An optimization strategy for improving the aspect ratio of screen printing electronic paste based on rheological properties

The wide application of electronic pastes in the field of information electronics puts forward higher requirements for printability. As a key component to determine printability, there are few researches on the effect of organic vehicle components on printability of electronic paste. The purpose of the investigation was to explore the effects of different component contents on the properties of organic vehicles and then on the properties of electronic pastes. Experiments on the wettability of organic solvents to silicon wafers and solubility of adhesives were applied to screen organic solvents. The rheological properties of organic vehicles and electronic pastes in the optimization process were evaluated by the combined method of three interval thixotropy test (3ITT), oscillation amplitude sweep test and NMR relaxation time measurement. And the optimum ratio of adhesive, dispersant and coupling agent and the influence on rheological properties of electronic paste were determined. The optimized silver-aluminum paste as front-side paste was screen-printed and sintered to give a height/width (H/W) ratio of 0.4505 and an average resistivity of 5.06×10-6 Ω cm for the silver grid lines. The paste formulations developed in the investigation provide a new idea for the preparation and development of electronic pastes with excellent performance.