Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Taking Nanolithography Beyond Semiconductors

18.12.2006
A new process for chemical patterning combines molecular self-assembly with traditional lithography to create multifunctional surfaces in precise patterns at the molecular level.

The process allows scientists to create surfaces with varied chemical functionalities and promises to extend lithography to applications beyond traditional semiconductors. The new technique, which could have a number of practical chemical and biochemical applications, will be described in the 22 December 2006 issue of the journal Advanced Materials by a team led by Paul S. Weiss, distinguished professor of chemistry and physics at Penn State and Mark Horn, associate professor of engineering science and mechanics at Penn State.

The technique uses self-assembled monolayers (SAM) -- chemical films that are one molecule thick -- to build a layer on a surface, followed by the addition of a photolithographic resist that protects the covered parts of the film during subsequent processing. The resist acts as a shield during processing, allowing the cleaning and then self-assembly of different chemical functions on the unprotected parts of the surface. "Other chemical patterning processes on surfaces suffer from cross-reactions and dissolution at their boundaries," says Weiss. "In our process, the resist provides a barrier and prevents interactions between the molecules already on the surface and the chemistry being done elsewhere. The resist is placed on top of the pattern by standard photolithographic techniques. After the resist is placed, molecules are removed from the exposed areas of the surface. Subsequent placement of a different SAM on the exposed surface creates a pattern of different films, with different functionalities.

Because the resist protects everything it covers, the layer under it does not have to be a single functionality. As a result, a series of pattern/protect/remove/repattern cycles can be applied, allowing complex patterns of functional monolayers on the surface of the substrate. "It allows us to work stepwise across a surface, building complex patterns," says Weiss. "We have demonstrated patterns at the micrometer scale and have the potential to go down to nanometer-scale patterns." While the two processes used by the team -- molecular self-assembly and photolithography -- are individually well-developed, the team's innovation is the successful combination of the techniques to build well-defined surfaces.

Chemical functionalities are distributed across the surface in high-quality layers as a result of the self-assembly process and in high-resolution patterns due to the use of the specialized resists. Different chemical functionalities can be used to detect or to separate a variety of species from a mixture. "The product of the process can be used to create a multiplexed, patterned, capture surface," says Weiss. "We could expose the entire surface to one mixture and capture different parts of the mixture in each region."

The work was a collaborative effort between the Weiss group, specializing in surface chemistry, and the Horn group, specializing in nanolithography. In addition to Weiss and Horn, the Penn State research team included graduate students Mary E. Anderson (now graduated), Charan Srinivasan, and J. Nathan Hohman, as well as undergraduate researcher Erin Carter. The work was performed as a part of both the National Science Foundation supported Center for Nanoscale Science and Penn State's node of the National Nanofabrication Infrastructure Network.

Barbara K. Kennedy | EurekAlert!
Further information:
http://www.psu.edu

More articles from Materials Sciences:

nachricht Watching atoms move in hybrid perovskite crystals reveals clues to improving solar cells
22.11.2017 | University of California - San Diego

nachricht Fine felted nanotubes: CAU research team develops new composite material made of carbon nanotubes
22.11.2017 | Christian-Albrechts-Universität zu Kiel

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Underwater acoustic localization of marine mammals and vehicles

23.11.2017 | Information Technology

Enhancing the quantum sensing capabilities of diamond

23.11.2017 | Physics and Astronomy

Meadows beat out shrubs when it comes to storing carbon

23.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>