Want a plastic circuit? Soon, engineers might just press print.
That was the promise of a presentation given last week at the 2011 International Solid-State Circuits Conference (ISSCC). Anis Daami, an engineer at the French technology research organization CEA-LITEN located in Grenoble, detailed the performance of a menagerie of elementary organic digital and analog circuits--inverters, ring oscillators, current mirrors, and differential pairs. These simple organic circuits themselves were not the impressive part. What caught the crowd's attention was their simple birth--fully printed on plastic substrates.
"The most important challenge for organic technologies," Daami says, "is to have low cost processes that can be scalable to large areas." Printing big organic circuits could allow cheaper versions of some big electronics, such as large-area sensors.
Daami's team started with a 10-centimeter-squared gold-plated piece of plastic (polyethylene-naphtalate), which was 125-micrometers thick. After using laser ablation to remove all of the gold except what was needed for a level of electrodes and interconnects, they screen-printed semiconductors on the foil and heated it all to 100 degrees Celsius. Then they screen-printed a dielectric polymer and heated the assembly again. Finally, they printed another level of interconnects using a silver ink before giving the chip one last 100-degree Celsius toasting. The video above shows the screen-printing technique on a 320 by 380 squared millimeter substrate, what Daami says was a test to check the capability of printing a silver paste.
Though Kris Myny of Imec notes that his plastic processor required a more advanced organic circuit than those created using this technique, he said that Daami's work was impressive and seemed an important step towards making organic devices much cheaper.
Video: Anis Daami, CEA-LITEN