Time-resolved study of polyimide absorption layers for blister-actuated laser-induced forward transfer

Blister-actuated laser-induced forward transfer (BA-LIFT) is a versatile, direct-write process capable of printing high-resolution patterns from a variety of sensitive donor materials without damage to their functionality. In this work, we use time-resolved imaging to study the laser-induced formation of blisters on polyimide films in order to understand and optimize their role in BA-LIFT. We find that the initial blister expansion occurs very rapidly ( < 100 ns ) , followed by a brief oscillation (100-500 ns), and then a longer time contraction to steady-state dimensions ( 0.5 - 50 μ s ) . This behavior is explained by kinetic and thermal effects that occur during the process. We further probe the influence of polyimide thickness, laser beam diameter, and laser fluence on blister formation characteristics. Results indicate that the presence of a thin layer of donor material on the polyimide surface does not have a significant effect on the size and shape of the blisters which form.