With the highly innovative Laser-Direct-Write process for 3D nanostructuring from the dynamic new company, Nanoscribe GmbH, almost any kind of three-dimensional structure can be produced from various photo-sensitive materials. The optics company, Carl Zeiss AG based in Oberkochen in Germany made a very positive move in acquiring just under 40 percent in the Nanoscribe start-up. Nanoscribe is based in Karlsruhe, Germany.

The new Laser-Direct-Write process for 3D nanostructuring was originally developed for nanophotonics. This still relatively young 3D laser lithography discipline is used in micro- and nanophotonics, life sciences, biotechnology and microfluidics. This process is currently being used, for example, in the production of three-dimensional photonic crystals, or even for cell growth studies in specially tailor-made spatial environments in biology.

Nanoscribe develops and produces compact rapid-prototyping laser lithography systems for producing three-dimensional micro and nanostructures in photoresists (picture 1). The company also offers the design and production of structures in various photosensitive materials that are specially customer-oriented, e.g. chalcogenide glasses, SU-8 or Ormocers as a service.

3D laser lithography uses multi-photon absorption for the local high resolution illumination of photosensitive materials. The illuminated areas have a different chemical solubility to their surroundings, so that complex three-dimensional structures can be generated in the sub-micrometer range. The process uses ultra-short laser pulses, which have single-photon energy below the absorption threshold of the photosensitive medium to be illuminated. The material is therefore transparent for the laser light. If this laser beam is heavily focused, however, then multi-photon absorption processes increase in the focal volume. The material is chemically and/or physically modified at this point, and therefore selectively chemical soluble vis-à-vis the surrounding material.

As the photosensitive materials only first react after a specific illumination level is reached, the process permits the production of structure values that are significantly below the diffraction limit of the optics used. Line widths of several micrometers down to 150 nm are reached with 5 nm reproducibility. The processing volume depends on the optics and the scanner configuration. 300 x 300 x 80 µm3 are standard. Joining several processing volumes together allows surfaces of up to 10 x 13 cm2 to be structured. Writing speeds up to 2 mm/s are reached here.

The laser lithographs (picture 2) are set up as compact and encapsulated systems, which can also be used in a clean room environment with numerous workstations. The lasers used must be very stable in their performance. Fiber lasers provide the best conditions for this. With the acquisition of just under 40 percent of the Nanoscribe GmbH start-up based in Karlsruhe, Germany, Carl Zeiss has also secured the benefits of a future-oriented technology.

The two companies have been cooperating since 2007, and Nanoscribe delivered its first system at the end of June 2008. Professor Martin Wegener, one of the founders and scientific consultants of the start-up, received the Carl Zeiss Research Award in 2006.  In addition to the investment, Carl Zeiss also supports the young company with its wealth of know-how and experience. Nanoscribe has the potential to open up new application fields in optical technologies. The partnership with Carl Zeiss is a milestone on this path to the future.
Bucky Ball – A symbol of the three-dimensionality of the innovative laser lithograph process, now commercially available for the first time.
Photo: Nanoscribe