Patent ID: 8049112

Claim:
A method of making a flexible circuit comprising: providing a chemically-etchable primary substrate layer comprising a polymer type selected from the group consisting of adhesive polyimides, liquid crystal polymers, polycarbonates, and thermoset polyimides; patterning a conductive circuit on a first surface of the primary substrate layer; bonding a first surface of an unpatterned primary cover layer comprising an adhesive polyimide polymer on the first surface of the primary substrate layer over the conductive circuit; and patterning one or both of the primary substrate layer and primary cover layer by chemical etching; wherein one or both of the primary substrate and primary cover layers comprise an adhesive polyimide, which is a polyamide-imide having the following repeating units: in which R represents a divalent radical, R′ represents a trivalent radical, and n is an integer of at least 5.