Researchers at the University of Maryland College of Chemical and Life Sciences have developed a new technique which will improve nanofabrication, and in the same time it will make it cheaper. The advances in nanotechnology are important in manufacturing computer microchips and other tiny devices, but they are more important to create smaller structures.
In order to design structures smaller than human hair, you will need to use a technique called photolithography which requires difficult-to-use and expensive ultraviolet light. The team of researchers at the University of Maryland College of Chemical and Life Sciences led by John Fourkas, Professor of Chemistry and Biochemistry, have developed a new photolithography technique which doesn’t require ultraviolet light. The team called it RAPID, short for Resolution Augmentation through Photo-Induced Deactivation.
The well-known process of photolithography is based on light to deposit and remove materials, and create tiny patterns on surfaces. The researchers say that there is a strong link between the size created and the wavelength used so until now nanofabrication required ultraviolet light to create nanostructures.
“The RAPID lithography technique we have developed enables us to create patterns twenty times smaller than the wavelength of light employed which means that it streamlines the nanofabrication process. We expect RAPID to find many applications in areas such as electronics, optics, and biomedical devices,” said Fourkas.
Fourkas and this research group used two laser light sources of the same color – the first was used to harden the material, while the latter was used to prevent the material from hardening. The difference between the two was that the first produced only short bursts of light, while the latter was kept on perpetually. Also, the second laser light went through a custom optic which was designed to allow the sculpting of the hardened materials.
“If you have gotten a filling at the dentist in recent year, 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. The fact that one laser is on constantly in RAPID makes this technique particularly easy to implement, because there is no need to control the timing between two different pulsed lasers,” said Fourkas.
The study is only at the beginning but Fourkas says that his team already made some important advances, and that now they are looking to improve RAPID as they want to create structures half the size of the one they created so far.