Screen-printing simulation study on solar cell front side AG paste

The performance of solar cell front Ag paste strongly depends on the chemical composition of the ingredients and paste rheology. The correct inorganic ingredients in the paste ensure the low contact resistance and line resistance for the front fingers. On the other side, the organic ingredients combined with other ingredients provide paste rheology, which affect not only paste stability but also printability. We discuss improvement of the printability of Heraeus front side Ag pastes in this paper. The goal of this study was to minimize time consuming printing tests by developing a screen-printing simulation program on rheology tester. We developed simulation programs that correlate paste rheology parameters to paste screen printing performance. The program focuses on simulating the screen printing process to get information on characteristics of the printed fingers like spreading and finger width uniformity, etc. The simulation response of paste SOL9848 and improved version SOL9848A was compared. A good correlation between those responses and printability was observed and discussed in this paper.