DoMicro finished its Rocket Feasibility Study successfully. ‘Our electro-hydrodynamic nanowire printing (ENP) technology has proven feasible, versatile and promising,’ says managing director Marcel Grooten.

Together with its Rocket-partners, DoMicro succeeded in combining ENP enabling technology with a robust inkjet platform (PiXRO LP50), as used already in academic R&D, and marketed by Meyer Burger.

Marcel Grooten generously expresses gratitude to Rocket co-partner: microTEC, based in Duisburg. ‘Together we completed the exact design parameters and system architecture requirements for this challenging integration of technologies,’ he says.

Grooten: ‘We met at the Rocket launching event in Kleve, clearly understanding each other’s technology needs in this project. And, more in general, we both knew exactly what product and process development, in this innovative field, is all about. We are happy to have met such a well-informed partner in Germany. Besides, Duisburg is not far from Eindhoven, where we are based. The collaboration was familiar right from the start.

Proof of principle

From this inspiring contact, the partners formulated a Rocket Feasibility Study: to realize and test a functional proof of principle research nanowire printer, the DM50-ENP. Other application areas for ENP, such as: microfluids lab-on-chip, microsystem structures, displays and semiconductors, were also addressed.

In the well-equipped micro device lab of DoMicro, Grooten shows the integration setup that resulted from the Feasibility Study. One can see how the nozzle tip and Taylor cone (containing the jetted polymer solution) is integrated with the printer platform. While the platform moves, small solidified nanowires, of only some micrometers thick, are printed onto the substrate.

Italy

Some years ago Grooten came across the electospinning technology while visiting a scientific conference in Italy. ‘Immediately I realized its potential,’ he says. ‘To really contribute in applications in semiconductor industries, feature sizes of 5-10 micron are obligatory.

In scientific research, feature sizes of some hundreds of nanometers are already realizable by using electrospinning technology. That is well below 1 micron, as it is beyond human perception: structures smaller than 3 micron are below the visibility frontiers of human sight!

Silver nanoparticles

By direct write mode and under high voltage, nanowires can be made from multiple sorts of polymers, and be applied and positioned on substrates in a highly controlled manner. Applying silver nanoparticles in these polymer solution materials – as processed successfully already by Dow Chemical Company – transparent structures, patterns and substrates are within reach nowadays. ‘This means these tiny nanowires can be made conductive,’ Grooten says. ‘So, actuator devices are conceivable, processed by these invisible silver-polymer threads.’

Paradigm shift

Some specialized companies do already use electrospinning, mostly concentrating on bulk properties such as in non-woven textile applications. ‘Our target, however, is aiming in the reverse direction, towards functional applications in ultra small-sized electronic devices,’ thus Grooten.

According to Grooten OLED and organic photovoltaic (OPV) electrodes may become feasible using nanoprint technology. In his view, paradigm shifts and society advantages lay ahead. One day transparent conductive films will replace scarce earth materials, now widely used in IndiumTinOxide (ITO) touch screens. Also new generations of transistors on flexible substrates and transparent heaters, integrated on wafers, are feasible. Grooten sees ahead unthought-of application fields in: touch screens, batteries, memory and bio chips, Mems technology and microfilters.

Other Rocket partners

Grooten points out the great contribution in this Rocket project coming from another partner: PPE Holland (Production and Process Engineering). ‘Their expertise was crucial, in designing and building the test equipment.

Further, the system integration for the printer is taken on by yet another Rocket partner, Tec-V. They covered the electronic and software architecture concerning the steering and feedback modules between the nanoprinter modules and the platform, using specialized cameras.

Grooten: ‘We not only focused on the technology aspects. Our collaboration with TechToBizz, in Waalre, has further strengthened our belief that both in semiconductor industry (including 3D electronics, systems and packages) and in display technologies (including touchscreens with nanowires as an alternative for ITO), business opportunities are abundantly available. This intuition is confirmed once and again when talking to market researchers and product developers all over the world.

Cliff-hanger

Although unmistakable progress has been made within the half year Rocket Feasibility Study, Grooten at present is facing a cliff-hanger situation. ‘The near-field aspects of nanowire printing are very demanding, involving a new and, to a certain extent, unpredictable working field for us,’ he says.

For nanofiber production the polymer suspensions must be charged, in order to ‘draw’ the wires onto the substrate, in a highly controlled manner. ‘It is fair to say we are in need of another development stage, requiring some tons of investment,’ Grooten says. ‘We need these investments in order to come to real module system integration, application-integrated software development tools, and further developing sintering techniques, to robustly and verifiably affix the nanowires to the wafer substrates.

If these next steps can be taken successfully, Grooten is very optimistic regarding future applications. ‘By then we will be more than ready for a following Rocket-like innovation project. I am sure we will be able to fulfil the required market conditions and we will be able to launch one or two products with new partners. I suppose we can then provide our first commercially successful equipment nanowire printing tools, to international academics or research institutes, as launching customers.

Dieser Artikel wurde verfasst von Egbert van Hattem, Coördinator Science Shop Twente