New Laser Technique Advances Nanofabrication Process

April 9, 2009
Schematic depictions of RAPID lithography, the technique developed by John Fourkas and colleagues which enables the creation of features 2500 times smaller than the width of a human hair.

( -- The ability to create tiny patterns is essential to the fabrication of computer chips and many other current and potential applications of nanotechnology. Yet, creating ever smaller features, through a widely-used process called photolithography, has required the use of ultraviolet light, which is difficult and expensive to work with.

John Fourkas, Professor of Chemistry and Biochemistry in the University of Maryland College of Chemical and Life Sciences, and his research group have developed a new, table-top technique called RAPID (Resolution Augmentation through Photo-Induced Deactivation) lithography that makes it possible to create small features without the use of . This research is to be published in Science magazine and released on on April 9, 2009.

Photolithography uses light to deposit or remove material and create patterns on a surface. There is usually a direct relationship between the wavelength of light used and the feature size created. Therefore, has depended on short wavelength ultraviolet light to generate ever smaller features.

"The RAPID lithography technique we have developed enables us to create patterns twenty times smaller than the wavelength of light employed,"explains Dr. Fourkas, "which means that it streamlines the nanofabrication process. We expect RAPID to find many applications in areas such as electronics, optics, and biomedical devices."

"If you have gotten a filling at the dentist in recent years,"says Fourkas, "you have seen that a viscous liquid is squirted into the cavity and a blue light is then used to harden it. A similar process of hardening using light is the first element of RAPID. Now imagine that your dentist could use a second light source to sculpt the filling by preventing it from hardening in certain places. We have developed a way of using a second light source to perform this sculpting, and it allows us to create features that are 2500 times smaller than the width of a human hair."

Both of the laser light sources used by Fourkas and his team were of the same color, the only difference being that the laser used to harden the material produced short bursts of light while the laser used to prevent hardening was on constantly. The second laser beam also passed through a special optic that allowed for sculpting of the hardened features in the desired shape.

"The fact that one laser is on constantly in RAPID makes this technique particularly easy to implement,"says Fourkas, "because there is no need to control the timing between two different pulsed lasers."

Fourkas and his team are currently working on improvements to RAPID lithography that they believe will make it possible to create features that are half of the size of the ones they have demonstrated to date.

More information: Achieving lambda/20 Resolution by One-Color Initiation and Deactivation of Polymerization was written by Linjie Li, Rafael R. Gattass, Erez Gershgorem, Hana Hwang and John T. Fourkas. (published in Science Express)

Provided by University of Maryland (news : web)

Explore further: Scientists coax gold particles to emit light strong enough to view single nanoparticles

Related Stories

UM Team Devises Way to Use Metal in Micromachines

February 9, 2006

In the world of microtechnology, entire "machines," so tiny the naked eye can't see them, can be manufactured to create things like sensors that deploy car air bags. But conventional micromachine fabrication technologies ...

Recommended for you

Physicists develop new technique to fathom 'smart' materials

November 26, 2015

Physicists from the FOM Foundation and Leiden University have found a way to better understand the properties of manmade 'smart' materials. Their method reveals how stacked layers in such a material work together to bring ...

Mathematicians identify limits to heat flow at the nanoscale

November 24, 2015

How much heat can two bodies exchange without touching? For over a century, scientists have been able to answer this question for virtually any pair of objects in the macroscopic world, from the rate at which a campfire can ...

New sensor sends electronic signal when estrogen is detected

November 24, 2015

Estrogen is a tiny molecule, but it can have big effects on humans and other animals. Estrogen is one of the main hormones that regulates the female reproductive system - it can be monitored to track human fertility and is ...


Adjust slider to filter visible comments by rank

Display comments: newest first

5 / 5 (2) Apr 09, 2009
The intensity periodicity is still diffraction-limited.
5 / 5 (2) Apr 09, 2009
It's interesting but there are already lots of tricks that will do with the conventional light source, e.g., contrast enhancement layer, reflow, trimming, etc.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.