High density built-up multilayer printed circuit boards are produced by constructing microvias with photoimageable dielectric materials. A photosensitive dielectric composition on a conductive foil is laminated to conductive lines on a core. After imaging the foil and imaging and curing the photosensitive dielectric composition, vias are formed to the conductive lines. Thereafter the conductive lines are connected through the vias to the conductive foil, and then the conductive foil is patterned.