A permanent growth of the thin-film electronics market
stimulates the development of versatile technologies for patterning
thin-film materials on flexible substrates. High repetition rate lasers with
a short pulse duration offer new possibilities for high efficiency
structuring of conducting, semi-conducting and isolating films. Lasers with
the picosecond pulse duration were applied in structuring the complex
multilayered Cu(InGa)Se2 (CIGS) solar cells deposited on the polyimide
substrate. The wavelength of laser radiation was adjusted depending on
optical properties both of the film and the substrate. A narrow processing
window of laser fluence and pulse overlap was estimated with both 1064 nm
and 355 nm irradiation to remove the molybdenum backcontact off the
substrate. The selective removal of ITO, ZnO and CIGS layers was achieved
with 355 nm irradiation in the multilayer structure of CIGS without
significant damage to the underneath layers. Use of the flat-top laser beam
profile should prevent inhomogeneity in ablation. The EDS analysis did not
show residues of molybdenum projected onto the walls of ablated channel due
to melt extrusion. Processing with picosecond lasers should not cause
degradation of photo-electrical properties of the solar cells but
verification is required.