When the method of polyimide film with a copper foil bonded manufacturing polyimide CCL. Must be used on a copper foil or a polyimide film or both surfaces applied adhesive, then hot pressing the two together. Peel strength qualified product to reach 90 ° 10N / cm or higher. This is usually an epoxy adhesive or an acrylic resin, but due to the low thermal resistance of these adhesives can not meet some of the requirements of the application. Recently developed thermoplastic polyimide adhesive, so that the circuit board temperature and reliability have been improved. In recent years, the successful development of the technology is to be applied directly to the polyimide acid copper foil, and then imidization under an inert atmosphere to prevent oxidation of the copper foil. This is the so-called "adhesive polyimide laminates." But generally has a high thermal stability, bond PMDA mechanical properties and dimensional stability / ODA and BPDA / PPD film of copper is low. So we have adopted one or two-hit primer on the copper foil, increase the binding layer of polyimide and copper. Technical details in this regard is still due to commercial sensitivities rarely publicly disclosed.