Method for manufacturing electronic device

摘要

To provide a method for forming an opening with high accuracy in an insulating film obtained by curing a prepreg including a reinforcing material in a step of exposing a terminal portion sealed with the insulating film, with the use of a means other than laser beam irradiation. A protrusion is formed using a conductor. An uncured prepreg including a reinforcing material is closely attached to the protrusion and the prepreg is cured, so that an insulating film including the reinforcing material is formed. A portion of a top surface of the insulating film protrudes due to the protrusion. The protruding portion is preferentially removed together with the reinforcing material to form an opening in the insulating film by grinding treatment or the like, so that an opening which exposes the protrusion is formed in the insulating film.