VTT and SUSS MicroTec S.A.S. have developed the most versatile nano imprinting stepper on the market. The stepper and new methods form enabling technology for fast, low-cost production of flexible solar cells and nano-scale bio analysis platforms (Lab on a Chip). The stepper was developed within the framework of the Emerging Nanopatterning Methods project. VTT is already using a prototype of the NPS300 stepper at its laboratory in Micronova in Espoo Finland.
Based on Step and Stamp Imprint Lithography (SSIL), the stepper uses a patterned chip as a stamp; the stamp pattern is transferred to a polymer layer by imprinting. Large-scale replication of patterns is done by means of Step and Stamp imprinting. The stepper enables multi-layer imprinting with high-accuracy alignment. Both thermoplastic and UV cured material may be used. The patterned polymer layer can be used as an engraving mask when printing patterns on silicon or quartz. The method enables quick, low-cost replication of sub-100 nm geometries on a large area.
Traditionally, nano-scale geometries have been printed using e-beam lithography. This method has one weakness: it is slow. While other microelectronics equipment and methods may be used to produce sub-100 nm line widths, such equipment is extremely highly priced. Furthermore, traditional methods are not easily adaptable for printing on new functional materials or using 3D geometries.
E-beam lithography will continue to be used for the tiniest stamp patters also in the future. However, Step and Stamp patterning can be used for large area processes. It can also be applied to produce stamps for roll-to-roll nanopatterning.
Suitable for new materials and 3D geometries
The new stepper is suitable for nanopatterning of optical and electronic materials and biomaterials as well as 3-dimensional replication. VTT has even been able to produce sub-10 nm geometries. Thanks to its high-accuracy alignment, nanopatterning can be performed on the same platform with other patterning methods. The method is cost-efficient and fast, which makes it ideal for mass-scale production.
Nanopatterning is an enabling technology, with applications such as biotechnology, photonics, nano- and polymer electronics, hard drives, sensors, etc. Micronova's cleanroom equipment and process can cover the entire process chain from stamp manufacture to characterisation.
Emerging Nanopatterning Methods - VTT's biggest EU project
Coordinated by VTT, the Emerging Nanopatterning Methods (NaPa) project reinforces nanotechnology research in Europe. Launched in 2004 with a budget of EUR 31 million, the project is the largest EU project coordinated by VTT, as well as one of the EU's largest nanotechnology projects. The project aims at standardising the nano- imprinting processes and establishing a process library. In order to promote the feasibility of solutions developed the within the project, special focus is paid to cost-efficiency. The environmental friendliness of the process is another key aspect. One of the most significant project outcomes is the NPS300 nano imprinting stepper.
The project has also been concerned with developing roll-to-roll methods for the production of nano-geometries. A printer designed by VTT combines the new nanopatterning method with gravure printing and flexo techniques in one process run. This printer is already used by VTT as well.