Optical lithography is the secret sauce in the fabbing technology that makes the chips inside your computer, and a clever bunch at the University of California, Berkeley have worked out a new adaptation of the tech to produce chips that could be ten times more detailed. It basically combines a hard-disk-alike spinning platter and scanning head with a metal lens to focus UV light onto smaller spots: by rotating a chemically treated silicon wafer beneath the head, you can achieve far more precise chips than using a photo mask.
The metal lens is the key: it’s in fact a plasmonic lens, that achieves a smaller “focussed” spot of UV light than is possible with the diffraction limits of normal optics. The photoresist surface of the chip needs to be very close beneath the lens to work, hence the choice of the “flying head” arm—much like that in a conventional hard drive. This keeps the lens around 20nm above the silicon wafer, using aerodynamic forces between the spinning wafer and the head.
Why do we care about this? Conventional photolithography can achieve chip details down to a size of about 35nm, but with this technique the size could shrink to as small as 5nm. And it’s fast, and doesn’t require million-dollar lithography photomasks. Plus as well as denser, more powerful computer chips the technique could even be modified to create optical data storage systems with fantastic amounts of capacity. Clever stuff, and might keep Moore’s law ticking over for a while yet.
via Gizmodo by Kit Eaton on 10/23/08