Pioneer of nano-printing lithography solutions
Stensborg has been a pioneer for 20 years in nanoimprint lithography solutions for research institutes and industry. Jose Pozo, CTO of EPIC, interviewed CEO Jan Stensborg about the development of this private Danish company, its technology and the future of nanoprinting in important application areas.
Originally trained as a toolmaker, in 1982 Jan joined the Royal Danish Navy, where he specialized in scuba diving, explosives and search and rescue of fishing vessels in the North Atlantic, especially around Greenland.
During this time he became fascinated with holograms and the potential of lasers to provide 3D visualization for scuba diving, especially for oil rigs. Thus, when he left the navy in 1987, he converted to the Holographic Laboratory, an entity derived from the Technical University of Denmark. Over the next 10 years, he worked with various research groups on holography and interferometry, a technique that uses the interference of light waves to measure distances with great precision. In the early 90s Jan started working with companies like Bang Olufsen and Lego and other Danish companies who were starting to see the benefits of interferometry for testing product integrity, Heads Up Displays (HUDs) and counterfeit applications.
They have also worked with various forms of embossing and injection molding and have teamed up with researchers and companies working on nano-printing producing CDs and DVDs. Then, in the mid-90s, following IBM’s example, they started experimenting with polydimethylsiloxane (PDMS) to make nano-imprints on opaque substrates.
The creation of Stensborg A / S
With the aim of using the experience and expertise that Jan and his team have accumulated over the past 10 years, Stensborg A / S was established in 1998 to help companies implement nanolithography by printing and maximize its use.
Technology: By 1999 it had become evident that the then current techniques and materials for nanoprinting had a number of limitations. First, infrared heating and hot embossing had several drawbacks and there was a need for UV curable materials. Second, while PDMS was good for what IBM invented it to do, the material was too soft and the resins diffused into the polymer, making it unsuitable for printing.
At the same time, governments and the banking industry were increasingly demanding high-volume security and anti-counterfeiting printing solutions, which required a technique of volume nano-printing on opaque substrates using UV curable materials.
As a solution, Stensborg came up with a revolutionary printing technique – Holoprint® which allows users to print high-resolution three-dimensional (3D) surface relief nanostructures directly onto their pre- or post-printed web material, without the need to use prefabricated sheets.
Over the next 15 years, Stensborg developed two innovative methods of nanoimprint lithography (NIL) based on their patented technology. The first was the Roll-to-Roll (R2R) method used for volume manufacturing on flexible materials, including paper and polymers. For this method, which was first introduced in 2010 in Germany, Stensborg developed its own unique and patented pinch-molding process designed for nanoprinting on transparent and opaque materials. The advantages of this approach are that it avoids costly and unwanted tape coatings, enables in-line partial register nanoimprinting, reduces costs and the manufacturing process through partial provision of an active nanoimprint area, and a a positive environmental impact due to the speed of production and low energy consumption.
The second method was Roll-to-Plate, which is a printing process consisting of a roller mechanism and a rigid surface plate. This technique, first introduced in 2016 in Austria, is better suited for the production of inflexible substrates, e.g. glass and quartz and is the preferred method for prototyping optical masters as it allows the production of smaller quantities, thus reducing time consumption while minimizing waste. This is an ideal method for experimenting and testing new nanoimprint topologies before mass production. Its main advantages are that it prints a micro- or nanostructure in a thin nip line, and automatically compensates for substrate irregularities, and enables a fast sample making method as well as a tool to set parameters. for the future Roll-to-Plate ramp up
Thanks to Stensborg’s pioneering work, solving the problems of volume nanoimprint lithography is considerably easier today than it was 20 years ago. In fact, it is no exaggeration to say that the current nanoimprint lithography industry is indebted to Stensborg’s advanced nanoimprint lithography solutions developed over the past two decades.
Some products: Stensborg has grown to become a full-fledged facility with clean room facilities, chemical development and production of optical components. The company currently offers 4 types of products: 1) Released in 2019, the Holoprinter Uni A6 DT is a portable and affordable solution to provide research institutes with an easy-to-use product for small-scale nanoprinting, roll-to manufacturing -plate lithography work.
This desktop device is ideal for prototyping, testing and characterizing materials and processes for applications such as diffractive optics, holographic optics, hydrophobic topologies, and lab-on-a-chip devices; 2) a range of consumables for nanoimprint lithography, such as master model UV resins and light curing resins; 3) volume production using R2R and R2P fabrication, for example, for diffractive optical elements, optical waveguides and holographic optical elements; 4) Tailor-made services to meet the specific needs of their customers, from light-curing resin to equipment modifications and bespoke machinery and chemicals.
Enable future volume production
On the product side, Jan is optimistic that their Holoprinter Uni A6 DT will be good for future business, not only in terms of revenue, but also because of its potential to enable future volume production. . University researchers and private research labs have a desktop device they can use to quickly test and develop new nanoimprint topologies. As Jan points out, young students can come up with very smart ideas for new applications, for example, in energy, medicine and communications, and new detection methods that cannot be used with traditional technologies. Stensborg can help you where there is business potential to move towards high volume production.
For volume production, there are currently 5 main growth areas.
Micro-optics: Since 2018, large companies have seen increasing interest in micro-optics and luckily, major new developments will help to serve these companies through: 1) the provision of customized optical masters from companies like SPIO Systems ApS and NIL Technology ApS ; and 2) the latest developments in the industry to make major topologies.
Medical: The second area of growth is the medical sector, particularly for microfluidics and topology enhancement applications, for example, for DNA analysis and point-of-care diagnostics.
Solar energy: There is a growing interest in Europe for solar power generation, and in this regard, Stensborg has already provided nano-printing solutions to improve the functionality of flexible solar cells as well as solar concentrators. Another area of growth in the solar market is coloring rigid and flexible solar cells to make them more aesthetic for planners and architects. The challenge is how to add color without degrading efficiency, which Stensborg is currently tackling by changing topologies.
Communication: Another growing market is that of optical communications resulting from the greater use of polymers and optics, for example the manufacture of part of a polymer lens and part of glass. The advantages of polymers over glass are that, although they have the same optical quality, they are faster to process, therefore more competitive in terms of price and can open up to new applications in the market.
Free-form micro-optics: Finally, in recent years there has been an explosion in free-form micro-optics. These are micro-optical components designed without symmetry constraints, which gives them improved performance compared to traditional micro-optical imaging systems. Applications include augmented reality (AR) displays, commercial and consumer lighting, and solar panels. Ultimately Jan sees a time when glasses are available that allow the wearer to “see” and adjust both visible and non-visible light.
If you started over, what would you do differently?
” I have no regrets. Looking back, it’s always possible to think that something could have been planned. But, that said, I think I would trust my gut more and be more proactive when I see the potential of a particular technology. For example, the potential of diffractive optics for medical applications was evident several years ago, but I, like many others, did nothing because it was too heavy to convince the industry.
What are your words of wisdom for the next generation of entrepreneurs?
“First of all, find something that fascinates you and study the subject as much as you can. Second, learn as much as possible from others and trust your gut when you go above and beyond. Third, don’t be afraid to share your ideas; getting feedback is important and if someone copies you take it as a compliment.
Written by Jose Pozo, CTO at EPIC (European Consortium of the Photonics Industry).