A substrate comprising a solid glass core having a first surface and a second surface opposed to the first surface; multiple conductors extending through the solid glass core beginning at the first surface and ending at the second surface, wherein one of the conductors has a third surface and a fourth surface, wherein the third surface and the first surface are substantially coplanar, wherein the second surface and the fourth surface are substantially coplanar, wherein one of the conductors comprise a copper-tungsten alloy material, wherein the solid glass core is directly contact with the conductor; and a first dielectric layer and a first metal layer formed at the first surface, wherein the first metal layer at the first surface is electrically coupled with one of the conductors.