The field of laser treatment on semiconductor materials is still displaying new important developments. Driven by the application to flat panel displays, excimer laser sources are being widely employed for the crystallization of silicon thin films. They are integrated with mass-production equipments and with techniques that control the location and orientation of the micro-grains, and this method allows to obtain thin film large-grain polycrystalline silicon whose carrier mobility is approaching silicon-on-insulator at a laboratory scale. Nowadays there is an increasing development of methods for improving the crystal fraction, the surface flatness, the grain arrangement on small and large areas. The method seems to be the only lasting approach to obtain high performance on flexible plastic substrates, unrivaled by devices based exclusively on organic materials. Here, the progress of recrystallized silicon obtained by excimer laser irradiation is reviewed, and its evolution is linked with the past decades of laser treatment of semiconductor materials. The advanced results obtained on glass are extrapolated to the case of polymer substrates.