WASHINGTON – The US PTO has issued a patent to four inventors at Endicott Interconnect Technologies for a method of making printed circuit boards with photoimageable dielectric layers in a continuous manner.

A layer of conductor is fed into the apparatus; layers of photoimageable dielectric are applied to opposite sides of the conductor layer; through-holes are formed through the composite; metal layers are added over the dielectric, and patterns are formed.

Several other operations are performed to form the end-product -- a circuitized substrate -- all while the conductor layer of the product is retained in a solid format, up to the final separation from the continuous layer.