Abstract: A method is disclosed for making circuitized, flexible film substrates in a continuous tape format using a transfer technique. The tape is made with window-like openings having a relatively thin layer of polyimide spanning the openings. The relatively thin layer of polyimide is transferred to the tape from a metal carrier foil, preferably by using a special adhesive system. After the polyimide is transferred to the tape, the polyimide spanning the window-like openings in the tape is circuitized to form individual, circuitized, flexible film substrates which may be handled in the tape format for further processing. Preferably, the tape includes perforations for engaging sprockets of automated manufacturing equipment, or the like.