20/20 Foresight

Chip Making: To 10 GHz and Beyond

Extreme ultraviolet lithography

What is it? A way to make processors that are up to 100 times faster than today's chips. What's cool? Even Moore's Law eventually gets trumped by the laws of physics. In a few years, the current method of packing ever greater numbers of transistors onto a chip will hit a wall. But a technology called Extreme Ultraviolet Lithography may break that barrier. Intel estimates that EUVL chips will boast 400 million transistors--about ten times more than the Pentium 4's 42 million. When's it coming? In three to five years. What's the catch? Software that's capable of taking advantage of all this processing muscle is nowhere in sight. Impact meter: 8

How It Works: Chip makers create today's processors by focusing ultraviolet light--first through a mask (which acts like a photograph negative) and then through quartz lenses--to carve circuits one-fourth the size of the mask into a silicon wafer. Chip makers have made circuits smaller and faster by using light with progressively shorter wavelengths. But when light waves get too short, they are absorbed by the lenses, as well as by the air. The solution? In a vacuum, use specially constructed concave mirrors, instead of lenses, to reflect and focus extreme ultraviolet light.

1. A high-energy laser is concentrated on a jet of xenon gas, creating plasma.

2. The xenon plasma emits a powerful glow of extreme ultraviolet light with a wavelength of 13 nanometers--one-thirtieth the wavelength of violet visible light.

3. A condenser gathers the light and directs it toward the mask, which contains a stencil image of the circuit pattern on a mirror.

4. The image of the circuit pattern reflects off the mask mirror and then off a series of four to six concave mirrors, which reduce and sharpen the image and then project it onto a silicon wafer coated with a light-sensitive material (called a resist).

5. Wherever the light hits it, the resist hardens, shaping the circuit. A chemical wash removes the unhardened resist material, exposing the silicon beneath.