Breakthrough in printed electronics

A world first in volume printed integrated electronics circuits was exhibited at the recent Plastics Electronics trade fair in Frankfurt. The Institute for Print and Media Technology at Chemnitz University in Germany has developed a new process that enables electronic circuitry to be produced with mass printing technology. The new process will enable the mass production of very cheap integrated circuitry in paper and cardboard and can be expected to have massive consequences in manufacturing, the future of RFID and the blurring of the line between printed objects and the virtual world.The first practical applications are expected to be electronic printed maps and printed paper keyboards, closely followed by labels for clothing, luggage, packaging, ticketing and after that … almost anything.

The circuit created for the demonstration was a ring oscillator consisting of 14 transistors. Ring oscillators are basic components for more complex circuits and generate clock signals. BASF and Bell Labs contributed their experience in material science. The circuits were designed, printed and researched by printed systems GmbH and the Institute for Print and Media Technology. The researchers tested all mass printing technologies such as offset, gravure and flexographic printing.

The circuits were printed at a printing speed of up to 0.8 metres per second which although slow for printing, is a new dimension of production speed for electronics. Millionfold print runs will become possible. The polymer printing method is based on especially developed printing methods i.e. polymer molecules that are either conductive, semiconductive or isolating are accurately printed in ultrathin layers, one above the other. These polymers can be processed similar to ink. Compared to traditional printing, however, the demands on precision as well as on the chemical characteristics of the printing inks are considerably higher. A single mistake in printing will immediately lead to malfunctions of the printed circuit.

A switching frequency of 1 Hz was achieved with the used structural resolution of 100 µm. Prof. Dr. Arved Hübler, head of the Institute for Print and Media Technology at Chemnitz University of Technology whose research team already introduced the first mass printed single transistor in 2003, explains: "We have successfully met a great challenge in this project because the printing of electronics put completely new demands on materials, methods and machines different from those known from traditional printing.

The researchers at the Institute for Print and Media Technology have realised new developments in mechanical engineering and process technology in order to meet the very high demands of electronic circuits on printing characteristics."

The project was coordinated by BASF Future Business and included researchers from BASF, Lucent Technologies Bell Labs, printed systems GmbH in Chemnitz as well as the Institute for Print and Media Technology at Chemnitz University of Technology.