Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Sharpening the lines

New advance could lead to even smaller features in the constant quest for more compact, faster microchips.

The microchip revolution has seen a steady shrinking of features on silicon chips, packing in more transistors and wires to boost chips’ speed and data capacity. But in recent years, the technologies behind these chips have begun to bump up against fundamental limits, such as the wavelengths of light used for critical steps in chip manufacturing.

Now, a new technique developed by researchers at MIT and the University of Utah offers a way to break through one of these limits, possibly enabling further leaps in the computational power packed into a tiny sliver of silicon. A paper describing the process was published in the journal Physical Review Letters in November.

Postdoc Trisha Andrew PhD ’10 of MIT’s Research Laboratory of Electronics, a co-author of this paper as well as a 2009 paper that described a way of creating finer lines on chips, says this work builds on that earlier method. But unlike the earlier technique, called absorbance modulation, this one allows the production of complex shapes rather than just lines, and can be carried out using less expensive light sources and conventional chip-manufacturing equipment. “The whole optical setup is on a par with what’s out there” in chip-making plants, she says. “We’ve demonstrated a way to make everything cheaper.”

As in the earlier work, this new system relies on a combination of approaches: namely, interference patterns between two light sources and a photochromic material that changes color when illuminated by a beam of light. But, Andrew says, a new step is the addition of a material called a photoresist, used to produce a pattern on a chip via a chemical change following exposure to light. The pattern transferred to the chip can then be etched away with a chemical called a developer, leaving a mask that can in turn control where light passes through that layer.

While traditional photolithography is limited to producing chip features larger than the wavelength of the light used, the method devised by Andrew and her colleagues has now been shown to produce features one-eighth that size. Others have achieved similar sizes before, Andrew says, but only with equipment whose complexity is incompatible with quick, inexpensive manufacturing processes.

The new system uses “a materials approach, combined with sophisticated optics, to get large-scale patterning,” she says. And the technique should make it possible to reduce the size of the lines even further, she says.

The key to beating the limits usually imposed by the wavelength of light and the size of the optical system is an effect called stimulated emission depletion imaging, or STED, which uses fluorescent materials that emit light when illuminated by a laser beam. If the power of the laser falls below a certain level, the fluorescence stops, leaving a dark patch. It turns out that by carefully controlling the laser’s power, it’s possible to leave a dark patch much smaller than the wavelength of the laser light itself. By using the dark areas as a mask, and sweeping the beam across the chip surface to create a pattern, these smaller sizes can be “locked in” to the surface.

That process has previously been used to improve the resolution of optical microscopes, but researchers had thought it inapplicable to photolithographic chip making. The innovation by this MIT and Utah team was to combine STED with the earlier absorbance-modulation technique, replacing the fluorescent materials with a special polymer whose molecules change shape in response to specific wavelengths of light.

In addition to enabling the manufacture of chips with finer features, the technique could also be used in other advanced technologies, such as the production of photonic devices, which use patterns to control the flow of light rather than the flow of electricity. “It can be used for any process that uses optical lithography,” Andrew says.

In addition to Andrew, the paper’s authors include Rajesh Menon, formerly a research engineer at MIT and now an assistant professor of electrical engineering and computer science at Utah, and Utah postdoc Nicole Brimhall and graduate student Rajakumar Varma Manthena. The work was supported in part by grants from the U.S. Defense Advanced Research Projects Agency and the National Science Foundation.

Written by: David L. Chandler, MIT News Office

Kimberly Allen | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht Move over, lasers: Scientists can now create holograms from neutrons, too
21.10.2016 | National Institute of Standards and Technology (NIST)

nachricht Finding the lightest superdeformed triaxial atomic nucleus
20.10.2016 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>