Cascaded tensioning tangential drive for tha handling

Abstract

A system and method for fabricating flexible circuits. The inventive system includes an oven and three or more independent tensioners for moving a strip of flex tape therethrough. In total, N tensioners are provided per side. The tensioners provide a cumulative tension force T on the tape and each tensioner applies T/N of the total tension. The tension is applied tangentially in a single plane of the tape along a direction parallel to the longitudinal axis thereof In the illustrative embodiment, the tensioners are sprocket wheels. Eight sprocket wheels are disposed on a supply side of the system and eight wheels are disposed on a take-up side of the system. The sprocket wheels are adapted to engage sprocket holes in the tape. The tape has a sprocket wheel area and a die area. A silicon die is typically bonded to the die area with a suitable epoxy. Copper conductors on the tape communicate electrical signals from a printer or other mechanism to the silicon die. The inventive system maintains high tension on the tape as it moves through a plurality of bake ovens. High tension is distributed over a longer area of the tape than with prior systems and is maintained without exposing the flex circuit to a stressful bend angle. In addition, each sprocket hole experiences minimal force due to the force/tension distribution methodology of the inventive system.