Improved etching techniques have been making their way into the science journals of late.
Earlier this month, researchers from the University of Pittsburgh published their work in using DNA origami to both promote and inhibit the etching of SiO2 at the single-molecule level.Now researchers at Argonne Center for Nanoscale Materials and Energy Systems Division have published two studies on a technique they have developed called sequential infiltration synthesis (SIS), which builds on long-standing lithography techniques but could be a real breakthrough in the field, according to the researchers. The research, which was led by Seth Darling and published in two journals—Journal of Materials Chemistry and the Journal of Physical Chemistry C—involved developing a way by which to strengthen the delicate resist film to the extent that it no longer needs the intermediate mask.
What this translates into is a capability not only to circumvent all the complexities brought on by the use of an intermediate mask, but also to etch a pattern with greater depth and fidelity.
The SIS technique involves the controlled growth of inorganic materials with polymer films that can be built into complex, 3-D structures.
“It's possible we might be able to create very narrow features well over a micron deep using only a very thin, SIS-enhanced etch mask, which from our perspective would be a breakthrough capability," says Darling.The researchers are looking at expanding the capabilities of the technique by combining SIS with block polymers to make features even smaller than those possible with e-beam lithography. "This opens a wide range of possibilities," said Argonne chemist Jeff Elam, who helped create the process. "You can imagine applications for solar cells, electronics, filters, catalysts—all sorts of different devices that require nanostructures, but also the functionality of inorganic materials."
Dexter Johnson is a contributing editor at IEEE Spectrum, with a focus on nanotechnology.