Patent ID: 7542152

Claim:
A method for evaluation of a thin film formed on a transparent substrate, wherein said method comprising the steps of: projecting a laser light from a single laser source of light with a single wavelength in an absorption band of the thin film on said thin film, and measuring reflection light intensity and transmission light intensity using a plurality of sensors forming at least one pair of sensors where the sensors of each pair are arranged on opposite sides of a surface of the thin film; obtaining a light absorption amount of said thin film from a linear sum of the reflection light intensity and the transmission light intensity; obtaining a thin film thickness and an in-plane distribution of the thin film thickness by using said light absorption amount; laser annealing said thin film using an annealing laser having an annealing laser energy adjusted in accordance with said obtained thin film thickness; obtaining an in-plane distribution of a grain size in said thin film after said laser annealing of the thin film; determining an optimal range of said annealing laser energy by comparing said thin film thickness in-plane distribution with said in-plane distribution of grain size so that an increase of the grain size with said thin film thickness increase indicates an excess of said annealing laser energy, and decrease of the grain size with said thin film thickness increase indicates a shortage of said annealing laser energy; and adjusting said annealing laser energy to said optimal range for processing a subsequent thin film formed on said transparent substrate.