Patent ID: 7994029

Claim:
A method for patterning crystalline indium tin oxide using femtosecond laser, comprising steps of: (a) providing a substrate with an amorphous ITO layer thereon; (b) transferring the amorphous ITO layer in a predetermined area into a crystalline ITO layer by emitting a femtosecond laser beam to the amorphous ITO layer in the predetermined area; generating the femtosecond laser beam using a femtosecond laser source; focusing the femtosecond laser beam using a focusing lens set; and transferring the amorphous ITO layer in the predetermined area into the crystalline ITO layer by emitting the focused femtosecond laser beam to the amorphous ITO layer in the predetermined area; and (c) removing the amorphous ITO layer on the substrate using an etching solution wherein the relation between the intensity F of the focused femtosecond laser beam and the pattern line width D of the crystalline indium-tin oxide layer satisfies D 2 =2ω 2 ln(F/Fth), wherein ω is the light spot radius of the focused femtosecond laser beam and Fth is the intensity threshold for thermal crystallization of amorphous ITO.