Optimization of Fine Line Screen Printing Using In-Depth Screen Mesh Analysis

In today's fine line screen printing of Si-solar cells, the screen geometry plays an important role to further optimize the paste transfer while reducing electrode widths. The screen design parameters such as mesh count, wire diameter, screen angle and channel width highly influence the opened areas inside the channel. Therefore, this work presents a comprehensive study of the shape, size and location of all existing opened areas as well as the distribution of wire cross sections inside the screen channel depending on all screen design parameters. In order to analyze the data, novel evaluation parameters e.g. local open area, its standard deviation and its periodic length are introduced. It was found that screen angles of e.g. 35° show a better compromise between low standard deviation and low periodic length of the local open area and are therefore more beneficial in terms of homogeneity of the printed electrode than the industry standard of 22.5°.