A low-cost flexible circuit on a polyester substrate

摘要

This paper describes a flexible circuit product constructed using polyester as the substrate. The cooper for the circuit traces was deposited by evaporation follwed by electro-deposition and was aptterned using a primting process. The product was delivered to the end-user with a cover coat in the non-bonding area and a z-axia conductive adhexive, suitable for thermal bonding, on the bond pads. This product is not longer available. We will describe all of these elements but will emphasize the thin film aspects of the construction. Adequate adhesion of the copper to the polyester required a two-step priming process. The polyester surface to be metallized was converted from a crystalline state to a quasi-amorphous state using a patented, pulsed optical process. The metallization consisted of a thin layer of sputtered Inconel primer followed by thickner layer of copper, evaporated from a conventional e-beam source.