Inkjet printing of 3D metal-insulator-metal crossovers

The inkjet deposition of a single functional material on a substrate is well developed, however, little attention has been paid to the sequential printing of different functional elements to generate complex 3D structures. The successful all additive manufacture of electronics circuits requires the printing of features such as crossovers and interconnections, the passive elements in electronics where metal-insulator-metal must be sequentially deposited with retained function. We describe the inkjet printing of both a commercial silver nanoparticle metal and a cationic/thermally cured epoxy insulator, SU8, and discuss the role of print strategy and surface treatment on retaining functionality. The issues to be addressed in the successful all inkjet printing of such features are discussed. (C) 2008 Elsevier Ltd. All rights reserved.