Three-dimensional integrated circuit using printed electronics

A fully printed ring oscillator circuit is reported, which has not only horizontally arranged parts, but inverter stages stacked vertically on top of each other in four through-connected substrate layers. For the preparation of the inverters exclusively gravure and flexographic printing were used. Characteristics of the stacked ring oscillator are similar to planar circuits. A very interesting path of development for printed electronics is opened with this approach, because three-dimensional circuits become possible. (C) 2010 Elsevier B.V. All rights reserved.