Self-assembling computer chips
The features on computer chips are getting so small that soon the process used to make them, which has hardly changed in the last 50 years, won’t work anymore. One of the alternatives that academic researchers have been exploring is to create tiny circuits using molecules that automatically arrange themselves into useful patterns. In a paper that appeared Monday in Nature Nanotechnology, MIT researchers have taken an important step toward making that approach practical.Currently, chips are built up, layer by layer, through a process called photolithography. A layer of silicon, metal, or some other material is deposited on a chip and coated with a light-sensitive material, called a photoresist. Light shining through a kind of stencil — a “mask” — projects a detailed pattern onto the photoresist, which hardens where it’s exposed. The unhardened photoresist is washed away, and chemicals etch away the bare material underneath.The problem is that chip...