Printing parameters and ink components affecting ultra-fine-line gravure-offset printing for electronics applications

Abstract

The gravure offset printing method was examined for the manufacture of thick-film conductors on alumina, using Ag based inks. In this research, a roller type gravure offset manufacturing process was developed to give conductor lines and spaces down to 20 μm, together with a low square resistance. Novel hydrocarbon resin based inks have been used and compared to traditional ethyl cellulose based inks normally used in thick-film technology. The inks had a high viscosity compared to graphical inks due to their high solid content, which was necessary to enable a high printed mass. Different printing parameters were studied and printed sample properties were statistically compared. The results show that the cross sectional area of the lines is the best correlating measured property to describe the quality of the printing. 100% of the ink was transferred from the blanket to the substrate after 30 seconds. Prints from ink containing 85 wt.% of silver with optimised parameters resulted in a square resistance of 5 mΩ/sq. for 300 μm wide and 17 μm thick lines produced from a single print. These promising results are important requirements for high throughput electronics manufacture.