For example i notice that the latest chips are 3 nm & below, & over the last decade i’ve seen it shrink little by little. What is it about this process that more money needs to be poured into each die shrink, & why couldn’t we just jump from 90nm to 3nm instead pf 65nm etc etc?
In: Engineering
It takes lots of research how to make such chips. You need to engineer a method to actually carve such extremely fine structures into silicon, depositing some other elements in very controlled doses, and so on.
This process for example involves making and focusing light (or electrons) with very high precision. Light cannot really act with much more precision than roughly its wavelength. So to make smaller and smaller structures we need light to be of a rather short wavelength, entering into UV or even x-ray territory.
Creating consistent and _coherent_ UV light is already not so easy. At some point even lenses don’t work anymore for various reasons. X-rays in particular cannot really be treated as visible light at all, they bend around every corner and are not really reflected the way mirror does, regardless how flat and perfect a surface is. Instead they go everywhere and things get complicated.
As mentioned we can sometimes instead use electron beams. But this just adds new issues. We have to replace any lenses and mirrors by electric and magnetic fields and such!
Other aspects that had a lot of development are for example the _architecture_ (how and what things are arranged on the chips) and the general abilities (multiple cores and threads, graphics support on some CPUs, tensor and other such developments on graphics card, …). Those all aren’t just minor changes but are extremely complex to optimize.
With the sizes we are now at (3 nm is ~30 atoms in diameter!) it even matters that electrons tunnel by quantum “magic” by the way.
The above and many other **technologies simply had to be invented first, which takes time**. It is also easier to slowly improve and thus test each progressive step without changing too much else. For example Intel alternates: each second generation decreases in size, while the other iterations focus on the architecture. It would make little sense to wait literally 10 or 20 years until we finally decrease in size, chip factories have to be refined and improved long before that to keep up with developments.
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