4 ms·
> Silicon is already at the point where there are only a dozen or so dopant atoms per gate, so a fluctuation of one or two atoms can be enough to impact behavio
by dataflow 5y ago
> Silicon is already at the point where there are only a dozen or so dopant atoms per gate, so a fluctuation of one or two atoms can be enough to impact behavior.
How in the world do they get such a precise number of atoms to land on billions of transistors? It seems so hard for even one transistor.
- quantified 5y agoYes, materials science, lithography and chip fabrication are the real wizardry of the information age. A 20nm chip is badass on its own yet old school now.
- rrss 5y agoFWIW, the active channel volume is much more than a dozen atoms in a modern FinFET process. For a ~5nm process, there might be only a few dozen atoms across the width of the fin, but the other dimensions are much larger, for a total of probably somewhere around hundreds of thousands of atoms per channel. see e.g. https://fuse.wikichip.org/news/2408/tsmc-7nm-hd-and-hp-cells-2nd-gen-7nm-and-the-snapdragon-855-dtco/ https://fuse.wikichip.org/news/2408/tsmc-7nm-hd-and-hp-cells... and other wikichip articles for some dimension info. but regardless, modern semiconductor manufacturing processes are incredible. the much-too-brief summary is that they shine very precise patterns of light on the silicon using very high frequency light to activate photoresist, and then etching away the silicon that isn't protected by the photoresist. this doesn't actually produce features as small as the fins, so there are a lot of tricky techniques, like doing this patterning + etching once, then growing a layer of some other material on top, then etching again to leave only the very narrow sidewalls that grew around the original feature, then etching again using the sidewalls as the pattern. https://en.wikipedia.org/wiki/Spacer_patterning https://en.wikipedia.org/wiki/Spacer_patterning it really is amazing - reliably writing tiny structures on stones with light.
- andrewf 5y agoIf you have an hour, this decade-old video blew my mind: "Indistinguishable from Magic: Manufacturing Modern Computer Chips" https://www.youtube.com/watch?v=NGFhc8R_uO4 https://www.youtube.com/watch?v=NGFhc8R_uO4 HN thread from a couple years ago: https://news.ycombinator.com/item?id=16175949 https://news.ycombinator.com/item?id=16175949