Abstract: The invention provides a manufacturing method of a metal-insulator-metal device, including: forming a first metal layer, an insulation layer, and a second metal layer sequentially on a base to form a metal-insulator-metal structure; forming a patterned mask layer on at least a portion of the second metal layer, etching the second metal layer and the insulation layer on which the patterned mask layer is not formed using an etchant without carbon; and cleaning the etched metal-insulator-metal structure using a mixed solution containing oxidants and metal oxide etchants to remove excess polymer remaining on the metal-insulator-metal structure.