Flexible substrate

摘要

The present invention aims to connect metal films without forming any opening in a resin film. Against a first resin film 16 formed on a first metal film 12 are pressed bumps 21 on a second metal film 11 so that the bumps 21 are embedded into the first resin film 16. Either one of the first metal film 12 or the second metal film 11 or both is (are) patterned while the bumps 21 are in contact with the first metal film 12, and the first resin film 16 is heat-treated while the top of the first resin film is partially exposed to discharge the solvent or moisture from the exposed zone and cure the first resin film 16. After curing, the bumps 21 and the first metal film 12 may be ultrasonically bonded to each other. A second resin film and a third metal film may be further layered to form a multilayer structure.