Embodiments disclosed herein comprise package substrates and methods of forming package substrates. In an embodiment, a package substrate comprises a core substrate. A hole is disposed into the core substrate, and a via is disposed in the hole. In an embodiment, the via completely fills the hole. In an embodiment, a method of forming a package substrate comprises exposing a region of a core substrate with a laser. In an embodiment, the laser changes the morphology of the exposed region. The method may further comprise etching the core substrate, where the exposed region etches at a faster rate than the remainder of the core substrate to form a hole in the core substrate. The method may further comprise disposing a via in the hole.