Johns Hopkins researchers have discovered new materials and a new process that could make smaller, faster and more affordable microchips used across all modern electronics. The scientists discovered how to create circuits so small they’re invisible to the naked eye using a process that is both precise and economical for manufacturing.
image: A 10 cm silicon wafer with large visible patterns created using B-EUV lithography
The findings are published in the journal Nature Chemical Engineering.
“Companies have their roadmaps of where they want to be in 10 to 20 years and beyond,” said Michael Tsapatsis, a Bloomberg Distinguish Professor of chemical and biomolecular engineering at Johns Hopkins University. “One hurdle has been finding a process for making smaller features in a production line where you irradiate materials quickly and with absolute precision to make the process economical.”
The advanced lasers required for imprinting on the miniscule formats already exist, Tsapatsis added, but researchers needed new materials and new processes to accommodate ever smaller microchips.
Microchips are flat pieces of silicon with imprinted circuitries that execute basic functions. During production, manufacturers coat silicon wafers with a radiation-sensitive material to create a very fine coating called a “resist.” When a beam of radiation is pointed at the resist, it sparks a chemical reaction that burns details into the wafer, drawing patterns and circuitry.
However, the higher-powered radiation beams that are needed to carve out ever-smaller details on chips do not interact strongly enough with traditional resists.
Previously, researchers from Tsapatsis’s lab and the Fairbrother Research Group at Johns Hopkins found that resists made of a new class of metal-organics can accommodate that higher-powered radiation process, called “beyond extreme ultraviolet radiation” (B-EUV), which has the potential to make details smaller than the current standard size of 10 nanometers. Metals like zinc absorb the B-EUV light and generate electrons that cause chemical transformations needed to imprint circuit patterns on an organic material called imidazole.
This research marks one of the first times scientists have been able to deposit these imidazole-based metal-organic resists from solution at silicon-wafer scale, controlling their thickness with nanometer precision.
image credit: Xinpei Zhou, Johns Hopkins University