For the production of microsystems various solutions for high-volume and low-cost production already exist. The purpose of Light-Rolls is not to replace those manufacturing solutions, but to apply basic research results for the development of new manufacturing processes for new science based products in order to enable their cost efficient production and thus to generate potentially disruptive products and production systems. This state-of-the-art describes existing manufacturing solutions, and explains the progress how Light-Rolls enables future production.
The new RMPD®-Rotation module translates the batch oriented RMPD®-mask technology to a seamless Roll-to-Roll production method. Main advantages will be higher throughput than the mask based process, cost efficient manufacture of large area structures, and also an easier, seamless integration into production processes.
Either large area polymer components can be printed in one stream (like light emitting wall paper) or many small parts will be generated in a seamless, parallel process (e.g. CD-size microfluidic systems, credit card sized lab-on-chip systems, finger nail size micro-titre plate inserts). Shark skin-type surfaces are also possible on large scale.
The Rotation process also allows multi-material processing, i.e., different polymers can be integrated in one part. This enables the integration of 2 or more materials in one part, e.g. with different refractive indices for the realization of waveguides. A second excellent example is the integration of intrinsic hydrophilic and hydrophobic materials in one part for long term stable micro-fluidic chips.
The Rotation system will combine the art in printing with very fast-curing monomers, and depositing very small patterns with a layer-to-layer production, in a Roll-to-Roll type process. This has never been done before.
Self-Assembly of small dies based on capillary and adhesive forces- beyond State-of-the-art in roll-to-roll approach
The Light-Rolls approach will follow a different strategy. Based on the IPA research, the assembly of very small dies will be developed and proven for a first industrial application of IPA and NSMZ in Light-Rolls. The state of the art is to take the dies from the wafer by the sequential pick-and-place process. In Light-Rolls the new approach is to bring the dies into a feeder unit and place many dies in parallel onto the seamless polymer interim substrate using the self-assembly effect for a precise and fast assembling. The lift-off approach is also new, and offers a large degree of flexibility, because large dies can be delivered from a second source onto this interim substrate as well. The integration of chip self assembly methods into Roll-to-Roll production has also not been implemented in Europe before.
Electronic Printing beyond State-of-the-art in roll-to-roll approach
In order to use the inkjet technology in electronic integration and miniaturisation, further development is required. Materials are still being developed and new materials are continually released. In particular, the optimisation of the flow of ink can impact the conductivity of final material. Also, the performance and cost are not compatible with current technologies. The high potential of inkjet must be seen as the enabling integration technology and not only as a replacement technique for current applications. Inkjet will enable crossover and multilayer structuring, which will give much more freedom for product design. Light-Rolls will primarily use the ink jet and Xerographic printing technologies in order to create small and precise features. Especially the knowledge from the xerographic technology for tempering and fixing of the Inkjet layer for the required post processing promises high potential. At first the existing print head will be adapted for the requirement of nanoparticulate dispersions. Secondary, in order to establish an in-line production process for nanoparticulate coatings an interdisciplinary approach is pursued by IPA and Xaar. For a successful accomplishment of the project expertise in the fields of nanoparticulate dispersions, coating and printing technology as well as Xerographic technology will be contributed. The main challenge is to generate temperaturetime characteristics and decrease temperatures in the coating down to, e.g., 120°C, not to damage the substrate or microstructures and not to loose accuracy in the Roll-to-Roll configuration. This is possible and will clearly mean a progress beyond the state of the art.
Roll-to-roll production systems beyond State-of-the-art
For years roll-to-roll equipments are well known, in packaging & assembly at macro-scale as well as in printing industry. These Industries are nowadays mature, and almost totally cost-driven, so they have become a synonym for highest degree of automation and high speed production. Flexible electronics is an emerging market with a massive potential and a huge range of possible applications, from displays and lighting to smart packaging. While the technology is proven, there is a growing need for new manufacturing methods and technologies to support volume production. This is where Light-Rolls will offer new unique production solutions. Light-Rolls will apply new polymer based production methods, new chip assembly methods, optimized interconnection technologies, all that in a Roll-to-Roll approach. Polymer based components are not limited to thin films, but thicker as well (e.g., a fluidic chip with integrated electrodes).
Many LED based lighting applications are on the market. A “simple” one is white background lighting of, e.g. displays (s. two pictures below, Source: DLED), but also “mood lighting”, shaped or curved etc.
There are still some significant drawbacks associated with the application of organic materials to optoelectronic devices (unsatisfactory chemical stability of the organic materials, limits on lifetime especially in harsh environmental conditions).
Light Rolls will not replace the LCD display technology which much of the OLED activity is directed at. The "display" products which Design LED are currently working on would be more properly termed "human machine interface".
Neither of the standard packaging approaches (like Wire bonding or Flip-Chip) have a manufacturing process compatible with the high volume, high throughput and most importantly, the large area required for the product market requirement. The sparse die integration over a large area is very different from standard microelectronic integration trend where making product smaller is the main goal.
The Light-Rolls equipment platform will process a thin, transparent foil as a substrate layer in a roll-to-roll process. The platform is suitable to integrate microfabrication processes. The aim of the equipment concept to be developed is to realise micro-fabrication process chains in a high throughput production line. NSMZ will develop the equipment platform. To achieve the high standards for volume production, ACP will develop quality control and required control software systems. To use this kind of equipment platforms in further applications IPA and the Light-Rolls partners will develop a knowledge base for i) design for manufacturing and ii) for configuration of production lines.