Credit: © 2007 IBM

IBM has introduced a self-assembly process into chip manufacture — a first for the semiconductor industry. In a press release1, the company reports that the new chips consume 15% less energy than conventional devices, and that electrical signals can travel 35% faster in the new chips. The company says that the improvement in wiring performance is equivalent to two generations of Moore's law being acheived in a single step.

Dan Edelstein and co-workers exploit self-assembly to create air gaps — which are actually regions of vacuum — that act as insulators between the copper wires on the chip. As chips have become smaller, the wires inside them have become closer, making insulation more difficult. At first, semiconductor companies tried to solve this problem by introducing new materials with better insulating properties, but these materials tended to be fragile.

The IBM team has now developed a completely new solution that involves pouring what the press release describes as "the right mix of compounds" onto a silicon wafer that has already been patterned with wires and then baking it to form a carbon silicate glass that contains trillions of holes. The holes are uniform in size with a diameter of just 20 nanometres, which is five times smaller than is possible with lithography. The glass is then removed to leave the vacuum gaps between the wires.

The new process, which has been patented, has already been integrated into a manufacturing line at IBM's East Fishkill site in New York state, and is expected to be included in all the company's production lines by 2009.