4 ms·

Not “layers”, but “features”. 3nm is basically a pixel size for chip schematics, it doesn’t mean that they draw 1px features with it.

samstave 4y ago
This was always my understanding is that the litho(?) mechanism can "print" in 3nm resolution, which allows the overal scaling of all features to be based on this "pixel" resolution. I was dumbfounded when even hearing about 14NM YEARS before it was a thing (I also got to see 64-core concepts at intel in ~1999 or so) 3nm is mind boggling amazing. Whatever happened to "voxels" (before the graphics term, intel was creating "voxels" that were used to use light to transfer vertically between layers... but I stopped following CPU arch years ago.
- agar 4y ago
  hah, I remember when "submicron technology" was the bleeding edge of chip design. :-) https://cordis.europa.eu/project/id/554 https://cordis.europa.eu/project/id/554
ajross 4y ago
It's not even that. Nothing in a modern process node is as small as the node size, and in fact with modern processes it's not even close. I just checked, and per some reference on wikipedia TSMC 3nm's metal pitch is expected to be 24nm (so, ~12nm wide metal "wires" on the lowest level of interconnect are the smallest things you'll see on a picture). What's been happening is that fabs have been exploiting more and more tricks to increase transistor density while still using the larger feature sizes. So flat transistors became finfet's, increasing their gate area and allowing chips to use fewer of them for the same silicon area, etc... So read "3nm" as "a process with the same transistor density as you would expect had some ancestral ~90nm process been shrunk by a factor of 30".
- dibujante 4y ago
  Thanks, this is a great explanation. It seems like these "nm" indicators are much like measuring a car's power in "horsepower". It is certainly measuring something real but its connection to actual horses has long since atrophied.

samstave 4y ago

This was always my understanding is that the litho(?) mechanism can "print" in 3nm resolution, which allows the overal scaling of all features to be based on this "pixel" resolution. I was dumbfounded when even hearing about 14NM YEARS before it was a thing (I also got to see 64-core concepts at intel in ~1999 or so) 3nm is mind boggling amazing. Whatever happened to "voxels" (before the graphics term, intel was creating "voxels" that were used to use light to transfer vertically between layers... but I stopped following CPU arch years ago.

agar 4y ago
hah, I remember when "submicron technology" was the bleeding edge of chip design. :-) https://cordis.europa.eu/project/id/554 https://cordis.europa.eu/project/id/554

ajross 4y ago

It's not even that. Nothing in a modern process node is as small as the node size, and in fact with modern processes it's not even close. I just checked, and per some reference on wikipedia TSMC 3nm's metal pitch is expected to be 24nm (so, ~12nm wide metal "wires" on the lowest level of interconnect are the smallest things you'll see on a picture). What's been happening is that fabs have been exploiting more and more tricks to increase transistor density while still using the larger feature sizes. So flat transistors became finfet's, increasing their gate area and allowing chips to use fewer of them for the same silicon area, etc... So read "3nm" as "a process with the same transistor density as you would expect had some ancestral ~90nm process been shrunk by a factor of 30".

dibujante 4y ago
Thanks, this is a great explanation. It seems like these "nm" indicators are much like measuring a car's power in "horsepower". It is certainly measuring something real but its connection to actual horses has long since atrophied.