It is a hoax, you can read more at Snopes and here.
But to add a bit of info, the story became popular in 1998, so the scale they would be working in was at best 250 nano-meters, so the picture would have been taken with an electron scope.
Here is the original picture:
The image is a clever digital manipulation of an image that appears on
the cover of Darrell Duffie's book
...
It's a clever prank playing off the idea that a couple of Apple
aficionados could surreptitiously sneak an anti-Bill Gates message
onto the world's most popular CPU, where it could be seen only through
a powerful microscope, but it's a hoax.
Here's another link with more information.
Semiconductor manufacturing improvements by year:
10 µm — 1971
3 µm — 1975
1.5 µm — 1982
1 µm — 1985
800 nm (.80 µm) — 1989
600 nm (.60 µm) — 1994
350 nm (.35 µm) — 1995
250 nm (.25 µm) — 1998
180 nm (.18 µm) — 1999
130 nm (.13 µm) — 2000
90 nm — 2002
65 nm — 2006
45 nm — 2008
32 nm — 2010
22 nm — 2012
Any of a number of semiconductor materials can be and are used, indeed the first transistor was actually a Germanium (Ge) transistor. the real reason why Si is so dominant comes down to 4 principal reasons ( but #1 is the primary reason):
1) It forms an oxide that is of very high high quality, seals the surface with very few pin holes or gaps.
- this allows gap MOSFET to be more easily made as the SiO2 forms the insulating layer for the Gate,
- SiO2 has been called the chip designers friend.
2) It forms a very tough Nitride, Si3N4 Silicon Nitride forms a very high bandgap insulator which is impermeable.
- this is used to passivate (seal) the die.
- this also used to make hard masks and in other process steps
3) Si has a very nice bandgap of ~ 1.12 eV, not too high so that room temperature can't ionize it, and not so low that it has to high leakage current.
4) it forms a very nice gate material. Most modern FET's used in VLSI (up until the latest generations) have been called MOSFET but in actual fact have used Si as the gate material. It turns out that it is very easy to deposited non-crystalline Si on surfaces and it is easily etched to great precision.
Basically the success of Si is the success of MOSFET, which with scaling and extreme integration has driven the industry. Mosfet's are not so easily manufactured in other material systems, and you can't drive the same level of integration in other semicondcutors.
GeO2 - is partially soluble
GaAs - does not form a oxide
CO2 - is a gas
Semiconductors are used because with selective contamination (called dopants) you can control the properties of the material and tailor it's operation and operational mechanisms.
Best Answer
The "reticle limits" you allude to refer to the area over which the optics can maintain the highest resolution. This is one of the things that limits the size of a conventional chip.
Normally, when you step the reticle to the next chip position, you don't care so much about the exact alignment between the two adjacent chips, because you aren't trying to make connections between them. The stepper just needs to be accurate enough so that you don't waste a lot of area for the dicing channels.
But if you DO want to make connections between "chips" using overlapping images, there's nothing stopping you from coming up with a relaxed set of design rules for those connections that takes into account the accuracy of the stepper.
There are other ways to make such connections as well. In the worst case, you could always use your wire bonder to make them. And a FIB (focused ion beam) machine can be used to post-process a wafer to add or remove connections.