FILM CARRIER AND FILM CARRIER DEVICE, AND MANUFACTURE OF FILM CARRIER

摘要

PURPOSE:To limit noise due to high-frequency current while improving connection reliability by forming via holes having a specific cross section. CONSTITUTION:Two metal sheets 1 and 2 are coated on one surface with polyimide 3 and 4, respectively, and heated to dry the polyimide. The sheets are joined with polyimide 3 and 4 in contact using polyimide varnish. A via hole 6 is opened through the metal sheet 2, polyimide 4 and polyimide varnish 5. The cross section of the via hole is wider at least 1 micron at the polyimide varnish 5 than at the metal sheet 2. This improves the adhesion to a metal film 7 that is formed later, thus improving connection reliability.