Princeton engineers low-cost technique for patterning microchips

Princeton engineers have developed a simple, low cost technique for making ultra-small grooves on microchips - a key part of many modern technologies.

Washington, Sept 3 : Princeton engineers have developed a simple, low cost technique for making ultra-small grooves on microchips - a key part of many modern technologies.

The technique results in the self-formation of periodic lines, or gratings, separated by as few as 60 nanometers - less than one ten-thousandth of a millimetre - on microchips.

Scientists say features of this size have many uses in optical, biological and electronic devices, including the alignment of liquid crystals in displays.

"It's like magic. This is a fundamentally different way of making nanopatterns," said electrical engineer Stephen Chou, the Joseph C. Elgin Professor of Engineering at Princeton.

Firstly, a thin polymer film is painted onto a rigid plate, such as a silicon wafer. Then, a second plate is placed on top, creating a polymer sandwich that is heated to ensure adhesion. Finally, the two plates are pried apart.

As the film fractures, it automatically breaks into two complementary sets of nanoscale gratings, one on each plate. The distance between the lines, called the period, is four times the thickness of the film.

According to Chou, the process, called fracture-induced structuring, is remarkably easy compared to traditional fabrication methods, which typically use a beam of electrons, ions, or a mechanical tip to "draw" the lines into a surface.

"It's remarkable - and counterintuitive - that fracturing creates these regular patterns," said chemical engineering professor and dean of Princeton's graduate school, William Russel.

The team have now filed a patent for their process.

The research appears online in the September 2 issue of Nature Nanotechnology.

ANI