Feature Size Control by Layer-by-Layer Printing and Non-wettable Patterns for Inkjet Printing of Micro Metal Electrode

Abstract

The feature size and resolution of inkjet printing is limited by nozzle size, jetting volume and ink spreading. This study proposes a unique inkjet printing method for controlling feature sizes such as line width and thickness for the fabrication of mciro metal electrodes. To form the micro metal electrodes, we printed silver (Ag) ink inside a hydrophilic track formed by a printed non-wettable patterns. The minimum line width of the printed Ag could be reduced up to 18 μm by using the jetted ink droplet of 35 ± 4.2 μm diameter, which is twice the line width. To increase the thickness of the microelectrode, Ag ink was repeatedly printed layer-by-layer, and the thickness could be increased to 1 μm for an 18 μm width. After optimizing the printing conditions for a straight line, the fabrication of a micro-grid electrode was demonstrated, by first printing a horizontal electrode pattern, then a vertical electrode pattern was printed by repeating the proposed printing method. Also, we investigated the sheet resistance of the Ag grid-printed ITO-coated glass substrate by changing the grid space distance.