The Anatomy of a Z80 Gate (2014)
devic.us
devic.us
Moore's law wouldn't have had the constant march forward it had for 40 years, if shrinking transistors smaller wasn't just the "simple" matter each time of either developing a slightly more accurate projection system; or discovering a quicker-reacting, less-runny, more-durable photoresist chemical.
We're running into the limits of this approach now, and having to look for other interesting tricks, but there was a lot of low-hanging fruit in photolithographic precision, there for us to pluck, and pluck, and pluck, year after year.
As i grow older i find myself recognizing similar trends in a number of fields. You have a initial slow takeoff period where basic science has to be figured out. Then you have a steep climb as that science unlocks a bunch of iterative refinements on the concept. And then you find yourself at a plateau as new iterations become expensive and complex.
[1] http://radar.oreilly.com/2007/11/its-not-exponential-its-sig...
I've been reading Vaclav Smil. His log and semilog plots tell stories.
But isn't the "wall" we are hitting the result of quantum tunneling(leaking) and less about the photolithography process or am I misunderstanding your comment?
The currently used light wavelength is many times larger than the features they make with it, and the lamps for the next smaller wavelength have serious issues of not being bright enough as they are ~80w now and need to be ~200w, being blocked by air but they cant run in a vacuum because immersion lithography and other parts of the process don't work in vacuum and finally they are only reliable enough for lab use.
In other places they are running out of atoms to take away (eg: some parts are 15 atoms thick and at 14 atoms thick they no longer have the properties needed). In some cases they are stretching atoms farther apart to make them work better with the few they have (see strained silicon).
Another part is heat rejection from the silicon as while each transistor is more efficient and smaller on a individual basis, you have much more of them. This is why modern processors, when running a single thread workload, will shut off a core to spend its heat budget on running that 1 core faster or a big difference between a phone and tablet CPU is the amount of power dissipation rather than the silicon itself.
I'd also like to say kudos to the author. Great write up.