Double-laser approach makes one thin line
Erasing and stenciling offers new approach for nanolithography
Michelangelo couldn’t have chiseled David’s features with the edge of a backhoe. But just such a challenge faces scientists working in the infinitesimally small world of nanolithography, the ultratiny writing used to make computer chips, solar cells and other devices. Now three reports, published online April 9 in Science, introduce new methods to erase and stencil patterns, putting a finer point on the tools used to sculpt and write in the incredibly shrinking nanoworld.
The research “could spawn all kinds of interesting ideas and new approaches,” comments Greg Wallraff of the IBM Almaden Research Center in San Jose, Calif. “This is really interesting science.”
Current nanolithography techniques use ultraviolet light to etch patterns and images that can be used, for example, to inscribe circuitry on computer chips. Nanolithography is a precise form of photolithography, which shares many fundamentals with regular photography — light is projected through a lens onto a material that reacts upon exposure. For crafting tiny objects or masks used for imprinting circuitry, the material is often a liquid compound called a monomer, which turns into a hardened, repeating version of itself, a polymer, when exposed to light.
Progress has been made in using smaller and smaller wavelengths of light to create the printed patterns, but now that approach is limited in part because of how light behaves at such short wavelengths. And these techniques also require enormous, expensive lenses.