A semiconductor package substrate suitable for supporting a damage-sensitive device, including a substrate core having a first and opposite surface; at least one pair of metal layers covering the first and opposite surfaces of the package substrate core, which define first and opposite metal layer groups, at least one of said layer groups including at least one metal support zone; one pair of solder mask layers covering the outermost metal layers of the at least one pair of metal layers; and a plurality of routing lines; wherein the at least one metal support zone is formed so that it lies beneath at least one side of the base of the damage-sensitive device and so as to occupy a substantial portion of the area beneath the damage-sensitive device which is free of said routing lines; a method for the production of such substrate is also described.