[prewett]

I could be wrong, but I think optical processors would have serious diffraction problems with a 7 nm feature size, since the wavelength of blue light is somewhere around 300 nm.

As far as fabrication, one problem is that obviously you aren't using visible light to etch features on your wafers. The x-rays must be fun to work with... Not to mention, your photoresist would have to resist x-rays. Getting x-ray-resisting photoresist on and off your wafer must be tricky. Since 7 nm is about the size of several atoms, your wafer probably needs to be almost perfectly pure, which can't be easy, either.

[pjc50]

It's not xrays, it's "extreme ultraviolet" (EUV), plus diffraction-based multiple patterning. http://www.extremetech.com/computing/160509-seeing-double-ts...

(tldr: 193nm light works down to 28nm lambda; progress requires moving further into UV and/or use immersing in liquid with different refractive index)

[BinaryIdiot]

Hmm yeah I have no idea, I mostly read this which really intrigued me but I don't really understand all of the technology and science behind it http://www.intel.com/pressroom/archive/releases/2010/2010072...

I had always gotten the impression that even if it they couldn't get as small the impact of less heat and the ability to cross beams could allow them to be denser. But like I said I don't really know what I'm talking about :)

[pjc50]

You can't cross light beams at 7nm, if you had a "crossroads" structure" it would simply diffract round the corner and exit at all three other points.