WSe2, thin films are obtained by annealing tungsten and selenium constituents in thin-film form, under selenium pressure. Thin films have been investigated by X-ray analysis, scanning and transmission electron microscopy, and by microprobe analysis, Annealing temperature and time were used as parameters. It is shown that stoichiometric thin films, crystallized in the hexagonal structure, are systematically obtained. The grain-size evolution with increasing temperature and/or annealing time is interpreted in terms of primary and second crystallization processes (crystallization and recrystallization).