Inspection of thin-film solar cell processing by laser-induced breakdown spectroscopy and neural networks

Laser scribing is used in the manufacturing process of thin-film solar cells. Selective material ablation is required to remove the desired layers while minimizing the damage caused to the rest of the structure with the aim of improving efficiency of solar cells and reducing production costs. To that end, laser-induced breakdown spectroscopy (LIBS) assisted by artificial neural networks (ANN) was implemented as monitoring tool during laser scribing. The performance of this method to identify transition between layers presented low error and high precision. Therefore, the feasibility of using plasma emission spectra for inspection of solar cell processing was demonstrated.