Moore’s law at the extremes

Predictions that Moore’s law — which states that the number of components fabricated on a chip will double every 18 months — is about to come up against a physical ‘red brick wall’ seem perennial. But optical lithographers have so far confounded the prophets of doom, managing to etch ever finer details onto Si. Now, though, the limits are truly in sight, leaving chip makers wondering what technology can carry them forward towards the billion-transistors-on-a-chip mark and whether a successor will finally be needed for complementary metal oxide semiconductor (CMOS). The likely answer to these questions may appear surprising.Photolithography is still working wonders for the chip industry. Not so long ago, moving from the 248 nm laser wavelength standard and the 120 nm features that it can routinely produce to a 193 nm laser wavelength and 90 nm features seemed a big challenge. Yet, even as chip makers adopt this new standard and consider enhancing it through two or three generations to produce features of 60 nm and less, lithographic tool makers are starting to gear up for 157 nm deep ultraviolet (DUV) technology as the next step. Predictions are that 10 GHz microprocessor clock speeds, compared with the present 2.8 GHz state-of-the-art, should be achieved by 2006.