that correctly, "frontside" actually is the top side, and "backside" is actually the bottom side. They're delivering power from the bottom (substrate) side, and connecting the data on the top side.
- Keyframe 2y agoinstead of signals and power path going through the same side (frontside) causing all sorts of issues and inefficiency, they're decoupling where power is coming from (from the other, backside, err side). More importantly, intel saw it as one of two key technologies of them moving into angstrom era, and was touting itself they'll be the first one to bring it to life (not sure they did).. so this seems to be more of a business power move. more on all of it from anandtech: https://www.anandtech.com/show/18894/intel-details-powervia-tech-backside-power-on-schedule-for-2024 https://www.anandtech.com/show/18894/intel-details-powervia-...
- wwfn 2y agoI'm also clueless. First search brings up https://www.tomshardware.com/news/intel-details-powervia-backside-power-delivery-network https://www.tomshardware.com/news/intel-details-powervia-bac... with a nice diagram It looks like the topology for backside moves the transistors to the middle so "singal wires and power wires are decoupled and optimized separately" instead of "compete[ing] for the same resources at every metal layer"
- __s 2y agohttps://www.imec-int.com/en/articles/how-power-chips-backside https://www.imec-int.com/en/articles/how-power-chips-backsid... has some explanation that's a bit beyond ELI5, but they have 2 pictures: frontside: https://www.imec-int.com/_next/image?url=%2Fsites%2Fdefault%2Ffiles%2F2022-11%2Fimec%2520-%2520Figure%25201%2520-%2520Frontside%2520power%2520delivery.png&w=1280&q=75 https://www.imec-int.com/_next/image?url=%2Fsites%2Fdefault%... backside: https://www.imec-int.com/_next/image?url=%2Fsites%2Fdefault%2Ffiles%2F2022-11%2Fimec%2520-%2520Figure%25202%2520-%2520Backside%2520power%2520delivery%2520-%2520concept.png&w=1280&q=75 https://www.imec-int.com/_next/image?url=%2Fsites%2Fdefault%... Another graphic samsung used: https://www.thelec.net/news/photo/202210/4238_4577_1152.jpg https://www.thelec.net/news/photo/202210/4238_4577_1152.jpg From https://www.tomshardware.com/pc-components/cpus/samsung-to-introduce-backside-power-delivery-to-2nm-class-production-node-report https://www.tomshardware.com/pc-components/cpus/samsung-to-i... > Typically, backside power delivery enables thicker, lower-resistance wires, which can deliver more power to enable higher performance and save power. Samsung's paper noted a 9.2% reduction in wiring length, enhancing performance
- barfard 2y agothe pics go to 404
- __s 2y agothanks, I've fixed them btw, you appear to be shadow banned, probably on account of being downvoted for making short comments like "good" or "I don't get it" Short & simple responses may be adequate at times, but usually people will view it as not adding anything Perhaps reviewing guidelines https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html will give an idea of the ideal being yearned for (granted, it's an ideal). In general, trying to enhance the conversation with relevant information/ideas. "your links are 404" was definitely relevant here
- gcanyon 2y agoHow can you tell someone is shadowbanned?
- vollbrecht 2y agothere is a good youtube video that explains it https://www.youtube.com/watch?v=hyZlQY2xmWQ https://www.youtube.com/watch?v=hyZlQY2xmWQ
- brohee 2y agoNot ELI5 but I found this 20mn video pretty informative https://www.youtube.com/watch?v=hyZlQY2xmWQ https://www.youtube.com/watch?v=hyZlQY2xmWQ
- brennanpeterson 2y agoHalf your wires deliver power, half deliver signal. So if you do both on the same side, you need twice the density of wires. If you split the delivery into two parts, you get double the density without needing to make things smaller.
- blagie 2y agoThis isn't quite right. Big wires (ideally entire planes) deliver power. Small wires deliver signal. Half and half isn't the right split, and you don't want to make power wires smaller. The very different requirements of the two is where a lot of the gains come in.
- mbajkowski 2y agoIt is going to get even a bit more interesting when you consider power gaters and virtual power supplies. Now the real power will be on the back side and the virtual power will be on the front side. Fun time for power analysis.
- brennanpeterson 2y agoTrue! I went a little far in the name of 'eli5'. I think it roughly holds that you gain about a factor of 1.5 in routing density by removing the power distribution, so you can relax some critical patterning. But I havent looked closely in a long time.
- blagie 2y agoOft-missed pedagogical point for working with five-year-olds: Precision is important. You'll notice every comment I made was as simple as I can make it, but /technically correct/. I did not oversimplify to where I changed facts. * It's okay if five-year-olds don't fully understand something. That builds exposure, and leaves a placeholder for future information and curiosity. * On the other hand, if you build out an array of misconceptions, those become very expensive to address later. To a large extent, the younger the child, the more comfortable they will be with being told things they don't understand. A baby doesn't care if you're reading them a book on trucks or a book on homeomorphic transformations; they're picking out the phonemes. A toddler will trust you as an adult, and won't understand 90% of the stuff they hear anyways. A five-year-old, you can still say a lot they won't understand and they'll be not just okay but happy. By maybe seven, lack-of-understanding will become frustrating, and in most cases, by eleven, it's gone. I could write a long essay on this stuff, and why it's so important to maintain that ability to be confused and half-understand, but I very intentionally leave placeholders when working with five-year-olds.
- brikym 2y ago[flagged]
- blagie 2y agoELI5: ICs are manufactured on silicon disks called wafers. Discs have two sides, and traditionally, everything was done on top. We can now do power on the bottom. This makes things go faster and use less power: * Power wires are big (and can be a bit crude). The bigger the better. Signal wires are small and precise. Smaller is generally better. * Big wires, if near signal wires, can interfere with them working optimally (called "capacitance"). * Capacitance can slow down signals on the fine signal wires. * Capacitance also increases power usage when ones become zeros and vice-versa on signal wires. * Big wires also take up a lot of space. * Putting them on the back of the wafer means that things can go faster and use less power, since you don't have big power wires near your fine signal wires. * Putting them in back leaves a lot more space for things in front. * Capacitance between power wires (which don't carry signal) actually helps deliver cleaner power too, which is a free bonus! This is hard to do, since it means somehow routing power through the wafer. That's why we didn't do this before. You need very tiny wires through very tiny holes in locations very precisely aligned on both sides. Aligning things on the scale of nanometers is very, very hard. How did I do?
- consp 2y ago[flagged]
- pmx 2y agoThanks this was a very useful summary for me!
- vintendo64 2y ago