By Tyler Irving
Posted January 2011
There’s a new tool in the quest to design ever-smaller silicon circuits: the microwave oven. Researchers at the University of Alberta’s National Institute of Nanotechnology are using microwave heat to speed up the self-assembly of certain block copolymers. The ability to do these reactions quickly offers an alternative method of making the intricate templates used in semiconductor manufacturing.
Computer chips are typically made by photolithography. Light is used to burn patterns into polymer films which then serve as templates for etching silicon. Certain features in these patterns can be as thin as 50 nanometres. But the process is becoming prohibitively expensive as scientists try to make even smaller features with more finely focused light.
Block copolymers bypass light entirely. These mixtures of two different plastics self-assemble into intricate patterns in much the same way as the two complimentary strands of a DNA molecule. They’ve been shown to be capable of producing the intricate features in chip templates, but the problem is speed. “The time in which these things will spontaneously self-assemble normally takes hours to days at high temperature,” says Jillian Buriak, lead researcher on the project. “We do it in a microwave in a minute.”
Not only is the process fast and cheap, but Buriak believes it could make even smaller templates, right down to the limits of nature. “People are talking about sub-10 nanometre patterns using self-assembly,” she says. “A nanometer is about four to five atoms. At a certain point, you’re just coming up against numbers of atoms. It’s amazing.”
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