25 Oct
2025
25 Oct
'25
1:39 p.m.
On Oct 25, 2025, at 2:53 PM, dwight via cctalk
<cctalk(a)classiccmp.org> wrote:
So much has changed since then. First was the doped gemanium junctions. Silicon waited
until photo and surface defusion started happening. The opening of PMOS and NMOS was when
we truly moved from the descrite devices to the complex circuits. The combining of P and N
doping brought in CMOS. It was slow but great for low power application. Then the mask
creation of self aligned gates brought the speed always waiting in CMOS. The art of making
mask that understand the wave nature of light, do the optical corrections need for even
tinier dementions. Now UV light is pushing the size of the tiniest transistors.
"UV" indeed. In particular, what's called "Extreme UV" -- 13 nm,
almost in what is typically considered X-ray wavelengths. That is the territory of ASML
lithography machines, a world where no other company has gone. The details are quite
mindboggling. The entire optical path has to be in vacuum, and the optical elements are
mirrors. The precision involved is vastly greater than anything else in history. For
example, mirrors accurate to a few nanometers (vs. 100 nm or so for typical telescope
mirrors). Positioning accuracy of the wafer X/Y carriage to 10 nm, with movement in a
fraction of a second from one die position to the next. Temperature control to insanely
small values. And so on. I spent a bit of time reading their technical descriptions; I
know just enough about precision mechanical engineering and optics to get my mind severely
blown from seeing what these people do.
I remember at one time IBM was building a synchrotron so they could generate coherent
X-rays for lithography. That never went anywhere as far as I know. ASML doesn't do
that, they use exotic laser technology instead.
paul