The invention provides a quasi molecule
laser annealing apparatus and a preparation method of a low-temperature polysilicon thin film, for solving the problems of short effective annealing time and quite small
crystal grains during annealing of a conventional low-temperature polysilicon thin film in the prior art. In the quasi molecule
laser annealing apparatus, a heating unit is arranged at one side, which is far away from an
amorphous silicon thin film, at a substrate to be processed, for heating the substrate to the processed. The heating unit heats the substrate during the annealing process of the substrate to be processed, such that the
temperature difference between the substrate to the processed and the
amorphous silicon thin film is reduced, heat generated when
laser is irradiated on the
amorphous silicon thin film is not rapidly conducted to the substrate, the temperature reduction speed of the amorphous
silicon thin film is slowed down, the annealing time is prolonged, and fused amorphous
silicon can be conveniently annealed to form the large-
crystal-grain polysilicon thin film. Since the preparation method of the low-temperature polysilicon thin film employs the quasi molecule
laser annealing apparatus, the large-
crystal-grain polysilicon thin film can be obtained, and a polysilicon
thin film transistor with higher mobility can be obtained.