Building a Denser Chip

Building a Denser Chip
The more memory and capacity a semiconductor chip has, the more wires and transistors it needs. But packing an ever larger number of wires and transistors onto the same size silicon wafer is an increasingly difficult and expensive proposition. The latest effort to decrease the distance between wires and other features on chips, called extreme ultraviolet lithography, uses a slow-moving machine that costs about $50 million to make. But now, MIT researchers have developed a technique that can refine the patterns of computer chips quickly and
cheaply. Physicist Mark Schattenburg and mechanical-engineering graduate student Chih-Hao Chang used a nano ruler, recently invented by Schattenburg, that lets them rapidly print precise lines over a large area. They combined that with a novel process that transferred the pattern to the right layer of the silicon wafer, allowing them to etch one pattern on a chip, shift the chip incrementally, and then etch again. After repeating this four times, the scientists produced an even grid of lines that were only 25 nanometers apart—versus today’s standard
65 nanometers—with relatively minimal fabrication costs. Such a process, Schattenburg says, has potential applications for everything from semiconductors to solar-cell production.