Digital Fabrication Using High-resolution Liquid Toner Electrophotography

Abstract

We have developed a digital fabrication process using high-resolution liquid toner electrophotography, consisting of fine liquid toner, a high-resolution exposure system, and nonelectrical transfer. Fine pitch multiline patterns of Cu wiring can be obtained by printing fine lines with seed toners and by electroless plating deposited on lines. Submicron-diameter seed toners have superfine conductive particles on their surfaces. Adhesion between the seed toner layer and Cu layer was increased by applying surface modification. Multiline patterns of 1 pixel line width (21.6 m) with the volume resistivity of 2.1ϫ 10 −6 Ωcm were realized by using a 1200 dpi resolution light-emitting diode. Furthermore, the development process of multiline patterns with 2540 dpi resolution was examined by numerical simulations based on the electrophoretic characteristics of liquid toner and on the electrostatic forces. The capability of multiline-pattern formation of line and space (L/S)ϭ10/10 m was confirmed. The actual toner images of L/Sϭ10/10 m multiline pattern were obtained by using a 2540 dpi resolution luster scanning unit (LSU). Theoretical and experimental results confirm that the fabrication process using liquid toner electrophotography is available for realizing high-resolution multiline patterns.