Stensborg’s Rolling Nanoimprint Lithography (RNIL) process is a sophisticated technique used for high-resolution nanofabrication. Its high throughput, reliability, and cost-effectiveness benefit both small-scale researchers and mass manufacturers, playing a pivotal role across applications in flexible electronics, energy, photonics, and biotechnology.
Let’s dive into the technical innovations behind our unique rolling Optical Engine, carefully designed for nanoimprinted structures professionals.
Image credit: Stensborg A/S
Roll-to-roll (R2R) and Roll-to-Plate (R2P) Nanoimprint Lithography (NIL) are high-volume, low-cost replication methods used for manufacturing electronics, medical devices, and optical components. Both of these processes involve contacting a liquid resin with a patterned tool and curing it using UV light.
A well-designed optical engine is crucial for high-yield production. Stensborg’s patented Nanoimprint Optical Engine was developed throughout 20+ years of imprinting expertise and can be found in all of our machinery, from prototyping to mass production solutions. This advanced feature ensures precise control over imprinting conditions, from pressure to rolling speed and UV intensity, benefiting productions across industries.
Our high-performing rolling Nanoimprint Lithography (RNIL) method has boosted worldwide productions: in academic laboratories empowered by our compact Desktop R2P NanoImprinter or in large-scale facilities with our custom-built equipment.
Benefits of Rolling Nanoimprint Lithography (RNIL)
Figure 1:Illustration of the RNIL process with the optical engine (not to scale).
In RNIL manufacturing, the final devices are created in a, continuous process. As illustrated in Figure 1, the process operates a patterned template against a substrate coated with a UV-curable resin, either on a flexible web (in Roll-to-Roll) or on a rigid individual plate (Roll-to-Plate). Once the template contacts with the resin, UV light is used to cure the resin, solidifying the imprinted patterns.
The Rolling NIL process stands out for its ability to produce intricate nanoscale features with high fidelity and consistency, driving innovation across various advanced technology sectors.
Specifically in high-volume manufacturing, throughput and replication quality are essential for achieving optimal results. Stensborg’s optical engine controls UV-light intensity, operational force, imprinting pressure, and speed, warranting the users’ full control over the development process. By providing technically advanced customisation, researchers and manufacturers can optimise, monitor and ensure error-free imprintings, obtaining high product consistency while remaining energy efficient.
Key advantages of the Rolling NIL process include:
Mastering the details: intricacies of Stensbog’s Optical Engine
Stensborg’s Optical Engine provides precise UV-light intensity in the nip and ensures optimal imprinting force suitable for high-speed rolling nanoimprinting processes.
Its modular and scalable design allows for adjustments from small to large widths, equipping developers with a smart flexible solution that caters to their needs, from experimentation to mass production.
The main technological feature of the nip was designed with innovators in mind, ideally suited for high-speed, continuous RNIL developments. Through the nip, the pressure is applied along a narrow line, as shown in Figure 2, rather than in a larger two-dimensional area used in conventional Plate-to-Plate (P2P) nanoimprinting, leading to better performance and reproducibility.
Figure 2: Pressure and illumination along a line in the nip design.
Shedding light on the design and materials
In high-speed RNIL, UV-light curing is the preferred replication method for its rapid and consistent processing capabilities. The energy applied to the resin from the UV light source depends on the intensity of the light (I) and the time (Δt) the resin is exposed to.
E = I*Δt
Our carefully crafted design ensures the resin is cured while the template is in contact, reducing shrinkage effects. To achieve this processing feature, we rely on high UV-light intensity focused in a nip. Stensborg’s Optical Engine uses this high-intensity UV LED, optimised for efficiency and low cost, reaching a lifespan of over 10,000 hours, which outperforms the legacy of gas-discharge lamps.
The usable wavelengths for most UV-curing resins fall within the UVA range of 315 nm to 400 nm. Stensborg specialists rely on LEDs with a centre wavelength of 395 nm, which are the most efficient and cost-effective, and develop in-house compatible resins that are optimised for 395 nm as well.
Figure 3: Transmission of PVC, PET and PC in the range from 200 to 500 nm.
However, absorptivity is as important as light intensity in crafting reliable nanoscale functional surfaces. Polymers typically absorb UV light at wavelengths below 300-400 nm, as shown for materials such as PET, PVC, and PC. Using longer wavelengths, such as 395 nm, we can expand the range of usable materials for substrates, templates, and other optical elements, spreading the range of applications of our NIL solutions.
Figure 4 showcases our optical engine technology where a row of UV-LEDs is used to form the line illumination featured in all our nanoimprinting equipment.
Figure 4: Light source module with line of UV-LEDs.
The optics behind the technology
Stensborg’s Optical Engine contains multiple lenses to focus UV light into a high-intensity beam, optimising light coupling and minimising absorption. The compact design enables the engine to fit seamlessly into the imprint roller featured in our rolling NIL machines while ensuring highly efficient results.
All lenses have absorption and scattering effects, which affect replication accuracy. To mitigate this issue, Stensborg relies on special material types for both our lenses and the imprint roller featured in our NIL machines.
Our optics technology effectively couples UV light, addressing both transverse and parallel dimensions to the illumination line. Parallel to the line, the optics act as a flat window with no focusing effect. Transversely, the optics collect light from the LED and focus it on a line typically less than a few mm wide. This dual-action approach ensures exceptional performance and precision in UV light curing.
Try it yourself
Figure 6: Stensborg Desktop R2R NanoImprinter.
The Stensborg’s Desktop R2R NanoImprinter (Figure 6) is ideal for developing UV-NIL prototype processes, allowing easy adjustments to pressure and light dose.
Whether you are looking for fast prototyping tooling or taking cost-effective steps toward mass production, our Roll-to-Plate unit is your optimal solution.
Featuring our advanced optical engine, the desktop’s performance is seamless across both settings, equipping academic cleanrooms, research laboratories, and industrial facilities with a versatile and high-precision tool.
Work with us and boost your productivity!
