"Sweet" microchip, new technology can use sugar to achieve curved surface printing

Using sugar and corn syrup, researcher Gary Zabo transferred the word "NIST" in gold letters onto human hair. Image source: National Institute of Standards and Technology

Can regular table sugar transfer microchip patterns to new and unconventional surfaces? In the latest issue of the journal Science, scientists at the National Institute of Standards and Technology (NIST) report a method of using sugar to transfer onto almost any common surface. Opening up new materials and microstructures offers new possibilities.

Semiconductor chips, micropatterned surfaces and electronics all rely on microprinting, a process in which precise but tiny patterns between a millionth and a billionth of a meter wide are placed on surfaces to give them new properties. process. Traditionally, these tiny patterns of metals and other materials are printed on flat silicon wafers. But as the possibilities for semiconductor chips and smart materials expand, these complex, tiny patterns will need to be printed on new, non-traditional, non-planar surfaces. Printing patterns directly on these surfaces is tricky, so the scientists transferred the prints, but precise transfer to more common surfaces of arbitrary curvature remains elusive.

Researchers found that a simple combination of caramel and corn syrup can do just that. When dissolved in a small amount of water, this sugar mixture can be poured onto a flat surface in miniature patterns. Once the water evaporates, the candy hardens and can be lifted with the pattern embedded in it. The patterned candy is then placed on the new surface and melted. The combination of sugar and corn syrup maintains a high viscosity as it melts, allowing the pattern to maintain its alignment as it flows over curves and edges. The sugar is then washed away with water, leaving only the pattern.

Using this technology, called Reflow Driven Flexible Transfer (REFLEX), microcircuit patterns can be transferred like a template, allowing scientists or manufacturers to etch and fill the materials they need in the right places. Patterned materials can be transferred from the original chip onto fibers or microbeads for potential biomedical or microrobotic research, or onto sharp or curved surfaces in new devices.

Using REFLEX, researchers were able to imprint the word "NIST" in tiny gold letters on the tips of pins and on strands of human hair. In another example, 1-micron-diameter disks were successfully transferred onto the fuzz fibers of milkweed seeds. In the presence of a magnet, the magnetically printed fibers reacted, indicating that the transfer had been successful.

Use syrup to transfer microchip patterns? This imaginative approach is reminiscent of my country's traditional folk handicraft-sugar painting. It has to be said that the two have similar approaches but the same purpose. Of course, the patterns transferred by the above-mentioned research institute are only one millionth to one billionth of a meter wide. In terms of scale alone, they are many times finer than the sugar paintings that were once sold on the streets. Sugar is the most common ingredient in daily life. Applying it to cutting-edge research on microcircuit and semiconductor chips has achieved a seamless connection between "down-to-earth" and "high-end". This attempt to break the inherent thinking framework is worth it. Learn from.