Effects of Environmental Conditions on Interfacial Adhesion Between Screen-Printed Ag Film and Polyimide Substrate

Abstract

The effects of environmental conditions on the interfacial adhesion between screen-printed Ag film and polyimide substrate interface are quantitatively evaluated using the 90° peel test. The adhesion of printed patterns is varied by annealing time and atmosphere conditions. The peel strengths of air, high vacuum, and N₂ atmosphere samples increase after post-annealing for 24 h, which are closely related to the curing effect of binder in Ag paste. The peel strengths of air, high vacuum, and N₂ atmosphere samples decrease after post-annealing for 48 and 100 h. Peel strengths of samples after 48 h post-annealing in air are lower than in high vacuum and N₂, indicating the effects of post-annealing atmospheric conditions on interfacial adhesion strength. The decreased adhesion strength during post-annealing seems to be closely related to Ag₂O formation at screen-printed Ag/polyimide. Therefore, the optimum annealing conditions of Ag binder must be carefully applied to obtain maximum interfacial adhesion. Furthermore, it is important to control Ag₂O formation during environmental reliability testing.