Electrical evaluation of high-aspect-ratio wires formed by capillary-effect-based screen-printing

In the advancement of printed electronics industry, the development of screen-printing techniques in order to form finer wires with a higher aspect ratio is an important task. To this end, we evaluate electrical characteristics of conductive wires formed by the screen-printing process combined with an imprinting technique. We show that fine and high-aspect-ratio wires are realized by the capillary force of parallel-walled structures (PWSs) on polymer films. A printed wire with a line width of 8.4 μm and an aspect ratio of 7.9 is obtained. The printed wires act as conductive wires according to the electrical evaluation. Moreover, the electric resistances of the wires formed by the proposed process keep low values compared with the increasing trend of resistance by the conventional process. At the height of PWS from 40 to 80 μm, the average resistances are gradually decreased from 228 to 87 kΩ/mm with an increase of the height. When the height is increased from 80 to 140 μm, on the other hand, since the decrease of the resistance cannot be observed, we confirm that there is a limit to form a high-aspect-ratio wire using the screen-printing condition. The printing condition needs to be further improved in future to produce an effect on the proposed screen-printing process.