The researchers have developed screen printing frames with meshes that can print extremely fine lines. They explain that printing electronic circuits with a line width of approximately 100 micrometres places high demands on the print technology, and this was only possible due to the graphics industry.
Peter Andersson Ersman, researcher in printed electronics at the RISE research institute, commented, “The advantage we have here is that we do not need to mix different manufacturing methods: everything is done by screen printing, and in relatively few processing steps. The key is ensuring that the different layers end up in exactly the right place.”
The researchers did this through reducing the circuit size, increasing the quality so that all transistors in the circuit work as close to 100% of the time as possible, and through solving integration with the silicon-based circuits needed to process signals and to communicate with the surroundings.
“One of the major advances is that we have been able to use printed circuits to create an interface with traditional silicon-based electronic components. We have developed several types of printed circuits based on organic electrochemical transistors. One of these is a shift-register, which can form an interface and deal with the contact between the silicon-based circuit and other electronic components such as sensors and displays. This means that we can now use a silicon chip with fewer contacts, which needs a smaller area and is in this way cheaper”, explained Magnus Berggren, professor of organic electronics and director of LOE.
The development of ink to print the thin lines and improvements of the screen printing frames have contributed not only to the miniaturisation process, but also to achieving higher quality.
“All-Printed Large-Scale Integrated Circuits Based on Organic Electrochemical Transistors” was first published in Nature Communications. It is authored by Peter Andersson Ersman, Roman Lassnig, Jan Strandberg, Deyu Tu, Vahid Keshmiri, Robert Forchheimer, Simone Fabiano, Göran Gustafsson and Magnus Berggren.