Fabrication of high-resolution conductive lines by combining inkjet printing with soft lithography

Abstract

In this study, an effective method to fabricate well-defined conductive lines with high resolution has been proposed by combining inkjet printing with soft lithography. Soft lithography techniques such as nanoimprint lithography for negative SU-8 patterns and micro-contact printing for hydrophobic fluorocarbon layer were used to create surface wettability contrasts so that the spreading of droplets was confined on a hydrophilic region surrounded by hydrophobic regions. Surface wettability contrasts were evaluated by water contact angle measurements, and the maximum contact angle difference between hydrophobic and hydrophilic surfaces was 104 degrees. With the help of such surface wettability contrasts and lift-off process for removing small amount of ink stains, well-defined inkjet-printed lines as narrow as 2.8 mu m can be successfully generated. The sintered Ag lines also show good electrical resistivity of 7.6 mu Omega.cm, 4.7 times as large as bulk Ag's resistivity. This combined approach can be used to fabricate high-quality, high-resolution electrodes in printed electronics applications. (C) 2013 Elsevier B.V. All rights reserved.