For decades, computers have grown more powerful because chipmakers have been able to make ever-smaller transistors, allowing them to cram more onto a single chip. That steady march has always depended on optics—shorter wavelengths of light allowed chipmakers to draw smaller lines for circuit paths, which then can be closer together. It has become increasingly harder, however, to reach the high resolutions needed for ever-tinier features.
The answer, or at least part of it, may lie not with optics at all, but with chemistry. Researchers in both industry and academia are trying to perfect a process that would let chemicals arrange themselves into tiny lines to serve as a pattern for the circuits. The lines and spaces in most chips now are on the order of 40 nanometers (nm) wide, but are expected to drop to less than 10 nm within a few years.