IBM hails nano chip-making method

By Jonathan Amos
BBC News Online science staff

Polymer template: The dark circular holes in the stencil are 20 nanometres in diameter

IBM has trumpeted a nanotech method for making microchip components which it says should enable electronic devices to continue to get smaller and faster.

Current techniques use light to help etch tiny circuitry on a chip, but IBM is now using molecules that assemble themselves into even smaller patterns.

Because the technology is compatible with existing manufacturing tools, it should be inexpensive to introduce.

IBM says it hopes to pilot the nanotech process in about three to five years.

Wash and fill

The company's researchers used the novel approach to make part of a device that acts as a type of flash memory, which retains recent information when an electronic gadget is turned off.

Such memory is commonly found in handheld computers, mobile phones and digital cameras.

IBM said the critical features of the semiconductor device were created using polymer molecules that quite naturally arranged themselves into hexagonal patterns that were "smaller, denser, more precise, and more uniform than can be achieved using conventional methods like lithography".

At the moment, for example, microchip circuitry is put on silicon wafers using a lithographic process in which the image of the design of how the wires are to be laid out is first projected on to the prepared wafers.

Chemical washes then cut out the spaces according to this template that make channels which will be filled to make the circuit features - transistors, and the like.

By all standards

With the new technique, it is the polymer patterns that provide the initial stencil - in this instance, for the crystalline array used to make the flash memory.

Scientists say lithography is approaching its limits because of the difficulties of focussing light at very small scales - and new technologies are required if computer power is to continue to increase at its present rate.

IBM believes nanotechnology - engineering with atoms and molecules in the realm of just billionths of a metre - is one possible way forward.

"We are patterning at 20-nanometre dimensions and, depending on who you talk you, that's about 10 times smaller than standard lithography," Chuck Black, a researcher on the IBM project, told BBC News Online.

While IBM used the new process to build a tiny memory device, Black underlined the technology could be useful for making microprocessor components, which are more complex.

Two are better

Already, he said, the company was looking at how self-assembly molecules could be used to increase the capacitance of certain chip components, something that would be important as processors ran at higher speeds.

And Black stressed the beauty of the new approach was that it could be incorporated quite easily into the current chip-making process.

"We've got the best of both worlds here," he said.

"We've taken self-assembly materials and combined them with how we normally make semiconductor devices, to produce structures that are patterned on a finer-length scale than you would find in just lithography on its own."

Kathryn Guarini, Black's co-researcher, will report the development in a paper at the International Electron Devices Meeting in Washington on Tuesday.