IDTechEx recently visited South Korea as part of a UK Trade and Investment mission. During our stay, we visited a number of Korean companies and research institutes including InkTec, Samsung Electronics, LG Chemicals, Korea Institute of Advanced Technology, Korea Advanced Nano Fab Centre, Korea Research Institute of Chemical Technology, etc. Below we summarise some highlights of the trip:
InkTec supply a range of different printable conductive inks. They also have a roll-to-roll printing factory with web widths of 1600 mm. In terms of inks, they offer a range of conductive inks based on silver flakes, silver nanoparticles and silver ions. They both manufacture the nanoparticles and formulate the inks. The main benefits that nanoparticle inks offer are (a) inkjet printability and (b) the ability to tune or enhance the conductivity of flake inks by filling in the gap between flakes.
InkTec also supplies particle-free silver ion conductive inks. This ink is transparent (yellowish) initially but turns into silver when printed. The primary advantages that this ink offers are (a) a very smooth mirror-like finish and (b) no clogging of inkjet printer nozzles. This product can compete with sputtered and evaporated silver in terms of performance, while undercutting it in terms of costs. The primary target applications include anti-reflectors in display, design products requiring a mirror-like finish (e.g., replacing chrome on car tyres), etc
InkTec is also active in printing RFID antennas, transparent conductors, and memories. They can roll-to-roll gravure print RFID antennas (mostly using nanoparticle inks) on PET and paper. They however acknowledge that this is a challenging market because the incumbent technology works well and is cheap.
They also manufacture flexible transparent conductors based on very fine (3-5 um) metallic grids. They use a hybrid manufacturing approach to reach these resolutions. Here, the substrate is initially coated with a layer of photoresist. The grid pattern is subsequently developed using photolithography, which is a subtractive process.
The metallic tracks are finally printed over the patterned grid. The final structure is obtained by etching the photoresist, which will undercut the printed lines, leaving silver tracks only where required. This approach is therefore halfway between fully additive printing and fully subtractive photolithography.
InkTec and Thin Film have a partnership to gravure print flexible memory units. Thin Film brings the memory technology to the table, while InkTec performs the printing. Here, the memory consists of five layers, printed on top of one another. The main printing challenges to tackle here are yield and alignment. Also critically, the conductive tracks must be very smooth in order to avoid creating a defect (and thus a short circuit) within the vertical memory stack.
InkTec also focus on the Printed Circuit Board (PCB) market. Traditionally, the manufacturing of PCBs has been a subtractive process in which copper is first coated over the entire surface, before being patterned and etched. InkTec uses an additive approach in which a silver seed layer is first printed only where required. The seed lines are then thickened by plating the copper. This way the higher cost of silver is compensated by reductions in copper usage.
Korea Institute of Science and Technology (KIST)
Their main activity in printed electronics was setting up a roll-to-roll photo-curing system. The system was developed in-house. Currently, the printing of RFID antennas has been demonstrated. In the near to medium term, the research group aims to develop photo-cured solution-processed thin film transistors. The active channel is likely to be an oxide semiconductor. The material of choice for other layers is still not clear.
In addition to this, they also have research on producing silver nanoparticles, organic photovoltaics, and inkjet printing thin film transistors. These are mainly R&D driven.
Photo-curing systems have been popular in printed electronics. Several companies use this approach to cure metallic inks (copper oxide, copper, silver, etc). The main advantages are that this roll-to-roll approach is fast and compatible with low temperature substrates such as paper.
Samsung Electronics opened the meeting by giving an overview of printed electronics. During their presentation, they employed IDTechEx forecasts and analysis to justify their activities.
According to Samsung, the main value proposition that Printed Electronics offers lies in cost savings. This is because printing is additive, which immediately suggests that material wastage can be minimised. Moreover, the equipment set-up costs are expected to be lower than traditional vacuum-based systems.
Samsung however acknowledge that mastering the art of printing is tricky. They indicate that challenges with the control of resolution, underfill, overfill, wavey lines, etc still remain. This explains why in the short term they anticipate simpler applications such as inkjet printing of colour filters on LCD displays. They acknowledge that critical issues persist with printing thin film transistors for display backplane. These issues are yield, threshold voltage instability, uniformity, etc. In spite of these difficulties, Samsung is keeping some 100 researchers across all departments dedicated to printed electronics.
KOPEA and Korean Advanced Nano Fab Centre
Korea Printed Electronics Association (KOPEA) hosted a meeting at the Korean Advanced Nano Fab Centre, which has an impressive cleanroom. KOPEA, which brings together some 70 Korean institutes and companies, mentioned that the South Korean government wishes to invest $48 million in printed electronics over the next six years. This investment is mainly at R&D level, but players are actively encouraged to look for ways of commercialising and internationalising their work.
This indicates opportunities for non-Korean players to foster partnerships with Korean companies. KOPEA is currently spearheading the efforts to select four promising sub-topics of printed electronics for further investigation, and to develop industry standards.
For more information attend Printed Electronics Asia in Tokyo, Japan on October 2-3 - the key event to learn and network with the leaders in printed electronics in Asia. See Printed Electronics Asia, October 2-3, 2012to register early for the best savings.