A microelectronic substrate, a method of forming the same, and a system including the same. The microelectronic substrate comprises: a conductive layer; a spacer layer disposed onto the conductive dielectric layer; a dielectric build-up layer disposed onto the spacer layer, the spacer layer being made of a material that has a lower shrinkage than a material of the embedding dielectric-build-up layer during curing, and a higher viscosity than a material of the embedding dielectric build-up layer in its pre-cure form and during curing; and active or passive microelectronic components embedded within the dielectric build-up layer.