Researchers at Princeton University this week reported that they have found a way to literally melt away miniscule defects in computer chips, a discovery that could help manufacturers build more powerful processors.
As chips get smaller and smaller, tiny defects in shapes, lines and dots that are etched into them can ruin performance. If the nanostructures aren't straight, thin and tall in integrated circuits, for example, it could cause current leakage and voltage fluctuation.
"These chip defects pose serious roadblocks to future advances in many industries," said Stephen Chou, Princeton's Joseph C. Elgin Professor of Engineering, in a statement. Chou worked with graduate student Qiangfei Xia on the research project.
By getting rid of the tiny flaws, chip makers could create even smaller and more powerful processors, which, in turn, could mean smaller and more powerful devices.
Chou and Xia's effort did not focus on finding ways to create chips with no flaws, but on ways to automatically erasing existing ones. The process, which the inventors call Self-Perfection by Liquefaction, is designed to melt the structures on the chip in a fraction of a millionth of a second -- just long enough for the resulting flow of liquid to be guided so it re-solidifies into the proper shapes, according to a university document.
The researchers use a pulse of light from a laser similar to the ones used in laser eye surgery, because it heats only a thin top layer of the flawed structures, which are made of semiconductors and metals, and causes no damage to whatever is beneath it. They designed the pulse so it melts only semiconductor and metal materials and leaves other parts of the chip untouched, the university reported.
Chou also noted that he placed a thin quartz plate on top of the melting structures to guide the liquid flow. The plate prevents the molten structure from widening, while keeping its top flat and sides vertical. In one experiment, it made the edges of 70 nanometer-wide chromium lines more than five times smoother, according to Chou.
"We are able to achieve a precision and improvement far beyond what was previously thought achievable," said Chou. "What we propose... is a paradigm shift. Rather than struggle to improve fabrication methods, we could simply fix the defects after fabrication. And fixing the defects could be automatic -- a process of self-perfection."
The next step for the Princeton researchers will be to try out this new technique on 8-in. wafers, the university reported.
The research was published in the May 4 issue of Nature Nanotechnology.