Method for manufacture of multilayer circuit board

Claim 1

A process for the formation of a multilayer printed circuit board, said process comprising the steps of providing a non-conductive carrier having a circuit pattern over at least one of its surfaces, applying a first permanent photo dielectric coating over the circuit pattern, exposing the permanent photo dielectric coating to activating radiation in an image pattern comprising an array of openings at locations where interconnections are desired and developing said imaged photo dielectric coating to provide photoformed openings, selectively providing an electroless plating catalyst within said photoformed openings and plating electroless copper onto said electroless plating catalyst to render the photoformed openings conductive, applying a permanent photo mask over the metalized layer of interconnections, exposing the permanent photo mask to activating radiation in an image pattern comprising an array of conductors and interconnections at desired locations, developing said imaged photo mask to provide photoformed conductor lines where conductors are desired and photoformed openings where interconnections are desired and selectively providing an electroless plating catalyst within said photoformed openings and plating electroless copper onto said electroless plating catalyst to render said photoformed openings conductive and repeating the process sequentially until the desired number of layers are formed.