Patent ID: 7829794

Claim:
A method of making a partially rigid flexible circuit comprising: providing a rigid multi-layer structure having a first polymer layer, a patterned conductive layer on the first polymer layer, a chemically-etchable polyimide adhesive layer on the patterned conductive layer, and a chemically-etchable second polymer layer on the chemically-etchable polyimide adhesive layer wherein the chemically-etchable polyimide adhesive layer comprises 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; and removing a portion of the chemically-etchable second polymer layer and the chemically-etchable polyimide adhesive layer by chemical etching to expose at least a portion of the patterned conductive circuit layer and form a flexible portion in the rigid multi-layer structure.