[citation][nom]agnickolov[/nom]Current production uses 300mm wafers, so yes - it's definitely bigger, 2.25 times bigger in fact (1.5 times the diameter squared)[/citation]
The area of a circle is pi x (radius) squared
So basically we go from 221,841mm of area to 499,142mm (2.25 times bigger) your math was correct, just not the formula. This number is a bit deceptive however, since chips shot on the edge are often incomplete and more likely to suffer defects, so increasing the overall circumference will increase the number of defects, but it's worth it. It was ten years ago that 300mm was in development and in the early 2000's we transitioned from 200mm (eight inch wafers), this was very important to increasing the total production volume in order to keep up with the exponential increase in development costs. 22nm will push the border of current generation immersion lithography, and will most likely cross over to EUVL (Extreme UV Lithography) at the die shrink from 22nm to 16~15nm which should happen some time in late 2012 or early 2013. EUVL is still too expensive and has a high rate of defects, so we probably won't see any products from this process until 2013 in either case. Double-patterning and improvements in immersion lithography technology will probably be extended until 450mm wafers are proven reliable. This is the only way to improve semiconductor nodes while reducing prices.