Melting microchip defects may overcome manufacturing limitations

Termed Self-Perfection by Liquefaction (SPEL), the technique has been developed by engineers at the Princeton University, and works by melting away tiny defects in the patterns etched on microchips.

By enabling more precise shaping of microchip components, the engineers expect to dramatically improve chip quality without increasing fabrication cost.

Researchers have traditionally approached chip defects by trying to improve the microchip fabrication process.

However, such an approach eventually reaches fundamental physical limits to do with random behaviour of the electrons and photons that are used like chisels to carve out the microscopic features on a chip.

This effect becomes pronounced at very small scales and limits the accuracy of component shapes.

"What we propose instead is a paradigm shift," said electrical engineer Stephen Chou, the Joseph C. Elgin Professor of Engineering at Princeton University.

“Rather than struggle to improve fabrication methods, we could simply fix the defects after fabrication,” he said. “And fixing the defects could be automatic -- a process of self-perfection.”

The Princeton method works by melting structures on a chip with a carefully-designed light pulse from an excimer laser, and guiding the resulting flow of liquid so that it re-solidifies into the desired shapes.

This is possible because natural forces acting on the molten structures, such as surface tension -- the force that allows some insects to walk on water -- smooth the structures into geometrically more accurate shapes.

"Regardless of the shape of each defect, it always gets fixed precisely and with no need for individual shape measurement or tailored correction," Chou said.

The research has been supported by the U.S. Defense Advanced Research Projects Agency (DARPA) and the Office of Naval Research. Already, several leading semiconductor manufacturers have expressed keen interest in the technique, Chou said.

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