I searched google and found absolutely nothing, so I'm not sure it's even true...
however if it is, I'd say it would be a result of the transistors they're going to use (I think they're going to use the Silicon-Germanium transistors they're co-developing with IBM - which IBM got to 350GHZ at room temperature)
plus, they're altering the shape of the transistors to increase surface area (without increasing footprint size)